A hydraulic system applied to the quick opening and closing mold of an injection molding machine

Abstract

This invention relates to the field of injection molding equipment, and particularly to a hydraulic system for rapid mold opening and closing in injection molding machines. It includes a mold opening and closing cylinder, an oil pump, and a main oil tank. The oil pump is connected to a motor. The mold opening and closing cylinder, oil pump, and main oil tank are sequentially connected by oil pipes. A pressure boosting device, a steering device, and a flow-blocking device are provided between the mold opening and closing cylinder and the oil pump. Both the mold opening and closing cylinder and the oil pump are connected to the steering device via oil pipes. The flow-blocking device is connected to the steering device at one end and to the main oil tank at the other end via an oil pipe. The pressure boosting device is connected to the oil pipe between the mold opening and closing cylinder and the steering device at one end and to the oil pipe between the flow-blocking device and the steering device at the other end. The hydraulic medium, through the coordinated opening and closing of the pressure boosting device, the steering device, and the flow-blocking device, enables rapid starting and resetting of the mold opening and closing cylinder.

Description

[Technical Field]

[0001] This invention relates to the field of injection molding equipment, and in particular to a hydraulic system for rapid mold opening and closing in injection molding machines. [Background Technology]

[0002] Injection molding machines mainly consist of mold clamping components, injection components, hydraulic transmission, and electrical control systems, with the hydraulic system, as the power source, being a crucial component. With societal development, the demand for injection-molded products is increasing, making the processing efficiency of injection molding machines particularly important. In the production cycle of an injection molding machine, the mold opening and closing process is a crucial part. During this process, the rodless chamber of the mold opening and closing cylinder, due to its large area, requires a significant hydraulic oil flow to achieve a certain speed. Simply increasing the speed of the rodless chamber by enlarging the oil pump and motor would have a substantial impact on production costs, resulting in unnecessary waste. Conversely, attempting to increase speed by reducing the cylinder diameter might lead to insufficient thrust, and even if sufficient thrust is achieved, the cylinder's lifespan would be affected. Furthermore, when the rod chamber speed is high, the return flow of the rodless chamber is much greater than the inlet flow of the rod chamber. If the rated flow rate of the control valve is set to the system's maximum flow rate, the control valve will be unable to meet the actual demand during the return flow of the rodless chamber. This will not only cause back pressure in the rodless chamber, affecting the feed speed of the rod chamber, but also result in energy loss in the hydraulic system. [Summary of the Invention]

[0003] The purpose of this invention is to address the deficiencies and shortcomings of the prior art by providing a hydraulic system for rapid mold opening and closing of injection molding machines. This system uses a hydraulic control system to increase the flow rate of oil in the rodless chamber of the mold opening and closing cylinder, thereby improving the overall speed of mold opening and closing.

[0004] To address the above problems, the present invention adopts the following technical solution:

[0005] A hydraulic system for rapid mold opening and closing in an injection molding machine includes a mold opening and closing cylinder, an oil pump, and a main oil tank. The oil pump is connected to a motor. The mold opening and closing cylinder, oil pump, and main oil tank are sequentially connected by oil pipes. A booster device, a steering device, and a flow-blocking device are provided between the mold opening and closing cylinder and the oil pump. Both the mold opening and closing cylinder and the oil pump are connected to the steering device via oil pipes. The flow-blocking device is connected to the steering device at one end and to the main oil tank at the other end via an oil pipe. The booster device is connected to the oil pipe between the mold opening and closing cylinder and the steering device at one end and to the oil pipe between the flow-blocking device and the steering device at the other end via an oil pipe. Hydraulic medium is contained in the oil pipes. The hydraulic medium, through the coordinated opening and closing of the booster device, the steering device, and the flow-blocking device, enables rapid start-up and reset of the mold opening and closing cylinder.

[0006] Preferably, the steering device includes an electro-hydraulic directional valve, which is provided with port P, port B, port T and port A. Port P is connected to an oil pump through an oil pipe, port B is connected to the rod chamber B1 of the mold opening and closing cylinder through an oil pipe, port T is connected to a flow-blocking device through an oil pipe, and port A is connected to the rodless chamber A1 of the mold opening and closing cylinder through an oil pipe. The electro-hydraulic directional valve can connect port A and port P, port T and port B, or connect port A and port T, port P and port B.

[0007] Preferably, the pressurization device includes a first cartridge valve, a hydraulically controlled check valve, and an auxiliary oil tank. The first cartridge valve is provided with oil port X, oil port A3, and oil port B3. Oil port X is connected to the hydraulically controlled check valve through a first return oil branch pipe. The hydraulically controlled check valve is connected to the auxiliary oil tank. Oil port B3 is connected to the oil pipe between oil port A and the rodless cavity A1 of the mold opening and closing cylinder through a first branch pipe 109. A first branch pipe is connected between the first branch pipe 109 and the first return oil branch pipe. Oil port A3 is connected to the oil pipe between oil port T and the flow-blocking device through a second branch pipe.

[0008] Preferably, the flow-blocking device includes a second cartridge valve and a second solenoid directional valve. The second cartridge valve has port x, port A2 and port B2. The second solenoid directional valve has port P1, port B1, port T1 and port A1. Port B1 is connected to the oil pipe between port T and port A2 through a first flow-blocking branch pipe. Port x, port P1 and the first flow-blocking branch pipe are interconnected through a first tee pipe. Port B2 is connected to the main oil tank through an oil outlet pipe. The oil outlet pipe is connected to port T1 through an oil outlet branch pipe. A return oil pipe is provided between port A1 and the oil outlet branch pipe.

[0009] Preferably, the electro-hydraulic directional valve is a three-position four-way electro-hydraulic directional valve.

[0010] Preferably, the second electromagnetic directional valve is a two-position four-way electromagnetic directional valve.

[0011] Preferably, the hydraulic control check valve is a two-position two-way hydraulic control check valve.

[0012] Preferably, an overflow valve and a pressure sensor are also provided between the oil pump and the steering device.

[0013] The beneficial effects of the hydraulic system for rapid mold opening and closing in injection molding machines according to the present invention are as follows:

[0014] This invention discloses a hydraulic system for rapid mold opening and closing in injection molding machines. When oil enters the rodless chamber A1 of the hydraulic cylinder, a differential circuit is formed through a flow-blocking device, a pressure boosting device, and a steering device. This allows the hydraulic oil from the rod chamber to flow to the rodless chamber, thereby increasing the oil flow rate in the rodless chamber and thus increasing the speed. When oil enters the rod chamber B1 of the hydraulic cylinder, a rapid oil return circuit is formed through the flow-blocking device, the pressure boosting device, and the steering device. This allows the hydraulic oil from the rodless chamber to return simultaneously through the first cartridge valve in the steering device and the pressure boosting device. This avoids resistance when the oil flows from port A to port T due to the oil return flow rate of the rodless chamber being greater than the rated flow rate of the steering device, which would affect the common advance speed of the rod chamber.

[0015] The following will further explain the concept, specific structure and effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of the present invention. [Attached Image Description]

[0016] Figure 1 This is a schematic diagram of the structure of the present invention;

[0017] Oil pump 2; main oil tank 90; motor 3; electro-hydraulic directional valve 8; oil port P; oil port B; oil port T; oil port A; rod chamber B1; rodless chamber A1; first cartridge valve 10; hydraulically controlled check valve 9; auxiliary oil tank 99; oil port X; oil port A3; oil port B3; first return branch pipe 101; first branch pipe 109; first branch pipe 102; second branch pipe 103; second cartridge valve 6; second solenoid directional valve 7; oil port x; oil port A2; oil port B2; oil port P3; oil port B3; oil port T3; oil port A3; first flow-blocking branch pipe 104; first tee pipe 105; oil outlet pipe 106; oil outlet branch pipe 107; return pipe 108; overflow valve 4; pressure sensor 5.

Detailed Implementation Methods

[0018] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," and "right," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" or "several" means two or more.

[0020] Please see Figure 1 , Figure 1 This discloses an optimal implementation of a hydraulic system for rapid mold opening and closing in injection molding machines:

[0021] A hydraulic system for rapid mold opening and closing in an injection molding machine includes a mold opening and closing cylinder, an oil pump, and a main oil tank. The oil pump is connected to a motor. The mold opening and closing cylinder, oil pump, and main oil tank are sequentially connected by oil pipes. A booster device, a steering device, and a flow-blocking device are provided between the mold opening and closing cylinder and the oil pump. Both the mold opening and closing cylinder and the oil pump are connected to the steering device via oil pipes. The flow-blocking device is connected to the steering device at one end and to the main oil tank at the other end via an oil pipe. The booster device is connected to the oil pipe between the mold opening and closing cylinder and the steering device at one end and to the oil pipe between the flow-blocking device and the steering device at the other end. Hydraulic medium is contained in the oil pipes. The preferred implementation of this embodiment is as follows: the hydraulic medium is hydraulic oil, and the mold opening and closing cylinder is a hydraulic cylinder; the steering device includes an electro-hydraulic directional valve, which is provided with port P, port B, port T, and port A. Port P is connected to the oil pump through an oil pipe, port B is connected to the rod chamber B1 of the mold opening and closing cylinder through an oil pipe, port T is connected to the flow-blocking device through an oil pipe, and port A is connected to the rodless chamber A1 of the mold opening and closing cylinder through an oil pipe. The electro-hydraulic directional valve can connect port A and port P, port T and port B, or connect port A and port T, and port P and port B. The electro-hydraulic directional valve is a three-position four-way electro-hydraulic directional valve, which is an O-type directional valve. The left and right sides of the electro-hydraulic directional valve are respectively equipped with solenoid pilot valve 1YA and solenoid pilot valve 2YA. When solenoid pilot valve 2YA is energized, the valve core of the electro-hydraulic directional valve moves to the left, allowing hydraulic oil to flow from port P to port A of the electro-hydraulic directional valve 8. Port A of the electro-hydraulic directional valve is connected to the rodless chamber A1 of the hydraulic cylinder, causing the piston rod to move to the right, and the injection molding machine performs the mold opening action. If solenoid pilot valve 1YA is energized, the valve core of the electro-hydraulic directional valve 8 moves to the right, allowing hydraulic oil to flow from port P to port B of the electro-hydraulic directional valve 8. Port B of the electro-hydraulic directional valve is connected to the rodless chamber B1 of the hydraulic cylinder, causing the piston rod to move to the left, and the injection molding machine performs the mold locking action.

[0022] Specifically, the pressurization device includes a first cartridge valve, a hydraulically controlled check valve, and an auxiliary oil tank. The first cartridge valve is provided with oil port X, oil port A3, and oil port B3. Oil port X is connected to the hydraulically controlled check valve through a first return oil branch pipe. In this embodiment, the hydraulically controlled check valve is a two-position two-way hydraulically controlled check valve. The hydraulically controlled check valve is connected to the auxiliary oil tank. Oil port B3 is connected to the oil pipe between oil port A and the rodless cavity A1 of the mold opening and closing cylinder through a first branch pipe 109. A first branch pipe is connected between the first branch pipe 109 and the first return oil branch pipe. Oil port A3 is connected to the oil pipe between oil port T and the flow obstruction device through a second branch pipe.

[0023] The principle of the booster device: The hydraulic control check valve is normally closed. An electromagnetic pilot valve 4YA is provided on the left side of the hydraulic control check valve. When the hydraulic control check valve is not energized, hydraulic oil can flow from port A3 to port B3 of the first cartridge valve 10, but cannot flow from port B3 to port A3. When the hydraulic control check valve 9 is energized (i.e., 4YA is energized), the hydraulic oil at port X of the pilot control port of the first cartridge valve 10 flows to the auxiliary oil tank through the hydraulic control check valve. When the force generated by the hydraulic oil at port B3 is greater than the spring force inside the first cartridge valve 10, the valve core is opened, and the hydraulic oil flows from port B3 to port A3.

[0024] More specifically, the flow-blocking device includes a second cartridge valve and a second solenoid directional valve. The second cartridge valve has ports x, A2, and B2. The second solenoid directional valve has ports P1, B1, T1, and A1. In this embodiment, the second solenoid directional valve is a two-position four-way solenoid directional valve. Port B1 is connected to the oil pipe between ports T and A2 through a first flow-blocking branch pipe. Ports x, P1, and the first flow-blocking branch pipe are interconnected through a first tee pipe. Port B2 is connected to the main oil tank through an oil outlet pipe. The oil outlet pipe is connected to port T1 through an oil outlet branch pipe. A return oil pipe is provided between port A1 and the oil outlet branch pipe.

[0025] The principle of the flow obstruction device: The dotted line in the figure is the pilot control circuit of the second cartridge valve 6 in the flow obstruction device. The second electromagnetic directional valve 7 is the pilot control valve. In this embodiment, the second electromagnetic directional valve 7 is provided with an electromagnetic pilot valve 3YA on the left side. In the design of the oil circuit block, the oil port P1 of the second electromagnetic directional valve 7 should be connected to the oil port B1, and the oil port T1 should be connected to the oil port A1. When the second solenoid directional valve 7 is not energized, as shown in the figure, port P1 is connected to port A1, and port T1 is connected to port B1. At this time, the pilot control circuit of the second cartridge valve 6 is connected to the main oil tank. The hydraulic oil at port A2 of the second cartridge valve 6 overcomes the spring pressure inside the second cartridge valve 6, pushing up the valve core, so that port A2 connects to port B2 and flows back to the main oil tank through the outlet pipe. When the second solenoid directional valve 7 is energized (i.e., the solenoid pilot valve 3YA is energized), port P1 is connected to port B1, and port T1 is connected to port A1. At this time, a small amount of hydraulic oil... A portion of the hydraulic oil flows from port A2 to port B2 of the second cartridge valve 6, while most flows into the first flow-blocking branch pipe, which then flows to the first tee pipe and port B1 respectively. Part of the hydraulic oil from the first tee pipe flows to port x, and part flows from port P1 to port B1. The hydraulic oil flowing to port x seals the internal valve core of the second cartridge valve 6, keeping the pilot control circuit closed. A2 and B2 are disconnected, preventing the hydraulic oil at port A2 from flowing back to the main oil tank. The hydraulic oil flowing from the first flow-blocking branch pipe into port B1 and the hydraulic oil flowing from port P1 into port B1 form a flow-blocking passage, enhancing the sealing effect of the valve core.

[0026] The specific actions are as follows:

[0027] The working condition of the hydraulic cylinder is as follows Figure 1As shown, when oil enters the rodless chamber A1, the piston rod moves to the right, which is the mold opening action. When the motor 3 starts, hydraulic oil is drawn from the main oil tank through the filter 1 and then to the electro-hydraulic directional valve 8. At this time, the solenoid pilot valve 2YA is energized, and the valve core moves to the left, so that the hydraulic oil flows from the oil port P to the oil port A of the electro-hydraulic directional valve 8. The oil port A of the electro-hydraulic directional valve 8 is connected to the rodless chamber A1 of the hydraulic cylinder, which makes the piston rod move to the right, and the injection molding machine performs the mold opening action. Meanwhile, the hydraulic oil in the rod chamber B1 of the hydraulic cylinder flows from port B to port T through the electro-hydraulic directional valve 8. At this time, in the flow-blocking device, the solenoid pilot valve 3YA of the second solenoid directional valve 7 is energized. Port P1 of the second solenoid directional valve 7 is connected to port B1, and port T1 is connected to port A1. At this time, a small portion of the hydraulic oil flows from port A2 of the second cartridge valve 6 to port B2, while most of it flows into the first flow-blocking branch pipe, flowing to the first three-way pipe and port B1 respectively. A portion of the first three-way pipe flows to x. A portion of the hydraulic oil flows from port P1 to port B1. The hydraulic oil flowing to port x seals the internal valve core of the second cartridge valve 6, and the pilot control circuit is in a closed state. A2 and B2 are disconnected, so that the hydraulic oil at port A2 cannot flow back to the main oil tank through port B2. The hydraulic oil flowing into port B1 from the first flow-blocking branch pipe and the hydraulic oil flowing into port B1 from port P1 form a flow-blocking oil channel, which strengthens the sealing effect of the valve core. At this time, the hydraulic oil flowing to the rod chamber B1 of port A2 can be blocked, preventing it from flowing back to the main oil tank. Instead, it enters the first cartridge valve 10 in the booster device through the second branch pipe and flows to the rodless chamber A1 through the first branch pipe 109, forming a differential circuit, increasing the oil flow rate of the rodless chamber A1, thereby speeding up the mold opening speed.

[0028] To lock the mold, when motor 3 starts, hydraulic oil is drawn from the main oil tank through filter 1 and then to electro-hydraulic directional valve 8. At this time, solenoid valve 1YA is energized, and the valve core of electro-hydraulic directional valve 8 moves to the right. Hydraulic oil flows from port P to port B and from port A to port T of electro-hydraulic directional valve 8. Port A of electro-hydraulic directional valve 8 is connected to the rodless chamber A1 of the hydraulic cylinder, and port B of electro-hydraulic directional valve 8 is connected to the rod chamber B1 of the hydraulic cylinder, causing the piston rod to move to the left, and the injection molding machine performs the mold locking action. At this time, the solenoid pilot valve 4YA of the hydraulic control check valve 9 is energized, allowing the hydraulic oil at the pilot control port X of the first cartridge valve 10 to flow through the first return branch pipe to the auxiliary oil tank via the hydraulic control check valve 9, thus connecting port X with the hydraulic control check valve 9 and relieving the problem of the valve core inside the first cartridge valve 10 being sealed. At this time, part of the hydraulic oil in the rodless chamber A1 of the hydraulic cylinder flows into port B3 through the first branch pipe 109, and part flows through port A of the electro-hydraulic directional valve 8 to port T. When the force generated by the hydraulic oil at port B3 is greater than the spring force inside the first cartridge valve 10, the valve core is pushed open, and the hydraulic oil flows from port B3 to port A3, and then through the second branch pipe to port A2. At this time, the solenoid pilot valve 3YA of the second solenoid directional valve 7 is not energized. Port P1 connects to port A1, and port B1 connects to port T1. Part of the hydraulic oil flows into the first flow-blocking branch pipe, and part opens the valve core of the second cartridge valve 6, flowing back to the main oil tank from the outlet pipe. Part of the hydraulic oil flowing into the first flow-blocking branch pipe flows into port P1 through the first three-way pipe and then into the main oil tank through the return pipe and the outlet branch pipe; another part flows into port B1 and into the main oil tank through the outlet branch pipe.

[0029] More specifically, an overflow valve and a pressure sensor are also provided between the oil pump and the steering device. The overflow valve is used to prevent the oil pump from drawing too much oil or the oil passage from becoming blocked, thereby damaging the motor. The pressure sensor is used to sense the pressure in the oil pipe to prevent the pressure from being too high or too low, which would affect the operation.

[0030] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydraulic system applied to the quick opening and closing mold of an injection molding machine, comprising an opening and closing mold oil cylinder, an oil pump (2) and a main oil tank (90), the oil pump (2) is connected with a motor (3), the opening and closing mold oil cylinder, the oil pump (2) and the main oil tank (90) are communicated in sequence through an oil pipe, characterized in that: The opening and closing mold oil cylinder is provided with a pressure increasing device, a steering device and a flow resistance device between the oil pump (2), the opening and closing mold oil cylinder and the oil pump (2) are communicated with the steering device through oil pipes, the flow resistance device is communicated with the steering device through one end of the oil pipe and communicated with the main oil tank (90) through the other end, the pressure increasing device is communicated with the oil pipe between the opening and closing mold oil cylinder and the steering device through one end of the oil pipe and communicated with the oil pipe between the flow resistance device and the steering device through the other end, the oil pipe is provided with a hydraulic medium, the hydraulic medium is opened and closed through the cooperation of the pressure increasing device, the steering device and the flow resistance device, the quick start and reset of the opening and closing mold oil cylinder are realized, the steering device comprises an electro-hydraulic reversing valve (8), the electro-hydraulic reversing valve (8) is provided with oil port P, oil port B, oil port T and oil port A, the oil port P is communicated with the oil pump (2) through the oil pipe, the oil port B is communicated with the rod cavity B1 of the opening and closing mold oil cylinder through the oil pipe, the oil port T is communicated with the flow resistance device through the oil pipe, the oil port A is communicated with the rodless cavity A1 of the opening and closing mold oil cylinder through the oil pipe, the electro-hydraulic reversing valve (8) can make the oil port A and the oil port P communicate, the oil port T and the oil port B communicate or make the oil port A and the oil port T communicate, the oil port P and the oil port B communicate, the pressure increasing device comprises a first cartridge valve (10), a hydraulic control check valve (9) and a sub-oil tank (99), the first cartridge valve (10) is provided with oil port X, oil port A3 and oil port B3, the oil port X is communicated with the hydraulic control check valve (9) through the first oil return branch pipe (101), the hydraulic control check valve (9) is communicated with the sub-oil tank (99), the oil port B3 is communicated with the oil pipe between the oil port A and the rodless cavity A1 of the opening and closing mold oil cylinder through the first branch pipe (109), the first branch pipe (109) and the first oil return branch pipe (101) are communicated with the first branch pipe (102), the oil port A3 is communicated with the oil pipe between the oil port T and the flow resistance device through the second branch pipe (103), the flow resistance device comprises a second cartridge valve (6) and a second electromagnetic reversing valve (7), the second cartridge valve (6) is provided with oil port x, oil port A2 and oil port B2, the second electromagnetic reversing valve (7) is provided with oil port P3, oil port B3, oil port T3 and oil port A3, the oil port B3 is communicated with the oil pipe between the oil port T and the oil port A2 through the first flow resistance branch pipe (104), the oil port x, the oil port P3 and the first flow resistance branch pipe (104) are communicated with each other through the first three-way pipe (105), the oil port B2 is communicated with the main oil tank (90) through the oil outlet pipe (106), the oil outlet pipe (106) is communicated with the oil outlet branch pipe (107) through the oil outlet branch pipe (107), the oil port A3 is provided with the oil return pipe (108) between the oil outlet branch pipe (107). ​ 2. The hydraulic system for quick opening and closing mold of injection molding machine according to claim 1, characterized in that: The electro-hydraulic reversing valve (8) is a three-position four-way electro-hydraulic reversing valve (8).

3. The hydraulic system for quick opening and closing mold of injection molding machine according to claim 1, wherein: The second electromagnetic reversing valve (7) is a two-position four-way electromagnetic reversing valve.

4. The hydraulic system for quick opening and closing mold of injection molding machine according to claim 1, wherein: The hydraulic control check valve (9) is a two-position two-way hydraulic control check valve (9).

5. The hydraulic system for quick opening and closing mold of injection molding machine according to claim 1, wherein: The oil pump (2) is further provided with an overflow valve (4) and a pressure sensor (5) between the steering device.

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