RU211643U1 - Device for providing simulation of real loading cycles of the resonant stand - Google Patents

Abstract

The utility model relates to the field of mechanical engineering and can be used for testing materials for fatigue in assessing the endurance limit of full-scale crankshafts and their segments. A device for simulating real loading cycles of a resonant stand consists of a loading system in a horizontal plane, including an electric motor with a flexible drive and an eccentric assembly for bending loading, a control and monitoring unit, a crankshaft under test, a mounting mechanism, spring supports, leading and driven resonant masses . An additional loading mechanism was introduced into the design of the stand, consisting of an electric motor installed motionless relative to the driven resonant mass, the output shaft of which is connected to a swivel coupling that transmits torque to a sliding splined pair, presented in the form of a splined shaft and a bushing rigidly connected to an eccentric assembly for torsion loading located in the bearing units of the driven resonant mass, which provides torsion of the tested crankshaft. The utility model makes it possible to expand the range of application of the device for testing crankshafts for fatigue by improving the design of the device with a maximum approximation to the real operating modes of shafts in circular bending and at the same time load it with a variable symmetrical bending cycle in the crank plane with a constant stress amplitude and introduce vibration excitation at which the shaft experiencing torsion. 1 ill.

Description

The utility model relates to the field of mechanical engineering and can be used for testing materials for fatigue in assessing the endurance limit of full-scale crankshafts and their segments.

Known mechanism for loading the stand for fatigue torsion testing. Bench for testing crankshafts for torsion fatigue strength, containing a loading device, an element of the crankshaft, one end of which is rigidly attached through the power take-off flange to a vertical fixed rack of the loading device, characterized in that it uses a roller pressed with an interference fit on the free end of the shaft , having the ability to freely ride on the base plate, which is rigidly attached to the table of the loading device, and the surface of the base plate mated with the roller repeats the shape of the supporting surface of the roller, while a lever is attached to the roller, to which, through a spherical stop attached to the loading servo-hydraulic device, eccentric load from the piston of a servo-hydraulic loading device, under the influence of which a roller rigidly connected to the lever can perform a rocking motion around an axis coinciding with the longitudinal axis of the crankshaft and transmit torque to the crankshaft element (RU 2570333, IPC G01M 15/02 publ. 12/10/2015).

The disadvantage of the known technical solution is the limited functional test modes (torsion test).

Also known is the design of the loading mechanism, presented in the form of a crank mechanism. The stand for testing the fatigue strength of the crankshaft of the internal combustion engine contains a power frame with a plate for placing on it the supports of the main bearings of the crankshaft and a loading element. In order to increase the reliability of tests, the stand is additionally equipped with a cantilever beam with a groove and a pin placed in it, adjusting shims, a lubrication system and an adjusting plate placed horizontally inside the power frame and provided with grooves, and the loading element is made in the form of a crank-and-rod loading mechanism, and the plate to accommodate the supports of the main bearings of the crankshaft, it is installed vertically and rigidly connected to the adjusting plate, on which, with the help of bolts passing through its grooves, the loading mechanism is fixed, the cantilever beam is rigidly connected with the end of the main bearing neck of the shaft, and with a pin - with the connecting rod of the loading mechanism, adjusting gaskets are placed between the adjusting plate and the loading mechanism, and the lubrication system is connected to the crank bearings of the loading mechanism (SU 1603209 IPC G01M 13/00 publ. 10/30/1990).

The disadvantage of the known technical solution is the lack of the possibility of accelerating fatigue tests under bending loading conditions.

For the prototype, the loading device of the resonant stand was chosen, which includes: an electric motor, a flexible drive and an eccentric unit of the experimental setup. The experimental setup refers to test bench equipment and is used for fatigue studies of crankshafts in a pure bending cycle. The design of the experimental setup consists of resonant masses, an electric motor, a flexible drive, an eccentric assembly, spring supports, a mounting mechanism and a crankshaft under test (B.P. Davydov “Development and study of methods for assessing and increasing the fatigue life of remanufactured parts: on the example of crankshafts for automobile and tractor engines” (access mode: https://search.rsl.ru/ru/record/01008467911 accessed: 03/31/2022).

The disadvantage of the existing loading device is the limited functional test modes (bending tests), which does not allow reproducing the operating conditions of the tested crankshaft, because during operation, the shaft is subjected to bending and torsional loads.

The technical result consists in expanding the range of application of the device for testing crankshafts for fatigue by improving the design of the device with a maximum approximation to the actual operating modes of the shafts in circular bending.

The technical result is achieved by the fact that the device for providing simulation of real loading cycles of the resonant stand consists of a loading system in a horizontal plane, including a flexible drive electric motor and an eccentric assembly for bending loading, a control and monitoring unit, a crankshaft under test, a mounting mechanism, spring supports , leading and driven resonant masses. An additional loading mechanism was introduced into the design of the stand, consisting of an electric motor installed motionless relative to the driven resonant mass, the output shaft of which is connected to a swivel coupling that transmits torque to a sliding splined pair, presented in the form of a splined shaft and a bushing rigidly connected to an eccentric assembly for torsion loading located in the bearing units of the driven resonant mass, which provides torsion of the tested crankshaft.

In FIG. 1 shows a diagram of a device for simulating real loading cycles of a resonant stand.

A device for simulating real loading cycles of a resonant stand (Fig. 1) consists of a loading system in a horizontal plane, including an electric motor 1 with a flexible drive 2 and an eccentric assembly for bending loading 3, a control and monitoring unit 4, a crankshaft under test 5, a mechanism mounting 6, spring supports 7, leading 8 and driven 9 resonant masses. An additional loading mechanism was introduced into the design of the stand, consisting of an electric motor 10 installed motionless relative to the driven resonant mass 9, the output shaft of which is connected to a swivel coupling 11, which transmits torque to a sliding splined pair, presented in the form of a splined shaft 12 and a bushing 13, with the possibility of compensation angular movements during testing for variable bending, and a sliding spline pair compensates for axial movements. The sleeve 13 is rigidly fixed with an eccentric assembly for torsion loading 14, placed in the bearing assemblies of the driven resonant mass 9, which provides torsion of the tested shaft.

The device works as follows. Leading 8 and driven 9 resonant masses with the test crankshaft 5 fixed in the mounting mechanism 6, due to the compliance of spring supports 7, which do not deprive the resonant masses 8, 9 of all degrees of freedom, form an oscillatory system. The electric motor 1 through the flexible drive 2 rotates the eccentric assembly for loading on the bend 3 and excites vibrations of resonant masses 8, 9 with the tested crankshaft 5, in which the tested crankshaft 5 is bent in a horizontal plane. In turn, to simulate real loading cycles, the electric motor 10, through the drive mechanism (consisting of: clutch 11, splined shaft 12 and bushing 13), transmits rotation to the eccentric assembly 14, additionally exciting vibrations, in which the tested crankshaft 5 is twisted. The control and monitoring unit 4 synchronizes the operation of two electric motors 1 and 10.

Compared with the known solution, the device makes it possible to expand the range of application of the device for testing crankshafts for fatigue by improving the design of the device with a maximum approximation to the real operating modes of the shafts in circular bending and at the same time load it with a variable symmetrical bending cycle in the crank plane with a constant voltage amplitude and introduce oscillation excitation at which the shaft experiences torsion.

Claims (1)

A device for providing simulation of real loading cycles of a resonant stand, consisting of a loading system in a horizontal plane, including an electric motor with a flexible drive and an eccentric assembly for bending loading, a control and monitoring unit, a crankshaft under test, a mounting mechanism, spring bearings, leading and driven resonant masses, characterized in that an additional loading mechanism has been introduced into the design of the stand, consisting of an electric motor installed motionless relative to the driven resonant mass, the output shaft of which is connected to a swivel coupling that transmits torque to a sliding splined pair, presented in the form of a splined shaft and a bushing rigidly connected with an eccentric unit for torsion loading, located in the bearing units of the driven resonant mass, which provides torsion of the tested crankshaft.

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