阅读说明：本技术 气压平衡控制装置的控制方法、控制系统和工程机械 (Control method and control system of air pressure balance control device and engineering machinery ) 是由 李文举 张磊 游仕平 杨正维 宫永辉 于 2021-08-16 设计创作，主要内容包括：本发明实施例提供一种气压平衡控制装置的控制方法、一种气压平衡控制装置的控制系统和一种工程机械,属于工程机械领域。所述气压平衡控制装置用于液压油箱的气压平衡,所述气压平衡控制装置包括液压系统和呼吸阀,所述液压油箱用于为所述液压系统提供液压液体,所述呼吸阀用于平衡所述液压油箱内的气体压力；所述控制方法包括：检测液压油箱的工作状态参数；根据液压油箱的工作状态参数确定呼吸阀的控制参数；根据呼吸阀的控制参数控制呼吸阀动作以平衡液压油箱内的气体压力。本发明将液压油箱的工作状态参数作为呼吸阀的控制参数,可以更好地使得油箱内的气体压力达到平衡。(The embodiment of the invention provides a control method of an air pressure balance control device, a control system of the air pressure balance control device and engineering machinery, and belongs to the field of engineering machinery. The air pressure balance control device is used for air pressure balance of a hydraulic oil tank and comprises a hydraulic system and a breather valve, the hydraulic oil tank is used for providing hydraulic liquid for the hydraulic system, and the breather valve is used for balancing gas pressure in the hydraulic oil tank; the control method comprises the following steps: detecting working state parameters of a hydraulic oil tank; determining control parameters of the breathing valve according to the working state parameters of the hydraulic oil tank; and controlling the breathing valve to act according to the control parameter of the breathing valve so as to balance the gas pressure in the hydraulic oil tank. The invention uses the working state parameter of the hydraulic oil tank as the control parameter of the breathing valve, and can better balance the gas pressure in the oil tank.)

1. A control method of a pneumatic balance control device for pneumatic balance of a hydraulic oil tank (7), the pneumatic balance control device being characterized by comprising a hydraulic system and a breather valve (5), the hydraulic oil tank (7) being used for providing hydraulic fluid required for power transmission to the hydraulic system, and the breather valve (5) being used for balancing gas pressure in the hydraulic oil tank (7), the control method comprising:

detecting working state parameters of a hydraulic oil tank (7);

determining control parameters of the breather valve (5) according to working state parameters of the hydraulic oil tank (7);

and controlling the breathing valve (5) to act according to the control parameter of the breathing valve (5) so as to balance the gas pressure in the hydraulic oil tank (7).

2. A control method according to claim 1, characterized in that the operating state parameters of the hydraulic tank (7) comprise: the temperature parameters and the gas pressure parameters of the hydraulic liquid in the hydraulic oil tank (7);

the step of detecting the working state parameters of the hydraulic oil tank (7) comprises the following steps: detecting a temperature parameter and a gas pressure parameter of hydraulic liquid of a hydraulic oil tank;

the step of determining the control parameters of the breather valve (5) according to the working state parameters of the hydraulic oil tank (7) comprises the following steps: and determining the control parameters of the breather valve (5) according to the temperature parameters and the gas pressure parameters of the hydraulic liquid in the hydraulic oil tank (7).

3. A control method according to claim 1, characterized in that the operating state parameters of the hydraulic tank (7) comprise: -a gas pressure parameter in the hydraulic tank (7), -a step of detecting a working condition parameter of the hydraulic tank (7), comprising: detecting a gas pressure parameter in the hydraulic oil tank (7);

the step of determining the control parameters of the breather valve (5) according to the working state parameters of the hydraulic oil tank (7) comprises the following steps: and determining the control parameters of the breather valve (5) according to the gas pressure parameters in the hydraulic oil tank (7).

4. A control method according to claim 2 or 3, characterized in that the step of detecting a gas pressure parameter of the hydraulic oil tank (7) comprises: and detecting gas pressure parameters in the hydraulic oil tank according to the hydraulic stroke of the hydraulic cylinder of the hydraulic system.

5. The control method according to claim 1, characterized in that before the step of controlling the action of the breather valve (5) to balance the gas pressure in the hydraulic oil tank (7) according to the control parameter of the breather valve (5), it further comprises:

acquiring the working state of a driving mechanism in a hydraulic system, and determining the driving state of the hydraulic system according to the working state of the driving mechanism;

and determining the control parameters of the breather valve (5) according to the working state parameters of the hydraulic oil tank (7) and the driving state of the hydraulic system.

6. Control method according to claim 5, characterized in that the operating state parameters of the hydraulic tank (7) comprise: the temperature parameters and the gas pressure parameters of the hydraulic liquid in the hydraulic oil tank (7);

the control parameters of the breather valve (5) are determined according to the working state parameters of the hydraulic oil tank (7) and the driving state of the hydraulic system, and the control parameters comprise:

if the driving state of the hydraulic system is the driving state of the hydraulic cylinder and the temperature parameter of the hydraulic liquid in the hydraulic oil tank (7) is kept constant in a preset time period, determining the control parameter of the breather valve (5) according to the gas pressure parameter in the hydraulic oil tank (7);

and if the driving state of the hydraulic system is the driving state of the hydraulic motor, and the gas pressure parameter in the hydraulic oil tank (7) is kept constant in a preset time period, determining the control parameter of the breather valve (5) according to the hydraulic liquid temperature parameter in the hydraulic oil tank (7).

7. A control system of a pneumatic balance control device, wherein the pneumatic balance control device is used for pneumatic balance of a hydraulic oil tank (7), the pneumatic balance control device comprises a hydraulic system and a breather valve (5), the hydraulic oil tank (7) is used for providing hydraulic liquid for the hydraulic system, the breather valve (5) is used for balancing gas pressure in the hydraulic oil tank (7), and the control system comprises:

the detection device is used for acquiring working state parameters of the hydraulic oil tank (7);

the controller is used for determining the control parameters of the breather valve (5) according to the working state parameters of the hydraulic oil tank (7); and controlling the breathing valve (5) to act according to the control parameter of the breathing valve (5) so as to balance the gas pressure in the hydraulic oil tank (7).

8. The control system according to claim 7, characterized in that the breather valve (5) comprises:

an electro-proportional valve having a first inlet port and a second inlet port;

and a filter;

wherein the filter is in communication with a first inlet of an electro proportional valve, a second inlet of which is in communication with the hydraulic tank (7);

the controller is specifically used for determining control parameters of the electro proportional valve according to working state parameters of the hydraulic oil tank (7); and controlling the electro proportional valve action according to the control parameter of the electro proportional valve so as to balance the gas pressure in the hydraulic oil tank (7).

9. The control system according to claim 7 or 8, characterized in that the detection means comprises: a detection unit and a temperature sensor;

the detection unit is used for detecting a gas pressure parameter in the hydraulic oil tank (7);

the temperature sensor is used for detecting the temperature parameter of the hydraulic liquid in the hydraulic oil tank (7);

the controller is used for determining control parameters of the breather valve (5) according to temperature parameters of hydraulic liquid in the hydraulic oil tank (7) and air pressure parameters in the hydraulic oil tank (7).

10. Control system according to claim 9, characterized in that the detection unit detects the air pressure in the hydraulic tank (7) by means of a hydraulic stroke taken from the hydraulic cylinders of the hydraulic system.

11. The control system of claim 9, wherein the hydraulic system includes a drive mechanism;

the controller is also used for acquiring the working state of a driving mechanism in the hydraulic system and determining the driving state of the hydraulic system according to the working state of the driving mechanism;

and determining the control parameters of the breather valve (5) according to the working state parameters of the hydraulic oil tank (7) and the driving state of the hydraulic system.

12. Control system according to claim 11, characterized in that the operating state parameters of the hydraulic tank (7) comprise: the temperature parameters and the gas pressure parameters of the hydraulic liquid in the hydraulic oil tank (7);

the controller is specifically used for determining the control parameter of the breather valve (5) according to the gas pressure parameter in the hydraulic oil tank (7) when the driving state of the hydraulic system is the hydraulic cylinder driving state and the temperature parameter of the hydraulic liquid in the hydraulic oil tank (7) is kept constant within a preset time period;

when the driving state of the hydraulic system is the hydraulic motor driving state, and the gas pressure parameter in the hydraulic oil tank (7) is kept constant in a preset time period, the control parameter of the breather valve (5) is determined according to the hydraulic liquid temperature parameter in the hydraulic oil tank (7).

13. A working machine, characterized by comprising a control system of the air pressure balance control apparatus according to any one of claims 7 to 12.

Technical Field

The invention relates to the field of engineering machinery, in particular to a control method of an air pressure balance control device, a control system of the air pressure balance control device and engineering machinery.

Background

In a hydraulic system, a breather valve not only ensures that hydraulic oil in a hydraulic oil tank is isolated from atmosphere within a certain pressure range, but also can be communicated with the atmosphere when the pressure is lower than a set pressure range.

The breather valve has the function in two aspects of malleation and negative pressure, and the concrete expression is that when the container bore certain malleation, the breather valve will open the expired gas and release malleation, and when the container bore negative pressure, the breather valve will open the inspired gas and release the negative pressure, guarantees that pressure is in certain within range to this guarantees the safety of container.

The existing breather valve is opened and closed by using a fixed reference value, is insensitive to reaction and cannot accurately control the internal pressure of a hydraulic oil tank, so that the service lives of hydraulic parts and hydraulic oil are influenced.

Disclosure of Invention

The embodiment of the invention aims to provide a control method of an air pressure balance control device, a control system of the air pressure balance control device and engineering machinery, which are used for better solving the problem of air pressure balance in a hydraulic oil tank.

In order to achieve the above object, the present invention provides a control method of a pneumatic balance control device, the pneumatic balance control device is used for pneumatic balance of a hydraulic oil tank, the pneumatic balance control device comprises a hydraulic system and a breather valve, the hydraulic oil tank is used for providing hydraulic liquid required by power transmission for the hydraulic system, the breather valve is used for balancing gas pressure in the hydraulic oil tank, the control method comprises:

detecting working state parameters of a hydraulic oil tank;

determining control parameters of the breathing valve according to the working state parameters of the hydraulic oil tank;

and controlling the breathing valve to act according to the control parameter of the breathing valve so as to balance the gas pressure in the hydraulic oil tank.

Optionally, the working state parameters of the hydraulic oil tank include: a hydraulic fluid temperature parameter and a gas pressure parameter in the hydraulic oil tank;

the step of detecting the working state parameters of the hydraulic oil tank comprises the following steps: detecting a temperature parameter and a gas pressure parameter of hydraulic liquid of a hydraulic oil tank;

the step of determining the control parameter of the breathing valve according to the working state parameter of the hydraulic oil tank comprises the following steps: and determining the control parameters of the breathing valve according to the temperature parameters and the gas pressure parameters of the hydraulic liquid in the hydraulic oil tank.

Optionally, the working state parameters of the hydraulic oil tank include: the step of detecting the working state parameter of the hydraulic oil tank comprises the following steps: detecting a gas pressure parameter in the hydraulic oil tank;

the step of determining the control parameter of the breathing valve according to the working state parameter of the hydraulic oil tank comprises the following steps: and determining the control parameters of the breathing valve according to the gas pressure parameters in the hydraulic oil tank.

Optionally, the step of detecting a gas pressure parameter of the hydraulic oil tank includes: and detecting gas pressure parameters in the hydraulic oil tank according to the hydraulic stroke of the hydraulic cylinder of the hydraulic system.

Optionally, before the step of controlling the action of the breather valve according to the control parameter of the breather valve to balance the gas pressure in the hydraulic oil tank, the method further includes:

acquiring the working state of a driving mechanism in a hydraulic system, and determining the driving state of the hydraulic system according to the working state of the driving mechanism;

and determining the control parameters of the breathing valve according to the working state parameters of the hydraulic oil tank and the driving state of the hydraulic system.

Optionally, the working state parameters of the hydraulic oil tank include: a hydraulic fluid temperature parameter and a gas pressure parameter in the hydraulic oil tank;

the method for determining the control parameters of the breathing valve according to the working state parameters of the hydraulic oil tank and the driving state of the hydraulic system comprises the following steps:

if the driving state of the hydraulic system is the driving state of the hydraulic cylinder and the temperature parameter of the hydraulic liquid in the hydraulic oil tank is kept constant in a preset time period, determining the control parameter of the breathing valve according to the gas pressure parameter in the hydraulic oil tank;

and if the driving state of the hydraulic system is the driving state of the hydraulic motor and the gas pressure parameter in the hydraulic oil tank is kept constant in a preset time period, determining the control parameter of the breathing valve according to the temperature parameter of the hydraulic liquid in the hydraulic oil tank.

The invention also provides a control system of a pneumatic balance control device, wherein the pneumatic balance control device is used for pneumatic balance of a hydraulic oil tank, the pneumatic balance control device comprises a hydraulic system and a breather valve, the hydraulic oil tank is used for providing hydraulic liquid for the hydraulic system, and the breather valve is used for balancing gas pressure in the hydraulic oil tank, the control system comprises:

the detection device is used for acquiring working state parameters of the hydraulic oil tank;

the controller is used for determining the control parameters of the breathing valve according to the working state parameters of the hydraulic oil tank; and controlling the breathing valve to act according to the control parameter of the breathing valve so as to balance the gas pressure in the hydraulic oil tank.

Optionally, the breather valve comprises:

an electro-proportional valve having a first inlet port and a second inlet port;

and a filter;

wherein the filter is in communication with a first inlet port of an electro-proportional valve, a second inlet port of the electro-proportional valve being in communication with the hydraulic tank; therefore, the controller is specifically used for determining the control parameters of the electro proportional valve according to the working state parameters of the hydraulic oil tank; and controlling the electric proportional valve to act according to the control parameter of the electric proportional valve so as to balance the gas pressure in the hydraulic oil tank.

Optionally, the detection device includes: a detection unit and a temperature sensor;

the detection unit is used for detecting gas pressure parameters in the hydraulic oil tank;

the temperature sensor is used for detecting the temperature parameter of the hydraulic liquid in the hydraulic oil tank;

the controller is used for determining the control parameters of the breathing valve according to the temperature parameters of the hydraulic liquid in the hydraulic oil tank and the air pressure parameters in the hydraulic oil tank.

Optionally, the detection unit detects an air pressure parameter in the hydraulic oil tank by obtaining a hydraulic stroke of a hydraulic cylinder of the hydraulic system.

Optionally, the hydraulic system comprises a drive mechanism;

the controller is also used for acquiring the working state of a driving mechanism in the hydraulic system and determining the driving state of the hydraulic system according to the working state of the driving mechanism;

and determining the control parameters of the breathing valve according to the working state parameters of the hydraulic oil tank and the driving state of the hydraulic system.

Optionally, the working state parameters of the hydraulic oil tank include: a hydraulic fluid temperature parameter and a gas pressure parameter in the hydraulic oil tank;

the controller is specifically used for determining the control parameter of the breathing valve according to the gas pressure parameter in the hydraulic oil tank when the driving state of the hydraulic system is the hydraulic cylinder driving state and the temperature parameter of the hydraulic liquid in the hydraulic oil tank is kept constant within a preset time period;

when the driving state of the hydraulic system is the driving state of the hydraulic motor and the gas pressure parameter in the hydraulic oil tank is kept constant in a preset time period, the control parameter of the breathing valve is determined according to the temperature parameter of the hydraulic liquid in the hydraulic oil tank.

The invention also provides engineering machinery which comprises a control system of the air pressure balance control device.

Through the technical scheme, the working state parameters of the hydraulic oil tank are used as the control parameters of the breathing valve, so that the gas pressure in the oil tank can be better balanced.

Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention without limiting the embodiments of the invention. In the drawings:

fig. 1 is a schematic structural diagram of an air pressure balance control device according to an embodiment of the present invention;

fig. 2 is a schematic flow chart illustrating a control method of an air pressure balance control device according to an embodiment of the present invention;

fig. 3 is a schematic flow chart of a control method of another air pressure balance control device according to an embodiment of the present invention;

fig. 4 is a schematic flow chart illustrating a control method of another air pressure balance control device according to an embodiment of the present invention;

fig. 5 is a flowchart illustrating a control method of another air pressure balance control device according to an embodiment of the present invention.

Description of the reference numerals

A hydraulic pump 1; a main valve 2; a stroke sensor 3; a hydraulic cylinder 4;

a breather valve 5; an air pressure sensor 6; a hydraulic oil tank 7; a temperature sensor 8.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating embodiments of the invention, are given by way of illustration and explanation only, not limitation.

The terms "first," "second," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

"connected" as used herein is intended to mean an electrical power connection or a signal connection between two components; "coupled" may be a direct connection between two elements, an indirect connection between two elements through an intermediary (e.g., a wire), or an indirect connection between three elements.

Example 1

As shown in fig. 1 and 2, an embodiment of the present invention provides a control method of a pneumatic balance control device, the pneumatic balance control device is used for balancing pneumatic pressure of a hydraulic oil tank 7, the pneumatic balance control device includes a hydraulic system and a breather valve 5, the hydraulic oil tank 7 is used for providing hydraulic liquid for the hydraulic system, the breather valve 5 is used for balancing gas pressure in the hydraulic oil tank 7, and the control method includes:

detecting working state parameters of the hydraulic oil tank 7; determining control parameters of the breather valve 5 according to working state parameters of the hydraulic oil tank 7; and controlling the action of the breather valve 5 according to the control parameter of the breather valve 5 so as to balance the gas pressure in the hydraulic oil tank 7. The working state parameters of the hydraulic oil tank 7 are used for controlling the breather valve 5, so that the adjustment mode for balancing the gas pressure in the hydraulic oil tank 7 can be carried out according to the actual environment, the control accuracy is improved, and the problem of air pressure balance in the hydraulic oil tank can be better solved.

In a possible embodiment, as shown in fig. 1 and 3, in order to better balance the gas pressure in the hydraulic oil tank 7, the operating state parameters of the hydraulic oil tank 7 include: the temperature parameters and the gas pressure parameters of the hydraulic liquid in the hydraulic oil tank 7; a control method of an air pressure balance control device comprises the following steps:

determining control parameters of the breather valve 5 according to the temperature parameters and the gas pressure parameters of the hydraulic liquid in the hydraulic oil tank 7; and controlling the action of the breather valve 5 according to the control parameter of the breather valve 5 so as to balance the gas pressure in the hydraulic oil tank 7. The control parameters of the breather valve 5 are determined by specifically adopting the temperature and the air pressure of the hydraulic fluid to the working state parameters of the hydraulic oil tank 7, so that the influence of bubbles separated from the hydraulic fluid by gas in the hydraulic fluid (such as hydraulic oil) on the pressure in the hydraulic oil tank 7 can be solved. Specifically, the control parameter of the breather valve 5 may be the opening degree of the breather valve 5, the control parameter of the breather valve 5 is determined by the temperature and the air pressure of the hydraulic fluid, and the control parameter may be determined according to the corresponding relationship between the temperature and the air pressure of the hydraulic fluid and the opening degree of the breather valve 5, so that the opening degree control of the breather valve 5 is more accurate, and the accuracy of the pressure balance of the hydraulic oil tank 7 is improved.

In another possible embodiment shown in fig. 1 and 4, in order to better balance the gas pressure in the hydraulic oil tank 7 and simplify the control process, the detecting of the operating state parameter of the hydraulic oil tank 7 includes: detecting a gas pressure parameter in the hydraulic oil tank 7; the detection of the gas pressure parameter in the hydraulic tank 7 also allows the detection of the air pressure in the hydraulic tank 7 according to the hydraulic stroke of the hydraulic cylinder 4 of the hydraulic system. Then, the control parameter of the breather valve 5 (such as the opening degree of the breather valve 5) is determined according to the gas pressure parameter of the hydraulic oil tank 7, and the breather valve 5 is controlled to act according to the control parameter of the breather valve 5 so as to balance the gas pressure in the hydraulic oil tank 7. The control mode can be suitable for the working condition that the hydraulic oil tank 7 is influenced by the gas pressure parameter in the hydraulic oil tank 7 so as to simplify the control reference variable. The idea of the scheme is that the stroke state of the hydraulic cylinder is converted into the air pressure in the hydraulic oil tank 7 due to the volume change of hydraulic oil, so that the gas pressure parameters in the hydraulic oil tank 7 are better balanced. According to the scheme, the volume change of the corresponding hydraulic oil cylinder is determined by detecting the stroke of the hydraulic oil cylinder and calculating the use volume of the hydraulic oil, so that the gas pressure parameter (such as air pressure) in the hydraulic oil tank 7 caused by the hydraulic stroke is detected. This allows the gas pressure in the hydraulic reservoir 7 to be balanced normally in the event of a failure of the gas pressure sensor in the hydraulic reservoir 7. The hydraulic oil cylinders in the working device can act simultaneously, and the stroke of the hydraulic oil cylinder can be the sum of the strokes of all or part of the oil cylinders in the working device.

As shown in fig. 1 and 5, in another possible embodiment, the control method of the air pressure balance control device provided by the present invention further includes:

acquiring the working state of a driving mechanism in a hydraulic system, and determining the driving state of the hydraulic system according to the working state of the driving mechanism;

and determining the control parameters of the breather valve 5 according to the working state parameters of the hydraulic oil tank 7 and the driving state of the hydraulic system.

Specifically, the operating state parameters of the hydraulic oil tank 7 include: the temperature parameters and the gas pressure parameters of the hydraulic liquid in the hydraulic oil tank 7; if the driving state of the hydraulic system is the driving state of the hydraulic cylinder and the temperature parameter of the hydraulic liquid in the hydraulic oil tank 7 is kept constant within a preset time period, determining the control parameter of the breather valve 5 according to the gas pressure parameter in the hydraulic oil tank 7;

and if the driving state of the hydraulic system is the driving state of the hydraulic motor and the gas pressure parameter in the hydraulic oil tank 7 is kept constant within a preset time period, determining the control parameter of the breather valve 5 according to the temperature parameter of the hydraulic liquid in the hydraulic oil tank 7. The preset time is preferably set according to test experience. The control parameter (opening degree) of the breather valve 5 determined according to the hydraulic liquid temperature parameter can be determined through a direct proportional relation data table or a discrete relation data table between the hydraulic liquid temperature parameter and the control parameter of the breather valve 5, for example, when the constant air pressure P1 is in a state, the detected temperature T1 is applied to the relation data table to obtain that the opening degree of the breather valve 5 is K1, and then the opening degree is output to an electro proportional valve in the breather valve 5, and the electro proportional valve is adjusted to the corresponding opening degree, so that the air entering or exiting the hydraulic oil tank 7 is balanced.

The specific scheme for acquiring the working state of the driving mechanism in the hydraulic system and determining the driving state of the hydraulic system according to the working state of the driving mechanism is as follows:

the drive mechanism in this embodiment is mainly implemented by a hydraulic cylinder and a hydraulic motor. The working state of the hydraulic cylinder can be detected by the distance sensor, and the working state of the hydraulic cylinder can be judged by detecting whether the detection data of the distance sensor exists or not; the working state of the hydraulic motor can be judged by acquiring an electrifying signal of a control valve on a control loop of the hydraulic motor; when only the hydraulic cylinder is in a working state, determining that the driving state of the hydraulic system is a hydraulic cylinder driving state; when only the hydraulic motor is in the working state, the driving state of the hydraulic system is determined to be the hydraulic motor driving state.

Furthermore, when the driving state of the hydraulic system is the hydraulic cylinder driving state, no matter the hydraulic cylinder is in the large chamber stroke state or the small chamber stroke state, if the temperature parameter of the hydraulic liquid in the hydraulic oil tank 7 is kept constant within a preset time period (such as 2 seconds), the control parameter of the breather valve 5 can be determined according to the gas pressure parameter in the hydraulic oil tank 7, so that the control environment is further classified, and the balance effect of the gas pressure in the hydraulic oil tank 7 can be improved.

When the driving state of the hydraulic system is the hydraulic motor driving state, no matter the hydraulic motor is in the forward rotation state or the reverse rotation state, for example, the gas pressure parameter in the hydraulic oil tank 7 is kept constant within a preset time period (for example, 2 seconds), the control parameter of the breather valve 5 can be determined according to the hydraulic liquid temperature parameter in the hydraulic oil tank 7. This further classification of the control environment can improve the effect of balancing the gas pressure in the hydraulic oil tank 7. The control parameter (opening degree) of the breathing valve 5 determined according to the gas pressure parameter in the hydraulic oil tank 7 can be determined by a direct proportional relation data table or a discrete relation data table between the hydraulic liquid gas pressure parameter and the opening degree of the breathing valve 5, for example, when the constant temperature T2 is in a state, the detected gas pressure parameter P2 is used in the relation data table to obtain the opening degree value K2 of the breathing valve 5, and then the opening degree value is output to an electric proportional valve in the breathing valve 5, and the electric proportional valve is adjusted to the corresponding opening degree, so that the air entering or exiting the hydraulic oil tank 7 is balanced.

The breathing valve 5 comprises an electro proportional valve and a filter, and the control parameter of the breathing valve 5 is determined, preferably the opening parameter of the electro proportional valve is determined. Air is dissolved in general liquid, and 6-12% volume of air is dissolved in hydraulic oil. At a certain temperature, when the hydraulic oil pressure is lower than a certain value, gas dissolved in the oil is suddenly and rapidly separated from the oil, and a large number of bubbles are generated, wherein the pressure is called the air separation pressure of the oil at the temperature. The air separation pressure is related to the type of the hydraulic medium and also to the temperature and the amount of dissolved air, and the higher the temperature, the greater the amount of dissolved air, the higher the air separation pressure. The data table of the correspondence relationship between the operating state parameter in the high hydraulic oil tank 7 and the opening parameter of the electro proportional valve under the different control conditions, such as the correspondence relationship between the air separation pressure and the temperature, the correspondence relationship between the gas pressure parameter and the opening parameter of the electro proportional valve, and the correspondence relationship between the gas pressure parameter, the hydraulic fluid temperature parameter, and the opening parameter of the electro proportional valve, is stored in the controller in advance through data. Preferably, the corresponding relationship is subjected to data fitting to obtain a corresponding functional relationship, and the functional relationship is stored in the controller.

Through the control parameters, the opening (closing) amount of the breather valve is accurately controlled, precipitation of air in hydraulic oil is facilitated, and the service lives of the hydraulic oil and the hydraulic element are prolonged. The logical relations are fed back to the controller according to signals collected by the sensors, and the signals are automatically adjusted by the controller.

As shown in fig. 1, the present embodiment further provides a control system of a pneumatic balance control device, the pneumatic balance control device is used for pneumatic balance of a hydraulic oil tank 7, the pneumatic balance control device includes a hydraulic system and a breather valve 5, the hydraulic oil tank 7 is used for providing hydraulic liquid for the hydraulic system, the breather valve 5 is used for balancing gas pressure in the hydraulic oil tank 7, and the control system includes:

the detection device is used for acquiring working state parameters of the hydraulic oil tank 7;

the controller is used for determining the control parameters of the breather valve 5 according to the working state parameters of the hydraulic oil tank 7; and controlling the breathing valve 5 to act according to the control parameter of the breathing valve 5 so as to balance the gas pressure in the hydraulic oil tank 7.

Preferably, the breather valve 5 comprises: an electro-proportional valve having a first inlet port and a second inlet port and a filter; wherein the filter is in communication with a first inlet port of an electro proportional valve, a second inlet port of which is in communication with the hydraulic tank 7. The filter can filter the air entering the hydraulic oil tank, prevent dust from entering the oil tank, and prevent the hydraulic oil from being polluted and deteriorated. The selection of the electro-proportional valve can meet the requirement of the accurate control of the control method, so that the air in the hydraulic oil is controlled to be accurately separated out, and the service lives of the hydraulic part and the hydraulic oil are prolonged.

The detection device includes: a detection unit and a temperature sensor 8;

the detection unit is used for detecting gas pressure parameters in the hydraulic oil tank 7;

the temperature sensor 8 is used for detecting the temperature parameter of the hydraulic liquid in the hydraulic oil tank 7;

the controller is used for determining the control parameters of the breather valve 5 according to the temperature parameters of the hydraulic liquid in the hydraulic oil tank 7 and the air pressure parameters in the hydraulic oil tank 7.

As shown in fig. 1, the hydraulic system includes a main valve 2, a hydraulic pump 1, and a hydraulic cylinder 4; the hydraulic pump 1 draws a corresponding hydraulic fluid, such as hydraulic oil, from the hydraulic oil tank 7, supplies the hydraulic oil to the hydraulic cylinder 4 through the main valve 2, and returns to the hydraulic oil tank 7 through the main valve 2.

Preferably, the detection unit detects the air pressure in the hydraulic tank 7 by means of the hydraulic stroke taken from the hydraulic cylinder 4 of the hydraulic system. Optionally, the detection unit includes a stroke sensor 3 and a first controller, and the stroke sensor 3 is configured to detect a hydraulic stroke of the hydraulic cylinder 4; the first controller calculates the use volume of the hydraulic oil according to the hydraulic stroke to determine the volume change of the corresponding hydraulic oil cylinder. Thereby detecting a gas pressure parameter in the hydraulic tank 7 caused by the hydraulic stroke.

Optionally, for convenience of detection, the detection unit may be further independently set as the air pressure sensor 6, and the air pressure parameter in the hydraulic oil tank 7 is directly detected by the air pressure sensor 6, so that the air pressure parameter in the hydraulic oil tank 7 can be rapidly measured.

Alternatively, the detection unit may be provided as both the stroke sensor 3 and the first controller, and the air pressure sensor 6. Due to the redundant arrangement, the situation that the gas pressure parameter in the hydraulic oil tank 7 cannot be acquired when the gas pressure sensor 6 breaks down can be avoided.

The hydraulic system comprises a driving mechanism; the driving mechanism comprises a hydraulic cylinder and a hydraulic motor;

the controller is also used for acquiring the working state of a driving mechanism in the hydraulic system and determining the driving state of the hydraulic system according to the working state of the driving mechanism;

and determining the control parameters of the breather valve 5 according to the working state parameters of the hydraulic oil tank 7 and the driving state of the hydraulic system.

Specifically, the operating state parameters of the hydraulic oil tank 7 include: the temperature parameters and the gas pressure parameters of the hydraulic liquid in the hydraulic oil tank 7; the controller is specifically used for determining the control parameter of the breather valve 5 according to the gas pressure parameter in the hydraulic oil tank 7 when the driving state of the hydraulic system is the hydraulic cylinder driving state and the temperature parameter of the hydraulic liquid in the hydraulic oil tank 7 is kept constant within a preset time period; when the driving state of the hydraulic system is the hydraulic motor driving state and the gas pressure parameter in the hydraulic oil tank 7 is kept constant within a preset time period, the control parameter of the breather valve 5 is determined according to the hydraulic liquid temperature parameter in the hydraulic oil tank 7.

The embodiment also provides engineering machinery comprising the control system of the air pressure balance control device. The invention takes the working state parameter of the hydraulic oil tank as the control parameter of the breathing valve, and can better balance the gas pressure in the oil tank, thereby prolonging the integral service life of the engineering machinery.

Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the embodiments of the present invention are not limited to the details of the above embodiments, and various simple modifications can be made to the technical solutions of the embodiments of the present invention within the technical idea of the embodiments of the present invention, and the simple modifications all belong to the protection scope of the embodiments of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, the embodiments of the present invention do not describe every possible combination.

In addition, any combination of various different implementation manners of the embodiments of the present invention is also possible, and the embodiments of the present invention should be considered as disclosed in the embodiments of the present invention as long as the combination does not depart from the spirit of the embodiments of the present invention.