Hydraulic system of injection molding machine

Abstract

The utility model provides a hydraulic system of an injection molding machine, which consists of a sol pumping and shooting hydraulic unit, a seat moving hydraulic unit, a mold opening and closing hydraulic unit, a mold adjusting hydraulic unit, an ejector pin hydraulic unit, a core pulling hydraulic unit and the like, and is provided with a first hydraulic driving unit and a second hydraulic driving unit for driving respectively. By means of the design, the mold closing action and the glue injection action are synchronously carried out, it is guaranteed that the pressure of an inner cavity of the mold is small in the initial glue injection stage, and therefore the injection amount of glue injection and the quality of finished products are guaranteed. In addition, according to the system, oil supply and oil return paths are optimized through modular design, the performance and stability of the system are improved, meanwhile, maintenance and debugging are convenient, and the operation cost is reduced. The hydraulic system provides powerful guarantee for efficient and stable operation of the injection molding machine.

Description

Technical Field

[0001] The utility model relates to the technical field of plastic processing, in particular to a hydraulic system for an injection molding machine. Background Art

[0002] Injection molding machine is a common plastic processing equipment, which has the advantages of high production efficiency and easy automation. However, the existing injection molding machine has the following disadvantages when processing plastic parts:

[0003] (1) Due to fast injection rate, low injection pressure or unreasonable mold structure, the surface crystallinity of the finished product may be inconsistent, forming flow lines on the surface of the finished product.

[0004] (2) Due to the poor fluidity of the melt injected into the mold, a clear bonding line is formed on the surface of the finished product, affecting the quality of the finished product.

[0005] The above disadvantages are particularly prominent when injection molding optical components, and existing injection molding machines have no way to overcome the above disadvantages.

[0006] In addition, during the injection and feeding process of the traditional injection molding machine, since the hydraulic system only has one set of hydraulic drive units, the mold closing and injection actions are performed separately and cannot be performed synchronously. At the same time, the existing hydraulic system also has certain deficiencies in the design of the oil supply and return lines, which affects the performance of the injection molding machine.

[0007] The utility model with application number 201710550532.6 provides a hydraulic system for an injection molding machine, including: a proportional valve, a liquid storage tank, a driving pump, an accumulator, a relief valve, a cooling device, an execution circuit and liquid metal. The utility model adopts liquid metal instead of traditional hydraulic oil as the transmission medium of the hydraulic system. The liquid metal enters the driving pump from the liquid storage tank, and the driving force of the driving pump causes the liquid metal to flow to the proportional valve. The liquid metal flows to the first end of the execution circuit through the flow and pressure regulation of the proportional valve; at the same time, the liquid metal flows from the driving pump to the relief valve, and then flows to the liquid storage tank through the pressure regulation of the relief valve; the liquid metal flows to the cooling device through the second end of the execution circuit, and the liquid metal dissipates heat through the cooling device and then flows to the liquid storage tank; the liquid metal flows from the first end of the execution circuit to the accumulator for energy storage. The hydraulic system of the injection molding machine provided by the utility model has high energy-saving efficiency, good system stability and high production efficiency.

[0008] However, the above patented technology cannot overcome the problems existing in the prior art. At present, there is an urgent need for an injection feeding process of an injection molding machine that can overcome the problems existing in the prior art. Utility Model Content

[0009] The purpose of the utility model is to provide a hydraulic system for an injection molding machine dedicated to the injection feeding process of the injection molding machine to solve the problems raised in the above background technology:

[0010] (1) How to realize the independent driving of the ejection hydraulic unit and the seat shifting hydraulic unit in the original hydraulic system, and how to realize the independent driving of the mold opening and closing hydraulic unit, the mold adjustment hydraulic unit, the ejector hydraulic unit and the core pulling hydraulic unit in the original hydraulic system.

[0011] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0012] A hydraulic system of an injection molding machine, comprising a melt injection hydraulic unit, a seat shifting hydraulic unit, a mold opening and closing hydraulic unit, a mold adjustment hydraulic unit, an ejector hydraulic unit and a core pulling hydraulic unit;

[0013] Also included is a first hydraulic drive unit and a second hydraulic drive unit;

[0014] The two ends of the first hydraulic drive unit are respectively a liquid inlet end and a liquid outlet end, the first hydraulic drive unit is connected to the liquid storage tank through the liquid inlet end, and the first hydraulic drive unit supplies oil to the ejection melt hydraulic unit and the seat movement hydraulic unit respectively through the liquid outlet end;

[0015] The second hydraulic drive unit is also provided with a liquid inlet and a liquid outlet at both ends, and the second hydraulic drive unit is connected to the liquid storage tank through the liquid inlet, and the second hydraulic drive unit supplies oil to the mold opening and closing hydraulic unit, the mold adjustment hydraulic unit, the ejector hydraulic unit and the core pulling hydraulic unit through the liquid outlet.

[0016] The oil return paths of the injection melt hydraulic unit, the seat shifting hydraulic unit, the mold opening and closing hydraulic unit, the mold adjusting hydraulic unit, the ejector hydraulic unit and the core pulling hydraulic unit are communicated with the liquid storage tank.

[0017] On the basis of the above technical solution, the present invention can also be improved as follows.

[0018] Further, the first hydraulic drive unit includes a first drive pump and a first motor, the first motor drives the first drive pump to work, the first drive pump inlet is the liquid inlet end of the first hydraulic drive unit, and the first drive pump outlet is the liquid outlet end of the first hydraulic drive unit;

[0019] The second hydraulic drive unit includes a second drive pump and a second motor. The second motor drives the second drive pump to work. The inlet of the second drive pump is the liquid inlet end of the second hydraulic drive unit, and the outlet of the second drive pump is the liquid outlet end of the second hydraulic drive unit.

[0020] Furthermore, an overflow valve is installed on the fluid circuit of the first hydraulic drive unit; an overflow valve is also installed on the fluid circuit of the second hydraulic drive unit.

[0021] Furthermore, coolers are installed on the oil return lines of the injection melt hydraulic unit, the seat shifting hydraulic unit, the mold opening and closing hydraulic unit, the mold adjusting hydraulic unit, the ejector hydraulic unit and the core pulling hydraulic unit.

[0022] The hydraulic system of the injection molding machine is provided with a first hydraulic drive unit and a second hydraulic drive unit, which can realize synchronous mold closing and glue injection, realize the linkage between the mold closing and glue injection of the injection molding machine, realize that the pressure in the mold cavity of the injection molding machine is relatively small at the initial stage of glue injection, ensure the injection amount of the glue, and prevent flow lines from forming on the surface of the finished product, thereby ensuring the quality of the finished product.

[0023] The beneficial technical effects of the hydraulic system of this injection molding machine are:

[0024] (1) Optimized hydraulic system: By optimizing the design of the hydraulic system, the oil supply and return are smoother, improving the performance and stability of the entire system;

[0025] (2) Easy maintenance and debugging: The modular design of the hydraulic system makes maintenance and debugging more convenient, reducing operating costs;

[0026] (3) Optimized hydraulic system: By optimizing the design of the hydraulic system, the oil supply and return are smoother, improving the performance and stability of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a hydraulic principle diagram of an embodiment of the hydraulic system of the injection molding machine.

[0028] Figure 2 It is a hydraulic principle diagram of the first hydraulic drive unit, the melt injection hydraulic unit and the seat shifting hydraulic unit in the hydraulic system embodiment of the injection molding machine.

[0029] Figure 3 It is a hydraulic principle diagram of the second hydraulic drive unit, the mold opening and closing hydraulic unit, the mold adjustment hydraulic unit, the ejector hydraulic unit and the core pulling hydraulic unit in the hydraulic system embodiment of the injection molding machine.

[0030] Description of the numbers in the figure:

[0031] Injection glue hydraulic unit-1100; injection glue cylinder-1110; melt glue hydraulic motor-1120; seat shifting hydraulic unit-1200; seat shifting cylinder-1210; mold opening and closing hydraulic unit-1300; mold opening and closing cylinder-1310; mold adjustment hydraulic unit-1400; mold adjustment hydraulic motor-1410; ejector hydraulic unit-1500; ejector cylinder-1510; core pulling hydraulic unit-1600; first hydraulic drive unit-2100; first drive pump-2110; first motor-2120; overflow valve-2300; second hydraulic drive unit-2200; second drive pump-2210; second motor-2220; cooler-3100. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation of the utility model is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific implementation disclosed below.

[0033] The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementations.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0035] See also Figures 1 to 3 .

[0036] The hydraulic system of the injection molding machine includes a melt ejection hydraulic unit 1100, a seat shifting hydraulic unit 1200, a mold opening and closing hydraulic unit 1300, a mold adjustment hydraulic unit 1400, an ejector hydraulic unit 1500, a core pulling hydraulic unit 1600, a first hydraulic drive unit 2100 and a second hydraulic drive unit 2200.

[0037] The ejection melt hydraulic unit 1100 is provided with an ejection melt cylinder 1110, a melt hydraulic motor 1120, a reversing valve, a pipeline and other components. The ejection melt hydraulic unit 1100 controls the extension and retraction of the ejection melt cylinder 1110, and at the same time controls the start and stop of the melt hydraulic motor 1120. The seat shift hydraulic unit 1200 is provided with a reversing valve, a pipeline and other components. The seat shift hydraulic unit 1200 controls the extension and retraction of the seat shift cylinder 1210. The mold opening and closing hydraulic unit 1300 is provided with components such as a reversing valve and a pipeline, and the mold opening and closing hydraulic unit 1300 controls the extension and retraction of the mold opening and closing cylinder 1310; the mold adjustment hydraulic unit 1400 is provided with components such as a reversing valve and a pipeline, and the mold adjustment hydraulic unit 1400 controls the start and stop of the mold adjustment hydraulic motor 1410; the ejector hydraulic unit 1500 is provided with components such as a reversing valve and a pipeline, and the ejector hydraulic unit 1500 controls the extension and retraction of the ejector cylinder 1510.

[0038] The two ends of the first hydraulic drive unit 2100 are respectively a liquid inlet end and a liquid outlet end. The first hydraulic drive unit 2100 is connected to the liquid storage tank through the liquid inlet end. The first hydraulic drive unit 2100 includes a first drive pump 2110 and a first motor 2120. The first motor 2120 drives the first drive pump 2110 to work. The inlet of the first drive pump 2110 is the liquid inlet end of the first hydraulic drive unit 2100, and the outlet of the first drive pump 2110 is the liquid outlet end of the first hydraulic drive unit 2100. The first hydraulic drive unit 2100 supplies oil to the injection melt hydraulic unit 1100 and the seat displacement hydraulic unit 1200 respectively through the liquid outlet end. An overflow valve 2300 is installed on the liquid circuit of the first hydraulic drive unit 2100.

[0039] The second hydraulic drive unit 2200 is also provided with a liquid inlet and a liquid outlet at both ends, and the second hydraulic drive unit 2200 is connected to the liquid storage tank through the liquid inlet. The second hydraulic drive unit 2200 includes a second drive pump 2210 and a second motor 2220. The second motor 2220 drives the second drive pump 2210 to work. The inlet of the second drive pump 2210 is the liquid inlet of the second hydraulic drive unit 2200, and the outlet of the second drive pump 2210 is the liquid outlet of the second hydraulic drive unit 2200. The second hydraulic drive unit 2200 supplies oil to the mold opening and closing hydraulic unit 1300, the mold adjustment hydraulic unit 1400, the ejector hydraulic unit 1500 and the core pulling hydraulic unit 1600 through the liquid outlet. An overflow valve 2300 is also installed on the liquid circuit of the second hydraulic drive unit 2200.

[0040] The oil return lines of the melt-jet hydraulic unit 1100, the seat-shifting hydraulic unit 1200, the mold-opening and -closing hydraulic unit 1300, the mold-adjusting hydraulic unit 1400, the ejector hydraulic unit 1500 and the core-pulling hydraulic unit 1600 are connected to the liquid storage tank, and a cooler 3100 is installed on the oil return lines of the melt-jet hydraulic unit 1100, the seat-shifting hydraulic unit 1200, the mold-opening and -closing hydraulic unit 1300, the mold-adjusting hydraulic unit 1400, the ejector hydraulic unit 1500 and the core-pulling hydraulic unit 1600.

[0041] The injection and feeding process of the injection molding machine is completed by using the hydraulic system of the injection molding machine, including the following steps:

[0042] a) The total stroke of the mold during the injection molding process is divided into a first preliminary stroke and a first terminal stroke, the distance of the first preliminary stroke accounts for 80% of the total stroke of the mold, and the distance of the first terminal stroke accounts for 20% of the total stroke of the mold;

[0043] b) Independent mold closing: Control the mold of the injection molding machine to move gradually through the initial stroke at a uniform speed;

[0044] c) The total stroke of the screw during the injection molding process is divided into the second preliminary stroke, linkage stroke and pressure holding stroke. The distance of the second preliminary stroke accounts for 70% of the total stroke of the mold, the distance of the end stroke accounts for 20% of the total stroke of the mold, and the distance of the pressure holding stroke accounts for 10% of the total stroke of the mold;

[0045] d) Mold closing and injection linkage: The mold of the injection molding machine continues to move at a constant speed into the first end stroke, and the mold of the injection molding machine moves to the end of the first end stroke at a constant speed to complete the mold closing action;

[0046] During the first terminal stroke of the injection molding machine mold, the screw of the injection molding machine is controlled to move toward the mold to inject the molten material into the mold cavity formed by the mold. When the mold of the injection molding machine completes the mold closing action, the stroke path of the screw of the injection molding machine is the second preliminary stroke.

[0047] e) Injection and pressure holding linkage: control the screw of the injection molding machine to continue moving toward the mold until the screw of the injection molding machine moves to the end of the pressure holding stroke at a uniform speed;

[0048] When the screw of the injection molding machine moves forward during the holding stroke, the pressure inside the mold of the injection molding machine is consistent with the preset holding pressure;

[0049] f) Independent pressure holding: Continue to hold the pressure of the fleece material in the mold of the injection molding machine until the pressure holding action is completed.

[0050] After the injection and feeding process of the injection molding machine is completed, it is also necessary to perform the forward withdrawal action (which can be omitted), the feeding action, the cooling action and the mold opening action to complete the injection molding machine processing.

[0051] The injection and feeding process of this injection molding machine uses the linkage between mold closing and injection to achieve a low pressure in the mold cavity of the injection molding machine at the initial stage of injection, ensuring the injection amount of injection, and not easily forming flow lines on the surface of the finished product. Then, the injection and pressure holding linkage are used to achieve a stable pressure in the mold cavity of the injection molding machine at the later stage of injection, supplement the insufficient space due to the cooling and shrinkage of the resin, and obtain the best mold replication effect, fully ensure the fluidity of the melt injected into the mold, dilute the bonding line formed on the surface of the finished product, and ensure the quality of the finished product. Especially when the injection molding machine is processing and molding optical components, the lens or other molded finished products have better optical parameters.

[0052] The above is only one embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the principle of the present invention, and these should also be regarded as belonging to the protection scope of the present invention.

Claims

1. A hydraulic system for an injection molding machine, comprising a melt injection hydraulic unit (1100), a seat shifting hydraulic unit (1200), a mold opening and closing hydraulic unit (1300), a mold adjustment hydraulic unit (1400), an ejector hydraulic unit (1500) and a core pulling hydraulic unit (1600); Features: Also includes a first hydraulic drive unit (2100) and a second hydraulic drive unit (2200); The first hydraulic drive unit (2100) has two ends, namely, a liquid inlet end and a liquid outlet end. The first hydraulic drive unit (2100) is connected to the liquid storage tank via the liquid inlet end. The first hydraulic drive unit (2100) supplies oil to the ejection melt hydraulic unit (1100) and the seat displacement hydraulic unit (1200) respectively via the liquid outlet end. The second hydraulic drive unit (2200) is also provided with a liquid inlet end and a liquid outlet end at both ends, and the second hydraulic drive unit (2200) is connected to the liquid storage tank via the liquid inlet end, and the second hydraulic drive unit (2200) supplies oil to the mold opening and closing hydraulic unit (1300), the mold adjustment hydraulic unit (1400), the ejector hydraulic unit (1500) and the core pulling hydraulic unit (1600) respectively via the liquid outlet end; The oil return paths of the injection molten glue hydraulic unit (1100), the seat shifting hydraulic unit (1200), the mold opening and closing hydraulic unit (1300), the mold adjusting hydraulic unit (1400), the ejector hydraulic unit (1500) and the core pulling hydraulic unit (1600) are communicated with the liquid storage tank.

2. The hydraulic system of the injection molding machine according to claim 1, characterized in that: The first hydraulic drive unit (2100) comprises a first drive pump (2110) and a first motor (2120); the first motor (2120) drives the first drive pump (2110) to work; the inlet of the first drive pump (2110) is the liquid inlet end of the first hydraulic drive unit (2100); and the outlet of the first drive pump (2110) is the liquid outlet end of the first hydraulic drive unit (2100); The second hydraulic drive unit (2200) comprises a second drive pump (2210) and a second motor (2220), wherein the second motor (2220) drives the second drive pump (2210) to work, wherein the inlet of the second drive pump (2210) is the liquid inlet end of the second hydraulic drive unit (2200), and the outlet of the second drive pump (2210) is the liquid outlet end of the second hydraulic drive unit (2200).

3. The hydraulic system of the injection molding machine according to claim 2, characterized in that: The fluid circuit of the first hydraulic drive unit (2100) is provided with an overflow valve (2300); the fluid circuit of the second hydraulic drive unit (2200) is also provided with an overflow valve (2300).

4. The hydraulic system of the injection molding machine according to claim 1, characterized in that: A cooler (3100) is installed on the oil return lines of the injection molten glue hydraulic unit (1100), the seat shifting hydraulic unit (1200), the mold opening and closing hydraulic unit (1300), the mold adjustment hydraulic unit (1400), the ejector hydraulic unit (1500) and the core pulling hydraulic unit (1600).

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