CN113464512B - Method for measuring erosion fillet of valve core and valve sleeve of servo valve - Google Patents
Method for measuring erosion fillet of valve core and valve sleeve of servo valve Download PDFInfo
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- CN113464512B CN113464512B CN202110778020.1A CN202110778020A CN113464512B CN 113464512 B CN113464512 B CN 113464512B CN 202110778020 A CN202110778020 A CN 202110778020A CN 113464512 B CN113464512 B CN 113464512B
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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
- F15B13/021—Valves for interconnecting the fluid chambers of an actuator
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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
- F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
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- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
- Sliding Valves (AREA)
Abstract
The invention relates to a method for measuring erosion fillets of a valve core and a valve sleeve of a servo valve, which comprises the following steps of: 1) carrying out pneumatic match grinding curve mapping on a servo valve to be measured, and respectively obtaining pneumatic match grinding curves before and after abrasion; 2) acquiring an overlap amount z according to a pneumatic match grinding curve before abrasion; 3) and fitting according to the abraded pneumatic abrasion distribution curve to obtain a valve port fillet r. Compared with the prior art, the method is simple, the calculated amount is small, and the fillet of the valve core and the valve sleeve does not need to be directly measured.
Description
Technical Field
The invention relates to the technical field of hydraulic valves, in particular to a method for measuring erosion fillets of a valve core and a valve sleeve of a servo valve.
Background
The valve port of the hydraulic valve is inevitably eroded by pollutants in oil liquid in the service process, so that the volume of the valve port is lost and the valve port is rounded, and the performance of the sliding valve is irreversibly degenerated. After the valve port generates a fillet, the gradient of the valve port area near the zero position of the slide valve is changed greatly, and the flow gain, the pressure gain, the leakage amount and the like of the slide valve are all influenced obviously. Therefore, the erosion fillet of the slide valve is paid attention to in hydraulic valves, particularly high-end hydraulic valves such as proportional valves and servo valves, and needs to be strictly ensured in the service process, so that the method for measuring the erosion fillet is an important technology.
At present, in the practical process, whether the valve core and the valve sleeve of the slide valve meet the replacement standard is not directly judged through erosion of a fillet, but is judged through factors such as leakage quantity and the like. However, because the leakage factors inside the slide valve are too many, besides the slide valve, the slide valve also comprises a prestage, seals at various positions and the like, and whether the slide valve fails or not is judged by the leakage amount, so that it is more important to directly judge whether the erosion fillet of the valve core and the valve sleeve reaches the failure standard or not, but the erosion fillet of the slide valve is often smaller, the erosion fillet in the electro-hydraulic servo valve is only tens of micrometers at most, the measurement is difficult, at present, the surface profile of the valve core is firstly drawn by a profile measuring instrument during the measurement, and the size of the erosion fillet is determined by a computer analysis means, so that the operation process is complex and not fast.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a method for measuring the erosion fillet of a valve core and a valve sleeve of a servo valve.
The purpose of the invention can be realized by the following technical scheme:
a method for measuring an erosion fillet of a valve core and a valve sleeve of a servo valve comprises the following steps:
1) carrying out pneumatic match grinding curve mapping on a servo valve to be measured, and respectively obtaining pneumatic match grinding curves before and after abrasion;
2) acquiring an overlap amount z according to a pneumatic match grinding curve before abrasion;
3) and fitting according to the abraded pneumatic abrasion distribution curve to obtain a valve port fillet r.
In the step 1), for the pneumatic wear distribution curve before wear, when the valve core displacement is large, the pneumatic wear distribution curve is approximately a straight line, and the expression of the straight line is as follows:
Q x ＝K 1 (x v -z)
wherein Q is x For choke gas flow, K 1 Proportional coefficient before wear, x v Is the spool displacement.
In the step 2), the value corresponding to the intersection point of the extended straight line segment in the pneumatic match grinding curve before abrasion and the horizontal axis is the numerical value of the overlap amount z.
In the step 1), for the worn servo valve, in the section with larger displacement of the valve core, the curve expression is approximated as:
wherein, K 2 To a proportional coefficient after wear, Q x For choke gas flow, x v Is the spool displacement.
The overlap amount z is determined by the valve core valve sleeve during production and processing, and the value is unchanged before and after abrasion.
The proportion coefficient K after abrasion 2 Determined by the slope of the curve at the maximum point of spool displacement.
The servo valve is in a four-side sliding valve type with a full-circumference opening.
Compared with the prior art, the invention has the following advantages:
only a proportionality coefficient K exists between the gas flow and the valve core position in a section with larger valve core displacement on a worn pneumatic match grinding curve 2 Three undetermined parameters of the overlap amount z and the fillet r, wherein the overlap amount z can be determined by a pneumatic grinding curve before abrasion, K 2 The method can be determined through the slope of the curve, so that only one parameter fillet r value needs to be determined, and the fillet r value can be obtained by enabling the flow expression of the worn pneumatic wear distribution curve to be superposed with the experimentally measured pneumatic wear distribution curve through data fitting. The method can directly obtain the erosion fillet radius only by performing data fitting through a section with larger displacement of the valve core in the pneumatic wear-matching curve (pneumatic wear-matching curve) of the valve core and the valve sleeve.
Drawings
FIG. 1 is a schematic view of a four-sided slide valve with a full peripheral opening according to an embodiment.
FIG. 2 is a schematic diagram of a pneumatic wear-leveling curve mapping device for a slide valve pair.
FIG. 3 is a geometric relationship between orifice width and spool displacement.
FIG. 4 is a schematic diagram of the pneumatic wear distribution curve before and after valve port wear.
FIG. 5 shows pneumatic wear distribution curves of slide valve pairs before and after a servo valve test and the fitting results thereof.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
Examples
The invention provides a method for measuring erosion fillets of a valve core and a valve sleeve of a servo valve, which is characterized in that a power-level slide valve structure of a certain servo valve is shown in figure 1, a four-edge slide valve with a full-circumference opening is adopted, in the figure, when the valve core is positioned at a left position, high-pressure oil enters a valve cavity from a P port (a valve sleeve inlet) through a throttling port A1, and oil output by a load enters the valve cavity from a load oil port S2 and flows out from a T port (a valve sleeve outlet) through a throttling port A2; when the valve core is positioned at the right position, the ports A1 and A2 are closed, and the ports B1 and B2 are opened. The sizes of the flow fields near the 4 throttling ports are basically the same; depending on the direction of flow of the liquid stream, the 4 orifices can be divided into two types: the liquid flow at the throttles A1 and B1 flows from the valve sleeve opening to the valve cavity through the throttles; and fluid flow at the a2 and B2 orifices flows from the valve chamber through the orifices to the valve housing outlet. In a servo valve, the materials of the valve core and the valve sleeve are generally consistent, and the abrasion fillets generated by the valve core and the valve sleeve are approximately the same, and are defined as r in the example.
As shown in fig. 2, fig. 2 is a schematic diagram of a pneumatic wear-matching curve mapping device of a slide valve pair, wherein an oil supply port P and an oil return port T of a servo valve are both connected with a constant-pressure air source; the load oil ports S1 and S2 are communicated with the atmosphere through float flowmeters respectively; rotating the adjusting screw to change the position of the valve core; by taking the reading of the dial indicator as an abscissa and the reading of the corresponding float flowmeter as an ordinate, the gas flow-valve core displacement curves (pneumatic wear-matching curves) of the four throttling ports A1, A2, B1 and B2 can be respectively obtained.
The gas flow equation for the orifice is:
in the formula, Q x Is the choke gas flow; p is a radical of 1 Is the air supply pressure; p is a radical of 2 Is atmospheric pressure; t is 1 Is the temperature of the supplied air; c is the flow coefficient of the valve port of the slide valve; r is a gas constant; k is the adiabatic index; w is the valve port area gradient. Valve port inlet gas pressure p 1 And outlet gas pressure p 2 Are all constant values, therefore, the gas flow rate Q x And the width x of the orifice k The relationship is linear, so the above equation can be expressed in a simplified form as:
Q x ＝Kx k (2)
in the formula, K is a proportionality coefficient, considering the radial clearance s of the valve port, the covering amount z and the valve port fillet r,and the width x of the orifice k And spool displacement x v The geometrical relationship between them is shown in fig. 3 and can be expressed as:
so the gas flow and the valve core displacement x v Can be represented as:
the radial clearance s of the slide valve pair is smaller, the valve port fillet of a new valve is smaller, and the radial clearance s can be ignored when the valve core displacement is larger, and then the formula (4) can be simplified as follows:
in the formula, K 1 And K 2 The proportional coefficients before and after abrasion are respectively, and the equation (5) is a theoretical gas flow-valve core displacement curve (pneumatic match grinding curve) because the experimental conditions before and after abrasion are different and not completely consistent.
From equation (5), the curve of gas flow versus valve core displacement for a new valve before wear is determined by the proportionality coefficient K only when the valve core displacement is large 1 And determining the overlap amount z, as shown in fig. 4, by extending a straight line segment on the gas flow rate-spool displacement curve to obtain an intersection point of the straight line segment and an abscissa, the overlap amount z can be determined. For the worn slide valve pair, the gas flow-valve core displacement curve is formed by a proportionality coefficient K 2 The overlapping amount z and the round angle r are determined, the overlapping amount of the valve core and the valve sleeve is determined by production and processing and cannot change along with time, so that only the proportionality coefficient K exists 2 And the round angle r needs to be determined. The proportionality coefficient can be approximately determined by the slope of the curve of the maximum point of the valve core displacement (the larger the valve core displacement is, the smaller the influence of the valve core displacement on the slope of the curve is, and the closer to the proportionality coefficient K is 2 ). Theoretical gas flow-valve core by fitting parameter r valueThe displacement curve is superposed with the gas flow-valve core displacement curve measured by the test, and the fillet size of the valve port can be obtained.
By the valve port fillet analysis method, the positive overlapping quantities of the valve ports 1 to 4 are respectively 15.8 microns, 15.0 microns, 13.7 microns and 13.6 microns, the sizes of fillets of the four valve ports after 200h durability test are respectively 7.6 microns, 5.1 microns, 9.6 microns and 8.8 microns, comparison of theoretical curves of gas flow and valve core displacement before and after the test and test results is shown in figure 5, the fitting effect is good, and the analysis result of erosion fillets is accurate and reliable.
Claims (4)
1. A method for measuring an erosion fillet of a valve core and a valve sleeve of a servo valve is characterized by comprising the following steps:
1) the method comprises the following steps of carrying out pneumatic match grinding curve mapping on a servo valve to be measured, respectively obtaining pneumatic match grinding curves before and after abrasion, and for the pneumatic match grinding curve before abrasion, when the displacement of a valve core is large, the pneumatic match grinding curve is approximate to a straight line, and the expression of the straight line section is as follows:
Q x ＝K 1 (x v -z)
wherein Q is x For throttle gas flow, K 1 Proportional coefficient before wear, x v Is the displacement of the valve core;
for a worn servo valve, in a section with a large displacement of the valve core, the curve expression is approximated as:
wherein, K 2 To a proportional coefficient after wear, Q x Is the choke gas flow, x v Is the displacement of the valve core;
2) acquiring an overlap amount z according to the pneumatic match grinding curve before abrasion, wherein a value corresponding to an intersection point of a lengthened straight line section in the pneumatic match grinding curve before abrasion and a horizontal axis is a numerical value of the overlap amount z;
3) and fitting according to the abraded pneumatic abrasion distribution curve to obtain a valve port fillet r.
2. The method as claimed in claim 1, wherein the overlap z is determined by the production process of the spool valve sleeve, and the value is unchanged before and after abrasion.
3. The method as claimed in claim 1, wherein the worn proportionality coefficient K is measured by measuring the erosion radius of the spool and the sleeve of the servo valve 2 Determined by the slope of the curve at the maximum point of spool displacement.
4. The method as claimed in claim 1, wherein the servo valve is in the form of a four-sided valve spool valve with a full circumference opening.
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Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| DE102008015391A1 (en) * | 2008-03-20 | 2009-09-24 | Robert Bosch Gmbh | Pneumatic slide valve, has valve slide working together at two ends with fixed bearing bushes that are arranged to valve housing for execution of axial guide function, so that dynamic seals exercise sealing function against valve housing |
| CN102375939B (en) * | 2011-11-01 | 2016-02-24 | 北京航空航天大学 | Wear and tear to the analytical approach of its performance impact in a kind of jet pipe servo valve |
| CN105653798A (en) * | 2015-12-30 | 2016-06-08 | 中国航空综合技术研究所 | Method for obtaining fillet contamination wear performance degradation of electro-hydraulic servo valve |
| US11608840B2 (en) * | 2018-08-21 | 2023-03-21 | Michael Yuan | Piezoelectric ring bender servo valve assembly for aircraft flight control actuation and fuel control systems |
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Non-Patent Citations (2)
| Title |
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| 訚耀保等.正开口气动伺服阀控缸匀速运动时的负载特性.《流体传动与控制》.2013,(第02期),全文. * |
| 陈吉红等.滑阀副配磨参数测量的理论研究.《国防科技大学学报》.1991,(第01期),全文. * |
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