CN212384288U - High-low voltage switching control loop of servo control system - Google Patents
High-low voltage switching control loop of servo control system Download PDFInfo
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- CN212384288U CN212384288U CN202020309149.9U CN202020309149U CN212384288U CN 212384288 U CN212384288 U CN 212384288U CN 202020309149 U CN202020309149 U CN 202020309149U CN 212384288 U CN212384288 U CN 212384288U
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Abstract
A high-low pressure switching control loop of a servo control system comprises a first reversing valve, an oil inlet pipeline, a first oil outlet pipeline, a second oil outlet pipeline and a third oil outlet pipeline, wherein two ends of the first reversing valve are respectively connected with a power source and an oil inlet of the first reversing valve; the first reversing valve responds to the oil pressure of the first oil outlet pipeline and switches the conduction state of the oil inlet and the first working port and the conduction state of the oil inlet and the second working port. The utility model discloses a servo control system high-low pressure switches control circuit, and is more energy-conserving, can reduce hydraulic system calorific capacity.
Description
Technical Field
The utility model belongs to the technical field of the hydraulic system technique of rolling mill and specifically relates to a servo control system high-low pressure switches control circuit is related to.
Background
At present, a hydraulic servo system plays an important role in the field of automation, and particularly, most of systems requiring high power, high speed and accurate response adopt hydraulic control, such as a hydraulic thickness automatic control system widely used on a rolling mill. The hydraulic automatic thickness control system is a hydraulic AGC system or an HAGC system for short, and controls the displacement of a hydraulic cylinder through an electro-hydraulic servo valve so that a roller moves up and down to complete the control of a roller gap, thereby realizing the control of the thickness of a plate. The hydraulic automatic thickness control system is an important technology capable of improving the control precision of the plate and the yield of the product, and has become a new development direction of the thickness control system of the rolling mill due to the advantages of high precision, small inertia, high response speed, simple, convenient and flexible operation, safety, reliability and the like.
Due to the complexity of the process flow of the rolling mill, the hydraulic station of the rolling mill carries dozens of loads, even hundreds of loads, and correspondingly, the number of actuating mechanisms of the hydraulic automatic thickness control system is large. The pressure values required by the actuating mechanism of the hydraulic automatic thickness control system during action are not equal, so that an oil inlet pipeline of a hydraulic station of a rolling mill is often required to be connected with a plurality of oil outlet pipelines with different pressures, for example, a first oil outlet pipeline used for being connected with an actuating element for adjusting a roll gap, a second oil outlet pipeline used for being connected with the actuating element for adjusting the position of a roll and a third oil outlet pipeline used for being connected with the actuating element needing quick action, the set pressures of the first oil outlet pipeline, the second oil outlet pipeline and the third oil outlet pipeline are sequentially reduced, and pressure reducing valves are respectively arranged on the second oil outlet pipeline and the third oil outlet pipeline to maintain the set pressures of the second oil outlet pipeline and the third oil outlet pipeline. The device comprises an actuating element, a rolling mill hydraulic system and a control system, wherein the actuating element for adjusting a roll gap is an AGC (automatic gain control) pressing oil cylinder; the executing elements for adjusting the roller position mainly comprise a side-push oil cylinder, a middle roller transverse-moving oil cylinder, a supporting roller balancing oil cylinder, a middle roller bending oil cylinder and the like; the executing elements needing to be quickly operated mainly comprise an AGC (automatic gain control) pressing oil cylinder quick-operation, an AGC oil cylinder back pressure, a rolling line adjusting oil cylinder and the like.
Generally, each actuating element of a hydraulic system of a rolling mill needs a large flow when being started, and the requirement is smaller under normal working conditions. Because the hydraulic transmission system has certain internal leakage, in order to keep the pressure of the high-pressure hydraulic system of the rolling mill stable, under the normal working condition, the power source still runs in a state of high pressure and low flow, the oil inlet pipeline continuously supplies oil to each oil outlet pipeline, redundant hydraulic oil leaks through the oil drainage port of the pressure reducing valve, a large amount of power loss is caused, the energy conversion efficiency is low, the lost power is converted into heat, the temperature of the hydraulic transmission system is increased, and the service life of the hydraulic system is shortened.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that a high low pressure switching control circuit of servo control system is provided to foretell technical current situation, more energy-conserving and can reduce hydraulic system's calorific capacity.
The utility model provides a technical scheme that foretell technical problem adopted does: a high-low pressure switching control loop of a servo control system comprises an oil inlet pipeline, a first oil outlet pipeline, a second oil outlet pipeline and a third oil outlet pipeline, wherein the inlet of the oil inlet pipeline is connected with a power source, the outlet of the first oil outlet pipeline is used for being connected with an executing element for adjusting a roll gap, the outlet of the second oil outlet pipeline is used for being connected with an executing element for adjusting the position of a roll, and the outlet of the third oil outlet pipeline is used for being connected with an executing element needing to act quickly, and the high-low pressure switching control loop is characterized in that: the oil inlet of the first reversing valve is communicated with the outlet of the oil inlet pipeline, the first working port of the first reversing valve is communicated with the inlet of the first oil outlet pipeline, one path of the second working port of the first reversing valve is communicated with the inlet of the second oil outlet pipeline, and the other path of the second working port of the first reversing valve is communicated with the inlet of the third oil outlet pipeline; the oil pressure of the first oil outlet pipeline is lower than the first reversing pressure, the oil inlet of the first reversing valve is communicated with the first working port, and the oil inlet of the first reversing valve is communicated with the second working port when the oil pressure of the first oil outlet pipeline reaches the first reversing pressure.
When the oil pressure of the first oil outlet pipeline is lower than the first reversing pressure, the power source only supplies oil to the first oil outlet pipeline; when the oil pressure of the first oil outlet pipeline reaches a first reversing pressure, the power source stops supplying oil to the first oil outlet pipeline, and supplies oil to the second oil outlet pipeline and the third oil outlet pipeline; when the oil pressure of the first oil outlet pipeline is reduced to be lower than the first reversing pressure due to the internal leakage of the system, the power source stops supplying oil to the second oil outlet pipeline and the third oil outlet pipeline, and supplies oil to the first oil outlet pipeline again. The first reversing valve responds to the oil pressure of the first oil outlet pipeline to switch the oil supply state of the power source to each oil outlet pipeline, so that the power source only needs to supply oil to part of the oil outlet pipelines in normal working conditions, oil supply to all the oil outlet pipelines is not needed, the flow demand of the oil outlet pipelines on the power source can be reduced, the energy consumption of a hydraulic system is reduced, the heat productivity of the hydraulic transmission system can be reduced, and the service life of the hydraulic system is prolonged.
In order to control the reversing of the first reversing valve conveniently, the hydraulic reversing valve further comprises an oil unloading pipeline and a first sequence valve used for controlling the first reversing valve to change the flowing state of hydraulic oil in the first reversing valve, the first sequence valve is provided with an oil inlet and an oil outlet, the oil inlet of the first sequence valve is communicated with the first oil outlet pipeline, and the opening pressure of the first sequence valve is the first reversing pressure; the first reversing valve is a first hydraulic reversing valve with a control port, one path of the control port of the first hydraulic reversing valve is communicated with an oil outlet of the first sequence valve, and the other path of the control port of the first hydraulic reversing valve is communicated with the oil unloading pipeline. The first sequence valve responds to the oil pressure of the first oil outlet pipeline to control the first reversing valve to change the flowing direction of oil in the first reversing valve, and compared with an electromagnetic reversing valve which needs to be used in combination with a control element, the automatic control can be realized, the control is not needed to be controlled by an external controller, the control signal transmission is more reliable, and the operation is not easy to make mistakes.
The oil-feeding device is characterized by further comprising an oil return pipeline as a specific design of a power source, wherein the power source is a duplex pump driven by a servo motor, the duplex pump comprises a first quantitative pump and a second quantitative pump which are coaxially arranged, an oil outlet of the first quantitative pump is communicated with an inlet of the oil feeding pipeline, and an oil outlet of the second quantitative pump is communicated with the oil feeding pipeline through a pipeline; the branch pipeline is provided with a second reversing valve with an oil inlet, a first working opening and an oil return opening, the oil inlet of the second reversing valve is communicated with the oil outlet of the second constant displacement pump, the first working opening of the second reversing valve is communicated with the oil inlet pipeline, the oil return opening of the second reversing valve is communicated with the oil return pipeline, the oil pressure of the oil inlet pipeline is lower than the second reversing pressure, the oil inlet and the first working opening of the second reversing valve are communicated, the oil pressure of the oil inlet pipeline reaches the second reversing pressure, and the oil inlet and the oil return opening of the second reversing valve are communicated.
The double pump driven by the servo motor is used as a power source of a hydraulic system of the rolling mill, the first constant delivery pump and the second constant delivery pump are combined to supply oil when an execution element is started, and the servo motor runs at a high rotating speed to meet the requirement of large flow when the execution element is started; under the normal working condition, the second reversing valve responds to the oil pressure of the oil inlet pipeline to reverse, so that the second constant delivery pump is unloaded, only the first constant delivery pump supplies oil, and the servo motor runs at a low rotating speed to meet the small flow required by the normal running of the execution element; when the oil pressure of the oil inlet pipeline is reduced due to the working conditions such as large-flow action of the executing element, the first constant delivery pump and the second constant delivery pump are combined again for oil supply, the power source can supply oil more accurately according to actual requirements, power loss is further reduced, energy conversion efficiency is improved, the heat productivity of the hydraulic system can be further reduced, and the service life of the hydraulic system is prolonged.
In order to control the reversing of the second reversing valve conveniently, the hydraulic oil reversing valve further comprises a second sequence valve used for controlling the second reversing valve to change the flowing state of hydraulic oil in the second reversing valve, the second sequence valve is provided with an oil inlet and an oil outlet, the oil inlet of the second sequence valve is communicated with the oil inlet pipeline, and the opening pressure of the second sequence valve is the second reversing pressure; the second reversing valve is a second hydraulic reversing valve with a control port, one path of the control port of the second hydraulic reversing valve is communicated with the oil outlet of the second sequence valve, and the other path of the control port of the second hydraulic reversing valve is communicated with the oil unloading pipeline. Similarly, the second sequence valve realizes the self-control of the reversing of the second reversing valve, so that the control signal transmission is more reliable, and the operation is not easy to make mistakes.
In order to delay the resetting actions of the first hydraulic reversing valve and the second hydraulic reversing valve, a first damper used for adjusting the resetting time of the first hydraulic reversing valve is arranged between a control port of the first hydraulic reversing valve and the oil unloading pipeline; and a second damper used for adjusting the reset time of the second hydraulic directional control valve is arranged between the control port of the second hydraulic directional control valve and the oil unloading pipeline. The first damper and the second damper are arranged to respectively protect the first hydraulic reversing valve and the second hydraulic reversing valve.
In a hydraulic station of a rolling mill, the difference value between the large flow required when an actuating element is started and the small flow required when the actuating element is in a normal working condition is not large, so that the first fixed displacement pump is a large-flow low-pressure pump, and the second fixed displacement pump is a small-flow high-pressure pump in order to better adapt to the power requirement of the actuating element of a hydraulic system of the rolling mill. Under normal operating mode, this power supply still continues the fuel feeding through large-traffic low-pressure pump, makes the actuating element that the power supply can support move the more kind, and this power supply application scope is wider.
In order to accelerate unloading of the second fixed displacement pump, the second reversing valve is also provided with a second working port communicated with the oil return pipeline, and an oil inlet of the second reversing valve is also communicated with the second working port under the condition that the oil pressure of the oil inlet pipeline reaches a second reversing pressure; and a first one-way valve is arranged between a second working port of the second reversing valve and the oil return pipeline, an inlet of the first one-way valve is communicated with the second working port of the second reversing valve, and an outlet of the first one-way valve is communicated with the oil return pipeline. And when the oil pressure of the oil inlet pipeline reaches a set pressure, the hydraulic oil flowing out of the oil outlet of the second fixed displacement pump is unloaded simultaneously through the second working port and the oil return port of the second reversing valve, so that the unloading is quicker.
In order to protect the control loop, the oil-saving control system further comprises a first overflow valve and a second overflow valve, wherein the first overflow valve and the second overflow valve are both provided with an oil inlet and an oil outlet, the oil inlet of the first overflow valve is communicated with the oil inlet pipeline, and the oil outlet of the first overflow valve is communicated with the oil return pipeline; an oil inlet of the second overflow valve is communicated with the branch pipeline, and an oil outlet of the second overflow valve is communicated with the oil return pipeline.
In order to enable hydraulic oil in the first oil outlet pipeline, the second oil outlet pipeline and the third oil outlet pipeline to quickly enter into corresponding actuating elements, a second one-way valve, a third one-way valve and a fourth one-way valve are respectively arranged on the first oil outlet pipeline, the second oil outlet pipeline and the third oil outlet pipeline, an inlet of the second one-way valve is communicated with a first working port of the first reversing valve, and an outlet of the second one-way valve is used for being connected with the actuating element for adjusting the roll gap; and inlets of the third one-way valve and the fourth one-way valve are communicated with a second working port of the first reversing valve, an outlet of the third one-way valve is used for being connected with an executing element for adjusting the position of the roller, and an outlet of the fourth one-way valve is used for being communicated with the executing element needing to act quickly.
In order to remove impurities in the hydraulic oil, a high-pressure oil filter is arranged on the oil inlet pipeline.
Compared with the prior art, the utility model has the advantages of: the first reversing valve responds to the oil pressure of the first oil outlet pipeline to switch the oil supply state of the power source to each oil outlet pipeline, so that the power source only needs to supply oil to part of the oil outlet pipelines in normal working conditions, and does not need to supply oil to all the oil outlet pipelines, the flow demand of the oil outlet pipelines on the power source can be reduced, the energy consumption of a hydraulic system is reduced, the heat productivity of the hydraulic transmission system can be reduced, and the service life of the hydraulic system is prolonged; the double pump driven by the servo motor is used as a power source of a hydraulic transmission system of the rolling mill, when an execution element is started, the first constant delivery pump and the second constant delivery pump are combined to supply oil, the second constant delivery pump is unloaded under a normal working condition, only the first constant delivery pump supplies oil, oil can be supplied more accurately according to actual requirements, power loss is reduced, energy conversion efficiency is further improved, heat productivity of the hydraulic system is further reduced, and the service life of the hydraulic system is prolonged; the first sequence valve and the second sequence valve are used for respectively controlling the first hydraulic reversing valve and the second hydraulic reversing valve to switch the flowing direction of oil in the first hydraulic reversing valve and the second hydraulic reversing valve, and compared with an electromagnetic reversing valve which needs to be used in combination with a control element, the automatic control can be realized, the control is not needed to be controlled by an external controller, the control signal transmission is more reliable, and the operation is not easy to make mistakes; because the difference value of the flow needed by the actuating element of the rolling mill when starting and under the normal working condition is not large, the large-flow low-pressure pump is still used for continuously supplying oil under the normal working condition, the small-flow low-pressure pump is unloaded, the actual requirements of the actuating element of the rolling mill on the power source can be more met, the types of actions of the actuating element which can be supported by the power source are more, and the power source has wider application range.
Drawings
Fig. 1 is a schematic connection diagram of a high-low voltage switching control loop of the servo control system in the embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
As shown in fig. 1, the high-low pressure switching control circuit of the servo control system according to the present embodiment includes a dual pump, a servo motor 2, an oil inlet pipeline 31, a first oil outlet pipeline 32, a second oil outlet pipeline 33, a third oil outlet pipeline 34, an oil discharge pipeline 35, a branch pipeline 36, an oil return pipeline 37, a first directional valve 41, a second directional valve 42, a first sequence valve 51, a second sequence valve 52, a first damper 61, a second damper 62, a first check valve 71, a second check valve 72, a third check valve 73, a fourth check valve 74, a fifth check valve 75, a first overflow valve 81, a second overflow valve 82, and a high-pressure oil filter 9.
As shown in fig. 1, an inlet of the oil feed line 31 is connected to a power source. The outlet of the first oil outlet pipeline 32 is used for being connected with an actuator for adjusting the roll gap, the outlet of the second oil outlet pipeline 33 is used for being connected with an actuator for adjusting the position of the roll, and the outlet of the third oil outlet pipeline 34 is used for being connected with an actuator needing quick action. The first direction valve 41 has an oil inlet, a first working port and a second working port, the oil inlet of the first direction valve 41 is communicated with the outlet of the oil inlet pipeline 31, the first working port of the first direction valve 41 is communicated with the inlet of the first oil outlet pipeline 32, one path of the second working port of the first direction valve 41 is communicated with the inlet of the second oil outlet pipeline 33, and the other path is communicated with the inlet of the third oil outlet pipeline 34. When the oil pressure of the first oil outlet pipeline 32 is lower than the first reversing pressure, the oil inlet of the first reversing valve 41 is communicated with the first working port; when the oil pressure of the first oil outlet line 32 reaches the first direction switching pressure, the oil inlet of the first direction valve 41 and the second working port are connected.
In an embodiment, when the oil pressure of the first oil outlet line 32 is lower than the first reversing pressure, the power source only supplies oil to the first oil outlet line 32; when the oil pressure of the first oil outlet pipeline 32 reaches the first reversing pressure, the power source stops supplying oil to the first oil outlet pipeline 32, and supplies oil to the second oil outlet pipeline 33 and the third oil outlet pipeline 34; when the oil pressure of the first oil outlet line 32 decreases below the first reversing pressure due to system internal leakage, the power source stops supplying oil to the second oil outlet line 33 and the third oil outlet line 34, and supplies oil to the first oil outlet line 32 again. The first reversing valve 41 responds to the oil pressure of the first oil outlet pipeline 32 to switch the oil supply state of the power source to each oil outlet pipeline, so that the power source only needs to supply oil to part of the oil outlet pipelines and does not need to supply oil to all the oil outlet pipelines under the normal working condition, the flow demand of the oil outlet pipelines on the power source can be reduced, the energy consumption of a hydraulic system is reduced, the heat productivity of the hydraulic transmission system can be reduced, and the service life of the hydraulic system is prolonged.
Since the working pressure of the actuator for adjusting the roller position and the actuator requiring quick action are lower than the working pressure of the actuator for adjusting the roller gap, pressure reducing valves are respectively arranged between the second oil outlet pipeline 33 and the actuator for adjusting the roller position and between the third oil outlet pipeline 34 and the actuator requiring quick action to maintain the set pressure on the second oil outlet pipeline 33 and the third oil outlet pipeline 34. The arrangement of the pressure reducing valve is not separately shown in the figure, and it is possible to refer to the mounting structure of the pressure reducing valve on the second oil outlet line 33 and the third oil outlet line 34 in the prior art.
As shown in fig. 1, the first sequence valve 51 is used to control the first direction valve 41 to change the flow state of the hydraulic oil therein. The first sequence valve 51 is provided with an oil inlet and an oil outlet, the oil inlet of the first sequence valve 51 is communicated with the first oil outlet pipeline 32, and the opening pressure of the first sequence valve 51 is the first reversing pressure; the first directional control valve 41 is a first hydraulic directional control valve with a control port, one path of the control port of the first hydraulic directional control valve is communicated with the oil outlet of the first sequence valve 51, and the other path is communicated with the oil discharge pipeline 35. The first sequence valve 51 responds to the oil pressure of the first oil outlet pipeline 32 to control the first reversing valve 41 to change the flowing direction of the oil in the first reversing valve, and compared with an electromagnetic reversing valve which needs to be used in combination with a control element, the automatic control can be realized, the control is not needed to be controlled by an external controller, the control signal transmission is more reliable, and the operation is not easy to make mistakes.
As shown in fig. 1, in order to make the hydraulic oil in the first oil outlet pipeline 32, the second oil outlet pipeline 33 and the third oil outlet pipeline 34 quickly enter the corresponding actuator, a second check valve 72, a third check valve 73 and a fourth check valve 74 are respectively arranged on the first oil outlet pipeline 32, the second oil outlet pipeline 33 and the third oil outlet pipeline 34. Wherein, the inlet of the second check valve 72 is communicated with the first working port of the first reversing valve 41, and the outlet of the second check valve 72 is used for connecting with an actuator for adjusting the roll gap. The inlets of the third one-way valve 73 and the fourth one-way valve 74 are communicated with the second working port of the first reversing valve 41, the outlet of the third one-way valve 73 is used for being connected with an actuating element for adjusting the position of the roller, and the outlet of the fourth one-way valve 74 is used for being communicated with an actuating element needing quick action.
As shown in fig. 1, the power source is a dual pump driven by a servo motor 2, the dual pump includes a first fixed displacement pump 11 and a second fixed displacement pump 12 coaxially arranged, an oil outlet of the first fixed displacement pump 11 is communicated with an inlet of an oil inlet pipeline 32, and an oil outlet of the second fixed displacement pump 12 is communicated with the oil inlet pipeline 32 through a branch pipeline 36. The branch pipeline 36 is provided with a second reversing valve 42 having an oil inlet, a first working port and an oil return port, the oil inlet of the second reversing valve 42 is communicated with the oil outlet of the second fixed displacement pump 12, the first working port of the second reversing valve 42 is communicated with the oil inlet pipeline 32, and the oil return port of the second reversing valve 42 is communicated with the oil return pipeline 37. When the oil pressure of the oil inlet pipeline 32 is lower than the second reversing pressure, the oil inlet and the first working port of the second reversing valve 42 are communicated, and when the oil pressure of the oil inlet pipeline 32 reaches the second reversing pressure, the oil inlet and the oil return port of the second reversing valve 42 are communicated.
In the embodiment, the servo motor 2 is adopted to drive the dual pump to serve as a power source of a hydraulic system of the rolling mill, when an execution element is started, the first constant displacement pump 11 and the second constant displacement pump 12 are combined to supply oil, and the servo motor 2 runs at a high rotating speed to meet the requirement of large flow when the execution element is started; under normal working conditions, the second reversing valve 42 responds to the oil pressure of the oil inlet pipeline 32 to reverse, so that the second fixed displacement pump 12 is unloaded, only the first fixed displacement pump 11 supplies oil, and the servo motor 2 runs at a low rotating speed to meet the small flow required by the normal running of the executing element; when the oil pressure of the oil inlet pipeline 32 is reduced due to the working conditions of large-flow action and the like of the executing element, the first constant delivery pump 11 and the second constant delivery pump 12 are converged again for oil supply, the power source can supply oil more accurately according to actual requirements, power loss is further reduced, energy conversion efficiency is improved, the heat productivity of the hydraulic system can be further reduced, and the service life of the hydraulic system is prolonged.
As shown in fig. 1, the second sequence valve 52 is used to control the second direction valve 42 to change the flow state of the hydraulic oil therein. The second sequence valve 52 has an oil inlet and an oil outlet, and the oil inlet of the second sequence valve 52 is communicated with the oil inlet line 31, and the opening pressure of the second sequence valve 52 is a second switching pressure. The second direction valve 42 is a second hydraulic direction valve with a control port, one path of the control port of the second hydraulic direction valve is communicated with the oil outlet of the second sequence valve 52, and the other path is communicated with the oil discharge pipeline 35. Likewise, the second sequence valve 52 realizes the self-control of the reversing of the second reversing valve 42, so that the control signal transmission is more reliable, and the operation is not easy to make mistakes.
As shown in fig. 1, in order to make the hydraulic oil flowing out of the second fixed displacement pump 12 quickly enter the oil inlet pipeline 31, a fifth check valve 75 is arranged on the branch pipeline 36, an inlet of the fifth check valve 75 is communicated with the first working port of the second direction valve 42, and an outlet of the fifth check valve 75 is communicated with the oil inlet pipeline 31.
As shown in fig. 1, in order to accelerate unloading of the second fixed displacement pump 12, the second direction valve 42 further has a second working port communicating with the oil return line 37, and the oil inlet of the second direction valve 42 is also communicated with the second working port in a state where the oil pressure of the oil inlet line 31 reaches a second direction pressure. A first check valve 71 is arranged between the second working port of the second direction changing valve 42 and the oil return pipeline 37, an inlet of the first check valve 71 is communicated with the second working port of the second direction changing valve 42, and an outlet of the first check valve 71 is communicated with the oil return pipeline 71. When the oil pressure of the oil inlet pipeline 31 reaches the set pressure, the hydraulic oil flowing out of the oil outlet of the second fixed displacement pump 12 is unloaded through the second working port and the oil return port of the second reversing valve 42 at the same time, and unloading is faster.
As shown in fig. 1, in order to delay the reset actions of the first hydraulic directional control valve and the second hydraulic directional control valve, a first damper 61 for adjusting the reset time of the first hydraulic directional control valve is arranged between the control port of the first hydraulic directional control valve and the oil unloading pipeline 35; a second damper 62 for adjusting the reset time of the second hydraulic directional control valve is arranged between the control port of the second hydraulic directional control valve and the oil discharge line 35. The first damper 61 and the second damper 62 are provided to protect the first hydraulic directional valve and the second hydraulic directional valve, respectively.
In a hydraulic station of a rolling mill, the difference value between the large flow required when an actuating element is started and the small flow required when the actuating element is in a normal working condition is not large, so that in order to better adapt to the power requirement of the actuating element of a hydraulic system of the rolling mill, the first fixed displacement pump 11 is a large-flow low-pressure pump, and the second fixed displacement pump 12 is a small-flow high-pressure pump. Under normal operating mode, this power supply still continues the fuel feeding through large-traffic low-pressure pump, makes the actuating element that the power supply can support move the more kind, and this power supply application scope is wider.
As shown in fig. 1, a first relief valve 81 and a second relief valve 82 are used to protect the control circuit. The first overflow valve 81 and the second overflow valve 82 both have an oil inlet and an oil outlet, the oil inlet of the first overflow valve 81 is communicated with the oil inlet pipeline 31, and the oil outlet of the first overflow valve 81 is communicated with the oil return pipeline 37; the oil inlet of the second overflow valve 82 is communicated with the branch pipeline 36, and the oil outlet of the second overflow valve 82 is communicated with the oil return pipeline 37.
As shown in fig. 1, in order to remove impurities in the hydraulic oil, a high-pressure oil filter 9 is provided on the oil feed line 31.
Claims (10)
1. A high-low pressure switching control loop of a servo control system comprises an oil inlet pipeline (31), a first oil outlet pipeline (32), a second oil outlet pipeline (33) and a third oil outlet pipeline (34), wherein an inlet of the oil inlet pipeline (31) is connected with a power source, an outlet of the first oil outlet pipeline (32) is used for being connected with an executing element for adjusting a roll gap, an outlet of the second oil outlet pipeline (33) is used for being connected with an executing element for adjusting the position of a roll, and an outlet of the third oil outlet pipeline (34) is used for being connected with an executing element needing to act quickly, and the high-low pressure switching control loop is characterized in that: the oil-saving control valve further comprises a first reversing valve (41) with an oil inlet, a first working port and a second working port, the oil inlet of the first reversing valve (41) is communicated with the outlet of the oil inlet pipeline (31), the first working port of the first reversing valve (41) is communicated with the inlet of the first oil outlet pipeline (32), one path of the second working port of the first reversing valve (41) is communicated with the inlet of the second oil outlet pipeline (33), and the other path of the second working port of the first reversing valve (41) is communicated with the inlet of the third oil outlet pipeline (34); the oil pressure of the first oil outlet pipeline (32) is lower than a first reversing pressure, the oil inlet of the first reversing valve (41) is communicated with the first working port, and the oil inlet of the first reversing valve (41) is communicated with the second working port when the oil pressure of the first oil outlet pipeline (32) reaches the first reversing pressure.
2. A servo control system high and low voltage switching control loop as claimed in claim 1, wherein: the hydraulic control system further comprises an oil unloading pipeline (35) and a first sequence valve (51) used for controlling the first reversing valve (41) to change the flowing state of hydraulic oil inside the first sequence valve (51), wherein the first sequence valve (51) is provided with an oil inlet and an oil outlet, the oil inlet of the first sequence valve (51) is communicated with the first oil outlet pipeline (32), and the opening pressure of the first sequence valve (51) is the first reversing pressure; the first reversing valve (41) is a first hydraulic reversing valve with a control port, one path of the control port of the first hydraulic reversing valve is communicated with an oil outlet of the first sequence valve (51), and the other path of the control port of the first hydraulic reversing valve is communicated with the oil discharging pipeline (35).
3. A servo control system high and low voltage switching control loop as claimed in claim 2, wherein: the oil-return device is characterized by further comprising an oil return pipeline (37), the power source is a duplex pump driven by the servo motor (2), the duplex pump comprises a first constant delivery pump (11) and a second constant delivery pump (12) which are coaxially arranged, an oil outlet of the first constant delivery pump (11) is communicated with an inlet of the oil inlet pipeline (31), and an oil outlet of the second constant delivery pump (12) is communicated with the oil inlet pipeline (31) through a distribution pipeline (36); be equipped with second switching-over valve (42) that have oil inlet, first working opening and oil return opening on branch pipeline (36), the oil inlet of second switching-over valve (42) with the oil-out intercommunication of second constant displacement pump (12), the first working opening of second switching-over valve (42) with oil feed pipeline (31) intercommunication, the oil return opening of second switching-over valve (42) with oil return pipeline (37) intercommunication, under the oil pressure of oil feed pipeline (31) was less than the state of second switching-over pressure, the oil inlet and the first working opening of second switching-over valve (42) switch on, under the oil pressure of oil feed pipeline (31) reached the state of second switching-over pressure, the oil inlet and the oil return opening of second switching-over valve (42) switch on.
4. A servo control system high and low voltage switching control loop as claimed in claim 3, wherein: the hydraulic control system further comprises a second sequence valve (52) used for controlling the second reversing valve (42) to change the flow state of hydraulic oil inside the second sequence valve, the second sequence valve (52) is provided with an oil inlet and an oil outlet, the oil inlet of the second sequence valve (52) is communicated with the oil inlet pipeline (31), and the opening pressure of the second sequence valve (52) is the second reversing pressure; the second reversing valve (42) is a second hydraulic reversing valve with a control port, one path of the control port of the second hydraulic reversing valve is communicated with an oil outlet of the second sequence valve (52), and the other path of the control port of the second hydraulic reversing valve is communicated with the oil discharging pipeline (35).
5. The high-low voltage switching control loop of the servo control system as claimed in claim 4, wherein: a first damper (61) for adjusting the reset time of the first hydraulic reversing valve is arranged between the control port of the first hydraulic reversing valve and the oil unloading pipeline (35); and a second damper (62) for adjusting the reset time of the second hydraulic directional control valve is arranged between the control port of the second hydraulic directional control valve and the oil unloading pipeline (35).
6. A servo control system high and low voltage switching control loop as claimed in claim 3, wherein: the first fixed displacement pump (11) is a high-flow low-pressure pump, and the second fixed displacement pump (12) is a low-flow high-pressure pump.
7. A servo control system high and low voltage switching control loop as claimed in claim 3, wherein: the second reversing valve (42) is also provided with a second working port communicated with the oil return pipeline (37), and an oil inlet of the second reversing valve (42) is communicated with the second working port under the condition that the oil pressure of the oil inlet pipeline (31) reaches a second reversing pressure; and a first one-way valve (71) is arranged between a second working port of the second reversing valve (42) and the oil return pipeline (37), an inlet of the first one-way valve (71) is communicated with the second working port of the second reversing valve (42), and an outlet of the first one-way valve (71) is communicated with the oil return pipeline (37).
8. A servo control system high and low voltage switching control loop as claimed in claim 3, wherein: the oil inlet of the first overflow valve (81) is communicated with the oil inlet pipeline (31), and the oil outlet of the first overflow valve (81) is communicated with the oil return pipeline (37); an oil inlet of the second overflow valve (82) is communicated with the branch pipeline (36), and an oil outlet of the second overflow valve (82) is communicated with the oil return pipeline (37).
9. A servo control system high and low voltage switching control loop according to any one of claims 1-8, wherein: a second one-way valve (72), a third one-way valve (73) and a fourth one-way valve (74) are respectively arranged on the first oil outlet pipeline (32), the second oil outlet pipeline (33) and the third oil outlet pipeline (34), an inlet of the second one-way valve (72) is communicated with a first working port of the first reversing valve (41), and an outlet of the second one-way valve (72) is used for being connected with an actuating element for adjusting the roll gap; and inlets of the third one-way valve (73) and the fourth one-way valve (74) are communicated with a second working port of the first reversing valve (41), an outlet of the third one-way valve (73) is used for being connected with an actuating element for adjusting the position of the roller, and an outlet of the fourth one-way valve (74) is used for being communicated with the actuating element needing quick action.
10. A servo control system high and low voltage switching control loop according to any one of claims 1-8, wherein: and a high-pressure oil filter (9) is arranged on the oil inlet pipeline (31).
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| CN113617855A (en) * | 2021-07-16 | 2021-11-09 | 太原科技大学 | Rolling mill control method and system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113617855A (en) * | 2021-07-16 | 2021-11-09 | 太原科技大学 | Rolling mill control method and system |
| CN113617855B (en) * | 2021-07-16 | 2023-02-17 | 太原科技大学 | Rolling mill control method and system |
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