A mold locking and pressure relief oil circuit for an injection molding machine

Abstract

The utility model relates to the technical field of hydraulic circuit, and specifically discloses a mold locking pressure relief oil circuit of injection molding machine, including first pressure relief circuit, first pressure relief circuit includes cartridge valve, first electromagnetic reversing valve, first damping, second damping and third damping, cartridge valve has first import, first export and pilot chamber, first import is linked with the rod cavity of mold locking oil cylinder, first export is linked with the rodless cavity of mold locking oil cylinder, and the pilot chamber can be communicated with the oil tank through first electromagnetic reversing valve, first damping has first variable oil port and second variable oil port, first variable oil port is communicated with the pilot chamber, second variable oil port is communicated with the oil inlet of first electromagnetic reversing valve, second damping and third damping are provided between the rod cavity of mold locking oil cylinder and second variable oil port in parallel, then the control oil of cartridge valve pilot chamber adopts double channel, the probability that second damping and third damping are blocked at the same time is smaller, and the risk that cartridge valve cannot be closed due to oil cleanliness can be reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of hydraulic circuits, and specifically to a mold-locking pressure relief oil circuit for an injection molding machine. Background Technology

[0002] The high-pressure clamping action of a two-platen injection molding machine will establish a high clamping pressure in the clamping cylinder. Therefore, it is particularly important to smoothly release the clamping pressure after the high-pressure clamping action.

[0003] In existing technology, the hydraulic oil in the rod chamber of the mold-locking cylinder is usually depressurized through a cartridge valve. The control circuit of the cartridge valve is typically controlled by a damper, but this damper control is easily clogged by impurities in the oil, causing the cartridge valve to malfunction and fail to open and close properly. To solve this problem, a mold-locking pressure relief circuit, as disclosed in patent number 2018116446006, utilizes an electromagnetic directional valve V62 instead of a damper to control the control circuit of the cartridge valve V59. When the cartridge valve V59 needs to open... Closing the solenoid directional valve V62 disconnects this control oil circuit. When the cartridge valve V59 needs to be closed, opening the solenoid directional valve V62 opens this control oil circuit. This control method avoids the situation where the cartridge valve V59 cannot be closed or opened due to changes in the flow capacity of the secondary control oil circuit caused by the cleanliness. However, using the solenoid directional valve V62 instead of the damper will significantly increase the cost. Moreover, when depressurizing, the high-pressure oil is directly released into the oil tank. The high-pressure oil will impact the oil tank, causing impurities in the oil tank to tumble and reducing the cleanliness of the oil. Utility Model Content

[0004] This utility model addresses the aforementioned problems and aims to provide a mold-locking pressure relief oil circuit for an injection molding machine. By setting a dual-damping control oil circuit, the risk of blockage causing the cartridge valve to fail to open or close smoothly can be reduced. At the same time, the oil flows to the rodless chamber, avoiding impact on the oil in the oil tank.

[0005] To achieve the above objectives, this utility model provides a mold-locking pressure relief oil circuit for an injection molding machine, used to relieve pressure in the rod-side chamber of the mold-locking cylinder. The pressure relief oil circuit includes a first pressure relief circuit, and the rod-side chamber of the mold-locking cylinder can be connected to the rodless chamber of the mold-locking cylinder through the first pressure relief circuit. The first pressure relief circuit includes a cartridge valve, a first solenoid directional valve, a first damper, a second damper, and a third damper. The cartridge valve has a first inlet, a first outlet, and a pilot chamber. The first inlet is connected to the rod chamber of the mold-locking cylinder, and the first outlet is connected to the rodless chamber of the mold-locking cylinder. The pilot chamber can be connected to the oil tank through the first solenoid directional valve. The first damper has a first variable port and a second variable port. The first variable port is connected to the pilot chamber, and the second variable port is connected to the inlet of the first solenoid directional valve. The second damper and the third damper are connected in parallel between the rod chamber of the mold-locking cylinder and the second variable oil port.

[0006] According to the above-described mold-locking pressure relief oil circuit of an injection molding machine, the oil inlets of the second damper and the third damper are both connected to the rod chamber of the mold-locking cylinder, and the oil outlets of the second damper and the third damper are both connected to the second variable oil port.

[0007] According to the above-described mold-locking pressure relief oil circuit of an injection molding machine, the first pressure relief circuit further includes a fourth damper, the oil outlet of the fourth damper is connected to the second variable oil port, and the oil outlets of the second damper and the third damper are both connected to the oil inlet of the fourth damper.

[0008] According to the above-described mold-locking and pressure-relief oil circuit of an injection molding machine, the first electromagnetic reversing valve is equipped with a first electromagnet. When the first electromagnet is energized, the oil inlet and outlet of the first electromagnetic reversing valve are connected.

[0009] The mold-locking pressure relief oil circuit of the injection molding machine described above further includes a second pressure relief circuit. The second pressure relief circuit includes a second solenoid directional valve. The oil inlet of the second solenoid directional valve is connected to the rod chamber of the mold-locking cylinder, and the oil outlet of the second solenoid directional valve is connected to the rodless chamber of the mold-locking cylinder.

[0010] According to the above-described mold-locking pressure relief oil circuit of an injection molding machine, the flow channel diameter of the second electromagnetic reversing valve is smaller than the flow channel diameter of the cartridge valve.

[0011] According to the above-described mold-locking pressure relief oil circuit of an injection molding machine, the second pressure relief circuit further includes a fifth damper, which is located between the rod chamber of the mold-locking cylinder and the oil inlet of the second electromagnetic reversing valve.

[0012] According to the above-described injection molding machine clamping pressure relief oil circuit, a first pipe is provided between the rod chamber of the clamping cylinder and the first inlet of the cartridge valve, the oil inlet of the second electromagnetic reversing valve is connected to the first pipe through the second pipe, and the fifth damper is located on the second pipe.

[0013] According to the above-described injection molding machine mold locking and pressure relief oil circuit, the second electromagnetic reversing valve is equipped with a second electromagnet. When the second electromagnet is energized, the oil inlet and outlet of the second electromagnetic reversing valve are connected.

[0014] The above-described mold-locking pressure relief oil circuit for an injection molding machine further includes a pressure gauge and a pressure sensor. The pressure gauge and the pressure sensor are located on the rod-side of the mold-locking cylinder and are used to measure the pressure inside the rod-side of the mold-locking cylinder.

[0015] This utility model has the following beneficial effects: 1. The second and third dampers are set in parallel, that is, the control oil can move to the first damper through the second and third dampers, and then move to the pilot chamber of the cartridge valve through the first damper. The probability of the second and third dampers being blocked at the same time is low. Without significantly increasing the cost, the probability of blockage in the control oil circuit of the cartridge valve can be effectively reduced, ensuring the normal use of the cartridge valve. 2. After the hydraulic oil in the rod chamber of the mold-locking cylinder is depressurized, it returns to its rodless chamber to achieve differential pressure relief, thereby preventing high-pressure hydraulic oil from directly impacting the oil in the tank and causing the oil in the tank to become turbid. 3. A second pressure relief circuit is also provided for early pressure relief. Since the flow channel of the second solenoid directional valve is smaller than that of the cartridge valve, the cartridge valve can be closed and the second solenoid directional valve can be opened during early pressure relief. Due to its smaller flow channel, the flow rate of hydraulic oil can be reduced, thus preventing high pressure from impacting the rodless chamber. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall circuit of an embodiment.

[0017] In the picture: 100. First pressure relief circuit; 110. Cartridge valve; 120. First solenoid directional valve; 121. First electromagnet; 130. First damper; 140. Second damper; 150. Third damper; 160. Fourth damper; 200. Second pressure relief circuit; 210. Second solenoid directional valve; 211. Second electromagnet; 220. Fifth damper; 300. Pressure gauge; 400. Pressure sensor; 500. Mold clamping cylinder. Detailed Implementation

[0018] 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.

[0019] like Figure 1As shown, a mold-locking pressure relief oil circuit for an injection molding machine includes a first pressure relief circuit 100 and a second pressure relief circuit 200, used to relieve pressure in the rod chamber of the mold-locking cylinder 500. The rod chamber of the mold-locking cylinder 500 can be connected to the rodless chamber of the same cylinder through the first pressure relief circuit 100 or the second pressure relief circuit 200. That is, the mold-locking cylinder 500 uses differential pressure relief during the pressure relief process, which can absorb part of the impact of high-pressure oil using devices such as hoses and pistons, reducing vibration. At the same time, the high-pressure oil being relieved will not flow into the oil tank, avoiding the problem of decreased cleanliness of hydraulic oil in the oil tank due to oil impact.

[0020] The first pressure relief circuit 100 includes a cartridge valve 110, a first solenoid directional valve 120, a first damper 130, a second damper 140, and a third damper 150. The cartridge valve 110 has a first inlet, a first outlet, and a pilot chamber. The first inlet is connected to the rod-side chamber of the mold-locking cylinder 500, and the first outlet is connected to the rodless chamber of the mold-locking cylinder 500. The pilot chamber can be connected to an oil tank via the first solenoid directional valve 120. The first damper 130 has a first variable port and a second variable port. The first variable port is connected to the pilot chamber, and the second variable port is connected to the inlet of the first solenoid directional valve 120. The second damper 140 and the third damper 150 are connected in parallel between the rod-side chamber and the second variable port of the mold-locking cylinder 500. The pilot oil pressure in the pilot chamber of the cartridge valve 110 can control its opening. When the cartridge valve 110 is open, the mold-locking cylinder 500... The rod chamber of cylinder 500 can discharge oil to the rodless chamber of cylinder 500 through cartridge valve 110. When cartridge valve 110 is open, the first solenoid directional valve 120 is required to open. The pilot oil in the pilot chamber of cartridge valve 110 is discharged through the first solenoid directional valve 120. When cartridge valve 110 needs to be closed, the first solenoid directional valve 120 is closed. Part of the hydraulic oil discharged from the rod chamber of cylinder 500 enters the pilot chamber of cartridge valve 110 through two channels: the second damper 140 to the first damper 130 or the third damper 150 to the first damper 130, thereby closing cartridge valve 110. Compared with a single control channel, the probability of the second damper 140 and the third damper 150 being blocked at the same time is smaller when using dual control channels. This can reduce the risk that cartridge valve 110 cannot be opened or closed due to oil cleanliness. Moreover, multiple dampers have lower costs and do not require a significant increase in costs.

[0021] Furthermore, the oil inlets of the second damper 140 and the third damper 150 are both connected to the rod chamber of the mold-locking cylinder 500, and the oil outlets of the second damper 140 and the third damper 150 are both connected to the second variable oil port. That is, as long as one of the second damper 140 and the third damper 150 is not blocked, the control oil of the cartridge valve 110 can flow normally. Moreover, the hydraulic oil coming out of the mold-locking cylinder 500 first passes through the second damper 140 or the third damper 150. If there are impurities, they will also remain on the second damper 140 or the third damper 150 and will not move with the oil to the first damper 130, thus not blocking the first damper 130.

[0022] Furthermore, the first pressure relief circuit 100 also includes a fourth damper 160. The oil outlet of the fourth damper 160 is connected to the second variable oil port. The oil outlets of the second damper 140 and the third damper 150 are both connected to the oil inlet of the fourth damper 160. An additional fourth damper 160 is added to further increase the resistance in the control oil circuit, ensure the smooth closing of the cartridge valve 110, and at the same time further block impurities in the oil to prevent the first damper 130 from being blocked, thereby preventing the cartridge valve 110 from failing to open normally.

[0023] In this embodiment, during the opening of the cartridge valve 110, the pilot oil in its pilot chamber is discharged to the oil tank through the first damper 130 and the first solenoid directional valve 120. The function of the first damper 130 is to provide damping and deceleration for the pilot oil, ensuring that the cartridge valve 110 opens more smoothly. During the cartridge closing process, part of the hydraulic oil in the rod chamber of the mold locking cylinder 500 is used as pilot oil and enters the fourth damper 160 through the second damper 140 or the third damper 150. Then, it enters the pilot chamber of the cartridge valve 110 through the first damper 130, thus closing it. The function of the second damper 140 and the third damper 150 is to provide a dual flow path for the pilot oil to enter, avoiding blockage of the entire control oil circuit due to blockage of one of them, and also playing a preliminary cleaning role. The fourth damper 160 further provides damping force, making the cartridge valve 110 close stably, and at the same time performing secondary cleaning to prevent the first damper 130 from being blocked.

[0024] Of course, in order to control the opening and closing of the first electromagnetic directional valve 120, a first electromagnet 121 is provided on the first electromagnetic directional valve 120. When the first electromagnet 121 is energized, the oil inlet and oil outlet of the first electromagnetic directional valve 120 are connected. By controlling the energization of the first electromagnet 121, the opening or closing of the first electromagnetic directional valve 120 can be controlled.

[0025] The second pressure relief circuit 200 includes a second solenoid directional valve 210. The oil inlet of the second solenoid directional valve 210 is connected to the rod chamber of the mold-locking cylinder 500, and the oil outlet of the second solenoid directional valve 210 is connected to the rodless chamber of the mold-locking cylinder 500. That is, in addition to pressure relief through the cartridge valve 110, the mold-locking cylinder 500 can also be pressure-relieved through the second solenoid directional valve 210. Either one can be selected.

[0026] Furthermore, in this embodiment, the flow channel diameter of the second electromagnetic directional valve 210 is smaller than that of the cartridge valve 110. Therefore, the flow rate of hydraulic oil through the second electromagnetic directional valve 210 is smaller, and the impact force is also smaller. Thus, the second electromagnetic directional valve 210 can be used for early pressure relief. The hydraulic oil pressure is relatively high during early pressure relief. If the pressure is directly relieved through the cartridge valve 110, it may cause a large impact in the rodless chamber of the mold-locking cylinder 500, which will cause abnormal noise. However, by relieving pressure through the second electromagnetic directional valve 210, the impact and noise can be reduced. After early pressure relief, the cartridge valve 110 is used for further pressure relief to ensure pressure relief efficiency.

[0027] Furthermore, the second pressure relief circuit 200 also includes a fifth damper 220, which is located between the rod chamber of the mold-locking cylinder 500 and the oil inlet of the second solenoid directional valve 210. The fifth damper 220 is used to provide a damping effect for the second pressure relief circuit 200, so as to prevent the hydraulic oil in the rod chamber of the mold-locking cylinder 500 from rushing out quickly during early pressure relief, thereby achieving smooth pressure relief.

[0028] Furthermore, a first pipe is provided between the rod chamber of the mold-locking cylinder 500 and the first inlet of the cartridge valve 110. The oil inlet of the second solenoid directional valve 210 is connected to the first pipe through the second pipe. The fifth damper 220 is located on the second pipe, and one oil port of the second damper 140 is connected to the first pipe, and one oil port of the third damper 150 is connected to the second pipe. When the second solenoid directional valve 210 is opened, the pilot oil in the pilot chamber of the cartridge valve 110 needs to pass through the first damper 130, the fourth damper 160, and the third damper 150 in sequence before it can flow out from the second solenoid directional valve 210. The flow capacity of this channel is much smaller than the flow capacity of the channel from the rod chamber of the mold-locking cylinder 500 to the second solenoid directional valve 210. Therefore, when the second solenoid directional valve 210 is opened, the pilot oil in the pilot chamber of the cartridge valve 110 will not flow out, and the cartridge valve 110 will not be opened.

[0029] Of course, in order to control the opening and closing of the second electromagnetic reversing valve 210, a second electromagnet 211 is provided on the second electromagnetic reversing valve 210. When the second electromagnet 211 is energized, the oil inlet and oil outlet of the second electromagnetic reversing valve 210 are connected.

[0030] To ensure the safety of the mold clamping cylinder 500, a pressure gauge 300 and a pressure sensor 400 are also included. The pressure gauge 300 and the pressure sensor 400 are located on the rod chamber side of the mold clamping cylinder 500 and are used to measure the pressure in the rod chamber of the mold clamping cylinder 500. The pressure in the rod chamber of the mold clamping cylinder 500 is monitored in real time. When the pressure exceeds or approaches the safety threshold, the cartridge valve 110 and / or the second solenoid directional valve 210 can be controlled to open, thereby improving its safety performance.

[0031] In this embodiment, a mold-locking pressure relief oil circuit for an injection molding machine is disclosed, including a first pressure relief circuit 100. The first pressure relief circuit 100 includes a cartridge valve 110, a first solenoid directional valve 120, a first damper 130, a second damper 140, and a third damper 150. The cartridge valve 110 has a first inlet, a first outlet, and a pilot chamber. The first inlet is connected to the rod-side chamber of the mold-locking cylinder 500, and the first outlet is connected to the rodless chamber of the mold-locking cylinder 500. The pilot chamber can be connected to an oil tank through the first solenoid directional valve 120. The first damper 130 has a first variable oil port and a second variable oil port. The variable oil port is connected to the pilot chamber, and the second variable oil port is connected to the oil inlet of the first electromagnetic reversing valve 120. The second damper 140 and the third damper 150 are connected in parallel between the rod chamber of the mold-locking cylinder 500 and the second variable oil port. Thus, the pilot oil control oil circuit of the cartridge valve 110 is divided into two lines: the second damper 140 to the first damper 130 and the third damper 150 to the first damper 130. Compared with the single control channel, the probability of the second damper 140 and the third damper 150 being blocked at the same time is smaller, which can reduce the risk that the cartridge valve 110 cannot be opened or closed due to the cleanliness of the oil.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 scope of protection claimed by this utility model.

Claims

1. A mold-locking pressure relief oil circuit for an injection molding machine, used to relieve pressure in the rod-side chamber of the mold-locking cylinder, characterized in that, The pressure relief oil circuit includes a first pressure relief circuit, and the rod-side chamber of the mold-locking cylinder can be connected to the rodless chamber of the mold-locking cylinder through the first pressure relief circuit; The first pressure relief circuit includes a cartridge valve, a first solenoid directional valve, a first damper, a second damper, and a third damper. The cartridge valve has a first inlet, a first outlet, and a pilot chamber. The first inlet is connected to the rod chamber of the mold-locking cylinder, and the first outlet is connected to the rodless chamber of the mold-locking cylinder. The pilot chamber can be connected to the oil tank through the first solenoid directional valve. The first damper has a first variable port and a second variable port. The first variable port is connected to the pilot chamber, and the second variable port is connected to the inlet of the first solenoid directional valve. The second damper and the third damper are connected in parallel between the rod chamber of the mold-locking cylinder and the second variable oil port.

2. The mold-locking pressure relief oil circuit of an injection molding machine according to claim 1, characterized in that, The oil inlets of the second damper and the third damper are both connected to the rod chamber of the mold-locking cylinder, and the oil outlets of the second damper and the third damper are both connected to the second variable oil port.

3. The mold-locking pressure relief oil circuit of an injection molding machine according to claim 2, characterized in that, The first pressure relief circuit also includes a fourth damper, the oil outlet of which is connected to the second variable oil port, and the oil outlets of the second damper and the third damper are both connected to the oil inlet of the fourth damper.

4. The mold-locking pressure relief oil circuit of an injection molding machine according to claim 1, characterized in that, The first electromagnetic reversing valve is equipped with a first electromagnet. When the first electromagnet is energized, the oil inlet and outlet of the first electromagnetic reversing valve are connected.

5. The mold-locking pressure relief oil circuit of an injection molding machine according to claim 1, characterized in that, It also includes a second pressure relief circuit, which includes a second solenoid directional valve. The oil inlet of the second solenoid directional valve is connected to the rod chamber of the mold-locking cylinder, and the oil outlet of the second solenoid directional valve is connected to the rodless chamber of the mold-locking cylinder.

6. The mold-locking pressure relief oil circuit of an injection molding machine according to claim 5, characterized in that, The flow channel diameter of the second electromagnetic reversing valve is smaller than that of the cartridge valve.

7. The mold-locking pressure relief oil circuit of an injection molding machine according to claim 5, characterized in that, The second pressure relief circuit also includes a fifth damper, which is located between the rod chamber of the mold-locking cylinder and the oil inlet of the second electromagnetic reversing valve.

8. The mold-locking pressure relief oil circuit of an injection molding machine according to claim 7, characterized in that, A first pipe is provided between the rod chamber of the mold-locking cylinder and the first inlet of the cartridge valve. The oil inlet of the second electromagnetic reversing valve is connected to the first pipe through a second pipe. The fifth damper is located on the second pipe.

9. The mold-locking pressure relief oil circuit of an injection molding machine according to claim 5, characterized in that, The second electromagnetic reversing valve is equipped with a second electromagnet. When the second electromagnet is energized, the oil inlet and outlet of the second electromagnetic reversing valve are connected.

10. The mold-locking pressure relief oil circuit of an injection molding machine according to claim 1, characterized in that, It also includes a pressure gauge and a pressure sensor, which are located on the rod-side of the mold-locking cylinder and are used to measure the pressure inside the rod-side of the mold-locking cylinder.

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