Summary of the invention
Technical problem to be solved in the utility model provides a kind of friction and wear behavior testing machine of friction material, but especially provide new structure additional inertial, do not adopt 1: 1 assembly in kind and adopt contract than sample, have with the same or similar function of inertia bench testing machine, and can adopt a kind of friction test machine for small sample contracting ratio table with inertia bench test identical test method standard.
Consult Fig. 1, for solving the problems of the technologies described above, the utility model is taked following technical scheme, promptly in existing frame, dust arrester, cooling device, on the basis of computer control system and electric-control system, the spindle drive systems that will be used to simulate different inertia and the operating condition of test of different rotating speeds is provided is fixed on the last workplace of support, to be used for the last workplace that also is installed in support of determining that the tested friction material test specimen and the slide unit system of friction brake disk relative position are connected and can vertically move by vertically moving dull and stereotyped feather key key, the main axis of the spindle drive systems after the installation relative to the distance of the last workplace of support be installed in the slide unit system in the distance of last workplace of the horizontal relative support of axis that moves the pressure bearing head on the flat board equal and two axial lines is parallel.
Spindle drive systems described in the technical scheme is made up of the flywheel gear of friction brake disk, drive motor, temperature measuring equipment, rotation-speed measuring device and simulated inertia; What described drive motor adopted is the double output shaft motor, and motor right side projecting shaft connects the axle sleeve flange that the installation flywheel is housed by key, and the flywheel group is fixedlyed connected with the axle sleeve flange that flywheel is installed.
Described temperature measuring equipment includes the axle sleeve flange that is fixed with friction brake disk that connects suit on the projecting shaft of drive motor left side by key, be sleeved on the heat-barrier material on the axle sleeve flange outside surface from left to right successively, the heat-barrier material fixed head, insulation sleeve, copper ring, stop washer, clamp nut, little profile of tooth belt wheel tests the speed, and the thermopair detecting head is fixed in the axial aperture of friction brake disk, the other end of thermopair passes through heat-barrier material, the heat-barrier material fixed head, square molded lines groove on the axle sleeve flange outside surface is drawn with the copper ring inner ring surface affixed, outer ring surface of copper ring and the carbon brush sliding contact that is fixed on the carbon brush fixed head.
The described measurement mechanism that is used to measure the speed of mainshaft is the shell that is fixed on drive motor by mounting bracket, at first rotation axis is packed in the axle sleeve with bearing, it is packed on the mounting bracket that is fixed on the drive motor shell again, the big profile of tooth belt wheel that tests the speed is contained in the left end of rotation axis by the key adapter sleeve, photoelectric encoder is fixed on the axle sleeve right-hand member, the photoelectric encoder axle that tests the speed links to each other with rotation axis by screw thread, and the big profile of tooth belt wheel that tests the speed is connected with little profile of tooth belt wheel band on the spindle drive systems by cog belt.
Slide unit system described in the technical scheme by slide unit, the measurement mechanism that is used for loading force arm assembly, pressure control charger, friction force or moment of friction that tested friction material test specimen installs and fixes forms; Described slide unit by can passing through of vertically moving on the workplace on the support key and support be slidingly connected vertically move dull and stereotyped and transversely movable by key with vertically move the flat board that laterally moves that workplace is slidingly connected on the flat board and form.
Described be used for loading force arm assembly that tested friction material test specimen installs and fixes be connected in by rotation axis be installed on front vertical plate and the back vertical plate, parallel with the main axis of spindle drive systems and and the relative support of main axis of spindle drive systems on the right-hand member of the contour back shaft of workplace, and front vertical plate and back vertical plate are packed on the transversely movable horizontal mobile flat board; The loading force arm assembly is the hole that is processed with the rectangular recess that is used to install test specimen location and installation piece, the hole that cooperates with locating shaft and mounting spring and spring compression screw by an end, and the other end becomes fork-shaped and be processed with the loading arm of force of the through hole that matches with rotation axis, rotation axis, test specimen location and installation piece, locating shaft, spring and spring compression screw to form; And rotation axis one end is processed with screw thread, and rotation axis, bearing, locating sleeve are used nut screwing clamping after being installed in the hole of back shaft end.
Described pressure control charger by be packed in the force transducer that brake cylinder in the circular hole that is used to install brake cylinder on the front vertical plate, the screw thread coaxial cable of piston rod front end by brake cylinder connect, the pressure bearing head that is threadedly connected to the force transducer other end is formed with the hydraulic system that is connected with pipeline.
Described friction force or moment of friction measurement mechanism laterally move dull and stereotyped go up and force transducer that adjustable pressure bearing head is equipped with in upper ends under the dynamometer link two ends is formed by being sleeved on the dynamometer link on the back shaft and being packed in of connecting with key.
The beneficial effects of the utility model are:
1) the utility model provides a kind of and is suitable for utilizing the sample form to carry out the testing machine that the friction material friction and wear behavior detects, this testing machine has overcome in the past, and the little sample testing machine does not have additional inertial, poor, the function singleness of test condition simulation, shortcomings such as range of application is little, have advantages such as inertia bench testing machine simulation is good, multiple functional, range of application is big.Test efficiency greatly improves, and testing expenses also greatly reduce.
2) design concept employing of the present utility model is a similarity theory, how much scale down are the area of friction material sample and the ratio of actual disk type brake disc friction area, carry out kinematics and kinematic similarity on this basis and contract than having designed a kind of friction test machine for small sample contracting ratio table.The equipment appearance physical dimension greatly reduces, and equipment investment and testing expenses are far below the inertia bench testing machine.
3) friction and wear behavior that utilizes the utility model to carry out friction material detects, can consider of the influence of the factor of different automobile types and different operating modes to Properties of Friction Materials, can improve the accuracy of little sample testing and the confidence level of test figure, the comparability level of raising and inertia bench test figure is by the test findings of little sample testing prediction and reflection inertia bench.
4) the utility model is applicable to the new product development formulating in earlier stage and the intermediate mass monitoring of friction material production run.Especially can carry out full test to the friction and wear behavior of friction material according to the standard of inertia bench test and method, this is the characteristics that are different from present little sample testing machine.
Description of drawings
Below in conjunction with accompanying drawing the utility model is further described:
Fig. 1 is a kind of front view of friction test machine for small sample contracting ratio table;
Fig. 2 is a kind of vertical view of friction test machine for small sample contracting ratio table;
Fig. 3 is a kind of front view of friction test machine for small sample contracting ratio table spindle drive systems;
Fig. 4 is a kind of left view of friction test machine for small sample contracting ratio table spindle drive systems;
Fig. 5 is a kind of vertical view of friction test machine for small sample contracting ratio table spindle drive systems;
Fig. 6 is the front view of a kind of friction test machine for small sample contracting ratio table slide unit system;
Fig. 7 is the left view of a kind of friction test machine for small sample contracting ratio table slide unit system;
Fig. 8 is the vertical view of a kind of friction test machine for small sample contracting ratio table slide unit system;
Fig. 9 is the front view that a kind of friction test machine for small sample contracting ratio table loads the arm of force;
Figure 10 is the A-A cut-open view that a kind of friction test machine for small sample contracting ratio table loads the arm of force;
Figure 11 is the vertical view that a kind of friction test machine for small sample contracting ratio table loads the arm of force;
Fig. 12 is a kind of friction test machine for small sample contracting ratio table friction force or friction torque test schematic diagram;
Among the figure: 1. support, 2. flywheel guard, 3. spindle drive systems, 4. dedusting assembly, 5. blowing cooling unit, 6. protective cover, 7. slide unit system, 8. computer control system and electric control box, 9. pressure control charger, 10. axle sleeve flange, 11. flywheel groups, 12. drive motor, the little profile of tooth belt wheel 13. test the speed, 14. clamp nuts, 15. stop washers, 16. copper ring, 17. insulation sleeves, 18. axle sleeve flanges, 19. the heat-barrier material fixed head, 20. heat-barrier materials, 21. thermopairs, 22. friction brake disk, 23. cog belts, the 24. big profile of tooth belt wheels that test the speed, 25. end cap, 26. mounting brackets, 27. bearings, 28. axle sleeve, 29. rotation axiss, 30. photoelectric encoders, the axle 31. photoelectric encoder tests the speed, 32. brush fixed supports, 33. carbon brush fixed heads, 34. carbon brush, 40. vertically move flat board, and 41. laterally move flat board, 42. front vertical plate, 43. back shafts, 44. vertically move dull and stereotyped feather key, 45. installing plate, 46. force transducers, 47. pressure bearing heads, 48. back vertical plate, 49. scales, 50. pointers, 51. handwheel, 52. end cap, 53. bearings, 54. connect fixed head, 55. saturating lid, 56. adjust cover, 57. dynamometer links, 58. keys, 59. saturating lid, 60. bearing, 61. end caps, 62. loading force arm assemblies, 63. lock-screw, 64. lock-screw, 65. handwheels, 66. pressure bearing heads, 67. force transducer, 68. the brake cylinder piston rod, 69. brake cylinders, 70. laterally move dull and stereotyped feather key, 75. locating sleeve, 76. bearing, 77. rotation axiss, 78. load the arm of force, 79. locking jackscrew, 80. locating shaft, 81. spring compression screws, 82. springs, 83. test specimen location and installation piece, 84. tested friction material test specimens.
Embodiment
Consult Fig. 1 and Fig. 2, a kind of friction test machine for small sample contracting ratio table is to adopt one-piece construction, mainly is made up of box support 1, spindle drive systems 3, dedusting assembly 4, blowing cooling unit 5, slide unit system 7, computer control system and electric control box 8, pressure control charger 9.Box support 1 adopts section bar, steel plate to be welded according to the big I of production lot, can adopt also that the casting of first bulk-breaking is affixed then to assemble, no matter which kind of method of employing will guarantee that all it has enough rigidity and intensity, last workplace will pass through processing, and longitudinally processes a break-through keyway.The slide unit system 7 that at first will be used for determining tested friction material sample 84 and friction brake disk 22 relative positions is connected through key, both be installed on the last workplace of support 1 by vertically moving dull and stereotyped feather key 44, vertically moving in the slide unit system 7 dull and stereotyped 40 can vertically move on workplace on the support 1; Then, being used to of to having a style of one's own simulates different inertia and provides drive motor 12 bases of spindle drive systems 3 by wherein of the operating condition of test of different rotating speeds also to be fixed on the last workplace of support 1 with bolt, and the distance of the main axis of the spindle drive systems 3 after the installation last workplace of the horizontal relative support 1 of axis that moves the pressure bearing head 66 on the flat board 41 relative to the distance of the last workplace of support 1 with in being installed in slide unit system 7 is equal and two axial lines is parallel.Blowing cooling unit 5 and dedusting assembly 4 are fixed by bolts on the following workplace in the box support 1, blowing cooling unit 5 is made up of the blower fan and the cooling duct of adjustable speed, the blowing cooling duct passes from the last workplace of support 1, the discharge pipe of terminal be positioned at friction brake disk 22 directly over, air outlet tube mouth is vertically downward.On workplace on the support under the friction brake disk 22, have a rectangular opening, rectangular opening links to each other with the aspiration channel of following dedusting fan, makes buffings such as hot blast and fricative dust in time drain.Pressure control charger 9 is made up of hydraulic system and the hydraulic actuating mechanism that is connected with force transducer 67 and pressure bearing head 66 both brake cylinder 69, hydraulic system mainly is made up of pump, servo-valve, pressure-regulating valve and pipeline, they are installed in the control box, this control box places the rear side of support 1, connect by screw and support 1, with pipeline it is connected with brake cylinder 69 then, pressure control charger 9 is connected with complete machine to be finished.Again computer control system and electric control box 8 also are connected to support 1 rear side by screw, adjacent with pressure control charger 9, install a protective cover 6 additional in spindle drive systems 3 front portions at last, a kind of friction test machine for small sample contracting ratio table assembling is finished.
Consult Fig. 3, described spindle drive systems 3 is made up of the flywheel gear of friction brake disk 22, drive motor 12, temperature measuring equipment, rotation-speed measuring device and simulated inertia; What described drive motor 12 adopted is the double output shaft motor, at first stretch out axle head and load onto the axle sleeve flange 10 that is used to install flywheel by the key connection in drive motor 12 right sides, flywheel group 11 is sleeved on the axle sleeve flange 10, and carry out fixedly connected with screw, for preventing coming off of axle sleeve flange 10 and flywheel group 11, in axial end back-up ring and screw retention, for safety adds a flywheel guard 2 again, cover on the flywheel group 11, be screwed during assembling on support 1.
Consult Fig. 3 to Fig. 5, described temperature measuring equipment includes to be installed on the drive motor 12 left side projecting shafts and connects axle sleeve flange 18 suit and be fixed with friction brake disk 22 at big end by key, begin to be sleeved on successively heat-barrier material 20 on axle sleeve flange 18 outside surfaces from big end, heat-barrier material fixed head 19, insulation sleeve 17, copper ring 16, stop washer 15, clamp nut 14, little profile of tooth belt wheel 13 tests the speed, wherein: test is to be contained on the left end face of axle sleeve flange 18 by screw with friction brake disk 22, for preventing that friction brake disk 22 and axle sleeve flange 18 from coming off from axle, be fixed with back-up ring and screw in axial end, heat-barrier material 20 is fixedlyed connected with friction brake disk 22 right sides by screw with heat-barrier material fixed head 19, test the speed little profile of tooth belt wheel 13 also by screw retention on the right side of axle sleeve flange 18.Locate along axial processing one small through hole of friction brake disk 22 in the friction radius of friction brake disk 22 end faces (according to vehicle and contract calculate) than ratio, radially process a threaded hole at friction brake disk 22 outer round surface, and two holes are communicated, the thermopair detecting head is inserted in the axial aperture at friction brake disk 22 friction radius places, make the thermopair detecting head apart from about friction brake disk 22 friction surfaces 0.5~1mm, adorn a screw in friction brake disk 22 radial screw bore, push down the thermopair detecting head and make it to maintain static.Square molded lines groove on the outside surface of the small through hole of the other end of thermopair by processing on heat-barrier material 20 and the heat-barrier material fixed head 19, axle sleeve flange 18 is drawn with the welding of copper ring 16 inner ring surfaces fixing, copper ring 16 outer ring surfaces slide with carbon brush 34 on being fixed on carbon brush fixed head 33 and reliably contact, and the temperature signal of assurance thermocouple assay reliably transmits.The carbon brush fixed head 33 that carbon brush 34 is housed be by screw retention on fixed support 32, fixed support 32 by screw retention on motor case left end top.
Consult Fig. 5, the described measurement mechanism that is used to measure the speed of mainshaft is the shell that is fixed on drive motor 12 by mounting bracket 26.At first rotation axis 29 is packed in the axle sleeve 28 with two bearings 27, with screw itself and end cap 25 are packed in the right left both sides that are fixed on the mounting bracket 26 on drive motor 12 shells then, the big profile of tooth belt wheel 24 that tests the speed is contained in the left end of rotation axis 29 by the key adapter sleeve, and fixed in the left side of rotation axis 29 with back-up ring and screw, with slip-off preventing, photoelectric encoder 30 is screwed at axle sleeve 28 right-hand members, photoelectric encoder axle 31 the left end that tests the speed links to each other with rotation axis 29 right-hand members by screw thread, and the big profile of tooth belt wheel 24 that tests the speed is with the little profile of tooth belt wheel 13 on the spindle drive systems 3 by cog belt 23 and is connected.
Consult Fig. 6 to Fig. 8, described slide unit system 7 by slide unit, the measurement mechanism that is used for loading force arm assembly 62, pressure control charger 9, friction force or moment of friction that tested friction material test specimen 84 installs and fixes forms; Described slide unit is made up of the parts such as flat board 40 and transversely movable horizontal mobile dull and stereotyped 41 that vertically move that can vertically move on support.Vertically moving of slide unit dull and stereotyped 40 is bases of whole slide unit system.On workplace on the support 1, longitudinally process a guiding rectangle keyway with the break-through of spindle drive systems 3 axis normal, one feather key 44 is housed in the groove, vertically moving dull and stereotyped 40 is a rectangular flat, the bottom promptly descends workplace longitudinally also to process the rectangle keyway of a break-through, cooperates with feather key 44.By the handwheel 65 of rotational fixation on support 1, whole slide unit system can vertically move along feather key 44.A pointer 50 is housed vertically moving on dull and stereotyped 40 left end face, be fixed on support 1 on scale 49 on the workplace cooperate, be used for showing the distance that slide unit vertically moves.Vertically moving on dull and stereotyped 40 on the workplace, the rectangle guiding keyway along laterally having with the spindle drive systems parallel axes is equipped with a feather key 70 in the groove.Laterally moving on dull and stereotyped 41 times workplaces, along laterally also processing rectangle guiding keyway, and cooperate with feather key 70,, make and laterally move dull and stereotyped 41 and can laterally move on the workplace vertically moving on dull and stereotyped 40 in the handwheel 51 that vertically moves on dull and stereotyped 40 by rotational fixation.The slide unit alliance determines that the back will vertically move dull and stereotyped 40 with four screws 63 and be fixed on the support 1, will laterally move flat board 41 with four screws 64 and be fixed on and vertically move on the flat board 40.
Consult Fig. 6, Fig. 9 and Figure 10, described be used for loading force arm assembly 62 that tested friction material test specimen installs and fixes be connected in by rotation axis 77 be installed on front vertical plate 42 and the back vertical plate 48, parallel with the main axis of spindle drive systems 3 and with the right-hand member of the contour back shaft 43 of the last workplace of the relative support 1 of main axis of spindle drive systems 3, and front vertical plate 42 and back vertical plate 48 are packed in and transversely movablely laterally move on dull and stereotyped 41; Loading force arm assembly 62 is to be processed with the rectangular recess that is used to install test specimen location and installation piece 83, to be processed with the hole that cooperates with locating shaft 80 and to be processed with mounting spring 82 and the hole of spring compression screw 81 by an end, and the other end becomes pronged shape and be processed with the loading arm of force 78 of the through hole that matches with rotation axis 77, rotation axis 77, bearing 76, locating sleeve 75, test specimen location and installation piece 83, tested friction material test specimen 84, locating shaft 80, spring 82 and spring compression screw 81 to form.Wherein: four locking jackscrews 79 that are used for trivial tight tested friction material test specimen 84 are arranged on the test specimen location and installation piece 83; Rotation axis 77 1 ends are processed with screw thread, and rotation axis 77, two bearings 76, locating sleeves 75 are used nut screwing clamping after being installed in the hole of back shaft 43 ends.
Consult Fig. 8 and Fig. 2, described pressure control charger 9 by be packed in the force transducer 67 that brake cylinder 69 in the circular hole that is used to install brake cylinder 69 on the front vertical plate 42, the screw thread coaxial cable of piston rod 68 front ends by brake cylinder 69 connect, the pressure bearing head 66 that is threadedly connected to force transducer 67 other ends is formed with the hydraulic system that is connected with pipeline.In fact the part of pressure control charger 9 places support 1 rear side, and is fixed with screw, with pipeline itself and the brake cylinder 69 that is packed on the front vertical plate 42 is coupled together then, and described pressure control charger 9 promptly installs.Wherein brake cylinder 69 is packed on the front vertical plate 42 with screw.
Consult Fig. 6, described friction force or moment of friction measurement mechanism laterally move on dull and stereotyped 41 and force transducer 46 that adjustable pressure bearing head 47 is equipped with in the upper end under dynamometer link 57 two ends is formed by being sleeved on the dynamometer link 57 on the back shaft 43 and being packed in of connecting with key 58.Dynamometer link 57 concrete installation site on back shaft 43 is: laterally moving dull and stereotyped 41 is a welding square structure spare, laterally moves on dull and stereotyped 41 and is welded with front vertical plate 42 and back vertical plate 48 respectively on the workplace, and connect with connecting fixed head 54.On front vertical plate 42 and back vertical plate 48, be processed with two circular holes that are on the same axis respectively, in the circular hole of back vertical plate 48, load onto bearing 53, end cap 52 successively and cover 55 thoroughly, and be screwed, then the left end of back shaft 43 is passed the circular hole on the front vertical plate 42 and load onto key 58 successively, cover 59 thoroughly, dynamometer link 57 and adjust cover 56 and pack at last in the hole of bearing 53, next from the right-hand member of back shaft 43 pack into bearing 60 and end cap 61, will cover 59 thoroughly with screw and be connected with end cap 61 and also bearing 60 to be fixed in the hole of front vertical plate 42 simultaneously.Assembling back shaft 43 axle center, back and friction brake disk 22 axle center are promptly contour with the main axis of spindle drive systems 3.Be used for the loading force arm assembly 62 that tested friction material test specimen 84 installs and fixes and be connected in the hole of back shaft 43 right-hand members described at last by rotation axis 77.Be packed in and laterally move on dull and stereotyped 41 and force transducer (46) that adjustable pressure bearing head 47 is equipped with in the upper end under dynamometer link 57 two ends is realized by installing plate 45 and screw.
The spindle drive systems 3 that the utility model adopted is the operating condition of test that are used to simulate different inertia and different rotating speeds.Spindle drive systems has a style of one's own, adopt double output shaft drive motor 12 as power source, test is loaded on the left end of drive motor 12 left side output shafts with friction brake disk 22, in the axial aperture of friction brake disk 22, thermopair is housed, is used for measuring the temperature on friction process friction brake disk 22 surfaces.The right-hand member of drive motor 12 right side output shafts is equipped with flywheel group 11, is used to test inertia simulation.Drive motor 12 belongs to buncher (comprising ac variable frequency speed regulation, DC speed regulation and electromagnetic speed-adjusting) again, realizes the multiple rotating speed of main shaft.The utility model has dual mode on inertia simulation, adopt the mechanical analogue inertia of a plurality of mechanical flywheel array modes, can adopt electric analogy technical modelling mechanical inertia in addition, promptly utilize motor constantly to export the electric analogy machinery inertia mode that energy substitutes the flywheel store kinetic energy.So electric analogy machinery inertia mode is also within protection domain of the present utility model.
Slide unit system 7 is the clampings that are used for the determining of tested friction material test specimen 84 and friction brake disk 22 relative positions, tested friction material test specimen 84.Can make slide unit realize laterally with longitudinally moving by rotation hand wheel 51,65, vertically move distance and show by scale 49 and pointer 50.Various force transducers are installed in the slide unit system 7, are used for the measurement of damping force, friction force (or moment of friction).
The pressure control charger is to adopt servocontrol, realizes the automatic control to damping force.Promptly by feedback, realize that the suffered damping force in tested friction material test specimen 84 surfaces keeps constant, also can realize the damping force servo-actuated, the friction force (or moment of friction) that tested friction material test specimen 84 working surfaces are produced in friction process keeps constant.Thereby simulate different damped conditions.
Temperature control system is measurement and the control that is used for friction brake disk 22 skin-friction temperatures.Utilization is contained in the thermopair in friction brake disk 22 axial aperture, measure the temperature of friction brake disk 22 friction surfaces in the friction process, adopt the adjustable speed fan simulation air-cooled pattern similar to actual condition, according to the cooling wind speed and the friction temperature of testing requirements, realize the cooling air quantity size by computer controlled automatic adjustable speed fan rotating speed.
Computer control system and electric control box 8 are the control that is used for electric analogy machinery inertia, test routine operation and control, and data acquisition, processing and storage, test figure and trial curve show and print.
A kind of friction test machine for small sample contracting ratio table method of operating:
1) at first tested friction material test specimen 84 is installed in the test specimen location and installation piece 83, and with locking jackscrew 79 fixed, the location and installation piece 83 that test specimen will be housed then is loaded in the rectangular recess that loads the arm of force 78, make it to contact well with locating shaft 80, and utilize spring 82 and spring compression screw 81 to make that test specimen location and installation piece 83 is unlikely to be deviate from rectangular recess, can make minor rotation around locating shaft 80 again simultaneously.Adjust pressure bearing head 47 front and back positions of force transducer 46 front ends, the first end of pressure-bearing is a screw thread, connects by screw thread and force transducer, by adjusting the reach that screws in force transducer 46, changes the pressure bearing head front and back position, makes dynamometer link 57 keep horizontality.
2) the tested friction material test specimen 84 of rectangle will satisfy testing requirements with the relative position of friction brake disk.Vertically move handwheel 65 by rotation and adjust the slide unit lengthwise position, can determine according to the position of pointer 50 on scale 49; Adjust the slide unit lateral attitudes by rotating horizontal mobile handwheel 51, make between the friction working surface of tested friction material test specimen 84 friction working surfaces and friction brake disk 22 apart from satisfying testing requirements, for about 0.5mm.After tested friction material test specimen 84 is determined with respect to the position of friction brake disk 22, will vertically move flat board 40 and laterally mobile dull and stereotyped 41 with four screws 63 and four screws 64 and lock.
3) according to testing requirements apolegamy flywheel or enable electric analog system, and in test routine, test parameters such as pressure, moment, speed and control model are provided with and adjust, promptly finished the preliminary work before the test.
4) start speed governing drive motor 12, drive spindle drive systems 3 rotations, make friction brake disk 22 rotations that are installed on the spindle drive systems 3.Starting pressure control loaded device 9, the pressure of fluid is controlled by pressure-regulating valve, hydraulic oil acts on the rodless cavity of brake cylinder 69 through servo-valve, the force transducer 67 that promotes piston rod 68 and be attached thereto, pressure bearing head 66 reaches, promote to load the arm of force 78 moving axis 77 that rotates and produce minor rotation, make and be loaded on the friction brake disk 22 work friction surfaces that the tested friction material test specimen 84 that loads in the arm of force 78 rectangular recess is pressed towards rotation, the test specimen location and installation piece 83 that tested friction material test specimen 84 is housed is made minor rotation around locating shaft 80, make tested friction material test specimen 84 surfaces be tending towards parallel automatically with the friction brake disk working surface and contact, increase with damping force, make tested friction material test specimen 84 closely contact and produce friction, enter trystate with friction brake disk 22 large tracts of land.
The rotating speed of friction brake disk 22 is measured by photoelectric encoder 30 in the process of the test; Temperature is measured by the thermopair 21 that is loaded on the friction brake disk 22, thermopair 21 places the friction catch radius of friction brake disk 22 to be according to vehicle and to contract and calculate than ratio, the temperature of friction brake disk 22 is by thermocouple measurement, carry out data processing and conversion by computer control system, and on computer screen, shown.Computer control system can be judged the whether Pass Test requirement of temperature of friction brake disk automatically, does not satisfy testing requirements as temperature is too high, starts 5 pairs of friction brake disks of blowing cooling unit automatically and gives and cooling, makes it the Pass Test requirement.The cooling air quantity adjustable size joint of this cooling system; The size of the damping force that brake cylinder 69 produces has force transducer 67 to measure; The size of the friction force (moment) that friction catch produces is measured by force transducer 46, its test philosophy is consulted Figure 12, friction brake disk rotates by direction as shown with rotation speed n, brake cylinder produce the damping force of horizontal direction be F, tested friction material test specimen 84 is f with friction brake disk 22 mutual fricative drag friction power, braking moment is M, and the power that force transducer 46 is measured is F
f, there is following mathematical relation between them:
Drag friction power f=F
fL
1/ L
2
Braking moment M=fR=F
fRL
1/ L
2
Friction material coefficientoffriction=f/F
A kind of friction test machine for small sample contracting ratio table is according to testing requirements, can realize the test of velocity correlation (friction brake disk 22 different rotating speeds) friction catch, the test of pressure correlation (under the different brake pressures) friction catch, the constant force square (adjust automatically with the variation of friction factor by damping force, make the friction force of output or moment of friction keep constant) the friction catch test, temperature correlation (under the differentiated friction temperature) friction catch test etc.
A kind of pressure control charger 9 principle of work of friction test machine for small sample contracting ratio table:
After tested friction material test specimen 84 installs, start automatic test program, speed governing drive motor 12 drives spindle drive systems 3 rotations.Behind the rotating speed that reaches test determination (setting), the pressure control charger starts automatically, the pressure of fluid is controlled by pressure-regulating valve, hydraulic oil acts on the rodless cavity of brake cylinder 69 through servo-valve, the force transducer 67 that promotes piston rod 68 and be attached thereto, pressure bearing head 66 reaches, promote to load the arm of force 78 moving axis 77 that rotates and produce minor rotation, make and be loaded on the friction brake disk 22 work friction surfaces that the tested friction material test specimen 84 that loads in the arm of force rectangular recess is pressed towards rotation, make tested friction material test specimen 84 contact and produce friction, enter trystate with friction brake disk 22.Under the constant pressure test model, require damping force F constant, servo-valve can be adjusted its output oil liquid pressure automatically according to the measured value size of force transducer 67, makes damping force F keep constant.Under constant force square test model, require braking moment M constant, servo-valve can be adjusted its output oil liquid pressure automatically according to the measured value size of force transducer 46, makes braking moment M keep constant.
Various test parameterss in the process of the test all can measured and calculating as brake pressure, damping force, rotating speed, temperature, braking moment, braking time, braking deceleration, braking distance.Its data are stored, and can show on computer screen.
After braking procedure finishes, fluid acts on the rod chamber of brake cylinder 69 through servo-valve, promotion piston rod 68 and the force transducer 67 that is attached thereto, pressure bearing head 66 are return, make brake cylinder retreat to original position, because tested friction material test specimen 84 and friction brake disk 22 surface in contacts exist small rough and uneven in surface, 22 pairs of tested friction material test specimens 84 of the friction brake disk of rotation produce one along the opposite thrust component intended of loading direction, make to load the arm of force 78 moving axis 77 that rotates and produce minor rotation, tested friction material test specimen 84 is disengaged with friction brake disk 22.For braking is next time prepared.