阅读说明：本技术 一种注塑机用液压控制系统 (Hydraulic control system for injection molding machine ) 是由 肖建国 左可奇 胡宝全 徐存科 冯子亮 田杰峰 陈明铭 沈明聪 于 2021-08-18 设计创作，主要内容包括：本发明公开了一种注塑机用液压控制系统,包括油箱、能源单元和执行单元,特点是能源单元包括伺服驱动器、伺服电机和双向闭式泵,油箱给双向闭式泵供油,伺服电机由伺服驱动器驱动,双向闭式泵由伺服电机驱动,双向闭式泵的进油端与执行单元的回油端通过第一工作油路相连,双向闭式泵的出油端与执行单元的进油端通过第二工作油路相连。优点是结构简单、精密、高效且节能。(The invention discloses a hydraulic control system for an injection molding machine, which comprises an oil tank, an energy unit and an execution unit, and is characterized in that the energy unit comprises a servo driver, a servo motor and a bidirectional closed pump, the oil tank supplies oil to the bidirectional closed pump, the servo motor is driven by the servo driver, the bidirectional closed pump is driven by the servo motor, the oil inlet end of the bidirectional closed pump is connected with the oil return end of the execution unit through a first working oil path, and the oil outlet end of the bidirectional closed pump is connected with the oil inlet end of the execution unit through a second working oil path. The device has the advantages of simple structure, precision, high efficiency and energy conservation.)

1. The utility model provides a hydraulic control system for injection molding machine, includes oil tank, energy unit and execution unit, its characterized in that the energy unit include servo driver, servo motor and two-way closed pump, the oil tank gives two-way closed pump mend oil, servo motor by servo driver drive, two-way closed pump by servo motor drive, the oil feed end of two-way closed pump with execution unit's the end that returns oil link to each other through first working oil way, two-way closed pump go out oil end with execution unit's oil feed end pass through second working oil way and link to each other.

2. A hydraulic control system for an injection molding machine as claimed in claim 1, wherein said first working fluid passage and said second working fluid passage are respectively provided with a pressure sensor, and said pressure sensors are electrically connected to said servo driver.

3. The hydraulic control system for an injection molding machine according to claim 1 or 2, further comprising an oil supply unit, the oil supply unit including an oil supply valve group and an oil supply power group, the oil supply power group including an oil supply pump and a three-phase asynchronous motor for driving the oil supply pump, the oil supply valve group including a first overflow valve, a second overflow valve, a third overflow valve, a flushing valve, a first check valve and a second check valve;

two oil inlet ends of the flushing valve are respectively connected with the first working oil way and the second working oil way, an oil outlet end of the flushing valve is connected with an oil inlet end of the first overflow valve, and an oil return end of the first overflow valve is connected with the oil tank;

the oil inlet end of the second overflow valve is connected with the first working oil way, the oil inlet end of the third overflow valve is connected with the second working oil way, the oil return end of the second overflow valve is connected with the second working oil way, the oil return end of the third overflow valve is connected with the first working oil way, the oil outlet end of the first check valve is connected with the first working oil way, the oil outlet end of the second check valve is connected with the second working oil way, a common oil way formed by connecting the oil inlet ends of the first check valve and the second check valve is connected with the oil outlet end of the oil supplementing pump, and the oil inlet end of the oil supplementing pump is connected with the oil tank;

the oil tank is characterized in that a common oil path formed by connecting the oil inlet ends of the first one-way valve and the second one-way valve is connected with the oil tank through the fourth overflow valve, a common oil path formed by connecting the oil inlet ends of the first one-way valve and the second one-way valve is connected with the oil inlet end of the fourth overflow valve, and the oil return end of the fourth overflow valve is connected with the oil tank.

4. A hydraulic control system as defined in claim 3, wherein an oil suction filter is disposed between an oil inlet of said oil replenishment pump and said oil tank, a first port of said oil suction filter is connected to said oil tank, and a second port of said oil suction filter is connected to an oil inlet of said oil replenishment pump.

5. The hydraulic control system of claim 4, wherein the oil outlet of the oil supply pump is provided with a high pressure filter, a first port of the high pressure filter is connected to the oil outlet of the oil supply pump, and a common oil path formed by connecting the oil inlet of the fourth relief valve, the oil inlet of the first check valve and the oil inlet of the second check valve is connected to a second port of the high pressure filter.

6. A hydraulic control system for an injection molding machine as claimed in claim 3, wherein the oil return ends of said first spill valve and said fourth spill valve are connected to said tank through a cooler, the oil return ends of said first spill valve and said fourth spill valve are connected to a first port of said cooler, respectively, and a second port of said cooler is connected to said tank.

7. A hydraulic control system for an injection molding machine as claimed in claim 3 wherein a drain port of said double closed pump is connected to said oil tank.

8. A hydraulic control system for an injection molding machine as claimed in claim 1 wherein said actuator unit is a double out rod cylinder of equal area.

9. A hydraulic control system for an injection molding machine as claimed in claim 1 wherein said actuator unit is a bi-directional rotary hydraulic motor.

10. A hydraulic control system for an injection molding machine as claimed in claim 9, wherein a drain port of said reversible hydraulic motor is connected to said oil tank.

Technical Field

The invention relates to a hydraulic system, in particular to a hydraulic control system for an injection molding machine.

Background

The hydraulic control system of an injection molding machine is an important component of the injection molding machine, such as the application of injection, sol-gel, mold opening and closing and ejection control of the injection molding machine, and conventionally adopts a form as shown in fig. 1, and mainly comprises an energy unit a1, a control and regulation unit a2, an execution unit A3, an auxiliary unit and a working medium. The energy unit A1 is composed of a servo driver A10, a servo motor A9 and a fixed displacement pump A8, and is used for converting mechanical energy provided by the servo motor A9 into pressure energy of liquid; the control and regulation unit A2 mainly comprises various valves and is used for controlling and regulating the pressure, flow and direction of liquid; the execution unit a3 generally refers to a hydraulic cylinder or a hydraulic motor, and is used for converting pressure energy of liquid into mechanical energy to drive a load to do linear reciprocating motion or rotary motion; the auxiliary units generally comprise an oil tank A7, an oil filter A4, a cooler A5, a pressure sensor A11, a pressure gauge A6, a liquid level gauge A12, an oil pipe, a joint and the like; the working medium is generally a hydraulic oil, which is responsible for the transfer of energy in the hydraulic system.

The working principle of the hydraulic control system is as follows: the fixed displacement pump A8 is driven by the servo motor A9 to rotate, and then sucks oil from the oil tank A7. Oil liquid enters a fixed displacement pump A8 through an oil filter A4, then the oil liquid is output from a fixed displacement pump A8 and enters a pipeline to reach a reversing valve A13, the left end or the right end of the reversing valve A13 is switched after being electrified, the oil liquid enters an execution device A3 through a port B or a port C, and the execution device A3 is driven to do linear reciprocating motion or rotary motion.

Due to the existence of the control and adjustment unit 2, the hydraulic control system is generally complex in oil circuit design, and the more complex the oil circuit is, the larger the pressure loss is, so that the efficiency of the whole system is low, and the energy consumption is high. In addition, when the execution unit 3 starts running, because the constant delivery pump 8 and the reversing valve 13 are difficult to open synchronously, the existence of the time difference can cause starting impact. When the quantitative pump 8 and various valves are closed and the execution unit 3 stops, the stop impact can be caused due to the existence of inertia, the execution unit 3 stops and is not positioned accurately, and when the reversing valve 13 in the control and adjustment unit 2 reverses to drive the execution unit 3 to move reversely, the impact is large during reversing due to the existence of inertia of the execution unit 3, and the impact is not well eliminated.

Disclosure of Invention

The invention aims to provide a precise, efficient and energy-saving hydraulic control system for an injection molding machine.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the utility model provides a hydraulic control system for injection molding machine, includes oil tank, energy unit and execution unit, the energy unit include servo driver, servo motor and two-way closed pump, the oil tank gives two-way closed pump mend oil, servo motor by servo driver drive, two-way closed pump by servo motor drive, two-way closed pump the oil feed end with execution unit's oil return end link to each other through first working oil circuit, two-way closed pump the oil output end with execution unit's oil feed end pass through second working oil circuit and link to each other.

And the first working oil path and the second working oil path are respectively provided with a pressure sensor, and the pressure sensors are in electric signal connection with the servo driver. The two pressure sensors are used for respectively collecting oil pressure of the first working oil way and oil pressure of the second working oil way, the collected oil pressure is fed back to the servo driver, the servo motor feeds back current rotating speed information to the servo driver through the encoder, the servo driver feeds back received information to the controller on the injection molding machine, the received information is compared with a set value in the controller, the output value of the servo driver for the servo motor is correspondingly adjusted, dynamic control of the rotating speed of the servo motor is achieved, and accurate closed-loop control of pressure and flow is achieved.

The oil supplementing unit comprises an oil supplementing valve group and an oil supplementing power group, the oil supplementing power group comprises an oil supplementing pump and a three-phase asynchronous motor for driving the oil supplementing pump, and the oil supplementing valve group comprises a first overflow valve, a second overflow valve, a third overflow valve, a flushing valve, a first check valve and a second check valve;

two oil inlet ends of the flushing valve are respectively connected with the first working oil way and the second working oil way, an oil outlet end of the flushing valve is connected with an oil inlet end of the first overflow valve, and an oil return end of the first overflow valve is connected with the oil tank;

the oil inlet end of the second overflow valve is connected with the first working oil way, the oil inlet end of the third overflow valve is connected with the second working oil way, the oil return end of the second overflow valve is connected with the second working oil way, the oil return end of the third overflow valve is connected with the first working oil way, the oil outlet end of the first check valve is connected with the first working oil way, the oil outlet end of the second check valve is connected with the second working oil way, a common oil way formed by connecting the oil inlet ends of the first check valve and the second check valve is connected with the oil outlet end of the oil supplementing pump, and the oil inlet end of the oil supplementing pump is connected with the oil tank;

the oil tank is characterized in that a common oil path formed by connecting the oil inlet ends of the first one-way valve and the second one-way valve is connected with the oil tank through the fourth overflow valve, a common oil path formed by connecting the oil inlet ends of the first one-way valve and the second one-way valve is connected with the oil inlet end of the fourth overflow valve, and the oil return end of the fourth overflow valve is connected with the oil tank. Through the structure, the problems of oil leakage and oil heating of the whole hydraulic system in the working process can be effectively solved, and the stable operation of the whole hydraulic system is ensured.

The oil supply system is characterized in that an oil absorption filter is arranged between the oil inlet end of the oil supply pump and the oil tank, a first port of the oil absorption filter is connected with the oil tank, and a second port of the oil absorption filter is connected with the oil inlet end of the oil supply pump. An oil absorption filter is arranged at the position, and residual pollutants in the oil tank can be filtered out through the oil absorption filter, so that the oil supplementing pump is protected.

The oil outlet end of the oil replenishing pump is provided with a high-pressure filter, a first port of the high-pressure filter is connected with the oil outlet end of the oil replenishing pump, and a common oil path formed by connecting the oil inlet end of the fourth overflow valve, the oil inlet end of the first one-way valve and the oil inlet end of the second one-way valve is respectively connected with a second port of the high-pressure filter. The high-pressure filter is arranged at the position, so that pollutants can be prevented from entering the whole hydraulic system through the high-pressure filter, the pollution concentration of the hydraulic system is effectively controlled, and important elements such as the bidirectional closed pump and the like are protected.

The oil return ends of the first overflow valve and the fourth overflow valve are connected with the oil tank through a cooler, the oil return ends of the first overflow valve and the fourth overflow valve are respectively connected with a first port of the cooler, and a second port of the cooler is connected with the oil tank. The cooler is used for cooling hot oil flushed back from the first working oil circuit or the second working oil circuit, the hot oil is cooled by the cooler to become cold oil, the cold oil enters the oil tank, and the cold oil is recycled, so that the heating condition of the whole system in operation is effectively controlled, and the stable and efficient operation of the whole system is ensured.

And an oil drainage port of the bidirectional closed pump is connected with the oil tank. The leaked hot oil can be cooled in the oil tank and recycled.

The flushing valve is a three-position three-way valve. Simple structure and convenient control.

The execution unit is an equal-area double-rod oil cylinder. The execution unit selects the double-rod oil cylinder with equal area, so that the oil inlet flow and the oil outlet flow are the same, and the circulating work of a closed system is realized.

The execution unit is a bidirectional rotating hydraulic motor. The execution unit selects a hydraulic motor, so that the oil inlet flow and the oil outlet flow are the same, and the circulating work of a closed system is realized.

And an oil drainage port of the bidirectional rotary hydraulic motor is connected with the oil tank. The leaked hot oil can be cooled in the oil tank and recycled.

Compared with the prior art, the invention has the advantages that: the bidirectional closed pump has a simple structure, the oil inlet end of the bidirectional closed pump is directly connected with the oil return end of the execution unit through the first working oil way, the oil outlet end of the bidirectional closed pump is directly connected with the oil inlet end of the execution unit through the second working oil way, and the positive and negative rotation of the bidirectional closed pump is controlled through the servo driver and the servo motor so as to drive the execution unit to do reciprocating or bidirectional rotary motion, so that a control and adjustment device in a conventional hydraulic system is omitted, and the problem of starting impact of the execution unit caused by asynchronous opening of a pump valve does not exist; secondly, the layout of the pipeline is simplified, so that the whole structure is compact and the space is saved; the servo motor drives the bidirectional closed pump to output hydraulic oil to drive the execution unit to move, the bidirectional closed pump is basically equivalent to a servo motor direct-drive execution unit, starting, braking and reversing of the execution unit are all controlled and adjusted through the servo driver and the servo motor, action response is quicker (about 80% higher than that of the traditional technology), position control is more accurate (about 80% higher than that of the traditional technology), hydraulic impact and energy loss caused by reversing and speed regulation of the traditional hydraulic system through a control adjusting device are avoided, and the bidirectional closed pump is more accurate, efficient and energy-saving; the injection molding machine can also be used in the occasions where multiple actions work synchronously in the injection molding machine, thereby effectively improving the production efficiency.

Drawings

FIG. 1 is a schematic diagram of a hydraulic system for mold opening and closing control of a conventional injection molding machine;

FIG. 2 is a schematic diagram of a first embodiment of the present invention;

fig. 3 is a schematic diagram of a second embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

The first embodiment is as follows: as shown in fig. 1, a hydraulic control system for injection molding machine, including oil tank 1, energy unit and execution unit 5, the energy unit includes servo driver 2, servo motor 3 and two-way closed pump 4, oil tank 1 mends oil for two-way closed pump 4, servo motor 3 is driven by servo driver 2, two-way closed pump 4 is driven by servo motor 3, the oil feed end of two-way closed pump 4 links to each other through first working oil way D with the oil return end of execution unit 5, the oil feed end of two-way closed pump 4 and the oil feed end of execution unit 5 link to each other through second working oil way E.

In this embodiment, a pressure sensor 6 is disposed on each of the first and second working oil paths D and E, and the pressure sensor 6 is electrically connected to the servo driver 2. The two pressure sensors 6 are used for respectively collecting oil pressure of the first working oil way D and oil pressure of the second working oil way E, the collected oil pressure is fed back to the servo driver 2, the servo motor 3 feeds back current rotating speed information to the servo driver 2 through the encoder, the servo driver 2 feeds back received information to a controller on the injection molding machine, the received information is compared with a value set in the controller, the output value of the servo driver 2 for the servo motor 3 is correspondingly adjusted, dynamic control of the rotating speed of the servo motor 3 is realized, and accurate closed-loop control of pressure and flow is realized.

In this specific embodiment, the system further comprises an oil supplementing unit, wherein the oil supplementing unit comprises an oil supplementing valve group and an oil supplementing power group, the oil supplementing power group comprises an oil supplementing pump 7 and a three-phase asynchronous motor 8 for driving the oil supplementing pump 7, and the oil supplementing valve group comprises a first overflow valve 9, a second overflow valve 10, a third overflow valve 11, a flushing valve 12, a first check valve 13 and a second check valve 14;

two oil inlet ends of the flushing valve 12 are respectively connected with the first working oil path D and the second working oil path E, an oil outlet end of the flushing valve 12 is connected with an oil inlet end of the first overflow valve 9, and an oil return end of the first overflow valve 9 is connected with the oil tank 1;

the oil inlet end of the second overflow valve 10 is connected with the first working oil path D, the oil inlet end of the third overflow valve 11 is connected with the second working oil path E, the oil return end of the second overflow valve 10 is connected with the second working oil path D, the oil return end of the third overflow valve 11 is connected with the first working oil path E, the oil outlet end of the first check valve 13 is connected with the first working oil path D, the oil outlet end of the second check valve is connected with the second working oil path E, a common oil path formed by connecting the oil inlet ends of the first check valve 13 and the second check valve 14 is connected with the oil outlet end of the oil supplementing pump 7, and the oil inlet end of the oil supplementing pump 7 is connected with the oil tank 1;

the common oil path formed by connecting the oil inlet ends of the first one-way valve 13 and the second one-way valve 14 is connected with the oil tank 1 through the fourth overflow valve 15, the common oil path formed by connecting the oil inlet ends of the first one-way valve 13 and the second one-way valve 14 is connected with the oil inlet end of the fourth overflow valve 15, and the oil return end of the fourth overflow valve 15 is connected with the oil tank 1. Through the structure, the problems of oil leakage and oil heating of the whole hydraulic system in the working process can be effectively solved, and the stable operation of the whole hydraulic system is ensured.

In this embodiment, an oil suction filter 16 is disposed between the oil inlet end of the oil replenishing pump 7 and the oil tank 1, a first port of the oil suction filter 16 is connected to the oil tank 1, and a second port of the oil suction filter 16 is connected to the oil inlet end of the oil replenishing pump 7. An oil suction filter 16 is provided at this position, and the oil suction filter 16 can filter out the pollutants remaining in the oil tank 1 to protect the oil replenishment pump 7.

In this embodiment, the oil outlet end of the oil replenishing pump 7 is provided with a high pressure filter 17, a first port of the high pressure filter 17 is connected to the oil outlet end of the oil replenishing pump 7, and a common oil path formed by connecting the oil inlet end of the fourth relief valve 15 and the oil inlet ends of the first check valve 13 and the second check valve 14 is connected to a second port of the high pressure filter 17, respectively. The high-pressure filter 17 is arranged at the position, pollutants can be prevented from entering the whole hydraulic system through the high-pressure filter 17, the pollution concentration of the hydraulic system is effectively controlled, and important elements such as the bidirectional closed pump 4 and the like are protected.

In this embodiment, the oil return ends of the first overflow valve 9 and the fourth overflow valve 15 are connected to the oil tank 1 through a cooler 18, the oil return ends of the first overflow valve 9 and the fourth overflow valve 15 are respectively connected to a first port of the cooler 18, and a second port of the cooler 18 is connected to the oil tank 1. The cooler 18 is used for cooling hot oil flushed back from the first working oil path D or the second working oil path E, and the hot oil is cooled by the cooler 18 to become cold oil and enters the oil tank 1 to be recycled, so that the heating condition of the whole system in operation is effectively controlled, and the whole system is ensured to operate stably and efficiently.

In this embodiment, the drain port of the two-way closed pump 4 is connected to the oil tank 1. The leaked hot oil can be cooled in the oil tank 1 and recycled.

In this embodiment, the flush valve 12 is a three-position, three-way valve. Simple structure and convenient control.

In this embodiment, the actuator unit 5 is an equal-area double-rod cylinder. The execution unit 5 adopts the double-rod oil cylinder with equal area, so that the oil inlet flow and the oil outlet flow are the same, and the circulating work of a closed system is realized.

Wherein, the servo motor 3 drives the bidirectional closed pump 4 to respectively work in a positive direction and a reverse direction to control oil pressure and flow; the bidirectional closed pump 4 can rotate in the forward direction and the reverse direction and can work normally; the two pressure sensors 6 are responsible for collecting oil pressure of the two working oil paths and feeding the oil pressure back to the servo driver 2; the first check valve 13 and the second check valve 14 are used for one-way oil passing, so that when oil is supplemented, the oil is prevented from being flushed back to the oil supplementing pump 7; the second overflow valve 10 and the third overflow valve 11 prevent the first working oil path D and the second working oil path E from being overloaded, limit the highest pressure during working, the first overflow valve 9 mainly plays a role in maintaining the pressure of the oil supplementing pump, and the fourth overflow valve 15 plays a role in limiting the pressure of the oil supplementing pump 7; when the first working oil path D and the second working oil path E have pressure difference, the flushing valve 12 is opened by high pressure, the oil of the oil supplementing pump 7 is supplemented into the working oil path with lower oil pressure, and then the oil returns to the tank 1 through the flushing valve 12 and the first overflow valve 9, because the oil supplementing pump 7 is supplemented with the filtered cold oil and the flushed hot oil, the oil in the working oil path can be filtered and cooled in the circulating process; the oil supplementing pump 7 is a fixed displacement pump and is driven by a three-phase asynchronous motor 8; the cooler 18 is hot oil that cools the first working oil path D and the second working oil path E back; the oil tank 1 is used for supplying cold oil to the oil supplementing pump 7 and the bidirectional closed pump 4 and collecting hot oil returned from a working oil circuit.

The working principle is as follows: supposing that when the servo motor 3 drives the bidirectional closed pump 4 to rotate forwards, the first working oil path D is a high-pressure oil path, and the second working oil path E is a low-pressure oil path, the two pressure sensors 6 feed back current pressure information to the servo driver 2, the servo motor 3 feeds back current rotating speed information to the prefecture driver 2 through an encoder, the servo driver 2 feeds back the received information to a controller on an injection molding machine, the received information is compared with a value given in the controller, the output value of the servo driver 2 to the servo motor 3 is correspondingly adjusted, the servo motor 3 is dynamically controlled, and accurate closed-loop control of pressure and flow is realized; when an execution element needs to be reversed, the servo motor 3 drives the bidirectional closed pump 4 to rotate reversely, the first working oil path D is a low-pressure oil path, the second working oil path E is a high-pressure oil path, the two pressure sensors 6 feed back current pressure information to the servo driver 2, the servo motor 3 feeds back current rotating speed information to the servo driver 2 through an encoder, the servo driver 2 feeds back the received information to a controller on the injection molding machine, the received information is compared with a value given by the controller, the output value of the servo driver 2 to the servo motor 3 is correspondingly adjusted, the servo motor 3 is dynamically controlled, and accurate closed-loop control of pressure and flow is achieved.

After the energy unit and the oil supplementing unit are started, the two-way closed pump 4 directly drives the equal-area double-outlet-rod oil cylinder to work forwards or backwards, the first working oil way D and the second working oil way E generate pressure difference, the flushing valve 12 is opened by the oil pressure on the high-pressure side of the working oil way, oil of the oil supplementing pump 7 is filtered by the high-pressure filter 17 and then is supplemented into the low-pressure working oil way through the check valve connected with the low-pressure working oil way, and redundant oil flows back to the oil tank 1 through the flushing valve 12, the first overflow valve 9 and the cooler 18. The surplus oil supplied through the oil replenishment unit is returned to the oil tank 1 through the fourth spill valve 15 and the cooler 18. When the first working oil path D or the second working oil path E has overpressure, the oil pressure at the overpressure side can open the second overflow valve 10 or the third overflow valve 11, and the overflowed oil flows into the low-pressure side, so that the system is prevented from being overloaded.

Example two: as shown in fig. 2, the other parts are the same as the first embodiment, except that the actuator unit 5 is a bidirectional rotary hydraulic motor. The execution unit 5 adopts a hydraulic motor, realizes that the oil inlet flow is the same as the oil outlet flow, and realizes the cycle work of a closed system.

In this embodiment, the drain port of the two-way rotary hydraulic motor is connected to the oil tank 1. The leaked hot oil can be cooled in the oil tank 1 and recycled.

After the energy unit and the oil supplementing unit are started, the bidirectional closed pump 4 directly drives the bidirectional rotary hydraulic motor to rotate forwards or reversely, the first working oil way D and the second working oil way E generate pressure difference, the flushing valve 12 is opened by the oil pressure on the high-pressure side of the working oil way, the oil of the oil supplementing pump 7 is filtered by the high-pressure filter 17 and then is supplemented into the low-pressure working oil way through the check valve connected with the low-pressure working oil way, and the redundant oil flows back to the oil tank 1 through the flushing valve 12, the first overflow valve 9 and the cooler 18. The surplus oil supplied through the oil replenishment unit is returned to the oil tank 1 through the fourth spill valve 15 and the cooler 18. When the first working oil path D or the second working oil path E has overpressure, the oil pressure at the overpressure side can open the second overflow valve 10 or the third overflow valve 11, and the overflowed oil flows into the low-pressure side, so that the system is prevented from being overloaded.