Device for determining molecular component of friction coefficient

FIELD: investigating or analyzing materials.

SUBSTANCE: device comprises housing, mechanism for loading, specimen holders that are provided with parallel bearing planes and mounted one opposite to the other. One of the holders cooperates with the loading mechanism. The mandrel provided with the spherical indenter is interposed between the specimen holders. The device has the mechanism for rotation of the indenter around its axis and unit for measuring the applied moment. The mechanism for rotation of the indenter is made of the lever secured to the mandrel, segment secured to the lever, and flexible link that embraces the segment and undergoes the load.

EFFECT: expanded functional capabilities.

1 dwg

 

The invention relates to the field of test engineering, in particular to devices for determination of the friction coefficients and their components.

The known device [1] to determine the molecular component of the friction coefficient, i.e. the adhesive strength of relationships of the investigated materials for cutting, comprising a housing, a loading mechanism, set against each other with the possibility of rapprochement between the specimen holder with parallel reference planes, one of which communicates with the loading mechanism located between the holders of the mandrel mounted therein a spherical indenter, the rotation mechanism of the indenter around its axis and a device for measuring applied to the indenter torque.

During the test, the indenter is pressed into the sample surface flat samples and it is applied torque, providing rotation of the indenter in the plane parallel to the planes of the samples. The molecular component of the friction coefficient is determined by the magnitude of the friction torque required for rotation of the indenter.

As in the known device is implemented scheme friction pivoting, in the contact zone of the velocity distribution is uneven, they vary from 0 to Vmax. In addition, in this case, it is necessary to measure the impact on flat samples, as in the calculation of the second formula is the radius of the print. This introduces additional error in the determination of the molecular component of the coefficient of friction under conditions of sliding friction.

The closest technical solution, selected as a prototype, is a device for determining molecular component under conditions of sliding friction [2], in which the rotation mechanism of the indenter is made in the form set can be rotated in the plane perpendicular reference planes holders, and rigidly attached to the mandrel arm fixedly mounted on it segment, an arc described from the center of the indenter, and covering the segment along the arc of a flexible connection, which affects the load, such as suspended load.

The disadvantage of the described technical solutions adopted for the prototype, is the impossibility of taking into account the influence of the magnetic flux and electric current at the molecular component of the friction coefficient.

The technical result of the invention is to enhance the functionality of the device by taking into account the effect on the molecular component of the friction coefficient of external factors, what are the magnetic flux and electric current.

The technical result is achieved in that the device for determining the molecular component of the friction coefficient consists of a casing, mechanism of loading, to ascertain the data against each other with the possibility of convergence of sample holders with parallel reference planes, one of which communicates with the loading mechanism, located between the holders of the mandrel mounted therein a spherical indenter, the rotation mechanism of the indenter around its axis and measurement devices applied to the indenter torque. The device is equipped with a magnetic core located therein an electromagnetic coil, which forms together with the holders of the samples, samples and spherical indenter common magnetic circuit, and a current source connected to the current-carrying wires to the samples.

The invention is illustrated in the drawing.

The device includes a housing 1, a loading mechanism 2, the specimen holder 3 with the reference plane And on which are mounted the samples with 4 flat and parallel to each other of the investigated surfaces, the mandrel 5 is fixed inside a spherical indenter 6 mechanism 7 of rotation of the indenter around its axis, made in the form of a lever, one end of which is rigidly fixed to the mandrel 5, and the other end provided with segment 8.

The lever by means of a flexible connection 9, covering the segment of the arc, impact load, which can be used in spring or suspended load 10. Arc segment 8 is described from the center of the indenter, which ensures the consistency of the shoulder of application of the load to the lever in the process of evapourate, consequently, consistency applied to the indenter torque.

The time is recorded by a measuring device (not shown). To create a zone of contact with the external influences, the instrument is provided with a magnetic core 12 is installed on a us electromagnetic coil 13, and a current source 14, which has the possibility, by means of current-carrying wires 15 connect to the test samples 4. To create the magnetic flux mainly passes through the contact zone, the lower holder 3 is isolated from the casing 1 of insulating gasket 11 and the magnetic core 12 is tightly in contact with the holder 3, forming a common path for passing magnetic flux through the sample 4.

The device operates as follows.

Two plane-parallel sample 4 are fixed in the holders 3. Is established between the mandrel with the indenter 6. By means of the loading mechanism 2 to the samples of the applied compressive load. The exposure time of the samples under load should be sufficient to complete plastic deformation in the zone of contact of the indenter with the samples and must meet the standard Brinell test. To the electromagnetic coil 13 is supplied with AC or DC voltage, thereby a magnetic flux. Turns on the current source 14 and a current is applied to the sample 4. Thus, at the contact zone of the Indus the Torah 6 samples 4 are external disturbances.

The indenter applied torque Mkrrequired for a uniform rotate it in the plane perpendicular reference planes holders, i.e. in the plane compressive load samples n measured values of moment Mkrand loads of N determine the molecular component of the friction coefficient.

Technical and economic efficiency of the invention in comparison with the prototype is that the device for determining the molecular component of friction is equipped with a magnetic core located therein an electromagnetic coil, and a current source connected to the current-carrying wires to the samples. This allows the contact area of the external disturbing factors in the form of magnetic flux and electric current and to consider their influence on the molecular component of the friction coefficient, which expands the functionality of the device.

Literature

1. Kragelskii IV and other calculation is based on friction and wear. M.: Mashinostroenie, 1977. - 526 S. S.

2. AS the USSR №348927, published. 23.08.72, bull. No. 25.

Device for determining the molecular component of the coefficient of friction, comprising a housing, a loading mechanism, set against each other with the possibility of rapprochement between the specimen holder with parallel reference planes, one of which is communicates with the loading mechanism, located between the holders of the mandrel mounted therein a spherical indenter, the rotation mechanism of the indenter around its axis and a device for measuring applied to the indenter torque, and the rotation mechanism of the indenter is made in the form rigidly attached to the mandrel arm, which can rotate in the plane perpendicular to the reference planes of the samples, permanently installed on the lever segment, an arc described from the center of the indenter, and covering the segment along the arc of a flexible connection, which affects the load, characterized in that the device is equipped with the magnetic core located therein an electromagnetic coil, which forms together with the specimen holder, samples and spherical indenter common magnetic circuit, and a current source connected to the current-carrying wires to the samples.



 

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