Pressure closed loop control oil circuit

Abstract

The present invention discloses a pressure closed-loop control oil circuit, including a shot oil cylinder, an oil tank, an oil pump, a fast accumulator, an oil pipeline with a plurality of electric control valves and a control unit. The internal cavity of the shot oil cylinder includes a boost rodless cavity with a boost inlet, a boost rod cavity with a boost outlet, a shot rodless cavity with a shot inlet, and a shot rod cavity with a shot outlet. The electric control valves in the oil pipeline are all electrically connected to the control unit. The oil pipeline includes a shot control pipeline, a shot outlet closed-loop control pipeline, a boost control pipeline, a boost outlet closed-loop control pipeline, a boost reset filling pipeline, a boost reset oil return pipeline, an accumulator control pipeline, a hammer front control pipeline and a hammer return pipeline. The pressure control of the present invention is an outlet single closed-loop control, and the back pressure of the boost rod cavity is changed by adjusting the boost return oil control pipeline, thereby adjusting the boost pressure and boost time.

Description

Technical Field

[0001] The invention relates to the technical field of die-casting machines, and in particular to a pressure closed-loop control oil circuit. Background Art

[0002] The pressure amplification function is often used in the current industry. Our common method is to use a booster piston to achieve a fixed boost ratio to achieve pressure amplification. When the booster piston inlet pressure is constant, the boost pressure is a fixed value.

[0003] In the use of equipment, the first thing that often happens is to change the mold. At this time, process adjustments need to be made, including the adjustment of the boost pressure. Because it needs to be debugged repeatedly, the boost pressure will be changed frequently. Because the boost ratio of the boost method we are currently using is fixed, when the pressure at the inlet of the injection piston, that is, the accumulator pressure, is constant, the boost pressure is a fixed value. At this time, if you want to adjust the boost pressure, you must repeatedly adjust the accumulator pressure; sometimes, the nitrogen pre-charge pressure is too high, and when the accumulator needs to store a lower pressure, the oil storage is insufficient, resulting in the need to release nitrogen to meet the oil storage capacity; when the nitrogen is released, the nitrogen pre-charge pressure is reduced, and when it is necessary to store a higher pressure, the accumulator may be full of oil and cannot reach the higher energy storage target value. At this time, nitrogen needs to be filled again, and such repeated operations are more troublesome. Secondly, the accumulator device itself will have a certain amount of leakage, which will affect the normal operation of the accumulator over time. At this time, it is necessary to refill nitrogen to meet normal production needs.

[0004] In order to extend the nitrogen filling cycle caused by leakage and solve the problem of nitrogen release or replenishment caused by the process adjustment after mold replacement, we need to make further improvements in pressurization. Summary of the invention

[0005] The present invention proposes a pressure closed-loop control oil circuit to solve the above technical problems.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A pressure closed-loop control oil circuit, comprising an injection oil cylinder, an oil tank, an oil pump, a fast accumulator A1, an oil pipeline with a plurality of electric control valves and a control unit, wherein the internal cavity of the injection oil cylinder comprises a boost rodless cavity with a boost inlet, a boost rod cavity with a boost outlet, an injection rodless cavity with an injection inlet, and an injection rod cavity with an injection outlet, and the electric control valves in the oil pipeline are all electrically connected to the control unit; the oil pipeline comprises: an injection control pipeline connecting the fast accumulator A1 and the injection inlet, an injection outlet closed-loop control pipeline connecting the injection outlet and the oil tank, and a boost inlet and a fast injection outlet closed-loop control pipeline connecting the boost inlet and the ... The boost control pipeline of the accumulator A1, the boost outlet closed-loop control pipeline connecting the boost outlet and the oil tank, the boost reset filling pipeline connecting the boost outlet and the oil tank, the boost reset oil return pipeline connecting the boost inlet and the oil tank, the accumulator control pipeline connecting the oil pump and the fast accumulator A1, the hammer front control pipeline connecting the oil pump and the injection inlet, and the hammer return pipeline connecting the oil pump and the injection outlet; the single closed-loop control of the injection outlet speed is realized by the control unit and the outlet closed-loop control pipeline, and the back pressure of the boost rod chamber is changed by adjusting the boost return oil control pipeline, thereby realizing the single closed-loop control of the boost outlet pressure.

[0008] Preferably, the injection outlet is connected to a pressure sensor R1 and / or a pressure gauge B1; the injection inlet is connected to a pressure sensor R2 and / or a pressure gauge B2; the nitrogen charging port of the fast accumulator is connected to a pressure sensor R3 and / or a pressure gauge B3; the pressure sensor R1, the pressure sensor R2, and the pressure sensor R3 are all electrically connected to the control unit.

[0009] Preferably, the hammer front control pipeline includes a manual hammer front valve V3, a hammer front control valve V5, a shuttle valve V6, a high-pressure stop valve V11, a high-pressure stop control valve V12, and a pressure-injection safety valve V13; the return hammer pipeline includes a return hammer control valve V1, a return hammer valve V2, a return hammer oil return valve V4 and a return hammer check valve V18; one end of the manual hammer front valve V3, one end of the return hammer valve V2, and one end of the shuttle valve V6 are all connected to the oil pump, one end of the return hammer oil return valve V4, and one end of the pressure-injection safety valve V13 are all connected to the oil tank, the other end of the manual hammer front valve V3 and the other end of the return hammer oil return valve V4 are all connected to one end of the high-pressure stop valve V11, and the high-pressure stop valve V11 The other end of the shuttle valve V6 and the other end of the injection safety valve V13 are connected to the injection inlet, the other end of the shuttle valve V6 is connected to one end of the hammer front control valve V5 and one end of the return hammer control valve V1, one end of the return hammer check valve V18 is connected to the injection outlet, and the other end of the return hammer valve V2 is connected to the other end of the return hammer check valve V18; the hammer front control valve V5, the high-pressure cut-off control valve V12, the return hammer control valve V1, and the injection safety valve V13 are electrically connected to the control unit respectively, the hammer front control valve V5 controls the switch of the manual hammer front valve V3 and the return hammer oil return valve V4, the high-pressure cut-off control valve V12 controls the switch of the high-pressure cut-off valve V11, and the return hammer control valve V1 controls the switch of the return hammer valve V2.

[0010] Preferably, the accumulator control pipeline includes an accumulator valve V9, an accumulator control valve V10 and an accumulator oil discharge valve V8, the accumulator control valve V10 and the accumulator oil discharge valve V8 are electrically connected to the control unit respectively, the accumulator control valve V10 controls the switch of the accumulator valve V9, one end of the accumulator valve V9 is connected to the oil pump, one end of the accumulator oil discharge valve V8 is connected to the oil tank, and the other end of the accumulator valve V9 and the other end of the accumulator oil discharge valve V8 are both connected to the fast accumulator A1.

[0011] Preferably, the injection outlet closed-loop control pipeline includes a quick-discharge proportional valve V17 and a pilot accumulator A2. The quick-discharge proportional valve V17 is electrically connected to the control unit. The two ends of the quick-discharge proportional valve V17 are respectively connected to the injection outlet and the oil tank. The pilot accumulator A2 is connected to the pilot oil circuit of the quick-discharge proportional valve V17.

[0012] Preferably, the injection control pipeline includes a fast hammer front valve V27 and a fast control valve V26, the fast control valve V26 is electrically connected to the control unit, the fast control valve V26 controls the switch of the fast hammer front valve V27, and the two ends of the fast hammer front valve V27 are respectively connected to the fast accumulator and the injection inlet.

[0013] Preferably, the boost control pipeline includes a boost valve V23, a boost throttle valve V24, and a boost control valve V25. The two ends of the boost valve V23 are respectively connected to the fast accumulator A1 and the boost inlet. The boost proportional safety valve V25 is electrically connected to the control unit. The boost control valve V25 controls the switch of the boost valve V23. The boost throttle valve V24 is used to adjust the opening of the boost valve V23.

[0014] Preferably, the boost control pipeline further includes a boost safety valve V22, the boost safety valve V22 is electrically connected to the control unit, and both ends of the boost safety valve V22 are connected to the boost inlet and the fuel tank respectively.

[0015] Preferably, the boost outlet closed-loop control pipeline includes a pilot accumulator A3 and a boost oil return proportional valve V19, one end of the boost oil return proportional valve V19 is connected to the boost outlet, and the other end of the boost oil return proportional valve V19 is connected to the oil tank, and the boost oil return proportional valve V19 is electrically connected to the control unit.

[0016] Preferably, the boost reset filling pipeline includes a boost return filling valve V14 and an active boost return filling valve V20, one end of the boost return filling valve V14 and the active boost return filling valve V20 are connected to the boost outlet, the other end of the boost return filling valve V14 and the active boost return filling valve V20 are connected to the oil tank, and the active boost return filling valve is electrically connected to the control unit.

[0017] Preferably, the boost reset oil return pipeline includes a boost return oil valve V21, one end of the boost return oil valve V21 is connected to the boost inlet, and the other end of the boost return oil valve V21 is connected to the oil tank.

[0018] Preferably, an air filter is also included, and the air filter is connected to the fuel tank.

[0019] Preferably, an oil filter is further included, one end of which is connected to the fast accumulator A1, and the other end of which is connected to a one-way valve.

[0020] Compared with the prior art, the pressure control of the present invention is an outlet single closed-loop control, which changes the back pressure of the boost rod chamber by adjusting the boost return oil control pipeline, thereby adjusting the boost pressure and boost time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the pressure closed-loop control oil circuit of the present invention.

[0022] In the figure, 1-injection oil cylinder, 2-oil tank, 3-oil pump, 11-boost rodless chamber, 12-boost rod chamber, 13-injection rodless chamber, 14-injection rod chamber. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0024] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0025] like Figure 1 As shown, a pressure closed-loop control oil circuit includes an injection oil cylinder 1, an oil tank 2, an oil pump 3, a fast accumulator A1, an oil pipeline with a plurality of electronically controlled valves and a control unit, wherein the internal cavity of the injection oil cylinder 1 includes a pressurized rodless cavity 11 with a pressurized inlet, a pressurized rod chamber 12 with a pressurized outlet, an injection rodless cavity 13 with an injection inlet, and an injection rod cavity 14 with a first injection outlet and a second injection outlet, and the electronically controlled valves in the oil pipeline are all electrically connected to the control unit.

[0026] The oil delivery pipeline includes: an injection control pipeline connecting the fast accumulator A1 and the injection inlet, an injection outlet closed-loop control pipeline connecting the injection outlet and the oil tank 2, a boost control pipeline connecting the boost inlet and the fast accumulator A1, a boost outlet closed-loop control pipeline connecting the boost outlet and the oil tank 2, a boost reset filling pipeline connecting the boost outlet and the oil tank 2, a boost reset oil return pipeline connecting the boost inlet and the oil tank 2, an accumulator control pipeline connecting the oil pump 3 and the fast accumulator A1, a hammer front control pipeline connecting the oil pump 3 and the injection inlet, and a hammer return pipeline connecting the oil pump 3 and the injection outlet. The single closed-loop control of the injection outlet speed is realized by the control unit and the outlet closed-loop control pipeline; the back pressure of the boost rod chamber 12 can be changed by adjusting the boost outlet closed-loop control pipeline, thereby realizing the single closed-loop control of the boost outlet pressure.

[0027] The injection outlet is connected to a pressure sensor R1 and / or a pressure gauge B1 for detecting the pressure value of the injection outlet; the injection inlet is connected to a pressure sensor R2 and / or a pressure gauge B2 for detecting the pressure value of the injection inlet; the nitrogen charging port of the fast accumulator is connected to a pressure sensor R3 and / or a pressure gauge B3 for detecting the pressure value of the nitrogen in the fast accumulator; the pressure sensors R1, R2 and R3 are all electrically connected to the control unit, and transmit the detected pressure value data to the control unit.

[0028] The front-hammer control pipeline includes a manual hammer front valve V3, a hammer front control valve V5, a shuttle valve V6, a high-pressure stop valve V11, a high-pressure stop control valve V12, and a pressure-injection safety valve V13; the return-hammer pipeline includes a return-hammer control valve V1, a return-hammer valve V2, a return-hammer oil return valve V4, and a return-hammer check valve V18; one end of the manual hammer front valve V3, one end of the return-hammer valve V2, and one end of the shuttle valve V6 are all connected to the oil pump 3, one end of the return-hammer oil return valve V4, and one end of the pressure-injection safety valve V13 are all connected to the oil tank 2, the other end of the manual hammer front valve V3, and the other end of the return-hammer oil return valve V4 are all connected to one end of the high-pressure stop valve V11, and the other end of the high-pressure stop valve V11, The other end of the injection safety valve V13 is connected to the injection inlet, the other end of the shuttle valve V6 is connected to one end of the hammer front control valve V5 and one end of the return hammer control valve V1, one end of the return hammer check valve V18 is connected to the injection outlet, and the other end of the return hammer valve V2 is connected to the other end of the return hammer check valve V18; the hammer front control valve V5, the high-pressure stop control valve V12, the return hammer control valve V1, and the injection safety valve V13 are electrically connected to the control unit respectively, the hammer front control valve V5 controls the switch of the manual hammer front valve V3 and the return hammer oil return valve V4, the high-pressure stop control valve V12 controls the switch of the high-pressure stop valve V11, and the return hammer control valve V1 controls the switch of the return hammer valve V2. The inlet of the shuttle valve V6 is connected to the oil pump 3 and the fast accumulator A1 to ensure the stability of the pilot oil.

[0029] The accumulator control pipeline includes an accumulator valve V9, an accumulator control valve V10 and an accumulator oil discharge valve V8. The accumulator control valve V10 and the accumulator oil discharge valve V8 are electrically connected to the control unit respectively. The accumulator control valve V10 controls the switch of the accumulator valve V9. One end of the accumulator valve V9 is connected to the oil pump 3, one end of the accumulator oil discharge valve V8 is connected to the oil tank 2, and the other end of the accumulator valve V9 and the other end of the accumulator oil discharge valve V8 are both connected to the fast accumulator A1. When the accumulator oil discharge valve V8 is opened, the oil of the fast accumulator A1 can enter the oil tank 2; when the accumulator oil discharge valve V8 is closed, the oil of the fast accumulator A1 can be prevented from entering the oil tank 2.

[0030] The injection outlet closed-loop control pipeline includes a quick-discharge proportional valve V17 and a pilot accumulator A2. The quick-discharge proportional valve V17 is electrically connected to the control unit. The two ends of the quick-discharge proportional valve V17 are respectively connected to the injection outlet and the oil tank 2. The pilot accumulator A2 is connected to the pilot oil circuit of the quick-discharge proportional valve V17.

[0031] The pilot accumulator A2 is connected to the quick-discharge proportional valve V17, so as to provide pilot pressure oil to the quick-discharge proportional valve V17. In particular, the pilot accumulator A2 is also connected to a one-way valve V15, which is used to isolate the pilot accumulator A2 from the pilot accumulator A3.

[0032] The injection control pipeline includes a fast hammer front valve V27 and a fast control valve V26. The fast control valve V26 is electrically connected to the control unit. The fast control valve V26 controls the switch of the fast hammer front valve V27. The two ends of the fast hammer front valve V27 are respectively connected to the fast accumulator and the injection inlet.

[0033] The boost control pipeline includes a boost valve V23, a boost throttle valve V24, and a boost control valve V25. The two ends of the boost valve V23 are respectively connected to the fast accumulator A1 and the boost inlet. The boost proportional safety valve V25 is electrically connected to the control unit. The boost control valve V25 controls the switch of the boost valve V23. The boost throttle valve V24 is used to adjust the opening of the boost valve V23.

[0034] In one embodiment of the present invention, the boost control pipeline includes a boost safety valve V22, the boost safety valve V22 is electrically connected to the control unit, and both ends of the boost safety valve V22 are connected to the boost inlet and the fuel tank respectively.

[0035] The boost outlet closed-loop control pipeline includes a pilot accumulator A3 and a boost oil return proportional valve V19. One end of the boost oil return proportional valve V19 is connected to the boost outlet, and the other end of the boost oil return proportional valve V19 is connected to the oil tank 2. The boost oil return proportional valve V19 is electrically connected to the control unit.

[0036] The pilot accumulator A3 is connected to the boost oil return proportional valve V19, so that the pilot pressure oil can be provided to the boost oil return proportional valve V19.

[0037] In one embodiment of the present invention, the boost reset filling pipeline includes a boost return filling valve V14 and an active boost return filling valve V20, one end of the boost return filling valve V14 and the active boost return filling valve V20 are connected to the boost outlet, the other end of the boost return filling valve V14 and the active boost return filling valve V20 are connected to the oil tank, and the active boost return filling valve is electrically connected to the control unit.

[0038] In one embodiment of the present invention, the boost reset oil return pipeline includes a boost return oil valve V21, one end of the boost return oil valve V21 is connected to the boost inlet, and the other end of the boost return oil valve V21 is connected to the oil tank.

[0039] In addition, the oil pipeline also includes an air filter F1 for air filtration and an oil filter F2 for oil filtration. The air filter F1 is connected to the oil tank 2. One end of the oil filter F2 is connected to the fast accumulator A1. The other end of the oil filter F2 is connected to a one-way valve V28. The one-way valve V28 is used to isolate the pilot accumulator A2 and the pilot accumulator A3.

[0040] The pressure control of the present invention is a closed-loop control. The boost inlet pressure is constant, the boost output pressure can be adjusted arbitrarily, and the effect of staged boosting can be achieved. The pressure building time is within 20ms.

[0041] The operation actually used in the present invention is as follows:

[0042] 1. Preparation stage: Before the injection action, the hammer return signal and the fast accumulator pressure signal are detected. When the pressure detection value of the pressure sensor R3 is lower than the set value, the energy storage action is performed: the oil pump 3 supplies oil, the energy storage control valve V10 and the energy storage oil discharge valve V8 are powered and work under the electronic control of the control unit, the energy storage valve V9 is opened under the control of the energy storage control valve V10, and the energy storage oil discharge valve V8 prevents the fast accumulator A1 from discharging oil, thereby allowing the fast accumulator A1 to store energy; when the pressure detection value of the pressure sensor R3 reaches the set value, stop storing energy and enter the next step.

[0043] 2. Manual pre-hammer action: oil pump 3 supplies oil, pre-hammer control valve V5, accumulator oil discharge valve V8, injection safety valve V13, and quick-discharge proportional valve V17 are powered and work under the electronic control of the control unit, manual pre-hammer valve V3 is opened under the control of pre-hammer control valve V5, high-pressure stop valve V11 is opened under the control of high-pressure stop control valve V12, and the injection piston rod moves forward to perform manual pre-hammer action. This action is used for preliminary debugging and later maintenance.

[0044] 3. Slow hammer pre-action: The fast accumulator A1 supplies oil, the accumulator oil discharge valve V8, the high pressure cut-off control valve V12, the injection safety valve V13, the quick exhaust proportional valve V17, and the quick control valve V26 are powered and work under the electronic control of the control unit, the high pressure cut-off valve V11 is closed under the control of the high pressure cut-off control valve V12, the quick hammer pre-valve V27 is opened under the control of the quick control valve V26, the accumulator pressure oil enters the injection rodless chamber through V27, and the oil in the injection rod chamber returns to the oil tank 2 through the quick exhaust proportional valve V17, and the first stage of slow hammer pre-action is performed. The speed value of this stage is in the range of 0.02m / s-0.5m / s.

[0045] 4. A quick hammer pre-action: the quick accumulator A1 supplies oil, the accumulator oil discharge valve V8, the high-pressure cut-off control valve V12, the injection safety valve V13, the quick-discharge proportional valve V17, and the quick control valve V26 are powered and work under the electronic control of the control unit, the high-pressure cut-off valve V11 is closed under the control of the high-pressure cut-off control valve V12, and the quick hammer pre-valve V27 is opened under the control of the quick control valve V26. The hammer pre-speed is controlled by the quick-discharge proportional valve V17 through the analog signal DF1 given by the control unit to achieve single closed-loop control, and the second stage of quick hammer pre-action is carried out. This speed can be adjusted arbitrarily. The speed value of this stage is in the range of 0.5m / s-1.5m / s.

[0046] 5. Second quick hammer pre-action: quick accumulator A1 supplies oil, accumulator oil discharge valve V8, high pressure cut-off control valve V12, injection safety valve V13, quick discharge proportional valve V17, quick control valve V26 are powered and work under the electronic control of the control unit, high pressure cut-off valve V11 is closed under the control of high pressure cut-off control valve V12, quick hammer pre-valve V27 is opened under the control of quick control valve V26, and the pre-hammer speed is controlled by the quick discharge proportional valve V17 through the analog signal DF1 given by the control unit to achieve single closed loop control, and the third stage of quick hammer pre-action is carried out, and this speed can be adjusted arbitrarily. The speed value of this stage is in the range of 1.5m / s-10m / s.

[0047] 6. Boosting action: The fast accumulator A1 supplies oil, the accumulator oil discharge valve V8, the high-pressure cut-off control valve V12, the injection safety valve V13, the quick-discharge proportional valve V17, the active boost return filling valve V20, the boost safety valve V22 and the boost control valve V25 are energized and work under the electronic control of the control unit, the high-pressure cut-off valve V11 is closed under the control of the high-pressure cut-off control valve V12, the boost return oil proportional valve V19 is opened under the control of the analog signal DF4 given by the computer, the boost valve V23 is opened under the control of the boost control valve V25, and the pressure oil in the fast accumulator A1 enters the boost rodless chamber 11 through the boost valve V23. The opening size of the boost return oil proportional valve V19 can be adjusted by the analog signal DF4 given by the control unit to change the back pressure of the boost rod chamber 12, thereby realizing real-time adjustment of the boost pressure and boost time.

[0048] 7. Follow-out action: the fast accumulator A1 supplies oil, the accumulator oil discharge valve V8, the high-pressure cut-off control valve V12, the injection safety valve V13, the quick-discharge proportional valve V17, the active boost return filling valve V20, the boost safety valve V22, and the quick control valve V26 are energized and work under the electronic control of the control unit, the high-pressure cut-off valve V11 is closed under the control of the high-pressure cut-off control valve V12, the quick hammer front valve V27 is opened under the control of the quick control valve V26, the pressure oil of the fast accumulator A1 enters the injection rodless chamber 13 through the quick hammer front valve V27, and the hammer head follows out, and the follow-out speed is controlled by the quick-discharge proportional valve V17 through the analog signal DF1 given by the control unit to achieve single closed-loop control.

[0049] 8. Back-hammer action: Oil pump 3 supplies oil, and the back-hammer control valve V1 and the accumulator oil discharge valve V8 are powered and work under the electronic control of the control unit, and the back-hammer valve V2 is opened under the control of the back-hammer control valve V1. The back-hammer check valve V18 and the boost rodless chamber return oil valve V21 are opened, and the system pressure oil enters the injection rod chamber 14 through the back-hammer valve V2, and the oil in the injection rodless chamber 13 returns to the oil tank through the high-pressure stop valve V11 and the back-hammer return oil valve V4; when the injection piston rod returns to a certain position and hits the boost piston rod, V14 will be passively opened, and the boost rod chamber 12 will absorb oil from the oil tank. When the hammer head is stuck, the active boost return filling valve V20 opens to offset the injection chamber pressure, eliminate part of the resistance of the back-hammer, and facilitate the reset of the hammer head; the oil in the boost rodless chamber 11 returns to the oil tank 2 through the opened check valve V21.

[0050] The patent of the present invention is to perform closed-loop control at the outlet of the boost piston, perform closed-loop control at the boost outlet, and only perform switch control at the inlet. The pressure building time and pressure building pressure are all controlled by the outlet proportional valve for closed-loop control. The accumulator pressure can be stored to a fixed value, and there is no need to adjust the accumulator pressure to control the boost pressure. When the inlet pressure of the boost piston is constant, the boost pressure can still be adjusted arbitrarily within the boost range, that is, the accumulator stored to the maximum working pressure has no effect on the boost pressure. Therefore, we can increase the pre-charged nitrogen pressure, increase the nitrogen pressure margin, and extend the time for the nitrogen pressure caused by leakage to drop to the lower limit, thereby extending the nitrogen replenishment cycle; store the accumulator to the maximum working pressure, and control the boost pressure by controlling the boost piston outlet proportional valve during the process adjustment process, thereby avoiding the problem of releasing or replenishing nitrogen due to pressure adjustment.

[0051] During the boosting process, we can store the accumulator pressure to the maximum working value each time, and control the boost pressure and boost pressure building time in real time through boost outlet closed-loop control. Through practical tests, the fastest pressure building time can be controlled within 30ms without advance amount, and the boost pressure can be adjusted arbitrarily within the boosting range; under the premise of adding advance amount, the pressure building time can be as low as 20ms.

[0052] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present invention are indicated by the claims of the present application.

[0053] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A pressure closed-loop control oil circuit, characterized in that: It includes an injection oil cylinder, an oil tank, an oil pump, a fast accumulator A1, an oil pipeline with a plurality of electric control valves and a control unit. The internal cavity of the injection oil cylinder includes a boost rodless cavity with a boost inlet, a boost rod cavity with a boost outlet, an injection rodless cavity with an injection inlet, and an injection rod cavity with an injection outlet. The electric control valves in the oil pipeline are all electrically connected to the control unit. The oil delivery pipeline includes: an injection control pipeline connecting the fast accumulator A1 and the injection inlet, an injection outlet closed-loop control pipeline connecting the injection outlet and the oil tank, a boost control pipeline connecting the boost inlet and the fast accumulator A1, a boost outlet closed-loop control pipeline connecting the boost outlet and the oil tank, a boost reset filling pipeline connecting the boost outlet and the oil tank, a boost reset oil return pipeline connecting the boost inlet and the oil tank, an accumulator control pipeline connecting the oil pump and the fast accumulator A1, a hammer front control pipeline connecting the oil pump and the injection inlet, and a hammer return pipeline connecting the oil pump and the injection outlet; single closed-loop control of the injection outlet speed is realized by the control unit and the injection outlet closed-loop control pipeline, and the back pressure of the boost rod chamber is changed by adjusting the boost outlet closed-loop control pipeline, thereby realizing single closed-loop control of the boost outlet pressure; The front-hammer control pipeline includes a manual hammer front valve V3, a hammer front control valve V5, a shuttle valve V6, a high-pressure stop valve V11, a high-pressure stop control valve V12, and a pressure-injection safety valve V13; the return-hammer pipeline includes a return-hammer control valve V1, a return-hammer valve V2, a return-hammer oil return valve V4, and a return-hammer check valve V18; one end of the manual hammer front valve V3, one end of the return-hammer valve V2, and one end of the shuttle valve V6 are all connected to the oil pump, one end of the return-hammer oil return valve V4, and one end of the pressure-injection safety valve V13 are all connected to the oil tank, the other end of the manual hammer front valve V3 and the other end of the return-hammer oil return valve V4 are all connected to one end of the high-pressure stop valve V11, and the other end of the high-pressure stop valve V11 is connected to the oil tank. The other end of the shuttle valve V6 is connected to one end of the hammer front control valve V5 and one end of the return hammer control valve V1, one end of the return hammer check valve V18 is connected to the injection outlet, and the other end of the return hammer valve V2 is connected to the other end of the return hammer check valve V18; the hammer front control valve V5, the high-pressure stop control valve V12, the return hammer control valve V1, and the injection safety valve V13 are electrically connected to the control unit respectively, the hammer front control valve V5 controls the switch of the manual hammer front valve V3 and the return hammer oil return valve V4, the high-pressure stop control valve V12 controls the switch of the high-pressure stop valve V11, and the return hammer control valve V1 controls the switch of the return hammer valve V2; The accumulator control pipeline includes an accumulator valve V9, an accumulator control valve V10 and an accumulator oil discharge valve V8, wherein the accumulator control valve V10 and the accumulator oil discharge valve V8 are electrically connected to the control unit respectively, and the accumulator control valve V10 controls the switch of the accumulator valve V9, one end of the accumulator valve V9 is connected to the oil pump, one end of the accumulator oil discharge valve V8 is connected to the oil tank, and the other end of the accumulator valve V9 and the other end of the accumulator oil discharge valve V8 are both connected to the fast accumulator A1; The injection outlet closed-loop control pipeline includes a quick-discharge proportional valve V17 and a pilot accumulator A2. The quick-discharge proportional valve V17 is electrically connected to the control unit. The two ends of the quick-discharge proportional valve V17 are connected to the injection outlet and the oil tank respectively. The pilot accumulator A2 is connected to the outlet of the quick-discharge proportional valve V17. The injection control pipeline includes a fast hammer front valve V27 and a fast control valve V26, wherein the fast control valve V26 is electrically connected to the control unit, one end of the fast control valve V26 is connected to the fast accumulator A1, and the fast control valve V26 controls the switch of the fast hammer front valve V27, and the two ends of the fast hammer front valve V27 are respectively connected to the fast accumulator A1 and the injection inlet; The boost control pipeline includes a boost valve V23, a boost throttle valve V24, and a boost control valve V25. The two ends of the boost valve V23 are respectively connected to the fast accumulator A1 and the boost inlet. The boost control valve V25 is electrically connected to the control unit. The pilot oil circuit of the boost control valve V25 is connected to the fast accumulator A1. The boost control valve V25 controls the switch of the boost valve V23. The boost throttle valve V24 is used to adjust the opening of the boost valve V23. The boost control pipeline also includes a boost safety valve V22, which is electrically connected to the control unit, and the two ends of the boost safety valve V22 are connected to the boost inlet and the fuel tank respectively; The boost outlet closed-loop control pipeline includes a pilot accumulator A3 and a boost oil return proportional valve V19, one end of the boost oil return proportional valve V19 is connected to the boost outlet, the other end of the boost oil return proportional valve V19 is connected to the oil tank, and the boost oil return proportional valve V19 is electrically connected to the control unit; The boost reset filling pipeline includes a boost return filling valve V14 and an active boost return filling valve V20, one end of the boost return filling valve V14 and the active boost return filling valve V20 are connected to the boost outlet, the other end of the boost return filling valve V14 and the active boost return filling valve V20 are connected to the fuel tank, and the active boost return filling valve is electrically connected to the control unit; The boost reset oil return pipeline includes a boost return oil valve V21, one end of the boost return oil valve V21 is connected to the boost inlet, and the other end of the boost return oil valve V21 is connected to the oil tank.

2. The pressure closed-loop control oil circuit according to claim 1, characterized in that: The injection outlet is connected to a pressure sensor R1 and / or a pressure gauge B1; the injection inlet is connected to a pressure sensor R2 and / or a pressure gauge B2; the nitrogen charging port of the fast accumulator A1 is connected to a pressure sensor R3 and / or a pressure gauge B3; the pressure sensors R1, R2 and R3 are all electrically connected to the control unit.

3. The pressure closed-loop control oil circuit according to claim 1, characterized in that: An air filter is also included, and the air filter is in communication with the oil tank.

4. The pressure closed-loop control oil circuit according to claim 1, characterized in that: It also includes an oil filter, one end of which is connected to the fast accumulator A1, and the other end of which is connected to a one-way valve.

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