Compression molding equipment and its mold opening and locking hydraulic control system and control method

Abstract

The present invention discloses a compression molding device and a mold opening and locking hydraulic control system and control method thereof, which relate to the field of hydraulic control. The mold opening and locking hydraulic control system comprises: a mold opening and locking hydraulic cylinder (1), a mold opening and locking main valve (V1) and a pre-mold opening oil return circuit (6). The pre-mold opening oil return circuit (6) is provided with a pre-mold opening oil return control valve so that the pre-mold opening oil return control valve can control the mold opening and locking hydraulic cylinder (1) to return oil to an oil tank through the pre-mold opening oil return circuit (6). The mold opening and locking hydraulic control system, the compression molding device and the mold control method of the compression molding device of the present invention are low in cost and can realize the function that the deformation of the mold plate can be effectively and quickly released during the mold opening process.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic control, and in particular to a mold opening and locking hydraulic control system, compression molding equipment and a mold control method for the compression molding equipment. Background Art

[0002] When the mold opening and locking system of a general injection molding machine realizes the mold opening and locking action, based on the flow amplification characteristics of the oil cylinder during mold opening and the requirements for the action cycle, the mold opening and locking valve usually adopts a larger electro-hydraulic directional valve. However, due to the switch characteristics of the electro-hydraulic directional valve and the need for a pilot pressure of 10~15bar during control, during the mold opening process, not only can the deformation of the template after high-pressure mold locking not be properly released, but also active braking cannot be achieved, resulting in vibration during mold opening and locking, and the mold opening position accuracy and mold opening time cycle are very unsatisfactory, so it can only meet low-end production requirements. When the requirements for mold opening and locking are high, most of the injection molding machines use high-performance proportional directional valves in the mold opening and locking system. Although this can solve the problems in the above-mentioned mold opening and locking process, if the valve core opening of the proportional directional valve is improperly set, cavitation will occur during the mold opening process. In addition, the use of high-performance proportional directional valves usually requires the commissioning personnel to have a high level of professional operation, and the configuration and cost of high-performance proportional directional valves and their control hardware are high, which reduces the cost performance of the whole machine. Summary of the invention

[0003] The object of the present invention is to provide a low-cost mold opening and locking hydraulic control system, a compression molding device and a mold control method for the compression molding device that can effectively and quickly release the deformation of the mold plate and the machine hinge during the pre-mold opening process.

[0004] In order to achieve the above object, the present invention provides a mold opening and locking hydraulic control system, the mold opening and locking hydraulic control system comprising:

[0005] A mold opening and locking hydraulic cylinder, which is used to control the mold opening and locking actions;

[0006] A main valve for opening and locking the mold, a first working oil circuit and a second working oil circuit are connected between the main valve for opening and locking the mold and the hydraulic cylinder for opening and locking the mold, the main valve for opening and locking the mold can be selectively controlled to be in a neutral position, a first switching position or a second switching position, when the main valve for opening and locking the mold is in a neutral position, the first working oil circuit and the second working oil circuit are respectively blocked from the main oil inlet circuit or the main oil return circuit; when the main valve for opening and locking the mold is in a first switching position, the first working oil circuit and the second working oil circuit are respectively connected to the main oil inlet circuit and the main oil return circuit; when the main valve for opening and locking the mold is in a second switching position, the first working oil circuit and the second working oil circuit are respectively connected to the main oil return circuit and the main oil inlet circuit; and,

[0007] A pre-mold opening oil return circuit is provided with a pre-mold opening oil return control valve and is connected to the first working oil circuit so that it can be controlled by the pre-mold opening oil return control valve to allow the mold opening and locking hydraulic cylinder to return oil to the oil tank through the pre-mold opening oil return circuit when the mold opening and locking main valve is in the middle position.

[0008] Optionally, the mold opening and locking hydraulic control system includes a pre-mold opening oil replenishment circuit connected to the second working oil circuit, the pre-mold opening oil replenishment circuit is provided with a pre-mold opening oil replenishment valve, and is configured to replenish oil to another oil chamber of the mold opening and locking hydraulic cylinder through the pre-mold opening oil replenishment circuit while one oil chamber of the mold opening and locking hydraulic cylinder returns oil through the pre-mold opening oil return circuit.

[0009] Furthermore, the mold opening and locking hydraulic cylinder may include a rodless chamber and a rod chamber, and the mold opening and locking main valve includes a main valve oil inlet connected to the main oil inlet oil circuit, a main valve oil return port connected to the main oil return oil circuit, a first working oil port connected to the rodless chamber through the first working oil circuit, and a second working oil port connected to the rod chamber through the second working oil circuit, wherein:

[0010] When the mold opening and locking main valve is in the middle position, the main valve oil inlet, the main valve oil return port, the first working oil port and the second working oil port are all blocked;

[0011] When the mold opening and locking main valve is in the first switching position, the main valve oil inlet is connected to the first working oil port, and the second working oil port is connected to the main valve oil return port;

[0012] When the mold opening and locking main valve is in the second switching position, the main valve oil inlet is communicated with the second working oil port, and the first working oil port is communicated with the main valve oil return port.

[0013] Furthermore, the pre-mold opening oil return control valve includes a switch valve for controlling the on-off of the pre-mold opening oil return oil circuit.

[0014] Furthermore, the pre-opening mold return oil control valve also includes a first cartridge valve connected in parallel with the switch valve, the control oil port of the first cartridge valve is connected to a first pilot control oil circuit, and the first pilot control oil circuit is provided with a pilot proportional overflow valve for controlling the on and off of the first cartridge valve.

[0015] Optionally, a damping valve is provided on the pre-mold return oil line.

[0016] In some embodiments, the mold opening and locking hydraulic control system may also include an express valve group unit arranged on the main return oil circuit, the express valve group unit includes a second cartridge valve, the control oil circuit of the second cartridge valve is connected to a second pilot control oil circuit, and the second pilot control oil circuit is provided with a pilot control directional valve for controlling the on and off of the second cartridge valve.

[0017] Optionally, a one-way valve with a forward oil port facing the main oil return circuit is connected between the main oil inlet circuit and the main oil return circuit.

[0018] Correspondingly, the present invention also provides a compression molding device, which includes the above-mentioned mold opening and locking hydraulic control system.

[0019] Correspondingly, the present invention also provides a mold control method for a compression molding device, including a mold locking step, a pre-mold opening step and a mold opening step. In the pre-mold opening step, the mold opening and locking main valve used to control the mold opening and locking action is in a middle position, and the mold opening and locking hydraulic cylinder returns oil to the oil tank through the pre-mold opening return oil circuit.

[0020] Optionally, the pre-mold return oil control valve disposed on the pre-mold return oil circuit includes a first cartridge valve, a control oil port of the first cartridge valve is connected to a first pilot control oil circuit, and a pilot proportional relief valve for controlling the on-off of the first cartridge valve is provided on the first pilot control oil circuit, and the mold opening step includes:

[0021] S1. A high-speed mold opening step, in which the mold opening and locking hydraulic cylinder returns oil to the oil tank through the first cartridge valve in the pre-mold opening oil return circuit.

[0022] Furthermore, the mold opening step may include:

[0023] S2. A mold opening and braking sub-step, in which the mold opening and locking hydraulic cylinder throttles the oil back to the oil tank through the pre-mold opening oil return oil circuit.

[0024] The mold opening and locking hydraulic control system of the present invention is provided with a pre-mold opening oil return circuit including a pre-mold opening oil return control valve. When the mold opening and locking hydraulic control system is in the pre-mold opening step, the pre-mold opening oil return control valve is controlled so that the mold opening and locking hydraulic cylinder returns oil to the oil tank through the pre-mold opening oil return circuit, thereby effectively releasing the deformation energy of the mold plate after high-pressure mold locking in advance, avoiding vibration of the mold during the mold opening process, ensuring the accuracy of the mold opening position and shortening the mold opening time cycle, thereby improving production efficiency. In addition, the pre-mold opening oil return circuit of the present invention allows the mold opening and locking hydraulic cylinder to return oil directly to the oil tank, the oil circuit design is simple and reasonable, and the later operation and maintenance are more convenient, and there is no need to use a proportional directional valve with high configuration and cost, which greatly reduces equipment cost and labor cost.

[0025] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 A mold opening and locking hydraulic control system according to a specific embodiment of the present invention is demonstrated.

[0028] Description of Reference Numerals

[0029] 1 Open and lock mold hydraulic cylinder 11 rodless cavity

[0030] 12 rod chamber 13 piston rod

[0031] 2First working oil circuit 3Second working oil circuit

[0032] 4 Main oil inlet circuit 5 Main oil return circuit

[0033] 6 Pre-opening mold return oil circuit 7 Pre-opening mold replenishing oil circuit

[0034] 8 First pilot control oil circuit 9 Damping valve

[0035] 10 The second pilot control oil circuit V1 opens the mold locking main valve

[0036] V2 Switch valve V3 First cartridge valve

[0037] V4 pilot proportional relief valve V5 second cartridge valve

[0038] V6 pilot control directional valve V7 pre-opening mold oil supply valve

[0039] V8 check valve P main valve oil inlet

[0040] T Main valve oil return port A First working oil port

[0041] B Second working oil port DETAILED DESCRIPTION

[0042] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0043] The following describes the mold opening and locking hydraulic control system according to the present invention with reference to the accompanying drawings. The mold opening and locking hydraulic control system has low cost and can achieve the functions of effectively and quickly releasing the template deformation in advance and actively, quickly and smoothly braking during the mold opening process.

[0044] like Figure 1As shown, the mold opening and locking hydraulic control system of the present invention comprises: a mold opening and locking hydraulic cylinder 1, a mold opening and locking main valve V1 and a pre-opening mold return oil circuit 6. The mold opening and locking hydraulic cylinder 1 is used to control the mold opening and locking actions of the mold. A first working oil circuit 2 and a second working oil circuit 3 are connected between the mold opening and locking main valve V1 and the mold opening and locking hydraulic cylinder 1. The mold opening and locking main valve V1 can be selectively controlled to be in a neutral position, a first reversing position or a second reversing position. When the mold opening and locking main valve V1 is in a neutral position, the first working oil circuit 2 and the second working oil circuit 3 are blocked with the main oil inlet oil circuit 4 or the main oil return oil circuit 5 respectively; when the mold opening and locking main valve V1 is in a first reversing position, the first working oil circuit 2 and the second working oil circuit 3 are connected with the main oil inlet oil circuit 4 and the main oil return oil circuit 5 respectively; when the mold opening and locking main valve V1 is in a second reversing position, the first working oil circuit 2 and the second working oil circuit 3 are connected with the main oil return oil circuit 5 and the main oil inlet oil circuit 4 respectively. The pre-mold return oil circuit 6 is provided with a pre-mold return oil control valve and connected to the first working oil circuit 2, so that it can be controlled by the pre-mold return oil control valve to allow the mold opening and locking hydraulic cylinder 1 to return oil to the oil tank through the pre-mold return oil circuit 6 when the mold opening and locking main valve V1 is in the middle position.

[0045] It should be noted that if Figure 1 As shown, the actuator of the mold opening and locking hydraulic control system of the present invention is the mold opening and locking hydraulic cylinder 1, which is a double-acting single-rod hydraulic cylinder including a rod chamber 12 and a rodless chamber 11. Of course, the present invention is not limited thereto. The mold opening and locking hydraulic cylinder 1 of the present invention may also be, for example, a double-acting double-rod hydraulic cylinder. Figure 1 As shown, the mold opening and locking hydraulic cylinder 1 is a double-acting single-rod hydraulic cylinder. If the mold opening action can be realized when the piston rod 13 of the mold opening and locking hydraulic cylinder 1 moves toward the rodless cavity 11, the rodless cavity 11 of the mold opening and locking hydraulic cylinder 1 of the present invention and the pre-mold opening oil return circuit 6 can be connected to the first working oil circuit 2. At this time, when the mold opening and locking hydraulic control system is in the pre-mold opening step, the deformation of the mold plate and the machine hinge after high-pressure mold locking can be effectively released by pushing the piston rod 13 of the mold opening and locking hydraulic cylinder 1 to move toward the rodless cavity 11, thereby avoiding vibration of the mold during the mold opening process.

[0046] Of course, those skilled in the art can understand that the mold opening and locking hydraulic cylinder 1 is a double-acting single-rod hydraulic cylinder. If the mold opening action can be achieved when the piston rod 13 of the mold opening and locking hydraulic cylinder 1 moves toward the rod chamber 12, then the rod chamber 12 and the pre-mold opening return oil circuit 6 of the mold opening and locking hydraulic cylinder 1 of the present invention can be connected to the first working oil circuit 2. When the mold opening and locking hydraulic control system is in the pre-mold opening step, the deformation of the mold plate and the machine hinge after high-pressure mold locking can be effectively released by pushing the piston rod 13 of the mold opening and locking hydraulic cylinder 1 to move toward the rod chamber 12, thereby avoiding vibration of the mold during the mold opening process.

[0047] The mold opening and locking hydraulic control system of the present invention is provided with a pre-mold opening oil return circuit 6 including a pre-mold opening oil return control valve. When the mold opening and locking hydraulic control system is in the pre-mold opening step, the pre-mold opening oil return control valve is controlled so that the mold opening and locking hydraulic cylinder 1 returns oil to the oil tank through the pre-mold opening oil return circuit 6, thereby effectively releasing the deformation energy of the mold plate after high-pressure mold locking, avoiding vibration of the mold during the mold opening process, ensuring the accuracy of the mold opening position and shortening the mold opening time cycle, thereby improving production efficiency. In addition, the pre-mold opening oil return circuit 6 of the present invention can make the mold opening and locking hydraulic cylinder 1 return oil directly to the oil tank, the oil circuit design is simple and reasonable, and the later operation and maintenance are more convenient, and there is no need to use a proportional directional valve with high configuration and cost, which greatly reduces equipment cost and labor cost.

[0048] Furthermore, the mold opening and locking hydraulic control system includes a pre-mold opening oil replenishment circuit 7 connected to the second working oil circuit 3, and a pre-mold opening oil replenishment valve V7 is provided on the pre-mold opening oil replenishment circuit 7, and is configured to replenish oil to another oil chamber of the mold opening and locking hydraulic cylinder 1 through the pre-mold opening oil replenishment circuit 7 while returning oil from one oil chamber of the mold opening and locking hydraulic cylinder 1 to the oil tank through the pre-mold opening oil return circuit 6. During this process, the system does not need to provide power. Figure 1 As shown, the rodless chamber 11 is connected to the first working oil circuit 2, and the rod chamber 12 is connected to the second working oil circuit 3. When the template is in the pre-opening mold state, the rodless chamber 11 returns oil to the oil tank through the pre-opening mold return oil circuit 6, and the pre-opening mold replenishing oil circuit 7 replenishes oil to the rod chamber 12 so that the piston rod can retract.

[0049] Similarly, those skilled in the art can understand that if the rodless chamber 11 is connected to the second working oil circuit 3 and the rod chamber 12 is connected to the first working oil circuit 2, when the rod chamber 12 returns oil to the oil tank through the pre-opening mold return oil circuit 6, the pre-opening mold oil replenishing oil circuit 7 replenishes oil to the rodless chamber 11.

[0050] Optionally, the pre-mold oil supply circuit 7 may be, for example, a tubular one-way valve.

[0051] The mold opening and locking hydraulic control system of the present invention can realize the mold opening action when the piston rod 13 of the mold opening and locking hydraulic cylinder 1 moves toward the rodless chamber 11, and can also realize the mold opening action when the piston rod 13 of the mold opening and locking hydraulic cylinder 1 moves toward the rod chamber 12. However, in order to explain the mold opening and locking hydraulic control system of the present invention more briefly and clearly, in the following specific embodiments, the mold opening action is realized when the piston rod 13 of the mold opening and locking hydraulic cylinder 1 moves toward the rodless chamber 11, the rodless chamber 11 is connected to the first working oil circuit 2, and the rod chamber 12 is connected to the second working oil circuit 3.

[0052] Optionally, when the mold opening and locking hydraulic cylinder 1 includes a rodless chamber 11 and a rod chamber 12, the mold opening and locking main valve V1 includes a main valve oil inlet P connected to the main oil inlet circuit 4, a main valve oil return port T connected to the main oil return circuit 5, a first working oil port A connected to the rodless chamber 11 through the first working oil circuit 2, and a second working oil port B connected to the rod chamber 12 through the second working oil circuit 3, wherein when the mold opening and locking main valve V1 is in the middle position, the main valve oil inlet P, the main valve oil return port T, and the first working oil port A and the second working oil port B are all blocked; when the mold opening and locking main valve V1 is in the first switching position, the main valve oil inlet P is connected to the first working oil port A, and the second working oil port B is connected to the main valve oil return port T; when the mold opening and locking main valve V1 is in the second switching position, the main valve oil inlet P is connected to the second working oil port B, and the first working oil port A is connected to the main valve oil return port T. Figure 1 As shown, when both YA1 and YA2 of the mold opening and locking main valve V1 are not energized, the mold opening and locking main valve V1 is in the middle position, and the template can be in the mold locking pressure holding state or the mold pre-opening state; when YA1 of the mold opening and locking main valve V1 is energized, the mold opening and locking main valve V1 is in the first switching position, and the template can be in the mold locking state; when YA2 of the mold opening and locking main valve V1 is energized, the mold opening and locking main valve V1 is in the second switching position, and the template can be in the mold opening state.

[0053] Optionally, the mold opening and locking main valve V1 may be, for example, a three-position four-way electro-hydraulic directional valve.

[0054] Furthermore, the pre-mold opening oil return control valve includes a switch valve V2 for controlling the on-off of the pre-mold opening oil return oil circuit 6. The switch valve V2 has a fast response speed based on its own switch characteristics, and can quickly release the deformation of the template after high-pressure mold locking, thereby avoiding vibration of the mold during the mold opening process. The switch valve V2 can be, for example, a two-position two-way electromagnetic directional valve. When the template is in the pre-mold opening or mold opening high-speed state, the switch valve V2 is placed in a connected state by controlling YA4 of the switch valve V2. At this time, the rodless cavity 11 returns oil to the oil tank through the switch valve V2; when the template is in the mold locking state, the switch valve V2 is placed in a blocked state by controlling YA4 of the switch valve V2.

[0055] Furthermore, in order to realize pre-mold opening, stable and fast mold opening and braking, the pre-mold opening oil return control valve also includes a first cartridge valve V3 connected in parallel with the switch valve V2, and the control oil port of the first cartridge valve V3 is connected to the first pilot control oil circuit 8, and the first pilot control oil circuit 8 is provided with a pilot proportional relief valve V4 for controlling the on and off of the first cartridge valve V3. Specifically, Figure 1As shown, the oil inlet and control oil port of the first cartridge valve V3 are connected to the first working oil circuit 2, and the oil outlet of the first cartridge valve V3 is connected to the oil outlet of the switch valve V2 or the oil tank; the oil inlet of the pilot proportional relief valve V4 is connected to the control oil port of the first cartridge valve V3, and the oil outlet of the pilot proportional relief valve V4 is connected to the oil outlet of the first cartridge valve V3 or the oil tank. When the template is in the pre-mold opening state, the rodless chamber 11 can return oil to the oil tank through the pre-mold opening oil return control valve; when the template is in the mold opening state, the rodless chamber 11 can not only return oil to the oil tank through the pre-mold opening oil return control valve, but also can make the mold opening action high-speed by increasing the system pressure flow command and controlling YA5 of the pilot proportional relief valve V4. After the high-speed mold opening section, the rodless chamber 11 has a mold opening back pressure of 10~30bar through the control of YA5 of the pilot proportional relief valve V4, thereby achieving active and rapid braking action. That is, in some embodiments, by controlling the pre-mold opening oil return control valve during the mold opening process, the pressure of the rodless chamber 11 can be adjusted from 0 to 245 bar, and the high-speed mold opening section can achieve 0 back pressure, thereby being more energy-efficient and making the low speed at the end of the mold opening more stable.

[0056] Optionally, a damping valve 9 is provided on the pre-mold return oil circuit 6, and the damping valve 9 can appropriately adjust the size of the damping hole according to the actual working conditions, thereby ensuring the stable operation of the switch valve V2 and the first cartridge valve V3. Figure 1 As shown, one end of the damping valve 9 is connected to the first working oil circuit 2, and the other end of the damping valve 9 is connected to the oil inlet of the first cartridge valve V3 and the oil inlet of the switch valve V2.

[0057] In some embodiments, the mold opening and locking hydraulic control system further includes an express valve group unit disposed on the main oil return line 5, the express valve group unit includes a second cartridge valve V5, the control oil line of the second cartridge valve V5 is connected to a second pilot control oil line 10, and the second pilot control oil line 10 is provided with a pilot control directional valve V6 for controlling the on and off of the second cartridge valve V5. Specifically, Figure 1 As shown, the oil inlet and control oil port of the second cartridge valve V5 are connected to the main valve oil return port T, and the oil outlet of the second cartridge valve V5 is connected to the oil tank; the oil inlet and oil outlet of the pilot control directional valve V6 are connected to the control oil port and the oil tank of the second cartridge valve V5 respectively. The pilot control directional valve V6 can be, for example, a two-position four-way electromagnetic directional valve. When the mold plate is in the mold locking state, YA1 of the mold unlocking main valve V1 is energized, and YA3 of the pilot control directional valve V6 is not energized, the second pilot control oil circuit 10 is connected, and the rod chamber 12 returns oil to the oil tank through the second cartridge valve V5.

[0058] Furthermore, in order to realize the mold locking differential, a one-way valve V8 with a positive oil port facing the main oil return oil circuit 5 is connected between the main oil inlet oil circuit 4 and the main oil return oil circuit 5. The one-way valve V8 can only return oil from the main oil return oil circuit 5 to the main oil inlet oil circuit 4, and the one-way valve V8 is in a blocked state when it is reversed from the main oil inlet oil circuit 4 to the main oil return oil circuit 5. When the mold is in the mold locking differential state, YA1 of the mold unlocking and locking main valve V1 is energized, YA3 of the pilot control directional valve V6 is energized, the second cartridge valve V5 is blocked, and the rod chamber 12 returns oil to the rodless chamber 11 through the one-way valve V8 and the mold unlocking and locking main valve V1. Among them, the one-way valve V8 can be, for example, a plate-type one-way valve.

[0059] Correspondingly, the present invention also provides a compression molding device, which includes the above-mentioned mold opening and locking hydraulic control system. Specifically, the compression molding device can be, for example, an injection molding device (injection molding machine) or a die-casting machine.

[0060] In addition, the present invention also provides a mold control method for a compression molding device, including a mold locking step, a pre-mold opening step and a mold opening step. In the pre-mold opening step, the mold opening and locking main valve V1 for controlling the mold opening and locking action is in a neutral position, and the mold opening and locking hydraulic cylinder 1 returns oil to the oil tank through the pre-mold opening oil return oil circuit 6. The pre-mold opening oil return oil circuit 6 allows the mold opening and locking hydraulic cylinder 1 to return oil directly to the oil tank, and the oil circuit design is simple and reasonable, and the subsequent operation and maintenance are also more convenient.

[0061] Further, the pre-mold opening oil return control valve arranged on the pre-mold opening oil return oil circuit 6 includes a first cartridge valve V3, the control oil port of the first cartridge valve V3 is connected to a first pilot control oil circuit, and the first pilot control oil circuit is provided with a pilot proportional relief valve V4 for controlling the on-off of the first cartridge valve V3. The mold opening step includes:

[0062] S1. High-speed mold opening step, in which the mold opening and locking hydraulic cylinder 1 returns oil to the oil tank through the first cartridge valve V3 in the pre-mold opening oil return oil circuit 6. By controlling the pre-mold opening oil return control valve during the mold opening process, the pressure of the rodless chamber 11 can be adjusted from 0 to 245 bar, and zero back pressure rapid mold opening can be achieved in the high-speed mold opening section.

[0063] Furthermore, the mold opening steps include:

[0064] S1. Mold opening brake sub-step, in which the mold opening and locking hydraulic cylinder 1 throttles the oil back to the oil tank through the pre-mold opening oil return oil circuit 6. By throttling the return oil of the mold opening and locking hydraulic cylinder 1, the mold opening and locking hydraulic cylinder 1 has an appropriate mold opening back pressure, thereby achieving active and rapid braking action.

[0065] The mold opening and locking hydraulic control system, compression molding equipment and mold control method of the compression molding equipment of the present invention are simple and reasonable in design, and the subsequent operation and maintenance are also more convenient. Only through the optimization and coordination of several common valves, the expensive and high-quality proportional valves can be replaced, so that the configuration of the mold opening and locking directional valve can also achieve the pre-opening and smooth and fast mold opening functions when the configuration is reduced by one level, which greatly reduces the equipment cost and labor cost, and effectively avoids the problem of cavitation of the cylinder pipeline caused by improper setting of the proportional valve opening. In addition, the mold opening and locking hydraulic control system of the present invention can greatly optimize the vibration, position accuracy and time cycle of the mold opening by controlling the time state of each valve, thereby improving the machine operation efficiency; the control program is simple, the human-machine exchangeability is good, and the professional level requirements for the operator are low, which not only meets the requirements of the production process, but also reduces the wear between the mechanical structures, and greatly extends the service life of the machine.

[0066] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0067] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0069] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A hydraulic control system for opening and locking molds, characterized in that: The hydraulic control system for opening and locking molds comprises: A mold opening and locking hydraulic cylinder (1), wherein the mold opening and locking hydraulic cylinder (1) is used to control the mold opening and locking actions of the mold; A mold opening and locking main valve (V1), wherein a first working oil circuit (2) and a second working oil circuit (3) are connected between the mold opening and locking main valve (V1) and the mold opening and locking hydraulic cylinder (1); the mold opening and locking main valve (V1) can be selectively controlled to be in a neutral position, a first switching position or a second switching position; when the mold opening and locking main valve (V1) is in the neutral position, the first working oil circuit (2) and the second working oil circuit (3) are respectively blocked from the main oil inlet circuit (4) or the main oil return circuit (5); when the mold opening and locking main valve (V1) is in the first switching position, the first working oil circuit (2) and the second working oil circuit (3) are respectively connected to the main oil inlet circuit (4) and the main oil return circuit (5); when the mold opening and locking main valve (V1) is in the second switching position, the first working oil circuit (2) and the second working oil circuit (3) are respectively connected to the main oil return circuit (5) and the main oil inlet circuit (4); a pre-mold opening oil return circuit (6), wherein the pre-mold opening oil return circuit (6) is provided with a pre-mold opening oil return control valve and is connected to the first working oil circuit (2), so that the pre-mold opening oil return control valve can be controlled to allow the mold opening and locking hydraulic cylinder (1) to return oil to the oil tank through the pre-mold opening and locking oil return circuit (6) when the mold opening and locking main valve (V1) is in the middle position, the pre-mold opening oil return control valve comprises a switch valve (V2) for controlling the on and off of the pre-mold opening oil return circuit (6) and a first cartridge valve (V3) connected in parallel with the switch valve (V2), the control oil port of the first cartridge valve (V3) is connected to a first pilot control circuit (8), and the first pilot control circuit (8) is provided with a pilot proportional relief valve (V4) for controlling the on and off of the first cartridge valve (V3); and, A pre-mold opening oil replenishment circuit (7) connected to the second working oil circuit (3) is provided with a pre-mold opening oil replenishment valve (V7) and is configured to replenish oil to another oil chamber of the mold opening and locking hydraulic cylinder (1) through the pre-mold opening oil replenishment circuit (7) while returning oil from one oil chamber of the mold opening and locking hydraulic cylinder (1) through the pre-mold opening oil return circuit (6).

2. The mold opening and locking hydraulic control system according to claim 1, characterized in that: The mold opening and locking hydraulic cylinder (1) comprises a rodless chamber (11) and a rod chamber (12); the mold opening and locking main valve (V1) comprises a main valve oil inlet (P) connected to the main oil inlet circuit (4), a main valve oil return port (T) connected to the main oil return circuit (5), a first working oil port (A) connected to the rodless chamber (11) via the first working oil circuit (2), and a second working oil port (B) connected to the rod chamber (12) via the second working oil circuit (3), wherein: When the mold opening and locking main valve (V1) is in the middle position, the main valve oil inlet (P), the main valve oil return port (T) and the first working oil port (A) and the second working oil port (B) are all blocked; When the mold opening and locking main valve (V1) is in the first switching position, the main valve oil inlet (P) is connected to the first working oil port (A), and the second working oil port (B) is connected to the main valve oil return port (T); When the mold opening and locking main valve (V1) is in the second switching position, the main valve oil inlet (P) is connected to the second working oil port (B), and the first working oil port (A) is connected to the main valve oil return port (T).

3. The mold opening and locking hydraulic control system according to claim 1, characterized in that: A damping valve (9) is provided on the pre-mold oil return line (6).

4. The mold opening and locking hydraulic control system according to claim 1, characterized in that: The mold opening and locking hydraulic control system further comprises an express valve group unit arranged on the main oil return circuit (5), the express valve group unit comprising a second cartridge valve (V5), the control circuit of the second cartridge valve (V5) being connected to a second pilot control circuit (10), the second pilot control circuit (10) being provided with a pilot control directional valve (V6) for controlling the on and off of the second cartridge valve (V5).

5. The mold opening and locking hydraulic control system according to claim 1, characterized in that: A one-way valve (V8) with a forward oil port facing the main oil return circuit (5) is connected between the main oil inlet circuit (4) and the main oil return circuit (5).

6. A compression molding device, characterized in that: The compression molding equipment comprises a mold opening and locking hydraulic control system according to any one of claims 1 to 5.

7. A mold control method for a compression molding device, comprising a mold locking step, a pre-mold opening step and a mold opening step, characterized in that: In the pre-mold opening step, the mold opening and locking main valve (V1) for controlling the mold opening and locking action is in a neutral position, and the mold opening and locking hydraulic cylinder (1) returns oil to the oil tank through the pre-mold opening oil return line (6).

8. The mold control method of the compression molding equipment according to claim 7, characterized in that: The pre-mold opening oil return control valve on the pre-mold opening oil return oil circuit (6) comprises a first cartridge valve (V3), a control oil port of the first cartridge valve (V3) is connected to a first pilot control oil circuit, and a pilot proportional relief valve (V4) for controlling the on and off of the first cartridge valve (V3) is provided on the first pilot control oil circuit. The mold opening step comprises: S1. A high-speed mold opening step, in which the mold opening and locking hydraulic cylinder (1) returns oil to the oil tank through the first cartridge valve (V3) in the pre-mold opening oil return circuit (6).

9. The mold control method of compression molding equipment according to claim 8, characterized in that: The mold opening step comprises: S2. A mold opening and braking sub-step, in which the mold opening and locking hydraulic cylinder (1) throttles the oil back to the oil tank through the pre-mold opening oil return line (6).

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