A dual-accumulator die-casting machine oil circuit system

Abstract

The present invention discloses a double accumulator die-casting machine oil circuit system, belonging to the technical field of die-casting machine control. It includes an injection cylinder and an accumulator, and also includes a boosting accumulator. The boosting accumulator includes a boosting chamber and an annular chamber. The boosting chamber communicates with the rodless chamber of the injection cylinder. The accumulator communicates with the annular chamber of the boosting accumulator through a first servo valve. The annular chamber communicates with the oil tank through a second servo valve. The rod chamber of the injection cylinder communicates with the oil tank through a third servo valve. This solution forms an A-bridge control for the boosting accumulator through the first servo valve and the second servo valve. By controlling the pressure of the annular chamber of the boosting accumulator, the different boosting injection forces of the injection cylinder can be controlled. The third servo valve can regulate the oil discharge of the rod chamber of the injection cylinder, thereby being able to regulate the injection speed of the injection cylinder. This solution only needs to use three servo valves to achieve precise control of the injection speed and injection force.

Description

Technical Field

[0001] The invention relates to a die-casting machine control system, and more particularly to an oil circuit system of a double-accumulator die-casting machine. Background Art

[0002] For the injection system of the die-casting machine, using inlet control during slow movement can avoid starting shock, and using differential control at slow speed can not only reduce the oil consumption of the accumulator, but also reduce the throttling effect of the oil and reduce heat. Using outlet control at high speed can achieve multi-stage adjustable high-speed speed, improve the speed adjustment flexibility of the high-speed stage, and use hydraulic A-bridge control in the boost stage, which can not only achieve high-precision adjustment of the boost injection force, but also achieve stepless adjustment of the boost injection force. The die-casting solution can be customized according to the process. To achieve the above functions, the existing technology needs to be equipped with multiple servo valves, one for inlet control, one for outlet control, and two for boost A-bridge control, at least 4 servo valves.

[0003] For example: Chinese patent announcement number CN118305295A, the invention name is injection control oil circuit, die casting machine and injection control method, the application discloses a die casting machine control oil circuit, including an oil supply system, a cartridge valve and a servo valve, the servo valve is connected to the rod chamber of the injection oil cylinder, the injection chamber and the rod chamber are connected, when the injection control oil circuit is in the outlet throttling state, the cartridge valve is in the full open state, the control device adjusts the opening of the servo valve to control the injection speed; when the injection control oil circuit is in the inlet throttling state, the servo valve is in the full open state, the hydraulic oil adjusts the opening of the cartridge valve to control the injection speed; the scheme adopts the injection control oil circuit to enable the die casting machine to have two speed control modes of outlet throttling and inlet throttling. However, the control accuracy of the injection speed and injection force of the die casting machine is not high, and the flexibility is poor, so the products formed by die casting are prone to defects. Summary of the invention

[0004] The present invention overcomes the problem of low injection control accuracy of existing die-casting machines and provides a dual-accumulator die-casting machine oil circuit system. This solution only requires three servo valves to achieve precise control of injection speed and injection force, thereby improving the injection performance of the die-casting machine.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: a dual accumulator die-casting machine oil circuit system, including an injection oil cylinder and an accumulator, and also including a boost accumulator, the boost accumulator includes a boost chamber and an annular chamber, the boost chamber is connected to the rodless chamber of the injection oil cylinder, the accumulator is connected to the annular chamber of the boost accumulator through the first servo valve, the annular chamber is connected to the oil tank through the second servo valve, and the rod chamber of the injection oil cylinder is connected to the oil tank through the third servo valve. This solution forms an A-bridge control on the boost accumulator through the first servo valve and the second servo valve, and controls the pressure of the annular chamber of the boost accumulator to control the different boost injection forces of the injection oil cylinder; the third servo valve can regulate the oil discharge of the rod chamber of the injection oil cylinder, so as to regulate the fast injection speed of the injection oil cylinder; this solution only needs to use three servo valves to achieve precise control of the injection speed and injection force, and improve the injection performance of the die-casting machine.

[0006] Preferably, a differential circuit is formed between the rod chamber of the injection oil cylinder and the rodless chamber of the injection oil cylinder through the first servo valve. A differential circuit is formed between the rod chamber of the injection oil cylinder and the rodless chamber of the injection oil cylinder, and the oil flow in the differential circuit is controlled by the first servo valve, thereby controlling the slow injection of the injection oil cylinder, so that the start-up impact of the die-casting machine is reduced or even eliminated.

[0007] Preferably, it further includes a valve assembly, which includes a valve V1 and a valve V3. The valve V1 and the valve V3 are arranged on the differential circuit. The valve V1 is arranged on the rod chamber side of the injection oil cylinder, and the valve V3 is arranged on the rodless chamber side of the injection oil cylinder. Valve V1 is a differential valve. During the slow injection stage, valve V1, valve V3 and the first servo valve are energized to form a differential circuit between the rod chamber and the rodless chamber of the injection oil cylinder. The oil in the accumulator enters the rodless chamber of the injection oil cylinder through valves V4 and V3. By adjusting the opening of the first servo valve, the injection speed during the slow injection stage can be adjusted, so that the piston rod in the injection oil cylinder moves smoothly.

[0008] Preferably, the valve assembly further comprises a valve V2, the accumulator is connected in series with the first servo valve and the valve V3 in sequence and forms a first oil circuit with the rodless chamber of the injection oil cylinder, and the accumulator forms a second oil circuit with the rodless chamber of the injection oil cylinder through the valve V2. The first oil circuit is the oil circuit for the accumulator to supply oil to the rodless chamber of the injection oil cylinder through the first servo valve, and the second oil circuit is the main oil circuit for the accumulator to supply oil to the rodless chamber of the injection oil cylinder.

[0009] Preferably, an oil pump is further included, and the valve assembly further includes a valve V15, wherein the oil pump forms a third oil circuit with the annular cavity of the boost accumulator through the valve V15, and the oil pump forms a fourth oil circuit with the boost cavity of the boost accumulator through the valve V15. Energy can be stored in the annular cavity and the boost cavity of the boost accumulator through the third oil circuit and the fourth oil circuit, so as to better control the boost pressure.

[0010] Preferably, the valve assembly further comprises a valve V16, and the oil pump forms a fifth oil circuit with the accumulator through the valve V16. The fifth oil circuit is an oil circuit for the oil pump to store energy for the accumulator, and in subsequent oil circuit control, oil supply control can be performed through the accumulator and the boost accumulator.

[0011] Preferably, the valve assembly further comprises a valve V8, and the accumulator is connected in series with the first servo valve and the valve V8 in sequence to form a sixth oil circuit with the annular cavity of the boost accumulator. The oil in the accumulator can enter the boost accumulator through the sixth oil circuit, providing sufficient oil for the boost control of the boost accumulator to achieve boost control.

[0012] Preferably, the valve assembly further comprises a valve V5, the annular cavity of the boost accumulator is connected to the second servo valve and forms a seventh oil circuit with the oil tank, and the boost chamber of the boost accumulator is connected to the valve V5 and forms an eighth oil circuit with the rodless cavity of the injection oil cylinder. The eighth oil circuit boosts the injection oil cylinder through the boost accumulator, and the opening of the second servo valve in the seventh oil circuit can be adjusted, so that the boost effect of the eighth oil circuit on the injection oil cylinder can be regulated, and the precision of the injection force can be adjusted.

[0013] Preferably, the valve assembly further includes a valve V13, and the oil pump sequentially connects the valve V13 and the valve V3 to form a ninth oil circuit with the rodless chamber of the injection oil cylinder. The ninth oil circuit is supplied with oil by the oil pump, and the oil is passed into the rodless chamber of the injection oil cylinder through the valves V13 and V3, and the oil in the rod chamber of the injection oil cylinder flows back to the oil tank through the third servo valve, so that the die-casting machine can be manually operated before starting.

[0014] Preferably, the valve assembly further comprises valve V14 and valve V12, the oil pump connects the valve V12 with the rod chamber of the injection oil cylinder to form a tenth oil circuit, the injection oil cylinder is sequentially connected in series with the valve V3 and valve V14 and forms an eleventh oil circuit with the oil tank. The tenth oil circuit passes the oil in the oil pump into the rod chamber of the injection oil cylinder, and the eleventh oil circuit passes the oil in the rodless chamber of the injection oil cylinder into the oil tank, so that the die casting machine can be operated manually or after hammering.

[0015] Compared with the prior art, the beneficial effects of the present invention are: (1) only three servo valves are needed to achieve precise control of the injection speed and injection force, thereby improving the injection performance of the die-casting machine; (2) the start-up impact of the die-casting machine is small and the movement is smooth; (3) in the high-speed stage, the use of outlet control can achieve multi-stage adjustable high-speed speed, thereby improving the speed adjustment flexibility in the high-speed stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the oil system of the present invention.

[0017] Figure 2 It is a schematic diagram of the oil circuit in the pre-stage of the manual hammer of the present invention.

[0018] Figure 3 It is a schematic diagram of the oil circuit in the manual hammering and automatic return hammering stages of the present invention.

[0019] Figure 4 It is a schematic diagram of the oil circuit in the injection energy storage stage of the present invention.

[0020] Figure 5 It is a schematic diagram of the oil circuit in the boost and energy storage stage of the present invention.

[0021] Figure 6 It is a schematic diagram of the oil circuit in the slow injection stage of the present invention.

[0022] Figure 7 It is a schematic diagram of the oil circuits in the rapid injection stage and the braking stage of the present invention.

[0023] Figure 8 It is a schematic diagram of the oil circuit in the boost stage of the present invention.

[0024] Fig. 9 This is a schematic diagram of the oil circuit in the tracking stage of the present invention.

[0025] In the figure: 1. Injection cylinder, 2. Boosting accumulator, 3. Accumulator. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] Example 1: Figures 1 to 9A dual-accumulator die-casting machine oil circuit system shown includes an injection oil cylinder 1, an accumulator 3 and a boost accumulator 2. The accumulator 3 and the boost accumulator 2 are connected to the oil circuit on the rodless chamber inlet side of the injection oil cylinder 1 to control the inlet of the injection oil cylinder 1; the accumulator 3 and the injection accumulator 2 can store hydraulic energy and perform oil control on the injection oil cylinder 1. Specifically, the boost accumulator 2 includes a boost cylinder, the interior of the boost cylinder is a convex cavity, a piston rod is slidably arranged inside the boost cylinder, the rod end of the piston rod is away from the piston side and the convex end of the boost cylinder forms a boost chamber, and the piston of the piston rod is close to the rod end side and the boost cylinder forms an annular cavity. The injection oil circuit system of the die-casting machine also includes an oil pump and an oil tank. The oil pump can supply oil to the entire die-casting machine injection oil circuit system, and the oil tank is the oil return structure of the entire die-casting machine injection oil circuit system.

[0028] As shown in the figure, the die-casting machine injection oil circuit system includes 16 hydraulic valves, namely valve V1 to valve V16. Among them, valve V1 is a differential valve, valve V2 is a large-diameter active cartridge valve, valve V3 is a common cartridge valve, valve V3 has the characteristics of high pressure resistance, valve V4 is the first servo valve, and the opening of valve V4 can be adjusted, valve V5 is the oil inlet valve for supplying oil to the rodless chamber of injection cylinder 1 in the booster oil circuit control, valve V6, valve V10 and valve V11 are safety valves, valve V6, valve V10 Valve V11 is a normally open hydraulic valve, valve V7 is the second servo valve, the opening of valve V7 can be adjusted, valve V8 is the oil inlet valve for accumulator 3 to supply oil to the annular cavity of boosting accumulator 2; valve V9 is the third servo valve, the opening of valve V9 can be adjusted, valve V12 is the oil inlet valve for the oil pump to supply oil to the rod cavity of injection cylinder 1; valve V13 is the oil inlet valve for the oil pump to supply oil to the rodless cavity of injection cylinder 1, valve V14 is the oil return valve for returning the oil in the rodless cavity of injection cylinder 1 to the oil tank; valve V15 is the oil inlet valve for the oil pump to supply oil to the boosting cavity and annular cavity of the boosting accumulator 2; valve V16 is the oil inlet valve for the oil pump to supply oil to the accumulator 3. The first servo valve and the second servo valve form an A-bridge control on the boost accumulator 2, and the pressure of the annular cavity of the boost accumulator 2 is controlled to control the different boost injection forces of the injection cylinder 1; the third servo valve can regulate the oil discharge of the rod cavity of the injection cylinder 1, so as to regulate the injection speed of the injection cylinder 1; this scheme only needs to use three servo valves to achieve precise control of the injection speed and injection force of the die-casting machine, and improve the injection performance of the die-casting machine. Among them, valve V6, valve V10 and valve V11 will continue to be energized and in a closed state in the non-depressurized state, which can protect the oil circuit system and facilitate the oil discharge and maintenance of the oil circuit system.

[0029] The injection oil circuit system of the die-casting machine also includes multiple oil circuits. Specifically, a differential circuit is formed between the rodless chamber of the injection oil cylinder 1 and the rod chamber of the injection oil cylinder 1. The differential circuit is supplied with oil by the accumulator 3. The valve V1, valve V4 and valve V3 are connected in series in sequence from the rod chamber of the injection oil cylinder 1 to form a differential circuit with the rodless chamber of the injection oil cylinder 1. The differential circuit can slowly start the piston rod in the injection oil cylinder 1 during the slow injection stage to reduce the starting impact. The accumulator 3 is connected in series with the first servo valve (valve V4) and valve V3 in sequence to form a first oil circuit with the rodless chamber of the injection oil cylinder 1. The first oil circuit is part of the differential circuit, and the amount of oil entering the injection oil cylinder 1 from the accumulator 3 can be adjusted by adjusting the opening of the first servo valve. The accumulator 3 is connected to the valve V2 and forms the second oil circuit with the rodless chamber of the injection oil cylinder 1. The second oil circuit is the main oil circuit for the accumulator 3 to supply oil to the rodless chamber of the injection oil cylinder 1. The diameter of the valve V2 is relatively large. The oil pump is connected to the valve V15 and forms the third oil circuit with the annular chamber of the boost accumulator 2. The oil pump is connected to the valve V15 and forms the fourth oil circuit with the boost chamber of the boost accumulator 2. The third and fourth oil circuits are the oil circuits for the oil pump to supply oil to the boost accumulator 2, and the pressure of the boost accumulator 2 is stored. It can be understood that the third and fourth oil circuits are parallel oil circuits. The oil pump is connected to the valve V16 and forms the fifth oil circuit with the accumulator 3. The fifth oil circuit is the energy storage oil circuit for the oil pump to supply oil to the accumulator 3. The accumulator 3 is connected in series with the first servo valve (valve V4) and valve V8 in sequence and forms the sixth oil circuit with the annular cavity of the boost accumulator 2. The sixth oil circuit is the oil circuit for the accumulator 3 to supply oil to the boost accumulator 2, so that the boost accumulator 3 can provide sufficient oil pressure. The annular cavity of the boost accumulator 3 is connected to the second servo valve (valve V7) and the oil tank to form the seventh oil circuit. The seventh oil circuit is the return oil circuit of the boost chamber of the boost accumulator 2. Since the opening of the second servo valve can be adjusted, it is also the oil circuit for regulating the injection force of the injection cylinder 1 during the boost control. The boost chamber of the accumulator 3 is connected to the valve V5 and then forms the eighth oil circuit with the rodless cavity of the injection cylinder 1. The eighth oil circuit is the boost oil circuit, and the boost effect is achieved on the injection cylinder 1 through the boost accumulator 2. The oil pump is connected in series with valve V13 and valve V3 in sequence and forms the ninth oil circuit with the rodless chamber of the injection oil cylinder. In addition, the rod chamber of the injection oil cylinder 1 is connected to the third servo valve (valve V9) and the oil tank to form the main oil return circuit. The ninth oil circuit and the main oil return circuit can make the piston rod in the injection oil cylinder 1 slowly extend to perform manual pre-hammer operation. The oil pump is connected to valve V12 and then forms the tenth oil circuit with the rod chamber of the injection oil cylinder. The tenth oil circuit is the oil circuit for the oil pump to supply oil to the rod chamber of the injection oil cylinder 1. The rodless chamber of the injection oil cylinder 1 is connected in series with valve V3 and valve V14 in sequence and then forms the eleventh oil circuit with the oil tank. The eleventh oil circuit is the oil circuit for the rodless chamber of the injection oil cylinder 1 to return oil. Through the tenth oil circuit and the eleventh oil circuit, the piston rod in the injection oil cylinder 1 can be slowly retracted to perform manual or automatic return hammer operation.

[0030] It can be understood that only one oil port is provided on the rod chamber and the rodless chamber of the injection cylinder 1, and only one oil port is provided on the boosting chamber and the annular chamber of the boosting accumulator 2. Therefore, when the above-mentioned oil circuits are connected to the corresponding oil cylinders, the oil pipes merge to form a main oil pipe and then are connected to the oil port on the injection cylinder 1 or the boosting accumulator 2.

[0031] In this scheme, the working process of the die-casting machine includes the manual hammer pre-stage, the manual hammer post-stage, the injection energy storage stage, the boost energy storage stage, the slow injection stage, the fast injection stage, the braking stage, the boost stage, the pressure relief stage, the tracking stage, and the automatic return hammer stage. The following is an explanation with the help of the diagram.

[0032] Manual hammer pre-stage, such as Figure 2 As shown, valve V13, valve V3 and valve V9 are energized and in the open state, and the injection oil cylinder 1 supplies oil to the rodless chamber through the ninth oil circuit, and then returns oil through the main oil return circuit. It can be understood that in the pre-manual hammer stage, the oil pressure pumped into the rodless chamber side of the injection oil cylinder 1 by the oil pump is relatively large. In order to make the piston rod of the injection oil cylinder 1 move slowly and smoothly, the opening of the third servo valve (valve V9) can be adjusted to decrease at this time, which is conducive to pressurizing the rod chamber end of the injection oil cylinder 1, so that the back pressure of the piston rod of the injection oil cylinder 1 is increased, and the piston rod moves more smoothly.

[0033] After the manual hammer stage, such as Figure 3 As shown, the injection oil cylinder 1 supplies oil to the rod chamber through the tenth oil circuit, and then returns oil through the eleventh oil circuit. At this time, valve V12 is energized, and the oil from the oil pump enters the rod chamber of the injection oil cylinder 1 through valve V12. Valve V3 and valve V14 are energized, and the oil in the rodless chamber of the injection oil cylinder 1 returns to the oil tank. When the oil in the oil pump enters the rod chamber of the injection oil cylinder 1, a large oil pressure will be generated in the rod chamber of the injection oil cylinder 1, while the oil pressure on the rodless chamber side of the injection oil cylinder 1 is small. Therefore, the staff can easily perform the manual post-hammer operation, that is, the return hammer operation, so that the piston rod in the injection oil cylinder 1 is retracted.

[0034] The manual hammer pre-operation and the manual hammer post-operation can detect whether the movement of the piston rod in the injection cylinder 1 is subject to a large resistance and whether its movement stroke is smooth.

[0035] Injection energy storage stage, such as Figure 4 As shown, the injection stage is controlled by the fifth oil circuit. When the injection energy storage stage is in progress, the valve V16 is energized and in an open state. At this time, the oil pumped by the oil pump enters the accumulator 3 through the valve V16 and stores hydraulic energy in the accumulator 3. In the subsequent working process, the oil pressure of the system is provided by the accumulator 3 to improve the control efficiency and response speed of the system.

[0036] During the boost energy storage phase, Figure 5As shown, the boosting energy storage stage is controlled by the third oil circuit and the fourth oil circuit. In the boosting energy storage stage, the valve V15 is energized and in the open state. At this time, the oil pumped in by the oil pump passes through the valve V15 and then flows into the annular cavity and the boosting cavity of the boosting accumulator 2 respectively; that is, after the oil passes through the valve V15, the oil circuit is branched to form the third oil circuit and the fourth oil circuit, so that the oil pressure of the third oil circuit and the fourth oil circuit is the same, and the oil pressure entering the annular cavity of the boosting accumulator 2 is the same as the oil pressure entering the boosting cavity of the boosting accumulator 2, and the oil pressure in the two cavities drives the piston rod in the boosting oil cylinder to move, so that pressure storage can be formed in the boosting accumulator 2. When the oil pressure storage is completed, the valve V15 is closed to maintain sufficient pressure in the boosting accumulator 2.

[0037] Slow injection stage, such as Figure 6 As shown, the slow-speed injection stage is controlled by the differential circuit and the first oil circuit. In the slow-speed injection stage, valves V3, V4 and V1 are energized and in the open state. At this time, since the oil pressure energy has been stored in the accumulator 3 in the injection energy storage stage, the slow start of the injection cylinder 1 can be controlled by the oil supply of the accumulator 3; the oil in the accumulator 3 enters the rodless cavity of the injection cylinder 1 through the first oil circuit, and on both sides of the piston rod in the injection cylinder 1, the oil action area in the rod cavity is smaller than the oil action area in the rodless cavity. Therefore, in the slow-speed injection stage, the oil pressure in the rodless cavity of the injection cylinder 1 is greater than the oil pressure in the rod cavity of the injection cylinder 1, and the piston rod of the injection cylinder 1 extends, and the first servo valve (valve V4) is a small-diameter port. By adjusting the opening of the first servo valve, the oil pressure difference between the rodless chamber of the injection oil cylinder 1 and the rod chamber of the injection oil cylinder 1 can be controlled to decrease, and the pressure can be built up at the same time to avoid the imbalance of the pressure in the two chambers, thereby realizing the slow extension of the piston rod of the injection oil cylinder 1. In this way, during the startup process of the die-casting machine, the startup impact is smaller and more stable, avoiding the entrainment of the metal liquid in the feeding barrel and preventing defects such as bubbles in the final die-casting product; in addition, it can also reduce the heat generated by oil throttling and reduce the oil consumption in the slow injection stage.

[0038] Rapid injection stage, such as Figure 7As shown, the rapid injection stage is controlled by the second oil circuit, the sixth oil circuit and the main oil return circuit. In the rapid injection stage, the oil pressure is still provided by the accumulator 3. At this time, valve V1, valve V3 and the second servo valve (valve V7) are not energized and are in a closed state. Valve V2, valve V4, valve V5, valve V8 and the third servo valve (valve V9) are energized. At this time, the oil inlet of the injection cylinder 1 is completely controlled by valve V2 and is in a fully open state; specifically, through the second oil circuit, the oil in the accumulator 3 enters the rodless cavity of the injection cylinder 1 through valve V2, and then through the main oil return circuit, the oil pressure in the rod cavity of the injection cylinder 1 enters the oil tank after passing through the third servo valve. In order to achieve the rapid movement of the piston rod of the injection cylinder 1, the opening of the third servo valve can be adjusted to be larger at this time to reduce the resistance on the rod cavity side of the injection cylinder 1 and achieve the rapid injection effect of the injection cylinder 1. In addition, through the sixth oil circuit, a part of the oil in the accumulator 3 passes through the first servo (valve V4), and then passes through the valve V8 to enter the annular cavity of the boost accumulator 2, and is ready to start pressurization in the boost accumulator 2. And because the second servo valve (valve V7) is in a closed state, the oil in the annular cavity of the boost accumulator 2 cannot be discharged, thereby ensuring that the oil in the enhancement cavity of the boost accumulator 2 will not enter the rodless cavity of the injection cylinder 1 through the valve V5. At this time, the valve V5 is opened, so that the valve V5 is opened in advance. When entering the boosting stage, only the valve V7 needs to be opened to directly enter the boosting, thereby realizing rapid pressure build-up and boosting, and improving the response speed.

[0039] Braking phase, such as Figure 7 As shown, the control oil circuit in the braking stage is the same as the control oil circuit in the fast injection stage. At this time, the oil pressure is still provided by the accumulator 3, the valve V1, the valve V3 and the second servo valve (valve V7) are not energized and are in a closed state, the valve V2, the valve V4, the valve V5, the valve V8 and the third servo valve (valve V9) are energized, and the oil inlet of the injection cylinder 1 is completely controlled by the valve V2 and is in a fully open state; in order to achieve the deceleration braking of the piston rod of the injection cylinder 1, at this time, it is only necessary to adjust the opening of the third servo valve (valve V9) to adjust the movement speed of the piston rod. Specifically, by reducing the opening of the third servo valve, the resistance at one end of the rod cavity of the injection cylinder 1 increases, so that the speed of the piston rod of the injection cylinder 1 gradually decreases and stops moving.

[0040] The boost phase, such as Figure 8As shown, the boosting stage is controlled by the sixth oil circuit, the seventh oil circuit and the eighth oil circuit. In the boosting control stage, valves V4, V5, V7 and V8 are energized and are in the open state, that is, from the braking stage to the boosting stage, the third servo valve (valve V9) is closed and the second servo valve (valve V7) is opened. Valve V5 has been opened in advance during the fast injection stage. At this time, after the second servo valve (valve V7) is opened, the oil in the accumulator 3 flows to the valve V8 through the valve V4, and then enters the annular cavity position of the boosting accumulator 2. The oil in the annular cavity will be discharged through the second servo valve (valve V7) (because the second servo valve is connected to the oil tank, the oil pressure here is relatively small), and the oil pressure in the annular cavity is reduced, so that the piston rod in the boosting accumulator 2 can start to move, so that the oil in the boosting cavity starts to be discharged, and the oil in the boosting cavity passes through the valve V5 and enters the rodless cavity of the injection cylinder 1, and the injection cylinder 1 is pressurized by the boosting accumulator 2. Among them, the opening of the first servo valve (valve V4) can be adjusted, and the opening of the second servo valve (valve V7) can be adjusted. The first servo valve and the second servo valve form an A-bridge control on the annular cavity of the boost accumulator 2. By controlling the pressure of the annular cavity in the boost accumulator 2, different boost injection forces can be controlled. Specifically, in order to reduce the injection force, the opening of the first servo valve can be reduced or the opening of the second servo valve can be reduced. In order to increase the injection force, the opening of the first servo valve can be increased or the opening of the second servo valve can be increased.

[0041] Pressure relief stage, such as Figure 8 As shown, the control oil circuit in the pressure relief stage is the same as the control oil circuit in the pressure increase stage, except that the oil inlet direction is opposite. At this time, it is only necessary to reduce the pressure in the rodless chamber of the injection cylinder 1, so that the overall pressure in the injection cylinder 1 is reduced to prevent the tracking from being out of control due to excessive oil compression during the tracking stage.

[0042] Tracking stage: During the die-casting machine's die-opening operation, the piston rod of the injection oil cylinder 1 slowly extends out along with the die-opening process. The tracking stage is controlled by the first oil circuit and the main return oil circuit. At this time, valves V3, V4 and V9 are energized, and the oil in the accumulator 3 passes through the first servo valve (valve V4) and enters the rodless chamber of the injection oil cylinder 1. Then, the oil in the rod chamber of the injection oil cylinder 1 flows back to the oil tank through the third servo valve (valve V9). By controlling the opening of valves V4 and V9, the speed of the die-casting machine during tracking can be controlled. Specifically, after controlling the first servo valve and the third servo valve to the appropriate opening, the oil pressure in the rodless chamber of the injection oil cylinder 1 is slightly greater than the oil pressure in the rod chamber of the injection oil cylinder 1. In this way, during the die-opening operation, the piston rod of the injection oil cylinder 1 can extend along with the mold while maintaining a relatively stable and slow speed.

[0043] In the automatic hammer return stage, after the die casting machine is finished working, the mold, the piston rod in the injection cylinder 1 and other structures need to be reset to realize the hammer return operation. Figure 3 As shown, the oil circuit control in the automatic return hammer stage is the same as the oil circuit control in the manual hammer pre-stage. The injection oil cylinder 1 supplies oil to the rod chamber through the tenth oil circuit, and then returns oil through the eleventh oil circuit. At this time, valve V12 is energized, and the oil from the oil pump enters the rod chamber of the injection oil cylinder 1 through valve V12. Valve V3 and valve V14 are energized, and the oil in the rodless chamber of the injection oil cylinder 1 returns to the oil tank. When the oil in the oil pump enters the rod chamber of the injection oil cylinder 1, a large oil pressure will be generated in the rod chamber of the injection oil cylinder 1, while the oil pressure on the rodless chamber side of the injection oil cylinder 1 is small. Therefore, the die-casting machine can perform the return hammer operation by itself, so that the piston rod in the injection oil cylinder 1 is retracted.

Claims

1. A dual accumulator die casting machine oil circuit system, comprising an injection oil cylinder and an accumulator, characterized in that: It also includes a boost accumulator, which includes a boost chamber and an annular chamber, the boost chamber is connected to the rodless chamber of the injection cylinder, the accumulator is connected to the annular chamber of the boost accumulator through a first servo valve, the annular chamber is connected to the oil tank through a second servo valve, and the rod chamber of the injection cylinder is connected to the oil tank through a third servo valve; it also includes a valve assembly, which includes a valve V8 and a valve V5, the accumulator is connected in series with the first servo valve and the valve V8 in sequence, and forms a sixth oil circuit with the annular chamber of the boost accumulator; the annular chamber of the boost accumulator is connected to the second servo valve and forms a seventh oil circuit with the oil tank, the boost chamber of the boost accumulator is connected to the valve V5 and forms an eighth oil circuit with the rodless chamber of the injection cylinder; the first servo valve and the second servo valve form an A-bridge control on the annular chamber of the boost accumulator; valve V5 is an oil inlet valve for supplying oil to the rodless chamber of the injection cylinder in the boost oil circuit control, and valve V8 is an oil inlet valve for supplying oil to the annular chamber of the boost accumulator by the accumulator.

2. The dual accumulator die casting machine oil circuit system according to claim 1, characterized in that: A differential circuit is formed between the rod chamber of the injection oil cylinder and the rodless chamber of the injection oil cylinder through the first servo valve; and the oil in the accumulator enters into the rodless chamber of the injection oil cylinder.

3. The dual accumulator die casting machine oil circuit system according to claim 2, characterized in that: The valve assembly includes a valve V1 and a valve V3, wherein the valve V1 is a differential valve and the valve V3 is a cartridge valve. The valve V1 and the valve V3 are arranged on the differential circuit, the valve V1 is arranged on the rod chamber side of the injection cylinder, and the valve V3 is arranged on the rodless chamber side of the injection cylinder.

4. The dual accumulator die casting machine oil circuit system according to claim 3, characterized in that: The valve assembly also includes a valve V2, which is an active cartridge valve. The accumulator is connected in series with the first servo valve and the valve V3 in sequence and forms a first oil circuit with the rodless chamber of the injection cylinder. The accumulator forms a second oil circuit with the rodless chamber of the injection cylinder through the valve V2.

5. A dual accumulator die casting machine oil circuit system according to claim 3 or 4, characterized in that: It also includes an oil pump, and the valve assembly also includes a valve V15, which is an oil inlet valve for the oil pump to supply oil to the boosting chamber and the annular cavity of the boosting accumulator. The oil pump forms a third oil circuit with the annular cavity of the boosting accumulator through the valve V15, and the oil pump forms a fourth oil circuit with the boosting chamber of the boosting accumulator through the valve V15.

6. The dual accumulator die casting machine oil circuit system according to claim 5, characterized in that: The valve assembly further includes a valve V16, through which the oil pump forms a fifth oil circuit with the accumulator, and the valve V16 is an oil inlet valve for the oil pump to supply oil to the accumulator.

7. The dual accumulator die casting machine oil circuit system according to claim 4, characterized in that: During the rapid injection stage, the oil in the accumulator enters the rodless chamber of the injection cylinder through the second oil circuit and through the valve V2; through the sixth oil circuit, the oil in the accumulator also enters the annular chamber of the booster accumulator through the first servo.

8. A dual accumulator die casting machine oil circuit system according to claim 4 or 7, characterized in that: During the pressurization stage, the third servo valve is closed and the second servo valve is opened. The oil in the accumulator enters the annular cavity position of the pressurized accumulator, the oil in the annular cavity is discharged through the second servo valve, and the oil in the pressurized cavity enters the rodless cavity of the injection cylinder.

9. The dual accumulator die casting machine oil circuit system according to claim 5, characterized in that: The valve assembly further includes a valve V13, which is an oil inlet valve for the oil pump to supply oil to the rodless chamber of the injection cylinder. The oil pump sequentially connects the valve V13 and the valve V3 to form a ninth oil circuit with the rodless chamber of the injection cylinder.

10. The dual accumulator die casting machine oil circuit system according to claim 9, characterized in that: The valve assembly also includes valve V14 and valve V12. Valve V12 is an oil inlet valve for the oil pump to supply oil to the rod chamber of the injection cylinder. Valve V14 is an oil return valve for returning the oil in the rodless chamber of the injection cylinder to the oil tank. The oil pump connects the valve V12 with the rod chamber of the injection cylinder to form the tenth oil circuit. The injection cylinder is connected in series with valve V3 and valve V14 in sequence to form the eleventh oil circuit with the oil tank.

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