CN103353366B - Method for dynamic measurement of contact pressure of friction pair of circular plate - Google Patents
Method for dynamic measurement of contact pressure of friction pair of circular plate Download PDFInfo
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- CN103353366B CN103353366B CN201310316604.2A CN201310316604A CN103353366B CN 103353366 B CN103353366 B CN 103353366B CN 201310316604 A CN201310316604 A CN 201310316604A CN 103353366 B CN103353366 B CN 103353366B
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Abstract
The invention relates to a method for dynamic measurement of a contact pressure of a friction pair of a circular plate. The method comprises the following steps: analyzing a processing technology requirement and a loading structure characteristic of a friction pair; selecting a pin with the same material attribute as a dual disc; determining distribution of the pin at the dual disc and a matched dimension of a dual disc pin hole according to the characteristic of the loading structure; carrying out secondary processing on the surface of the dual disc to obtain an attribute similar to that of an original dual surface; and carrying out strain measurement on the pre-buried pin so as to obtain a contact pressure of the friction pair at the zone. According to the invention, static and dynamic testing on the contact pressure of the friction pair can be carried out; on the premise that a contact state of a surface of the friction pair is not changed, static-dynamic testing of the contact pressure is realized; and when a precise pressure boundary condition of the friction pair is determined, a theoretical basis is provided for the dynamic design of the friction pair.
Description
Technical field
The present invention's one is used for friction pair contact dynamic measurement method, belongs to the secondary pressure of contact surface field of measuring technique of endless-track vehicle transmission field clutch friction.
Background technology
High-energy-density friction driven system is the key of high performance power transmission, and its notable feature is high-power, high rotating speed, and friction pair is widely used in the transmission field of endless-track vehicle due to the wearing quality of its excellence and higher thermal capacitance.Cu base powder metallurgy friction pair, comprises brakes and clutches, is operated in many stress combinational environment, and being the principal element affecting friction pair rubbing characteristics as three bound of parameter-pressure, speed, temperature, is also the important references in design of friction pairs process.Present stage speed and temperature boundary can Measurement accuracy by experiment, and the test of pressure boundary is the Focal point and difficult point in three boundary surveies always, dynamic test is more difficult, never has maturation method that is effective and friction pair pressure of contact surface measurement reliably at present at the design field of Wet-type friction slice.Carrying out that three-dimensional modeling simulation is pressed into contact to friction pair is obtain the Main Means of contact.The method of thin film sensor is puted up owing to changing surface in contact characteristic and can not carry out kinetic measurement in the surface that present stage adopts, and can not adapt to the dynamic design of endless-track vehicle friction pair, cannot meet the designing requirement of new model new equipment friction pair.
The difficulty of surface of friction pair pressure survey for a long time mainly concentrates on following several respects: (1) measuring sensor participates in contact, changes the contact performance of surface in contact, and friction pair actual contact situation can not get reflection, and the measurement of contact is not accurate enough; (2) cannot realize for friction pair from the kinetic measurement being separated, touching sliding overall process of rubbing; (3) because the secondary contact distribution range of wet friction is little, conventional pressure sensitive paper method precision is low, is difficult to the pressure distribution state effectively reflecting surface in contact.
Summary of the invention
Technical matters of the present invention: be the problem cannot measured to solve the friction pair pressure boundary condition that exists in prior art, there is provided a kind of for method for dynamic measurement of contact pressure of friction pair of circular plate, the pressure of contact surface effectively solving current friction pair distributes the difficulty that cannot truly obtain, under being not change the prerequisite of surface of friction pair contact condition, achieve the quiet dynamic test of contact, while determining friction pair accurate pressure boundary condition, for friction pair dynamic design provides theoretical foundation.
Technical solution of the present invention: a kind of for method for dynamic measurement of contact pressure of friction pair of circular plate, performing step is as follows:
Step one, determine the loading structure feature of working condition under friction pair duty and friction pair, obtain the physical dimension of friction pair, require to determine the roughness requirements of friction pair surface in contact and the processing request of surface planarity according to the manufacturability of the friction pair that will measure;
Rapid two, according to the position distribution of the measurement point analyzed in step one on the loading structure feature of friction pair of acquisition and the physical dimension determination friction pair antithesis sheet of friction pair and measuring point quantity N;
Step 3, the Friction Disk Surface roughness obtained according to step one analysis and planarity requirements, require in conjunction with the size of friction pair surface in contact, antithesis sheet thickness, foil gauge size and measuring accuracy the diameter D and the length L that determine pin, defining method is as follows:
Pin diameter D< (R-r)/2, R is antithesis sheet external diameter, and r is antithesis sheet internal diameter; B/2<L<2B/3, B is antithesis sheet thickness, the D of the f pictional surface contacts friction separation of roughness 1.6 flatness 0.04 should not be greater than 12mm, but the minimum width b that should not be less than minimum strain sheet, and the diameter D scope of the pin chosen is: 4-12mm; The pin determining diameter D and length L is embedded into rubbing in the embedded hole of steel disc;
Step 4, the dimensioned pin of pin obtained according to step 3, and a plane is processed on the pin side face of cylinder, be used for pasting foil gauge, the size of processing plane should be greater than the size of foil gauge, in the position of layouting of measured zone needed for antithesis sheet according to the hole D and L determined breaking pre-buried pin, tapping in the pin hole in antithesis sheet noncontact face, attacking the line degree of depth is B-L, chooses the fit dimension tolerance of transition fit as hole and pin;
Step 5, the friction pair material characteristic obtained according to step one, physical dimension characteristic, supporting construction feature, loading feature etc. sets up the three-dimensional simulation model of friction pair and loading structure thereof, three-dimensional model is carried out to the finite element simulation of multi-direction pressure load, for contact tests the prediction of providing fundamental basis with numerical range;
Step 6, the range of stress according to the simulation results determination friction pair surface in contact of step 5, and the major parameter of the resistance strain gage being suitable for this friction structure is determined according to this scope, described major parameter comprises the initial resistance of foil gauge, sensitivity coefficient and strain limit, obtain the foundation of foil gauge selection by major parameter;
Step 7, to be chosen by step 6 and to obtain suitable monitor strain sheet, the foil gauge of strain range being adapted to emulate gained is affixed in plane that pin processes in advance, check that whether foil gauge resistance value is the initial resistance of resistance strain gage, if resistance display is little with the initial resistance difference of resistance strain gage, the success of foil gauge paster is described, bridge joint strain controlling circuit, and pin to be loaded on antithesis sheet in corresponding pin-and-hole and to fix with pre-loading screw;
Step 8, the pairing steel sheet assembled is analyzed according to step one acquisition friction pair production and processing work require secondary processing is carried out to friction pair surface in contact, friction pair is installed on friction wear testing machine and carries out break-in, running-in time is not less than 30min, and running in speed operating mode rotating speed residing for the friction pair analyzing acquisition in step one is determined;
Step 9, sufficient for break-in friction pair is carried out quiet dynamic load, connect resistance-strain Acquisition Instrument, by voltage index gauge zeroing circuit, and by the Signal transmissions of bridgt circuit, obtain the stress-strain state of each measuring point of pre-buried pin place friction surface.
The present invention's advantage is compared with prior art:
(1) the present invention adopts the method for pre-buried pin, realizes the measurement of the quiet dynamic touch pressure of friction pair.
(2) measuring sensor is embedded in friction pair inside by the present invention, and secondary processing surface has similar characteristic to original surface, eliminates the impact of measuring sensor on contact performance itself.
(3) the present invention can realize measuring from the dynamic touch pressure being separated, touching sliding overall process of rubbing for friction pair, and this method can be measured effectively to the dynamic contact characteristic of friction pair.
(4) measuring accuracy of the present invention is high, and measuring method is simple, and test point position arrangement convenience, testing cost is lower.
(5) pressure of contact surface that the present invention effectively solves current friction pair distributes the difficulty that cannot truly obtain, under being not change the prerequisite of surface of friction pair contact condition, achieve the quiet dynamic test of contact, while determining friction pair accurate pressure boundary condition, for friction pair dynamic design provides theoretical foundation.
Accompanying drawing explanation
Fig. 1 is the inventive method realization flow figure;
Fig. 2 is pin-and-hole distribution engineering drawing in the present invention;
Fig. 3 is pin feature engineering drawing in the present invention, and wherein upper figure is front view, and figure below is vertical view;
Fig. 4 is that in the present invention, pin just waits shaft side figure;
Fig. 5 is pin assembling schematic diagram in the present invention;
Fig. 6 is the limit element artificial module set up by practical structures in the present invention;
Fig. 7 is FEM Numerical Simulation cloud atlas in the present invention;
Fig. 8 is the paster front elevation of pin side plane in the present invention;
1, anti-blushing agent 2, first foil gauge 3, lead-in wire 4, hinge (sealed polyethylene plastic), 5, connection terminal, 6 soldered joints, a, plug screw b, pin c, the second foil gauge;
Fig. 9 is the paster plan view of pin side plane in the present invention;
Figure 10 is jackshaft road of the present invention connection layout;
Figure 11 is the experiment curv figure of measuring point in the present invention.
Embodiment
Elaborate below in conjunction with the embodiment of accompanying drawing to the inventive method.
Theoretical research and process of the test all find that Cu base powder metallurgy friction pair also exists the feature of contact skewness (particularly radial) at engaging process and bonding state, and the generation of this feature is because the feature of pressure structure and surface in contact characteristic determine jointly.The present invention adopts the method for pre-buried pin, realizes the measurement of the quiet dynamic touch pressure of friction pair.
In order to realize the test of friction pair contact, processing test pin is some, the requirement of the size according to friction pair, feature, test zone and the precision of pressurizeing is needed for pin size and characteristic distributions and determines, the size of pin diameter is directly connected to the size of the contact area of measurement, and arrangement principle should be taken into account the actual change rule of contact.In order to not affect the truth of the friction surface of Cu based powder metallurgy friction wafer, the surface of pairing steel sheet is beaten several through holes, the end tapping in hole, according to the requirement of paster, foil gauge is affixed on steel pin side, steel pin is put into the through hole of pairing steel sheet, the test pin that stickup strains is embedded in the position that antithesis sheet needs to measure contact, and adopt transition fit between pin and antithesis sheet, end is fixed by plug screw.
The surface embedding pin is carried out secondary processing (being generally grinding) by pairing steel sheet by technological requirement, makes the surface of embedding pin have similar characteristic to former antithesis surface.Friction pair is loaded into friction test platform, and accesses hyperchannel strain measurement system, for the measurement of dynamic contact quiet under different operating mode, need to change sample frequency, to obtain more preferably measurement result.
As shown in Figure 1, the dynamic touch pressure method of testing specific implementation process of the present invention's pre-buried pin strain measurement is as follows:
Step one, determine the manufacturability requirement of friction pair that needs to measure, as agglomerated material requirement, processing technology requirement, comprising the flatness of surfaceness, Friction Disk Surface, such as certain surface of friction pair adopts powder metallurgical sintering process, friction surface grinding, flatness 0.04, roughness 1.6 etc.For the manufacturing processing technic of the analysis mainly antithesis sheet that manufacturability requires, for the selection of the tolerance fit of antithesis sheet secondary processing and pin and pin-and-hole provides foundation.And determine working condition (being mainly load) under friction pair duty; The physical dimension (internal-and external diameter, thickness, frictional layer thickness etc.) of friction disc and loading structure feature, comprise supporting construction feature during friction pair work, pressure structure feature, as which kind of adopts support, and position of bearings and loading force position and direction etc.The analysis of friction pair physical dimension, working condition and loading structure mainly carries out abbreviation to loading structure, and in order to complete the initial analysis of friction pair contact distribution, the foundation for realistic model provides necessary parameter support.
Step 2, determine that (antithesis sheet is the structure rubbed mutually with friction disc to its antithesis sheet according to the feature (friction pair supporting construction feature, loading force position and direction etc.) of the loading structure of the friction pair determined in step one, generally be formed from steel, it and friction disc constitute friction pair jointly) on the distribution of measurement point and measuring point quantity, according to friction pair size and design feature, reasonable Arrangement is carried out to measuring point quantity and distribution.For near supporting construction and the nearer regional stress of distance load(ing) point larger, cause friction pair to be out of shape obviously, cause friction disc and the uneven significantly place of the unilateral pressure distribution of antithesis, should layout more, layout and follow circumferential uniform principle, to reduce the degree of irregularity of circumference; Circumference and radial measuring point and distribution should determine according to testing requirement, and radial pressure test is tested mainly for static(al), and consider that test that circumferential pressure distributes often will realize the effect of kinetic test.In the region that pressure gradient is larger, should consider to arrange measurement point more, layout and require to meet uniform principle as far as possible.The density of layouting should be determined according to the fine degree of friction disc physical dimension and measurement, large scale friction pair can be layouted more, and more measurements of layouting are meticulousr, and layouting is for the purpose of the pressure distribution state understanding Friction Disk Surface, there is no fixing number, be generally no more than 64.Such as support for centre bearing, the friction pair structure of center loaded, should layout at inner ring for layouting of antithesis sheet more;
Step 3, determine diameter D and the length L of pin by physical dimension and according to accuracy requirement, the material of pin is consistent with heat treatment characteristic and pairing steel sheet.After completing friction pair measuring point quantity and distribution character, need according to the size of measured zone and the diameter D of measuring accuracy determination pin and length L, the diameter of pin has certain restriction, and the size of the diameter of pin is directly connected to area size and the accuracy rating of the strain testing on surface.But meticulous pin may bring the adverse consequencess such as difficulty of processing is higher, fit dimension is inaccurate, unrelieved stress is excessive.According to excessively thick pin, the quantity of measuring point will be subject to certain restrictions, and the precision of measurement also can decline.The material of pin, with necessary consistent to the material of the steel disc that rubs, could reflect the pressure distribution situation of Friction Disk Surface so the most truly.
Require according to the size of Friction Disk Surface roughness and flatness, surface of contact, antithesis sheet thickness, foil gauge size and measuring accuracy the diameter D and the length L that determine pin, defining method is as follows:
General pin diameter D< (R-r)/2, R is antithesis sheet external diameter, and r is antithesis sheet internal diameter; B/2<L<2B/3, B is antithesis sheet thickness, the D of the f pictional surface contacts friction separation of general 1.6 roughness 0.04 flatnesses should not be greater than 12mm, and the better D selected is less for exposure level, but the minimum width b that should not be less than minimum strain sheet.The diameter D scope of the pin chosen is generally: 4-12mm;
Need the contact in survey 5 millimeters of point cantact regions, antithesis sheet thickness is that 15mm, L get 12mm, 0.8 roughness, the friction pair of 0.04 flatness, and R is 120mm, r is 100mm, and optional D is 5mm.The material of pin and antithesis dish (friction pair comprise frictional disk and to antithesis dish) and material consistent; The pin determining diameter D and length L can be embedded into rubbing in the embedded hole of steel disc;
Step 4, processing pin need the plane of pasting foil gauge c, a plane is processed on the pin b face of cylinder, be used for pasting foil gauge c, the size of processing plane should be greater than the size of foil gauge, and needed for antithesis sheet, the position of layouting of measured zone is according to the hole D and L determined breaking pre-buried pin, and tapping, as shown in Figure 5, wherein a is plug screw, and b is pin, and c is foil gauge.The length of attacking the line degree of depth and plug screw a should be L
spiral shell=L
sheet-L
pin, wherein L
sheetfor the thickness of pairing steel sheet, L
pinfor pin b length with choose the fit dimension tolerance of transition fit as hole and pin b;
Step 5, the friction pair material characteristic obtained according to step one, physical dimension characteristic, supporting construction, loading feature and the parameters such as measuring point distribution and size set up the three-dimensional simulation model of friction pair and loading structure thereof, and concrete grammar is:
According to the supporting construction of friction pair in ANSYS or ABQUS, dimensional requirements etc. set up three-dimensional model, three-dimensional model material cell attribute is given according to the material properties of friction pair, load according to magnitude of load according to loading structure feature, obtain stable state Finite element analysis results, choose the value of the stress and strain of the Nodes of antithesis dish surface in contact, as the result of calculation of three-dimensional artificial.The foundation of model and the analysis of finite element are the approximate ranges of the pressure distribution in order to obtain friction pair surface in contact, and the selection for follow-up foil gauge provides preliminary foundation.
Step 6, carry out the FEM Numerical Simulation of multidimensional pressure load from three-dimensional model, tentatively determine the ess-strain scope of friction pair surface in contact.The selected point of ess-strain at the Nodes of unit, and radially distributes, and the data area obtained is the scope of pressure.And the major parameter of the resistance strain gage being suitable for this friction structure is determined according to this scope, comprise the initial resistance of foil gauge, sensitivity coefficient and strain limit, according to the foil gauge that parameter choose is suitable, when selecting specification and the form of foil gauge, it should be noted that the material character of component and the stress state of component.What measure because of foil gauge is mean strain, when component stress variation range is larger, generally selects little gauge length foil gauge.(concrete system of selection refers to foil gauge selects pertinent texts).
Step 7, applicable resistance strain gage is affixed on the flat side of pin, check that whether foil gauge resistance value is the initial resistance of resistance strain gage, if resistance display is little with the initial resistance difference of resistance strain gage, the success of foil gauge paster is described, bridge circuit, the wire that B, D end is connected respectively at connection terminal 5 is connected, and A, C end is connected to external stabilization 5V voltage respectively, namely ensures that the voltage between A, C end is stable 5V voltage.The computing formula of its circuit is:
If there is R
1r
3=R
2r
4then E=0, this is the zeroing circuit of foil gauge, and after when resistance is at alteration of form, its resistance value changes, the knots modification of the value of voltage is:
The changes values of resistance can be obtained by above formula, and and then obtain the value of dependent variable according to the resistance characteristic of resistance itself, and gone out the value of pressure again by friction pair material property calculation.Then pin is loaded in pin-and-hole corresponding on pairing steel sheet, use plug screw pretension, complete the assembling of antithesis sheet;
Step 8, the antithesis sheet assembled is required to carry out secondary processing to its surface in contact according to the manufacturability of friction pair in engineering, object reduces the impact of pre-buried pin on contact character of surface, then the antithesis sheet and friction disc that are embedded with pin are installed on friction wear testing machine and carry out break-in, running-in time is not less than 30min, and running in speed operating mode rotating speed residing for friction pair is determined;
Step 9, sufficient for break-in friction pair is loaded according to actual working conditions, loading environment can be static pressure test, also can be dynamically pressure testing (what is called dynamically refers to frictional disk and antithesis dish relative sliding), when carrying out dynamically pressure testing foil gauge link circuit on need to add power up brush, in order to prevent the winding of return wire, on-load pressure is consistent with actual condition load, open resistance-strain Acquisition Instrument, by voltage index gauge zeroing circuit, and by the Signal transmissions of bridgt circuit, collection signal also obtains the stress-strain state of each measuring point of friction surface.The stress-strain measurement value of each measuring point directly reflects the contact condition of friction pair surface in contact, the measured value of the local ess-strain that contact is larger is relatively large, otherwise contact insufficient place, the measured value of ess-strain is relatively little, the method can effectively measure friction disc from released state to contact condition, then to the measurement of the real-time pressure state of sliding state of rubbing and monitoring.
Implementation procedure of the present invention is further illustrated below in conjunction with specific embodiment.
Step one, determine the manufacturability requirement of friction pair that needs to measure, as agglomerated material require, processing technology requirement, comprising the flatness of surfaceness, Friction Disk Surface.Friction material is Cu base powder metallurgy agglomerated material, and choosing internal diameter is Ф 160mm, and external diameter is that the friction pair of Ф 200mm is as research object, the thickness of antithesis sheet is 10mm, and material is 45# steel, surface hardening process, surface processing technique is roughly grind after finish turning, and roughness 0.8, flatness is 0.04.Material is 30CrMnSiA, and heat treatment characteristic is modulation, and hardness is HRC55-60.In order to avoid scantling during secondary processing changes, reserve surplus in steel disc process for last procedure grinding accordingly, the thickness of antithesis sheet is 10.2mm.Hydraulic loaded, pressure limit is 0-20000N, and working temperature is no more than 300K.
Step 2, according to the distribution of the feature determination measurement point of differentiated friction auxiliary structure and measuring point quantity.
In order to measure the state of Radial pressure distribution, choosing measuring point diametrically, as hypothesis contact meets linear distribution diametrically, then choosing two measuring points at close internal-and external diameter place and can meet measurement requirement.If the radial distribution of contact is complicated, then need to select multiple measuring point, the measuring point distribution chosen as shown in Figure 2.
Step 3, the diameter D determining pin according to the requirement of precision and length L, the diameter of pin has certain restriction, selects 30CrMnSiA material diameter D=4mm, length L=5mm.Surfaceness is 1.6, Tempering and Quenching, HRC55-60.As shown in Figure 3, Fig. 4 is just waiting shaft side figure to schematic diagram.
Step 4, punch on steel disc, aperture basic size is 4mm, hole depth 5mm, tapping, screw thread be M4, by attacking line degree of depth L
spiral shell=L
sheet-L
pinthe known tapping degree of depth is 5mm.The fit dimension of hole and pin should be chosen for transition fit H7/k6, as shown in Figure 5, it is inner that a plug screw b pin c foil gauge is all positioned at antithesis dish, what antithesis sheet through hole was positioned at pin location is unthreaded hole, what be positioned at plug screw position is threaded hole, plug screw plays tightening effect to pin, and foil gauge is affixed on the flat side of pin.
Step 5, the friction pair material characteristic obtained according to step one, physical dimension characteristic, supporting construction, loading feature etc. sets up the three-dimensional simulation model of friction pair and loading structure thereof, as shown in Figure 6.The boundary condition of model should be close with physical condition, according to the constraint condition of supporting construction Confirming model, determines the contact type of surface in contact according to operating mode (static friction, sliding friction etc.), and the selection of unit and the size etc. of load applying.
Step 6, three-dimensional model is carried out to the finite element simulation of multidimensional pressure load, tentatively determine the ess-strain scope of friction pair surface in contact.The selected point of ess-strain at the Nodes of unit, and radially distributes, and the data area obtained is the scope of pressure.Simulation result is as shown in Figure 7, by getting a little, as shown in table 1, known at the radially-arranged pressure of friction surface.
The node surface pressure result that table 1 radially distributes
And the major parameter of the resistance strain gage being suitable for this friction structure is determined according to this scope, according to the foil gauge that parameter choose is suitable, the classification of foil gauge is foil, substrate is glass fiber reinforcement synthetic resin, sensitive grid length selects 3mm, version is AA Standard resistance is 350 Ω, and work maximum temperature 80 DEG C, for temperature self-compensation or elastic modulus self compensation.
Step 7, the first foil gauge 2 be applicable to is affixed on the flat side of pin; paster process as shown in Figure 8; paster adopts 502 glue on the sole plane of point position and foil gauge; coat thin layer glue; pinching the first foil gauge 2 draws lead-in wire 3 on the other hand; axix of strain gauge alignment coordinates line; upper cover layer of polyethylene plastic sheeting 4 is as interlayer; with the length direction gently roll extrusion of finger at strainometer; extrudate piece bubble and unnecessary glue; until strainometer and measured object close adhesion, be finally coated with lid layer anti-blushing agent 1 as protection on its surface.
Bridge circuit as shown in Figure 9, usual static strain mensuration twin-core multiply parallel lines.Before welding lead, the two ends of connection terminal 5 are first connected to universal electric meter, check that whether resistance value is the initial resistance of resistance strain gage, 352 Ω are shown as by the prevention of wiring multimeter, the success of foil gauge paster is described, check that wire does not have open circuit, then number ticket is sticked at the connection terminal two ends of each measuring point foil gauge, to show that differentiation causes mistake when avoiding measuring point many, soldering is used to be connected with wire by connection terminal, bridge circuit as shown in Figure 10, B, the wire that D end is connected respectively at connection terminal 5 is connected, A, C end is connected to external stabilization 5V voltage respectively, namely A is ensured, voltage between C end is stable 5V voltage.
Step 8, the pairing steel sheet assembled is carried out secondary grinding according to the manufacturing technique requirent of friction pair to its surface in contact, the surfaceness of pairing steel sheet is worked into 0.8, then the pairing steel sheet and friction disc that are embedded with pin are installed on MM6000 friction wear testing machine and carry out break-in, it is 1500r/min that starting outfit controls rotating speed, time is 30min, on-load pressure is 1MPa, and cooling flow is 4ml/mm
2s.
Step 9, load according to actual working conditions, on-load pressure is: 0.886MPa, zeroing circuit, and the computing formula of zeroing circuit is:
If there is R
1r
3=R
2r
4then E=0, this is the zeroing circuit of foil gauge, and after when resistance is at alteration of form, its resistance value changes, the knots modification of the value of voltage is:
Complete the measurement to pressure state by the change of measuring voltage value, by electric wire strain gauge, magnitude of voltage is transferred to signal processing and analysis device, by signal processing and analysis system, corresponding change in voltage is converted into strain, and calculate stress by elasticity modulus of materials E.The data result curve obtained as shown in figure 11, with the increase of radius, stress value measured by measuring point is on a declining curve, this is the impact of loading structure for pressure contact condition, for the minor fluctuations in curve, then the impact embodied due to surface processing technique feature (roughness, flatness) causes.
Test known the present invention by experiment and effectively can measure the quiet dynamic touch pressure of friction pair, experimental result has carried out preliminary identification to simulation result, for the accurate acquisition of friction pair pressure boundary condition and dynamic design approach provide test support.
The content be not described in detail in instructions of the present invention belongs to the known prior art of professional and technical personnel in the field.
Claims (1)
1., for a method for dynamic measurement of contact pressure of friction pair of circular plate, it is characterized in that performing step is as follows:
Step one, determine the loading structure feature of working condition under friction pair duty and friction pair, obtain the physical dimension of friction pair, require to determine the roughness requirements of friction pair surface in contact and the processing request of surface planarity according to the manufacturability of the friction pair that will measure;
Rapid two, according to the position distribution of the measurement point analyzed in step one on the loading structure feature of friction pair of acquisition and the physical dimension determination friction pair antithesis sheet of friction pair and measuring point quantity N;
Step 3, the Friction Disk Surface roughness obtained according to step one analysis and planarity requirements, require in conjunction with the size of friction pair surface in contact, antithesis sheet thickness, foil gauge size and measuring accuracy the diameter D and the length L that determine pin, defining method is as follows:
Pin diameter D< (R-r)/2, R is antithesis sheet external diameter, and r is antithesis sheet internal diameter; B/2<L<2B/3, B are antithesis sheet thickness, and the diameter D scope of the pin chosen is: 4-12mm; The pin determining diameter D and length L is embedded in the embedded hole to antithesis sheet;
Step 4, the dimensioned pin of pin obtained according to step 3, and a plane is processed on the pin side face of cylinder, be used for pasting foil gauge, the size of processing plane should be greater than the size of foil gauge, in the position of layouting of measured zone needed for antithesis sheet according to the pin hole D and L determined breaking pre-buried pin, tapping in the pin hole in antithesis sheet noncontact face, attacking the line degree of depth is B-L, chooses the fit dimension tolerance of transition fit as hole and pin;
Step 5, the friction pair material characteristic obtained according to step one, physical dimension characteristic, supporting construction feature, loading structure feature sets up the three-dimensional simulation model of friction pair and loading structure thereof, three-dimensional simulation model is carried out to the finite element simulation of multi-direction pressure load, for contact tests the prediction of providing fundamental basis with numerical range;
Step 6, the range of stress according to the simulation results determination friction pair surface in contact of step 5, and the resistance strain gage that is applicable to is selected according to this range of stress, its major parameter comprises the initial resistance of foil gauge, sensitivity coefficient and strain limit;
Step 7, to be chosen by step 6 and to obtain suitable monitor strain sheet, foil gauge is affixed in plane that pin processes in advance, check that whether foil gauge resistance value is the initial resistance of resistance strain gage, if resistance display is little with the initial resistance difference of resistance strain gage, the success of foil gauge paster is described, bridge joint strain controlling circuit, and pin to be loaded on antithesis sheet in corresponding pin hole and to fix with pre-loading screw;
Step 8, the antithesis sheet assembled is analyzed according to step one acquisition friction pair production and processing manufacturability require secondary processing is carried out to friction pair surface in contact, friction pair is installed on friction wear testing machine and carries out break-in, running-in time is not less than 30min, and running in speed operating mode rotating speed residing for the friction pair analyzing acquisition in step one is determined;
Step 9, sufficient for break-in friction pair is carried out quiet dynamic load, connect resistance-strain Acquisition Instrument, by voltage index gauge zeroing circuit, and by the Signal transmissions of bridgt circuit, obtain the stress-strain state of each measuring point of pre-buried pin place friction surface.
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| CN105973737A (en) * | 2016-04-28 | 2016-09-28 | 辽宁科技学院 | Method for obtaining wearing capacity of friction plate |
| CN105973508A (en) * | 2016-04-28 | 2016-09-28 | 辽宁科技学院 | Resistance strain gauge bonding and calibration method capable of measuring contact pressure of disc friction pair |
| CN105953953A (en) * | 2016-04-28 | 2016-09-21 | 辽宁科技学院 | Pin embedded measuring method for tapered friction pair contact pressure |
| CN105758564A (en) * | 2016-04-28 | 2016-07-13 | 辽宁科技学院 | Blind hole surface mounting measuring method used for shear stress of conical friction pair |
| CN114483817B (en) * | 2021-11-23 | 2024-02-27 | 株洲时代新材料科技股份有限公司 | Torque limiter and assembly method thereof |
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| CN201508304U (en) * | 2009-09-27 | 2010-06-16 | 刘学耕 | Dry/wet-type test stand with frictional-wear performance |
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| JPS6159234A (en) * | 1984-08-31 | 1986-03-26 | Kyowa Dengiyou:Kk | Wall surface friction stress-meter |
| LT5624B (en) * | 2008-02-29 | 2010-01-25 | Lietuvos �em�s �kio universitetas, , | Device for measurement of the influence of friction force on the wear characteristics of material surface |
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| 大功率重载摩擦元件磨损率的分形预测方法;王延忠等;《润滑与密封》;20121031;第37卷(第10期);第1-5页 * |
| 湿式多片离合器翘曲特性模拟与试验;孙冬野等;《重庆大学学报》;20100531;第33卷(第5期);第1-6页 * |
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