RU2755510C1 - Stand for testing torsion bars - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to installations for testing torsion bars. The stand contains a monitoring and control system, a bed, replaceable active and passive grippers, a loading mechanism connected to an active gripper. The active gripper has a means of locking the torsion bar in a twisted position in the form of an exhaust spring-loaded retainer. The passive gripper is mounted on a movable rack that can be moved along the body. The movable stand has a limiter for the movement of the removable passive gripper.

EFFECT: possibility to disable the power drive when testing torsion bars for a long subsidence is achieved.

1 cl, 2 dwg

Description

The invention relates to testing devices, namely to installations for testing torsion bars for deflection or settling, and is intended for testing torsion shafts of various lengths with different geometry and head sizes.

In the production of some spring products, according to the design documentation, it is envisaged to test them by means of non-volition, the duration of which can reach from several minutes to a day or more. It is recommended to carry out the usual refusal in GOST 53827-2010 "Cylindrical screw springs, torsion bars, suspension stabilizers" at least three times. At the same time, it is said about the need to use stands for testing springs (GOST 51585) or cardan shafts (GOST 52439) when testing torsion bars. Torsion test specimens are usually in the form of a shaft or tube. Therefore, such a stand usually has grips for samples and a means for twisting them.

At the same time, these stands must be equipped with force-measuring devices and sensors, which make it possible to record the applied torque and angle of twisting. At the same time, the time, magnitude and direction during testing may differ depending on the requirements set in the design documentation. A number of serially produced products for torsion testing are most often performed programmable with appropriate monitoring and control systems (http://www.ndt-td.ru/katalog/mashini-dlya-ispitaniya-pruzhin/mashina-dlya-ispitaniya-torsionnih- pruzhin-na-kruchenie-t-01.html, found on the Internet 01/25/2021).

Among the solutions described in more detail, one can note, for example, a torsion test setup (US Pat. No. 165460, G01N 3/22, dated 04.22.2015). Here, the monitoring and control system has movement registration, rotation drive regulation and torque measurement. In this case, the latter is made in the form of a beam force measuring device. At the same time, the installation is equipped with universal fixation devices, which allow fixing test objects of various shapes and sizes, both from the side of active and passive grips, through the system of calibration cracks, to perform a continuous test process.

Known stand for testing torsion shafts for torsional fatigue containing a base on which are mounted means for placing grips, means for twisting (AS No. 1656370, G01M13 / 00, from 22.03.1989). Here, interchangeable splined bushings for different diameters of torsion bars are used as grippers. Worm-type means are used to twist two torsion bars at the same time. Initially, the torsion bars are statically twisted in opposite directions, leading to their equilibrium state, to which an additional dynamic load is subsequently imposed in a given range of angles. In the description of the proposed stand, there is no mention of the force and angle sensors used in the mechanical scheme of the stand, which leads to inconsistency with the requirements of the above regulatory documents.

Known technical solution in the form of an installation for testing cylindrical specimens for torsion, containing an adjustable rotation drive, kinematically connected with two active grips, two passive grips, fixed coaxially with active grips on the torsion bar of the torque meter (US Pat. RU # 2379649, G01N 3/22 , dated 04/14/2008). Both passive grips are equipped with levers supported from opposite sides on the elastic element of the beam force meter, which performs the function of the said torque meter. In this case, samples of different diameters are tested to determine the resistance of materials to plastic and elastic shear deformation in accordance with the formulas given in the description. Here, as a rotation drive for a worm gear, it is proposed to use a lathe chuck, and its bed as a base for fixing the rack with test specimens manufactured in accordance with GOST 3565-80 “Metals. Torsion test method ".

A known stand for testing an elastic element containing a frame on which is mounted an active grip associated with a power drive, a passive grip, an indicator of the angle of twisting of the test sample (US Pat. RU No. 2194964, G01M17 / 04, from 07/27/2000, prototype). In addition to these main units, there is a mechanism for selecting backlash and bearing arrangements for active and passive grips. The mechanism for selecting the backlash is made in the form of a rocker arm connected to a passive grip and interacting with it elastic pushers and rigid stops located on the frame. In this case, the bearing supports of the passive grip are installed with the possibility of rotation about their longitudinal axis. The twist angle indicator of the elastic element is made in the form of two angular position sensors mounted immovably relative to the frame and connected to active and passive grippers, respectively. The stand uses a hydraulic drive.

It is argued that the stand eliminates, when testing the torsion, the forces that prevent it from self-unrolling due to the absence of backlash in the connections of the active and passive grippers with the torsion heads. The actuator used requires constant pressure during testing and appropriate monitoring, which creates a weak point in the design.

The objective of the present invention is to improve the design and expand the technical capabilities of the stand for testing torsion bars for a long draft.

The technical result consists in creating a design of a stand for testing the long-term draft of torsion bars with the ability to turn off the power drive.

This goal is achieved by the fact that in the known stand for testing torsion bars for twisting, containing a monitoring and control system, a frame, replaceable active and passive grippers, a loading mechanism associated with an active gripper, the latter has a means for stopping the test torsion bar in its twisted position in the form of an exhaust spring-loaded retainer, while the passive gripper is mounted on a movable stand that can move along the body for a length determined by the longitudinal dimension of the tested torsion bar and has a limiter for the movement of the replaceable grip, and between the active and passive grips there is an indicator of the torsion twist angle.

The proposed technical solution is schematically illustrated by the drawings, where Fig. 1 a and b show a top and side view of the stand (D-D), with passive (C) and active grippers (B), and Fig. 2 a) shows an example of implementation captures and a side view of the active capture (figure 2 b).

The stand contains a housing 1, on which a fixed post 2 is located, a movable post 3 with the possibility of axial movement relative to the axis of the tested torsion shaft; electromechanical drive 4 with a reversible connection scheme, which allows the torsion shaft to be twisted with both the left and right directions of twisting and is removable a sliding protective casing 17, which prevents the scattering of fragments in the event of a possible breakdown of the tested torsion shaft (Fig. 1a).

The body of the stand is a welded metal structure installed on the supporting surface using adjusting screws 5 (Fig. 1b). On the upper surface of the housing is fixed a stationary post 2, which has a movable rotating shaft 6, installed in the bearing unit 7. On one side, the shaft 6 is connected by means of an elastic sleeve-finger coupling 8 to the output shaft of the worm gear 9, which in turn is connected with the help of an elastic sleeve- the finger clutch 10 is connected to the electric motor 11. At the other end of the shaft 6 there is a square hole in which a replaceable flange 12 is installed, having a hole in the center that corresponds in geometry to the end of the torsion shaft being tested, and along the peripheral cylindrical part there are wedge slots for the pull-out spring-loaded retainer 13 of the unit stopping 14. At the end of the flange 12 there is a dial 18 with a scale applied. At the opposite end of the body there is a movable post 3, which has the possibility of longitudinal movement and subsequent fixation at a distance corresponding to the length of the torsion shaft. In the lower part of the rack, an element 19 of the twist angle indicator, for example, of a laser type, is fixed. In the upper part of the rack there is a removable insert and fixable insert 15 with a center hole corresponding to the end of the torsion shaft being tested. The force meter, which performs the function of the mentioned torque meter and is included in the monitoring and control system, has a standard design and is not shown here.

The design of the stand excludes the possibility of shear, bending and tensile stresses in the tested torsion shaft.

The stand for testing torsion bars for twisting works as follows.

A removable flange 12 with a central hole of the corresponding size and geometry of the torsion shaft under test and corresponding wedge slots for the possibility of subsequent fixation at the given torsion shaft torsion angles is installed and fastened into the stationary post 2. The latch 12 is set to zero position. A corresponding replaceable liner 15 is installed in the movable rack. The movable rack is installed and fixed in a position corresponding to the length of the test movable shaft. The torsion shaft under test is installed in the holes of the replaceable flange 12 and liner 15. The insert 15 is fixed soft limiter 16 preventing axial displacement of the insert 15. Mounted protective casing 17. According to the test program executed on the torsion bar twisting predetermined angles (α, or α ₁ or β or β ₁₎ and the predetermined direction of twist. When the specified twisting angles are reached, the replaceable flange 12 is fixed with the retainer 13. Temporary holding of the torsion shaft in this state is carried out according to the test program. Then, the flange 12 is unlocked, the lock 13 is removed from the locking position, and due to the operation of the drive, the test shaft returns to its original position.

The indicator of the angle of rotation allows you to control the readings by the value of the angle of twisting of the torsion bar and, after removing the load, the value of the angle of residual deformations. Then the tested torsion shaft is removed.

As shown above, by fixing the position of the twisted torsion bar, the stand allows you to turn off the power drive and maintain the torsion bar in a twisted state for a long time. The design documentation was completed for the proposed structure, and the prototype was put into operation.

Claims (1)

A test bench for torsion bars, containing a monitoring and control system, a frame, replaceable active and passive grippers, a loading mechanism associated with an active grip, characterized in that the latter has a means for stopping the tested torsion bar in its twisted position in the form of a pull-out spring-loaded latch, while passive the gripper is installed on a movable stand, which can move along the body for a length determined by the longitudinal dimension of the tested torsion bar, and has a movement limiter for the replaceable passive grip.

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