CN216951076U - External control adjustable overflow valve group, hydraulic system and engineering machinery - Google Patents
External control adjustable overflow valve group, hydraulic system and engineering machinery Download PDFInfo
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- CN216951076U CN216951076U CN202220142125.8U CN202220142125U CN216951076U CN 216951076 U CN216951076 U CN 216951076U CN 202220142125 U CN202220142125 U CN 202220142125U CN 216951076 U CN216951076 U CN 216951076U
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Abstract
The utility model relates to a hydraulic component, and aims to solve the problems that a pressure regulating overflow valve in a hydraulic system of the existing engineering machinery is inconvenient to regulate pressure and has safety risk. Compared with the prior art, the utility model controls the overflow opening pressure of high-pressure oil through low-pressure oil, reduces the requirements of corresponding hydraulic devices, prolongs the service life of the devices, and improves the safety and convenience of pressure regulating operation.
Description
Technical Field
The utility model relates to a hydraulic component, in particular to an externally-controlled adjustable overflow valve group, a hydraulic system and engineering machinery.
Background
The working machine mostly uses hydraulic oil in a hydraulic system as an energy transmission medium. In the hydraulic system, a hydraulic pump sucks hydraulic oil from a hydraulic oil tank, outputs the hydraulic oil through a pipeline, controls the direction and the flow rate to flow to a hydraulic execution part through a control valve, and drives the hydraulic execution part to act.
With the continuous development of engineering machinery, more and more varieties of accessories are developed, different accessories correspond to different system maximum pressure requirements, and even the system maximum pressure required by the same accessory due to different acting objects is different.
In order to meet the highest pressure requirements of various systems with different accessories, a pressure regulating overflow valve for regulating the pressure of a hydraulic system is generally integrated in a main control valve. The regulation of pressure regulating overflow valve is manual regulation usually, but because the pressure regulating overflow valve is generally integrated in the main control valve assembly, general space is narrow, the regulation is difficult, and need suppress pressure operation to actuating mechanism simultaneously when adjusting overflow valve pressure, system pressure is very high this moment, there is the motion probably because of suppressing pressure operator's factors such as maloperation, or there is the pipeline oil leak to lead to risks such as high-pressure hydraulic oil injection, there is very big potential safety hazard to pressure regulator this moment, so to the frequent local more and more scheme that adopts the electric proportional overflow valve that needs carry out pressure regulation, avoid artifical direct regulation overflow valve, avoid the potential safety hazard.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problems that the pressure regulation of a pressure regulating overflow valve in the hydraulic system of the existing engineering machinery is inconvenient and has safety risk, and provides an external control adjustable overflow valve group, a hydraulic system and the engineering machinery, which are used for conveniently and safely regulating the system pressure of the hydraulic system.
The technical scheme for realizing the purpose of the utility model is as follows: an external control adjustable overflow valve set is constructed and used for an engineering machinery hydraulic system, and is characterized by comprising an electric proportional pressure reducing valve and a two-way valve, wherein the two-way valve comprises a valve core and is provided with a P cavity, a T port and a C cavity which are communicated with an oil inlet, a valve port between the T port and the P cavity is axially moved and communicated or closed by the valve core, the acting surface points of the C cavity and the P cavity in the axial direction of the valve core are Sc and Sp respectively, the acting force directions of oil in the two cavities on the valve core are opposite, the ratio of Sc to Sp is greater than 3, preferably greater than 5, and the oil outlet of the electric proportional pressure reducing valve is connected with the C cavity of the two-way valve.
In the utility model, the T port of the two-way valve is used for communicating the oil tank, when the two-way valve is communicated, the pressure of the P port is reduced, and the reduction amplitude is increased along with the increase of the opening degree of the valve port of the two-way valve. Because the ratio of the highest pressure of the P cavity to the pressure of the C cavity is equal to the ratio of Sc to Sp, the control of the higher pressure (working pressure of the engineering machinery) of the P cavity can be realized by inputting smaller pressure, such as the pressure of a pilot pressure oil source, into the C cavity. According to the utility model, the external control adjustable overflow valve group is used for controlling the opening and closing of the two-way valve, the control pressure is not from an oil path connected with an oil inlet of the two-way valve, the pressure of an oil source for controlling is irrelevant to the pressure of the oil inlet of the two-way valve, and a low-pressure oil source is used by utilizing the area difference; compared with the high-pressure overflow control by using high pressure, the requirement of a hydraulic device is greatly reduced, the service life of the device is greatly prolonged, the highest pressure of the P cavity of the two-way valve can be safely, reliably and conveniently regulated by using the electric proportional pressure reducing valve, and when the externally-controlled adjustable overflow valve group is applied to a hydraulic system, the highest pressure regulation of a hydraulic actuating element in the hydraulic system can be realized.
When the ratio of Sc to Sp in the two-way valve is larger than 5, a pilot pressure oil source can be used as a pressure oil source for being connected with the electric proportional pressure reducing valve for control, and the controllable maximum pressure is larger than 20 MPa when the ratio of Sc to Sp is larger than 5 according to the setting of pilot pressure on most engineering machinery, so that the pressure regulation requirements of most accessories can be met.
In the externally-controlled adjustable overflow valve bank, the electric proportional pressure reducing valve is an inverse proportional electric proportional pressure reducing valve. When the electric proportional pressure reducing valve is an inverse proportional electric proportional pressure reducing valve, the smaller the control current of the electric proportional pressure reducing valve is, the larger the pressure of an oil outlet of the electric proportional pressure reducing valve is, and when the control current is zero, the pressure of the oil outlet reaches the maximum.
The electric proportional pressure reducing valve can also be a proportional electric proportional pressure reducing valve, namely, the larger the control current of the electric proportional pressure reducing valve is, the larger the pressure of the oil outlet is, when the electric proportional valve is powered off, the pressure of the oil outlet is zero, and the overflow pressure of the two-way valve is also reduced to the lowest. For some working conditions, when a fault occurs, such as the power failure of the electric proportional pressure reducing valve, the corresponding hydraulic actuating part is required to stop working to ensure safety, and the working conditions need that the electric proportional pressure reducing valve is a proportional electric proportional pressure reducing valve.
In the external control adjustable overflow valve group, a control valve is arranged on a connecting oil path between an oil outlet of the electric proportional pressure reducing valve and the cavity C, when the pressure of an oil inlet of the electric proportional pressure reducing valve is smaller than a preset value, the control valve closes an oil path between the electric proportional pressure reducing valve and the cavity C, otherwise, the control valve conducts the oil path between the electric proportional pressure reducing valve and the cavity C. If the oil path connected with the oil inlet of the electric proportional pressure reducing valve fails to provide an oil source with preset pressure, for example, a pump providing the pressure oil source stops working suddenly, the oil outlet of the electric proportional pressure reducing valve cannot output corresponding pressure, the opening pressure of the two-way valve is reduced, and a corresponding hydraulic actuator can generate safety risk. After the control valve is arranged, when the pressure of an oil inlet of the electric proportional pressure reducing valve is smaller than a preset value, the control valve is stopped, so that oil in a cavity C of the two-way valve cannot flow out through the electric proportional pressure reducing valve, and the two-way valve cannot be opened at a full valve port due to sudden pressure loss of the control pressure.
In the external control adjustable overflow valve group, the control valve is a two-position three-way valve, a first oil port of the control valve is connected with an oil outlet of the electric proportional pressure reducing valve, a second oil port of the control valve is connected with the cavity C, a third oil port of the control valve is connected with an oil inlet of the two-way valve, and one of the second oil ports is communicated with the first oil port or the third oil port. When the pressure of an oil inlet of the electric proportional pressure reducing valve is smaller than a preset value, the control valve is reversed, high-pressure oil of the oil inlet of the two-way valve is led into the cavity C, and the two-way valve is ensured to be in a closed state. Furthermore, the control valve is an electromagnetic valve and is controlled by a controller, and the controller acquires related parameters to perform logic judgment to control the working position of the control valve. The control valve can also be a hydraulic control valve, the hydraulic control end of the control valve is connected with the oil inlet of the electric proportional pressure reducing valve, and when the oil inlet of the electric proportional pressure reducing valve is lower than a set value, the control valve is reversed under the action of the elastic force of an inner spring of the control valve.
The technical scheme for realizing the purpose of the utility model is as follows: the hydraulic system is constructed and comprises a main control valve, a hydraulic actuating part, a pilot oil source and a hydraulic oil tank, wherein the hydraulic actuating part, the pilot oil source and the hydraulic oil tank are connected with the main control valve through pipelines. In a hydraulic system, the pressure output by a pilot oil source such as a pilot pump or a pilot oil supply valve is about 4 MPa, the maximum pressure output by an electric proportional pressure reducing valve is about 3 MPa generally, and if the ratio of Sc to Sp is 10, the overflow control of the oil inlet of the two-way valve below the maximum pressure of 30 MPa can be realized.
The technical scheme for realizing the purpose of the utility model is as follows: a working machine is constructed, which is characterized by the aforementioned hydraulic system, and which may be a loader, an excavator or the like.
Compared with the prior art, the utility model realizes that the low-pressure oil is used for controlling the overflow starting pressure of the high-pressure oil through the combination of the electric proportional pressure reducing valve and the two-way valve, reduces the requirements of corresponding hydraulic devices, prolongs the service life of the devices, and improves the safety and the convenience of pressure regulating operation.
Drawings
Fig. 1 is a schematic diagram of a first embodiment of an externally controlled adjustable overflow valve group of the present invention.
Fig. 2 is a schematic diagram of the hydraulic system of the present invention.
Fig. 3 is a schematic diagram of a second embodiment of the externally controlled adjustable spill valve assembly of the present invention.
Fig. 4 is a schematic diagram of a third embodiment of the externally controlled adjustable spill valve assembly of the present invention.
Part names and serial numbers in the figure:
the hydraulic control system comprises an electric proportional pressure reducing valve 1, a two-way valve 2, a valve core 21, a C cavity 22, a P cavity 23, a control valve 3, an external control adjustable overflow valve group 40, a hydraulic oil tank 41, a working pump 42, a pilot pump 43, a main control valve 44, a first hydraulic actuator 45, a second hydraulic actuator 46, a third hydraulic actuator 47 and a pilot valve 48.
Detailed Description
The following description of the embodiments refers to the accompanying drawings.
As shown in fig. 1, the external control adjustable overflow valve set in the present embodiment is composed of an electric proportional pressure reducing valve 1 and a two-way valve 2. The two-way valve 2 is a cartridge valve and is provided with an oil inlet P, T port, a P cavity 23, a C cavity 22, a valve core 21 and the like, the P cavity is connected with the oil inlet P, a valve port between the T port and the P cavity is axially moved and communicated or closed by the valve core 21, the acting surface areas of the C cavity 22 and the P cavity 23 in the axial direction of the valve core 21 are respectively Sc and Sp, the direction of the acting force of the oil liquid in the C cavity 22 on the valve core of the two-way valve is opposite to the direction of the acting force of the oil liquid in the P cavity on the valve core of the two-way valve, and the ratio of Sc to Sp is larger than 3, preferably larger than 5. An oil outlet of the electric proportional pressure reducing valve 1 is connected with a cavity C of the two-way valve 2.
The externally-controlled adjustable overflow valve bank is used in hydraulic systems of engineering machinery such as loaders and excavators, is practical as an overflow valve and is used for adjusting the highest working pressure of a hydraulic actuating piece.
Fig. 2 shows a part of a hydraulic system of an excavator, which comprises a hydraulic oil tank 41, a working pump 42, a pilot pump 43, a main control valve 44, a first hydraulic actuator 45, a second hydraulic actuator 46, a third hydraulic actuator 47, a pilot valve 48 and the above-mentioned external control adjustable overflow valve group 40.
The working pump 42 and the pilot pump 43 are connected to the hydraulic oil tank 41 through a pipeline, and the hydraulic oil is sucked from the hydraulic oil tank 41 and output. A pump port of the working pump 42 is connected to the main control valve 44 through a pipe, and a pump port of the pilot pump 43 is connected to the pilot valve 47.
The main control valve 44 has triple main valves, and the first, second, and third hydraulic actuators 45, 46, and 47 are connected to the corresponding main valves, respectively. The pilot valves 48 are connected to pilot control ends of main valves in the main control valve 44, and the control of the corresponding pilot valves 48 can control hydraulic actuators such as the first hydraulic actuator 45, the second hydraulic actuator 46, and the third hydraulic actuator 47 through the corresponding main valve.
In the external control adjustable overflow valve group, an oil inlet Pi of the electric proportional pressure reducing valve is connected with a pump port of a pilot pump 43, an oil inlet P of the two-way valve is connected on an oil path between a third hydraulic actuating part 47 and a working oil port of a third main valve, and a port T of the two-way valve 2 is connected with a hydraulic oil tank 41.
In the present embodiment, the pilot pump 43 is used as a pilot oil source, and the maximum pilot pressure output from the pump port thereof is limited by a relief valve inside thereof, and the pressure is usually 4 mpa. By providing a relief valve in the main control valve 44, the highest pressure in the hydraulic system can be defined, which pressure normally meets the hydraulic pressure requirements of most hydraulic actuators.
In a construction machine, the first hydraulic actuator 45 and the second hydraulic actuator 46 are usually fixed, and in a loader, for example, the first hydraulic actuator 45 and the second hydraulic actuator 46 usually correspond to a boom cylinder and a swing cylinder. The third hydraulic actuator 47 is typically a hydraulic attachment that is selectively installed according to work requirements. The opening pressure of the relief valve in the main control valve is usually set in accordance with the working pressures of the first hydraulic actuator and the second hydraulic actuator. The working pressure of the third hydraulic actuator is not always determined, but is lower than the opening pressure of the relief valve in the main control valve. In order to meet the pressure requirement of the third hydraulic actuator, the maximum pressure is limited by the external control adjustable overflow valve group.
The pressure input by the oil inlet of the electric proportional pressure reducing valve 1 is 4 MPa of the pressure of the pump opening of the pilot pump, and the maximum pressure of the oil outlet of the electric proportional pressure reducing valve is usually 3 MPa. The electric proportional pressure reducing valve 1 is a proportional electric proportional pressure reducing valve, the pressure of an oil outlet of the electric proportional pressure reducing valve is in positive correlation with the control current of the electric proportional pressure reducing valve, namely the larger the control current is, the higher the pressure of the oil outlet is, when the electric proportional pressure reducing valve is powered off, the oil outlet is communicated with the hydraulic oil tank 41 through the electric proportional pressure reducing valve 1, and the pressure of the oil outlet is zero.
In the two-way valve, when the ratio of Sc to Sp is equal to 10 and the oil outlet of the electric proportional pressure reducing valve outputs the maximum pressure of 3 MPa, the pressure of a P cavity of the two-way valve 2 is required to be greater than 30 MPa to force a valve core of the two-way valve to move, so that the P cavity of the two-way valve is communicated with a T port, pressure oil of an oil inlet flows into a hydraulic oil tank through the two-way valve to cause overflow, the pressure of the oil inlet of the two-way valve is reduced, and the working pressure of a third hydraulic actuator is ensured not to exceed 30 MPa. By controlling the magnitude of the control current of the electric proportional pressure reducing valve 1, the oil outlet of the electric proportional pressure reducing valve 1 can be controlled between 0 and 3 MPa, and therefore the pressure of the oil inlet of the two-way valve is controlled between 0 and 30 MPa. And according to the requirement, the ratio of Sc to Sp is determined by design, so that the required voltage regulation range can be obtained.
In this embodiment, the overflow opening pressure of the two-way valve to the high-pressure oil (working pressure oil) is controlled by adjusting the low-pressure oil (pilot pressure oil) by using the electric proportional pressure reducing valve, so as to limit the highest working pressure. When the pressure of the oil inlet of the two-way valve is P and the pressure of the cavity C is Pc, when P is larger than Sc Pc/Sp, the two-way valve is opened, oil liquid at the oil inlet overflows, the pressure is reduced, and therefore the purpose of limiting the maximum pressure of an oil path connected with the oil inlet of the two-way valve is achieved.
In this embodiment, when the electric proportional pressure reducing valve is powered off, the pressure of the oil outlet is zero (or close to zero), the opening pressure of the two-way valve is also close to zero, and the third hydraulic actuator loses the supply of the high-pressure hydraulic oil and stops working. The proportional electro-proportional pressure reducing valve is suitable for certain working conditions, and when a circuit for controlling the electro-proportional pressure reducing valve is powered off accidentally, the third hydraulic actuating part is required to stop working immediately, so that safety is ensured.
Under some working conditions, in order to ensure safety, when a circuit for controlling the electro-proportional pressure reducing valve is unexpectedly powered off, the two-way valve cannot be opened, and the third hydraulic execution part needs to maintain the supply of high-pressure oil, for example, the third hydraulic execution part is a hydraulic oil cylinder for lifting a heavy object, at this time, the electro-proportional pressure reducing valve can be designed as an inverse-proportional electro-proportional pressure reducing valve, as shown in fig. 3, the pressure of an oil outlet of the electro-proportional pressure reducing valve is inversely related to the control current of the electro-proportional pressure reducing valve, namely, the higher the control current is, the lower the pressure of the oil outlet is, when the electro-proportional pressure reducing valve is powered off, the pressure of the oil outlet reaches the highest, at this time, if the circuit for controlling the electro-proportional pressure reducing valve is unexpectedly powered off, the two-way valve cannot be opened, and the third hydraulic execution part cannot cause uncontrollable action due to loss.
In the externally controlled adjustable overflow valve set in fig. 1 and 3, if the oil inlet of the electro-proportional pressure reducing valve loses the pilot pressure oil supply, for example, the pilot oil source (the pilot pump or the pilot oil supply valve fails), the oil outlet pressure of the electro-proportional pressure reducing valve 1 will drop to zero, the two-way valve is opened, the third hydraulic actuator will lose the pressure oil supply, and the third hydraulic actuator will stop working or uncontrollable action will occur. In order to avoid the situation, a control valve is arranged on a connecting oil path between an oil outlet of the electric proportional pressure reducing valve and the cavity C, when the pressure of an oil inlet of the electric proportional pressure reducing valve is smaller than a preset value, the control valve closes an oil path between the electric proportional pressure reducing valve and the cavity C, otherwise, the control valve conducts the oil path between the electric proportional pressure reducing valve and the cavity C. The control valve can be an electromagnetic valve and is controlled by a complete machine controller of the engineering machinery, and the complete machine controller acquires relevant parameters to control the working position of the control valve after logic judgment. The control valve can also be a hydraulic control valve, the hydraulic control end of the control valve is connected with the oil inlet of the electric proportional pressure reducing valve, and when the oil inlet of the electric proportional pressure reducing valve is lower than a set value, the control valve is reversed under the action of the elastic force of an inner spring of the control valve to close the control valve.
The control valve can be a two-position two-way valve or a two-position three-way valve. If the control valve is a two-position two-way valve, the control valve closes an oil way between the electric proportional pressure reducing valve and the cavity C when the pressure of an oil inlet of the electric proportional pressure reducing valve is smaller than a preset value, and conducts the oil way between the electric proportional pressure reducing valve and the cavity C when the pressure of the oil inlet is larger than the preset value. If the control valve is a two-position three-way valve, as shown in fig. 4, the first oil port is connected to the oil outlet of the electro-proportional pressure reducing valve, the second oil port is connected to the C cavity, the third oil port is connected to the oil inlet of the two-way valve, and one of the second oil ports is connected to the first oil port or the third oil port. When the pressure of an oil inlet of the electric proportional pressure reducing valve is smaller than a preset value, the second oil port is communicated with the third oil port, high-pressure oil of the oil inlet of the two-way valve is led into the cavity C, and the two-way valve is ensured to be in a closed state; when the pressure of an oil inlet of the electric proportional pressure reducing valve is larger than a preset value, the second oil port is communicated with the first oil port, and the two-way valve is controlled to be opened and closed by the pressure of an oil outlet of the electric proportional pressure reducing valve.
Claims (8)
1. The utility model provides an outer adjustable overflow valves of accuse for engineering machine tool hydraulic system, its characterized in that includes electric proportional pressure reducing valve and two-way valve, the two-way valve includes the case and is equipped with communicating P chamber with the oil inlet, T mouth and C chamber, the valve port between T mouth and the P chamber is moved by the case axial and is linked up or close, C chamber and P chamber are respectively Sc and Sp and the direction of the interior fluid of two chambeies is opposite on the case, the ratio of Sc and Sp is greater than 3, the oil-out of electric proportional pressure reducing valve is connected with the C chamber of two-way valve.
2. The externally controlled adjustable overflow valve set as claimed in claim 1, wherein the ratio of Sc to Sp in said two-way valve is greater than 5.
3. The externally controlled adjustable spill valve block of claim 1 or 2, wherein the electro proportional pressure reducing valve is an inverse proportional electro proportional pressure reducing valve.
4. The externally controlled adjustable overflow valve set according to claim 3, wherein a control valve is disposed on a connection oil path between the oil outlet of the electro proportional pressure reducing valve and the cavity C, and when the pressure of the oil inlet of the electro proportional pressure reducing valve is smaller than a predetermined value, the control valve closes the oil path between the electro proportional pressure reducing valve and the cavity C, and otherwise, the control valve conducts the oil path between the electro proportional pressure reducing valve and the cavity C.
5. The externally controlled adjustable overflow valve set according to claim 4, wherein the control valve is a two-position three-way valve, a first oil port of the control valve is connected to an oil outlet of the electro-proportional pressure reducing valve, a second oil port of the control valve is connected to the C cavity, a third oil port of the control valve is connected to an oil inlet of the two-way valve, and one of the second oil port and the first oil port or the third oil port is connected.
6. The externally controlled adjustable overflow valve set according to claim 4 or 5, wherein the control valve is an electromagnetic valve or a pilot operated valve, and a pilot operated end of the pilot operated valve is connected to an oil inlet of the electro proportional pressure reducing valve.
7. A hydraulic system comprises a main control valve, a hydraulic actuating part, a pilot oil source and a hydraulic oil tank, wherein the hydraulic actuating part, the pilot oil source and the hydraulic oil tank are connected with the main control valve through pipelines, the hydraulic system is characterized by further comprising an external control adjustable overflow valve group as claimed in any one of claims 1 to 6, an oil inlet of an electric proportional pressure reducing valve is connected with the pilot oil source, an oil inlet of a two-way valve is connected with an oil path between the hydraulic actuating part and the main control valve, and a T port of the two-way valve is connected with the hydraulic oil tank.
8. A working machine characterized by a hydraulic system as claimed in claim 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220142125.8U CN216951076U (en) | 2022-01-19 | 2022-01-19 | External control adjustable overflow valve group, hydraulic system and engineering machinery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220142125.8U CN216951076U (en) | 2022-01-19 | 2022-01-19 | External control adjustable overflow valve group, hydraulic system and engineering machinery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216951076U true CN216951076U (en) | 2022-07-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202220142125.8U Active CN216951076U (en) | 2022-01-19 | 2022-01-19 | External control adjustable overflow valve group, hydraulic system and engineering machinery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216951076U (en) |
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2022
- 2022-01-19 CN CN202220142125.8U patent/CN216951076U/en active Active
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