CN109899333B - Valve block, hydraulic control system and vehicle - Google Patents
Valve block, hydraulic control system and vehicle Download PDFInfo
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- CN109899333B CN109899333B CN201910248288.7A CN201910248288A CN109899333B CN 109899333 B CN109899333 B CN 109899333B CN 201910248288 A CN201910248288 A CN 201910248288A CN 109899333 B CN109899333 B CN 109899333B
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Abstract
The invention discloses a valve block, a hydraulic control system and a vehicle, and belongs to the technical field of hydraulic control. The valve block comprises an oil inlet P, a first throttling element, a second throttling element, a first reversing valve and a second reversing valve, wherein the oil inlet P is used for being communicated with an oil supplementing pump driven by an engine, inlets of the first throttling element and the second throttling element are communicated with the oil inlet P, outlets of the first reversing valve and the second reversing valve are respectively communicated with two ends of a variable cylinder used for adjusting the angle of a swash plate of a plunger pump, an inlet of the first reversing valve is configured to be communicated with an outlet of the first throttling element in a first state and communicated with an outlet of the second throttling element in a second state, and an inlet of the second reversing valve is configured to be communicated with an outlet of the second throttling element in the first state and communicated with an outlet of the first throttling element in the second state. The valve block and the hydraulic control system can realize the related control of the engine speed and the pump displacement, have simple structure and can be combined with other hydraulic control controllers for use.
Description
Technical Field
The invention relates to the technical field of hydraulic control, in particular to a valve block, a hydraulic control system and a vehicle.
Background
CA control is an automatic control method related to the engine speed, and the control pressure generated by a CA-built control pressure circuit is proportional to the engine speed and is applicable to a vehicle traveling system. The advancing or retreating direction of the vehicle is controlled by the switch electromagnet, the CA control pressure enters the main pump variable control system through the switch electromagnet, and the proportional displacement control of the main pump in the two directions can be realized. I.e., the higher the engine speed, the greater the main pump displacement. Meanwhile, the CA controls the built-in mechanical engine flameout prevention control loop, and when the absorbed power of the system reaches a set value, the swash plate of the main pump swings back to reduce the flow of the system, so that the overload phenomenon of the engine is prevented. The CA control mode can form a system with a quantitative variable and high-pressure feedback motor or a variable motor with pressure feedback, and the system can realize multiple functions and control modes through modular design.
However, the existing CA controller is externally arranged on the plunger pump, can only realize the pure proportional control of the engine and the pump displacement, cannot be used in combination with other liquid controllers, and has limited application range.
Disclosure of Invention
The invention aims to provide a valve block, a hydraulic control system and a vehicle, which can realize the control of the relative speed of an engine and the displacement of a pump and have wide application range.
To achieve the purpose, on one hand, the invention adopts the following technical scheme:
a valve block, comprising:
an oil inlet P for communicating with an oil replenishing pump driven by an engine;
a first throttling element, wherein an inlet of the first throttling element is communicated with the oil inlet P;
a second throttling element, an inlet of which is communicated with the oil inlet P, and an outlet pressure of which is lower than that of the first throttling element;
a first direction valve having an outlet for communicating with a first end for a variable cylinder for adjusting a swash plate angle of the plunger pump, an inlet of the first direction valve being configured to communicate with an outlet of the first throttling element in a first state and communicate with an outlet of the second throttling element in a second state; and
and a second direction valve having an outlet for communicating with the second end of the variable cylinder, the inlet of the second direction valve being configured to communicate with the outlet of the second throttling element in the first state and with the outlet of the first throttling element in the second state.
In one embodiment, the valve block further comprises: and the inlet of the third throttling element is communicated with the oil inlet P, and the outlet of the third throttling element is communicated with an oil supplementing port of the plunger pump.
In one embodiment, the inlet of the second throttling element communicates with the outlet of the third throttling element.
In one embodiment, the valve further comprises a one-way valve disposed between the first direction valve and the second direction valve, the one-way valve configured to allow fluid to flow only from the second direction valve to the first direction valve.
In one embodiment, a first relief valve is provided between the outlet of the first throttling element and the inlet of the second throttling element.
In one embodiment, a second relief valve is further included in communication with the oil inlet P.
In one embodiment, the first and/or second throttling element is a variable throttling aperture throttling element.
In one embodiment, the third throttling element is a variable throttling aperture throttling element.
In one embodiment, the first and second directional valves are both two-position, three-way valves.
In one embodiment, the valve block is a valve block for a vehicle.
On the other hand, the invention adopts the following technical scheme:
a hydraulic control system comprises an engine, an oil replenishing pump, a plunger pump and any one of the valve blocks.
On the other hand, the invention adopts the following technical scheme:
a vehicle comprises the hydraulic control system.
The invention has the following beneficial effects:
according to the valve block, the hydraulic control system and the vehicle, when the rotating speed of an engine is increased, the hydraulic oil quantity of the oil supplementing pump is large, the flow entering the high-pressure end of the variable cylinder from the reversing valve is increased, the action of the variable cylinder is increased, and therefore the displacement of the plunger pump is increased; on the contrary, when the engine speed is slow, the displacement of the plunger pump is reduced, the proportional relation between the engine speed and the pump displacement is realized, and the related control between the engine speed and the pump displacement is realized; the forward or reverse oil supply of the plunger pump is controlled by reversing the first reversing valve and the second reversing valve, so that the traveling direction of the vehicle is controlled; meanwhile, the valve block is simple in structure and low in cost, can be used in combination with other hydraulic controllers, achieves combination of multiple functions and control modes, improves control performance of the pump, and is wide in application range.
Drawings
FIG. 1 is a schematic diagram of a hydraulic control system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a variable displacement cylinder according to an embodiment of the present invention;
FIG. 3 is a schematic structural view of a valve block in a first state according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a valve block in a second state according to an embodiment of the present invention.
Reference numerals:
100. an oil replenishing pump; 200. a valve block; 300. a plunger pump; 400. a variable cylinder;
210. a first throttling element; 220. a second throttling element; 230. a third throttling element; 240. a first direction changing valve; 250. a second directional control valve; 260. a one-way valve; 270. a first overflow valve; 280. a second overflow valve; 410. a cylinder body; 420. a piston; 430. an elastic member; 411. a first end of a variable cylinder; 412. and a second end of the variable cylinder.
Detailed Description
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those 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, are not to be construed as limiting the present invention.
The embodiment of the invention provides a hydraulic control system and a vehicle adopting the hydraulic control system, so as to realize the relevant control of the engine speed and the pump displacement. As shown in fig. 1, the hydraulic control system includes an engine (not shown), a charge oil pump 100, a valve block 200, a plunger pump 300, and a variable cylinder 400. The engine drives the oil replenishing pump 100 to pump oil, the variable cylinder 400 is used for adjusting the swash plate angle of the plunger pump 300, and the oil replenishing pump 100 adjusts the output of the variable cylinder 400 through the valve block 200 so as to adjust the displacement of the plunger pump 300.
Alternatively, as shown in fig. 2, the variable cylinder 400 includes a cylinder block 410 and a piston 420 disposed in the cylinder block 410, both ends of the variable cylinder 400 (i.e., a first end 411 of the variable cylinder and a second end 412 of the variable cylinder) are respectively provided with hydraulic ports communicating with both end surfaces of the piston 420, and the piston 420 is directly or indirectly connected to the swash plate. Optionally, elastic members 430 are disposed between both sides of the piston 420 and the cylinder 410, and the elastic members on both sides of the piston 420 preferably provide equal elastic force to the piston 420. The valve block 200 is used to adjust the position of the piston 420 of the variable cylinder 400 and thus the angle of the swash plate. The cylinder 410 may, but is not limited to, include two cylinder units, two ends of the piston 420 are respectively sealed and fitted in the two cylinder units, and the two cylinder units are respectively provided with hydraulic oil ports communicated with two end surfaces of the piston 420.
As shown in fig. 3 and 4, the valve block 200 includes an oil inlet P, a first throttling element 210, a second throttling element 220, a third throttling element 230, a first direction changing valve 240, and a second direction changing valve 250. The oil inlet P is used for communicating with the oil replenishing pump 100, inlets of the first throttling element 210, the second throttling element 220 and the third throttling element 230 are all communicated with the oil inlet P, an outlet of the third throttling element 230 is communicated with an oil replenishing port of the plunger pump 300 so as to replenish oil to the plunger pump 300 under the condition that hydraulic oil leaks from the plunger pump 300 (the trend of the oil in the oil replenishing port from the third throttling element 230 to the plunger pump 300 is indicated by an arrow at the downstream of F in fig. 1), and the outlet pressure of the second throttling element 220 is lower than the outlet pressure of the first throttling element 210. A third relief valve may be provided between the third throttling element 230 and the oil supply port of the plunger pump 300, but is not limited thereto. The outlet a of the first direction valve 240 communicates with the first end 411 of the variable cylinder 400, and the outlet B of the second direction valve 250 communicates with the second end 412 of the variable cylinder 400. The valve block 200 includes a first state in which an inlet of the first direction valve 240 communicates with an outlet of the first throttling element 210 and an inlet of the second direction valve 250 communicates with an outlet of the second throttling element 220, so that the pressure of the first end 411 of the variable cylinder 400 is greater than the pressure of the second end 412 of the variable cylinder 400, and at this time, the plunger pump 300 supplies oil in a forward direction and the motor driven by the plunger pump 300 rotates in a forward direction, that is, the motor rotates in a direction to advance the vehicle; in the second state, the inlet of the first direction valve 240 communicates with the outlet of the second throttling element 220, and the inlet of the second direction valve 250 communicates with the outlet of the first throttling element 210, so that the pressure at the second end 412 of the variable cylinder 400 is greater than the pressure at the first end 411 of the variable cylinder 400, at which time the plunger pump 300 supplies oil in a reverse direction, and the motor driven by the plunger pump 300 rotates in a reverse direction, that is, the motor rotates in a direction to move the vehicle backward.
Wherein the first direction valve 240 and the second direction valve 250 are preferably, but not limited to, two-position three-way direction valves. Specifically, the two inlets of the first direction valve 240 are a first inlet and a second inlet, respectively, and the inlet of the second direction valve 250 is a third inlet and a fourth inlet, respectively. In the first state, the first inlet is communicated with the outlet of the first throttling element 210, and the third inlet is communicated with the outlet of the second throttling element 220; in the second state, the fourth inlet communicates with the outlet of the first throttling element 210 and the second inlet communicates with the outlet of the second throttling element 220.
In the valve block 200 provided in this embodiment, when the engine speed is increased, the amount of hydraulic oil in the oil supply pump 100 is large, and the flow entering the high-pressure end of the variable cylinder 400 from the directional valve is increased, so that the movement of the variable cylinder 400 is increased, and the inclination angle of the swash plate is affected, thereby increasing the displacement of the plunger pump 300; on the contrary, when the engine speed is slow, the displacement of the plunger pump 300 is reduced, the proportional relation between the engine speed and the pump displacement is realized, and the related control between the engine speed and the pump displacement is realized; the forward or reverse oil supply of the plunger pump 300 is controlled by reversing the first reversing valve 240 and the second reversing valve 250, so that the vehicle running direction is controlled; meanwhile, the valve block 200 is simple in structure and low in cost, can be used in combination with other hydraulic controllers, achieves combination of multiple functions and control modes, improves control performance of the pump, and is wide in application range.
As shown in fig. 3 and 4, the inlet of the second throttling element 220 communicates with the outlet of the third throttling element 230, which facilitates the outlet pressure of the second throttling element 220 to be lower than the outlet pressure of the first throttling element 210 by throttling twice, and simplifies the structure of the valve block 200. In other embodiments, the inlet of the second throttling element 220 may be directly communicated with the oil inlet P, so that the outlet pressure of the second throttling element 220 is ensured to be lower than the outlet pressure of the first throttling element 210.
To facilitate regulation of the pressure at the outlet of the first throttling element 210 and the outlet of the second throttling element 220, at least one of the first throttling element 210, the second throttling element 220 and the third throttling element 230 is a variable throttling aperture throttling element. For example, a movable flap may be provided at the orifice of at least one of the first throttling element 210, the second throttling element 220 and the third throttling element 230, and the position of the flap is moved to adjust the area of the orifice covered by the flap, thereby adjusting the orifice diameter. Of course, other known variable restriction orifice members may be used.
If the oil pipe is broken at the outlet a of the first direction valve 240, the first end 411 of the variable cylinder 400 loses oil pressure, and the second end 412 of the variable cylinder 400 is normally supplied with oil, which causes the plunger pump 300 to supply oil reversely. In order to solve the problem that the vehicle using the hydraulic control system may suddenly run backward from the normal running, which is dangerous, the valve block 200 further includes a check valve 260 disposed between the first direction changing valve 240 and the second direction changing valve 250, and the check valve 260 is configured such that fluid can only flow from the second direction changing valve 250 to the first direction changing valve 240. If the oil pipe at the outlet a of the first reversing valve 240 is broken, the check valve 260 is opened, and a part of oil originally flowing from the second throttle hole to the second reversing valve 250 is guided into the first reversing valve 240, so that the pressure values at the outlets of the first reversing valve 240 and the second reversing valve 250 are equal, that is, the pressure values at the two ends of the variable cylinder 400 are equal, at this time, the angle of the swash plate of the plunger pump 300 is approximately zero, the plunger pump 300 has no variable, the vehicle stops moving, and the driving safety is ensured.
When the engine power is high and the rotation speed of the oil replenishment pump 100 is high, the pressure difference between the outlet of the first throttling element 210 and the outlet of the second throttling element 220 is large, and the pressure difference between both sides of the variable cylinder 400 is large, which results in a high displacement of the plunger pump 300. In order to control the displacement, a first overflow valve 270 is arranged between the outlet of the first throttling element 210 and the inlet of the second throttling element 220, when the pressure difference between the outlet of the first throttling element 210 and the inlet of the second throttling element 220 is higher than a preset value, the first overflow valve 270 is opened, part of oil flows to the second throttling element 220 from the first throttling element 210, the pressure difference between the two sides of the variable cylinder 400 is reduced, and the displacement of the plunger pump 300 is further ensured not to be too large.
In winter and other low-temperature environments, when the vehicle is started, the viscosity of hydraulic oil is high, so that the pressure at the throttling element is possibly too high, and the safety of the whole system is influenced. To solve this problem, optionally, the valve block 200 further includes a second overflow valve 280 communicated with the oil inlet P, and when the system pressure is too high, the second overflow valve 280 is opened to overflow the oil into an oil return tank or other container, so that the system pressure is no longer increased to avoid pressure overload and protect the system.
The operation of the hydraulic control system according to the present embodiment will be briefly described with reference to fig. 1 to 4:
when the vehicle is normally running forward, as shown in fig. 1 to 3, the first direction valve 240 is energized, the second direction valve 250 is de-energized, the first inlet port is communicated with the outlet port of the first throttling element 210, and the third inlet port is communicated with the outlet port of the second throttling element 220, i.e., the valve block 200 is in the first state. The oil at the oil inlet P of the valve block 200 is divided into two paths, one path passes through the first throttling element 210 and the outlet a of the first reversing valve 240 and then enters the first end 411 of the variable cylinder 400; the other path enters the third throttling element 230, the oil flowing out from the third throttling element 230 is divided into two paths, one path enters an oil supplementing port of the plunger pump 300 under the condition that the plunger pump 300 leaks hydraulic oil and the like, the other path enters the second end 412 of the variable cylinder 400 through the second throttling element 220 and the outlet B of the second reversing valve 250, as the large pressure at the outlet of the first throttling element 210 is greater than the pressure at the outlet of the second throttling element 220, the oil pressure at the first end 411 of the variable cylinder 400 is greater than the oil pressure at the second end 412 of the variable cylinder 400, and the plunger pump 300 supplies oil in the forward direction, so that the motor drives the vehicle to move forwards. Also, the displacement of the plunger pump 300 and thus the operating speed of the vehicle may be adjusted by controlling the rotational speed of the engine.
When the vehicle is moving backwards, as shown in fig. 4, the first direction valve 240 is de-energized, the second direction valve 250 is energized, the fourth inlet port is in communication with the outlet port of the first throttling element 210, and the second inlet port is in communication with the outlet port of the second throttling element 220, i.e., the valve block 200 is in the second state. The oil at the oil inlet P of the valve block 200 is divided into two paths, and one path enters the second end 412 of the variable cylinder 400 after passing through the first throttling element 210 and the outlet B of the second reversing valve 250; the other path enters the third throttling element 230, the oil flowing out from the third throttling element 230 is divided into two paths, one path enters the oil supplementing port of the plunger pump 300 under the condition that the plunger pump 300 has hydraulic oil leakage and the like, the other path enters the first end 411 of the variable cylinder 400 through the second throttling element 220 and the outlet A of the first reversing valve 240, and the plunger pump 300 reversely supplies oil because the large pressure at the outlet of the first throttling element 210 is greater than the pressure at the outlet of the second throttling element 220, the oil pressure at the second end 412 of the variable cylinder 400 is greater than the oil pressure at the first end 411 thereof, so that the motor drives the vehicle to retreat. Also, the displacement of the plunger pump 300 and thus the operating speed of the vehicle may be adjusted by controlling the rotational speed of the engine.
The technical principle of the present invention is described above in connection with specific embodiments. The description is made for the purpose of illustrating the principles of the invention and should not be construed in any way as limiting the scope of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without inventive effort, which would fall within the scope of the present invention.
Claims (10)
1. A valve block comprising an oil inlet P for communication with an oil replenishment pump (100) driven by an engine, characterized in that it further comprises:
a first throttling element (210) having an inlet communicating with the oil inlet P;
a second throttling element (220) having an inlet communicating with the oil inlet P and an outlet pressure lower than an outlet pressure of the first throttling element (210);
a first direction valve (240) having an outlet a for communication with a first end (411) of a variable cylinder (400), the variable cylinder (400) for adjusting a swash plate angle of a plunger pump (300), an inlet of the first direction valve (240) being configured to communicate with an outlet of a first throttling element (210) in a first state and with an outlet of a second throttling element (220) in a second state; and
a second direction valve (250) having an outlet B for communication with the second end (412) of the variable cylinder (400), the inlet of the second direction valve (250) being configured to communicate with the outlet of the second throttling element (220) in the first state and with the outlet of the first throttling element (210) in the second state.
2. The valve block of claim 1, further comprising:
a third throttling element (230) with an inlet in communication with the oil inlet P and an outlet for communication with an oil replenishment port of the plunger pump (300).
3. Valve block according to claim 2, characterized in that the inlet of the second throttling element (220) communicates with the outlet of the third throttling element (230).
4. The valve block according to any of claims 1 to 3, further comprising a one-way valve (260) disposed between the first direction valve (240) and the second direction valve (250), the one-way valve (260) configured such that fluid can only flow from the second direction valve (250) to the first direction valve (240).
5. A valve block according to any one of claims 1 to 3, characterised in that a first relief valve (270) is provided between the outlet of the first throttling element (210) and the inlet of the second throttling element (220).
6. A valve block according to any one of claims 1 to 3, further comprising a second spill valve (280) communicating with the oil inlet P.
7. Valve block according to claim 2 or 3, characterized in that the first throttle element (210), the second throttle element (220) and/or the third throttle element (230) are throttle elements with variable throttle bore diameters.
8. A valve block according to any one of claims 1 to 3, characterized in that the first direction valve (240) and the second direction valve (250) are both two-position three-way valves.
9. A hydraulic control system, comprising an engine, a make-up oil pump (100), a plunger pump (300) and a valve block (200) according to any one of claims 1 to 8.
10. A vehicle characterized by comprising the hydraulic control system of claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910248288.7A CN109899333B (en) | 2019-03-29 | 2019-03-29 | Valve block, hydraulic control system and vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910248288.7A CN109899333B (en) | 2019-03-29 | 2019-03-29 | Valve block, hydraulic control system and vehicle |
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| CN109899333A CN109899333A (en) | 2019-06-18 |
| CN109899333B true CN109899333B (en) | 2020-06-02 |
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| CN201910248288.7A Active CN109899333B (en) | 2019-03-29 | 2019-03-29 | Valve block, hydraulic control system and vehicle |
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| CN112727814B (en) * | 2020-12-28 | 2022-06-28 | 浙江大学 | Variable-speed and variable-displacement single-rod electro-hydraulic actuator |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2208172C3 (en) * | 1972-02-22 | 1974-07-11 | Karl Dipl.-Ing. 7024 Bernhausen Schlecht | Device for damping the load-related pressure increase in hydrostatic drives |
| CN2116797U (en) * | 1992-03-21 | 1992-09-23 | 建设部长沙建筑机械研究所 | Novel closed oil circuit hydraulic control device |
| CN102275223B (en) * | 2011-09-20 | 2013-04-10 | 四川大学 | Novel rotation driving system for mixing drum of concrete mixing transport vehicle |
| CN203684314U (en) * | 2013-12-30 | 2014-07-02 | 华侨大学 | Load-sensitive excavator negative flow system |
| CN104061212B (en) * | 2014-06-06 | 2017-01-25 | 中国煤炭科工集团太原研究院有限公司 | Electric hydraulic control running system for bracket carrier |
| CN205136169U (en) * | 2015-10-17 | 2016-04-06 | 潍柴动力股份有限公司 | Hydraulic pressure traveling system by motor speed controller |
| CN205225909U (en) * | 2015-11-04 | 2016-05-11 | 潍柴动力股份有限公司 | All -hydraulic travel drive system |
| CN206830550U (en) * | 2017-03-07 | 2018-01-02 | 佛山市科达液压机械有限公司 | The open type pump that can reversely export |
| CN107906064A (en) * | 2017-12-25 | 2018-04-13 | 邵阳维克液压股份有限公司 | The device and variable method for control speed of changeable constant pressure variable displacement pump variable speed |
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