CN111365310A - Hydraulic unloading system - Google Patents
Hydraulic unloading system Download PDFInfo
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- CN111365310A CN111365310A CN202010117492.8A CN202010117492A CN111365310A CN 111365310 A CN111365310 A CN 111365310A CN 202010117492 A CN202010117492 A CN 202010117492A CN 111365310 A CN111365310 A CN 111365310A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/003—Systems with load-holding valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
- F15B21/08—Servomotor systems incorporating electrically operated control means
- F15B21/087—Control strategy, e.g. with block diagram
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/40—Flow control
- F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
The invention discloses a hydraulic unloading system, which comprises a first pump body, a first reversing valve, a second reversing valve, a direct-push oil cylinder and a first pump body low-pressure overflow valve, wherein the first pump body is communicated with a hydraulic oil tank and the second reversing valve through a main pressure oil way, two oil outlets of the second reversing valve are respectively connected with two access ports of a buffer valve, two output ports of the buffer valve are respectively connected with a rod cavity and a rodless cavity of the direct-push oil cylinder, an oil return port of the second reversing valve is communicated with the hydraulic oil tank through an oil return pipeline, the first reversing valve is arranged between the first pump body and the second reversing valve, one end of the first pump body low-pressure overflow valve is connected to a pipeline between the first pump body and the first reversing valve, the other end of the first pump body low-pressure overflow valve is communicated with the oil return pipeline, and the direct-push oil cylinder is unloaded by high-pressure oil before the; the problem that the water hammer phenomenon of a hydraulic driving system of a direct-push oil cylinder in the prior art is serious can be solved.
Description
Technical Field
The invention relates to the technical field of hydraulic control, in particular to a hydraulic unloading system.
Background
The prior hydraulic drive system of the shovel cart has the following problems in use: firstly, because the volume of the direct-push oil cylinder is large, the extension and retraction of the direct-push oil cylinder is determined by sensing the oil pressure in a main pressure oil way, and the pressure is basically about 20MPa, therefore, when the direct-push oil cylinder performs the recovery action, a large amount of high-pressure oil seals are closed between the direct-push oil cylinder and a reversing valve, when a hydraulic system directly reverses, the high-pressure oil directly returns to an oil tank, so that the pipeline impact is large, the water hammer phenomenon is serious, and long-term impact easily causes the faults of loosening and oil leakage of a pipeline joint, shortening of the service life of a rubber pipe, damage of a sealing ring and the.
Secondly, the ground conditions of various places are different in practical use, so that the feeding hopper always has a certain movement stroke when descending to the ground, the driving speed of the lifting plate oil cylinder is high, the lifting plate oil cylinder cannot be stopped to an accurate position manually, the feeding hopper always can be jacked up and pulled forwards for a short distance by the descending stroke of the feeding hopper in the working cycle, and the feeding hopper can be pulled forwards for a long distance when being full, so that the feeding hopper has great working influence on places with limited space.
Therefore, a new hydraulic unloading system is urgently needed.
Disclosure of Invention
In view of the defects, the invention provides a hydraulic unloading system which can solve the problem of serious water hammer phenomenon of a hydraulic driving system of a direct-push oil cylinder in the prior art.
In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:
the hydraulic unloading system comprises a first pump body, a first reversing valve, a second reversing valve, a direct-push oil cylinder and a first pump body low-pressure overflow valve, wherein the first pump body is communicated with a hydraulic oil tank and the second reversing valve through a main pressure oil way, two oil outlets of the second reversing valve are respectively connected with two access ports of a buffer valve, two output ports of the buffer valve are respectively connected with a rod cavity and a rodless cavity of the direct-push oil cylinder, an oil return port of the second reversing valve is communicated with the hydraulic oil tank through an oil return pipeline, the first reversing valve is arranged between the first pump body and the second reversing valve, one end of the first pump body low-pressure overflow valve is connected onto a pipeline between the first pump body and the first reversing valve, the other end of the first pump body low-pressure overflow valve is communicated with the oil return pipeline, and the direct-push oil cylinder carries out high-pressure oil unloading before the.
According to one aspect of the invention, the system further comprises a lifting plate cylinder and a third reversing valve, wherein the third reversing valve is connected with the main pressure oil path, two oil outlets of the third reversing valve are respectively connected with a rod cavity and a rodless cavity of the lifting plate cylinder, the third reversing valve is further communicated with an oil return pipeline, and the lifting plate cylinder is unloaded with high-pressure oil before the third reversing valve performs reversing operation.
In accordance with one aspect of the invention, the system further includes a two-position, two-way solenoid valve connecting the rodless chamber of the lift plate cylinder with the third directional valve.
According to one aspect of the invention, the straight push cylinder and the rising plate cylinder are both gradually throttling type buffer cylinders.
According to one aspect of the invention, the system further comprises a selection valve and a first pump body high-pressure overflow valve, wherein an oil inlet of the selection valve is arranged on a main pressure oil path between the first pump body and the first reversing valve, two oil outlets of the selection valve are respectively connected with the first pump body low-pressure overflow valve and the first pump body high-pressure overflow valve, and the first pump body low-pressure overflow valve and the first pump body high-pressure overflow valve are both communicated with the oil return pipeline.
In accordance with one aspect of the invention, the system further includes a second pump body connecting the hydraulic oil tank and the line pressure oil passage, and a check valve between the second pump body and the line pressure oil passage.
According to one aspect of the invention, the system further comprises a second pump body overflow valve connected to the pipeline between the second pump body and the check valve, the second pump body overflow valve being in communication with the return line.
According to one aspect of the invention, the first and second pumps are part of a tandem pump.
According to one aspect of the invention, the system further comprises a pressure sensor disposed on the main pressure oil path for detecting the oil pressure of the main pressure oil path, and a controller in control connection with the pressure sensor, the first direction valve, the second direction valve, the third direction valve, and the selector valve, respectively.
According to one aspect of the invention, the system further comprises a position switch, wherein the position switch is connected with the controller, and the position switch is arranged on one side, close to the feeding hopper, of the lifting plate oil cylinder.
The implementation of the invention has the advantages that: the first pump body extracts hydraulic oil from the hydraulic oil tank, the hydraulic oil sequentially passes through the first reversing valve, the second reversing valve and the buffer valve and then is sent into a rodless cavity of the direct-push oil cylinder so as to push the direct-push cylinder to advance rapidly, after the direct-push oil cylinder moves to the right position, the second reversing valve is closed, oil supply to the rodless cavity of the direct-push oil cylinder is stopped, high-pressure oil sealed between the rodless cavity of the direct-push oil cylinder and the buffer valve and the second reversing valve ensures that the front edge of the cart is compacted, before the second reversing valve is operated in a linear reversing mode, namely the direct-push oil cylinder retreats to recover the direct push, the second reversing valve, the first reversing valve and the first pump body low-pressure overflow valve are opened, the high-pressure oil sealed between the rodless cavity of the direct-push oil cylinder and the second reversing valve is recycled to the hydraulic oil tank through the oil return pipeline, and under the action of the buffer valve, therefore, the strong impact of the water hammer phenomenon is reduced, the loosening and oil leakage of a pipeline joint and even the damage of the pipeline are prevented, and the safety of an oil supply pipeline of the direct-push oil cylinder is greatly improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic view of an unloading buffer hydraulic system according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, an unloading buffer hydraulic system comprises a first pump body 1, a first reversing valve 2, a second reversing valve 3, a direct-push oil cylinder 4 and a first pump body low-pressure overflow valve, wherein the first pump body 1 is communicated with a hydraulic oil tank and the second reversing valve 3 through a main pressure oil path, two oil outlets of the second reversing valve 3 are respectively connected with two inlets of a buffer valve 17, two outlets of the buffer valve 17 are respectively connected with a rod cavity and a rodless cavity of the direct-push oil cylinder 4, an oil return port of the second reversing valve 3 is communicated with the hydraulic oil tank through an oil return pipeline, the first reversing valve 2 is arranged between the first pump body 1 and the second reversing valve 3, one low-pressure end of the first pump body is connected to a pipeline between the first pump body 1 and the first reversing valve 2, the other end of the first pump body is communicated with the oil return pipeline, and before the second reversing valve 3 performs a reversing operation, the direct-push oil cylinder 4 is unloaded with high-pressure oil through a cushion valve 17.
In the present embodiment, the first pump body 1 serves as a power transmission mechanism for hydraulic oil in the hydraulic system. In the process of forward compression by direct pushing, the first pump body 1 is started, the first reversing valve 2 is opened from a flow direction channel from the first pump body 1 to the second reversing valve 3, the second reversing valve 3 is opened through a passage of the buffer valve 17 to the rodless cavity of the direct-pushing oil cylinder 4, the low-pressure overflow valve of the first pump body is closed, hydraulic oil conveyed by the first pump body 1 is conveyed through a main pressure oil way and sequentially enters the rodless cavity of the direct-pushing oil cylinder 4 through the first reversing valve 2, the second reversing valve 3 and the buffer valve 17, and the rodless cavity of the direct-pushing oil cylinder 4 is increased in size, so that the rod cavity is compressed to push the direct-pushing to rapidly advance to push the compression. After the direct-push compression is in place, the second reversing valve 3 is closed, the low-pressure overflow valve of the first pump body is opened, pressure maintaining is carried out by high-pressure oil sealed among the second reversing valve 3, the buffer valve 17 and a rodless cavity of the direct-push oil cylinder 4, the front of the vehicle is compacted, and at the moment, hydraulic oil conveyed by the first pump body 1 flows back to a hydraulic oil tank through the low-pressure overflow valve of the first pump body in an unloading mode. Before the second reversing valve 3 performs reversing operation, namely before the second reversing valve 3 opens a passage leading to a rod cavity of the straight-pushing oil cylinder 4 through the buffer valve 17 to perform straight-pushing recovery operation, the passage leading to a rodless cavity of the straight-pushing oil cylinder 4 at the level of the buffer valve 17 and the second reversing valve 3 is opened, the flow direction passage from the second reversing valve 3 to the first pump body 1 of the first reversing valve 2 is opened, high-pressure oil sealed between the second reversing valve 3 and the buffer valve 17 and the rodless cavity of the straight-pushing oil cylinder 4 flows back to a hydraulic oil tank through an oil return pipeline after being unloaded through the buffer valve 17, the second reversing valve 3, the first reversing valve 2 and a low-pressure overflow valve of the first pump body in sequence, and then the straight-pushing recovery operation is performed, so that the strong impact of a water hammer phenomenon is reduced, the occurrence of oil leakage of a loose joint of the pipeline and even the pipeline breakage is prevented, and the safety of the.
After high-pressure oil between the second reversing valve 3 and the rodless cavity of the buffer valve 17 and the straight-pushing oil cylinder 4 is drained, the second reversing valve 3 executes reversing operation, the passage between the second reversing valve 3 and the rodless cavity of the buffer valve 17 and the straight-pushing oil cylinder 4 is opened, the flow direction channel from the first pump body 1 to the second reversing valve 3 is opened by the first reversing valve 2, the low-pressure overflow valve of the first pump body is closed, hydraulic oil conveyed by the first pump body 1 enters the rod cavity of the straight-pushing oil cylinder 4 through the buffer valve 17, and the rod cavity of the straight-pushing oil cylinder 4 is increased in size, so that the rod cavity is compressed to push the straight-pushing oil cylinder to be quickly recovered. Similarly, before the direct-push oil cylinder 4 drives the direct push again to push and compress, the high-pressure oil unloading work with the same principle is executed, and the high-pressure oil sealed between the second reversing valve 3 and the buffer valve 17 and between rod cavities of the direct-push oil cylinder 4 is unloaded, so that the water hammer phenomenon is prevented.
Referring to fig. 1, in a preferred embodiment of the present invention, the system further includes a selector valve 6 and a first pump body high-pressure overflow valve 7, an oil inlet of the selector valve 6 is connected to a main pressure oil path between the first pump body 1 and the first reversing valve 2, two oil outlets of the selector valve 6 are respectively connected to the first pump body low-pressure overflow valve and the first pump body high-pressure overflow valve 7, and both the first pump body low-pressure overflow valve and the first pump body high-pressure overflow valve 7 are communicated with an oil return line. The selector valve 6 is used for selecting the opening or closing of the first pump body low-pressure overflow valve and/or the first pump body high-pressure overflow valve 7. In the invention, the first pump body high-pressure overflow valve 7 plays a role in constant-pressure overflow and pressure-stabilizing protection of a main pressure oil path. In the process of forward compression of the direct-push oil cylinder 4, the channel between the selection valve 6 and the first pump body high-pressure overflow valve 7 is selected to be opened, the direct-push oil cylinder 4 drives direct push to perform powerful compression on materials, when the main pressure oil way oil cylinder reaches a specific value, redundant hydraulic oil can be discharged through the first pump body high-pressure overflow valve 7, the maximum pressure of a main pressure pipeline is limited, and the effect of protecting a hydraulic system is achieved. In the process of solving the problem that the high-pressure oil between the second reversing valve 3 and the buffer valve 17 and the rodless cavity of the direct-push oil cylinder 4 is unloaded by the high-pressure overflow valve 7 of the first pump body to solve the water hammer phenomenon of the direct-push oil cylinder 4, the channel of the low-pressure overflow valve of the first pump body needs to be opened to unload the hydraulic oil.
As shown in fig. 1, in a preferred embodiment of the present invention, the system further includes a second pump body 8 and a check valve 9, the second pump body 8 connects the hydraulic oil tank and the line pressure oil path, and the check valve 9 is located between the second pump body 8 and the line pressure oil path. The second pump body 8 is mainly used for increasing the driving power of the hydraulic system and improving the working efficiency of the system, including the efficiency of the direct-push oil cylinder 4 for driving the direct-push extension and retraction and the working efficiency of the lifting plate oil cylinder 11 for loading and unloading. The check valve 9 is used for protecting the second pump body 8, and when the pressure in the main pressure oil circuit of the main hydraulic system is lower than the set value of the pressure reducing valve, oil liquid is prevented from flowing backwards, and the second pump body 8 is prevented from being damaged. Preferably, in this embodiment, the hydraulic oil pump is a dual pump, the dual pump is driven by the motor 16, the first pump body 1 and the second pump body 8 are components of the dual pump, and the dual pump supplies oil to the main pressure oil path at the same time, so as to supply oil to the direct thrust oil cylinder 4 and the lifting plate oil cylinder 11, which will be described below, and improve the oil supply efficiency, thereby improving the working efficiency of the whole hydraulic unloading system.
In the preferred embodiment shown in fig. 1, the system further includes a second pump body overflow valve 10, the second pump body overflow valve 10 is connected to a pipe between the second pump body 8 and the check valve 9, and the second pump body overflow valve 10 is communicated with the oil return pipe. The second pump body overflow valve 10 is opened when the hydraulic pressure in the main pressure oil path reaches the preset unloading pressure value of the second pump body 8, so that the hydraulic oil output by the second pump body 8 flows into the oil return pipeline through the second pump body overflow valve 10, is unloaded and returns to the hydraulic oil tank, and the hydraulic oil is conveyed only by using the first pump body 1, thereby preventing the motor 16 from being overloaded and damaging the driving motor 16.
Referring to fig. 1, in a preferred embodiment of the present invention, the system further includes a lifting plate cylinder 11 and a third directional valve 12, the third directional valve 12 is connected to the main pressure oil path, two oil outlets of the third directional valve 12 are respectively connected to a rod chamber and a rodless chamber of the lifting plate cylinder 11, the third directional valve 12 is further communicated to an oil return line, and before the third directional valve 12 performs a directional operation, the lifting plate cylinder 11 is unloaded by high-pressure oil.
In the present embodiment, the first pump body 1 and/or the second pump body 8 serve as a power transmission mechanism for hydraulic oil in the hydraulic system. The lifting plate oil cylinder 11 and the straight push oil cylinder 4 can use the same hydraulic circuit, and can play a role in simplifying hydraulic pipelines and reducing use cost. When the direct-push oil cylinder 4 drives the direct push to perform compression work, the third reversing valve 12 keeps a closed state, and the lifting plate oil cylinder 11 does not participate in the work of the hydraulic unloading system. The upper lifting plate oil cylinder 11 drives the feeding hopper to be charged and discharged for overshoot, the second reversing valve 3 keeps a closed state, the direct pushing oil cylinder 4 does not participate in the work of the hydraulic unloading system, and the work between the upper lifting plate oil cylinder 11 and the direct pushing oil cylinder 4 is complementally influenced. Preferably, the second reversing valve 3 and the third reversing valve 12 are both normally closed type reversing valves, and the number of the joints of the reversing valves is ensured to be enough to ensure that the main pressure oil path, the oil return pipeline and the straight push oil cylinder 4 or the lifting plate oil cylinder 11 are normally connected.
The hydraulic driving process of the lifting plate oil cylinder 11 is the same as the driving process principle of the straight push oil cylinder 4. In the process of lifting the feeding hopper by the lifting plate cylinder 11, the first pump body 1 is started, the first reversing valve 2 is opened from a flow direction channel from the first pump body 1 to the third reversing valve 12, the third reversing valve 12 is opened through a channel of a rodless cavity of the lifting plate cylinder 11, a low-pressure overflow valve of the first pump body is closed, hydraulic oil conveyed by the first pump body 1 is conveyed through a main pressure oil way and sequentially enters the rodless cavity of the lifting plate cylinder 11 through the first reversing valve 2 and the third reversing valve 12, and the rodless cavity of the lifting plate cylinder 11 is increased in size, so that the rod cavity is compressed to drive the feeding hopper to be quickly lifted, and materials are compressed. After the feeding hopper is lifted to a proper position, the third reversing valve 12 is closed, the low-pressure overflow valve of the first pump body is opened, pressure maintaining is carried out by high-pressure oil sealed between the third reversing valve 12 and the rodless cavity of the lifting plate oil cylinder 11, the front end is guaranteed to be compacted, and at the moment, hydraulic oil conveyed by the first pump body 1 flows back to the hydraulic oil tank through the unloading of the low-pressure overflow valve of the first pump body. Before the third reversing valve 12 performs reversing operation, that is, before the third reversing valve 12 opens a passage of a rod cavity of the rising plate cylinder 11 to perform feeding hopper recovery operation, a passage of a rodless cavity of the third reversing valve 12 and the rising plate cylinder 11 is opened, a flow direction passage of the first reversing valve 2 from the third reversing valve 12 to the first pump body 1 is opened, and high-pressure oil sealed between the third reversing valve 12 and the rodless cavity of the rising plate cylinder 11 flows back to the hydraulic oil tank through an unloading oil return pipeline by sequentially passing through the third reversing valve 12, the first reversing valve 2 and a low-pressure overflow valve of the first pump body, and then the feeding hopper recovery operation is performed, so that the strong impact of a water hammer phenomenon is reduced, the occurrence of loosening and oil leakage of a pipeline joint and even pipeline damage is prevented, and the safety of an oil supply pipeline of the rising plate cylinder 11 is greatly improved.
After high-pressure oil between the third reversing valve 12 and the rodless cavity of the rising plate oil cylinder 11 is drained, the third reversing valve 12 executes reversing operation, a passage between the third reversing valve 12 and the rod cavity of the rising plate oil cylinder 11 is opened, the first reversing valve 2 is opened from a flow channel from the first pump body 1 to the third reversing valve 12, a low-pressure overflow valve of the first pump body is closed, hydraulic oil conveyed by the first pump body 1 is used for lifting the rod cavity of the rising plate oil cylinder 11, and the volume of the rod cavity of the rising plate oil cylinder 11 is increased, so that the rod cavity is compressed to drive the feeding hopper to be quickly recovered.
Similarly, in the process that the feeding hopper is driven by the lifting plate oil cylinder 11 to lift, the channel between the selection valve 6 and the first pump body high-pressure overflow valve 7 is opened, when the feeding hopper carries out feeding under a strong load, when the main pressure oil way oil cylinder reaches a specific value, redundant hydraulic oil can be discharged through the first pump body high-pressure overflow valve 7, so that the maximum pressure of the main pressure pipeline is limited, and the effect of protecting a hydraulic system is achieved. In the process of solving the problem that the high-pressure oil of the first pump body high-pressure overflow valve 7 unloads the high-pressure oil between the third reversing valve 12 and the rodless cavity of the feeding hopper to solve the water hammer phenomenon of the lifting plate cylinder 11, the channel of the first pump body low-pressure overflow valve needs to be opened to unload the hydraulic oil. Similarly, the second pump body 8, the check valve 9 and the high-pressure overflow valve of the second pump body 8 have similar functions in the process of directly pushing the oil cylinder 4 and the lifting plate oil cylinder 11.
As shown in fig. 1, the system according to a preferred embodiment of the present invention further includes a two-position two-way solenoid valve 13, and the two-position two-way solenoid valve 13 connects the rodless chamber of the lift plate cylinder 11 and the third direction valve 12. In this embodiment, two-position two-way solenoid valve 13 is additionally arranged between the rodless cavity of ascending plate cylinder 11 and third reversing valve 12, when ascending plate cylinder 11 drives the feeding hopper to descend, if the main pressure oil line pipeline bursts due to too high internal pressure or pipeline aging, an operator only needs to timely release an operating button, so that two-position two-way solenoid valve 13 is closed, hydraulic oil in the rodless cavity of two-position two-way solenoid valve 13 and ascending plate cylinder 11 cannot escape, the feeding hopper can timely stop descending, the feeding hopper is prevented from being damaged or the worker is prevented from generating danger, and the safety of property and life is greatly improved.
As a preferred embodiment of the invention, the straight push oil cylinder 4 and the rising plate oil cylinder 11 are both gradually-throttling type buffer oil cylinders. By adopting the gradually-changed throttling type buffer oil cylinder, in the process that the straight-pushing oil cylinder 4 is extended in place or retracted in place, under the action of the gradually-changed throttling opening of the small cavity in the oil cylinder, the deceleration acceleration of the oil cylinder is gradually increased, and the movement speeds of the straight-pushing oil cylinder 4 and the straight-pushing oil cylinder are rapidly reduced, so that the impact of the straight-pushing oil cylinder 4 on a hydraulic oil pipeline is reduced, the hard impact of the straight-pushing is avoided, and the functions of protecting the hydraulic pipeline and a straight-pushing rigid structure are achieved. In the process that the lifting plate oil cylinder 11 is about to ascend or descend in place, the deceleration acceleration of the oil cylinder is gradually increased under the action of the gradually-changed throttling opening of the small cavity in the oil cylinder, and the movement speed of the direct-push oil cylinder 4 and the direct-push oil cylinder is rapidly reduced, so that the impact of the lifting plate oil cylinder 11 on a hydraulic oil pipeline is reduced, the hard impact of a feeding hopper is avoided, and the effect of protecting the hydraulic pipeline and the rigid structure of the feeding hopper is achieved.
As a preferred embodiment of the present invention, the system further includes a pressure sensor 14, the pressure sensor 14 is disposed on the main pressure oil path, the pressure sensor 14 is used for detecting the oil pressure of the main pressure oil path, and a controller (not shown) is in control connection with the pressure sensor 14, the first direction changing valve 2, the second direction changing valve 3, the third direction changing valve 12 and the selector valve 6, respectively. The controller is used for controlling the on-off of the first reversing valve 2, the second reversing valve 3, the third reversing valve 12 and the selector valve 6, so that oil path selection can be conveniently carried out. Preferably, the unloading pressure value of the second pump body 8 and the high pressure value of the main pressure oil path when the straight-pushing oil cylinder 4 works, and the unloading pressure value of the second pump body 8 and the high pressure value of the main pressure oil path when the lifting plate oil cylinder 11 works are preset in the controller. When the direct-push oil cylinder 4 works, the work comprises the process that the direct-push oil cylinder 4 drives the direct-push to compress the front end and recover the direct-push oil, the pressure sensor 14 detects the pressure value in the main pressure oil circuit in real time and feeds back the pressure value to the controller, when the pressure value detected by the pressure sensor 14 reaches the unloading pressure value of the second pump body 8 preset in the controller, the controller orders to open the overflow valve 10 of the second pump body, so that the hydraulic oil output by the second pump body 8 flows into an oil return pipeline through the overflow valve 10 of the second pump body, the unloading returns to the hydraulic oil tank, at the moment, only the first pump body 1 is used for conveying the hydraulic oil, thereby preventing the motor 16 from overloading, causing damage to the driving motor 16 and simultaneously ensuring the compression efficiency. The direct-push oil cylinder 4 continues to work under the oil supply of the first pump body 1, when the pressure sensor 14 detects that the pressure value in the main pressure oil circuit reaches a preset high pressure value in the controller, the direct-push oil cylinder 4 is indicated to be stretched out in place or the material in the material box is full, at the moment, the direct-push oil cylinder 4 does not need to be supplied with oil to protect a hydraulic pipeline, the controller commands the second reversing valve 3 to be closed, the low-pressure overflow valve of the first pump body is opened, pressure maintaining is carried out by high-pressure oil sealed between the second reversing valve 3 and a rodless cavity of the direct-push oil cylinder 4, the material is guaranteed to be compacted, and meanwhile, hydraulic oil conveyed by the first pump body 1 flows back to the hydraulic oil tank through the low-.
Similarly, when the lifting plate cylinder 11 works, the work includes the process that the lifting plate cylinder 11 drives the feeding hopper to carry out feeding and feeding hopper recovery, the pressure sensor 14 detects the pressure value in the main pressure oil path in real time and feeds back the pressure value to the controller, when the pressure value detected by the pressure sensor 14 reaches the unloading pressure value of the second pump body 8 preset in the controller, the controller orders to open the overflow valve 10 of the second pump body, so that the hydraulic oil output by the second pump body 8 flows into the oil return pipeline through the overflow valve 10 of the second pump body, and the unloading returns to the hydraulic oil tank, at the moment, only the first pump body 1 is used for conveying the hydraulic oil, thereby preventing the motor 16 from overloading, and causing damage to the driving motor 16 and improving the feeding efficiency. In a specific embodiment, the controller is a single chip microcomputer or a PLC, and the single chip microcomputer may be a 51-series single chip microcomputer, and the specific types are as follows: AT89S51, STC12C2051, the PLC can be Siemens S7-200CN, S7-200, S7-300, and the like, and the control technology of the single chip microcomputer and the PLC is mature, so that the description is omitted.
Referring to the embodiment shown in fig. 1, the system further includes a position switch 15, the position switch 15 is connected to the controller, and the position switch 15 is disposed on a side of the lifting plate cylinder 11 close to the feeding hopper. In the process that the upper lifting plate oil cylinder 11 drives the upper hopper to recover and descend, when the upper hopper descends to the position switch 15 and the position switch 15 detects a sensing signal, the position switch 15 sends the sensing signal to the controller, the controller commands the selector valve 6 to close the first pump high-pressure overflow valve 7 and open the first pump low-pressure overflow valve, so that the oil pressure in a main pressure oil path is reduced, the lower pressure of the upper hopper is used for descending, the situation that the driving pressure is too high in the descending process of the upper hopper and the compression box is displaced due to the fact that the stop position of the upper hopper is too high is avoided. In particular, the position switch 15 may be a proximity switch or a travel switch.
Referring to fig. 1, the second reversing valve 3 and the third reversing valve 12 are three-position four-way electromagnetic reversing valves or three-position four-way electro-hydraulic reversing valves, and the valve pipeline interfaces just meet the requirements of the hydraulic unloading system of the invention. Preferably, the second reversing valve 3 and the third reversing valve 12 are O-shaped normally closed reversing valves, and only valves needing to be opened are selected when the valve is used, so that the valve is convenient to use and high in pipeline safety performance. Specifically, the first directional valve 2 may be a two-position two-way electromagnetic directional valve, a two-position three-way electromagnetic directional valve, a two-position four-way electromagnetic directional valve, or the like, and the flow direction of the hydraulic oil between the first pump body 1 and the second directional valve 3 may be selected, and the selector valve 6 may be a three-position four-way H-type electromagnetic directional valve. The valves are all the existing mature products, and the specific power-on control mode is not repeated.
The implementation of the invention has the advantages that: the first pump body extracts hydraulic oil from the hydraulic oil tank, the hydraulic oil sequentially passes through the first reversing valve, the second reversing valve and the buffer valve and then is sent into a rodless cavity of the direct-push oil cylinder so as to push the direct-push cylinder to advance rapidly, after the direct-push oil cylinder moves to the right position, the second reversing valve is closed, oil supply to the rodless cavity of the direct-push oil cylinder is stopped, high-pressure oil sealed between the rodless cavity of the direct-push oil cylinder and the buffer valve and the second reversing valve ensures that the front edge of the cart is compacted, before the second reversing valve is operated in a linear reversing mode, namely the direct-push oil cylinder retreats to recover the direct push, the second reversing valve, the first reversing valve and the first pump body low-pressure overflow valve are opened, the high-pressure oil sealed between the rodless cavity of the direct-push oil cylinder and the second reversing valve is recycled to the hydraulic oil tank through the oil return pipeline, and under the action of the buffer valve, therefore, the strong impact of the water hammer phenomenon is reduced, the loosening and oil leakage of a pipeline joint and even the damage of the pipeline are prevented, and the safety of an oil supply pipeline of the direct-push oil cylinder is greatly improved.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention disclosed herein are intended to be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. The hydraulic unloading system is characterized by comprising a first pump body, a first reversing valve, a second reversing valve, a direct-push oil cylinder and a first pump body low-pressure overflow valve, wherein the first pump body is communicated with a hydraulic oil tank and the second reversing valve through a main pressure oil way, two oil outlets of the second reversing valve are respectively connected with two access ports of a buffer valve, two output ports of the buffer valve are respectively connected with a rod cavity and a rodless cavity of the direct-push oil cylinder, an oil return port of the second reversing valve is communicated with the hydraulic oil tank through an oil return pipeline, the first reversing valve is arranged between the first pump body and the second reversing valve, one end of the first pump body low-pressure overflow valve is connected onto a pipeline between the first pump body and the first reversing valve, the other end of the first pump body low-pressure overflow valve is communicated with the oil return pipeline, and the direct-push oil cylinder is unloaded by high-pressure oil before the second reversing.
2. The hydraulic unloading system of claim 1, further comprising a lift plate cylinder and a third directional valve, wherein the third directional valve is connected to the main pressure oil path, two oil outlets of the third directional valve are respectively connected to a rod chamber and a rodless chamber of the lift plate cylinder, the third directional valve is further communicated to an oil return line, and the lift plate cylinder is unloaded with high pressure oil before the third directional valve performs a directional operation.
3. The hydraulic unloading system of claim 2, further comprising a two-position, two-way solenoid valve connecting the rodless chamber of the lift plate cylinder and the third directional valve.
4. The hydraulic unloading system of claim 1, wherein the thrust cylinder and the lift plate cylinder are both gradual throttling buffer cylinders.
5. The hydraulic unloading system of claim 1, further comprising a selector valve and a first pump body high pressure overflow valve, wherein an oil inlet of the selector valve is connected to the main pressure oil path between the first pump body and the first reversing valve, two oil outlets of the selector valve are respectively connected to the first pump body low pressure overflow valve and the first pump body high pressure overflow valve, and both the first pump body low pressure overflow valve and the first pump body high pressure overflow valve are communicated with the oil return line.
6. The hydraulic unloading system of claim 5, further comprising a second pump body connecting the hydraulic tank to the line pressure gallery, and a one-way valve between the second pump body and the line pressure gallery.
7. The hydraulic unloading system of claim 6, further comprising a second pump body overflow valve connected to a conduit between the second pump body and the check valve, the second pump body overflow valve being in communication with the return line.
8. The hydraulic unloading system of claim 6, wherein the first and second pumps are part of a tandem pump.
9. The hydraulic unloading system of any one of claims 1 to 8, further comprising a pressure sensor disposed on the main pressure oil path for detecting an oil pressure of the main pressure oil path, and a controller in control connection with the pressure sensor, the first directional valve, the second directional valve, the third directional valve, and the selector valve, respectively.
10. The hydraulic unloading system of claim 9, further comprising a position switch coupled to the controller, the position switch being disposed on a side of the lift plate cylinder adjacent to the upper bucket.
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| CN202010117492.8A CN111365310A (en) | 2020-02-25 | 2020-02-25 | Hydraulic unloading system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010117492.8A CN111365310A (en) | 2020-02-25 | 2020-02-25 | Hydraulic unloading system |
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| CN111365310A true CN111365310A (en) | 2020-07-03 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115853753A (en) * | 2022-12-22 | 2023-03-28 | 中国第一汽车股份有限公司 | Oil pump unloading system, method, storage medium and vehicle |
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