CN107477039B - Hydraulic system with flow compensation function and engineering machinery - Google Patents
Hydraulic system with flow compensation function and engineering machinery Download PDFInfo
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- CN107477039B CN107477039B CN201710690871.4A CN201710690871A CN107477039B CN 107477039 B CN107477039 B CN 107477039B CN 201710690871 A CN201710690871 A CN 201710690871A CN 107477039 B CN107477039 B CN 107477039B
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- valve
- pressure
- compensation
- pressure input
- hydraulic system
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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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
Abstract
The present invention relates to a hydraulic system having a flow compensation function and a construction machine equipped with the hydraulic system, the hydraulic system including: a main pump connected to the oil tank and controlled in a load sensing manner; an actuator; the main control valve is connected with the main pump and the executing mechanism and used for distributing hydraulic oil for the executing mechanism; a pilot pressure input part coupled with the main control valve so as to be able to input a pilot pressure to the main control valve; and the flow compensation mechanism comprises a compensation pressure input part and a flow compensation valve block, wherein the compensation pressure input part is used for inputting constant compensation pressure to the flow compensation valve block, and the flow compensation valve block is respectively connected with the pilot pressure input part, the compensation pressure input part, a load pressure output pipeline of the main control valve and the displacement adjusting mechanism of the main pump, is used for receiving the compensation pressure and the load pressure under the condition that the pilot pressure is input by the pilot pressure input part, and inputs the larger one of the compensation pressure and the load pressure into the main pump so as to control the displacement of the main pump.
Description
Technical Field
The invention relates to the technical field of hydraulic pressure, in particular to a hydraulic system with a flow compensation function and an engineering machine with the same.
Background
Load sensing control is a common control method for controlling the displacement of a main pump in modern construction machinery. The load sensing control is to control the discharge capacity of the main pump by detecting the pressure difference between the front and the rear of the main control valve, and maintain the constant pressure difference between the front and the rear of the main control valve, so as to realize the discharge flow of the main pump according to the system requirements. In a load sensing control system, a displacement adjustment mechanism of a main pump, such as a variable mechanism of a swash plate of the main pump, receives a signal from a load to adjust the displacement of the main pump in real time. However, under some working conditions, the load pressure is too low due to the fact that some actuating mechanisms are influenced by gravity, the swash plate variable mechanism of the main pump is controlled through the too low load pressure, and therefore the flow provided by the main pump is insufficient, and the actuating mechanisms are emptied.
Disclosure of Invention
The object of the present invention is to solve at least one of the above problems, and the object is achieved by the following technical solutions:
the invention provides a hydraulic system with flow compensation function, which is used for engineering machinery and comprises:
the main pump is connected with the oil tank and used for providing hydraulic oil for the hydraulic system in a load sensing control mode;
an actuator;
the main control valve is connected with the main pump and the executing mechanism and used for distributing hydraulic oil for the executing mechanism;
a pilot pressure input part coupled with the main control valve so as to be able to input a pilot pressure to the main control valve;
a flow compensation mechanism including a compensation pressure input part for inputting a constant compensation pressure to the flow compensation valve block, and a flow compensation valve block respectively coupled to the pilot pressure input part, the compensation pressure input part, a load pressure output line of the main control valve, and a displacement adjustment mechanism of the main pump, for receiving the compensation pressure and the load pressure in a case where the pilot pressure is input by the pilot pressure input part, and inputting the greater of the compensation pressure and the load pressure to the main pump to control a displacement of the main pump.
According to one improvement of the invention, the flow compensation valve block comprises a compensation pressure input valve and a pressure selection valve, wherein a first inlet of the pressure selection valve is connected with an outlet of the compensation pressure input valve, a second inlet of the pressure selection valve is connected with a load pressure output pipeline of the main control valve, and an outlet of the pressure selection valve is connected with a displacement adjusting mechanism of the main pump; the compensation pressure input valve is coupled with the pilot pressure input part so as to be openable or closable by a pilot pressure, and an inlet of the compensation pressure input valve is coupled with the compensation pressure input part, and an outlet of the compensation pressure input valve is coupled with the pressure selection valve such that the compensation pressure input valve is openable by a pilot pressure so as to allow the constant compensation pressure input by the compensation pressure input part to be delivered to the pressure selection valve, which inputs the greater of the received compensation pressure and load pressure into a displacement adjustment mechanism of the main pump to control the displacement of the main pump.
Preferably, the compensation pressure input valve is a pilot operated directional control valve and the pressure selection valve is a shuttle valve.
Further preferably, the pilot operated directional control valve is a pilot operated two-position three-way valve.
According to another improvement of the invention, the flow compensation valve block comprises a compensation pressure input valve and a pressure selection valve, wherein a first inlet of the pressure selection valve is connected with an outlet of the compensation pressure input valve, a second inlet of the pressure selection valve is connected with a load pressure output pipeline of the main control valve, and an outlet of the pressure selection valve is connected with a displacement adjusting mechanism of the main pump; the inlet of the compensating pressure input valve is coupled with the compensating pressure input component, and the outlet of the compensating pressure input valve is coupled with the pressure selection valve; the hydraulic system further includes an electronic control unit, and the compensating pressure input valve and the pilot pressure input part are respectively coupled with the electronic control unit such that when the pilot pressure input part is operated, the electronic control unit controls the compensating pressure input valve to be opened so that the constant compensating pressure input by the compensating pressure input part is delivered to the pressure selection valve, and the pressure selection valve inputs the larger of the received compensating pressure and load pressure into the displacement adjustment mechanism of the main pump to control the displacement of the main pump.
Preferably, the compensation pressure input valve is a solenoid directional valve and the pressure selection valve is a shuttle valve.
Further preferably, the hydraulic control directional control valve is an electromagnetic two-position three-way valve.
According to an advantageous embodiment of the invention, the compensation pressure value is 35 bar.
According to a further development of the invention, the compensation pressure input means is a gear pump which operates synchronously with the main pump.
In addition, the invention also relates to a working machine which is equipped with the hydraulic system.
The invention has the advantages that: the hydraulic system with the flow compensation function can realize the automatic flow compensation function under the working condition of low load pressure of the hydraulic system by adding the flow compensation mechanism. The flow compensation mechanism is simple in structure, can automatically adjust the flow without additional operation, is convenient to use, can be favorably applied to a hydraulic system for load sensing control, and has wide market application prospect.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 shows a schematic diagram of a hydraulic system with flow compensation according to an embodiment of the invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
According to an embodiment of the present invention, there is provided a hydraulic system with a flow compensation function for a construction machine, as shown in fig. 1, the hydraulic system including: the hydraulic system comprises a main pump 1 connected with a fuel tank so as to provide hydraulic oil for the hydraulic system in a load sensing control mode, an actuating mechanism 3, a main control valve 2, a pilot pressure input component for inputting pilot pressure to the main control valve 2 and a flow compensation mechanism. The main control valve 2 is connected with the main pump 1 and the actuating mechanism 3, and is used for distributing hydraulic oil output by the main pump 1 to the actuating mechanism 3. The flow compensation mechanism includes a compensation pressure input member (not shown) and a flow compensation valve block 4. According to a preferred embodiment of the invention, the compensation pressure input means is a gear pump operating synchronously with the main pump, both the gear pump and the main pump being driven by the engine, the gear pump being capable of inputting a constant value of compensation pressure to the flow compensation valve block, the value of the compensation pressure being set to be sufficient to ensure that the flow provided by the main pump at this pressure avoids the actuator being emptied, according to a preferred embodiment of the invention, the value of the compensation pressure is set to 35bar, however it is to be understood that the value of the compensation pressure may be set to other values depending on the characteristics and the specific operating environment of the working machine and its actuator equipped with the hydraulic system of the invention. According to a preferred embodiment of the present invention, the flow compensation valve block 4 includes a pilot-controlled directional control valve 5 and a shuttle valve 6, the pilot-controlled directional control valve 5 as the compensation pressure input valve may be a pilot-controlled two-position three-way valve as shown in fig. 1, the pilot-controlled directional control valve 5 is coupled to a pilot pressure input part, such as a pilot handle, so that a directional function can be performed by a liquid pressure of the pilot pressure input part; the inlet of the pilot operated directional control valve 5 is coupled with the compensation pressure input part, one outlet of the pilot operated directional control valve 5 is coupled to the first inlet of the shuttle valve 6, and the other outlet can be connected back to the oil tank. Therefore, when the pilot pressure is input from the pilot pressure input means, the pilot-operated directional control valve 5 is opened by the hydraulic pressure, that is, the gear pump as the compensation pressure input means and the shuttle valve as the pressure selection valve are connected, so that the compensation pressure having a constant value input from the gear pump is supplied to the shuttle valve 6 via the pilot-operated directional control valve 5. The second inlet of the shuttle valve 6 is coupled to a load pressure input line from the main control valve 2 so that the greater of the compensation pressure and the load pressure can be automatically delivered to the main pump 1, for example, to a swash plate variable mechanism of the main pump 1, which is a displacement adjusting mechanism of the main pump 1, and thus the displacement of the main pump can be adjusted according to the input pressure based on a load sensing control principle to ensure that the actuator is not emptied at the displacement. In other words, when the pilot pressure input means inputs the pilot pressure, the pilot pressure both manipulates the main control valve 2 and opens the pilot-operated directional control valve 5 in the flow rate compensation valve block 4. Therefore, the flow compensation of the flow compensation mechanism can realize the automatic compensation function of the flow only by the pilot operation.
According to an alternative embodiment of the present invention, the hydraulic system with flow compensation function of the present invention further includes an electronic control unit, and the pilot operated directional valve in the flow compensation valve block is replaced with a solenoid directional valve as the compensation pressure input valve member, such as a solenoid two-position three-way valve. The solenoid directional valve and the pilot pressure input part are respectively coupled with an electronic control unit, when the pilot pressure input part, such as a pilot handle, is operated, the electronic control unit receives an operation signal of the pilot pressure input part to control the opening of the solenoid directional valve, so that a compensation pressure with a constant value input by the gear pump is input to the shuttle valve 6 through the opened solenoid directional valve, and the shuttle valve 6 automatically compares the received compensation pressure with a load pressure input by the main control valve 2 at the other side and inputs the larger of the received compensation pressure and the load pressure to the main pump 1 to control the displacement of the main pump.
Through the above operation, in the case where the compensation pressure is set to 35bar, which is constant as described above, the displacement of the main pump is controlled by the load pressure if the load pressure input to the shuttle valve is greater than 35bar, and the displacement of the main pump is controlled at 35bar if the load pressure input to the shuttle valve is less than or equal to 35bar, thereby ensuring the flow rate of the hydraulic system to prevent the actuator from being suctioned due to insufficient flow rate.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (9)
1. A hydraulic system with flow compensation, the hydraulic system being for a work machine, the hydraulic system comprising:
the main pump is connected with the oil tank and used for providing hydraulic oil for the hydraulic system in a load sensing control mode;
an actuator;
the main control valve is connected with the main pump and the executing mechanism and used for distributing hydraulic oil for the executing mechanism;
a pilot pressure input part coupled with the main control valve so as to be able to input a pilot pressure to the main control valve;
the flow compensation mechanism comprises a compensation pressure input part and a flow compensation valve block, the flow compensation valve block comprises a compensation pressure input valve and a pressure selection valve, a first inlet of the pressure selection valve is connected with an outlet of the compensation pressure input valve, a second inlet of the pressure selection valve is connected with a load pressure output pipeline of the main control valve, and an outlet of the pressure selection valve is connected with a displacement adjusting mechanism of the main pump; the compensating pressure input valve is coupled with the pilot pressure input part so as to be opened or closed by a pilot pressure, and an inlet of the compensating pressure input valve is coupled with the compensating pressure input part, and an outlet of the compensating pressure input valve is coupled with the pressure selecting valve so that the compensating pressure input valve is opened by the pilot pressure so that a constant compensating pressure input by the compensating pressure input part is delivered to the pressure selecting valve, which inputs the greater of the received compensating pressure and a load pressure into a displacement adjusting mechanism of the main pump to control a displacement of the main pump.
2. The hydraulic system of claim 1, wherein the compensation pressure input valve is a pilot operated directional control valve and the pressure selection valve is a shuttle valve.
3. The hydraulic system of claim 2, wherein the pilot operated directional control valve is a pilot operated two position three way valve.
4. The hydraulic system of claim 1, further comprising an electronic control unit, the compensation pressure input valve and the pilot pressure input component being respectively coupled with the electronic control unit such that when the pilot pressure input component is operated, the electronic control unit controls the compensation pressure input valve to be opened such that the constant compensation pressure input by the compensation pressure input component is delivered to the pressure selection valve, the pressure selection valve inputting the greater of the received compensation pressure and load pressure into a displacement adjustment mechanism of the main pump to control a displacement of the main pump.
5. The hydraulic system of claim 4, wherein the compensation pressure input valve is a solenoid directional valve and the pressure selection valve is a shuttle valve.
6. The hydraulic system of claim 5, wherein the solenoid directional valve is a solenoid two-position, three-way valve.
7. The hydraulic system of claim 1, wherein the offset pressure value is 35 bar.
8. The hydraulic system of any one of claims 1 to 7, wherein the compensating pressure input member is a gear pump operating in synchronization with the main pump.
9. A working machine, characterized in that the working machine is equipped with a hydraulic system according to any one of claims 1-8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710690871.4A CN107477039B (en) | 2017-08-14 | 2017-08-14 | Hydraulic system with flow compensation function and engineering machinery |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710690871.4A CN107477039B (en) | 2017-08-14 | 2017-08-14 | Hydraulic system with flow compensation function and engineering machinery |
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| Publication Number | Publication Date |
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| CN107477039A CN107477039A (en) | 2017-12-15 |
| CN107477039B true CN107477039B (en) | 2020-01-03 |
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| CN201710690871.4A Active CN107477039B (en) | 2017-08-14 | 2017-08-14 | Hydraulic system with flow compensation function and engineering machinery |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103097743A (en) * | 2010-09-09 | 2013-05-08 | 沃尔沃建造设备有限公司 | Flow rate control device for variable displacement type hydraulic pump for construction equipment |
| CN106224306A (en) * | 2016-09-29 | 2016-12-14 | 徐工集团工程机械股份有限公司科技分公司 | There is the hydraulic system of flow-compensated function |
| CN106438527A (en) * | 2016-11-16 | 2017-02-22 | 中航力源液压股份有限公司 | Flow compensation method and flow compensation device for proportional control pump |
| CN106715801A (en) * | 2014-09-19 | 2017-05-24 | 沃尔沃建造设备有限公司 | Hydraulic circuit for construction equipment |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6292979B2 (en) * | 2014-05-26 | 2018-03-14 | Ｋｙｂ株式会社 | Load sensing control circuit |
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2017
- 2017-08-14 CN CN201710690871.4A patent/CN107477039B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103097743A (en) * | 2010-09-09 | 2013-05-08 | 沃尔沃建造设备有限公司 | Flow rate control device for variable displacement type hydraulic pump for construction equipment |
| CN106715801A (en) * | 2014-09-19 | 2017-05-24 | 沃尔沃建造设备有限公司 | Hydraulic circuit for construction equipment |
| CN106224306A (en) * | 2016-09-29 | 2016-12-14 | 徐工集团工程机械股份有限公司科技分公司 | There is the hydraulic system of flow-compensated function |
| CN106438527A (en) * | 2016-11-16 | 2017-02-22 | 中航力源液压股份有限公司 | Flow compensation method and flow compensation device for proportional control pump |
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| CN107477039A (en) | 2017-12-15 |
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Address after: 261061 Shandong city in Weifang province Fu hi tech Industrial Development Zone, East Street No. 197 Patentee after: WEICHAI POWER Co.,Ltd. Patentee after: Weichai Hydraulic Transmission Co.,Ltd. Address before: 261061 Shandong city in Weifang province Fu hi tech Industrial Development Zone, East Street No. 197 Patentee before: WEICHAI POWER Co.,Ltd. Patentee before: LINDE HYDRAULICS (CHINA) Co.,Ltd. |