Pneumatic control loop of forming machine and forming machine

Abstract

The invention provides a pneumatic control loop of a forming machine and the forming machine. The pneumatic control loop comprises an air cylinder; the first branch is communicated with a rod cavity of the air cylinder; the first electromagnetic valve is arranged on the first branch, and a first connecting port and a second connecting port of the first electromagnetic valve are respectively communicated with the first branch; one end of the second branch is communicated with a third connecting port of the first electromagnetic valve; the first pressure reducing valve is arranged on the second branch; at the front section of the descending stroke of the cylinder rod, the first connecting port is communicated with the second connecting port, so that gas in the rod cavity is discharged through the first branch; and at the rear section of the descending stroke of the cylinder rod, the first electromagnetic valve is electrified, and the first connecting port is communicated with the third connecting port, so that gas flowing into the second branch flows into the rod cavity after passing through the first pressure reducing valve and the first electromagnetic valve, and mixed gas is discharged from an overflow port of the first pressure reducing valve. The problem that in the prior art, in the process that a die holder rapidly moves downwards to enter a slurry pool, the liquid level is prone to fluctuating violently, and slurry is splashed is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of pneumatic control, and in particular to a pneumatic control circuit of a molding machine and the molding machine. Background Art

[0002] Complete pulp molding equipment typically includes multiple processes, including pulping, forming, shaping, trimming, and stacking and packaging. During the forming stage, pneumatic control is widely used to achieve the lifting and lowering movement of the forming mold base, primarily due to its simple structure and low cost.

[0003] However, the pneumatic control circuits in existing molding machines mostly use a throttling speed regulation method. When the molding die base is heavy, it is difficult for the cylinder movement to take into account both operating efficiency and control stability. Especially when the die base descends rapidly into the slurry pool, it is easy to cause violent fluctuations in the liquid level, resulting in slurry splashing, which not only affects the molding quality, but also is not conducive to the cleanliness and safety management of the production site. Summary of the Invention

[0004] The main purpose of the present invention is to provide a pneumatic control circuit for a molding machine and a molding machine, so as to solve the problem in the prior art that when the mold base quickly descends into the slurry pool, the liquid level is easily caused to fluctuate violently, resulting in slurry splashing.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a pneumatic control circuit of a molding machine is provided, including a cylinder, the cylinder including a piston and a cylinder rod, the two ends of the cylinder rod are respectively connected to the piston and the mold base of the molding machine to drive the mold base to descend and ascend; the pneumatic control circuit of the molding machine also includes: a first branch, which is connected to the rod chamber of the cylinder; a first solenoid valve, which is arranged in the first branch, and the first connection port and the second connection port of the first solenoid valve are respectively connected to the first branch; a second branch, one end of the second branch is connected to the third connection port of the first solenoid valve; a first pressure reducing valve, which is arranged in the second branch; in the front section of the cylinder rod descending stroke, the first connection port is connected to the second connection port, so that the gas in the rod chamber is discharged through the first branch; in the rear section of the cylinder rod descending stroke, the first solenoid valve is energized, and the first connection port is connected to the third connection port, so that the gas flowing into the second branch flows into the rod chamber after passing through the first pressure reducing valve and the first solenoid valve in sequence, and the mixed gas is discharged from the overflow port of the first pressure reducing valve.

[0006] Furthermore, the pneumatic control circuit of the molding machine also includes: a sensing element, which is arranged in the cylinder and is used to sense the piston; during the descending process of the cylinder rod, when the sensing element senses the piston, the cylinder rod enters the latter part of the descending stroke, and the first solenoid valve is energized.

[0007] Furthermore, the induction element is a magnetic induction switch.

[0008] Furthermore, the pneumatic control circuit of the molding machine further includes: a first speed regulating valve, which is arranged on the first branch and is located on a side of the first solenoid valve away from the rod chamber.

[0009] Furthermore, the pneumatic control circuit of the molding machine also includes: a three-position five-way solenoid valve, including a seventh connection port, an eighth connection port and a ninth connection port, the ninth connection port is used to connect with the air source, and the ninth connection port can be optionally connected with the seventh connection port or the eighth connection port; the end of the first branch away from the rod cavity is connected to the eighth connection port, and the other end of the second branch is connected to the seventh connection port.

[0010] Furthermore, the pneumatic control circuit of the molding machine also includes: a third branch, one end of the third branch is connected to the rodless chamber of the cylinder; the other end of the third branch is connected to the seventh connection port; a second solenoid valve is arranged on the third branch, and the fourth connection port and the fifth connection port of the second solenoid valve are respectively connected to the third branch; a one-way valve and a second pressure reducing valve are arranged in parallel on the third branch and are located on the side of the second solenoid valve away from the rodless chamber; a second speed regulating valve is arranged on the third branch and is located between the second solenoid valve and the rodless chamber; a fourth branch, one end of the fourth branch is connected to the third branch It is connected and located on the side of the second speed regulating valve close to the rodless chamber, and the other end of the fourth branch is connected to the sixth connection port of the second solenoid valve; the third speed regulating valve is arranged on the fourth branch; in the front part of the cylinder rod rising stroke, the fourth connection port is connected with the fifth connection port, so that the gas in the rodless chamber is discharged through the second speed regulating valve, the second solenoid valve, the one-way valve and the second pressure reducing valve; in the rear part of the cylinder rod rising stroke, the second solenoid valve is energized, and the fourth connection port is connected with the sixth connection port, so that the gas in the rodless chamber is discharged through the third speed regulating valve, the second solenoid valve, the one-way valve and the second pressure reducing valve in sequence.

[0011] Furthermore, the pneumatic control circuit of the molding machine also includes: a first induced check valve, which is arranged on the first branch and located between the first solenoid valve and the rod chamber, and the bypass port of the first induced check valve is connected to the seventh connecting port.

[0012] Furthermore, the pneumatic control circuit of the molding machine also includes: a second induced check valve, which is arranged on the third branch and located between the connection point of the fourth branch and the third branch and the rodless cavity, and the bypass port of the second induced check valve is connected to the eighth connection port.

[0013] Furthermore, the pneumatic control circuit of the molding machine also includes a fifth branch and a triplet, the fifth branch is connected to the ninth connection port; the triplet is arranged on the fifth branch, and the triplet includes a filter, a pressure reducing valve and an oil mist collector arranged in sequence along the air inlet direction.

[0014] According to another aspect of the present invention, a molding machine is provided, comprising a mold base and a pneumatic control circuit, wherein the pneumatic control circuit is the pneumatic control circuit described above.

[0015] By applying the technical solution of the present invention, the pneumatic control circuit of the molding machine is equipped with a first branch, a first solenoid valve, a second branch and a first pressure reducing valve so that the front and rear ends of the cylinder rod's descending stroke are exhausted through different paths. The front end discharges the gas in the rod chamber through the first branch, and the rear end controls the first solenoid valve to be energized, so that the first solenoid valve switches from being connected between the first connecting port and the second connecting port to being connected between the first connecting port and the third connecting port; so that the second branch and the first pressure reducing valve introduce gas into the rod chamber being exhausted, which mixes with the original residual gas to generate a certain counter pressure, thereby inhibiting the rapid downward movement of the piston, thereby making the mold base enter the slurry more slowly and steadily, preventing violent fluctuations in the liquid level and splashing of slurry; then, these mixed gases are discharged through the overflow port of the first pressure reducing valve, and the gas will not be released suddenly, but will be released slowly and at a controlled speed to avoid undershooting, thereby solving the problem in the prior art that the liquid level is easily fluctuated violently, resulting in slurry splashing, during the process of the mold base rapidly descending into the slurry pool. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0017] Figure 1 A schematic diagram showing an embodiment of a pneumatic control circuit of a molding machine according to the present invention is shown.

[0018] The above drawings include the following reference numerals:

[0019] 1. Triple piece;

[0020] 2. Three-position five-way solenoid valve;

[0021] 3. Second pressure reducing valve; 4. One-way valve; 5. Second solenoid valve; 6. Third speed regulating valve; 7. Second speed regulating valve; 8. Second induced check valve;

[0022] 9. First induction check valve; 10. First solenoid valve; 11. First speed regulating valve; 12. First pressure reducing valve;

[0023] 13. Cylinder; 131. Piston; 132. Cylinder rod; 133. Rod chamber; 134. Rodless chamber;

[0024] 14. Induction parts;

[0025] 20. First branch road;

[0026] 30, Second Branch Road;

[0027] 40, Third Branch Road;

[0028] 50, Fourth Branch Road;

[0029] 21. Second coil; 22. First coil. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] The present invention provides a pneumatic control circuit for a molding machine, please refer to Figure 1 , including a cylinder 13, the cylinder 13 includes a piston 131 and a cylinder rod 132, the two ends of the cylinder rod 132 are respectively connected to the piston 131 and the mold base of the molding machine to drive the mold base to descend and ascend, the pneumatic control circuit of the molding machine also includes: a first branch 20, which is connected to the rod chamber 133 of the cylinder 13; a first solenoid valve 10, which is arranged on the first branch 20, and the first connection port and the second connection port of the first solenoid valve 10 are respectively connected to the first branch 20; a second branch 30, one end of the second branch 30 is connected to the first solenoid valve 10 The third connection port is connected; the first pressure reducing valve 12 is arranged on the second branch 30; in the front part of the downward stroke of the cylinder rod 132, the first connection port is connected with the second connection port, so that the gas in the rod chamber 133 is discharged through the first branch 20; in the rear part of the downward stroke of the cylinder rod 132, the first solenoid valve 10 is energized, and the first connection port and the third connection port are connected, so that the gas flowing into the second branch 30 flows into the rod chamber 133 after passing through the first pressure reducing valve 12 and the first solenoid valve 10 in turn, and the mixed gas is discharged from the overflow port of the first pressure reducing valve 12.

[0034] The pneumatic control circuit of the molding machine of the present invention is provided with a first branch 20, a first solenoid valve 10, a second branch 30 and a first pressure reducing valve 12, so that the front and rear ends of the cylinder rod 132 are exhausted through different paths during the descending stroke. The front end discharges the gas in the rod chamber 133 through the first branch 20, and the rear end controls the first solenoid valve 10 to be energized, so that the first solenoid valve 10 switches from being connected between the first connection port and the second connection port to being connected between the first connection port and the third connection port; so that the second branch 30 and the first pressure reducing valve 12 introduce gas into the rod chamber 133 being exhausted, mix with the original residual gas, generate a certain back pressure, inhibit the rapid downward movement of the piston 131, thereby making the mold base enter the slurry more slowly and steadily, preventing violent fluctuations in the liquid level and splashing of slurry; then, these mixed gases are discharged through the overflow port of the first pressure reducing valve 12, and the gas will not be released suddenly, but will be released slowly and at a controlled speed to avoid undershooting, thereby solving the problem in the prior art that the liquid level is easily fluctuated violently and slurry splashes during the rapid downward movement of the mold base into the slurry pool.

[0035] Specifically, the first solenoid valve 10 is a two-position three-way valve. Figure 1 As shown, the first connection port of the first solenoid valve 10 is A, the second connection port of the first solenoid valve 10 is P, and the third connection port of the first solenoid valve 10 is R.

[0036] In this embodiment, the pneumatic control circuit of the molding machine also includes: a sensing element 14, which is arranged in the cylinder 13 and is used to sense the piston 131; during the descending process of the cylinder rod 132, when the sensing element 14 senses the piston 131, the cylinder rod 132 enters the latter part of the descending stroke, and the first solenoid valve 10 is energized.

[0037] In specific implementation, the sensor 14 automatically senses the piston position and accurately controls the on and off of the solenoid valve, ensuring the automation and operating accuracy of the molding machine. This improves the response speed and accuracy of the molding machine and reduces errors caused by human operation.

[0038] Optionally, the sensing element 14 is a magnetic induction switch. The application of the magnetic induction switch makes the pneumatic control circuit more intelligent and can sense the movement state of the cylinder in real time without contact.

[0039] In this embodiment, the pneumatic control circuit of the molding machine further includes: a first speed regulating valve 11 , which is arranged on the first branch 20 and located on a side of the first solenoid valve 10 away from the rod chamber 133 .

[0040] During specific implementation, the first speed regulating valve 11 effectively adjusts the air flow speed, improves the movement accuracy of the cylinder, avoids the impact force caused by excessive exhaust, and improves the stability and accuracy of the molding process.

[0041] In this embodiment, the pneumatic control circuit of the molding machine also includes: a three-position five-way solenoid valve 2, including a seventh connection port, an eighth connection port and a ninth connection port, the ninth connection port is used to connect with the air source, and the ninth connection port can be optionally connected with the seventh connection port or the eighth connection port; the end of the first branch 20 away from the rod cavity 133 is connected to the eighth connection port, and the other end of the second branch 30 is connected to the seventh connection port.

[0042] When implementing it specifically, Figure 1 As shown, the three-position five-way solenoid valve 2 includes a seventh connection port A, an eighth connection port B and a ninth connection port P. The three-position five-way solenoid valve 2 achieves more flexible airflow control, making the airflow path switching between the various components of the pneumatic control circuit smoother and more efficient, improving the pneumatic adjustment accuracy during the rising and falling process of the cylinder, and ensuring the reliability of the molding machine during operation.

[0043] In this embodiment, the pneumatic control circuit of the molding machine also includes: a third branch 40, one end of the third branch 40 is connected to the rodless chamber 134 of the cylinder 13; the other end of the third branch 40 is connected to the seventh connection port; a second solenoid valve 5 is arranged on the third branch 40, and the fourth connection port and the fifth connection port of the second solenoid valve 5 are respectively connected to the third branch 40; a one-way valve 4 and a second pressure reducing valve 3 are arranged in parallel on the third branch 40 and are located on the side of the second solenoid valve 5 away from the rodless chamber 134; a second speed regulating valve 7 is arranged on the third branch 40 and is located between the second solenoid valve 5 and the rodless chamber 134; a fourth branch 50, one end of the fourth branch 50 is connected to the third The branch 40 is connected and is located on the side of the second speed control valve 7 close to the rodless chamber 134, and the other end of the fourth branch 50 is connected to the sixth connection port of the second solenoid valve 5; the third speed control valve 6 is arranged on the fourth branch 50; in the front part of the rising stroke of the cylinder rod 132, the fourth connection port is connected with the fifth connection port, so that the gas in the rodless chamber 134 is discharged through the second speed control valve 7, the second solenoid valve 5, the one-way valve 4 and the second pressure reducing valve 3; in the rear part of the rising stroke of the cylinder rod 132, the second solenoid valve 5 is energized, and the fourth connection port is connected with the sixth connection port, so that the gas in the rodless chamber 134 is discharged through the third speed control valve 6, the second solenoid valve 5, the one-way valve 4 and the second pressure reducing valve 3 in sequence.

[0044] In a specific implementation, when the cylinder rod 132 is rising, the induction element 14 senses the piston 131, and the cylinder rod 132 enters the latter part of the rising stroke, and the second solenoid valve 5 is energized. The former part of the rising stroke is the reverse stroke of the latter part of the descending stroke, and the latter part of the rising stroke is the reverse stroke of the former part of the descending stroke.

[0045] Specifically, the second solenoid valve 5 is a two-position three-way valve. Figure 1 As shown, the third connection port of the second solenoid valve 5 is A, the fourth connection port of the second solenoid valve 5 is R, and the fifth connection port of the second solenoid valve 5 is P.

[0046] In this embodiment, the pneumatic control circuit of the molding machine also includes: a first induced check valve 9, which is arranged on the first branch 20 and located between the first solenoid valve 10 and the rod chamber 133, and the bypass port of the first induced check valve 9 is connected to the seventh connecting port.

[0047] During specific implementation, the first induction check valve 9 prevents airflow from reversing, reduces pneumatic system failures caused by unstable airflow, and improves the safety and reliability of the system.

[0048] In this embodiment, the pneumatic control circuit of the molding machine also includes: a second induced check valve 8, which is arranged on the third branch 40 and is located between the connection point of the fourth branch 50 and the third branch 40 and the rodless chamber 134, and the bypass port of the second induced check valve 8 is connected to the eighth connection port.

[0049] In practice, a second induction check valve 8 is positioned on the third branch 40 to ensure that airflow can only flow in the intended direction, preventing backflow that could affect the exhaust and input of gas from the rodless chamber. This second induction check valve 8 further enhances the unidirectional control of airflow, making the exhaust path of the rodless chamber clearer and more reliable, and improving the aerodynamic performance of the molding machine's overall system.

[0050] In specific implementation, as the cylinder drives the mold base downward, the first coil 22 of the neutral pressure-relief, three-position, five-way solenoid valve 2 is energized. The air circuit has two branches: one for air intake, specifically: port A of the three-position, five-way solenoid valve 2, second pressure-reducing valve 3, second solenoid valve 5, second speed regulating valve 7, second induction check valve 8, and rodless chamber 134. The other branch is for air exhaust, specifically: port A of the three-position, five-way solenoid valve 2, and the bypass port of the first induction check valve 9. By pushing open the valve core, air in the rod chamber 133 is routed through the first solenoid valve 10 and then exhausted through the three-position, five-way solenoid valve 2.

[0051] During the first part of the descending stroke, gas in rod chamber 133 is exhausted through first speed regulating valve 11 and three-position, five-way solenoid valve 2. During the latter part of the descending stroke, first solenoid valve 10 is energized, and gas passing through first pressure-reducing valve 12 reaches a higher pressure, mixing with the gas in rod chamber 133. This pressure is then transferred to rod chamber 133, effectively inhibiting piston downward movement. Gas is then exhausted to atmosphere through the overflow port of first pressure-reducing valve 12. Switching between the two descending strokes is initiated by a signal from an inductive switch attached to the cylinder.

[0052] During implementation, as the cylinder drives the mold base upward, the second coil 21 of the 5 / 3-way solenoid valve 2 is energized, creating a two-branch air circuit. One branch serves as the air intake path, specifically connecting: port B of the 5 / 3-way solenoid valve 2, the first speed regulating valve 11, the first solenoid valve 10, the first inductive check valve 9, and the rod chamber 133. The other branch serves as the air exhaust path, specifically connecting: port B of the 5 / 3-way solenoid valve 2, the bypass port of the second inductive check valve 8. This pushes open the valve core, and the air in the rodless chamber 134 is exhausted by the second solenoid valve 5, which selects either the second speed regulating valve 7 or the third speed regulating valve 6 for exhaust.

[0053] During the first part of the ascending stroke, gas in rodless chamber 134 is exhausted through second speed regulating valve 7, check valve 4, second pressure reducing valve 3, and three-position five-way solenoid valve 2. During the second part of the ascending stroke, second solenoid valve 5 is energized, and gas in rodless chamber 134 is exhausted through third speed regulating valve 6, check valve 4, second pressure reducing valve 3, and three-position five-way solenoid valve 2. Switching between the two ascending strokes is initiated by a signal from an inductive switch attached to the cylinder.

[0054] In this embodiment, the pneumatic control circuit of the molding machine also includes a fifth branch and a triplet 1, and the fifth branch is connected to the ninth connection port; the triplet 1 is arranged on the fifth branch, and the triplet 1 includes a filter, a pressure reducing valve and an oil mist collector arranged in sequence along the air inlet direction.

[0055] In practice, the triplex 1 includes a filter, a pressure reducing valve, and a lubricator, ensuring cleanliness, stability, and lubrication of the air supply entering the pneumatic control circuit. It effectively removes impurities from the air, regulates air pressure, and provides proper lubrication, protecting all components in the pneumatic system. This triplex 1 improves air supply quality, protects the molding machine's pneumatic components, reduces wear and failure, and enhances the durability of the entire system. This improves the stability of the pneumatic system and reduces maintenance costs.

[0056] The pneumatic control circuit of the present invention solves the technical problem of quickly injecting slurry into a large-mass forming die base and splashing slurry, thereby ensuring both production efficiency and cleanliness of the production site.

[0057] The pneumatic control circuit of the present invention travels in the direction of gravity, and its control branch air circuit, the intake air is then reduced in pressure by a pressure reducing valve, and there are two options for exhaust: one is to return to the atmosphere through the overflow port of the pressure reducing valve. The gas coming from the pressure reducing valve has a higher pressure and can effectively inhibit the operation of the piston; the other is to return to the atmosphere through the speed regulating valve.

[0058] The pneumatic control circuit of the present invention is characterized by adopting exhaust throttling speed regulation; the raising and lowering circuits each have two throttling amount options, and a three-port two-position solenoid valve is used to realize different throttling amount selections; the cylinder air inlet is connected to an induced check valve; the air sources of the raising and lowering circuits are reduced in pressure by different pressure reducing valves; during the descending stroke, the air source is reduced in pressure and the piston rod side inhibits the piston operation.

[0059] The present invention also provides a molding machine, comprising a mold base and a pneumatic control circuit, wherein the pneumatic control circuit is the pneumatic control circuit of the above embodiment.

[0060] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0061] The pneumatic control circuit of the molding machine of the present invention is provided with a first branch 20, a first solenoid valve 10, a second branch 30 and a first pressure reducing valve 12, so that the front and rear ends of the cylinder rod 132 are exhausted through different paths during the descending stroke. The front end discharges the gas in the rod chamber 133 through the first branch 20, and the rear end controls the first solenoid valve 10 to be energized, so that the first solenoid valve 10 switches from being connected between the first connection port and the second connection port to being connected between the first connection port and the third connection port; so that the second branch 30 and the first pressure reducing valve 12 introduce gas into the rod chamber 133 being exhausted, mix with the original residual gas, generate a certain back pressure, inhibit the rapid downward movement of the piston 131, thereby making the mold base enter the slurry more slowly and steadily, preventing violent fluctuations in the liquid level and splashing of slurry; then, these mixed gases are discharged through the overflow port of the first pressure reducing valve 12, and the gas will not be released suddenly, but will be released slowly and at a controlled speed to avoid undershooting, thereby solving the problem in the prior art that the liquid level is easily fluctuated violently and slurry splashes during the rapid downward movement of the mold base into the slurry pool.

[0062] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0063] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0064] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A pneumatic control circuit for a molding machine, comprising a cylinder (13), wherein the cylinder (13) comprises a piston (131) and a cylinder rod (132), wherein both ends of the cylinder rod (132) are respectively connected to the piston (131) and a mold base of the molding machine to drive the mold base to descend and ascend; wherein: The pneumatic control circuit of the molding machine also includes: A first branch (20) is communicated with the rod chamber (133) of the cylinder (13); a first solenoid valve (10) disposed on the first branch (20), wherein a first connection port and a second connection port of the first solenoid valve (10) are respectively connected to the first branch (20); a second branch (30), one end of the second branch (30) being connected to the third connection port of the first solenoid valve (10); a first pressure reducing valve (12), disposed on the second branch (30); In the front section of the descending stroke of the cylinder rod (132), the first connecting port is connected to the second connecting port so that the gas in the rod chamber (133) is discharged through the first branch (20); in the rear section of the descending stroke of the cylinder rod (132), the first solenoid valve (10) is energized, and the first connecting port is connected to the third connecting port so that the gas flowing into the second branch (30) flows into the rod chamber (133) after passing through the first pressure reducing valve (12) and the first solenoid valve (10) in sequence, and the mixed gas is discharged from the overflow port of the first pressure reducing valve (12).

2. The pneumatic control circuit of the molding machine according to claim 1, characterized in that: The pneumatic control circuit of the molding machine also includes: a sensing element (14), disposed on the cylinder (13) and used for sensing the piston (131); During the descending process of the cylinder rod (132), when the sensing element (14) senses the piston (131), the cylinder rod (132) enters the latter part of the descending stroke, and the first solenoid valve (10) is energized.

3. The pneumatic control circuit of the molding machine according to claim 2, characterized in that: The induction component (14) is a magnetic induction switch.

4. The pneumatic control circuit of the molding machine according to claim 1, characterized in that: The pneumatic control circuit of the molding machine also includes: The first speed regulating valve (11) is arranged on the first branch (20) and is located on a side of the first solenoid valve (10) away from the rod chamber (133).

5. The pneumatic control circuit of the molding machine according to claim 1, characterized in that: The pneumatic control circuit of the molding machine also includes: A three-position, five-way solenoid valve (2) comprises a seventh connection port, an eighth connection port and a ninth connection port, wherein the ninth connection port is used to communicate with an air source, and the ninth connection port can be optionally communicated with the seventh connection port or the eighth connection port; an end of the first branch (20) away from the rod chamber (133) is connected to the eighth connection port, and the other end of the second branch (30) is connected to the seventh connection port.

6. The pneumatic control circuit of the molding machine according to claim 5, characterized in that: The pneumatic control circuit of the molding machine also includes: a third branch (40), one end of the third branch (40) being in communication with the rodless chamber (134) of the cylinder (13); and the other end of the third branch (40) being in communication with the seventh connection port; a second solenoid valve (5) disposed on the third branch (40), wherein the fourth connection port and the fifth connection port of the second solenoid valve (5) are respectively connected to the third branch (40); A one-way valve (4) and a second pressure reducing valve (3) are arranged in parallel on the third branch (40) and are located on a side of the second solenoid valve (5) away from the rodless chamber (134); a second speed regulating valve (7) disposed in the third branch (40) and located between the second solenoid valve (5) and the rodless chamber (134); a fourth branch (50), one end of the fourth branch (50) being in communication with the third branch (40) and being located on a side of the second speed regulating valve (7) close to the rodless chamber (134), and the other end of the fourth branch (50) being in communication with the sixth connection port of the second solenoid valve (5); a third speed regulating valve (6), arranged on the fourth branch (50); In the front section of the rising stroke of the cylinder rod (132), the fourth connection port is connected to the fifth connection port, so that the gas in the rodless chamber (134) is discharged through the second speed regulating valve (7), the second solenoid valve (5), the one-way valve (4) and the second pressure reducing valve (3); in the rear section of the rising stroke of the cylinder rod (132), the second solenoid valve (5) is energized, and the fourth connection port is connected to the sixth connection port, so that the gas in the rodless chamber (134) is discharged through the third speed regulating valve (6), the second solenoid valve (5), the one-way valve (4) and the second pressure reducing valve (3) in sequence.

7. The pneumatic control circuit of the molding machine according to claim 5, characterized in that: The pneumatic control circuit of the molding machine also includes: A first induction check valve (9) is provided on the first branch (20) and is located between the first solenoid valve (10) and the rod chamber (133); a bypass port of the first induction check valve (9) is connected to the seventh connection port.

8. The pneumatic control circuit of the molding machine according to claim 6, characterized in that: The pneumatic control circuit of the molding machine also includes: A second induction check valve (8) is provided on the third branch (40) and is located between the connection point of the fourth branch (50) and the third branch (40) and the rodless chamber (134), and a bypass port of the second induction check valve (8) is connected to the eighth connection port.

9. The pneumatic control circuit of the molding machine according to claim 5, characterized in that: The pneumatic control circuit of the molding machine further comprises a fifth branch and a triplet (1), wherein the fifth branch is connected to the ninth connection port; the triplet (1) is arranged on the fifth branch, and the triplet (1) comprises a filter, a pressure reducing valve and an oil mist collector which are sequentially arranged along the air inlet direction.

10. A molding machine, comprising a die base and a pneumatic control circuit, characterized in that: The pneumatic control circuit is the pneumatic control circuit according to any one of claims 1 to 9.

Images