A nozzle control oil circuit and injection molding machine

Abstract

The utility model relates to the technical field of control oil circuit, and specifically discloses a nozzle control oil circuit and injection molding machine, nozzle control oil circuit includes oil cylinder, system oil port, reversing valve and bidirectional hydraulic control check valve, system oil port is used to through the reversing valve and supplies oil for the rod cavity or the rod cavity of oil cylinder, bidirectional hydraulic control check valve is located between oil cylinder and reversing valve, first working oil port, second working oil port, first control oil port and second control oil port are equipped on this bidirectional hydraulic control check valve, wherein, first working oil port is connected with the rod cavity of oil cylinder, second working oil port is connected with the rod cavity of oil cylinder, when the pressure of pressure oil provided by system oil port is greater than preset pressure, can control bidirectional hydraulic control check valve to open, to realize the flow of oil inlet and oil return, when system pressure is lower than preset pressure, bidirectional hydraulic control check valve is closed, and it can block the rod cavity and the rod cavity of oil cylinder, makes nozzle maintain closed state, effectively prevents the leakage of dissolving material.

Description

Technical Field

[0001] This utility model relates to the technical field of nozzle control oil circuits, and specifically to a nozzle control oil circuit and an injection molding machine. Background Technology

[0002] The hydraulic nozzle of the injection molding machine is a key component in the injection molding process. It is used to control the flow of molten plastic and the injection process. The hydraulic nozzle is controlled by the hydraulic system to open and close. During the injection holding pressure stage, the nozzle is open to allow the molten plastic to flow smoothly into the mold cavity. When the injection holding pressure stage is over, the nozzle is closed to prevent plastic backflow and ensure that the plastic in the injection barrel does not leak out.

[0003] However, when the main oil circuit pressure of a traditional injection molding machine hydraulic nozzle is unstable, the lack of a one-way valve circuit or the conventional P-port one-way valve circuit can lead to a decrease in nozzle oil pressure due to leakage of oil from the reversing valve. This is especially prone to problems such as nozzle not closing tightly or material leakage during pre-plasticizing. These problems not only lead to material waste and contamination of molds and equipment, but also reduce production efficiency and product molding quality. Utility Model Content

[0004] This utility model addresses the aforementioned problems. Its purpose is to provide a nozzle control oil circuit and injection molding machine that can solve the problem that the nozzle cannot reliably maintain a closed state when the system pressure is insufficient.

[0005] To achieve the above objectives, this utility model provides a nozzle control oil circuit, including an oil cylinder, a system oil port, a reversing valve, and a bidirectional hydraulic control check valve. The bidirectional hydraulic control check valve is located between the oil cylinder and the reversing valve, and the bidirectional hydraulic control check valve is provided with a first working oil port, a second working oil port, a first control oil port, and a second control oil port. The first working oil port is connected to the rodless chamber of the oil cylinder, and the second working oil port is connected to the rod chamber of the oil cylinder.

[0006] The reversing valve is provided with a first oil inlet, a first variable oil inlet and a second variable oil inlet. The first oil inlet is connected to the system oil inlet, the first variable oil inlet is connected to the first control oil inlet, and the second variable oil inlet is connected to the second control oil inlet.

[0007] When the reversing valve is energized, the system oil port is connected to the second control oil port through the reversing valve to open the return oil circuit from the rodless chamber of the cylinder to the oil tank, and allow the pressure oil output from the system oil port to enter the rodless chamber of the cylinder through the second working oil port;

[0008] When the reversing valve is de-energized, the system oil port is connected to the first control oil port through the reversing valve to open the return oil circuit from the rod chamber of the cylinder to the oil tank, and allow the pressure oil output from the system oil port to enter the rod chamber of the cylinder through the first working oil port.

[0009] When the nozzle is in the closed state, and the pressure at the system port is less than the preset pressure, the bidirectional hydraulic check valve closes to block the rod-side and rodless-side chambers of the cylinder, thereby keeping the nozzle in the closed state.

[0010] According to the above-described nozzle control oil circuit, the bidirectional hydraulic control check valve includes a first check valve and a second check valve. The first check valve is located between the first variable oil port and the rodless chamber of the oil cylinder, and the opening of the first check valve faces the rodless chamber of the oil cylinder. The second check valve is located between the second variable oil port and the rod chamber of the oil cylinder, and the opening of the second check valve faces the rod chamber of the oil cylinder.

[0011] According to the above-described nozzle control oil circuit, the first control oil port is located between the first check valve and the first variable oil port, and can control the second check valve to open; the second control oil port is located between the second check valve and the second variable oil port, and can control the first check valve to open.

[0012] According to the above-described nozzle control oil circuit, the bidirectional hydraulic control check valve further includes a control piston, which is located between the valve core of the first check valve and the valve core of the second check valve, and is displaceable to drive the valve core of the first check valve or the second check valve to open.

[0013] According to the above-described nozzle control oil circuit, the bidirectional hydraulic check valve is further provided with a first pilot chamber and a second pilot chamber. The first control port is connected to the first pilot chamber and can drive the control piston to move along a first direction to open the valve core of the second check valve. The second control port is connected to the second pilot chamber and can drive the control piston to move along a second direction to open the valve core of the first check valve.

[0014] According to the above-described nozzle control oil circuit, the reversing valve is further provided with a first return oil port, which is connected to the oil tank.

[0015] According to the above-described nozzle control oil circuit, the reversing valve is also equipped with an electromagnet. When the electromagnet is energized, the first oil inlet is connected to the second variable oil port and the first variable oil port is connected to the first return oil port. When the electromagnet is de-energized, the first oil inlet is connected to the first variable oil port and the second variable oil port is connected to the first return oil port.

[0016] The nozzle control oil circuit described above further includes a pressure reducing valve, which is arranged between the system oil port and the reversing valve. The oil inlet of the pressure reducing valve is connected to the system oil port, and the oil outlet of the pressure reducing valve is connected to the first oil inlet.

[0017] The nozzle control oil circuit described above also includes a pressure gauge, which is arranged at the oil outlet of the pressure reducing valve.

[0018] An injection molding machine includes a nozzle control oil circuit as described above.

[0019] This utility model has the following beneficial effects:

[0020] 1. By installing a two-way hydraulic control check valve between the oil cylinder and the reversing valve, the two-way hydraulic control check valve closes when the system pressure is lower than the preset pressure. It can block the rod chamber and rodless chamber of the oil cylinder, keep the nozzle closed, and effectively prevent the leakage of molten material.

[0021] 2. The bidirectional hydraulic control check valve adopts hydraulic pilot operation, which has a fast response speed and can control the opening and closing of the first check valve or the second check valve in a timely manner without affecting the oil return action of the oil cylinder.

[0022] 3. By installing a pressure reducing valve and a pressure gauge between the system oil port and the reversing valve, the input oil pressure can be precisely controlled, making it suitable for different process requirements. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the control oil circuit in an embodiment.

[0024] In the picture:

[0025] 100, Hydraulic cylinder; 200, System oil port; 300, Directional control valve; 310, Electromagnet; 400, Two-way hydraulic check valve; 410, First working oil port; 420, Second working oil port; 430, First control oil port; 440, Second control oil port; 450, First check valve; 460, Second check valve; 500, Oil tank; 600, Pressure reducing valve; 700, Pressure gauge. Detailed Implementation

[0026] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0027] like Figure 1As shown, a nozzle control oil circuit includes a hydraulic cylinder 100, a system oil port 200, a reversing valve 300, and a two-way hydraulic check valve 400. The system oil port 200 is used to supply oil to the rod chamber or rodless chamber of the hydraulic cylinder 100 through the reversing valve 300. When the system oil port 200 supplies oil to the rod chamber of the hydraulic cylinder 100, the hydraulic cylinder 100 can control the nozzle to open. When the system oil port 200 supplies oil to the rodless chamber of the hydraulic cylinder 100, the hydraulic cylinder 100 can control the nozzle to close. The hydraulic cylinder 100 includes a rod chamber and a rodless chamber.

[0028] The bidirectional hydraulic check valve 400 is located between the cylinder 100 and the directional valve 300. It plays a crucial locking role. That is, after the nozzle is closed, the bidirectional hydraulic check valve 400 can block the rod chamber and rodless chamber of the cylinder 100 so that the nozzle can remain closed and prevent oil leakage.

[0029] Specifically, the bidirectional hydraulic check valve 400 is provided with a first working port 410, a second working port 420, a first control port 430, and a second control port 440. The first working port 410 is connected to the rodless chamber of the cylinder 100, the second working port 420 is connected to the rod chamber of the cylinder 100, the first control port 430 is connected to the first working port 410, and the second control port 440 is connected to the second working port 420. Then, at system port 200... When oil is supplied to the first control port 430 through the reversing valve 300, a portion of the pressurized oil is delivered from the first control port 430 to the first working port 410 and eventually enters the rodless chamber of the cylinder 100. At this time, the nozzle is closed. The other portion of the pressurized oil is used as pilot oil from the first control port 430 to open the second working port 420, thereby opening the return oil path from the rod chamber of the cylinder 100 to the oil tank 500. The oil then flows through the reversing valve 300 at the system port 200. When oil is supplied to the second control port 440, a portion of the pressurized oil is delivered from the second control port 440 to the second working port 420, and finally enters the rod chamber of the cylinder 100. At this time, the nozzle opens. The other portion of the pressurized oil is supplied from the second control port 440 as pilot oil to control the opening of the first working port 410, thereby opening the return oil path from the rodless chamber of the cylinder 100 to the oil tank 500, thus meeting the needs of oil inlet and return. When the nozzle is closed, and When the pressure at system port 200 is less than the preset pressure, the hydraulic oil output from system port 200, when used as pilot oil, cannot open the bidirectional hydraulic check valve 400. That is, the bidirectional hydraulic check valve 400 is closed to block the rod chamber and rodless chamber of cylinder 100, so that the nozzle remains closed. In other words, the oil in the rod chamber and rodless chamber of cylinder 100 cannot flow out, and the position of the nozzle cannot be adjusted. The position can be maintained to prevent the nozzle from opening due to oil leakage from the directional valve 300.

[0030] Furthermore, the bidirectional hydraulic check valve 400 includes a first check valve 450 and a second check valve 460. The first check valve 450 is located between the first variable port and the rodless chamber of the cylinder 100, and the opening of the first check valve 450 faces the rodless chamber of the cylinder 100. The second check valve 460 is located between the second variable port and the rod chamber of the cylinder 100, and the opening of the second check valve 460 faces the rod chamber of the cylinder 100. When the first check valve 450 and the second check valve 460 are closed, they can only pass in one direction, that is, the oil in the rodless chamber and the rod chamber of the cylinder 100 cannot flow out. When the first check valve 450 and the second check valve 460 are open, they can pass in both directions, and the oil in the rodless chamber and the rod chamber of the cylinder 100 can be discharged.

[0031] Furthermore, the first control port 430 is located between the first check valve 450 and the first variable port, and can control the opening of the second check valve 460. The second control port 440 is located between the second check valve 460 and the second variable port, and can control the opening of the first check valve 450. That is, when pressure oil is input to the first control port 430, part of it can flow directly to the first check valve 450, and through the first check valve 450 it can flow to the rodless chamber of the cylinder 100, while the other part is... The second check valve 460 is used as a pilot oil to control the opening of the hydraulic oil. The hydraulic oil in the rod chamber of the cylinder 100 can return through the second check valve 460. When pressure oil is input to the second control port 440, part of it can flow directly to the second check valve 460 and then to the rod chamber of the cylinder 100. The other part is used as a pilot oil to control the opening of the first check valve 450. The hydraulic oil in the rodless chamber of the cylinder 100 can return through the first check valve 450.

[0032] Furthermore, the bidirectional hydraulic check valve 400 also includes a control piston located between the valve core of the first check valve 450 and the valve core of the second check valve 460, and movable to drive the valve core of either the first check valve 450 or the second check valve 460 to open. The bidirectional hydraulic check valve 400 has a first pilot chamber and a second pilot chamber. A first control port 430 communicates with the first pilot chamber and can drive the control piston to move in a first direction to open the valve core of the second check valve 460. A second control port 440 communicates with the second pilot chamber and can drive the control piston to move in a first direction to open the valve core of the second check valve 460. The control piston moves along the second direction to open the valve core of the first one-way valve 450. The first direction is opposite to the second direction, one to the left and the other to the right. That is, when oil enters the first control port 430, part of the oil drives the control piston to move to the left through the first pilot chamber to open the valve core of the second one-way valve 460. When oil enters the first control port 430, part of the oil drives the control piston to move to the right through the second pilot chamber to open the valve core of the first one-way valve 450. This achieves the opening control of the first one-way valve 450 and the second one-way valve 460.

[0033] In the above scheme, the pressure at the system oil port 200 is less than the preset pressure. The preset pressure refers to the valve core opening force of the first check valve 450 and the second check valve 460, that is, the restoring force provided by the spring in the valve core of the two check valves. Only when the pressure oil provided by the system oil port 200 is greater than the preset pressure can the pressure oil drive the valve core of the first check valve 450 or the second check valve 460 to open. Otherwise, both will always remain closed, and the oil in the rodless chamber and the rod chamber of the oil cylinder 100 cannot be discharged, thus maintaining the state.

[0034] Specifically, the directional valve 300 is provided with a first oil inlet, a first variable oil port, a second variable oil port, and a first return oil port. The first oil inlet is connected to the system oil port 200, the first variable oil port is connected to the first control oil port 430, the second variable oil port is connected to the second control oil port 440, and the first return oil port is connected to the oil tank 500. When the system oil port 200 is working, it can supply oil to the first oil inlet of the directional valve 300. By controlling whether the directional valve 300 is energized, the flow can be directed to the first or second variable oil port, thereby controlling the movement of the cylinder 100 and the nozzle. When the directional valve 300 is energized, the system oil port 200 is connected to the system oil inlet. The directional valve 300 is connected to the second control port 440 to open the return oil circuit from the rodless chamber of the cylinder 100 to the oil tank 500, and allows the pressure oil output from the system port 200 to enter the rodless chamber of the cylinder 100 through the second working port 420. When the directional valve 300 is de-energized, the system port 200 is connected to the first control port 430 through the directional valve 300 to open the return oil circuit from the rod chamber of the cylinder 100 to the oil tank 500, and allows the pressure oil output from the system port 200 to enter the rod chamber of the cylinder 100 through the first working port 410. The internal flow channel is controlled by whether the directional valve 300 is energized or not.

[0035] Furthermore, in this embodiment, the reversing valve 300 is an electromagnetic reversing valve 300. Therefore, an electromagnet 310 is also provided on the reversing valve 300. When the electromagnet 310 is energized, the first oil inlet is connected to the second variable oil port and the first variable oil port is connected to the first return oil port. When the electromagnet 310 is de-energized, the first oil inlet is connected to the first variable oil port and the second variable oil port is connected to the first return oil port. By controlling the connection of the channels inside the reversing valve 300 through the energization and de-energization of the electromagnet 310, the purpose of reversing is achieved.

[0036] Furthermore, it also includes a pressure reducing valve 600, which is arranged between the system oil port 200 and the reversing valve 300. The oil inlet of the pressure reducing valve 600 is connected to the system oil port 200, and the oil outlet of the pressure reducing valve 600 is connected to the first oil inlet. The pressure reducing valve 600 can reduce the pressure of the pressure oil input to the system oil port 200, ensuring that the pressure of the pressure oil is maintained within a suitable range.

[0037] Furthermore, it also includes a pressure gauge 700, which is located at the oil outlet of the pressure reducing valve 600. The pressure gauge 700 can be used to detect the hydraulic oil pressure after it has been reduced by the pressure reducing valve 600, thereby determining whether the hydraulic oil pressure meets the requirements.

[0038] In this embodiment, protection is also sought for an injection molding machine that includes the nozzle control oil circuit described above, wherein the control oil circuit is used to control the nozzles on the injection molding machine to perform corresponding actions.

[0039] The technical solution of this utility model has been described in detail above with reference to the accompanying drawings. The described embodiments are used to help understand the concept of this utility model. The specific embodiments described herein are merely illustrative examples of the spirit of this utility model. Those skilled in the art to which this utility model pertains can make various modifications or additions to the described specific embodiments or use similar methods to replace them, but without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

[0040] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0041] Furthermore, in this utility model, the use of terms such as "first," "second," and "a" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0043] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the protection scope claimed by this utility model.

Claims

1. A nozzle control oil circuit, characterized in that, The system includes a hydraulic cylinder, a system oil port, a reversing valve, and a two-way hydraulic control check valve. The two-way hydraulic control check valve is located between the hydraulic cylinder and the reversing valve, and the two-way hydraulic control check valve is provided with a first working oil port, a second working oil port, a first control oil port, and a second control oil port. The first working oil port is connected to the rodless chamber of the hydraulic cylinder, and the second working oil port is connected to the rod chamber of the hydraulic cylinder. The reversing valve is provided with a first oil inlet, a first variable oil inlet and a second variable oil inlet. The first oil inlet is connected to the system oil inlet, the first variable oil inlet is connected to the first control oil inlet, and the second variable oil inlet is connected to the second control oil inlet. When the reversing valve is energized, the system oil port is connected to the second control oil port through the reversing valve to open the return oil circuit from the rodless chamber of the cylinder to the oil tank, and allow the pressure oil output from the system oil port to enter the rodless chamber of the cylinder through the second working oil port; When the reversing valve is de-energized, the system oil port is connected to the first control oil port through the reversing valve to open the return oil circuit from the rod chamber of the cylinder to the oil tank, and allow the pressure oil output from the system oil port to enter the rod chamber of the cylinder through the first working oil port. When the nozzle is in the closed state, and the pressure at the system port is less than the preset pressure, the bidirectional hydraulic check valve closes to block the rod-side and rodless-side chambers of the cylinder, thereby keeping the nozzle in the closed state.

2. The nozzle control oil circuit according to claim 1, characterized in that, The bidirectional hydraulic check valve includes a first check valve and a second check valve. The first check valve is located between the first variable port and the rodless chamber of the cylinder, and the opening of the first check valve faces the rodless chamber of the cylinder. The second check valve is located between the second variable port and the rod chamber of the cylinder, and the opening of the second check valve faces the rod chamber of the cylinder.

3. The nozzle control oil circuit according to claim 2, characterized in that, The first control port is located between the first check valve and the first variable port, and can control the second check valve to open. The second control port is located between the second check valve and the second variable port, and can control the first check valve to open.

4. The nozzle control oil circuit according to claim 3, characterized in that, The bidirectional hydraulic check valve further includes a control piston located between the valve core of the first check valve and the valve core of the second check valve, and is movable to drive the valve core of either the first check valve or the second check valve to open.

5. The nozzle control oil circuit according to claim 1, characterized in that, The bidirectional hydraulic check valve is further provided with a first pilot chamber and a second pilot chamber. The first control port is connected to the first pilot chamber and can drive the control piston to move in a first direction to open the valve core of the second check valve. The second control port is connected to the second pilot chamber and can drive the control piston to move in a second direction to open the valve core of the first check valve.

6. The nozzle control oil circuit according to claim 1, characterized in that, The reversing valve is also provided with a first oil return port, which is connected to the oil tank.

7. A nozzle control oil circuit according to claim 6, characterized in that, The reversing valve is also equipped with an electromagnet. When the electromagnet is energized, the first oil inlet is connected to the second variable oil port and the first variable oil port is connected to the first return oil port. When the electromagnet is de-energized, the first oil inlet is connected to the first variable oil port and the second variable oil port is connected to the first return oil port.

8. The nozzle control oil circuit according to claim 1, characterized in that, It also includes a pressure reducing valve, which is arranged between the system oil port and the reversing valve. The oil inlet of the pressure reducing valve is connected to the system oil port, and the oil outlet of the pressure reducing valve is connected to the first oil inlet.

9. A nozzle control oil circuit according to claim 8, characterized in that, It also includes a pressure gauge, which is located at the oil outlet of the pressure reducing valve.

10. An injection molding machine, characterized in that, Includes the nozzle control oil circuit as described in any one of claims 1-9.

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