Hydraulic system for controlling BMC pressing device of injection molding machine

Abstract

The utility model relates to the technical field of injection molding machines, and particularly discloses a hydraulic system for controlling a BMC (bulk molding compound) material pressing device of an injection molding machine, which comprises an oil tank, a first power unit, a second power unit, a first reversing valve, a second reversing valve and a material pressing oil cylinder, the first power unit or the second power unit can be decided to supply liquid to the material pressing oil cylinder through the first reversing valve, when the material pressing oil cylinder conducts large-flow actions such as ascending or descending, the first power unit with large power can supply liquid to the material pressing oil cylinder, and when the material pressing oil cylinder conducts pressure maintaining small-flow actions, the second power unit can supply liquid to the material pressing oil cylinder. Due to the fact that the power is small, the energy consumption is low, the cost can be saved, when the second power unit conducts pressure maintaining liquid supply, the first power unit can still supply liquid for other actions of the injection molding machine, and the overall efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of injection molding machine, especially a kind of hydraulic system for controlling the BMC material pressing device of injection molding machine. BACKGROUND

[0002] BMC raw material injection molding machine is the special injection molding equipment of molding BMC plastic product, with the continuous improvement of industrial automation level, the requirement of injection molding machine performance is also higher and higher, especially in improving production efficiency, ensuring product quality and guaranteeing operation safety etc.

[0003] The BMC raw material injection molding machine on the market currently controls pressing device, usually on the basis of standard injection molding machine hydraulic power unit, additionally increase a set of larger flow hydraulic power unit to control the action of pressing device, but it has the following problems: first, the cost of large-flow hydraulic power unit is higher, and in the pressure maintaining process of pressing cylinder, the required flow is smaller, and the use of large-flow hydraulic power unit will cause energy waste, and the use of small-flow hydraulic power unit cannot meet the speed requirement of pressing cylinder ascending and descending action. SUMMARY

[0004] The utility model makes out considering the foregoing problem, and the utility model aims at providing a kind of hydraulic system for controlling the BMC material pressing device of injection molding machine, only need to increase a set of small-flow hydraulic power unit, and cooperate with the original power unit of injection molding machine to supply liquid for pressing cylinder, meet the demand of pressing cylinder, and can save cost.

[0005] To achieve the above object, the utility model provides a kind of hydraulic system for controlling the BMC material pressing device of injection molding machine, including oil tank, first power unit, second power unit, first reversing valve, second reversing valve and pressing cylinder, the oil inlet of first power unit and second power unit is communicated with the oil tank;

[0006] First oil inlet, second oil inlet and first oil outlet are equipped on the first reversing valve, the first oil outlet is communicated with the first oil inlet or the second oil inlet, the oil outlet of first power unit is communicated with the first oil inlet, and the oil outlet of second power unit is communicated with the second oil inlet;

[0007] The second reversing valve is provided with a third oil inlet, a first oil return, a first variable oil port and a second variable oil port, when the third oil inlet and the first variable oil port are communicated, the first oil return and the second variable oil port are communicated, when the third oil inlet and the second variable oil port are communicated, the first oil return and the first variable oil port are communicated, the first oil outlet is communicated with the third oil inlet, the first variable oil port is communicated with the rodless chamber of the material pressing oil cylinder, and the second variable oil port is communicated with the rod chamber of the material pressing oil cylinder.

[0008] The power of the second power unit is less than the power of the first power unit.

[0009] According to the hydraulic system for controlling the BMC material pressing device of the injection molding machine, a first one-way valve is arranged between the first variable oil port and the rodless chamber of the material pressing oil cylinder, and the opening of the first one-way valve faces the rodless chamber of the material pressing oil cylinder.

[0010] According to the hydraulic system for controlling the BMC material pressing device of the injection molding machine, a first opening pipeline is further arranged, one end of the first opening pipeline is communicated with the first variable oil port, and the other end of the first opening pipeline is communicated with the second one-way valve, when the first variable oil port discharges oil, the second one-way valve can be opened through the first opening pipeline.

[0011] According to the hydraulic system for controlling the BMC material pressing device of the injection molding machine, a second opening pipeline is further arranged, one end of the second opening pipeline is communicated with the second variable oil port, and the other end of the second opening pipeline is communicated with the first one-way valve, when the second variable oil port discharges oil, the first one-way valve can be opened through the second opening pipeline.

[0012] According to the hydraulic system for controlling the BMC material pressing device of the injection molding machine, a differential valve is further arranged, the differential valve is provided with a third variable oil port, a fourth variable oil port and a second oil return, the fourth variable oil port can be communicated with the third variable oil port or the second oil return, the third variable oil port is communicated with the oil port of the second one-way valve close to the rod chamber of the material pressing oil cylinder, the fourth variable oil port is communicated with the rod chamber of the material pressing oil cylinder, and the second oil return is communicated with the pipeline between the first one-way valve and the rodless chamber of the material pressing oil cylinder.

[0013] The differential valve is provided with a first electromagnet, when the first electromagnet is powered, the fourth variable oil port is communicated with the second oil return port, and when the first electromagnet is powered off, the fourth variable oil port is communicated with the third variable oil port.

[0014] The hydraulic system for controlling the BMC pressure device of the injection molding machine further comprises a first overflow valve, a first pipeline is arranged between the third variable oil port and the oil port of the second one-way valve, and the first overflow valve is communicated with the first pipeline.

[0015] The hydraulic system for controlling the BMC pressure device of the injection molding machine further comprises an electrically-controlled one-way cutoff valve, the electrically-controlled one-way cutoff valve is arranged between the first one-way valve and the rodless cavity of the pressure cylinder, the electrically-controlled one-way cutoff valve can receive an opening and closing signal of a safety door of the injection molding machine, and the electrically-controlled one-way cutoff valve can block the first one-way valve and the rodless cavity of the pressure cylinder.

[0016] The hydraulic system for controlling the BMC pressure device of the injection molding machine further comprises a second overflow valve, a second pipeline is arranged between the first power unit and the first oil inlet, and the second overflow valve is communicated with the second pipeline.

[0017] The hydraulic system for controlling the BMC pressure device of the injection molding machine further comprises a third overflow valve, a third pipeline is arranged between the second power unit and the second oil inlet, and the third overflow valve is communicated with the third pipeline.

[0018] The utility model has the following beneficial effects:

[0019] 1、add second power unit, and can through first reversing valve decides by first power unit or second power unit supplies liquid for pressure cylinder, then can by power greater first power unit supplies liquid for it when pressure cylinder carries out ascending or descending etc. Large flow action, can through second power unit supplies liquid for it when pressure cylinder carries out pressure maintaining small flow work, because its power is smaller, its energy consumption is lower, can save the cost, and when second power unit carries out pressure maintaining supply liquid, first power unit still can supply liquid for injection molding machine other action, improves overall efficiency;

[0020] 2、be equipped with electrically-controlled one-way cutoff valve, pressure cylinder dangerous coefficient is higher and presses down the action, only when the safety door is closed in place, pressure cylinder can start action, improves safety performance;

[0021] 3、when first power unit or second power unit supplies oil for the rodless cavity of pressure cylinder, the hydraulic oil in its rod cavity can be supplemented for the rodless cavity through the differential valve, then differential ascending can be realized, and efficiency is improved;

[0022] 4、In the first variable oil port and the pressure material oil cylinder's rodless cavity between the first check valve, between the second variable oil port and the pressure material oil cylinder's rod cavity is equipped with the second check valve, can pass through the first check valve and the second check valve maintain the oil pressure in the oil inlet chamber;

[0023] 5、In the first pipeline side between the third variable oil port and the second check valve is equipped with the first overflow valve, it can prevent the back oil not smooth due to the blockage, avoid the occurrence of safety accidents. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is the overall oil circuit schematic diagram of embodiment.

[0025] In the figure:

[0026] 1, oil tank;2, first power unit;3, second power unit;4, first reversing valve;5, second reversing valve;6, pressure material oil cylinder;7, first check valve;8, second check valve;9, first opening pipeline;10, second opening pipeline;11, differential valve;12, first overflow valve;13, electric control one-way cut-off valve;14, second overflow valve;15, third overflow valve;16, guard door. DETAILED DESCRIPTION

[0027] The following is the specific embodiment of the utility model and combining the drawings, the technical scheme of the utility model is further described, but the utility model is not limited to these embodiments.

[0028] As Figure 1 Indicated, a kind of hydraulic system for controlling injection molding machine BMC pressure material device, including oil tank 1, first power unit 2, second power unit 3, first reversing valve 4, second reversing valve 5 and pressure material oil cylinder 6.

[0029] Wherein, the oil inlet of first power unit 2 and second power unit 3 are communicated with oil tank 1, and an oil pipe is inserted in the oil inlet, so that liquid can be pumped in oil tank 1 through the oil pipe, and a filter can be arranged at one end of the oil pipe to prevent impurities from entering the power unit.

[0030] Specifically, the first reversing valve 4 is provided with a first oil inlet, a second oil inlet and a first oil outlet, the first oil outlet is in communication with the first oil inlet or the second oil inlet, the oil outlet of the first power unit 2 is in communication with the first oil inlet, the oil outlet of the second power unit 3 is in communication with the second oil inlet, and a second electromagnet is further provided on the first reversing valve 4. During the ascending or descending process of the piston rod of the pressure cylinder 6, the second electromagnet loses power, the first oil inlet is in communication with the first oil outlet, the pressure cylinder 6 is supplied with oil by the first power unit 2, when the pressure cylinder 6 is in the pressure maintaining state, the second electromagnet is powered, the second oil inlet is in communication with the second oil outlet, the pressure cylinder 6 is supplied with oil by the second power unit 3, so that the switching use of the first power unit 2 and the second power unit 3 in different states can be realized. Since the power of the second power unit 3 is less than that of the first power unit 2, the use of the second power unit 3 in the pressure maintaining stage can reduce energy consumption and save cost, and when the second power unit 3 is used for supplying liquid, the first power unit 2 can provide hydraulic oil for the movement of other parts of the injection molding machine, thereby improving the overall efficiency.

[0031] Specifically, the second reversing valve 5 is provided with a third oil inlet, a first oil return port, a first variable oil port and a second variable oil port. When the third oil inlet is in communication with the first variable oil port, the first oil return port is in communication with the second variable oil port. When the third oil inlet is in communication with the second variable oil port, the first oil return port is in communication with the first variable oil port. The first oil outlet is in communication with the third oil inlet. The first variable oil port is in communication with the rodless cavity of the pressure cylinder 6. The second variable oil port is in communication with the rod cavity of the pressure cylinder 6. In this embodiment, the first reversing valve 4 is essentially a two-position four-way valve, and the second reversing valve 5 is essentially a three-position four-way valve. A third electromagnet and a fourth electromagnet are further provided on the second reversing valve 5. When the third electromagnet is powered, the third oil inlet is in communication with the second variable oil port, which supplies oil to the rod cavity of the pressure cylinder 6 through the second variable oil port, and the piston rod of the pressure cylinder 6 descends. The hydraulic oil in the rodless cavity of the pressure cylinder 6 returns to the oil tank 1 through the first variable oil port and the first oil return port. When the fourth electromagnet is powered, the third oil inlet is in communication with the first variable oil port, which supplies oil to the rodless cavity of the pressure cylinder 6 through the first variable oil port, and the piston rod of the pressure cylinder 6 rises. The hydraulic oil in the rod cavity of the pressure cylinder 6 returns through the second variable oil port and the first oil return port. When the third electromagnet and the fourth electromagnet lose power, they are in the middle position, and the piston rod of the pressure cylinder 6 remains stationary.

[0032] In this embodiment, the pressure cylinder 6 is at least one, and can be multiple, without limitation.

[0033] In order to maintain the pressure when the rodless cavity and the rod cavity of the pressure oil cylinder 6 are filled with oil, a first one-way valve 7 is arranged between the first variable oil port and the rodless cavity of the pressure oil cylinder 6, the opening of the first one-way valve 7 faces the rodless cavity of the pressure oil cylinder 6, so that when the rodless cavity is filled with oil through the first variable oil port, the hydraulic oil can only flow towards the rodless cavity of the pressure oil cylinder 6 and cannot flow in the opposite direction, thereby ensuring the stability of the oil pressure in the rodless cavity of the pressure oil cylinder 6, and a second one-way valve 8 is arranged between the second variable oil port and the rod cavity of the pressure oil cylinder 6, the opening of the second one-way valve 8 faces the rod cavity of the pressure oil cylinder 6, and when the rod cavity of the pressure oil cylinder 6 is filled with oil through the second variable oil port, the hydraulic oil can only flow towards the rod cavity of the pressure oil cylinder 6 and cannot flow from the rod cavity of the pressure oil cylinder 6 to the second variable oil port, thereby ensuring the stability of the oil pressure in the rod cavity of the pressure oil cylinder 6.

[0034] In order to avoid the second one-way valve 8 hindering the return of oil in the rod cavity of the pressure oil cylinder 6, a first opening pipeline 9 is further included, one end of the first opening pipeline 9 communicates with the first variable oil port, and the other end of the first opening pipeline 9 communicates with the second one-way valve 8, when the first variable oil port discharges oil, the second one-way valve 8 can be opened through the first opening pipeline 9, and when the rodless cavity of the pressure oil cylinder 6 is filled with oil through the first variable oil port, part of the hydraulic oil will flow into the first opening pipeline 9, the second one-way valve 8 is opened by the hydraulic oil, so that the hydraulic oil in the rod cavity of the pressure oil cylinder 6 can return through the second one-way valve 8.

[0035] In order to avoid the first one-way valve 7 hindering the return of oil in the rodless cavity of the pressure oil cylinder 6, a second opening pipeline 10 is further included, one end of the second opening pipeline 10 communicates with the second variable oil port, and the other end of the second opening pipeline 10 communicates with the first one-way valve 7, when the second variable oil port discharges oil, the first one-way valve 7 can be opened through the second opening pipeline 10, and when the rod cavity of the pressure oil cylinder 6 is filled with oil through the second variable oil port, part of the hydraulic oil will flow into the second opening pipeline 10, the first one-way valve 7 is opened by the hydraulic oil, so that the hydraulic oil in the rodless cavity of the pressure oil cylinder 6 can return through the first one-way valve 7.

[0036] In order to improve the oil efficiency of the rodless cavity of the pressing oil cylinder 6, and further improve the pressing efficiency, a differential valve 11 is further included, the differential valve 11 is provided with a third variable oil port, a fourth variable oil port and a second oil return port, the fourth variable oil port is in communication with the third variable oil port or the second oil return port, the third variable oil port is in communication with the oil port of the second one-way valve 8 close to the rod cavity of the pressing oil cylinder 6, the fourth variable oil port is in communication with the rod cavity of the pressing oil cylinder 6, the second oil return port is in communication with the pipeline between the first one-way valve 7 and the rodless cavity of the pressing oil cylinder 6, specifically, a first electromagnet is arranged on the differential valve 11, when the first electromagnet is powered, the fourth variable oil port is in communication with the second oil return port, when the first electromagnet is de-energized, the fourth variable oil port is in communication with the third variable oil port, then when the rodless cavity of the pressing oil cylinder 6 is supplied with oil through the first one-way valve 7, the first electromagnet is powered, the hydraulic oil in the rod cavity of the pressing oil cylinder 6 flows into the rodless cavity of the pressing oil cylinder 6 through the fourth variable oil port and the second oil return port, realizing differential oil return and accelerating the action efficiency of the pressing oil cylinder 6.

[0037] In order to limit the maximum pressure value in the pressing process of the pressing oil cylinder 6, a first overflow valve 12 is further included, a first pipeline is arranged between the third variable oil port and the oil port of the second one-way valve 8, the first overflow valve 12 is in communication with the first pipeline, then when the pressing oil cylinder 6 is pressed, the rod cavity of the pressing oil cylinder 6 is supplied with oil through the second one-way valve 8, which enters the rod cavity of the pressing oil cylinder 6 through the third variable oil port and the fourth variable oil port, in this process, if the oil pressure in the rod cavity of the pressing oil cylinder 6 is too large, it is easy to cause dangerous accidents such as explosion, therefore when the oil pressure is too large, the first overflow valve 12 can overflow.

[0038] In order to avoid personal injury during the working process of the pressing oil cylinder 6, an electrically controlled one-way cut-off valve 13 is further included, the electrically controlled one-way cut-off valve 13 is arranged between the first one-way valve 7 and the rodless cavity of the pressing oil cylinder 6, a protective door 16 is arranged on the injection molding machine, in this embodiment, a position sensor is arranged on the protective door 16, when the protective door 16 is not closed in place, the electrically controlled one-way cut-off valve 13 can disconnect the pipeline between the first one-way valve 7 and the rodless cavity of the pressing oil cylinder 6, so that the pressing oil cylinder 6 cannot normally press, avoiding personal injury, when the protective door 16 is closed in place, the electrically controlled one-way cut-off valve 13 can receive the signal of the position sensor, at this time, the electromagnet of the electrically controlled one-way cut-off valve 13 is powered, the electrically controlled one-way cut-off valve 13 is opened, and the first one-way valve 7 is normally communicated with the pressing oil cylinder 6.

[0039] In order to avoid the oil pressure between the first power unit 2 and the first oil inlet being too large, a second overflow valve 14 is further included, a second pipeline is arranged between the first power unit 2 and the first oil inlet, the second overflow valve 14 is in communication with the second pipeline, when the pressure is too large, the second overflow valve 14 can overflow, protecting the first power unit 2.

[0040] In order to avoid the excessive oil pressure between the second power unit 3 and the second oil inlet, a third overflow valve 15 is further arranged, a third pipeline is arranged between the second power unit 3 and the second oil inlet, the third overflow valve 15 is communicated with the third pipeline, and when the pressure is excessive, the third overflow valve 15 can overflow to protect the second power unit 3.

[0041] Of course, pressure gauges can also be arranged on the plurality of oil paths to monitor the pressure conditions of the plurality of oil paths in real time.

[0042] The technical scheme of the utility model is described in detail above with reference to the drawings, and the described embodiments are used to help understand the idea of the utility model. The specific embodiments described in the present text are merely examples of the spirit of the utility model. Those skilled in the art to which the utility model belongs can make various modifications or supplements to the described specific embodiments or replace them with similar ways, but will not deviate from the spirit of the utility model or exceed the scope defined by the appended claims.

[0043] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the utility model are merely used to explain the relative positional relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications will also change accordingly.

[0044] In addition, the descriptions such as "first", "second", "one" and the like in the utility model are merely for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the utility model, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0045] In the utility model, unless otherwise specifically defined and limited, the terms "connection", "fixation" and the like should be understood broadly, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically limited. For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0046] In addition, the technical solutions of various embodiments of the utility model can be combined with each other, but must be based on that a person having ordinary skill in the art can realize, when the combination of technical solutions appears mutual contradiction or cannot be realized, it should be considered that the combination of such technical solutions does not exist, also not within the protection scope required by the utility model.

Claims

1. A hydraulic system for controlling the BMC pressing device of an injection molding machine, characterized in that: It includes an oil tank, a first power unit, a second power unit, a first reversing valve, a second reversing valve and a pressing oil cylinder, wherein the oil inlets of the first power unit and the second power unit are both connected to the oil tank; The first reversing valve is provided with a first oil inlet, a second oil inlet and a first oil outlet, the first oil outlet is connected to the first oil inlet or the second oil inlet, the oil outlet of the first power unit is connected to the first oil inlet, and the oil outlet of the second power unit is connected to the second oil inlet; The second reversing valve is provided with a third oil inlet, a first oil return port, a first variable oil port and a second variable oil port. When the third oil inlet is connected to the first variable oil port, the first oil return port is connected to the second variable oil port. When the third oil inlet is connected to the second variable oil port, the first oil return port is connected to the first variable oil port, the first oil outlet is connected to the third oil inlet, the first variable oil port is connected to the rodless chamber of the pressing cylinder, and the second variable oil port is connected to the rod chamber of the pressing cylinder. The power of the second power unit is less than the power of the first power unit.

2. A hydraulic system for controlling a BMC pressing device of an injection molding machine according to claim 1, characterized in that: A first one-way valve is provided between the first variable oil port and the rodless chamber of the pressing cylinder, and the opening of the first one-way valve is toward the rodless chamber of the pressing cylinder. A second one-way valve is provided between the second variable oil port and the rod chamber of the pressing cylinder, and the opening of the second one-way valve is toward the rod chamber of the pressing cylinder.

3. A hydraulic system for controlling a BMC pressing device of an injection molding machine according to claim 2, characterized in that: It also includes a first open pipe, one end of which is connected to the first variable oil port, and the other end of the first open pipe is connected to the second one-way valve. When oil is discharged from the first variable oil port, the second one-way valve can be opened through the first open pipe.

4. A hydraulic system for controlling a BMC pressing device of an injection molding machine according to claim 2, characterized in that: It also includes a second open pipe, one end of the second open pipe is connected to the second variable oil port, and the other end of the second open pipe is connected to the first one-way valve. When oil is discharged from the second variable oil port, the first one-way valve can be opened through the second open pipe.

5. The hydraulic system for controlling the BMC pressing device of an injection molding machine according to claim 2, characterized in that: It also includes a differential valve, which is provided with a third variable oil port, a fourth variable oil port and a second oil return port. The fourth variable oil port can be connected to the third variable oil port or the second oil return port. The third variable oil port is connected to the oil port of the second one-way valve close to the rod chamber of the pressing cylinder, the fourth variable oil port is connected to the rod chamber of the pressing cylinder, and the second oil return port is connected to the first one-way valve and the pipeline between the rodless chamber of the pressing cylinder.

6. A hydraulic system for controlling a BMC pressing device of an injection molding machine according to claim 5, characterized in that: The differential valve is provided with a first electromagnet. When the first electromagnet is energized, the fourth variable oil port is connected to the second oil return port. When the first electromagnet is de-energized, the fourth variable oil port is connected to the third variable oil port.

7. The hydraulic system for controlling the BMC pressing device of an injection molding machine according to claim 5, characterized in that: It also includes a first overflow valve, a first pipeline is provided between the third variable oil port and the oil port of the second one-way valve, and the first overflow valve is communicated with the first pipeline.

8. The hydraulic system for controlling the BMC pressing device of an injection molding machine according to claim 2, characterized in that: It also includes an electrically controlled one-way shut-off valve, which is located between the first one-way valve and the rodless chamber of the pressure cylinder. The electrically controlled one-way shut-off valve can receive a switching signal from the protective door of the injection molding machine and can block the first one-way valve and the rodless chamber of the pressure cylinder.

9. The hydraulic system for controlling the BMC pressing device of an injection molding machine according to claim 1, characterized in that: It also includes a second overflow valve, a second pipeline is provided between the first power unit and the first oil inlet, and the second overflow valve is connected to the second pipeline.

10. The hydraulic system for controlling the BMC pressing device of an injection molding machine according to claim 1, characterized in that: It also includes a third overflow valve. A third pipeline is provided between the second power unit and the second oil inlet. The third overflow valve is connected to the third pipeline.

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