CN108561362B - Balance valve, hydraulic lifting system and operation machine - Google Patents
Balance valve, hydraulic lifting system and operation machine Download PDFInfo
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- CN108561362B CN108561362B CN201810705466.XA CN201810705466A CN108561362B CN 108561362 B CN108561362 B CN 108561362B CN 201810705466 A CN201810705466 A CN 201810705466A CN 108561362 B CN108561362 B CN 108561362B
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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
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/023—Excess flow valves, e.g. for locking cylinders in case of hose burst
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
- B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
- B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
- B66F9/075—Constructional features or details
- B66F9/20—Means for actuating or controlling masts, platforms, or forks
- B66F9/22—Hydraulic devices or systems
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Abstract
The invention relates to a balance valve, which aims to solve the problem that a hydraulic system impacts and shakes when falling back in the existing lifting hydraulic system; the balance valve is characterized by comprising a forward oil inlet, a forward oil outlet and an oil return port, and comprises a hydraulic control valve, a differential pressure control oil way and a hydraulic control valve reverse conduction control oil way; the differential pressure control oil way comprises a first electromagnetic switch valve and a first throttle valve which are sequentially connected in series from the forward oil outlet to the forward oil inlet; the hydraulic control valve reverse conduction control oil path comprises an oil inlet end and a second throttling valve connected with the self-forward oil outlet, and a second electromagnetic switch valve and a differential pressure control switch valve which are connected in series are arranged on the oil path between the oil outlet end of the second throttling valve and the oil return port; the hydraulic control end of the hydraulic control valve is connected with the oil outlet end of the second throttling valve, and the hydraulic control ends at the two ends of the differential pressure control switch valve are respectively connected with the oil inlet end and the oil outlet end of the first throttling valve; in the invention, the hydraulic control valve has no impact when being opened reversely, and improves the stability when being conducted reversely.
Description
Technical Field
The present disclosure relates to hydraulic components, and more particularly, to a counterbalance valve and hydraulic lift system and work machine.
Background
The balance valve is applied to various engineering machines, and particularly, the balance valve is most widely applied to mechanical equipment with a lifting function. The balance valve is used for preventing the working component from descending at an overspeed due to self weight or preventing the unstable movement of speed runaway caused by self weight in descending movement, thereby avoiding the occurrence of unexpected danger.
The existing balance valve is provided with a forward oil inlet, a forward oil outlet and a hydraulic control oil port; a check valve and a switch valve are connected in parallel between the forward oil inlet and the forward oil outlet, a hydraulic control end of the switch valve is connected with a hydraulic control oil port, and the check valve is communicated from the forward oil inlet to the forward oil outlet in a one-way mode. The balance valve is applied as shown in figure 1 and connected to the rodless cavity oil path of the hydraulic oil cylinder, and the hydraulic control end is connected to the rod cavity oil path of the hydraulic oil cylinder. When the hydraulic cylinder is lifted, hydraulic oil enters a rodless cavity of the hydraulic cylinder through a forward oil inlet, a one-way valve and a forward oil outlet of the balance valve, and a piston rod is pushed out to realize the lifting action; when the lifting device performs a falling action, when an object to be lifted falls back at a normal speed, the piston rod of the hydraulic oil cylinder also retracts at a normal speed, a certain pressure is arranged in the rod cavity of the hydraulic oil cylinder at the moment, and acts on the hydraulic control end of the switch valve to switch on the switch valve, so that the balance valve is switched on in a reverse direction, namely, hydraulic oil flows out through the rodless cavity of the hydraulic oil cylinder, the forward oil outlet of the balance valve, the switch valve and the forward oil inlet, and the retraction of the piston rod of the hydraulic oil cylinder is realized. When the lifted object descends at an excessively fast speed under the action of self weight, the pressure of a rod cavity of the hydraulic oil cylinder is too low (the piston of the hydraulic oil cylinder retracts excessively fast, the rod cavity is possibly vacuumed to be in a negative pressure state), the pressure of the rod cavity is not enough to enable the switch valve to be switched on, so that the balance valve is in a cut-off state, hydraulic oil in a rodless cavity of the hydraulic oil cylinder cannot flow back through the balance valve, and the retraction speed of the piston rod of the hydraulic oil cylinder is limited.
In the application of the balance valve, when the lifted object falls back, the forward oil outlet has certain pressure and acts on the valve port of the switch valve, and when the switch valve is conducted reversely, the opening starting time of the switch valve is short, the starting speed is high, and the phenomena of impact and shaking are easily caused when the switch valve is descended and opened.
Disclosure of Invention
The invention aims to solve the technical problem of impact shake of a hydraulic system during falling back in the existing lifting hydraulic system, and provides a balance valve, the hydraulic lifting system and an operating machine, so that the problem of impact shake of the system during falling back of a lifting heavy object is avoided.
The technical scheme for realizing the purpose of the invention is as follows: the balance valve is characterized by comprising a forward oil inlet, a forward oil outlet and an oil return port, and a hydraulic control valve, wherein a differential pressure control oil path connected with the hydraulic control valve in parallel is arranged between the forward oil inlet and the forward oil outlet, and a hydraulic control valve reverse conduction control oil path is arranged between the forward oil inlet and the oil return port;
the hydraulic control valve is connected between the forward oil inlet and the forward oil outlet, the hydraulic control valve is conducted in the forward direction when the forward oil inlet is filled with oil, the forward oil outlet is filled with oil in the reverse direction, and the acting force of the hydraulic oil in an oil cavity where the hydraulic control valve is connected with the forward oil outlet, which acts on the valve core of the hydraulic control valve, is greater than the acting force of the spring at the hydraulic control end of the hydraulic control valve and the acting force of the hydraulic oil on the valve core, and the hydraulic control valve is conducted in;
the differential pressure control oil way comprises a first electromagnetic switch valve and a first throttling valve which are sequentially connected in series from a forward oil outlet to a forward oil inlet;
the hydraulic control valve reverse conduction control oil path comprises an oil inlet end and a second throttling valve connected with the self-forward oil outlet, and a second electromagnetic switch valve and a differential pressure control switch valve which are connected in series are arranged on the oil path between the oil outlet end of the second throttling valve and the oil return port;
the hydraulic control ends of the hydraulic control valve are connected with the oil outlet end of the second throttling valve, and the hydraulic control ends of the two ends of the differential pressure control switch valve are respectively connected with the oil inlet end and the oil outlet end of the first throttling valve;
the first electromagnetic switch valve and the second electromagnetic switch valve are in a cut-off state normally; the normal state of the differential pressure control switch valve is a conduction state, and the differential pressure control switch valve is in a cut-off state when the acting force of the differential pressure at the two ends of the first throttle valve at the two ends of the valve core of the differential pressure control switch valve is greater than the spring force acting on the valve core of the differential pressure control switch valve.
In the invention, the reverse conduction of the hydraulic control valve is not controlled by an external pressure signal, but is controlled by the pressure difference generated at two ends of the first throttle valve in the pressure difference control oil way during the reverse conduction, when the flow rate of the reverse conduction is overlarge (the falling speed of the lifted object is too high), the pressure difference generated at two ends of the first throttle valve in the pressure difference control oil way enables the pressure difference control switch valve to be closed, so that the pressure at the hydraulic control end of the hydraulic control valve is equal to the pressure at the forward oil outlet, the hydraulic control valve is closed, and the falling speed of the lifted object is prevented from exceeding the designed value. When the hydraulic control valve is reversely conducted, a certain pressure is arranged at the forward oil outlet, but before the hydraulic control valve is reversely conducted, hydraulic oil of the forward oil outlet flows into an oil tank loop through the second throttling valve, the second electromagnetic switch valve, the differential pressure control switch valve and the fourth throttling valve, so that the hydraulic control valve is free of impact when opened, and the stability of the hydraulic control valve during reverse conduction is improved.
In the above balance valve, the differential pressure control oil path further includes a third throttle valve disposed between the forward oil outlet and the first throttle valve and connected in series with the first electromagnetic switch valve, and the first throttle valve may be connected to one side of an oil inlet end of the first electromagnetic switch valve or disposed to one side of an oil outlet end of the first electromagnetic switch valve.
In the balance valve, a fourth throttle valve is further arranged in series between the second throttle valve and the oil return port on the hydraulic control valve reverse conduction control oil path. The fourth throttle valve can be arranged at any position of the oil outlet end of the second throttle valve, namely the fourth throttle valve, the second electromagnetic switch valve and the differential pressure control switch valve are arranged in series in any sequence.
In the balance valve, a two-way stop valve is arranged between the oil inlet end and the oil outlet end of the first electromagnetic switch valve when the first electromagnetic switch valve is in a stop state. And a one-way valve is arranged between the oil inlet end and the oil outlet end of the second electromagnetic switch valve when the second electromagnetic switch valve is in a cut-off state. The two-way stop valve is arranged in the stop position of the first electromagnetic switch valve, and the check valve is arranged in the stop position of the second electromagnetic switch valve, so that the leakage amount of the electromagnetic switch valve in the stop position is reduced.
The technical scheme for realizing the purpose of the invention is as follows: provides a lifting hydraulic system, which comprises a lifting oil cylinder, a lifting oil cylinder control valve, a lifting control device for controlling the lifting oil cylinder control valve, a lifting operation detection device for detecting the lifting operation of the lifting control device, it is characterized by also comprising a controller, a lifting operation detection device which is connected with the controller and is used for detecting the lifting operation of the lifting control device, and the balance valve, a positive oil inlet and a positive oil outlet of the balance valve are connected in series on an oil way between the lifting oil cylinder control valve and the lifting cavity of the lifting oil cylinder, the oil return port of the balance valve is connected with an oil tank loop, the electromagnetic ends of the first electromagnetic switch valve and the second electromagnetic switch valve of the balance valve are connected with the controller, when the lifting operation detection device detects that the lifting control device performs a falling operation, the controller outputs a controller signal to enable the second electromagnetic switch valve to be in a conducting state firstly and then enable the first electromagnetic switch to be in a conducting state. In the invention, when the lifted object falls back, after the controller detects that the lifting control device performs the operation of falling back of the lifted object through the lifting operation detection device, the controller firstly outputs a control signal to the second electromagnetic switch valve to enable the second electromagnetic switch valve to be in a conduction position, an oil path from the forward oil outlet to the oil return port is conducted, and the hydraulic control end of the hydraulic control valve is reduced in pressure under the action of the second throttle valve to enable the hydraulic control valve to be opened, so that the balance valve is conducted in a reverse direction (the forward oil outlet is conducted to the forward oil inlet). The controller then places the first electromagnetic switch valve in the conducting position. When the valve is reversely conducted, the flow rate from the forward oil outlet to the forward oil inlet is in a designed value range (namely the falling speed of the lifted object is in a designed safety value range), the pressure difference from the forward oil outlet to the forward oil inlet is small, the pressure difference at two ends of the first throttle valve is not enough to push the pressure difference control switch valve to change the direction from the conducting position to the stopping position, and the balance valve is normally reversely conducted. When the falling speed of the lifted object exceeds a designed value, the pressure difference between the forward oil outlet and the forward oil inlet is increased, the pressure difference generated at the two ends of the first throttling valve is enough to push the pressure difference control switch valve to change from a conducting position to a stopping position, after the pressure difference control switch valve is stopped, the pressure of the hydraulic control end of the hydraulic control valve is increased to close the hydraulic control valve, the hydraulic control valve is conducted in the reverse direction and stopped, and the hydraulic oil at the forward oil outlet of the balance valve can only flow out of the forward oil inlet through the pressure difference control oil path. In the invention, when the hydraulic control valve is conducted reversely, before the hydraulic control valve is conducted reversely and opened, the hydraulic oil at the forward oil outlet is decompressed to the oil tank loop through the reverse conducting control oil circuit of the hydraulic control valve, so that the impact when the hydraulic control valve is opened is avoided. Thereby making the whole hydraulic system operate smoothly.
In the invention, the lifting cavity of the hydraulic oil cylinder refers to that when the oil cavity is filled with oil, the hydraulic oil cylinder lifts and lifts a lifted object, and when the lifted object falls back, the oil cavity discharges the oil in the oil cavity. The lifting cavity can be a rodless cavity of a hydraulic oil cylinder, such as a movable arm oil cylinder of a loader, a movable arm oil cylinder of an excavator, a suspension arm lifting oil cylinder of a crane or a front crane, and a bucket lifting oil cylinder of a mining dump truck; the lifting cavity can also be a rod cavity of a hydraulic oil cylinder, for example, a bucket rod oil cylinder of an excavator, when the rod cavity of the bucket rod oil cylinder is filled with oil, the bucket rod swings forwards to lift, and when the bucket rod swings backwards under the action of gravity, the rod cavity of the bucket rod oil cylinder discharges the hydraulic oil.
The technical scheme for realizing the purpose of the invention is as follows: a working device is provided having the aforementioned balancing valve or having the aforementioned lifting hydraulic system. For example, the operation equipment can be a mining dump truck, and the lifting hydraulic system is a bucket lifting hydraulic system for lifting a bucket to tip and discharge; or the working equipment is a loader, and the lifting hydraulic system is a movable arm lifting hydraulic system; or the working equipment is an excavator, and the lifting hydraulic system is a movable arm lifting hydraulic system; or the operation equipment is a forklift, and the lifting hydraulic system is a fork lifting hydraulic system; or the operation equipment is a crane or a front crane, and the lifting hydraulic system is a boom lifting hydraulic system.
Compared with the prior art, in the balance valve, when the balance valve is conducted reversely, the reverse opening of the hydraulic control valve is controlled according to the pressure difference generated when the hydraulic control valve flows through without using an external pressure signal, and the hydraulic impact of the hydraulic control valve is small and the system is stable in the change process of the reverse opening and the stop of the hydraulic control valve.
Drawings
FIG. 1 is a schematic diagram of the lifting hydraulic system of the present invention.
Part names and serial numbers in the figure:
the hydraulic control system comprises a hydraulic oil tank 1, an oil pump 2, a pressure sensor 3, a lifting oil cylinder control valve 4, a pilot valve 5, a balance valve 6, a hydraulic control valve 61, a first electromagnetic switch valve 62, a second electromagnetic switch valve 63, a differential pressure control switch valve 64, a third throttle valve 65, a first throttle valve 66, a second throttle valve 67, a fourth throttle valve 68, a lifting oil cylinder 7 and a controller 8.
Detailed Description
The following description of the embodiments refers to the accompanying drawings.
The lifting hydraulic system in this embodiment may be a loader boom lifting hydraulic system, an excavator boom hydraulic system, a bucket lifting hydraulic system of a mining dump truck, a boom lifting hydraulic system of a crane, or a fork lifting hydraulic system of a forklift, and may also be a bucket rod back-and-forth swing hydraulic system of an excavator, or the like, if the connection oil paths of the rod chamber and the rodless chamber of the hydraulic cylinder are interchanged. The lifting hydraulic system can be used for a hydraulic system for lifting a heavy object G by the extension and contraction of a hydraulic oil cylinder.
As shown in fig. 1, the hydraulic lifting system in this embodiment includes a lifting cylinder 7, a lifting cylinder control valve 4, a lifting control device for controlling the lifting cylinder control valve, a lifting operation detection device for detecting a lifting operation of the lifting control device, a controller 8, a lifting operation detection device connected to the controller for detecting a lifting operation of the lifting control device, and a balance valve 6.
As shown in fig. 1, the balance valve 6 has a forward oil inlet P, a forward oil outlet a, and an oil return port T, and includes a hydraulic control valve 61, a differential pressure control oil path connected in parallel with the hydraulic control valve 61 is provided between the forward oil inlet P and the forward oil outlet a, and a hydraulic control valve reverse conduction control oil path is provided between the forward oil inlet and the oil return port.
The hydraulic control valve 61 is connected between the forward oil inlet P and the forward oil outlet A, when the forward oil inlet P is filled with oil, the hydraulic control valve 61 is conducted in the forward direction, and hydraulic oil flows in from the forward oil inlet P and flows out from the forward oil outlet A through the hydraulic control valve. When the forward oil outlet is filled with oil in the reverse direction and the acting force of the hydraulic oil pressure in the oil cavity, connected with the forward oil outlet, of the hydraulic control valve 61 on the valve core of the hydraulic control valve is larger than the acting force of the hydraulic control end spring of the hydraulic control valve and the acting force of the hydraulic oil on the valve core, the hydraulic control valve is conducted in the reverse direction, namely the hydraulic oil flows in from the forward oil outlet A and flows out from the forward oil outlet through the hydraulic control valve.
In this embodiment, the differential pressure control oil path includes a first electromagnetic switch valve 62 and a first throttle valve 66 connected in series in sequence from the forward oil outlet a to the forward oil inlet P. A third throttle valve 65 connected in series with the first electromagnetic switching valve 62 may also be added between the first electromagnetic switching valve 62 and the forward oil outlet a.
In this embodiment, the hydraulic control valve reverse conduction control oil path includes an oil inlet end and a second throttle valve 67 connected to the self-forward oil outlet a, and a second electromagnetic switch valve 63 and a differential pressure control switch valve 64 connected in series are provided on the oil path between the oil outlet end of the second throttle valve 67 and the oil return port T. The second electromagnetic opening/closing valve 63 and the differential pressure control opening/closing valve 64 may be connected in series and then may be connected via a fourth throttle valve 68 and a return port T.
The hydraulic control end of the hydraulic control valve 61 is connected with the oil outlet end of the second throttle valve 67, and the hydraulic control ends of the two ends of the differential pressure control switch valve 64 are respectively connected with the oil inlet end g and the oil outlet end d of the first throttle valve 66.
The first electromagnetic switching valve 62 and the second electromagnetic switching valve 63 are both in an off state in a normal state; the pressure difference control switch valve 64 is normally in an on state, and the pressure difference control switch valve 64 is in an off state when the acting force of the pressure difference across the first throttle 66 generated across the spool of the pressure difference control switch valve 64 is greater than the spring force acting on the spool of the pressure difference control switch valve 64.
The electromagnetic control ends of the first electromagnetic switch valve 62 and the second electromagnetic switch valve 63 are connected with the controller 8, and the controller 8 outputs control signals to change the working states of the first electromagnetic switch valve and the second electromagnetic switch valve.
In this embodiment, the lift control device comprises an operation handle and a pilot valve 5 linked with the operation handle, two pilot output ends of the pilot valve 5 are connected with a hydraulic control end of a lift cylinder control valve, when the operation handle performs a lift operation, a lift pilot pressure output end of the pilot valve outputs a pilot pressure signal to act on the lift pilot control end of the lift cylinder control valve 4, an oil pump 2 sucks hydraulic oil from a hydraulic oil tank 1, the hydraulic oil is pumped out from a pump port and flows into a forward oil inlet of a balance valve through the lift cylinder control valve 4, when the operation handle performs a fallback operation, a fallback pilot pressure output end of the pilot valve outputs a pilot pressure signal to act on a fallback pilot control end of the lift cylinder control valve 4, the lift cylinder control valve 4 is reversed, and hydraulic oil in a lift cavity of the lift cylinder flows back to the hydraulic oil tank 1 through the balance valve, the lift cylinder control valve 4 and an oil tank loop.
In this embodiment, the lift operation detecting means is a pressure sensor 3 connected to the controller, and the pressure sensor 3 is disposed on an oil path between the fall pilot pressure output terminal of the pilot valve 5 and the fall pilot control terminal of the lift cylinder control valve 4, and is configured to detect a fall pilot pressure value, and if the fall pilot pressure value is greater than a preset value, it is determined that a fall operation has been performed. In other embodiments, the lifting operation detection device may also be different according to different control systems, for example, when the operation handle is an electrically controlled operation handle, the operation handle directly outputs a corresponding electrical signal when the operation handle is operated, at this time, the lifting operation detection device may be the operation handle itself, and the controller acquires a signal of the fall back signal output end from the operation handle, so as to determine whether to perform the fall back operation. The lift operation detecting means may be another sensor for detecting a physical quantity related to the lift control means or the lift cylinder control valve or the lift cylinder when the lowering operation is performed, and determining whether the lift control means is performing the lift operation.
In this embodiment, when lifting, since the pressure of the forward oil inlet of the balance valve is greater than the pressure of the forward oil outlet, the hydraulic control valve is turned on in the forward direction, hydraulic oil enters from the forward oil inlet of the balance valve, flows out from the forward oil outlet a through the hydraulic control valve, enters the lifting cavity of the hydraulic oil cylinder, and pushes the piston to lift the weight.
When the controller detects the falling operation through the lifting operation detection device, the controller outputs a control signal firstly to enable the second electromagnetic switch valve to be conducted, the hydraulic control valve is conducted in the reverse direction to control the oil way to be conducted, and the pressure of the hydraulic control end of the hydraulic control valve is lower than that of the forward oil outlet due to the action of the second throttle valve. The acting force of the pressure in the oil cavity, connected with the forward oil outlet, of the hydraulic control valve on the valve core of the hydraulic control valve is larger than the elastic force of the spring in the hydraulic control cavity of the hydraulic control valve and the acting force of the hydraulic oil on the valve core, so that the hydraulic control valve is conducted, the balance valve is conducted reversely, and the hydraulic oil in the lifting cavity of the hydraulic oil cylinder flows out of the forward oil inlet of the balance valve through the forward oil outlet of the balance valve and the hydraulic control valve, enters the control valve of the lifting oil cylinder and finally enters an oil tank loop. The controller outputs an electric signal to the first electromagnetic switch valve after the second electromagnetic switch valve is switched on, so that the second electromagnetic switch valve is switched on. After the second electromagnetic switch valve is conducted, the pressure difference between the forward oil outlet and the forward oil inlet is equal to the sum of the pressure difference at the two ends of the third throttle valve and the pressure difference at the two ends of the first throttle valve. When the lifted object G falls back normally, the pressure difference between the forward oil outlet and the forward oil inlet is small, and the pressure difference shared between the two ends of the first throttling valve is not enough to enable the pressure difference control switch valve to be reversed and cut off, so that the hydraulic control valve still keeps reverse opening. When the lifting heavy object G descends at an excessively high speed under the action of the gravity of the lifting heavy object G, the pressure difference between the forward oil outlet and the forward oil inlet is large, the pressure difference shared between the two ends of the first throttling valve is large enough to enable the pressure difference control switch valve to be reversed and cut off, the hydraulic control valve is conducted reversely to control the oil way to be cut off, the pressure of the hydraulic control end of the hydraulic control valve is increased to enable the hydraulic control valve to be cut off, the flow of hydraulic oil flowing out of the lifting cavity of the lifting oil cylinder is reduced due to the fact that a main oil way flowing through the hydraulic control valve is cut off, and the falling speed of the. After the hydraulic control valve is cut off, the hydraulic oil in the lifting cavity of the lifting oil cylinder can only return to the hydraulic oil tank through the forward oil outlet A, the third throttle valve 65, the first electromagnetic switch valve 62, the first throttle valve 66, the forward oil inlet P and the lifting oil cylinder control valve 4, and due to the damping effect of the third throttle valve and the first throttle valve, the flow rate is very small, and the retraction (or extension) speed of the lifting oil cylinder is very low. If the operator wants to extend or retract the lift cylinder normally, the operator needs to first perform the operation of returning the control valve 4 of the lift cylinder to the neutral position, i.e. the first electromagnetic switch valve and the second electromagnetic switch valve are powered off and return to the cut-off position, and then operate the control valve 4 of the lift cylinder to make it work at the fall-back working position, so that the hydraulic control valve works at the reverse conducting position.
In the invention, when the hydraulic control valve is in reverse conduction, before the hydraulic control valve is in reverse conduction and is opened, the hydraulic oil at the forward oil outlet is decompressed to the oil tank loop through the hydraulic control valve reverse conduction control oil circuit, so that the impact when the hydraulic control valve is opened is avoided. When the hydraulic control valve is switched from reverse conduction to cut-off, hydraulic oil of the forward oil outlet releases pressure to the forward oil inlet through the differential pressure control oil path, and impact of the hydraulic control valve from reverse conduction to cut-off is avoided. Thereby making the whole hydraulic system operate smoothly.
Claims (8)
1. A balance valve is characterized by comprising a forward oil inlet, a forward oil outlet and an oil return port, and a hydraulic control valve, wherein a differential pressure control oil path connected with the hydraulic control valve in parallel is arranged between the forward oil inlet and the forward oil outlet, and a hydraulic control valve reverse conduction control oil path is arranged between the forward oil inlet and the oil return port;
the hydraulic control valve is connected between the forward oil inlet and the forward oil outlet, the hydraulic control valve is conducted in the forward direction when the forward oil inlet is filled with oil, the forward oil outlet is filled with oil in the reverse direction, and the acting force of the hydraulic oil in an oil cavity where the hydraulic control valve is connected with the forward oil outlet, which acts on the valve core of the hydraulic control valve, is greater than the acting force of the spring at the hydraulic control end of the hydraulic control valve and the acting force of the hydraulic oil on the valve core, and the hydraulic control valve is conducted in;
the pressure difference control oil way comprises a first electromagnetic switch valve and a first throttle valve (66) which are sequentially connected in series from a forward oil outlet to a forward oil inlet;
the hydraulic control valve reverse conduction control oil path comprises an oil inlet end and a second throttle valve (67) connected with the self-forward oil outlet, and a second electromagnetic switch valve (63) and a differential pressure control switch valve which are connected in series are arranged on the oil path between the oil outlet end of the second throttle valve and the oil return port;
the hydraulic control end of the hydraulic control valve is connected with the oil outlet end of the second throttling valve, and the hydraulic control ends at the two ends of the differential pressure control switch valve are respectively connected with the oil inlet end and the oil outlet end of the first throttling valve (66);
the first electromagnetic switch valve and the second electromagnetic switch valve are in a cut-off state normally; the normal state of the differential pressure control switch valve is a conduction state, and the differential pressure control switch valve is in a cut-off state when the acting force of the differential pressure at the two ends of the first throttle valve at the two ends of the valve core of the differential pressure control switch valve is greater than the spring force acting on the valve core of the differential pressure control switch valve.
2. The balance valve according to claim 1, wherein the differential pressure control oil passage further comprises a third throttle valve (65) provided between the forward oil outlet and the first throttle valve (66) and connected in series with the first electromagnetic opening-closing valve (62).
3. The balancing valve according to claim 1, characterized in that a fourth throttle (68) is further provided in series between the second throttle (67) and the return port (T) on the pilot-operated valve reverse conduction control oil path.
4. The balance valve according to any one of claims 1 to 3, wherein a two-way cut-off valve is provided between an oil inlet end and an oil outlet end of the first electromagnetic opening/closing valve in the cut-off state.
5. The balance valve according to any one of claims 1 to 3, wherein a check valve is provided between an oil inlet end and an oil outlet end of the second electromagnetic opening/closing valve in the off state.
6. A lifting hydraulic system comprises a lifting oil cylinder, a lifting oil cylinder control valve, a lifting control device for controlling the lifting oil cylinder control valve, a lifting operation detection device for detecting the lifting operation of the lifting control device, and a controller, a lifting operation detection device connected with the controller and used for detecting the lifting operation of the lifting control device, and a balance valve according to any one of claims 1 to 5, wherein a forward oil inlet and a forward oil outlet of the balance valve are connected in series with an oil circuit between the lifting oil cylinder control valve and a lifting cavity of the lifting oil cylinder, an oil return port of the balance valve is connected with an oil tank loop, electromagnetic ends of a first electromagnetic switch valve and a second electromagnetic switch valve of the balance valve are connected with the controller, and when the lifting operation detection device detects the falling operation of the lifting control device, the controller outputs a controller signal to enable the second electromagnetic switch valve to be in a conducting state firstly and then enable the first electromagnetic switch to be in a conducting state And (4) an on state.
7. A working machine characterized by having a balancing valve as claimed in any one of claims 1 to 5 or by having a lifting hydraulic system as claimed in claim 6.
8. The working equipment according to claim 7, characterized in that the working equipment is a mining dump truck, and the lifting hydraulic system is a bucket lifting hydraulic system; or the working equipment is a loader, and the lifting hydraulic system is a movable arm lifting hydraulic system; or the working equipment is an excavator, and the lifting hydraulic system is a movable arm lifting hydraulic system; or the operation equipment is a forklift, and the lifting hydraulic system is a fork lifting hydraulic system; or the operation equipment is a crane, and the lifting hydraulic system is a suspension arm lifting hydraulic system; or the operation equipment is a front crane, and the lifting hydraulic system is a suspension arm lifting hydraulic system.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810705466.XA CN108561362B (en) | 2018-07-02 | 2018-07-02 | Balance valve, hydraulic lifting system and operation machine |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810705466.XA CN108561362B (en) | 2018-07-02 | 2018-07-02 | Balance valve, hydraulic lifting system and operation machine |
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| CN108561362A CN108561362A (en) | 2018-09-21 |
| CN108561362B true CN108561362B (en) | 2019-12-20 |
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| CN201810705466.XA Active CN108561362B (en) | 2018-07-02 | 2018-07-02 | Balance valve, hydraulic lifting system and operation machine |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111152838B (en) * | 2018-11-08 | 2023-08-15 | 潍柴(扬州)特种车有限公司 | Hydraulic integrated control device for mine car steering system and box lifting system |
| CN109336006B (en) * | 2018-12-10 | 2020-04-24 | 宁波华液机器制造有限公司 | Electric fork-lift valve body assembly |
| CN112065802B (en) * | 2020-09-29 | 2024-06-25 | 浙江海宏液压科技股份有限公司 | Hydraulic lifting system |
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| JP2004036750A (en) * | 2002-07-03 | 2004-02-05 | Aichi Corp | Cylinder operation control device |
| CN203835843U (en) * | 2014-05-09 | 2014-09-17 | 长沙中联消防机械有限公司 | Balance valve group, hydraulic control loop and engineering machinery |
| CN105035979A (en) * | 2015-08-05 | 2015-11-11 | 常德中联重科液压有限公司 | Balance valve group and hydraulic system |
| CN106185633A (en) * | 2016-08-24 | 2016-12-07 | 三汽车起重机械有限公司 | Balancing valve apparatus, crane and elevating mechanism |
| CN206955583U (en) * | 2017-07-26 | 2018-02-02 | 河南垣发专用车辆集团有限公司 | A kind of vibration reduction and cushioning control system for being applied to fork installation load walking |
-
2018
- 2018-07-02 CN CN201810705466.XA patent/CN108561362B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004036750A (en) * | 2002-07-03 | 2004-02-05 | Aichi Corp | Cylinder operation control device |
| CN203835843U (en) * | 2014-05-09 | 2014-09-17 | 长沙中联消防机械有限公司 | Balance valve group, hydraulic control loop and engineering machinery |
| CN105035979A (en) * | 2015-08-05 | 2015-11-11 | 常德中联重科液压有限公司 | Balance valve group and hydraulic system |
| CN106185633A (en) * | 2016-08-24 | 2016-12-07 | 三汽车起重机械有限公司 | Balancing valve apparatus, crane and elevating mechanism |
| CN206955583U (en) * | 2017-07-26 | 2018-02-02 | 河南垣发专用车辆集团有限公司 | A kind of vibration reduction and cushioning control system for being applied to fork installation load walking |
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| Publication number | Publication date |
|---|---|
| CN108561362A (en) | 2018-09-21 |
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