CN114060345A - Pilot control valve, engineering machinery hydraulic control system and engineering machinery - Google Patents
Pilot control valve, engineering machinery hydraulic control system and engineering machinery Download PDFInfo
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- CN114060345A CN114060345A CN202111392475.6A CN202111392475A CN114060345A CN 114060345 A CN114060345 A CN 114060345A CN 202111392475 A CN202111392475 A CN 202111392475A CN 114060345 A CN114060345 A CN 114060345A
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- valve
- spring seat
- piston unit
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- 239000003921 oil Substances 0.000 claims description 96
- 230000000670 limiting effect Effects 0.000 claims description 31
- 230000000712 assembly Effects 0.000 claims description 19
- 238000000429 assembly Methods 0.000 claims description 19
- 239000010720 hydraulic oil Substances 0.000 claims description 8
- 230000002093 peripheral effect Effects 0.000 claims description 3
- 230000008859 change Effects 0.000 abstract description 13
- 238000010276 construction Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 230000002441 reversible effect Effects 0.000 description 4
- 210000004907 gland Anatomy 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000006837 decompression Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
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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
- 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
- F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
- F15B13/0401—Valve members; Fluid interconnections therefor
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F3/00—Dredgers; Soil-shifting machines
- E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2264—Arrangements or adaptations of elements for hydraulic drives
- E02F9/2267—Valves or distributors
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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
- F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
- F15B1/02—Installations or systems with accumulators
- F15B1/024—Installations or systems with accumulators used as a supplementary power source, e.g. to store energy in idle periods to balance pump load
-
- 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
- F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
-
- 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
- F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
- F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
- F15B13/0422—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with manually-operated pilot valves, e.g. joysticks
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
- F15B21/04—Special measures taken in connection with the properties of the fluid
- F15B21/041—Removal or measurement of solid or liquid contamination, e.g. filtering
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
- F15B21/08—Servomotor systems incorporating electrically operated control means
- F15B21/087—Control strategy, e.g. with block diagram
Abstract
The invention relates to the technical field of hydraulic control, and discloses a pilot control valve, an engineering machinery hydraulic control system and engineering machinery. According to the pilot control valve provided by the invention, the piston unit is connected with the first stroke adjusting piece, and the first stroke adjusting unit is used for adjusting the maximum stroke of the piston unit moving from the limit position when the piston unit moves upwards to the limit position when the piston unit moves downwards. The rotation range of the handle assembly is determined, the maximum stroke of the piston unit moving from one extreme position to the other extreme position is changed through the first stroke adjusting piece, the stroke of the piston unit is different when the handle assembly rotates by the same angle, the change of the fine adjustment characteristic of the hydraulic system is realized when the handle assembly is applied to the hydraulic system of the engineering machinery, and the fine adjustment characteristic of the hydraulic system can be adjusted according to the requirements of different users on the operation speed and comfort, so that the requirements of the users can be met.
Description
Technical Field
The invention relates to the technical field of hydraulic control, in particular to a pilot control valve, an engineering machinery hydraulic control system and engineering machinery.
Background
The pilot control valve adopts the working principle of a direct-acting pressure reducing valve and is suitable for pilot control of hydraulic reversing valves of engineering machinery such as excavators, loaders, cranes, concrete pump trucks and the like. In the case of a crawler-type hydraulic excavator, a pilot hydraulic system of the crawler-type hydraulic excavator is an important part of a hydraulic system of the whole excavator, and affects operability, comfort, construction accuracy and the like of the excavator.
Taking a crawler-type hydraulic excavator as an example, the crawler-type hydraulic excavator outputs a secondary pressure to a pilot end of a main control valve through a pilot hydraulic system to drive a main valve core of the main control valve to move so as to control the stroke amount and the moving direction of the main valve core, and the stroke amount of a control valve in the pilot hydraulic system determines the operating angle of an operating handle, so that the opening sensitivity of the main valve core is influenced to a certain extent, and the response speed of the working devices of the crawler-type hydraulic excavator, such as a swing mechanism, an arm, a bucket, a boom and the like, is influenced.
Because different working devices have different flow requirements in the operation process of the crawler-type hydraulic excavator, the pilot secondary pressures for controlling the movable arm valve core, the bucket rod valve core, the bucket valve core and the rotary valve core in each main control valve are different, namely the angle of the control handle corresponds to the output secondary pressure curve. The pilot control valve in the existing pilot hydraulic system is mostly of an integrated design, namely, a plurality of valve holes are formed in one valve body, a set of valve core assembly is installed in each valve hole, and an operating handle selectively controls the action of the valve core of any one valve core assembly through a universal joint.
The existing pilot control valves have the following disadvantages: the rotation angle of the pilot handle on the engineering machinery corresponds to the flow of the main control valve one by one, and the flow of the main control valve changes along with the change of the rotation angle of the pilot handle, which is the so-called speed regulation characteristic of a hydraulic system. The rotation angle of the pilot handle can directly reflect the valve core stroke of the pilot control valve, when the valve core stroke is maximum, the flow of the main control valve reaches the maximum, and the speed regulation characteristic range of the hydraulic system is related to the valve core stroke of the pilot control valve.
The degree of change in the flow rate of the main control valve with the spool stroke of the pilot control valve in the speed regulation range is referred to as the trim characteristic of the hydraulic system. Obviously, when the angle change of the pilot handle is large and the flow change of the main control valve is smaller, the fine adjustment performance of the system is good, an operator can control the system more easily, and the fine adjustment performance is poor. The requirements of users on the speed regulation characteristic are different for different models, even for different countries and regions with the same model. For example, for a machine type requiring a high operation speed, the fine adjustment performance is not good; for the machine type which requires high operation speed and certain comfort, the good balance between operation speed and fine adjustment characteristic is required, and particularly, a plurality of users require the excavator to have the micro-motion characteristic and the land leveling function, so that the excavator is easy to operate on the flat land by taking measures generally; for the working condition mode of hoisting, fine adjustment and even precise adjustment are very important.
Therefore, the operation speed and the comfort are contradictory, and the flow characteristics of the pilot control valve and the main control valve in the prior art are fixed, which is difficult to satisfy the user requirements. Although the requirements of users on operation speed and comfort can be met by replacing different parts, the replacement is complicated, and the cost is increased by arranging different parts as standby.
Disclosure of Invention
The invention aims to provide a pilot control valve, an engineering machinery hydraulic control system and engineering machinery, which can meet the requirements of different users on operation speed and comfort.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a pilot control valve, which comprises a valve body and at least two valve core assemblies, wherein the valve body is provided with an oil inlet, pressure chambers corresponding to the valve core assemblies one by one and oil outlet corresponding to the pressure chambers one by one, and the valve core assemblies are used for controlling the oil inlet to be selectively communicated or disconnected with the corresponding oil outlet through the pressure chambers;
the spool assembly includes:
the piston unit is arranged in the pressure cavity in a sliding manner;
a return spring configured to cause the piston unit to have a tendency to move upward;
a universal assembly and a handle assembly, the handle assembly being rotatable relative to the piston unit via the universal assembly to drive the piston unit down;
the valve body is provided with an upper limiting piece for limiting the limit position when the piston unit moves upwards and a lower limiting piece for limiting the limit position when the spring seat moves downwards;
the piston unit is connected with a first stroke adjusting piece and used for adjusting the maximum stroke of the piston unit from the limit position when the piston unit moves upwards to the limit position when the piston unit moves downwards.
According to the pilot control valve provided by the invention, the piston unit is connected with the first stroke adjusting piece, and the first stroke adjusting unit is used for adjusting the maximum stroke of the piston unit moving from the limit position when the piston unit moves upwards to the limit position when the piston unit moves downwards. The rotation range of the handle assembly is determined, the maximum stroke of the piston unit moving from one extreme position to the other extreme position is changed through the first stroke adjusting piece, the stroke of the piston unit is different when the handle assembly rotates by the same angle, the change of the fine adjustment characteristic of the hydraulic system is realized when the handle assembly is applied to the hydraulic system of the engineering machinery, and the fine adjustment characteristic of the hydraulic system can be adjusted according to the requirements of different users on the operation speed and comfort, so that the requirements of the users can be met.
As an optimal technical scheme of the above pilot control valve, the valve body inner wall is provided with a reset limiting surface located below the spring seat, and the piston unit includes:
the ejector rod is arranged in the pressure cavity in a sliding manner;
the first stroke adjusting piece is connected to the spring seat, and the reset spring is clamped between the spring seat and the reset limiting surface;
the valve core penetrates through the spring seat, and the ejector rod can slide or be fixed relative to the valve core along the vertical direction;
the periphery wall of case is equipped with and is located the spacing face of spring holder below, the spring holder with press from both sides between the spacing face of spring and be equipped with relief spring.
As a preferable technical solution of the pilot control valve, the first stroke adjusting member is a boss provided on both upper and lower sides of the spring seat, and the bosses located on both upper and lower sides of the spring seat have different lengths in a vertical direction;
the bosses located on any side of the spring seat can be abutted to the lower limiting part.
The first stroke adjusting piece is simple in structure, the first stroke adjusting piece is turned over by 180 degrees up and down and then is placed into the pressure cavity, the change of the fine adjustment characteristic of the hydraulic system can be achieved, and the fine adjustment characteristic of the hydraulic system can be adjusted according to the requirements of different users on operation speed and comfort, so that the requirements of the users are met.
As a preferable technical solution of the above pilot control valve, an avoidance space is provided on the valve body for accommodating the boss located above the spring seat.
Through setting up and dodging the space, can avoid the spring holder positive and negative dress to influence reset spring's initial pressure, when making the extreme position when piston unit is located the shifting up, spacing cooperation portion and the upper portion locating part butt of ejector pin lower extreme.
As a preferable technical solution of the above pilot control valve, the pilot control valve further includes a second stroke adjusting member, and a thickness of the second stroke adjusting member in the vertical direction is adjustable;
the second stroke adjusting piece is connected to one of the lower end of the ejector rod and the upper end of the valve core, and the second stroke adjusting piece is selectively abutted against the other one in the vertical direction or separated from the other one, so that the ejector rod can move downwards relative to the valve core when the piston unit is at the limit position when moving upwards.
The maximum stroke of the spring seat when the spring seat moves from the limit position when the spring seat moves upwards to the position where the second stroke adjusting piece is clamped between the ejector rod and the valve core along the vertical direction is changed by changing the thickness of the second stroke adjusting piece in the vertical direction.
As a preferable technical solution of the above pilot control valve, the lower end of the ejector rod is provided with a sliding groove with a downward opening, and the upper end of the valve core is convexly provided with a sliding convex part which is in sliding fit with the sliding groove along the vertical direction;
the second stroke adjusting piece is connected to the sliding convex part and is arranged between the inner bottom wall of the sliding groove and the upper end face of the sliding convex part.
As a preferable technical solution of the above pilot control valve, a limit fitting portion located below the upper limiting member is provided at the lower end of the ejector rod, and the limit fitting portion can abut against the upper limiting member.
The limit matching part is abutted with the upper limit part, so that the effect of limiting the ejector rod is achieved when the ejector rod moves upwards.
In a second aspect, the invention also provides an engineering machinery hydraulic control system, which comprises the pilot control valve, an
An oil supply unit and a working oil cylinder;
the oil supply unit can control the piston rod of the working oil cylinder to stretch through the main control valve which is a hydraulic control valve;
the oil inlet hole of the pilot control valve can be selectively communicated with the oil outlet of the oil supply unit or the hydraulic oil tank through the unlocking electromagnetic valve, and the oil outlet hole of the pilot control valve is communicated with the hydraulic control end of the main control valve.
When the unlocking electromagnetic valve enables the oil inlet hole of the pilot control valve to be communicated with the outlet of the oil supply unit, the oil supply unit sends working oil to the oil inlet hole of the pilot control valve through the unlocking electromagnetic valve, when the pilot control valve enables the oil inlet hole and the oil outlet hole to be communicated, the working oil of the oil inlet can flow to the hydraulic control end of the main control valve through the pilot control valve, the oil pressure of the hydraulic control end of the main control valve is increased, and therefore the working state of the main control valve is adjusted. When the unlocking electromagnetic valve enables the oil inlet hole of the pilot control valve to be communicated with the hydraulic oil tank, working oil at the hydraulic control end of the main control valve flows back to the hydraulic oil tank through the pilot control valve and the unlocking electromagnetic valve, pressure relief of the hydraulic control end of the main control valve is achieved, and the main control valve is reset.
As a preferred technical scheme of the hydraulic control system for the engineering machinery, an outlet of the oil supply unit is connected with an inlet of the unlocking electromagnetic valve through a control oil path, and the control oil path is provided with a one-way valve and an energy accumulator which are sequentially arranged along the flowing direction of oil therein.
Working oil in the control oil way is prevented from flowing backwards through the one-way valve, after the engineering machinery is shut down, the whole machine is powered on when the engine is not started, the unlocking electromagnetic valve is powered on for reversing, the working oil in the energy accumulator enters the oil inlet hole of the pilot control valve through the unlocking electromagnetic valve, and when the pilot control valve enables the oil inlet hole and the oil outlet hole to be communicated, pressure oil flows to the hydraulic control end of the main control valve through the pilot control valve to adjust the state of the main control valve.
In a third aspect, the invention provides an engineering machine, which comprises the hydraulic control system of the engineering machine, and can meet the requirements of different users on operation speed and comfort.
The invention has the beneficial effects that: according to the pilot control valve provided by the invention, the piston unit is connected with the first stroke adjusting piece, and the first stroke adjusting unit is used for adjusting the maximum stroke of the piston unit moving from the limit position when the piston unit moves upwards to the limit position when the piston unit moves downwards. The rotation range of the handle assembly is determined, the maximum stroke of the piston unit moving from one extreme position to the other extreme position is changed through the first stroke adjusting piece, the stroke of the piston unit is different when the handle assembly rotates by the same angle, the change of the fine adjustment characteristic of the hydraulic system is realized when the handle assembly is applied to the hydraulic system of the engineering machinery, and the fine adjustment characteristic of the hydraulic system can be adjusted according to the requirements of different users on the operation speed and comfort, so that the requirements of the users can be met.
The engineering machinery hydraulic control system and the engineering machinery provided by the invention can meet the requirements of different users on operation speed and comfort by adopting the pilot control valve.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.
FIG. 1 is a hydraulic schematic diagram of a hydraulic control system of a construction machine according to an embodiment of the invention;
FIG. 2 is a cross-sectional view of a pilot control valve provided in accordance with an embodiment of the present invention;
FIG. 3 is an enlarged partial schematic view at I of FIG. 2;
FIG. 4 is a graphical illustration of the relationship between spool travel and secondary pressure for two adjacent spool assemblies of a pilot control valve provided by an embodiment of the present invention;
fig. 5 is a graph of the relationship between the spool stroke and the secondary pressure of adjacent spool assemblies of the pilot control valve when the second stroke adjuster has different thicknesses in the vertical direction.
In the figure:
11. a valve body; 12. a jack rod seat;
2. a gimbal assembly;
31. a top rod; 311. a sliding groove; 312. a limit matching part; 313. an upper limit piece; 314. avoiding a space; 32. a spring seat; 321. a boss; 33. a valve core; 331. a sliding projection; 34. a return spring; 35. a relief spring; 36. a second stroke adjustment member;
100. a variable main pump; 200. a pilot constant delivery pump; 300. unlocking the electromagnetic valve; 400. a pilot control valve; 500. a main control valve; 600. a working oil cylinder; 700. a hydraulic oil tank; 800. an accumulator; 900. a one-way valve.
Detailed Description
In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.
As shown in fig. 1 to 3, the present embodiment provides a hydraulic control system for a construction machine, which may be an excavator, a bulldozer, a loader, a crane, or the like. The engineering machinery hydraulic control system comprises an oil supply unit, a main control valve 500, a working oil cylinder 600, a pilot control valve 400 and an unlocking electromagnetic valve 300, wherein the oil supply unit comprises a variable main pump 100 and a pilot constant delivery pump 200 which are driven by the same driving unit such as a motor, and the variable main pump 100 can control the extension and contraction of a piston rod of the working oil cylinder 600 through the main control valve 500. For different engineering machines, the adopted main control valves 500 may be different, the same engineering machine may also adopt a plurality of main control valves 500, and the structures of the main control valves 500 adopted by different engineering machines to control the corresponding working cylinders 600 to extend and retract through the main control valves 500 are all the prior art, and the main control valves 500 are not described in detail herein.
The main control valve 500 is a pilot operated valve, an oil inlet of the pilot operated valve 400 is communicated with an outlet of the pilot constant delivery pump 200 or the hydraulic oil tank 700 through the unlocking solenoid valve 300, an oil outlet of the pilot operated valve 400 is communicated with a pilot operated end of the main control valve 500, and the pilot operated valve 400 enables the oil inlet to be selectively communicated with or disconnected from the oil outlet. When the unlocking solenoid valve 300 communicates the oil inlet of the pilot control valve 400 with the outlet of the pilot constant delivery pump 200, the pilot constant delivery pump 200 delivers the working oil to the oil inlet of the pilot control valve 400 through the unlocking solenoid valve 300, and when the pilot control valve 400 communicates the oil inlet with the oil outlet, the working oil of the oil inlet flows to the pilot control end of the main control valve 500 through the pilot control valve 400, increasing the oil pressure of the pilot control end of the main control valve 500, thereby adjusting the operating state of the main control valve 500. When the unlocking solenoid valve 300 communicates the oil inlet of the pilot control valve 400 with the hydraulic oil tank 700, the working oil at the hydraulic control end of the main control valve 500 flows back to the hydraulic oil tank 700 through the pilot control valve 400 and the unlocking solenoid valve 300, so as to realize the pressure relief of the hydraulic control end of the main control valve 500 and reset the main control valve 500. Illustratively, the unlock solenoid valve 300 is a two-position, three-way solenoid valve.
Further, an outlet of the pilot constant delivery pump 200 is connected to an inlet of the unlocking solenoid valve 300 through a control oil path, the control oil path is provided with a check valve 900 and an energy accumulator 800 which are sequentially arranged along a flow direction of oil therein, after the engineering machine is stopped, the whole machine is powered on when the engine is not started, so that the power on of the unlocking solenoid valve 300 is reversed, working oil in the energy accumulator 800 enters an oil inlet of the pilot control valve 400 through the unlocking solenoid valve 300, when the pilot control valve 400 communicates the oil inlet with the oil outlet, pressure oil flows to a hydraulic control end of the main control valve 500 through the pilot control valve 400, and the state of the main control valve 500 is adjusted.
The control oil way is provided with a first filter positioned at the upstream of the one-way valve 900, the control oil way is connected with a pressure relief oil way, the connecting position of the pressure relief oil way and the control oil way is positioned at the upstream of the first filter, and the pressure relief oil way is provided with a second filter and an overflow valve. The first filter and the second filter mainly function to filter the working oil, and the relief valve serves as a safety valve to protect the pilot constant delivery pump 200 from high pressure. In other embodiments, the connection position between the pressure relief oil path and the control oil path may be set between the first filter and the check valve 900, and at this time, only one overflow valve needs to be set on the pressure relief oil path, and a second filter does not need to be set.
Further, the pilot control valve 400 provided by this embodiment includes a valve body and at least two valve core assemblies, the valve body is provided with an oil inlet, a pressure chamber corresponding to the valve core assemblies one by one, and an oil outlet corresponding to the pressure chamber one by one, and the valve core assemblies are used to control the oil inlet to selectively communicate or disconnect with the corresponding oil outlet through the pressure chamber. Illustratively, the valve core assemblies are four, and four valve core assemblies are distributed circumferentially. In other embodiments, the spool assembly may be two, three, five, or more.
The valve core assembly comprises a piston unit and a return spring 34, wherein the piston unit is arranged in the pressure cavity in a sliding mode, and the return spring 34 is configured to enable the piston unit to have a tendency to move upwards; the valve body is provided with an upper limit member 313 that defines the limit position when the piston unit moves upward, and a lower limit member that defines the limit position when the piston unit moves downward.
The above-mentioned reset spring 34 is a compression spring, and the valve body includes a valve body 11 and a push rod base 12, wherein, the pressure chamber is arranged on the valve body 11, the push rod base 12 is fixedly arranged in the pressure chamber and is slidably sleeved outside the push rod 31, the above-mentioned upper limit piece 313 is the lower end surface of the push rod base 12, and the lower limit piece is the step surface arranged in the pressure chamber on the valve body 11.
The inner wall of the valve body 11 is provided with a reset limiting surface located below the spring seat 32, the piston unit comprises a push rod 31, a spring seat 32 and a valve core 33, the push rod 31 and the spring seat 32 are arranged in the pressure cavity in a sliding mode, the spring seat 32 is located below the push rod 31 and is abutted to the push rod 31 in the vertical direction, the first stroke adjusting piece is connected to the spring seat 32, and the reset spring 34 is clamped between the spring seat 32 and the reset limiting surface. The valve core 33 penetrates through the spring seat 32, and the valve core 33 can slide or be fixed relative to the ejector rod 31 in the vertical direction; the outer peripheral wall of the valve element 33 is provided with a spring stopper surface located below the spring seat 32, a pressure reducing spring 35 is interposed between the spring seat 32 and the spring stopper surface, and the pressure reducing spring 35 is a compression spring.
In order to facilitate installation of the return spring 34 and the pressure reducing spring 35, a through hole is formed in the spring seat 32, the through hole is a stepped hole, a first stepped surface and a second stepped surface located below the first stepped surface are formed at the lower end of the through hole, the return spring 34 is clamped between the second stepped surface and the lower limiting part, and the pressure reducing spring 35 is clamped between the spring limiting surface and the first stepped surface.
The lower end of the top rod 31 is provided with a limit engagement portion 312 located below the upper limit piece 313, and the limit engagement portion 312 can abut against the upper limit piece 313. Illustratively, the limiting fitting part 312 is an annular boss protruding from the outer peripheral wall of the lower end of the top rod 31, the upper end surface of the annular boss can abut against the upper limiting part 313 to limit the position of the piston unit, and the lower end surface of the annular boss abuts against the spring seat 32 in the vertical direction, so that the top rod 31 can push the spring seat 32 to move downward.
The pilot control valve 400 has a neutral position and an operating position, and when the pilot control valve 400 is in the neutral position, the pressure reducing spring 35 is in a natural state, the return spring 34 is in a compressed state, and the spring seat 32 abuts against the upper limit stopper 313 under the action of the return spring 34, so that the oil inlet hole is disconnected from the corresponding pressure chamber, and the jack 31 can move downward relative to the spool 33. When the ejector rod 31 moves downwards, the ejector rod 31 pushes the spring seat 32 to move downwards, the return spring 34 and the decompression spring 35 are both compressed, and the ejector rod 31 moves downwards relative to the valve core 33; when the return spring 34 and the pressure-reducing spring 35 are compressed to a certain extent, the spool 33 starts moving down; as the valve core 33 moves downwards gradually, the oil inlet hole is communicated with the corresponding pressure cavity, and the communication opening degree between the oil inlet hole and the corresponding pressure cavity is gradually increased; when the push rod 31 is abutted against the valve core 33 in the vertical direction, the push rod 31 and the valve core 33 are relatively fixed, the push rod 31 pushes the valve core 33 and the spring seat 32 to synchronously move downwards until the spring seat 32 is abutted against the lower limiting part, and the spring seat 32 reaches a limit position when moving downwards, so that the communication opening degree between the oil inlet hole and the corresponding pressure cavity is maximized.
Further, the upper end face of the ejector rod 31 is an arc face, the universal assembly 2 is arranged above the ejector rod 31, the universal assembly 2 comprises an adjusting gland, the lower end face of the adjusting gland is a curved face, the upper end face of the ejector rod 31 of any valve core assembly can be abutted to the curved face, and the universal assembly 2 is connected with a handle assembly which is rotatably connected with the handle assembly. When a driver operates the handle assembly, according to the rotation direction of the handle assembly, the universal assembly 2 applies an external force to the arc surface at the upper end of the ejector rod 31 by adjusting the curved surface on the lower end surface of the gland, pushes the ejector rod 31 to move downwards and pushes the spring seat 32 to move downwards, compresses the return spring 34, and then pushes the valve core 33 to move downwards through the return spring 34. The construction of the gimbal assembly 2 and the handle assembly are prior art and will not be described in detail herein.
Further, a first stroke adjusting piece is connected with the piston unit and used for adjusting the maximum stroke of the piston unit from the limit position when the piston unit moves upwards to the limit position when the piston unit moves downwards. Because the rotation range of the handle assembly is determined, the maximum stroke of the spring seat 32 moving from one extreme position to the other extreme position is changed through the first stroke adjusting piece, so that when the handle assembly rotates by the same angle, the strokes of the valve core 33 are different, when the handle assembly is applied to a hydraulic system of engineering machinery, the change of the fine adjustment characteristic of the hydraulic system is realized, and the fine adjustment characteristic of the hydraulic system can be adjusted according to the requirements of different users on the operation speed and comfort, so as to meet the requirements of the users.
Specifically, the first stroke adjusting member is bosses 321 arranged on the upper side and the lower side of the spring seat 32, and the bosses 321 on the upper side and the lower side of the spring seat 32 have different lengths in the vertical direction; the bosses 321 on either side of the spring seat 32 can abut against the lower stopper.
In this embodiment, the shorter boss 321 is located above the spring seat 32 and is marked as forward mounting of the spring seat 32, the shorter boss 321 is located below the spring seat 32 and is marked as reverse mounting of the spring seat 32, and the spring seat 32 can be mounted in a forward mounting or reverse mounting manner according to actual requirements so as to adjust the distance between the boss 321 located below the spring seat 32 and the lower limiting member when the spring seat 32 is located at the limit position when moving upward. In this embodiment, the mounting directions of the spring seats 32 of two adjacent valve core assemblies are opposite, that is, one is normally installed and the other is reversely installed, the maximum stroke of the normally installed spring seat 32 is C, and the maximum stroke of the reversely installed spring seat 32 is B.
In order to facilitate the spring seat 32 to be turned 180 degrees up and down, the spring seat 32 can still limit the return spring 34 and the relief spring 35, and a first step surface and a second step surface are formed at both axial ends of the through hole.
In order to avoid the influence of the normal and reverse installation of the spring seat 32 on the initial pressure of the return spring 34, an escape space 314 is provided in the valve body for accommodating the boss 321 located above the spring seat 32, so that when the piston unit is located at the limit position at the time of upward movement, the limit engagement portion 312 at the lower end of the jack 31 abuts against the upper limit stopper 313. Illustratively, the bosses 321 on the upper and lower sides of the spring seat 32 are annular structures, and the avoiding space 314 is an annular groove formed in the lower end surface of the ejector rod seat 12, so that when the spring seat 32 is located at the limit position when moving upward regardless of whether the spring seat 32 is installed in the forward or reverse direction, the upper side surface of the limit engaging portion 312 abuts against the upper limit stopper 313, and the lower end surface of the limit engaging portion 312 abuts against the spring seat 32 in the vertical direction, so that the initial pressures of the return springs 34 are the same. The outer diameter of the spring seat 32 is equal in diameter and equal to the outer diameter of the bosses 321 located on the upper and lower sides of the spring seat 32, so that the spring seat 32 can be turned over by 180 degrees up and down and then can be slidably fitted into the pressure chamber, the boss 321 on one side of the spring seat 32 can be inserted into the avoiding space 314, and the boss 321 on the other side can abut against the lower limiting member.
In other embodiments, the first stroke adjusting element may be a telescopic rod capable of extending and retracting in a vertical direction relative to the spring seat 32, for example, the telescopic rod is in threaded connection with the spring seat 32, the telescopic rod is screwed to adjust the length of the telescopic rod extending downward out of the spring seat 32, and when the spring seat 32 is located at the extreme position when moving upward, the distance between the boss 321 located below the spring seat 32 and the lower limiting element is adjusted. In order to guarantee that spring holder 32 atress is balanced, the telescopic link is equipped with a plurality ofly, and a plurality of telescopic links are along the equal interval distribution of circumference of spring holder 32, and the length that every telescopic link stretches out spring holder 32 downwards equals. Optionally, scale marks are arranged on the telescopic rod, so that a user can quickly know the distance of the telescopic rod extending out of the spring seat 32 downwards.
Further, the pilot control valve 400 further includes a second stroke adjustment member 36, and the thickness of the second stroke adjustment member 36 in the vertical direction is adjustable; the second stroke adjusting member 36 is attached to one of the plunger 31 and the spool 33, and the second stroke adjusting member 36 selectively abuts the other in the vertical direction or is separated so that the plunger 31 can move down relative to the spool 33 when the piston unit is at the extreme position at the time of moving up. By changing the thickness of the second stroke adjustment member 36 in the vertical direction, the maximum stroke of the spring seat 32 when the spring seat 32 moves from the limit position at the time of upward movement to a position where the second stroke adjustment member 36 is interposed between the jack 31 and the spool 33 in the vertical direction is changed.
Specifically, the lower end surface of the top rod 31 is provided with a sliding groove 311 with a downward opening, the upper end of the valve core 33 is convexly provided with a sliding convex part 331 which is in sliding fit with the sliding groove 311 along the vertical direction, and the second stroke adjusting piece 36 is connected to the sliding convex part 331 and is arranged between the inner bottom wall of the sliding groove 311 and the upper end surface of the sliding convex part 331. In another embodiment, a sliding protrusion may be provided on the lower end surface of the plunger 31, and a sliding groove with an upward opening may be provided on the upper end surface of the valve body 33.
The second stroke adjusting member 36 is a gasket, and the thickness of the second stroke adjusting member 36 in the vertical direction can be adjusted by replacing gaskets with different thicknesses or different numbers of gaskets. The present embodiment adjusts the thickness of the second stroke adjustment member 36 in the vertical direction using a different number of shims of the same thickness. The length of the second stroke adjustment member 36 in the vertical direction is kA, a is the thickness of a single shim, and k is the number of shims. When the piston unit is at the extreme position at the time of upward movement, the distance between the upper end surface of the second stroke adjuster 36 and the inner bottom wall of the slide groove 311 is D. In this embodiment, the second stroke adjusting part 36 corresponding to the valve core assembly where the normally installed spring seat 32 is located adopts two gaskets with the same thickness, and the thickness of the second stroke adjusting part 36 corresponding to the valve core assembly where the reversely installed spring seat 32 is located is zero. To facilitate the installation of the second stroke adjusting member 36, a screw passes through the second stroke adjusting member 36 and is screwed to the sliding protrusion 331. In other embodiments, the second stroke adjustment member 36 may be mounted on the inner bottom wall of the sliding groove 311.
Further, the outer diameter of the sliding protrusion 331 is larger than the outer diameter of the valve body 33 contacting therewith, and the inner diameter of the through hole is smaller than the outer diameter of the sliding protrusion 331 and larger than the outer diameter of the valve body 33 contacting with the sliding protrusion 331, thereby limiting the push rod 31 to be able to press-contact with the second stroke adjuster 36.
Further, in the prior art, the similarity of the parts of the two types of valve core assemblies forming the four sets of valve core assemblies is very high, for example, the ejector rods and the spring seats of the two types of valve core assemblies are two different parts, which are easily confused and mistakenly assembled during production, assembly, and maintenance, and need to be strictly controlled on the production process, the assembly process, and the maintenance process, and have the defect of high cost of part assembly and production and manufacturing. In addition, in the assembling and maintaining processes, the parts of one type of valve core assembly are mistakenly installed in the adjacent valve holes, so that the stroke change of the valve core can be caused, the pressure performance of a working oil port corresponding to the type of valve core assembly can be seriously influenced, and even the performance of the main control valve can be seriously influenced, so that the operation of an actuating mechanism of the excavator is influenced, the excavator can not meet the working requirements of users, and the product rejection rate is higher. Therefore, the spring seat 32 with the same structure is adopted in the embodiment, only the spring seat 32 needs to be turned over up and down, and the length of the second stroke adjusting part 36 in the vertical direction is set according to the requirement, so that the structure of the pilot control valve 400 is greatly simplified, the probability of misassembly is reduced, and the yield of the pilot control valve 400 is improved.
Referring to fig. 2 and 3, in the present embodiment, the mounting directions of the spring seats 32 of two adjacent spool assemblies are different.
The embodiment also provides the engineering machinery, which comprises the engineering machinery hydraulic control system. Referring to fig. 4, which shows a relationship curve between the spool stroke and the secondary pressure of the adjacent spool assembly of the pilot control valve according to the present embodiment, it can be seen from fig. 4 that, when the construction machine using the above-described pilot control valve 400 is operated, the initial secondary pressure of the pilot control valve 400 can be kept unchanged by the abutment of the upper stopper 313 with the stopper fitting portion 312 at the lower end of the carrier rod 31, the left-hand curve in fig. 4 shows a relationship curve between the spool stroke and the secondary pressure when the spring seat is reversely mounted, and the right-hand curve in fig. 4 shows a relationship curve between the spool stroke and the secondary pressure when the spring seat is normally mounted. According to the attached drawing 4, the spring seat 32 is installed in the positive and negative directions, so that when the handle assembly rotates at the same angle, the stroke of the valve core 33 is different, and the change of the secondary pressure is different when the valve core 33 has the same stroke, the change of the fine adjustment characteristic of the hydraulic system is realized, and the fine adjustment characteristic of the hydraulic system can be adjusted according to the requirements of different users on the operation speed and the comfort.
Fig. 5 shows a relationship curve between the spool stroke and the secondary pressure of the adjacent spool assemblies of the pilot control valve when the thicknesses of the second stroke adjusting members in the vertical direction are different, and as can be seen from fig. 5, by changing the thickness of the second stroke adjusting member 36 in the vertical direction and changing the stroke change of the spool 33, multi-stage adjustment of the flow characteristics between the handle assembly stroke and the main control valve 500 is realized to meet the requirements of different users.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Claims (10)
1. A pilot control valve comprises a valve body and at least two valve core assemblies, wherein the valve body is provided with oil inlet holes, pressure cavities in one-to-one correspondence with the valve core assemblies and oil outlet holes in one-to-one correspondence with the pressure cavities, and the valve core assemblies are used for controlling the oil inlet holes to be selectively communicated or disconnected with the corresponding oil outlet holes through the pressure cavities;
the spool assembly includes:
the piston unit is arranged in the pressure cavity in a sliding manner;
a return spring (34), the return spring (34) being configured to cause the piston unit to have a tendency to move upwards;
a universal assembly (2) and a handle assembly which can rotate relative to the piston unit through the universal assembly (2) to drive the piston unit to move downwards;
the valve body is provided with an upper limiting piece (313) for limiting the limit position when the piston unit moves upwards and a lower limiting piece for limiting the limit position when the piston unit moves downwards;
the device is characterized in that the piston unit is connected with a first stroke adjusting piece and used for adjusting the maximum stroke of the piston unit from the limit position when the piston unit moves upwards to the limit position when the piston unit moves downwards.
2. The pilot control valve of claim 1, wherein the piston unit comprises:
the ejector rod (31) is arranged in the pressure cavity in a sliding manner;
the spring seat (32) is arranged in the pressure cavity in a sliding mode, the spring seat (32) is located below the ejector rod (31) and is abutted to the ejector rod (31) in the vertical direction, the first stroke adjusting piece is connected to the spring seat (32), a reset limiting surface located below the spring seat (32) is arranged on the inner wall of the valve body, and the reset spring (34) is clamped between the spring seat (32) and the reset limiting surface;
the valve core (33), the valve core (33) penetrates the spring seat (32), and the ejector rod (31) can slide or be fixed relative to the valve core (33) along the vertical direction;
the outer peripheral wall of the valve core (33) is provided with a spring limiting surface located below the spring seat (32), and a pressure reducing spring (35) is clamped between the spring seat (32) and the spring limiting surface.
3. The pilot control valve according to claim 2, wherein the first stroke adjusting member is a boss (321) provided on upper and lower sides of the spring seat (32), and the bosses (321) on the upper and lower sides of the spring seat (32) are different in length in a vertical direction;
the bosses (321) on either side of the spring seat (32) can be abutted against the lower limit piece.
4. The pilot control valve according to claim 3, wherein the valve body is provided with an escape space (314) for accommodating the boss (321) above the spring seat (32).
5. The pilot control valve of claim 2, wherein the pilot control valve (400) further comprises a second stroke adjuster (36), the second stroke adjuster (36) being adjustable in thickness in a vertical direction;
the second stroke adjusting piece (36) is connected to one of the lower end of the ejector rod (31) and the upper end of the valve core (33), and the second stroke adjusting piece (36) is selectively abutted with the other in the vertical direction or separated to enable the ejector rod (31) to move downwards relative to the valve core (33) when the piston unit is at the limit position when moving upwards.
6. The pilot control valve according to claim 5, wherein the lower end of the push rod (31) is provided with a downward-opening sliding groove (311), and the upper end of the valve core (33) is convexly provided with a sliding convex part (331) which is in sliding fit with the sliding groove (311) along the vertical direction;
the second stroke adjusting member (36) is connected to the sliding protrusion (331) and interposed between an inner bottom wall of the sliding groove (311) and an upper end surface of the sliding protrusion (331).
7. The pilot control valve according to claim 2, wherein the lower end of the carrier rod (31) is provided with a limit engagement portion (312) located below the upper limit stopper (313), and the limit engagement portion (312) is capable of abutting against the upper limit stopper (313).
8. A hydraulic control system for a working machine, characterized by comprising a pilot control valve (400) according to any one of claims 1 to 7, and
an oil supply unit and a working cylinder (600);
the oil supply unit can control the piston rod of the working oil cylinder (600) to stretch and retract through the main control valve (500), and the main control valve (500) is a hydraulic control valve;
the oil inlet hole of the pilot control valve (400) can be selectively communicated with the oil outlet of the oil supply unit or the hydraulic oil tank (700) through the unlocking solenoid valve (300), and the oil outlet hole of the pilot control valve (400) is communicated with the hydraulic control end of the main control valve (500).
9. The hydraulic control system of engineering machinery according to claim 8, wherein an outlet of the oil supply unit is connected with an inlet of the unlocking solenoid valve (300) through a control oil path, and the control oil path is provided with a check valve (900) and an accumulator (800) which are sequentially arranged along the flow direction of oil therein.
10. A working machine comprising a working machine hydraulic control system according to claim 8 or 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111392475.6A CN114060345A (en) | 2021-11-23 | 2021-11-23 | Pilot control valve, engineering machinery hydraulic control system and engineering machinery |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111392475.6A CN114060345A (en) | 2021-11-23 | 2021-11-23 | Pilot control valve, engineering machinery hydraulic control system and engineering machinery |
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| CN114060345A true CN114060345A (en) | 2022-02-18 |
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| CN202111392475.6A Pending CN114060345A (en) | 2021-11-23 | 2021-11-23 | Pilot control valve, engineering machinery hydraulic control system and engineering machinery |
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| JP2019074188A (en) * | 2017-10-19 | 2019-05-16 | コベルコ建機株式会社 | Construction machine |
| CN211550126U (en) * | 2019-11-27 | 2020-09-22 | 江苏恒立液压科技有限公司 | Signal generating device and remote control device |
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| FR2835574A1 (en) * | 2002-02-04 | 2003-08-08 | Mannesmann Rexroth Sa | Hydraulic remote control unit pressure regulator has compensating chamber at one end of distribution channel connected to controller |
| DE102010006196A1 (en) * | 2010-01-29 | 2011-08-04 | Robert Bosch GmbH, 70469 | Hydraulic pilot control unit |
| CN101846111A (en) * | 2010-06-10 | 2010-09-29 | 江苏鼎晟液压有限公司 | Pilot proportional multi-path reversing valve |
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