Hydraulic driving system of vertical injection molding machine and injection molding machine

Abstract

The invention relates to the field of injection molding, in particular to a vertical injection molding machine hydraulic driving system and an injection molding machine. In the glue melting process, raw materials are in a molten and plasticized state, the screw is pushed to retreat along with continuous accumulation of the raw materials, namely, the screw moves upwards, at the moment, a coil YA1 of the glue injecting and melting control valve is powered on, a port P and a port B of the glue injecting and melting control valve are communicated, a port A and a port T of the glue injecting and melting control valve are communicated, and an auxiliary pump provides pressure oil which enters a rodless cavity of a glue injecting oil cylinder; the auxiliary pump provides constant pressure for a rodless cavity of the glue injecting and melting oil cylinder and is used for balancing influences caused by the weight of a motor and the weight of a tail plate, a rod cavity of the glue injecting oil cylinder is connected with the back pressure valve, and the back pressure valve and the auxiliary pump assembly are matched to enable the rodless cavity and the rod cavity of the glue injecting oil cylinder to be in a dynamic balance state. The back pressure valve more accurately controls the pressure of a rod cavity of the glue injection oil cylinder, and the influence caused by the pressure brought by a motor and the like is eliminated through the auxiliary pump.

Description

Technical Field

[0001] The invention relates to the field of injection molding, and in particular to a hydraulic drive system of a vertical injection molding machine and an injection molding machine. Background Art

[0002] The injection molding machine is equipped with a hydraulic drive structure, which includes a main pump, a shot cylinder, a shot-shift cylinder, a reversing valve group, a melt motor, etc. The shot cylinder, the shot-shift cylinder, and the melt motor are connected to the oil inlet and return lines through their corresponding reversing valve groups. However, the above hydraulic drive structure has the following disadvantages:

[0003] When the injection molding machine is melting glue on the injection platform, if the injection cylinder of the injection molding machine is set vertically, the oil of the main pump is fully supplied to the motor to achieve the purpose of full-speed melting glue. While the motor drives the screw to melt glue at full speed, the rubber pushes the motor upward. By setting the back pressure value of the injection cavity, the material is evenly compacted. Affected by the gravity of the motor and the tail plate of the motor, the compaction state of the material is uncontrollable and the product quality cannot be guaranteed.

[0004] Therefore, there is an urgent need for a hydraulic drive system for a vertical injection molding machine to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to provide a hydraulic drive system for a vertical injection molding machine, which can ensure more accurate control of the compaction state of molten material.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, a hydraulic drive system for a vertical injection molding machine is provided, comprising:

[0008] A main pump, wherein an oil inlet of the main pump is connected to the oil tank;

[0009] The shooting control assembly includes a shooting control valve and a shooting oil cylinder, wherein the oil inlet of the shooting control valve is connected to the oil outlet of the main pump, and the shooting control valve is used to control the oil inlet of the main pump to selectively connect to the rod chamber or the rodless chamber of the shooting oil cylinder;

[0010] A motor, wherein the motor is used to connect the screw inside the melt barrel;

[0011] The injection control assembly includes an injection melt control valve and an injection cylinder. The injection control valve is used to control the oil inlet of the main pump to selectively connect to the rod chamber of the injection cylinder or the oil inlet of the motor. The tail plate carrying the motor is connected to the piston rod of the injection cylinder.

[0012] A release control assembly, comprising a release control valve, wherein the release control valve is used to control the rodless chamber of the injection cylinder to selectively communicate with the oil tank or the oil outlet of the main pump;

[0013] Auxiliary pump assembly, the auxiliary pump assembly at least comprises an auxiliary pump, the oil outlet of the auxiliary pump is communicated with the rodless chamber of the injection cylinder;

[0014] A back pressure valve, wherein the oil inlet of the back pressure valve is communicated with the oil return port of the injection control valve, and the oil outlet of the back pressure valve is communicated with the oil tank.

[0015] As a preferred technical solution of the hydraulic drive system of the above-mentioned vertical injection molding machine, the auxiliary pump assembly also includes a one-way valve, the oil outlet of the one-way valve is connected to the rodless chamber of the injection cylinder, the oil inlet of the one-way valve is connected to the oil outlet of the auxiliary pump, and the one-way valve only allows the oil provided by the auxiliary pump to enter the rodless chamber of the injection cylinder.

[0016] As a preferred technical solution of the hydraulic drive system of the vertical injection molding machine, the shooting control assembly further includes a hydraulic lock, which connects the shooting cylinder and the shooting control valve.

[0017] As a preferred technical solution of the hydraulic drive system of the vertical injection molding machine, a filter is also included, and the oil inlet of the main pump and the oil inlet of the auxiliary pump are both connected to the filter.

[0018] As a preferred technical solution of the hydraulic drive system of the vertical injection molding machine, the rodless cavity of the injection cylinder is provided with a first pressure sensor for detecting the pressure of the rodless cavity.

[0019] As a preferred technical solution of the hydraulic drive system of the vertical injection molding machine, the rod cavity of the injection cylinder is provided with a second pressure sensor for detecting the rod cavity of the injection cylinder.

[0020] As a preferred technical solution of the hydraulic drive system of the vertical injection molding machine, the injection control valve is a three-position four-way solenoid valve; and / or,

[0021] The injection and melt control valve is a three-position four-way solenoid valve; and / or,

[0022] The release and retraction control valves are all three-position four-way solenoid valves.

[0023] As an optimal technical solution of the hydraulic drive system of the vertical injection molding machine, it also includes a relief valve, the oil inlet of the relief valve is connected to the oil outlet of the main pump, and the oil outlet of the relief valve is connected to the oil return port of the oil tank.

[0024] As a preferred technical solution of the hydraulic drive system of the vertical injection molding machine, the auxiliary pump is a constant pressure variable displacement pump.

[0025] In a second aspect, an injection molding machine is provided, comprising the hydraulic drive system for the vertical injection molding machine described in any of the above schemes.

[0026] The present invention has at least the following beneficial effects:

[0027] The hydraulic drive system and injection molding machine of the vertical injection molding machine provided by the present invention, in the process of melting glue, the raw materials are in a melted and plasticized state, and as the raw materials continue to accumulate, the screw is pushed back, that is, the screw moves upward, at this time, the coil YA1 of the injection molding control valve is energized, the P port of the injection molding control valve is connected to the B port, the A port of the injection molding control valve is connected to the T port, and the auxiliary pump provides pressure oil to enter the rodless cavity of the injection cylinder, and the auxiliary pump provides a constant pressure for the rodless cavity of the injection cylinder to balance the influence of the weight of the motor and the tail plate. In order to avoid the screw from retreating too fast, the rod cavity of the injection cylinder is connected to the back pressure valve, and the back pressure valve and the auxiliary pump assembly cooperate to realize that the rodless cavity and the rod cavity of the injection cylinder are in a dynamic balance state, so that the molten raw materials can be evenly compacted, and the density, weight and related dimensions of the manufactured products are more stable. The present invention eliminates the influence of the pressure brought by the motor and the tail plate on which the motor is installed through the auxiliary pump, so that the back pressure control is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0029] Figure 1 A hydraulic principle diagram of a hydraulic drive system for a vertical injection molding machine provided by an embodiment of the present invention;

[0030] Figure 2 A partial schematic diagram of the injection control component, the release control component and the injection control component provided in an embodiment of the present invention.

[0031] In the figure:

[0032] 1. Main pump; 2. Motor; 3. Injection control valve; 4. Injection cylinder; 5. Injection and melting control valve; 6. Injection cylinder; 7. Release control valve; 8. Auxiliary pump; 9. Back pressure valve; 11. Check valve; 12. Hydraulic lock; 13. Filter; 14. First pressure sensor; 15. Second pressure sensor; 16. Overflow valve; 17. Oil tank; 100. Screw. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0034] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; 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. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0036] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0037] like Figure 1 and Figure 2As shown, an embodiment of the present invention provides a hydraulic drive system for a vertical injection molding machine, the hydraulic drive system for a vertical injection molding machine includes a main pump 1, a motor 2, a shot shift control component, a glue injection control component, a release control component, an auxiliary pump component 8 and a back pressure valve 9, wherein the oil inlet of the main pump 1 is connected to the oil tank 17, the motor 2 is used to connect with the screw 100, the shot shift control component includes a shot shift control valve 3 and a shot shift cylinder 4, the oil inlet of the shot shift control valve 3 is connected to the oil outlet of the main pump 1, and the shot shift control valve 3 is used to control the oil inlet of the main pump 1 to selectively connect to the rod chamber or the rodless chamber of the shot shift cylinder 4; The glue control component includes a glue injection and melt control valve 5 and a glue injection cylinder 6. The glue injection and melt control valve 5 is used to control the oil inlet of the main pump 1 to selectively connect with the rod chamber of the glue injection cylinder 6 or the oil inlet of the motor 2; the loosening and retreating control component includes a loosening and retreating control valve 7. The loosening and retreating control valve 7 is used to control the rodless chamber of the glue injection cylinder 6 to selectively connect with the oil tank 17 or the oil outlet of the main pump 1; the auxiliary pump component 8 includes at least an auxiliary pump 8, and the oil outlet of the auxiliary pump 8 is connected with the rodless chamber of the injection cylinder 4; the oil inlet of the back pressure valve 9 is connected with the oil return port of the glue injection and melt control valve 5, and the oil outlet of the back pressure valve 9 is connected with the oil tank 17.

[0038] In the hydraulic drive system of the vertical injection molding machine provided by the embodiment of the present invention, during the melting process, the raw materials are in a melted and plasticized state. As the raw materials continue to accumulate, the screw 100 is pushed back, that is, the screw 100 moves upward. At this time, the coil YA1 of the injection melt control valve 5 is energized, and the P port of the injection melt control valve 5 is connected to the B port, and the A port of the injection melt control valve 5 is connected to the T port (i.e., the return oil port). The auxiliary pump 8 provides pressure oil to enter the rodless cavity of the injection cylinder 6. The auxiliary pump 8 provides a constant pressure for the rodless cavity of the injection cylinder 6 to balance the influence of the weight of the motor 2 and the tail plate. In order to prevent the screw 100 from retreating too fast, the rod cavity of the injection cylinder 6 is connected to the back pressure valve 9. The back pressure valve 9 and the auxiliary pump assembly cooperate to realize that the rodless cavity and the rod cavity of the injection cylinder 6 are in a dynamic balance state, so that the molten raw materials can be evenly compacted, and the density, weight and related dimensions of the manufactured products are more stable. The present invention eliminates the influence of the pressure brought by the motor 2 and the tail plate on which the motor 2 is installed through the auxiliary pump 8, so that the back pressure control is more accurate.

[0039] There are at least two injection cylinders 6, and the piston rod of each injection cylinder 6 is connected to the tail plate, wherein the rodless chambers of the injection cylinders 6 are interconnected, and the rod chambers of the injection cylinders 6 are interconnected. Such an arrangement can ensure that the injection cylinders 6 can stably support the tail plate, and the pressure of each part of the rodless chamber is balanced, and the pressure of each part of the rod chamber is also balanced, so as to avoid the tail plate tilting and causing the screw 100 to tilt.

[0040] Furthermore, the auxiliary pump assembly further includes a one-way valve 11, the oil outlet of the one-way valve 11 is connected to the rodless chamber of the injection cylinder 6, the oil inlet of the one-way valve 11 is connected to the oil outlet of the auxiliary pump 8, and the one-way valve 11 only allows the oil provided by the auxiliary pump 8 to enter the rodless chamber of the injection cylinder 6. The setting of the one-way valve 11 can prevent the oil in the injection cylinder 6 from entering the auxiliary pump 8, thereby ensuring the amount of oil in the injection cylinder 6.

[0041] In some embodiments, the auxiliary pump 8 is a constant pressure variable pump. The constant pressure variable pump can adjust the flow rate of the hydraulic oil entering the rodless chamber of the injection cylinder 6. For example, the auxiliary pump 8 includes a pump body and a swash plate angle adjustment component. Since the swash plate angle adjustment component is a prior art for adjusting the oil volume, it will not be described in detail here.

[0042] In some embodiments, the shooting control assembly further includes a hydraulic lock 12, which connects the shooting cylinder 4 and the shooting control valve 3. The setting of the hydraulic lock 12 can ensure that the shooting cylinder 4 maintains pressure, thereby ensuring that the entire shooting platform will not fall during the shooting process. The specific structure of the hydraulic lock 12 is existing and will not be described in detail.

[0043] In some embodiments, the hydraulic drive system of the vertical injection molding machine further includes a filter 13, and the oil inlet of the main pump 1 and the oil inlet of the auxiliary pump 8 are both connected to the filter 13. The setting of the filter 13 can prevent impurities in the hydraulic oil from entering the main pump 1 and the auxiliary pump 8, avoid the main pump 1 and the auxiliary pump 8 from being worn by impurities, and improve the safety of the main pump 1 and the auxiliary pump 8.

[0044] In some embodiments, the rodless cavity of the injection cylinder 6 is provided with a first pressure sensor 14 for detecting the pressure of the rodless cavity, and the rod cavity of the injection cylinder 6 is provided with a second pressure sensor 15 for detecting the pressure of the rod cavity. The first pressure sensor 14 is used to detect the pressure in the rodless cavity of the injection cylinder 6, and the second pressure sensor 15 is used to detect the pressure in the rod cavity of the injection cylinder 6, so as to obtain the pressure in the rodless cavity and the rod cavity of the injection cylinder 6 in real time, and control the auxiliary pump 8 and the injection melt control valve 5 to work according to the obtained pressure.

[0045] For example, the displacement control valve 3 is a three-position four-way solenoid valve, so as to realize the switching needs corresponding to different oil cylinders.

[0046] For example, the injection and melt control valve 5 is a three-position four-way solenoid valve, so as to realize the switching needs corresponding to different oil cylinders.

[0047] For example, the release and retraction control valves 7 are all three-position four-way solenoid valves, so as to realize the switching needs corresponding to different oil cylinders.

[0048] In some embodiments, the hydraulic drive system of the vertical injection molding machine further includes a relief valve 16, the oil inlet of the relief valve 16 is connected to the oil outlet of the main pump 1, and the oil outlet of the relief valve 16 is connected to the oil return port of the oil tank 17. The relief valve 16 is used to ensure that the oil circuit pressure is constant when the rodless chamber of the injection cylinder 6 enters and exits the hydraulic oil, and to avoid the increase of the oil circuit pressure caused by the sudden increase of the oil flow, thereby realizing the precise control of the lifting and lowering of the injection cylinder 6.

[0049] Combination Figure 1 and Figure 2 As shown, the working process of the hydraulic drive system of the vertical injection molding machine is as follows:

[0050] The process of shooting platform advancement: the right position YA6 of the shooting shift control valve 3 is energized, and the high-pressure oil passes through the shooting shift control valve 3 and the hydraulic lock 12 and enters the rod chamber of the shooting shift cylinder 4. The oil in the rodless chamber of the shooting shift cylinder 4 passes through the hydraulic lock 12 and the shooting shift control valve 3 and returns to the oil tank 17.

[0051] The process of shooting platform advancement: the left position YA5 of the shooting shift control valve 3 is energized, and the high-pressure oil passes through the shooting shift control valve 3 and the hydraulic lock 12 and enters the rodless chamber of the shooting shift cylinder 4. The oil in the rod chamber of the shooting shift cylinder 4 passes through the hydraulic lock 12 and the shooting shift control valve 3 and returns to the oil tank 17.

[0052] Injection process:

[0053] The right position YA2 of the injection and melt control valve 5 is energized, and the high-pressure oil enters the rod chamber of the injection cylinder 6 through the injection and melt control valve 5. The oil in the rodless chamber is energized through the left position YA3 of the release control valve 7 and returns to the oil tank, completing the injection action.

[0054] Loosening process:

[0055] The right position YA4 of the release and retraction control valve 7 is energized, and the high-pressure oil enters the rodless chamber of the injection cylinder 6 through the release and retraction control valve 7. The oil in the rod chamber passes through the injection and melt control valve 5 and then returns to the oil tank 17 through the back pressure valve 9.

[0056] Melting process:

[0057] The auxiliary pump 8 provides pressure oil, which passes through the one-way valve 11 and then enters the rodless cavity of the injection and melt glue cylinder 6. The auxiliary pump 8 provides a constant pressure (weight of the motor 2 and the tail plate / area of ​​the rodless cavity of the injection and melt glue cylinder 6) to balance the influence of the weight of the motor 2 and the tail plate structure.

[0058] The high-pressure oil of the main pump 1 enters the motor 2 through the injection and melt control valve 5. At this time, the left position YA1 of the injection and melt control valve 5 is energized, and the back pressure of the rod chamber of the injection cylinder 6 is controlled by the set value of the back pressure valve 9.

[0059] The present invention provides an injection molding machine, including the hydraulic drive system of the vertical injection molding machine provided in this embodiment.

[0060] Since the injection molding machine includes a vertical injection molding machine hydraulic drive system, during the melting process, the raw materials are melted and plasticized. As the raw materials continue to accumulate, the screw 100 is pushed back, that is, the screw 100 moves upward. At this time, the coil YA1 of the injection melt control valve 5 is energized, the P port of the injection melt control valve 5 is connected to the B port, the A port of the injection melt control valve 5 is connected to the T port, and the auxiliary pump 8 provides pressure oil to enter the rodless cavity of the injection cylinder 6. The auxiliary pump 8 provides a constant pressure for the rodless cavity of the injection cylinder 6 to balance the influence of the motor 2 and the weight of the tail plate. In order to prevent the screw 100 from retreating too fast, the rod cavity of the injection cylinder 6 is connected to the back pressure valve 9. The back pressure valve 9 and the auxiliary pump assembly cooperate to realize that the rodless cavity and the rod cavity of the injection cylinder 6 are in a dynamic balance state, so that the molten raw materials can be evenly compacted, and the density, weight and related dimensions of the manufactured products are more stable. The present invention eliminates the influence of the pressure brought by the motor 2 and the tail plate on which the motor 2 is installed through the auxiliary pump 8, so that the back pressure control is more accurate.

[0061] Since the vertical injection molding machine hydraulic drive system is included, the injection molding machine of the embodiment of the present invention has all the advantages and beneficial effects of the above embodiments, which will not be described in detail here.

[0062] In addition, the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A hydraulic drive system for a vertical injection molding machine, characterized in that: include: A main pump (1), wherein an oil inlet of the main pump (1) is connected to an oil tank (17); The displacement control assembly comprises a displacement control valve (3) and a displacement oil cylinder (4), wherein the oil inlet of the displacement control valve (3) is connected to the oil outlet of the main pump (1), and the displacement control valve (3) is used to control the oil inlet of the main pump (1) to selectively connect to the rod chamber or the rodless chamber of the displacement oil cylinder (4); A motor (2), wherein the motor (2) is used to connect a screw (100) inside the melt tube; The injection control assembly comprises an injection melt control valve (5) and an injection cylinder (6), wherein the injection melt control valve (5) is used to control the oil inlet of the main pump (1) to selectively connect to the rod chamber of the injection cylinder (6) or the oil inlet of the motor (2), and the tail plate carrying the motor (2) is connected to the piston rod of the injection cylinder (6); A release control assembly, comprising a release control valve (7), wherein the release control valve (7) is used to control the rodless chamber of the injection cylinder (6) to selectively communicate with the oil tank (17) or the oil outlet of the main pump (1); A secondary pump assembly, the secondary pump assembly at least comprising a secondary pump (8), the oil outlet of the secondary pump (8) being in communication with the rodless chamber of the shooting oil cylinder (4); A back pressure valve (9), wherein the oil inlet of the back pressure valve (9) is communicated with the oil return port of the injection and melt control valve (5), and the oil outlet of the back pressure valve (9) is communicated with the oil tank (17).

2. The hydraulic drive system of a vertical injection molding machine according to claim 1, characterized in that: The auxiliary pump assembly further comprises a one-way valve (11), the oil outlet of the one-way valve (11) being in communication with the rodless chamber of the injection cylinder (6), the oil inlet of the one-way valve (11) being in communication with the oil outlet of the auxiliary pump (8), and the one-way valve (11) only allowing the oil provided by the auxiliary pump (8) to enter the rodless chamber of the injection cylinder (6).

3. The hydraulic drive system of the vertical injection molding machine according to claim 1, characterized in that: The shooting control assembly also includes a hydraulic lock (12), and the hydraulic lock (12) connects the shooting cylinder (4) and the shooting control valve (3).

4. The hydraulic drive system of a vertical injection molding machine according to claim 1, characterized in that: It also comprises a filter (13), and the oil inlet of the main pump (1) and the oil inlet of the auxiliary pump (8) are both connected to the filter (13).

5. The hydraulic drive system for a vertical injection molding machine according to any one of claims 1 to 4, characterized in that: The rodless chamber of the injection cylinder (6) is provided with a first pressure sensor (14) for detecting the pressure of the rodless chamber.

6. The hydraulic drive system for a vertical injection molding machine according to any one of claims 1 to 4, characterized in that: The rod chamber of the injection cylinder (6) is provided with a second pressure sensor (15) for detecting the pressure of the rod chamber of the injection cylinder (6).

7. The hydraulic drive system for a vertical injection molding machine according to any one of claims 1 to 4, characterized in that: The displacement control valve (3) is a three-position four-way solenoid valve; and / or, The injection and melt control valve (5) is a three-position four-way solenoid valve; and / or, The release and retraction control valves (7) are all three-position four-way solenoid valves.

8. The hydraulic drive system for a vertical injection molding machine according to any one of claims 1 to 4, characterized in that: It also comprises a relief valve (16), the oil inlet of the relief valve (16) being in communication with the oil outlet of the main pump (1), and the oil outlet of the relief valve (16) being in communication with the oil return port of the oil tank (17).

9. The hydraulic drive system of a vertical injection molding machine according to any one of claims 1 to 4, characterized in that: The auxiliary pump (8) is a constant pressure variable displacement pump.

10. An injection molding machine, characterized in that: It comprises a hydraulic drive system for a vertical injection molding machine as described in any one of claims 1 to 9.

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