CN218439975U - Closed hydraulic system of injection molding machine - Google Patents
Closed hydraulic system of injection molding machine Download PDFInfo
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- CN218439975U CN218439975U CN202221877582.8U CN202221877582U CN218439975U CN 218439975 U CN218439975 U CN 218439975U CN 202221877582 U CN202221877582 U CN 202221877582U CN 218439975 U CN218439975 U CN 218439975U
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Abstract
The utility model discloses a closed hydraulic system of an injection molding machine, which is characterized by comprising an oil tank, a control unit, an energy unit, an equal-area execution unit and a non-equal-area execution unit; the energy unit comprises a servo driver, a servo motor and a bidirectional closed pump; the control unit comprises a three-position four-way reversing valve, a two-position four-way reversing valve and a first one-way valve. The closed hydraulic system has the advantages that the control unit is composed of the three-position four-way reversing valve, the two-position four-way reversing valve and the first check valve, and sequential work of the equal-area execution unit and the unequal-area execution unit is realized through sequential switching of all valves in the control unit, so that the closed hydraulic system is suitable for occasions with various working devices, no additional hydraulic system is required, and the manufacturing cost is effectively reduced.
Description
Technical Field
The utility model relates to a hydraulic system especially relates to a closed hydraulic system of injection molding machine.
Background
A closed hydraulic system commonly used in an injection molding machine at present is generally shown in fig. 1, and mainly comprises an energy unit C1, an execution unit C2, an oil supplement unit C3, an auxiliary unit, and a working medium. The energy unit C1 generally consists of a servo driver C4, a servo motor C5 and a bidirectional closed pump C6, and functions to convert mechanical energy provided by the servo motor C5 into pressure energy of liquid; the execution unit C generally refers to an equal-area double-rod hydraulic cylinder or a hydraulic motor and is used for converting pressure energy of liquid into mechanical energy and driving a load to do linear reciprocating motion or rotary motion; the oil supplementing unit C3 is generally composed of a common motor C18, a constant delivery pump C17, a filter C16, oil supplementing one-way valves C8 and C14 and an overflow valve C15, and is used for supplementing leaked oil in the working process of the closed pump and dissipating heat of the oil in a closed system by matching with a flushing valve C10; the auxiliary unit generally comprises a pressure sensor C7, a tank C21, an oil suction filter C20, a cooler C19, a system relief valve C9, a system relief valve C13, a flush valve C10 and a relief valve C12, which respectively function as: the pressure sensor C7 is used for feeding back the oil pressure of a working oil path to a controller to realize the pressure closed-loop control of the whole hydraulic system, the oil tank C21 is used for storing oil required by the oil supplementing pump C17, recovering oil leaked by the closed pump C6 and recovering oil flushed back through the flushing valve C10, the oil absorption filter C20 is used for filtering the oil entering the oil supplementing pump C17, the cooler C19 is used for cooling the oil overflowing from the oil supplementing unit C3 and the oil flushed back by the flushing valve C10, the system overflow valve C9 is used for limiting the highest working pressure of the working oil path D to ensure the safety of the system, the system overflow valve C13 is used for limiting the highest working pressure of the working oil path E to ensure the safety of the system, the flushing valve C10 is switched by using the oil pressure at the high-pressure side of the working oil path to enable the oil at the low-pressure side to be flushed, the overflow valve C12 is used for limiting the oil return pressure of the flushing valve C10 to establish oil return back pressure to enable the hydraulic system to be kept stable; the working medium is generally a hydraulic oil, which is responsible for the transfer of energy in the hydraulic system.
The working device (execution unit) of the closed hydraulic system is generally an oil cylinder or a hydraulic motor with equal area, and the oil inlet flow and the oil return flow of the oil cylinder or the hydraulic motor with equal area are the same, so that the stable operation of a closed pump in the hydraulic system can be ensured. Based on this, the closed hydraulic system can only be applied to an injection molding machine with an open-close oil cylinder being an equal-area oil cylinder for controlling the open-close action, but other working devices (such as an injection moving oil cylinder, an ejection oil cylinder, a core pulling oil cylinder and the like) with unequal areas on the injection molding machine are difficult to modify into equal areas due to the limitation of space and position, that is, the closed hydraulic system is obviously not applicable to the injection molding machine with the working devices with equal areas and unequal areas, that is, a set of hydraulic system is required to be additionally arranged for the working devices with unequal areas, so that the integral manufacturing cost of the injection molding machine is higher.
Disclosure of Invention
The utility model aims to solve the technical problem that a closed hydraulic system who is suitable for the injection molding machine that has multiclass equipment to use is provided.
The utility model provides a technical scheme that above-mentioned technical problem adopted does:
a closed hydraulic system of an injection molding machine comprises an oil tank, a control unit, an energy unit, an equal-area execution unit and a non-equal-area execution unit;
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, and the bidirectional closed pump is driven by the servo motor; the control unit comprises a three-position four-way reversing valve, a two-position four-way reversing valve and a first one-way valve;
a first working oil port of the three-position four-way reversing valve is connected with an oil port of a large-area cavity of the unequal-area execution unit, and a second working oil port of the three-position four-way reversing valve is connected with an oil port of a small-area cavity of the unequal-area execution unit; a first working oil port and a second working oil port of the two-position four-way reversing valve are respectively connected with two oil ports of the equal-area execution unit; a common oil path formed by connecting an oil inlet of the three-position four-way reversing valve and an oil inlet of the two-position four-way reversing valve is connected with an oil outlet end of the two-way closed pump through a first working oil path, and a common oil path formed by connecting an oil outlet of the two-position four-way reversing valve and an oil outlet of the first one-way valve is connected with an oil inlet end of the two-way closed pump through a second working oil path; and the oil outlet of the three-position four-way reversing valve is connected with the oil inlet end of the first one-way valve to form a common end which is connected with the oil tank.
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 fourth overflow valve, a flushing valve and a second one-way 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 a common oil way formed by connecting an oil return end of the first overflow valve and an oil return end of the fourth 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, and the oil return end of the second overflow valve is connected with the second working oil way; the oil inlet end of the third overflow valve is connected with the second working oil way, and the oil return end of the third overflow valve is connected with the first working oil way; the oil outlet end of the second one-way valve is connected with the first working oil way, the oil inlet end of the second one-way valve, the oil outlet of the two-position four-way reversing valve and the oil outlet of the first one-way valve are connected to form a common oil way, the common oil way is connected with the oil inlet end of the fourth overflow valve to form a common oil way, the common oil way 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. 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. When the oil inlet of the unequal area execution unit is less and the oil return is more, redundant oil return can overflow the oil return tank through an overflow valve in the oil supplementing unit, and when the oil inlet of the unequal area execution unit is more and the oil return is less, the insufficient oil absorption of the bidirectional closed pump can be supplemented through the oil supplementing unit; thereby ensuring normal operation of the unequal area execution unit.
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, a common oil path formed by connecting the oil outlet of the two-position four-way reversing valve and the oil outlet of the first one-way valve is connected with a common oil path formed by connecting the oil inlet end of the fourth overflow valve, and a second port of the high-pressure filter is connected. 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 from the first working oil path or the second working oil path, and the hot oil is cooled by the cooler to become cold oil and enters the oil tank 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.
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 unequal area execution unit is an unequal area oil cylinder. The specific selection can be carried out according to different working conditions.
The equal-area execution unit is an equal-area double-rod oil cylinder or a hydraulic motor. The specific selection can be carried out according to different working conditions.
Compared with the prior art, the utility model has the advantages of: the control unit consists of a three-position four-way reversing valve, a two-position four-way reversing valve and a first one-way valve, and the sequential work of an equal-area execution unit and a non-equal-area execution unit is realized through the sequential switching of all valves in the control unit; the oil inlet amount and the oil return amount of the unequal area execution unit are different, and the situation that oil inlet is less in oil return or oil inlet is more in oil return and less in oil return can be met during working, so that the action of the unequal area execution unit is reversed mainly through the reversing valve (the working direction of the bidirectional closed pump is kept unchanged in the process), the closed hydraulic system is suitable for occasions with various working devices, an additional hydraulic system is not required, and the manufacturing cost is effectively reduced.
Drawings
FIG. 1 is a schematic diagram of a closed hydraulic system for 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 present invention will be described in further detail with reference to the following embodiments.
The first embodiment is as follows: as shown in fig. 2, a closed hydraulic system of an injection molding machine comprises an oil tank 1, a control unit, an energy unit, an equal-area execution unit 2 and a non-equal-area execution unit 3;
the energy unit comprises a servo driver 4, a servo motor 5 and a bidirectional closed pump 6, the oil tank 1 supplies oil to the bidirectional closed pump 6, the servo motor 5 is driven by the servo driver 4, and the bidirectional closed pump 6 is driven by the servo motor 5; the control unit comprises a three-position four-way reversing valve 7, a two-position four-way reversing valve 8 and a first one-way valve 9;
a first working oil port A of the three-position four-way reversing valve 7 is connected with an oil port of a large-area cavity of the non-equal-area execution unit 3, and a second working oil port B of the three-position four-way reversing valve 7 is connected with an oil port of a small-area cavity of the non-equal-area execution unit 3; a first working oil port A and a second working oil port B of the two-position four-way reversing valve 8 are respectively connected with two oil ports of the equal-area execution unit 2; a common oil path formed by connecting an oil inlet P port of the three-position four-way reversing valve 7 and an oil inlet P port of the two-position four-way reversing valve 8 is connected with an oil outlet end of the two-way closed pump 6 through a first working oil path D, and a common oil path formed by connecting an oil outlet T port of the two-position four-way reversing valve 8 and an oil outlet of the first one-way valve 9 is connected with an oil inlet end of the two-way closed pump 6 through a second working oil path E; an oil outlet T port of the three-position four-way reversing valve 7 is connected with an oil inlet end of the first one-way valve 9 to form a common end which is connected with the oil tank 1.
In this embodiment, a pressure sensor 10 is disposed on each of the first working oil path D and the second working oil path E, and the pressure sensor 10 is electrically connected to the servo driver 4. The two pressure sensors 10 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 4, the servo motor 5 feeds back current rotating speed information to the servo driver 4 through the encoder, the servo driver 4 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 4 for the servo motor 5 is correspondingly adjusted, dynamic control of the rotating speed of the servo motor 5 is realized, and accurate closed-loop control of pressure and flow is realized.
In this embodiment, the drain port of the two-way closed pump 6 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 unequal area execution unit 3 is an unequal area cylinder. The specific selection can be carried out according to different working conditions.
In this embodiment, the equal-area execution unit 2 is an equal-area double-rod cylinder or a hydraulic motor. The specific selection can be carried out according to different working conditions.
Example two: as shown in fig. 3, the other parts are the same as those in the first embodiment, and the difference is that the oil supplementing unit further includes an oil supplementing valve group and an oil supplementing power group, the oil supplementing power group includes an oil supplementing pump 11 and a three-phase asynchronous motor 12 for driving the oil supplementing pump 11, and the oil supplementing valve group includes a first overflow valve 13, a second overflow valve 14, a third overflow valve 15, a fourth overflow valve 16, a flushing valve 17 and a second check valve 18;
two oil inlet ends of the flushing valve 17 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 17 is connected with an oil inlet end of the first overflow valve 13, and a common oil path formed by connecting an oil return end of the first overflow valve 13 and an oil return end of the fourth overflow valve 16 is connected with the oil tank 1; the oil inlet end of the second overflow valve 14 is connected with the first working oil path D, and the oil return end of the second overflow valve 14 is connected with the second working oil path E; the oil inlet end of the third overflow valve 15 is connected with the second working oil path E, and the oil return end of the third overflow valve 15 is connected with the first working oil path D; the oil outlet end of the second one-way valve 18 is connected with the first working oil path D, a common oil path formed by connecting the oil inlet end of the second one-way valve 18, the oil outlet T port of the two-position four-way reversing valve 8 and the oil outlet of the first one-way valve 9 is connected with the oil inlet end of the fourth overflow valve 16 to form a common oil path, the oil outlet end of the oil supplementing pump 11 is connected with the oil tank 1, and the oil inlet end of the oil supplementing pump 11 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. When the oil inlet of the unequal area execution unit 3 is less and the oil return is more, redundant oil return can overflow the oil return tank through an overflow valve in the oil supplementing unit, and when the oil inlet of the unequal area execution unit 3 is more and less, the insufficient oil absorption of the bidirectional closed pump 6 can be supplemented through the oil supplementing unit; thereby ensuring normal operation of the unequal area execution unit 3.
In this embodiment, an oil suction filter 19 is disposed between the oil inlet end of the oil replenishing pump 11 and the oil tank 1, a first port of the oil suction filter 19 is connected to the oil tank 1, and a second port of the oil suction filter 19 is connected to the oil inlet end of the oil replenishing pump 11. An oil suction filter 19 is provided at this position, and the contaminant remaining in the oil tank 1 can be filtered by the oil suction filter 19, thereby protecting the oil charge pump 11.
In this embodiment, the oil outlet end of the oil replenishing pump 11 is provided with a high pressure filter 20, a first port of the high pressure filter 20 is connected with the oil outlet end of the oil replenishing pump 11, and a common oil path formed by connecting the oil outlet T of the two-position four-way reversing valve 8 and the oil outlet of the first check valve 9 and the oil inlet end of the fourth overflow valve 16 is connected with a second port of the high pressure filter 20. The high-pressure filter 20 is arranged at the position, pollutants can be prevented from entering the whole hydraulic system through the high-pressure filter 20, the pollution concentration of the hydraulic system is effectively controlled, and important elements such as the bidirectional closed pump 6 and the like are protected.
In this embodiment, the oil return ends of the first overflow valve 13 and the fourth overflow valve 16 are connected to the oil tank 1 through a cooler 21, the oil return ends of the first overflow valve 13 and the fourth overflow valve 16 are respectively connected to a first port of the cooler 21, and a second port of the cooler 21 is connected to the oil tank 1. The cooler 21 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 21 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 flush valve 17 is a three-position, three-way valve. Simple structure and convenient control.
Wherein, the servo motor 5 drives the bidirectional closed pump 6 to respectively work in the forward direction and the reverse direction to control the oil pressure and the flow; the bidirectional closed pump 6 can rotate in the forward direction and the reverse direction and can work normally; the two double pressure sensors 10 are responsible for collecting oil pressures of the two working oil paths and feeding the oil pressures back to the servo driver 4; the first check valve 9 and the second check valve 18 play a role of one-way oil passing, so that when oil is supplemented, the oil is prevented from back flushing the oil supplementing pump 11; the second overflow valve 14 and the third overflow valve 15 are used for preventing the pressure of the first working oil path D and the second working oil path E from being overloaded, and limiting the highest pressure during working, the first overflow valve 13 mainly plays a role of limiting the oil return pressure of the flushing valve 17, establishing oil return back pressure to keep the hydraulic system stable, and the fourth overflow valve 15 plays a role of limiting the pressure of the oil supplementing pump 11; when the first working oil path D and the second working oil path E have pressure difference, the flushing valve 17 is opened by high pressure, the oil of the oil supplementing pump 11 is supplemented into the working oil path with lower oil pressure, and then the oil returns to the tank 1 through the flushing valve 17 and the first overflow valve 13, because the oil supplementing pump 11 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 replenishing pump 11 is a fixed displacement pump and is driven by a three-phase asynchronous motor 12; the cooler 21 is used for cooling hot oil flushed back from the first working oil path D or the second working oil path E, excess oil of the cooling oil supplementing pump 11 and oil returned by overflowing through the fourth overflow valve 16; the oil tank 1 is used for providing cold oil for the oil supplementing pump 11 and the bidirectional closed pump 6 and collecting hot oil returned by a working oil circuit; the three-position four-way reversing valve 7 is used for controlling the movement and the reversing of the unequal area execution unit 3, and the two-position four-way reversing valve 8 is used for controlling the movement of the equal area execution unit 2.
The specific working principle is as follows: when the equal-area execution unit 2 needs to work, the two-position four-way reversing valve 8 is electrically reversed, the port P of the two-position four-way reversing valve 8 is communicated with the port A, the port B is communicated with the port T, and if the servo motor 5 drives the bidirectional closed pump 6 to rotate forward, the first working oil way D is a high-pressure oil way, and the second working oil way E is a low-pressure oil way, the two double-pressure sensors 10 feed back current pressure information to the servo driver 4, the servo motor 5 feeds back current rotating speed information to the prefusion driver 2 through an encoder, the servo driver 4 feeds back received information to a controller on an injection molding machine, the received information is compared with a value given by the controller, the output value of the servo driver 4 to the servo motor 5 is correspondingly adjusted, the servo motor 5 is dynamically controlled, and accurate closed-loop control of pressure flow is realized; when an execution element needs to be reversed, the servo motor 5 drives the bidirectional closed pump 6 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 double-pressure sensors 10 feed back current pressure information to the servo driver 4, the servo motor 5 feeds back current rotating speed information to the servo driver 4 through the encoder, the servo driver 4 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 4 to the servo motor 5 is correspondingly adjusted, the servo motor 5 is dynamically controlled, and accurate closed-loop control over pressure and flow is achieved. After the equal-area execution unit 2 finishes acting, the two-position four-way valve 21 is powered off, the PTAB oil ports of the two-position four-way valve 21 are not communicated, and the two cavities of the equal-area execution unit 2 are sealed;
when the unequal area execution unit 3 needs to work, the port P of the three-position four-way reversing valve 7 needs to be kept in oil inlet all the time, and the port T always returns oil, namely in the whole working process of the unequal area execution unit 3, the two-way closed pump 6 only needs to keep one steering to enable the first working oil path D to always produce oil and enable the second working oil path E to always return oil, if the unequal area execution unit 3 needs to be reversed, the reversing is carried out through the three-position four-way reversing valve 7, and the reversing through the two-way closed pump 6 is not needed. When the left side of the three-position four-way reversing valve 7 is electrified, the port P of the three-position four-way reversing valve 7 is communicated with the port B, the port A is communicated with the port T, namely, the small cavity of the unequal-area execution unit 3 is fed with oil and returned by the large cavity, the oil return amount is larger than the oil inlet amount at the moment, redundant oil return can return to a cooler for cooling and then returns to an oil tank through the overflow valve 15, and the bidirectional closed pump 6 can stably operate to enable the unequal-area execution unit 3 to retreat; when the right side of the three-position four-way reversing valve 7 is electrified, the port P of the three-position four-way reversing valve 7 is communicated with the port A, and the port B is communicated with the port T, namely, the large cavity oil inlet small cavity oil return of the unequal-area execution unit 3 is realized, at the moment, the oil return amount is smaller than the oil inlet amount, the shortage of the oil return amount can be compensated by the oil supplementing pump 11, and the bidirectional closed pump 6 can stably operate to enable the unequal-area execution unit 3 to work forwards. In the whole working process of the unequal-area execution unit 3, the bidirectional closed pump 6 only needs to keep one steering direction to enable the first working oil path D to always produce oil, then only the double pressure sensors 10 connected to the first oil path D need to feed back current pressure information to the servo driver 4, the servo motor 5 feeds back current rotating speed information to the ground house driver 2 through the encoder, the servo driver 4 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 4 to the servo motor 5 is correspondingly adjusted, the servo motor 5 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 synchronously, the two-way closed pump 6 drives the execution unit to work, the first working oil path D and the second working oil path E generate pressure difference, the flushing valve 17 is opened by the oil pressure on the high-pressure side of the working oil paths, oil of the oil supplementing pump 11 is filtered by the high-pressure filter 17 and then is supplemented into the low-pressure working oil path through the one-way valve connected with the low-pressure working oil path, and redundant oil flows back to the oil tank 1 through the flushing valve 17, the first overflow valve 13 and the cooler 21. 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 21. When the first working oil path D or the second working oil path E is overpressurized, the oil pressure on the overpressurization side opens the second relief valve 14 or the third relief valve 15, and the overflowed oil flows into the low-pressure side, so that the system is prevented from being overloaded.
Claims (10)
1. A closed hydraulic system of an injection molding machine is characterized by comprising an oil tank, a control unit, an energy unit, an equal-area execution unit and a non-equal-area execution unit;
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, and the bidirectional closed pump is driven by the servo motor; the control unit comprises a three-position four-way reversing valve, a two-position four-way reversing valve and a first one-way valve;
the first working oil port of the three-position four-way reversing valve is connected with the oil port of the large-area cavity of the unequal-area execution unit, and the second working oil port of the three-position four-way reversing valve is connected with the oil port of the small-area cavity of the unequal-area execution unit; a first working oil port and a second working oil port of the two-position four-way reversing valve are respectively connected with two oil ports of the equal-area execution unit; a common oil path formed by connecting an oil inlet of the three-position four-way reversing valve and an oil inlet of the two-position four-way reversing valve is connected with an oil outlet end of the two-way closed pump through a first working oil path, and a common oil path formed by connecting an oil outlet of the two-position four-way reversing valve and an oil outlet of the first one-way valve is connected with an oil inlet end of the two-way closed pump through a second working oil path; and the common end formed by connecting the oil outlet of the three-position four-way reversing valve and the oil inlet end of the first one-way valve is connected with the oil tank.
2. The closed hydraulic system of an injection molding machine as claimed in claim 1, wherein a pressure sensor is provided on each of the first and second hydraulic fluid paths, and the pressure sensors are electrically connected to the servo driver.
3. The closed hydraulic system of an injection molding machine according to claim 1, further comprising an oil replenishment unit, the oil replenishment unit comprising an oil replenishment valve bank and an oil replenishment power bank, the oil replenishment power bank comprising an oil replenishment pump and a three-phase asynchronous motor for driving the oil replenishment pump, the oil replenishment valve bank comprising a first overflow valve, a second overflow valve, a third overflow valve, a fourth overflow valve, a flushing 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 a common oil way formed by connecting an oil return end of the first overflow valve and an oil return end of the fourth 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, and the oil return end of the second overflow valve is connected with the second working oil way; the oil inlet end of the third overflow valve is connected with the second working oil way, and the oil return end of the third overflow valve is connected with the first working oil way; the oil outlet end of the second one-way valve is connected with the first working oil way, the oil inlet end of the second one-way valve, the oil outlet of the two-position four-way reversing valve and the oil outlet of the first one-way valve are connected to form a common oil way, the common oil way is connected with the oil inlet end of the fourth overflow valve to form a common oil way, the common oil way 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.
4. The closed hydraulic system of an injection molding machine according to claim 3, wherein an oil suction filter is disposed between an oil inlet of the oil replenishment pump and the oil tank, a first port of the oil suction filter is connected to the oil tank, and a second port of the oil suction filter is connected to an oil inlet of the oil replenishment pump.
5. The closed hydraulic system of an injection molding machine according to claim 4, wherein the oil outlet end of the oil replenishment 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 replenishment pump, and a common oil path formed by connecting the oil outlet of the two-position four-way reversing valve and the oil outlet of the first check valve is connected with a second port of the high pressure filter.
6. The closed hydraulic system of an injection molding machine according to claim 3, wherein the oil return ends of the first overflow valve and the fourth overflow valve are connected to the oil tank through a cooler, the oil return ends of the first overflow valve and the fourth overflow valve are respectively connected to a first port of the cooler, and a second port of the cooler is connected to the oil tank.
7. The closed hydraulic system of an injection molding machine as claimed in claim 1, wherein the drain port of the two-way closed pump is connected to the oil tank.
8. A closed hydraulic system for an injection molding machine as claimed in claim 3 wherein said flush valve is a three-position, three-way valve.
9. The closed hydraulic system of an injection molding machine as defined in claim 1 wherein said unequal area actuating units are unequal area cylinders.
10. The closed hydraulic system of an injection molding machine as defined in claim 1 wherein said equal area actuating unit is an equal area dual ram cylinder or hydraulic motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221877582.8U CN218439975U (en) | 2022-07-20 | 2022-07-20 | Closed hydraulic system of injection molding machine |
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