An injection molding machine mold opening and closing hydraulic circuit control system

Abstract

This utility model discloses a hydraulic control system for the mold opening and closing of an injection molding machine, including a hydraulic cylinder and a working hydraulic circuit connected to the hydraulic cylinder. The hydraulic cylinder includes a mold closing chamber and a mold opening chamber. The working hydraulic circuit is equipped with a three-position four-way hydraulic control valve, a two-position four-way cam valve, a first three-position four-way solenoid valve, a second two-position four-way solenoid valve, and a second three-position four-way solenoid valve, all communicating with the mold closing and mold opening chambers. The B port of the three-position four-way hydraulic control valve and the P port of the second three-position four-way solenoid valve are connected to the mold closing chamber of the hydraulic cylinder. The A port of the three-position four-way hydraulic control valve is connected to the mold opening chamber of the hydraulic cylinder. The P port of the three-position four-way hydraulic control valve and the P port of the first three-position four-way solenoid valve are connected to the hydraulic circuit system P. This utility model can achieve smooth and stable mold opening and closing. By controlling the corresponding valves, vibration and impact can be effectively reduced. The working hydraulic circuit is simple and easy to inspect and maintain.

Description

Technical Field

[0001] This utility model relates to the field of injection molding machine technology, specifically to an injection molding machine mold opening and closing oil circuit control system. Background Technology

[0002] Injection molding machines require hydraulic circuits to open and close the mold. However, the hydraulic circuits for mold opening and closing in typical injection molding machines often have problems due to improper design, including:

[0003] The first stage of mold opening: When the mold opening starts, the oil cylinder is controlled by a small-diameter solenoid reversing valve to resist the vibration when the mechanical hinge releases the clamping force at the moment of mold opening, so as to realize the back pressure of mold opening; however, the small valve has a small oil flow rate, the mold opening speed is slow, the instantaneous inertial force is small, and the mold often fails to open.

[0004] The second stage of mold opening: By increasing the oil inlet and outlet by adding a large-diameter hydraulic mold opening valve, and using both large-diameter and small-diameter valves together to increase the oil flow of the system, rapid mold opening can be achieved; however, the large-diameter valve has a slow response, and there is already a certain pressure in the oil circuit during the switching process. The impact and vibration caused by the valve switching into the oil circuit system will make the mold opening action unsmooth.

[0005] The third stage of mold opening: close the large-diameter mold opening valve and use the small-diameter valve alone to slow down the mold opening and finally control it at the set position; however, when the large-diameter valve is closed, the system oil return often has a certain speed. Suddenly closing the large-diameter valve will generate vibration and impact again, causing obvious pauses in mold opening. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide an injection molding machine mold opening and closing oil circuit control system, which can solve the problems described in the background art.

[0007] The technical solution to achieve the purpose of this utility model is as follows: a hydraulic control system for opening and closing molds of an injection molding machine, including a hydraulic cylinder and a working hydraulic circuit connected to the hydraulic cylinder. The hydraulic cylinder includes a mold closing hydraulic chamber and a mold opening hydraulic chamber. The working hydraulic circuit is equipped with a three-position four-way hydraulic control valve, a two-position four-way cam valve, a first three-position four-way solenoid valve, a second four-way solenoid valve, and a second three-position four-way solenoid valve, which are connected to the mold closing hydraulic chamber and the mold opening hydraulic chamber.

[0008] The B port of the three-position four-way hydraulic directional valve and the P port of the second three-position four-way solenoid directional valve are connected to the mold closing oil chamber of the hydraulic cylinder. The A port of the three-position four-way hydraulic directional valve is connected to the mold opening oil chamber of the hydraulic cylinder. The P port of the three-position four-way hydraulic directional valve is connected to the P port of the first three-position four-way solenoid directional valve and then connected to the oil circuit system P. The B port of the first three-position four-way solenoid directional valve is connected to the P port of the two-position four-way cam valve. The A ports of the two-position four-way cam valve and the A ports of the first three-position four-way solenoid directional valve are respectively connected to the pilot control oil ports on both sides of the three-position four-way hydraulic directional valve.

[0009] The T port and B port of the second three-position four-way solenoid directional valve are connected and jointly connected to the oil circuit system T. The A port of the second three-position four-way solenoid directional valve, the T port of the three-position four-way hydraulic directional valve, and the P port of the two-position four-way solenoid directional valve are all connected. The A port and B port of the two-position four-way solenoid directional valve are also connected to the T port and B port of the second three-position four-way solenoid directional valve, the T port of the first three-position four-way solenoid directional valve, and then jointly connected to the oil circuit system T.

[0010] Furthermore, a damping element is installed on port A of the two-position four-way solenoid directional valve to increase damping.

[0011] Furthermore, the T-port of the two-position four-way cam valve is connected to the oil tank of the oil circuit system.

[0012] Furthermore, the first three-position four-way solenoid directional valve serves as the control pilot valve for the three-position four-way hydraulic directional valve.

[0013] Furthermore, the model of the three-position four-way hydraulic control directional valve is the O-type three-position four-way hydraulic control directional valve.

[0014] Furthermore, the model of the two-position four-way cam valve is a two-position four-way mechanical directional valve with stroke control.

[0015] Furthermore, the second three-position four-way solenoid directional valve is a three-position four-way solenoid directional valve with the A port in the middle position connected to the T port.

[0016] Furthermore, the model of the two-position four-way solenoid directional valve is a two-position four-way solenoid directional valve with P port connected to A port and T port connected to B port when de-energized.

[0017] The beneficial effects of this invention are as follows: This invention enables smooth and stable mold opening and closing; by configuring and controlling the corresponding valves, vibration and impact can be effectively reduced. The entire working oil circuit is simple and easy to inspect and maintain. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model;

[0019] In the diagram, 1-oil cylinder, 2-three-position four-way hydraulic directional valve, 3-two-position four-way cam valve, 4-first three-position four-way solenoid directional valve, 5-two-position four-way solenoid directional valve, and 6-second three-position four-way solenoid directional valve. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0021] like Figure 1 As shown, an injection molding machine mold opening and closing oil circuit control system includes a hydraulic cylinder 1 and a working oil circuit connected to the hydraulic cylinder 1. The hydraulic cylinder 1 includes a mold closing oil chamber and a mold opening oil chamber. The working oil circuit is equipped with a three-position four-way hydraulic control valve 2, a two-position four-way cam valve 3, a first three-position four-way solenoid valve 4, a two-position four-way solenoid valve 5, and a second three-position four-way solenoid valve 6, which are connected to the mold closing oil chamber and the mold opening oil chamber.

[0022] The B port of the three-position four-way hydraulic directional valve 2 and the P port of the second three-position four-way solenoid directional valve 6 are connected together to the mold closing oil chamber of the cylinder 1. The A port of the three-position four-way hydraulic directional valve 2 is connected to the mold opening oil chamber of the cylinder 1. The P port of the three-position four-way hydraulic directional valve 2 and the P port of the first three-position four-way solenoid directional valve 4 are connected together to the oil circuit system P. The B port of the first three-position four-way solenoid directional valve 4 is connected to the P port of the two-position four-way cam valve 3. The A ports of the two-position four-way cam valve 3 and the A ports of the first three-position four-way solenoid directional valve 4 are respectively connected to the pilot control oil ports on both sides of the three-position four-way hydraulic directional valve 2.

[0023] The T port of the two-position four-way cam valve 3 is connected to the system oil tank.

[0024] Among them, the first three-position four-way solenoid directional valve 4 serves as the pilot valve for the control of the three-position four-way hydraulic directional valve 2.

[0025] The T port and B port of the second three-position four-way solenoid directional valve 6 are connected together to the oil circuit system T. The A port of the second three-position four-way solenoid directional valve 6, the T port of the three-position four-way hydraulic directional valve 2, and the P port of the two-position four-way solenoid directional valve 5 are also connected together. The A and B ports of the two-position four-way solenoid directional valve 5 are also connected to the T and B ports of the second three-position four-way solenoid directional valve 6 and the T port of the first three-position four-way solenoid directional valve 4, and then together they are connected to the oil circuit system T.

[0026] In an optional implementation, a damping element is provided at port A of the two-position four-way solenoid directional valve 5 to increase damping. For example, a damping element with a diameter of 1.5mm is provided. Of course, the diameter of the damping element can be adjusted according to the actual situation.

[0027] Among them, the three-position four-way hydraulic control directional valve 2 is an O-type three-position four-way hydraulic control directional valve, and its model can be DSG-03-3C2; the two-position four-way cam valve 3 is a two-position four-way mechanical directional valve with stroke control, and its model can be DCG-02-2B3; the second three-position four-way solenoid directional valve 6 is a three-position four-way solenoid directional valve with the A port connected to the T port in the middle position, and its model can be DSG-03-3C12; and the two-position four-way solenoid directional valve 5 is a two-position four-way solenoid directional valve with the P port connected to the A port and the T port connected to the B port when de-energized, and its model can be DSG-01-2B3.

[0028] During the mold closing process:

[0029] After initiating the mold closing action, the process sequentially enters the slow mold closing start stage, the fast mold closing stage, the low-pressure mold protection stage, and the high-pressure mold closing stage.

[0030] Slow start-up phase of mold closing: The right valve YV1 of the first three-position four-way solenoid valve 4, acting as the pilot valve, is energized. The valve core inside the first three-position four-way solenoid valve 4 moves to the left, allowing pressurized oil to connect to port B through port P on the first three-position four-way solenoid valve 4, and then to port A through port P of the two-position four-way cam valve 3. The pressurized oil flowing out of port A of the two-position four-way cam valve 3 pushes the valve core of the main valve body to the left through the pilot port of the three-position four-way hydraulic directional valve 2. The pressurized oil then connects to port B through port P of the three-position four-way hydraulic directional valve 2, thus entering the mold closing oil chamber. Then, the pressurized oil in the mold opening oil chamber enters port T through port A of the three-position four-way hydraulic directional valve 2. Part of the pressurized oil enters port T through port A of the second three-position four-way solenoid valve 6 and returns to the oil circuit system T; the other part enters port A through port P of the two-position four-way solenoid valve 5 and then returns to the oil circuit system T.

[0031] Rapid mold closing stage: When entering the rapid mold closing stage, the left valve YV2 of the second three-position four-way solenoid valve 6 is energized, and the valve core moves to the right, so that the pressure oil in the mold opening oil chamber is conducted through port A on the second three-position four-way solenoid valve 6 to port P and enters the mold closing oil chamber, realizing differential mold closing control, which increases the oil inlet of the mold closing oil chamber and thus realizes rapid mold closing.

[0032] Low-pressure mold protection stage during mold closing: When the mold closing process transitions from the rapid mold closing stage to the low-pressure mold protection stage, the left valve (YV2) of the second and third position four-way solenoid directional valve 6 is de-energized, while the right valve (YV24) is energized. The valve core moves to the left, allowing the oil entering the mold closing cavity to enter the T port through the P port of valve 6 and return to the oil circuit system T. This reduces the oil entering the mold closing oil cavity, relieves the pressure in the mold closing oil cavity, and reduces the mold closing speed, thus achieving the mold protection function.

[0033] High pressure mold closing stage: From the low pressure mold closing stage to the high pressure mold closing stage, the right valve (YV24) of the second and third position four-way solenoid valve 6 is de-energized, and the working oil circuit returns to the slow mold closing state, realizing high pressure mold locking.

[0034] During the entire mold closing process, if the front safety door of the injection molding machine is opened at any time, the two-position four-way cam valve 3 will cut off the pilot pressure oil of the three-position four-way hydraulic directional valve 2. The valve core of the three-position four-way hydraulic directional valve 2 will automatically return to the neutral position under the action of the valve body spring, locking the oil inlet and outlet of the oil cylinder 1, preventing the mold closing action, and achieving safety protection of the hydraulic system. The three-position four-way hydraulic directional valve 2 is a large-diameter hydraulic directional valve; from the start of mold closing to the end of mold closing, there is no switching of the valve core position, resulting in minimal hydraulic shock during the entire mold closing action.

[0035] During the mold-making process:

[0036] After initiating the mold opening action, the process sequentially enters the slow mold opening start stage, the fast mold opening stage, and the slow mold opening positioning stage.

[0037] Slow start-up phase of mold opening: After the mold opening action is initiated, the left valve YV3 of the first three-position four-way solenoid directional valve 4, which acts as the pilot valve for the three-position four-way hydraulic directional valve 2, is energized. Its valve core moves to the right, and the pressurized oil is connected to port A through port P of the first three-position four-way solenoid directional valve 4. Then, through the pilot port of the three-position four-way hydraulic directional valve 2, it pushes the valve core of the main valve body to move to the right, and the pressurized oil enters port A through port P of the three-position four-way hydraulic directional valve 2, thus entering the mold opening oil chamber. At the same time, the left valve YV2 of the second three-position four-way solenoid directional valve 6 is energized, and its valve core moves to the right, so that the pressurized oil in the mold closing oil chamber can only enter port A through port P of the second-position four-way solenoid directional valve 5, and then enter the oil circuit system T. Damping is added to port A, which reduces the oil flow rate and makes the return oil flow rate much smaller than the inlet oil flow rate, thus forming a larger mold opening back pressure during mold opening start-up, effectively resisting the impact and vibration when the mechanical hinge releases the clamping force.

[0038] Rapid mold opening stage: Upon entering the rapid mold opening stage, the left valve YV2 of the second / third position four-way solenoid valve 6 is de-energized, while the right valve YV24 is energized, causing its valve core to move to the left. Simultaneously, the second / third position four-way solenoid valve 5 is energized, causing its valve core to move to the right. The return oil from the mold closing cylinder 1 enters the B port of the second / third position four-way solenoid valve 6 and returns to the oil circuit system T. At the same time, another return oil from the mold closing cylinder 1 enters the T port through the B port of the third position four-way hydraulic control valve 2. Part of the return oil enters the T port from the A port of the second / third position four-way solenoid valve 6 and returns to the oil circuit system T, while part of the return oil enters the T port through the P port of the second / third position four-way solenoid valve 5. During the rapid mold opening stage, the return oil flow rate is much greater than the inflow oil flow rate, resulting in low return oil resistance, achieving rapid mold opening, and simultaneously saving energy.

[0039] Slow mold opening and positioning stage: When transitioning from fast mold opening to slow mold opening, the right valve YV24 of the second and third position four-way solenoid valve 6 is de-energized, while the left valve YV2 is energized, causing the valve core to move to the right and blocking the return oil from the mold closing oil chamber to the second and third position four-way solenoid valve 6, thus forming mold opening back pressure. At the same time, the second position four-way solenoid valve 5 is de-energized, and the return oil from the mold closing oil chamber can only enter the A port through the damped P port of the second position four-way solenoid valve 5 and return to the oil circuit system T, forming a larger mold opening back pressure. This allows the mold opening action to decelerate very quickly and stop precisely at the control position.

[0040] This invention enables smooth and stable mold opening and closing, and by configuring appropriate control valves, vibration and impact can be effectively reduced. The entire working oil circuit is simple and easy to inspect and maintain.

[0041] The embodiments disclosed in this specification are merely illustrative of one aspect of the features of this utility model. The protection scope of this utility model is not limited to this embodiment, and any other functionally equivalent embodiments fall within the protection scope of this utility model. Those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this utility model.

Claims

1. An injection molding machine mold opening and closing hydraulic circuit control system characterized by, It includes a hydraulic cylinder and a working oil circuit connected to the hydraulic cylinder. The hydraulic cylinder includes a mold closing oil chamber and a mold opening oil chamber. The working oil circuit is equipped with a three-position four-way hydraulic control directional valve, a two-position four-way cam valve, a first three-position four-way solenoid directional valve, a second four-way solenoid directional valve, and a second three-position four-way solenoid directional valve, which are connected to the mold closing oil chamber and the mold opening oil chamber. The B port of the three-position four-way hydraulic directional valve and the P port of the second three-position four-way solenoid directional valve are connected to the mold closing oil chamber of the hydraulic cylinder. The A port of the three-position four-way hydraulic directional valve is connected to the mold opening oil chamber of the hydraulic cylinder. The P port of the three-position four-way hydraulic directional valve is connected to the P port of the first three-position four-way solenoid directional valve and then connected to the oil circuit system P. The B port of the first three-position four-way solenoid directional valve is connected to the P port of the two-position four-way cam valve. The A ports of the two-position four-way cam valve and the A ports of the first three-position four-way solenoid directional valve are respectively connected to the pilot control oil ports on both sides of the three-position four-way hydraulic directional valve. The T port and B port of the second three-position four-way solenoid directional valve are connected and together connected to the oil circuit system T. The A port of the second three-position four-way solenoid directional valve, the T port of the three-position four-way hydraulic directional valve, and the P port of the two-position four-way solenoid directional valve are all connected. The A port and B port of the two-position four-way solenoid directional valve are also connected to the T port and B port of the second three-position four-way solenoid directional valve, and the T port of the first three-position four-way solenoid directional valve, and together they are connected to the oil circuit system T.

2. The injection molding machine clamp to drag hydraulic circuit control system of claim 1 wherein, A damping element is installed on port A of the two-position four-way solenoid directional valve to increase damping.

3. The injection molding machine clamp to drag hydraulic circuit control system of claim 1 wherein, The T port of the two-position four-way cam valve is connected to the oil tank of the oil circuit system.

4. The injection molding machine clamp to drag hydraulic circuit control system of claim 1 wherein, The first three-position four-way solenoid directional valve serves as the pilot valve for the control of the three-position four-way hydraulic directional valve.

5. The injection molding machine clamp to drag hydraulic circuit control system of claim 1 wherein, The model number of the three-position four-way hydraulic control directional valve is O-type three-position four-way hydraulic control directional valve.

6. The injection molding machine clamp to drag hydraulic circuit control system of claim 1 wherein, The model of the two-position four-way cam valve is a two-position four-way mechanical directional valve with stroke control.

7. The injection molding machine clamp to drag hydraulic circuit control system of claim 1 wherein, The second three-position four-way solenoid directional valve is a three-position four-way solenoid directional valve with the A port in the middle position open to the T port.

8. The injection molding machine clamp to drag hydraulic circuit control system of claim 1 wherein, The two-position four-way solenoid directional valve is a two-position four-way solenoid directional valve with P port connected to A port and T port connected to B port when de-energized.

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