Energy-saving hydraulic system of hollow forming machine

Abstract

The utility model discloses an energy-saving hydraulic system of a hollow forming machine, which comprises a low-pressure large-flow pump and a high-pressure small-flow pump which are connected with each other and connected with an energy accumulator and an alternating current motor in series. A low-pressure large-flow pump control module and a high-pressure small-flow pump control module are respectively arranged on the low-pressure large-flow pump and the high-pressure small-flow pump; the output end of the low-pressure large-flow pump and the output end of the high-pressure small-flow pump are connected with a blowing needle screwing-out control module, an expansion control module, a blowing control module, a mold locking control module, a mold closing control module and an injection control module. And the energy efficiency of the system is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of blow molding machinery, in particular to an energy-saving hydraulic system of a hollow molding machine. Background Art

[0002] The operating steps of a blow molding machine include injection, mold closing, clamping, inflation, expansion, and needle removal. To improve production efficiency, injection and mold closing operations must be fast, requiring a high flow rate from the power source. The inflation and holding pressure phase accounts for approximately two-thirds of the entire process. To prevent the mold from expanding during inflation, the mold clamping requires high pressure. During this phase, virtually no flow input is required, and the speed and pressure requirements for inflation, expansion, and needle removal are low. Small and medium-sized blow molding machines generally use a hydraulic system powered by a single high-pressure, high-flow pump. This hydraulic system is powered by an AC motor driving a high-pressure, high-flow metering pump. The pressure for each system operation (injection, mold closing, clamping, inflation, expansion, and needle removal) is set by a solenoid relief valve. Injection and mold closing require a low-pressure, high-flow pump from the oil pump, while clamping and holding pressure require a high-pressure, low-flow pump from the oil pump. Inflation, expansion, and needle removal require low flow and pressure. Because the power source of the hydraulic system is an AC motor + a high-pressure, high-flow quantitative oil pump, it can only provide a fixed flow and pressure output. When working, it outputs high pressure and large flow, and the motor output power is very high, resulting in a lot of power waste. The wasted power is converted into heat energy, causing the oil tank to heat up seriously.

[0003] To avoid the above situation, some blow molding machines use a dual-pump oil supply system. This hydraulic system consists of an AC motor driving a high-pressure, low-flow, and a low-pressure, high-flow dual-metering pump. The pressure of the system actions (injection and mold clamping) is set by a solenoid overflow valve, and the pressure of the system actions (clamping, inflation, expansion, and needle extraction) is also set by a solenoid overflow valve. This hydraulic system has solved the problems existing in the hydraulic system to a certain extent. Injection and mold clamping are provided by a low-pressure, high-flow metering pump, while the remaining actions are provided by a high-pressure, low-flow pump. However, the inflation and holding pressure process accounts for two-thirds of the entire process. During this process, basically no flow input is required. The speed of the AC motor and high-pressure, low-flow pump cannot reach very low, so there is still a significant power loss. In addition, the pressure and flow required for other actions, except for clamping, are not high, which also causes a certain amount of power loss, resulting in relatively low production efficiency. Utility Model Content

[0004] In view of the above defects or shortcomings, the purpose of the present invention is to provide an energy-saving hydraulic system for a hollow molding machine.

[0005] In order to achieve the above objectives, the technical solution of the utility model is:

[0006] An energy-saving hydraulic system for a hollow molding machine comprises: a low-pressure, high-flow pump and a high-pressure, low-flow pump connected to each other, an accumulator and an AC motor being connected in series to the low-pressure, high-flow pump and the high-pressure, low-flow pump, and a low-pressure, high-flow pump control module and a high-pressure, low-flow pump control module being provided on the low-pressure, high-flow pump and the high-pressure, low-flow pump, respectively; output ends of the low-pressure, high-flow pump and the high-pressure, low-flow pump are connected to a blow needle rotation control module, an expansion control module, a blowing control module, a mold locking control module, a mold closing control module, and an injection control module.

[0007] The low-pressure, high-flow pump control module includes: a first electromagnetic reversing valve installed on the low-pressure, high-flow pump, and a first one-way valve is arranged between the low-pressure, high-flow pump and the high-pressure, low-flow pump; the high-pressure, low-flow pump control module includes: a first electro-hydraulic reversing valve installed on the high-pressure, low-flow pump and an unloading overflow valve for setting the oil filling pressure.

[0008] The blow needle rotation control module includes: a second electromagnetic reversing valve and a second one-way throttle valve, and the second electromagnetic reversing valve is connected to a low-pressure high-flow pump and a high-pressure low-flow pump respectively.

[0009] The expansion control module includes: a third electromagnetic reversing valve and a third one-way throttle valve, and the second electromagnetic reversing valve is connected to the low-pressure high-flow pump and the high-pressure low-flow pump respectively.

[0010] The inflation control module includes: a fourth electromagnetic reversing valve and a fourth one-way throttle valve, and the second electromagnetic reversing valve is connected to the low-pressure high-flow pump and the high-pressure low-flow pump respectively.

[0011] The locking control module includes: a first large flow electro-hydraulic reversing valve and a fifth one-way throttle valve, and the fifth electromagnetic reversing valve is connected to a low-pressure large flow pump and a high-pressure small flow pump respectively.

[0012] The mold clamping control module includes a proportional reversing valve.

[0013] The injection control module includes: a second large-flow electro-hydraulic reversing valve and a sixth one-way throttle valve, and the sixth one-way throttle valve is connected to the low-pressure large-flow pump and the high-pressure small-flow pump respectively.

[0014] The return oil of the low-pressure large-flow pump and the high-pressure small-flow pump is connected in series to return to the oil tank, and the accumulator is equipped with an accumulator safety valve for filling and unloading oil.

[0015] An oil suction filter, an oil pressure filter, an oil return filter and a cooler are installed on the oil circuits of the low-pressure high-flow pump and the high-pressure low-flow pump.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] This utility model provides an energy-saving hydraulic system for a blow molding machine. It is powered by an AC motor, which drives a high-pressure, low-flow, dual-pump and a low-pressure, high-flow dual-pump, along with an accumulator. The oil outlets of the large and small pumps are separated by a one-way valve, and the large and small pumps and the accumulator's oil outlets are combined to supply oil to various actuators. Actuator actions include injection, mold closing, mold locking, inflation, expansion, and needle rotation. The direction of each actuator is controlled by an electrically controlled solenoid reversing valve and a proportional reversing valve, and speed regulation is performed by a one-way throttle valve. The oil return lines of the large and small pumps are connected in series and return directly to the oil tank. The accumulator's oil return is controlled by an accumulator safety shut-off valve. The pressure of the large pump is controlled by a solenoid relief valve, while the oil pressure of the small pump and accumulator is controlled by an unloading relief valve. When the system requires rapid, high-flow rates, the large and small pumps and accumulator supply oil together. When the system is inflating and maintaining pressure, the large and small pumps are unloaded, and the accumulator maintains pressure. If the accumulator pressure is insufficient, the unloading relief valve opens, allowing the small pump to replenish pressure. The hydraulic system only needs to select a small-power motor to meet the motion requirements, reasonably coordinating supply and demand, and greatly improving the energy efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of the energy-saving hydraulic system of the hollow molding machine of the utility model;

[0019] Figure 2 This is the hardware connection diagram of the energy-saving hydraulic system of the utility model hollow molding machine;

[0020] Figure 3 This is a block diagram of the energy-saving hydraulic system of the utility model hollow molding machine.

[0021] In the figure, 1. motor; 2. low-pressure, high-flow pump; 2. high-pressure, low-flow pump; 4. first one-way valve; 5. first electromagnetic relief valve; 6. unloading relief valve; 7. first electro-hydraulic reversing valve; 8. sixth one-way throttle valve; 9. second large-flow electro-hydraulic reversing valve; 10. proportional reversing valve; 11. fifth one-way throttle valve; 12. first large-flow electro-hydraulic reversing valve; 13. fourth one-way throttle valve; 14. fourth electromagnetic reversing valve; 15. third one-way throttle valve; 16. third electromagnetic reversing valve; 17. second one-way throttle valve; 18. second electromagnetic reversing valve; 19. high-pressure filter; 20. cooler; 21. return oil filter; 22. air filter; 23. oil suction filter; 24. accumulator safety shut-off valve; 25. accumulator. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0023] like Figure 1-3 As shown, the utility model provides an energy-saving hydraulic system for a hollow molding machine, comprising: a low-pressure, high-flow pump 2 and a high-pressure, low-flow pump 3 connected to each other, an accumulator 25 and an AC motor 1 being connected in series on the low-pressure, high-flow pump 2 and the high-pressure, low-flow pump 3, and a low-pressure, high-flow pump control module and a high-pressure, low-flow pump control module being respectively provided on the low-pressure, high-flow pump 2 and the high-pressure, low-flow pump 3; the output ends of the low-pressure, high-flow pump 2 and the high-pressure, low-flow pump 3 are connected to a blow needle rotation control module, an expansion control module, a blowing control module, a mold locking control module, a mold closing control module, and an injection control module.

[0024] Specifically, in the present invention, the low-pressure, high-flow pump control module includes: a first electromagnetic reversing valve 5 installed on the low-pressure, high-flow pump 2; a first check valve 4 is provided between the low-pressure, high-flow pump 2 and the high-pressure, low-flow pump 3; and the high-pressure, low-flow pump control module includes: a first electro-hydraulic reversing valve 7 installed on the high-pressure, low-flow pump 3; and an unloading relief valve 6 for setting the oil filling pressure. It should be noted that the operating pressure of the low-pressure, high-flow pump 2 is ≤7MPa and the flow rate is ≥100L / min, while the operating pressure of the high-pressure, low-flow pump 3 is ≥10MPa and the flow rate is ≤20L / min.

[0025] For example, the blow needle rotation control module, expansion control module, inflation control module, mold locking control module, mold closing control module, and injection control module in the present invention specifically include:

[0026] The blow needle rotation control module includes: a second electromagnetic reversing valve 18 and a second one-way throttle valve 17. The second electromagnetic reversing valve 18 is connected to the low-pressure high-flow pump 2 and the high-pressure low-flow pump 3 respectively.

[0027] The expansion control module includes: a third electromagnetic reversing valve 16 and a third one-way throttle valve 15. The second electromagnetic reversing valve 16 is connected to the low-pressure high-flow pump 2 and the high-pressure low-flow pump 3 respectively.

[0028] The inflation control module includes: a fourth electromagnetic reversing valve 14 and a fourth one-way throttle valve 13. The second electromagnetic reversing valve 15 is connected to the low-pressure high-flow pump 2 and the high-pressure low-flow pump 3 respectively.

[0029] The locking control module includes: a first large flow electro-hydraulic reversing valve 12 and a fifth one-way throttle valve 11. The fifth electromagnetic reversing valve 11 is connected to the low-pressure large flow pump 2 and the high-pressure small flow pump 3 respectively.

[0030] The mold clamping control module includes: a proportional reversing valve 10. A first large flow electro-hydraulic reversing valve 12 has a flow rate of generally ≥150 L / min.

[0031] The injection control module includes: a second large flow electro-hydraulic reversing valve 9 and a sixth one-way throttle valve 8. The sixth one-way throttle valve 8 is connected to the low-pressure large flow pump 2 and the high-pressure small flow pump 3 respectively.

[0032] Preferably, in the present invention, the return oil of the low-pressure, high-flow pump 2 and the high-pressure, low-flow pump 3 is connected in series to return to the oil tank, and an accumulator safety valve 24 for filling and unloading oil is installed on the accumulator 25. An oil suction filter 23, an oil pressure filter 19, an oil return filter 21 and a cooler 20 are installed in the oil circuit of the low-pressure, high-flow pump 2 and the high-pressure, low-flow pump 3.

[0033] The working process and principle of this utility model are as follows:

[0034] like Figure 1 As shown, the hydraulic system in this utility model performs actions including injection, mold closing, mold locking, inflation, expansion, and needle removal. The direction of the control actuators for inflation, expansion, and needle removal is controlled by the fourth solenoid reversing valve 14, the third solenoid reversing valve 16, and the second solenoid reversing valve 18, while the speed is controlled by the fourth one-way throttle valve 13, the second solenoid reversing valve 15, and the second one-way throttle valve 17. For injection and mold closing operations requiring rapid operation, the direction of the second high-flow electro-hydraulic reversing valve 9 and the first high-flow electro-hydraulic reversing valve 12 is controlled, while the speed is controlled by the sixth one-way throttle valve 8 and the fifth solenoid reversing valve 11. For mold closing speed conversion, a proportional reversing valve 10 is used. The oil supply for the above actions is provided by an AC motor 1 driving a low-pressure, high-flow pump 2, a high-pressure, low-flow pump 3, and an accumulator 25, which form a series oil supply. The accumulator 25 is charged by the small pump 3, with the charging pressure set by the unloading relief valve 6. When the charging pressure reaches the set value, the high-pressure, low-flow pump 3 is unloaded. The pressure of the low-pressure, high-flow pump 2 is set by the first solenoid reversing valve 5. The oil supply between the accumulator 25 and the high-pressure, low-flow pump 3 is remotely controlled via the first electro-hydraulic reversing valve 7 to switch the oil supply. To prevent the pressure oil from the high-pressure, low-flow pump 3 from entering the low-pressure, high-flow pump 2, a first check valve 4 is installed in the oil circuit between the two pumps to separate the large and small pumps. When injection and mold closing operations require rapid operation, oil is supplied simultaneously by the large low-pressure, high-flow pump 2, the high-pressure, low-flow pump 3, and the accumulator 25. During mold clamping and holding pressure, the low-pressure, high-flow pump 2 and the high-pressure, low-flow pump 3 are unloaded, and the accumulator 25 supplies oil to maintain pressure. If the holding pressure is insufficient, the high-pressure, low-flow pump 3 is promptly replenished through the unloading relief valve. Other operations such as inflation, expansion, and needle rotation are satisfied by the low-pressure, high-flow pump 2. The return oil from low-pressure, high-flow pump 2 and high-pressure, low-flow pump 3 is connected in series and returns to the fuel tank. The filling and unloading of accumulator 25 is controlled by accumulator safety valve 24. To ensure oil cleanliness, the hydraulic system is equipped with an oil suction filter 23, a pressure filter 19, and a return filter 21. To prevent the oil from overheating, a cooler 20 is installed, and an air filter prevents air from entering the fuel tank during refueling.

[0035] For those skilled in the art, it is obvious that the above-mentioned specific examples are only preferred embodiments of the present invention. Therefore, any improvements and changes that may be made by those skilled in the art to certain parts of the present invention still reflect the principles of the present invention and still achieve the purpose of the present invention, and all fall within the scope of protection of the present invention.

Claims

1. An energy-saving hydraulic system for a hollow molding machine, characterized in that: include: A low-pressure, high-flow pump (2) and a high-pressure, low-flow pump (3) are connected to each other, an accumulator (25) and an AC motor (1) are connected in series to the low-pressure, high-flow pump (2) and the high-pressure, low-flow pump (3), and a low-pressure, high-flow pump control module and a high-pressure, low-flow pump control module are provided on the low-pressure, high-flow pump (2) and the high-pressure, low-flow pump (3), respectively; and output ends of the low-pressure, high-flow pump (2) and the high-pressure, low-flow pump (3) are connected to a blow needle rotation control module, an expansion control module, a blowing control module, a mold locking control module, a mold closing control module, and an injection control module.

2. The energy-saving hydraulic system of the hollow molding machine according to claim 1, characterized in that: The low-pressure, high-flow pump control module comprises: a first electromagnetic reversing valve (5) installed on the low-pressure, high-flow pump (2); a first one-way valve (4) is provided between the low-pressure, high-flow pump (2) and the high-pressure, low-flow pump (3); and the high-pressure, low-flow pump control module comprises: a first electro-hydraulic reversing valve (7) installed on the high-pressure, low-flow pump (3) and an unloading relief valve (6) for setting the oil filling pressure.

3. The energy-saving hydraulic system of the hollow molding machine according to claim 1, characterized in that: The blow needle rotation control module comprises: a second electromagnetic reversing valve (18) and a second one-way throttle valve (17); the second electromagnetic reversing valve (18) is connected to a low-pressure high-flow pump (2) and a high-pressure low-flow pump (3) respectively.

4. The energy-saving hydraulic system of the hollow molding machine according to claim 3, characterized in that: The expansion control module comprises: a third electromagnetic reversing valve (16) and a third one-way throttle valve (15); the second electromagnetic reversing valve (16) is connected to the low-pressure high-flow pump (2) and the high-pressure low-flow pump (3) respectively.

5. The energy-saving hydraulic system of the hollow molding machine according to claim 4, characterized in that: The inflation control module comprises: a fourth electromagnetic reversing valve (14) and a fourth one-way throttle valve (13); the second electromagnetic reversing valve (15) is connected to the low-pressure high-flow pump (2) and the high-pressure low-flow pump (3) respectively.

6. The energy-saving hydraulic system of the hollow molding machine according to claim 5, characterized in that: The locking control module comprises: a first large-flow electro-hydraulic reversing valve (12) and a fifth one-way throttle valve (11); the fifth electromagnetic reversing valve (11) is connected to a low-pressure large-flow pump (2) and a high-pressure small-flow pump (3) respectively.

7. The energy-saving hydraulic system of the hollow molding machine according to claim 6, characterized in that: The mold closing control module comprises a proportional reversing valve (10).

8. The energy-saving hydraulic system of the hollow molding machine according to claim 7, characterized in that: The injection control module comprises: a second large flow electro-hydraulic reversing valve (9) and a sixth one-way throttle valve (8), wherein the sixth one-way throttle valve (8) is connected to the low-pressure large flow pump (2) and the high-pressure small flow pump (3) respectively.

9. The energy-saving hydraulic system of the hollow molding machine according to claim 8, characterized in that: The oil returns of the low-pressure high-flow pump (2) and the high-pressure low-flow pump (3) are connected in series and return to the oil tank. An accumulator safety valve (24) for filling and unloading oil is installed on the accumulator (25).

10. The energy-saving hydraulic system of the hollow molding machine according to claim 9, characterized in that: An oil suction filter (23), an oil pressure filter (19), an oil return filter (21) and a cooler (20) are installed on the oil circuits of the low-pressure high-flow pump (2) and the high-pressure low-flow pump (3).

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