CN108978772B - Load-sensitive steering hydraulic system and loader - Google Patents
Load-sensitive steering hydraulic system and loader Download PDFInfo
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- CN108978772B CN108978772B CN201810800444.1A CN201810800444A CN108978772B CN 108978772 B CN108978772 B CN 108978772B CN 201810800444 A CN201810800444 A CN 201810800444A CN 108978772 B CN108978772 B CN 108978772B
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- 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
- E02F9/225—Control of steering, e.g. for hydraulic motors driving the vehicle tracks
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- 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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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Fluid-Pressure Circuits (AREA)
- Operation Control Of Excavators (AREA)
Abstract
The invention relates to a load-sensitive steering hydraulic system, which aims to solve the problem that the steering process of the existing load-sensitive steering hydraulic system is not smooth; the utility model provides a load sensitive steering hydraulic system, including steering cylinder, the flow amplification valve who is connected with steering cylinder, the steering gear who is connected with the flow amplification valve, the hydraulic tank, be connected with the hydraulic tank and to the plunger pump of flow amplification valve fuel feeding, external control formula overflow valve, the LS mouth of steering gear is connected with the external control end of external control formula overflow valve, the LS mouth of external control formula overflow valve is connected with the LS mouth of plunger pump through the pipeline in the oil inlet of external control formula overflow valve, the oil-out of external control formula overflow valve is connected with the hydraulic tank through the pipeline. The invention has the advantages that the external control overflow valve arranged on the pump control pipeline can effectively weaken or even eliminate the pressure fluctuation or sudden change of a load signal transmitted to the pump by the steering gear, thereby solving the problem of instant whole machine shaking caused by sudden and rapid starting or stopping of the steering of the loader, obviously improving the smoothness in the steering process of the whole machine and improving the steering comfort of the loader.
Description
Technical Field
The invention relates to a steering hydraulic system, in particular to a load-sensitive steering hydraulic system and a loader.
Background
At present, the common hydraulic systems of the loader comprise a fixed-quantity hydraulic system, a fixed-quantity and variable-quantity hydraulic system and a full-quantity and variable-quantity hydraulic system. Because the quantitative hydraulic system has higher overflow loss, the high-end loader mostly adopts energy-saving hydraulic systems such as a quantitative variable hydraulic system or a full variable hydraulic system, and the steering hydraulic systems of the quantitative variable hydraulic system and the full variable hydraulic system are load-sensitive control hydraulic systems. In a traditional load-sensitive control steering hydraulic system, load signals are directly transmitted to a plunger pump by a steering gear, and the change of the load signals can control the change of the displacement of the plunger pump, so that oil supply of the plunger pump is realized as required.
In the existing load-sensitive steering hydraulic system, a load signal of a steering gear is directly transmitted to a plunger pump, which causes certain problems of the machine, for example, when a steering wheel is suddenly and quickly started or stops rotating, the load signal is suddenly changed, the displacement of the piston pump is also changed violently after the load signal with violent change is transmitted to the plunger pump, so that the pressure fluctuation and the impact of the hydraulic system are caused, the performance of the machine is the moment of suddenly and quickly starting or stopping steering, and the whole machine shakes violently; in addition, when a driver rotates a steering wheel, the change of the rotating speed can also cause the instability of a load signal output by the steering gear, a fluctuating load signal is transmitted to the plunger pump, the displacement of the plunger pump is also unstable, and the plunger pump cannot output constant flow to the steering hydraulic system, so that the phenomenon of irregularity occurs in the steering process of the loader.
Disclosure of Invention
The invention aims to solve the technical problem that the steering process of the conventional load-sensitive steering hydraulic system is not smooth, and provides a load-sensitive steering hydraulic system and a loader.
The technical scheme for realizing the purpose of the invention is as follows: the load-sensitive steering hydraulic system is characterized by further comprising an external control overflow valve, an LS port of the steering gear is connected with an external control end of the external control overflow valve, an oil inlet of the external control overflow valve is connected with the LS port of the plunger pump through a pipeline, and an oil outlet of the external control overflow valve is connected with the hydraulic oil tank through a pipeline.
In the invention, the external control overflow valve plays a role in duplicating a load signal of the steering gear, and the load signal of the steering gear is not directly fed back to the plunger pump, but is duplicated and then transmitted to the plunger pump through the external control overflow valve. The external control overflow valve can effectively weaken and even eliminate pressure fluctuation or sudden change of a load signal transmitted to the plunger pump by the steering gear, so that the problem of instant whole machine shaking when the loader is suddenly and quickly started or stopped to steer is solved, the smoothness of the whole machine in the steering process can be obviously improved, and the steering comfort of the loader is improved.
Further, the load-sensitive steering hydraulic system further comprises a first throttle valve, and the first throttle valve is arranged on a pipeline between an oil inlet of the external control type overflow valve and the LS port of the plunger pump.
Furthermore, the load-sensitive steering hydraulic system further comprises a one-way damping valve, the one-way damping valve is connected to an oil path between the first throttling valve and the LS port of the plunger pump, the one-way valve is connected with the damping valve in parallel, and the one-way valve is communicated in one way in the direction of the LS port of the plunger pump.
Furthermore, the load-sensitive steering hydraulic system further comprises a priority valve, a shuttle valve and a working hydraulic system to form a confluence hydraulic system of the steering hydraulic system and the working system, wherein an oil inlet of the priority valve is connected with an oil outlet of the plunger pump, and a CF oil port of the priority valve is connected with an oil inlet of the flow amplifying valve; the LS port of the priority valve is connected with an oil inlet of the external control type overflow valve through a first throttling valve, or is directly connected with the LS port of the steering gear through a pipeline, or is connected with the oil inlet of the external control type overflow valve through a pipeline; the shuttle valve is connected to a pipeline between the first throttling valve and the LS port of the plunger pump, one oil inlet of the shuttle valve is connected with the oil outlet end of the first throttling valve, the oil outlet end of the shuttle valve is connected with the LS port of the plunger pump, and at the moment, the one-way damping valve is connected to an oil path between the oil outlet end of the shuttle valve and the LS port of the plunger pump. And the EF oil port of the priority valve is connected with a confluence oil supply port of a working hydraulic system, and the other oil inlet end of the shuttle valve is connected with a load signal output end of the working hydraulic system.
Further, the load-sensitive steering hydraulic system further comprises a second throttle valve, and the second throttle valve is arranged on a pipeline between an oil outlet of the external control type overflow valve and the hydraulic oil tank.
The technical scheme for realizing the purpose of the invention is as follows: a loader is disclosed that includes the aforementioned load-sensitive steering hydraulic system.
Compared with the prior art, the invention has the advantages that the external control overflow valve arranged on the pump control pipeline can effectively weaken and even eliminate the pressure fluctuation or mutation of the load signal transmitted to the pump by the steering gear, thereby solving the problem of instant whole machine shaking when the loader is suddenly and rapidly started or stopped to steer, obviously improving the smoothness of the whole machine in the steering process and improving the steering comfort of the loader.
Drawings
FIG. 1 is a schematic diagram of the load sensitive steering hydraulic system of the present invention.
FIG. 2 is a schematic diagram of a load sensitive steering hydraulic system in a loader merging with a working hydraulic system.
Part names and serial numbers in the figure:
the hydraulic control system comprises a hydraulic oil tank 1, a plunger pump 2, a priority valve 3, a first throttle valve 4, a second throttle valve 5, a steering gear 6, a steering oil cylinder 7, a flow amplification valve 8, an external control overflow valve 9, a shuttle valve 10, a one-way damping valve 11 and a working hydraulic system 12.
Detailed Description
The following description of the embodiments refers to the accompanying drawings.
The first embodiment.
As shown in fig. 1, the load-sensitive steering hydraulic system of the present invention is an independent steering hydraulic system, and can be used for wheeled vehicles such as loaders. In the embodiment, the load-sensitive steering hydraulic system comprises a hydraulic oil tank 1, a plunger pump 2, a first throttle valve 4, a second throttle valve 5, a steering gear 6, a steering oil cylinder 7, a flow amplifying valve 8, an external control overflow valve 9, a one-way damping valve 11 and the like. An S port of the plunger pump 2 is connected with the hydraulic oil tank 1, a B port of the plunger pump 2 is connected with an oil inlet P port of the flow amplifying valve 8, an A port and a B port of the flow amplifying valve 8 are connected with the steering oil cylinder 7, a T port of the flow amplifying valve 8 is connected with an oil return port of the hydraulic oil tank 1, and a P1 port of the flow amplifying valve 8 is connected with a P port of the steering gear 6; a T port of the steering gear 6 is connected with an oil return port of the hydraulic oil tank 1, an L port of the steering gear 6 is connected with a port a of the flow amplifying valve 8, and an R port of the steering gear 6 is connected with a port b of the flow amplifying valve 8; an external control end d port of the external control type overflow valve 9 is connected with an LS port of the steering gear 6, an oil outlet K port of the external control type overflow valve 9 is connected with an oil return port of the hydraulic oil tank 1 through a second throttling valve 5, an oil inlet C port of the external control type overflow valve 9 is connected with the LS port of the plunger pump 2 through a second throttling valve 4 and a one-way damping valve 11 in sequence, the one-way damping valve 11 is connected on an oil path between the first throttling valve 4 and the LS port of the plunger pump 2, the one-way valve in the one-way damping valve 11 is connected with the damping valve in parallel, and the one-way valve is conducted in one-way in the direction of the LS.
The working process of the transmission system in the embodiment is as follows:
when the loader is in a standby state, the plunger pump 2 sucks oil from the hydraulic oil tank 1 and outputs high-pressure oil from the port B, the high-pressure oil enters the flow amplifying valve 8, the flow amplifying valve 8 is in a middle position function because the machine is in the standby state, the oil cannot enter the steering oil cylinder 7 through the flow amplifying valve 8 because the middle position function of the flow amplifying valve 8 is in a closed middle position, meanwhile, the steering gear 6 is also in a middle position function, the LS port of the steering gear 6 is communicated with the port T, the LS pipeline of the steering gear 6 is in a pressure relief state, the external control port d of the external control type overflow valve 9 is connected with the LS port of the steering gear 6, the pressure value of the external control port d of the external control type overflow valve 9 is small, the LS port of the plunger pump 2 is connected with the oil inlet C of the external control type overflow valve 9 after passing through the one-way damping valve 11 and the first throttle valve 4, and the LS pressure of the plunger pump 2 overcomes the spring force of the external control overflow valve 9 and the external control port, the LS pressure of the plunger pump 2 is communicated with the oil return port of the hydraulic oil tank 1 after passing through the one-way damping valve 11, the first throttle valve 4 and the external control type overflow valve 9, at the moment, the LS pressure of the plunger pump 2 is equal to the spring force of the external control type overflow valve 9 and the pressure of an external control end d port of the external control type overflow valve 9, the LS pressure of the plunger pump 2 is small due to the fact that the spring force of the external control type overflow valve 9 is small, the displacement of the plunger pump 2 is automatically adjusted to the minimum displacement, and the flow output by the plunger pump 2 is only the leakage amount of a maintenance pipeline system at the moment.
When the loader turns, the steering gear 6 works at the left functional position or the right functional position, at the moment, the LS port of the steering gear 6 outputs load signal pressure, the pressure acts on the external control port d of the external control overflow valve 9, because the pressure of the external control port d is higher than that of the port C of the oil inlet, the opening degree of the valve core of the external control type overflow valve 9 is reduced, so that the pressure of the oil inlet C opening of the external control type overflow valve 9 is increased, the pressure of the oil inlet C opening of the external control type overflow valve 9 is equal to the load signal pressure of the steering gear 6 plus the spring force of the external control type overflow valve 9, because the spring force is very small, the pressure of the port C of the oil inlet of the external control type overflow valve 9 can be equivalently considered to be equal to the load signal pressure output by the steering gear 6, the port C of the oil inlet of the external control type overflow valve 9 is connected with the LS port of the plunger pump 2 through the first throttle valve 4 and the one-way damping valve 11, namely, the external control overflow valve 9 copies the load signal of the steering gear 6 and transmits the load signal to the LS port of the plunger pump 2. At this time, because the LS port pressure of the plunger pump 2 rises, the output displacement of the plunger pump 2 increases, the high-pressure oil output by the plunger pump 2 enters the flow amplifying valve 8, and because the steering gear 6 rotates, the L or R port of the steering gear 6 outputs pilot oil to push the main valve rod of the flow amplifying valve 8 to act on the left or right functional position, the oil enters the steering cylinder 7 through the left or right functional position of the flow amplifying valve 8, and the steering of the whole machine is realized.
When the rotating speed of the steering wheel is increased, the pressure of a load signal output by the steering gear 6 is increased, the opening degree of the external control overflow valve 9 is further reduced, the pressure of the LS port of the plunger pump 2 is increased along with the increase of the pressure of the LS port, the displacement of the plunger pump 2 is increased, otherwise, the displacement of the plunger pump 2 is reduced, and oil supply of the plunger pump 2 is realized as required.
Because the load signal of the steering gear 6 acts on the external control end of the external control type overflow valve 9, and the pressure signal received by the plunger pump 2 comes from the oil inlet C port of the external control type overflow valve 9, the signal copying process can weaken and even eliminate the pressure fluctuation and impact of the external control end, so the pressure fluctuation and impact of the load signal of the steering gear 6 can not be directly transmitted to the plunger pump 2, thereby the problems of complete machine shaking and swaying caused by the fluctuation or sudden change of the load signal of the loader are solved, and the steering smoothness of the machine is better.
And a second throttling valve 5 is arranged at an oil outlet K port of the external control type overflow valve 9, and the second throttling valve 5 can improve the oil return back pressure of the external control type overflow valve 9 and control the oil return flow.
Example two.
As shown in fig. 2, compared with the first embodiment, the load-sensitive steering hydraulic system of the loader in the present embodiment can be merged with the working hydraulic system 12 of the loader, so the load-sensitive steering hydraulic system further includes a priority valve 3 and a shuttle valve 10 compared with the first embodiment; an oil outlet B port of the plunger pump 2 is connected with an oil inlet P port of a priority valve, a priority oil supply port CF port of the priority valve 3 is connected with an oil inlet P port of a flow amplifying valve, a surplus flow oil supply port EF port of the priority valve 3 is connected with a confluence port of a distribution valve in a loader working hydraulic system 12, an LS port of the priority valve 3 is connected with an oil inlet C port of an external control type overflow valve 9 through a first throttling valve, the first throttling valve is connected with one oil inlet of a shuttle valve 10, the other oil inlet of the shuttle valve is connected with a load feedback port of the distribution valve in the loader working hydraulic system 12, and an oil outlet of the shuttle valve 10 is connected with a one-way damping valve.
In this embodiment, a second throttle valve 5 is disposed at an oil outlet K of the external control overflow valve 9, and the second throttle valve 5 can improve the oil return back pressure of the external control overflow valve 9 and control the oil return flow. In a standby state, oil output by the plunger pump 2 enters the oil inlet C of the external control overflow valve 9 through the LS port of the priority valve 3 and flows back to the hydraulic oil tank 1 through the oil outlet K port, and if the second throttle valve 5 is not arranged, the plunger pump 2 runs too much through the channel to cause that the displacement of the plunger pump 2 cannot be adjusted to the minimum state, so that great throttling loss is generated.
The first throttling valve 4 is arranged at the port C of the oil inlet of the external control type overflow valve 9, when the loader turns, oil flows back to the hydraulic oil tank 1 through the LS port of the priority valve 3 and the external control type overflow valve 9, when the oil flows through the first throttling valve 4, the first throttling valve 4 can stabilize the flow, the fluctuation effect is weakened, the pressure transmitted to the plunger pump 2 by the external control type overflow valve 9 is further stabilized, and the loader turns more stably.
In this embodiment, the LS port of the priority valve 3 may also be directly connected to the LS port of the steering gear through a pipeline, or may also be directly connected to the port C of the oil inlet of the external control type relief valve 9.
Claims (8)
1. A load-sensitive steering hydraulic system comprises a steering oil cylinder, a flow amplification valve connected with the steering oil cylinder, a steering gear connected with the flow amplification valve, a hydraulic oil tank and a plunger pump connected with the hydraulic oil tank and supplying oil to the flow amplification valve.
2. The load-sensitive steering hydraulic system according to claim 1, further comprising a first throttling valve disposed on a line between an oil inlet of the externally controlled spill valve and an LS port of the plunger pump.
3. The load-sensitive steering hydraulic system according to claim 2, further comprising a one-way damping valve connected in the oil path between the first throttle valve and the LS port of the plunger pump, wherein the one-way damping valve is connected in parallel with the damping valve and the one-way valve is in one-way communication in the direction of the LS port of the plunger pump.
4. The load-sensitive steering hydraulic system according to claim 2, further comprising a priority valve and a shuttle valve, wherein an oil inlet of the priority valve is connected with an oil outlet of the plunger pump, and a CF oil port of the priority valve is connected with an oil inlet of the flow amplifying valve; the LS port of the priority valve is connected with the oil inlet of the external control type overflow valve through a first throttling valve, or the LS port of the priority valve is connected with the LS port of the steering gear, or the LS port of the priority valve is directly connected with the oil inlet of the external control type overflow valve; the shuttle valve is connected to a pipeline between the first throttling valve and the LS opening of the plunger pump, one oil inlet of the shuttle valve is connected with the oil outlet end of the first throttling valve, and the oil outlet end of the shuttle valve is connected with the LS opening of the plunger pump.
5. The load-sensitive steering hydraulic system according to claim 4, further comprising a one-way damping valve connected to an oil path between the oil outlet end of the shuttle valve and the LS port of the plunger pump, wherein the one-way damping valve is connected in parallel with the damping valve and the one-way valve is in one-way communication in the direction of the LS port of the plunger pump.
6. The load-sensitive steering hydraulic system according to claim 4, further comprising a working hydraulic system, wherein the EF oil port of the priority valve is connected with a confluence oil supply port of the working hydraulic system, and the other oil inlet end of the shuttle valve is connected with a load signal output end of the working hydraulic system.
7. The load sensitive steering hydraulic system according to any one of claims 1 to 6, further comprising a second throttle valve provided on a line between an oil outlet of the externally controlled spill valve and a hydraulic oil tank.
8. A loader characterised by comprising a load sensitive steering hydraulic system as claimed in any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810800444.1A CN108978772B (en) | 2018-07-20 | 2018-07-20 | Load-sensitive steering hydraulic system and loader |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810800444.1A CN108978772B (en) | 2018-07-20 | 2018-07-20 | Load-sensitive steering hydraulic system and loader |
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| Publication Number | Publication Date |
|---|---|
| CN108978772A CN108978772A (en) | 2018-12-11 |
| CN108978772B true CN108978772B (en) | 2020-11-20 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201810800444.1A Active CN108978772B (en) | 2018-07-20 | 2018-07-20 | Load-sensitive steering hydraulic system and loader |
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| CN (1) | CN108978772B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20100063939A (en) * | 2008-12-04 | 2010-06-14 | 현대중공업 주식회사 | Skid steer loader flow summation device |
| CN102714979A (en) * | 2012-06-19 | 2012-10-10 | 石河子大学 | Hydraulic system for self-propelled dwarf tree fruit harvester |
| CN104032791A (en) * | 2014-05-28 | 2014-09-10 | 广西柳工机械股份有限公司 | Quantitative and variable hydraulic system of loading machine |
| CN204491707U (en) * | 2014-12-16 | 2015-07-22 | 派克汉尼汾流体传动产品（上海）有限公司 | Loader semi-variety hydraulic system |
| CN106609779A (en) * | 2017-02-08 | 2017-05-03 | 雷沃重工股份有限公司 | Flow amplifying valve and loading machine variable steering hydraulic system |
-
2018
- 2018-07-20 CN CN201810800444.1A patent/CN108978772B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20100063939A (en) * | 2008-12-04 | 2010-06-14 | 현대중공업 주식회사 | Skid steer loader flow summation device |
| CN102714979A (en) * | 2012-06-19 | 2012-10-10 | 石河子大学 | Hydraulic system for self-propelled dwarf tree fruit harvester |
| CN104032791A (en) * | 2014-05-28 | 2014-09-10 | 广西柳工机械股份有限公司 | Quantitative and variable hydraulic system of loading machine |
| CN204491707U (en) * | 2014-12-16 | 2015-07-22 | 派克汉尼汾流体传动产品（上海）有限公司 | Loader semi-variety hydraulic system |
| CN106609779A (en) * | 2017-02-08 | 2017-05-03 | 雷沃重工股份有限公司 | Flow amplifying valve and loading machine variable steering hydraulic system |
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| Publication number | Publication date |
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| CN108978772A (en) | 2018-12-11 |
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