CN110566527B - Hydraulic drive system - Google Patents
Hydraulic drive system Download PDFInfo
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- CN110566527B CN110566527B CN201910916730.9A CN201910916730A CN110566527B CN 110566527 B CN110566527 B CN 110566527B CN 201910916730 A CN201910916730 A CN 201910916730A CN 110566527 B CN110566527 B CN 110566527B
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- oil
- reversing valve
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- differential
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- 238000003860 storage Methods 0.000 claims abstract description 20
- 238000004891 communication Methods 0.000 claims description 9
- 239000003921 oil Substances 0.000 description 455
- 239000010720 hydraulic oil Substances 0.000 description 71
- 230000001960 triggered effect Effects 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000004064 recycling Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 230000001360 synchronised effect Effects 0.000 description 2
- 230000007306 turnover Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
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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
- F15B11/22—Synchronisation of the movement of two or more servomotors
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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
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/28—Means for indicating the position, e.g. end of stroke
- F15B15/2807—Position switches, i.e. means for sensing of discrete positions only, e.g. limit switches
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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
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
- F15B2211/7114—Multiple output members, e.g. multiple hydraulic motors or cylinders with direct connection between the chambers of different actuators
- F15B2211/7121—Multiple output members, e.g. multiple hydraulic motors or cylinders with direct connection between the chambers of different actuators the chambers being connected in series
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
The present invention relates to a hydraulic drive system. The hydraulic driving system comprises an oil pump, a first reversing valve, a differential oil cylinder, a plunger oil cylinder and a hydraulic compensation structure; the differential oil cylinder is provided with a rod cavity and a rodless cavity; the oil outlet end of the oil pump is communicated with the oil inlet of the first reversing valve, the first working oil port of the first reversing valve is communicated with the rodless cavity of the differential oil cylinder, and the rod cavity of the differential oil cylinder is communicated with the plunger oil cylinder through pipelines; the oil return port of the first reversing valve is used for communicating with the oil storage tank; the hydraulic compensation structure is used for controlling the rod cavity of the differential oil cylinder to be communicated with the first working oil port of the first reversing valve or controlling the plunger oil cylinder to be communicated with the oil storage tank.
Description
Technical Field
The invention relates to the technical field of hydraulic control, in particular to a hydraulic driving system.
Background
The hydraulic driving system converts the pressure energy of hydraulic oil into mechanical energy of an executing element, so that the executing element acts to drive equipment to execute specified actions. When the power required for driving the equipment to execute the specified action is large or one oil cylinder cannot meet the requirement of action stability, two oil cylinders for synchronous action are required to be arranged. For example, the overturning platform comprises two overturning arms, and each overturning arm needs an oil cylinder to overturn, so that in order to ensure that each overturning arm overturns synchronously, two oil cylinders are needed to act synchronously.
Generally, a mode of connecting two cylinders in series is adopted to realize synchronous action of the two cylinders. However, in actual production, due to factors such as manufacturing errors, leakage in the cylinders, mixing of air in the hydraulic oil, etc., errors exist in the positions where the two cylinders connected in this way extend out when they are operated, and thus the production requirements cannot be satisfied.
Disclosure of Invention
Based on this, it is necessary to provide a hydraulic driving system that overcomes the above-mentioned drawbacks, in order to solve the technical problem that the two cylinders are out of position when they are extended in the prior art, and the errors cannot be satisfied in the production requirements.
A hydraulic driving system comprises an oil pump, a first reversing valve, a differential oil cylinder, a plunger oil cylinder and a hydraulic compensation structure; the differential oil cylinder is provided with a rod cavity and a rodless cavity;
the oil outlet end of the oil pump is communicated with the oil inlet of the first reversing valve, the first working oil port of the first reversing valve is communicated with the rodless cavity of the differential oil cylinder, and the rod cavity of the differential oil cylinder is communicated with the plunger oil cylinder through pipelines; the oil return port of the first reversing valve is used for communicating with an oil storage tank;
The hydraulic compensation structure is used for controlling the rod cavity of the differential oil cylinder to be communicated with the first working oil port of the first reversing valve or controlling the plunger oil cylinder to be communicated with an oil storage tank.
According to the hydraulic driving system, when the piston of the differential oil cylinder extends to the position at first and the extending position of the piston of the plunger oil cylinder needs to be compensated (the plunger oil cylinder does not extend to the position), the hydraulic compensation structure can be controlled so that the plunger oil cylinder is communicated with the first working oil port of the first reversing valve. At the moment, hydraulic oil output by an oil outlet end of the oil pump sequentially enters the plunger oil cylinder through an oil inlet of the first reversing valve and the first working oil port, so that a piston of the plunger oil cylinder is driven to extend continuously, the extending position of the piston of the plunger oil cylinder is compensated, and position errors of extending in-place of the pistons of the differential oil cylinder and the plunger oil cylinder are reduced or eliminated.
When the piston of the plunger cylinder is extended to the proper position first and the extending position of the piston of the differential cylinder needs to be compensated (the differential cylinder is not extended to the proper position), the hydraulic compensation structure can be controlled so that the rod cavity of the differential cylinder is communicated with the oil storage tank. At the moment, hydraulic oil output by an oil outlet end of the oil pump sequentially enters a rodless cavity of the differential oil cylinder through an oil inlet of the first reversing valve and a first working oil port, and hydraulic oil in the rod cavity of the differential oil cylinder is discharged to the oil storage tank, so that a piston of the differential oil cylinder is driven to extend continuously, the extending position of the piston of the differential oil cylinder is compensated, and the extending position errors of the pistons of the differential oil cylinder and the plunger oil cylinder are reduced or eliminated.
Therefore, the hydraulic driving system can compensate the position errors of the extending positions of the pistons of the differential cylinder and the plunger cylinder, so that the position errors are weakened or eliminated, and the production requirement is met.
In one embodiment, the hydraulic driving system further comprises a first hydraulic control one-way valve and a second hydraulic control one-way valve, wherein the first hydraulic control one-way valve and the second hydraulic control one-way valve are respectively provided with an oil inlet, an oil outlet and a control oil port;
the first hydraulic control one-way valve is arranged between the first reversing valve and the differential cylinder, an oil inlet of the first hydraulic control one-way valve is communicated with a first working oil port of the first reversing valve, and an oil outlet of the first hydraulic control one-way valve is communicated with a rodless cavity of the differential cylinder;
the second hydraulic control one-way valve is arranged between the differential oil cylinder and the plunger oil cylinder, an oil inlet of the second hydraulic control one-way valve is communicated with a rod cavity of the differential oil cylinder, and an oil outlet of the second hydraulic control one-way valve is communicated with the plunger oil cylinder;
and control oil ports of the first hydraulic control one-way valve and the second hydraulic control one-way valve are communicated with a second working oil port of the first reversing valve.
In one embodiment, the first reversing valve includes a first state and a second state;
when the first reversing valve is in the first state, an oil inlet of the first reversing valve is communicated with a first working oil port, and a second working oil port of the first reversing valve is communicated with an oil return port;
when the first reversing valve is in the second state, an oil inlet of the first reversing valve is communicated with the second working oil port, and a first working oil port of the first reversing valve is communicated with the oil return port.
In one embodiment, the hydraulic compensation structure comprises a second reversing valve, wherein the second reversing valve is provided with an oil inlet, a third working oil port and an oil return port;
the oil inlet of the second reversing valve is communicated with the first working oil port of the first reversing valve, the third working oil port of the second reversing valve is communicated with the rod cavity of the differential oil cylinder and the oil inlet of the second hydraulic control one-way valve, and the oil return port of the second reversing valve is used for communicating an oil storage tank.
In one embodiment, the second reversing valve includes a third state and a fourth state;
when the second reversing valve is in the third state, a third working oil port of the second reversing valve is communicated with the oil inlet;
When the second reversing valve is in the fourth state, the third working oil port of the second reversing valve is communicated with the oil return port.
In one embodiment, the hydraulic drive system further comprises a first travel switch, a second travel switch, and a controller; the first travel switch and the second travel switch are electrically connected to the controller; the controller is electrically connected with the first reversing valve and the second reversing valve;
the first travel switch and the second travel switch are respectively used for detecting the extending-out situation of the differential oil cylinder and the plunger oil cylinder;
during the extending action of the differential oil cylinder and the plunger oil cylinder: when the first travel switch detects that the differential oil cylinder stretches out to the position, the controller controls the first reversing valve to keep the first state, and the second reversing valve is in the third state; or alternatively
When the second travel switch detects that the plunger oil cylinder stretches out to the position, the controller controls the first reversing valve to keep the first state, and the second reversing valve is in the fourth state.
In one embodiment, the hydraulic compensating structure includes a third reversing valve and a fourth reversing valve; the third reversing valve and the fourth reversing valve are respectively provided with an oil inlet and an oil outlet; the oil inlet and the oil outlet of the third reversing valve can be controlled to be connected or disconnected, and the oil inlet and the oil outlet of the fourth reversing valve can be controlled to be connected or disconnected;
The oil inlet and the oil outlet of the third reversing valve are respectively communicated with the first working oil port of the first reversing valve and the oil inlet of the second hydraulic control one-way valve; the oil inlet of the fourth reversing valve is communicated between the rod cavity of the differential oil cylinder and the oil inlet of the second hydraulic control one-way valve, and the oil outlet of the fourth reversing valve is used for communicating an oil storage tank.
In one embodiment, the hydraulic drive system further comprises a first travel switch, a second travel switch, and a controller, the first travel switch and the second travel switch being electrically connected to the controller, the controller being electrically connected to the first reversing valve and the second reversing valve;
the first travel switch and the second travel switch are respectively used for detecting the extending-out situation of the differential oil cylinder and the plunger oil cylinder;
during the extending action of the differential oil cylinder and the plunger oil cylinder: when the first travel switch detects that the differential oil cylinder stretches out to the position, the controller controls the first reversing valve to keep the first state, the oil inlet and the oil outlet of the third reversing valve are communicated, and the oil inlet and the oil outlet of the fourth reversing valve are disconnected; or when the second travel switch detects that the plunger oil cylinder stretches out to the position, the controller controls the first reversing valve to keep the first state, the oil inlet and the oil outlet of the third reversing valve are disconnected, and the oil inlet and the oil outlet of the fourth reversing valve are connected.
In one embodiment, the hydraulic drive system further comprises a one-way throttle valve, and the one-way throttle valve is communicated with the first working oil port of the first reversing valve and the oil inlet of the first hydraulic control one-way valve.
In one embodiment, the hydraulic drive system further comprises a relief valve having an oil inlet and an oil outlet, the oil inlet of the relief valve being in communication with the oil outlet of the oil pump.
Drawings
FIG. 1 is a schematic diagram of a hydraulic drive system in accordance with an embodiment of the present invention;
fig. 2 is a schematic diagram of a hydraulic drive system in another embodiment of the invention.
Detailed Description
In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
As shown in fig. 1, a hydraulic driving system according to an embodiment of the present invention includes an oil pump 10, a first reversing valve 20, a differential cylinder 40, a plunger cylinder 50, and a hydraulic compensation structure.
The oil inlet end of the oil pump 10 is connected to an oil reservoir 100 for storing hydraulic oil, and the oil outlet end of the oil pump 10 is used for supplying high-pressure hydraulic oil to a hydraulic driving system.
The first reversing valve 20 has an oil inlet P1, an oil return port T1, a first working oil port A1, and a second working oil port B1. The differential cylinder 40 includes a cylinder body having an interior cavity and a piston 42 disposed in the cylinder body interior cavity, the piston 42 defining the cylinder body interior cavity as a rod-containing cavity 44 and a rod-free cavity 46. The specific structure of the differential cylinder 40 and the plunger cylinder 50 is well known in the art, and will not be described in detail herein.
The oil outlet end of the oil pump 10 is communicated with the oil inlet P1 of the first reversing valve 20 through a pipeline. The first working port A1 of the first reversing valve 20 is in communication with the rodless chamber 46 of the differential cylinder 40 through a pipe. The rod chamber 44 of the differential cylinder 40 is in communication with the plunger cylinder 50 via a conduit. The oil return port T1 of the first reversing valve 20 may be in communication with the oil reservoir 100 via a pipe.
The hydraulic pressure compensating structure is used to controllably communicate the rod chamber 44 of the differential cylinder 40 with the first working port A1 of the first direction valve 20, or to controllably communicate the plunger cylinder 50 with the reservoir tank 100.
In the hydraulic driving system, when the differential cylinder 40 and the plunger cylinder 50 need to extend simultaneously, the oil inlet P1 of the first reversing valve 20 is controlled to be communicated with the first working oil port A1, and the second working oil port B1 of the first reversing valve 20 is controlled to be communicated with the oil return port T2. Hydraulic oil output from an oil outlet end of the oil pump 10 sequentially enters the rodless cavity 46 of the differential oil cylinder 40 through the oil inlet P1 and the first working oil port A1 of the first reversing valve 20, so that a piston of the differential oil cylinder 40 is driven to extend. Meanwhile, as the piston 42 of the differential cylinder 40 protrudes, the hydraulic oil in the rod cavity 44 of the differential cylinder 40 is discharged into the plunger cylinder 50, so as to drive the piston of the plunger cylinder 50 to protrude, and at this time, the hydraulic oil in the plunger cylinder 50 is discharged into the oil storage tank 100 through the second working oil port B1 and the oil return port T1 of the first reversing valve 20.
When the differential cylinder 40 and the plunger cylinder 50 need to retract simultaneously, the oil inlet P1 of the first reversing valve 20 is controlled to be communicated with the second working oil port B1, and the first working oil port A1 is controlled to be communicated with the oil return port T1. The plunger cylinder 50 is retracted under the load, the hydraulic oil in the plunger cylinder 50 is discharged to the rod chamber 44 of the differential cylinder 40, and the hydraulic oil in the rod-less chamber 46 of the differential cylinder 40 is discharged and sequentially passes through the first working port A1 and the oil return port T1 of the first reversing valve 20 to the oil reservoir 100, thereby driving the piston 42 of the differential cylinder 40 to retract.
It can be seen that the hydraulic drive system described above achieves extension or retraction of the pistons of the differential cylinder 40 and the plunger cylinder 50 by reversing the direction of the first reversing valve 20.
In order to reduce or eliminate the positional error that exists in the extension of the pistons of the differential cylinder 40 and the plunger cylinder 50:
for example, when the piston of the differential cylinder 40 is first extended into position and the piston extension position of the plunger cylinder 50 needs to be compensated (i.e., the plunger cylinder 50 is not extended into position), the hydraulic compensation structure may be controlled such that the plunger cylinder 50 communicates with the first working port A1 of the first reversing valve 20. At this time, the hydraulic oil output from the oil outlet end of the oil pump 10 sequentially enters the plunger cylinder 50 through the oil inlet P1 and the first working oil port A1 of the first reversing valve 20, so as to drive the piston 52 of the plunger cylinder 50 to continue to extend, so as to compensate the extending position of the piston 52 of the plunger cylinder 50, and reduce or eliminate the positional errors of extending the pistons of the differential cylinder 40 and the plunger cylinder 50 in place.
For another example, when the piston 52 of the plunger cylinder 50 is first extended into position and compensation for the extended position of the piston 42 of the differential cylinder 40 is desired (the differential cylinder 40 is not extended into position), the hydraulic compensation structure may be controlled such that the rod chamber 44 of the differential cylinder 40 is in communication with the reservoir 100. At this time, the hydraulic oil output from the oil outlet end of the oil pump 10 sequentially enters the rodless cavity 46 of the differential cylinder 40 through the oil inlet P1 and the first working oil port A1 of the first reversing valve 20, and the hydraulic oil in the rod cavity 44 of the differential cylinder 40 is discharged to the oil storage tank 100, so as to drive the piston 42 of the differential cylinder 40 to continue to extend, so as to compensate the extending position of the piston 42 of the differential cylinder 40, and reduce or eliminate the extending position errors of the pistons of the differential cylinder 40 and the plunger cylinder 50.
In this way, the hydraulic drive system can compensate for the positional errors of the extended pistons of the differential cylinder 40 and the plunger cylinder 50, thereby reducing or eliminating the positional errors to meet the production requirements.
The hydraulic driving system can be applied to a turnover table, a traversing trolley, a wallboard trolley and the like, and the turnover or lifting of the working platform is realized through the telescopic action of the two oil cylinders. It will be appreciated that the hydraulic drive system of the present invention is not limited to use with the above-listed devices, but may be used with other devices, and is not limited thereto.
In an embodiment of the present invention, the hydraulic drive system further includes a relief valve 90, the relief valve 90 having an oil inlet and an oil outlet. The oil inlet of the relief valve 90 communicates with the oil outlet end of the oil pump 10. Thus, when the hydraulic driving system is over-pressurized, the oil inlet and the oil outlet of the safety valve 90 are communicated to release the pressure of the hydraulic driving system, so as to protect the hydraulic driving system. Preferably, the oil drain port of the relief valve 90 is connected to the oil reservoir 100 through a pipe so as to recover and reuse the discharged hydraulic oil.
In an embodiment of the present invention, the hydraulic drive system further includes a first pilot operated check valve 60 and a second pilot operated check valve 70. The first hydraulic check valve 60 and the second hydraulic check valve 70 each have an oil inlet, an oil outlet, and a control oil port.
The first pilot operated check valve 60 is disposed between the first reversing valve 20 and the differential cylinder 40, and an oil inlet of the first pilot operated check valve 60 is connected to the first working oil port A1 of the first reversing valve 20, and an oil outlet of the first pilot operated check valve 60 is connected to the rodless cavity 46 of the differential cylinder 40. The second hydraulic control one-way valve 70 is arranged between the plunger cylinder 50 and the differential cylinder 40, and an oil inlet of the second hydraulic control one-way valve 70 is communicated with the rod cavity 44 of the differential cylinder 40, and an oil outlet of the second hydraulic control one-way valve 70 is communicated with the plunger cylinder 50. Wherein, the control oil ports of the first hydraulic control check valve 60 and the second hydraulic control check valve 70 are both communicated with the second working oil port B1 of the first reversing valve 20.
It should be noted that, when the control ports of the hydraulic check valves (i.e., the first hydraulic check valve 60 and the second hydraulic check valve 70) are not filled with hydraulic oil, the hydraulic check valves (i.e., the first hydraulic check valve 60 and the second hydraulic check valve 70) are only turned on in the forward direction, i.e., the direction from the oil inlet to the oil outlet is turned on, and the direction from the oil outlet to the oil inlet is turned off. When the hydraulic oil is introduced into the control oil ports of the hydraulic check valves (i.e., the first hydraulic check valve 60 and the second hydraulic check valve 70), the hydraulic check valves (i.e., the first hydraulic check valve 60 and the second hydraulic check valve 70) are only turned on reversely, i.e., the direction from the oil outlet to the oil inlet is turned on, and the direction from the oil inlet to the oil outlet is turned off.
In this way, the arrangement of the first hydraulic check valve 60 and the second hydraulic check valve 70 prevents the hydraulic oil in the rodless chamber 46 of the differential cylinder 40 and the plunger cylinder 50 from flowing out under the load of the differential cylinder 40 and the plunger cylinder 50, thereby preventing the pistons of the differential cylinder 40 and the plunger cylinder 50 from retracting, and ensuring that the working platform supported by the differential cylinder 40 and the plunger cylinder 50 can stay at a certain position for a long time without significantly descending or tilting.
In particular embodiments, the hydraulic drive system further includes a one-way throttle valve 80. The one-way throttle valve 80 is communicated between the first working oil port A1 of the first reversing valve 20 and the oil inlet of the first pilot operated one-way valve 60. In this way, the one-way throttle valve 80 is used to control the flow rate of hydraulic oil discharged from the rodless chamber 46 of the differential cylinder 40 and the plunger cylinder 50, so as to control the speed of retraction of the pistons of the differential and plunger cylinders 50, and prevent the occurrence of safety accidents due to too fast retraction of the pistons of the differential cylinder 40 and the plunger cylinder 50.
In particular embodiments, the first reversing valve 20 includes a first state and a second state. When the first reversing valve 20 is in the first state, the oil inlet P1 of the first reversing valve 20 is communicated with the first working oil port A1, and the second working oil port B1 of the first reversing valve 20 is communicated with the oil return port T1. At this time, the hydraulic oil output from the oil pump 10 may sequentially enter the rodless cavity 46 of the differential cylinder 40 through the oil inlet P1 and the first working oil port A1 of the first reversing valve 20 and the first pilot operated check valve 60, and the hydraulic oil in the rod cavity 44 of the differential cylinder 40 enters the plunger cylinder 50 through the second pilot operated check valve 70, so as to drive the pistons of the differential cylinder 40 and the plunger cylinder 50 to extend.
When the first reversing valve 20 is in the second state, the oil inlet P1 of the first reversing valve 20 is communicated with the second working oil port B1, and the first working oil port A1 of the first reversing valve 20 is communicated with the oil return port T1. At this time, the hydraulic oil output from the oil pump 10 can enter the control ports of the first hydraulic check valve 60 and the second hydraulic check valve 70 through the oil inlet P1 and the second working port B1 of the first reversing valve 20, so that the first hydraulic check valve 60 and the second hydraulic check valve 70 are reversely conducted. At this time, under the action of the load, the piston of the plunger cylinder 50 is retracted, so that the hydraulic oil in the plunger cylinder 50 is discharged to the rod chamber 44 of the differential cylinder 40, and the hydraulic oil in the rodless chamber 46 of the differential cylinder 40 is sequentially discharged to the oil tank 100 through the first pilot operated check valve 60 and the first working oil port A1 and the oil return port T1 of the first reversing valve 20. I.e., the piston retracting actions of the differential cylinder 40 and the plunger cylinder 50. Alternatively, the first direction valve 20 may be an electromagnetic direction valve, so that the state of the first direction valve 20 may be controlled by controlling the energization or de-energization of the electromagnet of the electromagnetic direction valve.
It should be noted that, in one embodiment, the oil return port T1 of the first reversing valve 20 is connected to the oil reservoir 100 through a pipe, so as to facilitate recycling of the discharged hydraulic oil. It will be appreciated that the oil return port of the first reversing valve 20 and the oil inlet port of the oil pump 10 may be connected to the same reservoir or to different reservoirs.
Further, the first reversing valve 20 also includes a closed state. When the first reversing valve 20 is in the closed state, the oil inlet P1 of the first reversing valve 20 is directly communicated with the oil return port T1. At this time, the hydraulic oil output from the oil pump 10 is sequentially discharged through the oil inlet P1 and the oil return port T1 of the first reversing valve 20, thereby locking the hydraulic driving system, and facilitating the maintenance of the states of the differential cylinder 40 and the plunger cylinder 50.
In one embodiment, the hydraulic compensating structure includes a second reversing valve 30. The second reversing valve 30 has an oil inlet P2, a third working oil port A2, and an oil return port T2. The oil inlet P2 of the second directional valve 30 is communicated with the first working oil port A1 of the first directional valve 20. The third working oil port A2 of the second reversing valve 30 is communicated between the rod cavity 44 of the differential cylinder 40 and the oil inlet of the second hydraulic control one-way valve 70, and the oil return port T2 of the second reversing valve 30 is communicated with the oil storage tank 100. Alternatively, the second directional valve 30 may be an electromagnetic directional valve, so that the state of the electromagnetic directional valve may be controlled by energizing or de-energizing the electromagnet of the electromagnetic directional valve. The oil return port T2 of the second reversing valve 30 is connected to the oil reservoir 100 through a pipe, so as to recycle the discharged hydraulic oil. It is to be understood that the oil return port T2 of the second reversing valve 30 may be connected to the same oil tank at the oil inlet end of the oil pump 10, or may be connected to a different oil tank, which is not limited herein.
In this way, in the process of extending the pistons of the differential cylinder 40 and the plunger cylinder 50, when the differential cylinder 40 is extended to the proper position first and compensation is required for the extended position of the plunger cylinder 50 (the piston 52 of the plunger cylinder 50 is not extended to the proper position), the first reversing valve 20 can be controlled to maintain the first state, and the oil inlet P2 of the second reversing valve 30 and the third working oil port A2 are controlled to be conducted. At this time, the hydraulic oil output from the oil pump 10 sequentially passes through the oil inlet P1 and the first working oil port A1 of the first reversing valve 20, and the oil inlet P2 and the third working oil port A2 of the second reversing valve 30, and then enters the plunger cylinder 50 through the second hydraulic control check valve 70, so that the piston 52 of the plunger cylinder 50 continues to extend until reaching the extending position, that is, the positional errors of extending the pistons of the differential cylinder 40 and the plunger cylinder 50 into position are eliminated.
In the process of extending the pistons of the differential cylinder 40 and the plunger cylinder 50, when the plunger cylinder 50 is extended to the first position and the extending position of the differential cylinder 40 needs to be compensated (the piston 42 of the differential cylinder 40 is not extended to the first position), the first reversing valve 20 is controlled to be kept in the first state, and the third working oil port A2 and the oil return port T2 of the second reversing valve 30 are controlled to be conducted. At this time, the hydraulic oil output from the oil pump 10 sequentially passes through the oil inlet P1 and the first working oil port A1 of the first reversing valve 20, and then enters the rodless cavity 46 of the differential cylinder 40 through the first pilot operated check valve 60, and the hydraulic oil in the rod cavity 44 of the differential cylinder 40 is discharged to the oil storage tank 100 through the third working oil port A2 and the oil return port T2 of the second reversing valve 30, so that the piston 42 of the differential cylinder 40 continues to extend until reaching the extending position, that is, the position error of the extending position of the pistons of the differential cylinder 40 and the plunger cylinder 50 is eliminated.
In the process of retracting the pistons of the differential cylinder 40 and the plunger cylinder 50, when the differential cylinder 40 is first retracted to the retracted position and the retracted position of the plunger cylinder 50 needs to be compensated (i.e. the piston 52 of the plunger cylinder 50 is not retracted), the first reversing valve 20 is controlled to maintain the second state, and the third working oil port A2 and the oil return port T2 of the second reversing valve 30 are controlled to be conducted. At this time, the hydraulic oil output from the oil pump 10 sequentially enters the control oil ports of the first hydraulic check valve 60 and the second hydraulic check valve 70 through the oil inlet P1 and the second working oil port B1 of the first reversing valve 20, so that the first hydraulic check valve 60 and the second hydraulic check valve 70 are reversely conducted. At this time, the hydraulic oil in the plunger cylinder 50 may be sequentially discharged to the oil reservoir 100 through the second pilot operated check valve 70 and the third working oil port A2 and the oil return port T2 of the second reversing valve 30, so that the piston 52 of the plunger cylinder 50 may continue to retract under the load until reaching the retracted position, that is, the position errors of the differential cylinder 40 and the piston of the plunger cylinder 50 in the retracted position are eliminated.
It should be noted that, during the retraction process of the pistons of the differential cylinder 40 and the plunger cylinder 50, when the piston 42 of the differential cylinder 40 is first retracted to the retracted position, and the retracted position of the piston 52 of the plunger cylinder 50 needs to be compensated, the third working oil port A2 and the oil inlet P2 of the second reversing valve 30 may also be controlled to be conducted. At this time, the hydraulic oil output from the oil pump 10 sequentially enters the control oil ports of the first hydraulic check valve 60 and the second hydraulic check valve 70 through the oil inlet P1 and the second working oil port B1 of the first reversing valve 20, so that the first hydraulic check valve 60 and the second hydraulic check valve 70 are reversely conducted. At this time, the hydraulic oil in the plunger cylinder 50 may be sequentially discharged to the oil reservoir 100 through the second pilot operated check valve 70, the third working port A2 and the oil inlet P2 of the second direction valve 30, and the first working port A1 and the oil return port T1 of the first direction valve 20. In this manner, the piston 52 of the plunger cylinder 50 is allowed to continue to retract under load until the retracted position is reached, i.e., the positional error of the differential cylinder 40 and the piston of the plunger cylinder 50 in the retracted position is eliminated.
During the retraction process of the pistons of the differential cylinder 40 and the plunger cylinder 50, when the plunger cylinder 50 is first retracted to the retracted position, and compensation needs to be performed for the retracted position of the piston 42 of the differential cylinder 40 (i.e. the piston 42 of the differential cylinder 40 is not retracted), the first reversing valve 20 is controlled to maintain the second state, and the third working oil port A2 and the oil return port T2 of the second reversing valve 30 are controlled to be conducted. At this time, the hydraulic oil output from the oil pump 10 sequentially passes through the oil inlet P1 and the second working oil port B1 of the first reversing valve 20 and enters the control oil ports of the first hydraulic check valve 60 and the second hydraulic check valve 70. Therefore, the first pilot operated check valve 60 is reversely conducted, so that the piston of the differential cylinder 40 presses the rodless cavity 46 of the differential cylinder 40 under the load, and the hydraulic oil in the rodless cavity 46 of the differential cylinder 40 is sequentially discharged to the oil tank 100 through the first pilot operated check valve 60 and the first working oil port A1 and the oil return port T1 of the first reversing valve 20. Meanwhile, the rod cavity 44 of the differential cylinder 40 forms negative pressure, and hydraulic oil in the oil storage tank 100 is sucked into the rod cavity 44 of the differential cylinder 40 through the oil return port T2 and the third working port A2 of the second reversing valve 30 in sequence, so that the piston of the differential cylinder 40 continuously retracts until reaching the retracted position, namely, the position error of the retracted positions of the pistons of the differential cylinder 40 and the plunger cylinder 50 is eliminated.
It should be noted that, when the pistons of the differential cylinder 40 and the plunger cylinder 50 retract to the retracted position first during the retraction process, and the retracted position of the piston of the differential cylinder 40 needs to be compensated, the third working port and the oil inlet of the second reversing valve 30 may be controlled to be conducted. At this time, the hydraulic oil output from the oil pump 10 sequentially passes through the oil inlet of the first reversing valve 20 and the second working oil port B1 to enter the control oil ports of the first pilot operated check valve 60 and the second pilot operated check valve 70. Therefore, the first hydraulic check valve 60 is reversely conducted, so that the piston of the differential cylinder 40 extrudes the rodless cavity 46 of the differential cylinder 40 under the action of load, and the hydraulic oil in the rodless cavity 46 of the differential cylinder 40 sequentially passes through the first hydraulic check valve 60, the oil inlet of the second reversing valve 30 and the third working oil port A2 to enter the rod cavity 44 of the differential cylinder 40, so that the piston of the differential cylinder 40 continuously retracts until reaching the retracted position, namely, the position error of the retracted position of the pistons of the differential cylinder 40 and the plunger cylinder 50 is eliminated.
In particular embodiments, the second reversing valve 30 includes a third state and a fourth state. When the second direction valve 30 is in the third state, the third working port A2 of the second direction valve 30 communicates with the oil inlet P2, so that the rod chamber 44 of the differential cylinder 40 communicates with the first working port A1 of the first direction valve 20. In this way, the extension position of the piston 52 of the plunger cylinder 50 can be compensated for when the pistons of the differential cylinder 40 and the plunger cylinder 50 extend.
When the second direction valve 30 is in the fourth state, the third working oil port A2 of the second direction valve 30 is in communication with the oil return port T2, so that the rod chamber 44 of the differential cylinder 40 is in communication with the oil return port T2 of the second direction valve 30. In this way, the piston 42 extending position of the differential cylinder 40 can be compensated for when the pistons of the differential cylinder 40 and the plunger cylinder 50 extend.
In particular, in the embodiment, the hydraulic driving system further includes a first travel switch S1, a second travel switch S2, and a controller. The first travel switch S1 and the second travel switch S2 are electrically connected to a controller, which is electrically connected to the first reversing valve 20 and the second reversing valve 30. The first travel switch S1 and the second travel switch S2 are used to detect the extension of the pistons of the differential cylinder 40 and the plunger cylinder 50, respectively.
During the extension of the pistons of the differential cylinder 40 and the plunger cylinder 50:
when the first travel switch S1 detects that the piston 42 of the differential cylinder 40 is extended into position, and it is necessary to compensate for the extended position of the piston 52 of the plunger cylinder 50 (i.e., the piston 52 of the plunger cylinder 50 is not extended into position, and the second travel switch S2 is not triggered), the controller may control the first reversing valve 20 to maintain the first state, and control the second reversing valve 30 to be in the third state, so as to compensate for the extended position of the piston 52 of the plunger cylinder 50, thereby reducing or eliminating the positional error of the extended positions of the differential cylinder 40 and the plunger cylinder 50.
When the second travel switch S2 detects that the plunger cylinder 50 is extended into position, it is necessary to compensate for the extended position of the piston of the differential cylinder 40 (i.e., the piston 42 of the differential cylinder 40 is not extended into position, the first travel switch S1 is not triggered), the controller controls the first reversing valve 20 to maintain the first state, and controls the second reversing valve 30 to be in the fourth state, thereby compensating for the extended position of the piston 42 of the differential cylinder 40, and reducing or eliminating the positional error of the extended positions of the pistons of the differential cylinder 40 and the plunger cylinder 50.
In particular to the embodiment, the hydraulic drive system further includes a third travel switch S3 and a fourth travel switch S4. The third travel switch S3 and the fourth travel switch S4 are electrically connected to the controller, and the third travel switch S3 and the fourth travel switch S4 are respectively used for detecting the retraction situation of the pistons of the differential cylinder 40 and the plunger cylinder 50.
During piston retraction of differential cylinder 40 and plunger cylinder 50:
when the third travel switch S3 detects that the piston 42 of the differential oil cylinder 40 is retracted first, the retracted position of the piston 52 of the plunger oil cylinder 50 needs to be compensated (i.e., the piston 52 of the plunger oil cylinder 50 is not retracted, and the fourth travel switch S4 is not triggered), the controller controls the first reversing valve 20 to maintain the second state, and controls the second reversing valve 30 to be in the third state or the fourth state, so that the hydraulic oil output by the oil pump 10 continues to enter the control oil port of the second hydraulic control check valve 70 through the oil inlet P1 and the second working oil port B1 of the first reversing valve 20 in sequence, and the second hydraulic control check valve 70 is reversely conducted. Therefore, the piston 52 of the plunger cylinder 50 continues to retract under the load, and the hydraulic oil discharged from the plunger cylinder 50 is sequentially discharged through the third working port A2 and the oil return port T2 of the second direction valve 30, or the hydraulic oil discharged from the plunger cylinder 50 is sequentially discharged through the third working port A2 and the oil inlet P2 of the second direction valve 30, and the first working port A1 and the oil return port T1 of the first direction valve 20. That is, compensation for the retracted position of the piston 52 of the plunger cylinder 50 is achieved, reducing or eliminating the positional error of the retraction of the pistons of the differential cylinder 40 and the plunger cylinder 50. It should be noted that, since the differential cylinder 40 is retracted in place, the hydraulic oil in the rodless chamber 46 of the differential cylinder 40 has been drained under the pressing action of the piston 42 of the differential cylinder 40, the piston 42 of the differential cylinder 40 is not retracted any more, so that the hydraulic oil drained from the plunger cylinder 50 does not enter the rod chamber 44 of the differential cylinder 40 when compensating for the retracted position of the piston 52 of the plunger cylinder 50, but is drained through the oil return port T1 of the first direction valve 20 or the oil return port T2 of the second direction valve 30.
When the fourth travel switch S4 detects that the piston 52 of the plunger cylinder 50 is retracted in place first and compensation is required for the retracted position of the piston 42 of the differential cylinder 40, the controller controls the first reversing valve 20 to maintain the second state and controls the second reversing valve 30 to be in the third state or the fourth state, so that hydraulic oil enters the control oil port of the first pilot operated check valve 60, and the first pilot operated check valve 60 is reversely conducted, so that the piston of the differential cylinder 40 continues to retract under the action of load, and hydraulic oil in the rodless cavity 46 of the differential cylinder 40 sequentially passes through the first pilot operated check valve 60 and the first working oil port A1 of the first reversing valve 20 and is discharged from the oil return port T1 of the first reversing valve 20. Meanwhile, the rod cavity 44 of the differential cylinder 40 forms negative pressure, so that hydraulic oil is sucked in from the oil return port T2 of the second reversing valve 30 or the oil return port T1 of the first reversing valve 20 and enters the rod cavity 44 of the differential cylinder 40, and further the retracted position of the piston 42 of the differential cylinder 40 is compensated, and the position errors of the retracted positions of the pistons of the differential cylinder 40 and the plunger cylinder 50 are reduced or eliminated. It should be noted that, since the piston 52 of the plunger cylinder 50 is retracted in place, the hydraulic oil in the plunger cylinder 50 is drained under the pressing action of the piston 52 of the plunger cylinder 50, and the piston of the plunger cylinder 50 is not retracted any more. In this way, when compensating the retracted position of the differential cylinder 40, hydraulic oil enters the control port of the first hydraulic check valve 60 and also enters the control port of the second hydraulic check valve 70, so that the second hydraulic check valve 70 is also reversely conducted. However, since there is no hydraulic oil in the plunger cylinder 50, the state of the plunger cylinder 50 is not affected.
In one embodiment, the oil inlet end of the oil pump 10 is connected to the oil reservoir 100. In order to facilitate recycling of hydraulic oil, the oil inlet end of the oil pump 10, the oil return port T1 of the first reversing valve 20, the oil return port T2 of the second reversing valve 30 and the oil discharge port of the relief valve 90 are all communicated with the same oil storage tank 100 through pipelines. In other embodiments, the oil inlet end of the oil pump 10, the oil return port T1 of the first reversing valve 20, the oil return port T2 of the second reversing valve 30, and the oil drain port of the relief valve 90 may be respectively connected to different oil reservoirs through pipes, which is not limited herein.
Referring to fig. 2, it should be noted that the hydraulic compensating structure is not limited to the manner of using the second directional valve 30 in the above embodiment, but may also be other valve structures, for example, in another embodiment, the hydraulic compensating structure may include the third directional valve 32 and the fourth directional valve 34. That is, the present embodiment is different from the above-described embodiment in the hydraulic pressure compensating structure.
In the present embodiment, the third and fourth directional valves 32, 34 each have an oil inlet (P3, P4) and an oil outlet (T3, T4). The oil inlet P3 and the oil outlet T3 of the third reversing valve 32 can be controlled to be turned on or off, and the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 can be controlled to be turned on or off. The oil inlet P3 and the oil outlet T3 of the third reversing valve 32 are respectively communicated with the first working oil port A1 of the first reversing valve 20 and the oil inlet of the second hydraulic control one-way valve 70; the oil inlet P4 of the fourth reversing valve 34 is communicated between the rod cavity 44 of the differential cylinder 40 and the oil inlet of the second pilot operated check valve 70, and the oil outlet T4 of the fourth reversing valve 34 is used for communicating with the oil storage tank 100.
As such, during the piston extension actions of the differential cylinder 40 and the plunger cylinder 50:
when the piston 42 of the differential cylinder 40 first extends to a position, and compensation is required for the extending position of the piston 52 of the plunger cylinder 50 (i.e. the piston 52 of the plunger cylinder 50 does not extend to a position), the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 are controlled to be turned on, and the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 are controlled to be kept turned off. At this time, the hydraulic oil output from the oil outlet end of the oil pump 10 sequentially passes through the oil inlet P1 and the first working oil port A1 of the first reversing valve 20, the oil inlet P3 and the oil outlet T3 of the third reversing valve 32, and the second hydraulic control check valve 70, and further enters the plunger cylinder 50, so that the piston 52 of the plunger cylinder 50 continues to extend until reaching the extending position, and the extending error of the pistons of the differential cylinder 40 and the plunger cylinder 50 is reduced or eliminated.
When the piston 52 of the plunger cylinder 50 is first extended to a proper position, and the extended position of the piston 42 of the differential cylinder 40 needs to be compensated (i.e., the piston 42 of the differential cylinder 40 is not extended to a proper position), the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 may be controlled to be kept disconnected, and the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 may be controlled to be conducted, so that the hydraulic oil output from the oil outlet end of the oil pump 10 sequentially passes through the oil inlet P1 and the first working oil port A1 of the first reversing valve 20 and the first hydraulic control check valve 60, and enters the rodless cavity 46 of the differential cylinder 40, and the hydraulic oil with the rod cavity 44 of the differential cylinder 40 is discharged through the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34, i.e., the piston 42 of the differential cylinder 40 continues to extend until reaching the extended to a proper position, and the extended to a proper position error of the pistons of the differential cylinder 40 and the plunger cylinder 50 is reduced or eliminated.
During the piston retracting actions of the differential cylinder 40 and the plunger cylinder 50:
when the piston 42 of the differential cylinder 40 is first retracted, and compensation for the retracted position of the piston 52 of the plunger cylinder 50 is required (i.e., the piston 52 of the plunger cylinder 50 is not retracted), the first reversing valve 20 is controlled to maintain the second state, the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 are controlled to be disconnected, and the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 are controlled to be connected. In this way, the hydraulic oil output from the oil outlet end of the oil pump 10 enters the control oil ports of the first hydraulic check valve 60 and the second hydraulic check valve 70 through the oil inlet P1 and the second working oil port B1 of the first reversing valve 20, the first hydraulic check valve 60 and the second hydraulic check valve 70 are reversely conducted, the piston 52 of the plunger oil cylinder 50 continues to retract under the action of the load, and meanwhile, the hydraulic oil discharged from the plunger oil cylinder 50 is sequentially discharged to the oil storage tank 100 through the second hydraulic check valve 70 and the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34, so that the retraction errors of the pistons of the differential oil cylinder 40 and the plunger oil cylinder 50 are reduced or eliminated. It will be appreciated that in other embodiments, the oil inlet P3 and the oil outlet T3 of the third directional valve 32 may be controlled to be on, and the oil inlet P4 and the oil outlet T4 of the fourth directional valve 34 may be controlled to be off. At this time, the hydraulic oil discharged from the plunger cylinder 50 sequentially passes through the second pilot operated check valve 70, the oil inlet P3 and the oil outlet T3 of the third directional valve 32, and the first working oil port A1 and the oil return port T1 of the first directional valve 20, and is discharged to the oil reservoir 100.
When the piston 52 of the plunger cylinder 50 is first retracted, the retracted position of the piston 42 of the differential cylinder 40 needs to be compensated (i.e., the piston 42 of the differential cylinder 40 is not retracted), the first reversing valve 20 is controlled to maintain the second state, the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 are controlled to be disconnected, and the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 are controlled to be connected. In this way, the hydraulic oil output from the oil outlet end of the oil pump 10 enters the control oil port of the first hydraulic check valve 60 through the oil inlet P1 and the second working oil port B1 of the first reversing valve 20, so that the first hydraulic check valve 60 is reversely conducted, and the piston 42 of the differential oil cylinder 40 continues to retract under the action of the load, and the hydraulic oil in the rodless cavity 46 of the differential oil cylinder 40 is sequentially discharged through the first hydraulic check valve 60, the first working oil port A1 of the first reversing valve 20 and the oil return port T1. Meanwhile, negative pressure is formed in the rod cavity 44 of the differential cylinder 40, so that hydraulic oil is sucked from the oil outlet T4 of the fourth reversing valve 34 and enters the rod cavity 44 of the differential cylinder 40 through the oil inlet P4 of the fourth reversing valve 34, namely, the piston 42 of the differential cylinder 40 continues to retract until reaching the retracted position, and the retraction errors of the pistons of the differential cylinder 40 and the plunger cylinder 50 are reduced or eliminated. It will be appreciated that in other embodiments, the oil inlet P3 and the oil outlet T3 of the third directional valve 32 may be controlled to be on, and the oil inlet P4 and the oil outlet T4 of the fourth directional valve 34 may be controlled to be off. At this time, the hydraulic oil discharged from the rodless chamber 46 of the differential cylinder 40 sequentially passes through the first pilot operated check valve 60, the oil outlet T3 and the oil inlet P3 of the third directional valve 32, and thus enters the rod chamber 44 of the differential cylinder 40.
In particular, in the embodiment, the hydraulic driving system further includes a first travel switch S1, a second travel switch S2, and a controller. The first travel switch S1 and the second travel switch S2 are electrically connected to the controller. The controller is electrically connected to the first reversing valve 20 and the second reversing valve 30. The first travel switch S1 and the second travel switch S2 are used to detect the extension of the differential cylinder 40 and the plunger cylinder 50, respectively.
During the piston extension actions of the differential cylinder 40 and the plunger cylinder 50:
when the first travel switch S1 detects that the piston 42 of the differential oil cylinder 40 first extends to a position, compensation needs to be performed on the extending position of the piston 52 of the plunger oil cylinder 50 (i.e., the second travel switch S2 does not detect that the piston of the plunger oil cylinder 50 extends to a position), the controller controls the first reversing valve 20 to maintain the first state, and controls the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 to be conducted, and the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 to be disconnected, so that the hydraulic oil output from the oil outlet end of the oil pump 10 sequentially passes through the oil inlet P1 and the first working oil port A1 of the first reversing valve 20, the oil inlet P3 and the oil outlet T3 of the third reversing valve 32, and the second hydraulic control one-way valve 70, and the piston 52 of the plunger oil cylinder 50 is driven by the entering the plunger oil cylinder 50 to continue extending until reaching the extending position (i.e., the second travel switch S2 is triggered), and the position error of the extending position of the differential oil cylinder 40 and the piston of the plunger oil cylinder 50 is reduced or eliminated.
When the second travel switch S2 detects that the piston 52 of the plunger cylinder 50 is first extended to a proper position, it is necessary to compensate for the extended position of the piston 42 of the differential cylinder 40 (the differential cylinder 40 is not extended to a proper position, i.e., the first travel switch S1 is not triggered), the controller controls the first reversing valve 20 to maintain the first state, and controls the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 to maintain disconnected, and controls the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 to be conducted, so that the rodless chamber 46 of the differential cylinder 40 continues to be filled with hydraulic oil, and the hydraulic oil with the rod chamber 44 continues to be discharged, so that the piston of the differential cylinder 40 continues to be extended until reaching the extended position (i.e., the first travel switch S1 is triggered), i.e., the positional error of the extended positions of the differential cylinder 40 and the piston of the plunger cylinder 50 is reduced or eliminated.
In particular embodiments, the hydraulic drive system further includes a third travel switch S3 and a fourth travel switch S4, where the third travel switch S3 and the fourth travel switch S4 are electrically connected to the controller. The third and fourth travel switches S3 and S4 are used to detect the piston retraction situations of the differential cylinder 40 and the plunger cylinder 50, respectively.
During the piston retracting actions of the differential cylinder 40 and the plunger cylinder 50:
When the third travel switch S3 detects that the piston 42 of the differential cylinder 40 is first retracted, the retracted position of the piston 52 of the plunger cylinder 50 needs to be compensated (i.e., the plunger cylinder 50 is not retracted, and the fourth travel switch S4 is not triggered), the first reversing valve 20 is controlled to maintain the second state, and the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 or the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 are controlled to be conducted, so that hydraulic oil in the plunger cylinder 50 is continuously discharged, i.e., the piston 52 of the plunger cylinder 50 is continuously retracted until reaching the retracted position (i.e., the fourth travel switch S4 is triggered), thereby reducing or eliminating the positional error of the differential cylinder 40 and the piston of the plunger cylinder 50 in the retracted position.
When the fourth travel switch S4 detects that the piston of the plunger cylinder 50 is retracted first, and the retraction position of the piston of the differential cylinder 40 needs to be compensated (the differential cylinder 40 is not retracted in place, and the third travel switch S3 is not triggered), the first reversing valve 20 is controlled to maintain the second state, the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 are kept disconnected, the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 are conducted, the piston 42 of the differential cylinder 40 continues to retract under the action of load, and hydraulic oil in the rodless cavity 46 of the differential cylinder 40 is sequentially discharged through the first hydraulic control one-way valve 60, the first working oil port A1 and the oil return port T1 of the first reversing valve 20. Meanwhile, the rod cavity 44 of the differential cylinder 40 forms negative pressure, and hydraulic oil is sequentially sucked into the rod cavity 44 of the differential cylinder 40 through the oil outlet T4 and the oil inlet P4 of the fourth reversing valve 34. That is, the piston 42 of the differential cylinder 40 continues to retract until the retracted position is reached (the third stroke switch S3 is triggered), thereby reducing or eliminating the positional error of the pistons of the differential cylinder 40 and the plunger cylinder 50 in the retracted position.
When compensating the retracted position of the piston of the differential cylinder 40, the first reversing valve 20 may be controlled to maintain the second state, the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 are turned on, and the oil inlet P4 and the oil outlet T4 of the fourth reversing valve 34 are turned off. The piston 42 of the differential cylinder 40 continues to retract under the load, the hydraulic oil in the rodless chamber 46 of the differential cylinder 40 sequentially passes through the first pilot operated check valve 60, and the hydraulic oil discharged from the rodless chamber 46 of the differential cylinder 40 continues to enter the rod-shaped chamber 44 of the differential cylinder 40 through the oil inlet P3 and the oil outlet T3 of the third reversing valve 32 due to the negative pressure formed in the differential cylinder 40. In this way, it is also possible to achieve continued retraction of the pistons of the differential cylinder 40 until the retracted position is reached (the third stroke switch S3 is triggered), thereby reducing or eliminating the positional error of the pistons of the differential cylinder 40 and the plunger cylinder 50 in the retracted position.
In order to facilitate recycling of hydraulic oil, the oil outlet T4 of the fourth reversing valve 34 and the oil inlet end of the oil pump 10 are connected to the same oil reservoir 100 through a pipe. In other embodiments, the oil outlet T4 of the fourth reversing valve 34 and the oil inlet end of the oil pump 10 may also be respectively connected to different oil tanks through pipes, which is not limited herein.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (6)
1. The hydraulic driving system is characterized by comprising an oil pump, a first reversing valve, a differential oil cylinder, a plunger oil cylinder, a hydraulic compensation structure, a first hydraulic control one-way valve and a second hydraulic control one-way valve; the differential oil cylinder is provided with a rod cavity and a rodless cavity;
the oil outlet end of the oil pump is communicated with the oil inlet of the first reversing valve, the first working oil port of the first reversing valve is communicated with the rodless cavity of the differential oil cylinder, and the rod cavity of the differential oil cylinder is communicated with the plunger oil cylinder through pipelines; the oil return port of the first reversing valve is used for communicating with an oil storage tank;
The hydraulic compensation structure is used for controllably enabling a rod cavity of the differential oil cylinder to be communicated with a first working oil port of the first reversing valve or enabling the plunger oil cylinder to be communicated with an oil storage tank;
the first hydraulic control one-way valve and the second hydraulic control one-way valve are respectively provided with an oil inlet, an oil outlet and a control oil port;
the first hydraulic control one-way valve is arranged between the first reversing valve and the differential cylinder, an oil inlet of the first hydraulic control one-way valve is communicated with a first working oil port of the first reversing valve, and an oil outlet of the first hydraulic control one-way valve is communicated with a rodless cavity of the differential cylinder;
the second hydraulic control one-way valve is arranged between the differential oil cylinder and the plunger oil cylinder, an oil inlet of the second hydraulic control one-way valve is communicated with a rod cavity of the differential oil cylinder, and an oil outlet of the second hydraulic control one-way valve is communicated with the plunger oil cylinder;
the control oil ports of the first hydraulic control one-way valve and the second hydraulic control one-way valve are communicated with the second working oil port of the first reversing valve;
the first reversing valve comprises a first state and a second state;
when the first reversing valve is in the first state, an oil inlet of the first reversing valve is communicated with a first working oil port, and a second working oil port of the first reversing valve is communicated with an oil return port;
When the first reversing valve is in the second state, an oil inlet of the first reversing valve is communicated with a second working oil port, and a first working oil port of the first reversing valve is communicated with an oil return port;
the hydraulic compensation structure comprises a second reversing valve, wherein the second reversing valve is provided with an oil inlet, a third working oil port and an oil return port;
the oil inlet of the second reversing valve is communicated with the first working oil port of the first reversing valve, the third working oil port of the second reversing valve is communicated with the rod cavity of the differential oil cylinder and the oil inlet of the second hydraulic control one-way valve, and the oil return port of the second reversing valve is used for communicating an oil storage tank;
the hydraulic compensation structure also comprises a third reversing valve and a fourth reversing valve; the third reversing valve and the fourth reversing valve are respectively provided with an oil inlet and an oil outlet; the oil inlet and the oil outlet of the third reversing valve can be controlled to be connected or disconnected, and the oil inlet and the oil outlet of the fourth reversing valve can be controlled to be connected or disconnected;
the oil inlet and the oil outlet of the third reversing valve are respectively communicated with the first working oil port of the first reversing valve and the oil inlet of the second hydraulic control one-way valve; the oil inlet of the fourth reversing valve is communicated between the rod cavity of the differential oil cylinder and the oil inlet of the second hydraulic control one-way valve, and the oil outlet of the fourth reversing valve is used for communicating an oil storage tank.
2. The hydraulic drive system of claim 1, wherein the second reversing valve includes a third state and a fourth state;
when the second reversing valve is in the third state, a third working oil port of the second reversing valve is communicated with the oil inlet;
when the second reversing valve is in the fourth state, the third working oil port of the second reversing valve is communicated with the oil return port.
3. The hydraulic drive system of claim 2, further comprising a first travel switch, a second travel switch, and a controller; the first travel switch and the second travel switch are electrically connected to the controller; the controller is electrically connected with the first reversing valve and the second reversing valve;
the first travel switch and the second travel switch are respectively used for detecting the extending-out situation of the differential oil cylinder and the plunger oil cylinder;
during the extending action of the differential oil cylinder and the plunger oil cylinder: when the first travel switch detects that the differential oil cylinder stretches out to the position, the controller controls the first reversing valve to keep the first state, and the second reversing valve is in the third state; or when the second travel switch detects that the plunger oil cylinder stretches out to the position, the controller controls the first reversing valve to keep the first state, and the second reversing valve is in the fourth state.
4. The hydraulic drive system of claim 1, further comprising a first travel switch, a second travel switch, and a controller, the first travel switch and the second travel switch being electrically connected to the controller, the controller being electrically connected to the first reversing valve and the second reversing valve;
the first travel switch and the second travel switch are respectively used for detecting the extending-out situation of the differential oil cylinder and the plunger oil cylinder;
during the extending action of the differential oil cylinder and the plunger oil cylinder: when the first travel switch detects that the differential oil cylinder stretches out to the position, the controller controls the first reversing valve to keep the first state, the oil inlet and the oil outlet of the third reversing valve are communicated, and the oil inlet and the oil outlet of the fourth reversing valve are disconnected; or when the second travel switch detects that the plunger oil cylinder stretches out to the position, the controller controls the first reversing valve to keep the first state, the oil inlet and the oil outlet of the third reversing valve are disconnected, and the oil inlet and the oil outlet of the fourth reversing valve are connected.
5. The hydraulic drive system of claim 1, further comprising a one-way throttle valve in communication with the first working port of the first reversing valve and the oil inlet of the first pilot operated one-way valve.
6. The hydraulic drive system of claim 1, further comprising a relief valve having an oil inlet and an oil outlet, the oil inlet of the relief valve being in communication with the oil outlet of the oil pump.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910916730.9A CN110566527B (en) | 2019-09-26 | 2019-09-26 | Hydraulic drive system |
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| CN201910916730.9A CN110566527B (en) | 2019-09-26 | 2019-09-26 | Hydraulic drive system |
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| CN110566527A CN110566527A (en) | 2019-12-13 |
| CN110566527B true CN110566527B (en) | 2024-04-16 |
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| CN201910916730.9A Active CN110566527B (en) | 2019-09-26 | 2019-09-26 | Hydraulic drive system |
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| CN111056334B (en) * | 2019-12-31 | 2021-10-22 | 龙合智能装备制造有限公司 | Self-adaptive loading platform for integral loading of container |
| CN117072394B (en) * | 2023-08-11 | 2024-04-12 | 湖北盛达动力科技有限公司 | Manual pump and vehicle hydraulic system comprising same |
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| WO2013037198A1 (en) * | 2011-09-14 | 2013-03-21 | 徐州重型机械有限公司 | Water plunger pump and hydraulic control system thereof |
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| CN109879184A (en) * | 2019-03-06 | 2019-06-14 | 三一汽车起重机械有限公司 | Counterweight synchronization hydraulic system and crane |
| CN209041205U (en) * | 2018-10-15 | 2019-06-28 | 六安远大住宅工业有限公司 | For controlling the fluid power system and roll-over table of roll-over table flip-arm |
| CN211039191U (en) * | 2019-09-26 | 2020-07-17 | 长沙远大住宅工业集团股份有限公司 | Hydraulic drive system |
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| JPH07167109A (en) * | 1993-10-20 | 1995-07-04 | Kobe Steel Ltd | Hydraulic control valve and hydraulic cylinder circuit |
| WO2013037198A1 (en) * | 2011-09-14 | 2013-03-21 | 徐州重型机械有限公司 | Water plunger pump and hydraulic control system thereof |
| WO2015078249A1 (en) * | 2013-11-26 | 2015-06-04 | 三一汽车制造有限公司 | Integrated hydraulic valve unit, hydraulic driving system and concrete pump |
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| CN109879184A (en) * | 2019-03-06 | 2019-06-14 | 三一汽车起重机械有限公司 | Counterweight synchronization hydraulic system and crane |
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| CN110566527A (en) | 2019-12-13 |
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