SU1486885A1 - Method of determining contact rigidity of friction pair - Google Patents

Description

The invention relates to the determination of the rigidity of the movable contact

friction pairs. The aim of the invention is to increase the reliability of the results of determining the stiffness of the contact. Counterpiece 12 is moved relative to · sample 11 and is loaded. · During the determination of stiffness, the mass of the disks 5 and their moment of inertia are changed, variable components of the forces of frictional interaction of the surfaces of counterpiece 18 and sample 11 are recorded in the plane of the contact area and in the plane normal to the contact area. The eigenfrequencies of the friction pair in the indicated planes and the contact stiffness of the friction pair are determined in the densities of the vibration spectra. 3 il.

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The invention relates to the field of engineering and can be used; in particular, to determine the rigidity of the moving contact of a friction pair.

The aim of the invention is to increase the reliability of the results of determining the rigidity of the movable contact

FIG. 1 shows a device for implementing a method for determining the stiffness of a contact of a friction pair; FIGS. 2 and 3 show the spectra of oscillations of the forces of frictional interaction of a friction pair in a plane perpendicular to the contact zone and the plane of the contact zone.

The device contains a drive 1 and an electromagnetic clutch 2, resulting in rotation of the flywheel 3 with the shaft 4. On the flywheel 3, removable discs 5 are installed that perform the functions of a loading unit. Magnetic, supports 6 and 7 fix the shaft 4 in the longitudinal direction. The support 6 is fixed in the cover

8, and support 7 - in a massive holder

9, enshrined on base 1.0. The test sample 11 is mounted on the holder 9 ,. counterpiece Ί 2 - on the flywheel 3, Magnetoisolating pads 13 connect the flywheel 3 to the shaft 4 and the magnetic supports 6 and 7, thus eliminating the influence of the mechanical system parameters on the friction process of the friction pair.

The method for determining contact stiffness par: friction is as follows.

Using the actuator 1 and the electromagnetic clutch, the contra-sample 12 is moved relative to the sample 11, the friction pair is loaded using interchangeable discs 5, providing a predetermined contact pressure on the contact of the counter-sampler 12 and the specimen 11, the mass of the discs 5 and their moment of inertia are changed drive voltage drop of '1 and variable components of the forces of frictional interaction of surfaces in the plane of the contact zone and in the plane perpendicular to this zone (using, for example, a piezoelectric sensor and an oscilloscope with memory). Then, in the densities of the vibration spectra, the frequencies corresponding to the natural oscillations of the friction pair in these planes are determined; The stiffnesses in these planes are determined by the formulas:

where _{ί θΜ} , - frequency of

oscillations of the pair. friction in the normal to the contact zone plane and in the plane of the contact zone ·, '

TP and I - the mass and moment of inertia of the loading unit.

PRI me R. The stiffness of the rolling contact of the friction pair was determined: composition of FC 24A-St 45. Specific pressure P = 4 MPa, sliding speed V = 0.05 m / s, mass w = 3.5 kg, inertia moment I * = 2.4 kgm ^g . FIG.

Figures 2 and 3 show the vibration spectra in the normal plane and in the plane of the contact zone, respectively. Similar vibration spectra were obtained at .Т ₂ = 3.4 kgm ² (not shown). The value _{ί οΝ} = = ζ ' _Ν = 600 Hz, where G _{ohm is} obtained from the vibration spectrum at 1 ^ = 3.4 kgm ² . Stiffness in the normal plane С _max = Р · ш ⁼

= 1.26'10 ⁶ N / m. The value ίθ ~ = 500 Hz with I, = 2.5 kgm ² and £ * a. = 700 Hz at 1 ₄ = 3.4 kgm ² . Respectively stiffness C l. = 0.6 · 10 ^ η / μ and Сл. = 1.67 * x10 ^b n / m.

Claims (1)

Claim I y The method of determining the stiffness of the contact of a friction pair, which consists in using a loading unit to exert a load on the contact of the rough surfaces of the friction pair and record the result of this impact, which determines the contact stiffness of the friction pair, characterized in that, in order to increase the reliability of the stiffness determination results rolling contact _} in the process of exposure to the load change the mass and the moment of inertia of the loading node, as a result of the impact, the variable components are recorded The forces of frictional interaction of surfaces in the plane of the contact zone and in the plane normal to the contact zone and the density of vibration spectra, which determine the frequencies of 7. l. and _RL .. corresponding sobον and and fluctuations of friction in these planes, and rigidity (’.? and 1486885 C _{n is} determined respectively in a flat- (- p bones of the contact zone and in normal to the contact zone of the plane by the formulas a) ^five e N = X π, with _r = -I., where t and I are, respectively, the mass and moment of inertia of the loading unit. yo 80 60 Lb go -Θ-4-3- 1¼ I> and? // 0.2 OL 0.6 08 10 12] L / Fig · 2 ABOUT 12 1L Lhz) Fig-3