SU1767382A1 - Device for checking vibration damper - Google Patents

Abstract

Use: instrumentation and to record the characteristics of dampers when tested on the stands. Essence: the device comprises a frame 1, on which a spring 2, a column 3 and a pipe 4 are mounted. A lever 5 supported through a spring support is pivotally attached to the frame. A load 6 is installed at the other end of the lever. The support has a base to which the rocker arm 8 is hinged. The support part of the rocker arm is provided with rollers 9. To install the tested extinguisher, the base of the support and the bed are equipped with rollers 10. The checked damper 19 is installed with its mounting heads on the rollers bases of support and bed. The rack is provided with a stop 20, and the lever is equipped with a pusher 21. The oscillations of the dynamic load stand system with a spring lever with a checked vibration damper are recorded with a pencil on the tablet. In this case, the tablet moves under the influence of the force of gravity of the suspension after the tablet retainer is opened by the pusher. The smoothness of the movement of the tablet is ensured by pneumatic damping when the tablet is moved in the pipe. According to damped oscillations, the efficiency of the vibration damper is judged. 4 il. SP

Description

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The invention relates to the field of test equipment, mainly for testing vibration dampers (shock absorbers) of vehicles.

Devices are known for checking vibration dampers by means of a force action and recording the characteristics of inelastic resistance forces, which they develop in this case (Cl. G 01 M 17/04, 662802, 651226, 118560, etc.). The known devices contain a frame mounted on the frame loading the actuator and the recording device. The loading drive is made in the form of an eccentric mechanism for harmonic force action or in the form of a hydropneumatic cylinder for compression — augmentation of the vibration damper (ed. St. 612155, 1107027, 575532, US Patents 2,660,678, France 2,185,187).

The recording device has an elastic element (spring or torsion), which is elastically deformed by the forces of resistance of the vibration damper and fixes the working diagram of the vibration damper on the tablet. When using strain gauge equipment, the change in resistance forces is recorded on the screen of the oscilloscope, on photo or magnetic media. In the case of using power cylinders, the efficiency of dampers is checked by the time of their compression or expansion. A disadvantage of the known stands is the low accuracy of checking dampers. The deformation of the elastic element of the registering device introduces an error of up to 30%; when using strain gauge, the error of electrical measuring equipment is added. Evaluation of performance by time of compression-age is approximate.

Known devices (stands) for checking dampers in the spring suspension of vehicles using the methods of damped or forced vibrations (ed. St. 624135, 523323, 706733, etc.). One-time or periodic impacts on the vehicle are made and, by the reaction of its spring suspension, the technical condition of all vibration dampers is judged. The disadvantage of these devices is the low accuracy of the performance evaluation, since It is not possible to check each vibration damper separately. In addition, during vehicle oscillations, lateral forces occur on the springs, which distort the recording of oscillations and

reduce the validity of the evaluation of the dampers.

The closest to the invention to the technical essence is the recording device according to the author. St. 662802, cl. G 01 M 17/04, containing a plate, a housing in which a slider is mounted for movement with a bracket fixed on it and hingedly attached

0 there is an oscillation head with a head, the second head of which is pivotally attached to a lever rigidly connected with a writing device and an elastic element. It is equipped with guides, spring,

5 fixed on the bracket and a cable system connecting the tablet with the lever, the spring-loaded tablet being movably mounted on the guides and connected through the fixed block to the throttle through the pulleys, two of which are fixed on the bracket and one on the lever coaxially to the hinge fastening of the head of the extinguisher, with both ends of the cable attached to the body. Disadvantage of this

5 of the device is the low accuracy of the damper check. The deviation of the elastic element under the influence of the force of resistance of the damper in this device introduces an error of up to 15% to the evaluation of the performance of the damper of vibrations.

The aim of the invention is to improve the accuracy of checking vibration dampers, which ensures the calculated smoothness of travel, reduces wear and damage of vehicles and means, and increases traffic safety. The goal is achieved by the fact that a device for testing vibration dampers, comprising a lever, one end of which is pivotally connected to

0 bed, and at the other end is attached with the ability to move the load, in the middle part of the lever fixed on the spring and recording device in the form of a movable tablet placed in linear guides rigidly attached to the rack rigidly connected to the bed, attached to the tablet one end of the cable, which is passed through a pulley attached to the linear guides,

0 a pencil is attached to the lever, which has the ability to interact with a movable tablet, is equipped with a suspension and a guide tube made with a number of holes located on its

5 of the surface of the tablet fixed to the linear guides by a pusher of the retainer placed on the lever, while the suspension is attached to the free end of the cable placed in the guide tube, and the lever support is made in the form of a disk pivotally connected to the rocker, the supporting part of which supplied with rollers.

The efficiency of absorbers is evaluated by damping by decrement, which is translated into a resistance parameter. The decrement is determined by decreasing the amplitudes for one period of oscillation of the spring-loaded mass using a vibrogram of damped oscillations of the lever with a load recorded on the tablet. The vibration amplitudes recorded on the vibrogram do not depend on the uneven movement of the tablet, they accurately reflect actual deviations of the lever with a load along the spring axis from the zero line. Non-uniformity of motion affects only the vibration period reflected in the vibrogram and does not affect the performance assessment . The check of dampers of oscillations by the method of damped oscillations by the decrement transformed into the resistance parameter is more accurate than the evaluation of the health of the damper by the working diagram. Accuracy is due to the independence of the result of the stiffness of the elastic element.

Figure 1 shows a device for testing vibration dampers; figure 2 - recording device; on fig.Z - knot opirzni lever on the rollers of the rocker; figure 4 - node leverage on the rollers of the rocker arm.

In the figures indicated: 1 - bed; 2 - spring; 3 - stand; 4 - pipe; 5 - lever; 6 - cargo; 7 - disk; 8 - rocker; 9 - rollers; 10 - rollers; 11 - pencil; 12 - guides; 13 - pulley; 14 - tablet; 15 - thrps; 16 - suspension; 17 - holes; 18 - a clamp; 19 - vibration damper; 20 limiter; 21 - pusher.

The invention is as follows. A spring 2, a post 3 and a pipe 4 are mounted on the frame 1. A lever 5 is pivotally attached to the frame, supported through a spring support. A load 6 is mounted at the other end of the lever. The load can be fixed on the lever at different distances from the hinge axis and oscillate with the lever on the spring relative to the hinge. The lever support is made in the form of a disk 7 pivotally connected to the rocker 8. The support part of the rocker arm is equipped with rollers 9. To install the test vibration damper, the support disk and the base frame are equipped with rollers 10. A pencil 11 is mounted on the lever, opposite the pencil on the rack are rigidly fixed - linear guides 12 and the pulley 13. The rack is rigidly connected to the bed. In the linear guides, the tablet 14 is mounted for movement, to which the cable 15 is attached, passed through the pulley and attached by the second end to the suspension 16. The last dimension Shchen in a pipe formed with a number of holes 17. Pencil has the ability to interact with the tablet. The initial position of the tablet in the linear guides is determined by a latch 18 mounted on the linear guide. The latch is located in the cutout of the tablet. Tested and damper 19 set their heads on the rollers of the disk support and bed. The rack is equipped with a limiter 20, and the lever - the pusher 21.

To check the operation of the oscillation damper, a force is applied to the lever 5, lowering it to the restrictor 20. The spring 2 and the vibration damper 19 are compressed. Termination of the action leads to the appearance of free damped oscillations of the lever 5 with a load 6 on the spring 2.

At the same time, the lever 5 pushes the retainer 18 with its pusher 21 and the tablet 14 under the influence of the weight of the suspension 16 begins to move in the linear guides 12. At the same time, the pencil 11 mounted on the lever 5 records a vibrogram of damped vibrations on the tablet. This curve determines the technical condition and the vibration damper resistance parameter 19. Suspension 16 moves in pipe 4, which eliminates its deviations from the vertical and, due to the pneumatic resistance of the holes 17, ensures smooth movement of the suspension and the plate.

When the lever oscillates with the load, the support arm 8 rotates respectively relative to the hinge, which ensures centering of the load on the spring 2 and eliminates its distortions, and therefore, increases the accuracy of control of the vibration damper. The rollers 9 on the support surface and the rocker arms 8 reduce to zero the influence of friction between the rocker arm 8 and the lever 5 on the evaluation of the forces of inelastic resistance developed by the vibration damper.

By vibrogram of damped oscillations of the lever with a load, regardless of the uneven movement of the tablet, the amplitudes of the oscillations of the lever are accurately recorded. By decreasing (decreasing) these amplitudes, a quench resistance parameter is calculated, which characterizes its performance. The resistance parameter is the main criterion for evaluating the performance of absorbers and is defined as the ratio of the resistance force to the compression rate and the growth rate of the oscillation damper.

Using the vibrogram, the resistance parameter D kN s / m is calculated by the formula:

/ "{I 1 where C - spring stiffness N / mm;

In - moment of inertia of the lever with the load, kg / m;

In is the distance between the axes of the spring and the hinge of the lever, m;

ао, at - initial and next after a period of amplitude of oscillations measured by vibrogram.

Evaluating the performance of vibration dampers by the resistivity parameter is very effective and universal.

After checking the damper and the complete cessation of oscillations of the lever, the tablet 14 is returned to its original position and its position is fixed by the latch 18, inserting it into the slot of the tablet.

When the tablet returns to its original position, pencil 11 draws a straight line marking the axis of oscillation of the lever with the load (zero line).

The proposed device can be used to control vibration dampers (shock absorbers) of rail carriages of all types, cars, tracked and wheeled tractors, all-terrain vehicles, etc.

Proven oscillation dampers provide the calculated smoothness of the course of vehicles, reduce the dynamic effects on the sprung mass and the path. This allows to reduce the cost of repairing the rolling stock and the track, to increase their service life, the safety of the transported goods, the comfort and safety of passengers. At the same time, the cost of the device is 3-4 times less than the cost of known structures for checking vibration dampers.

Claims (1)

The invention The device for checking vibration dampers, which contains a lever, one end of which is pivotally connected to the frame, and at the other end is loaded with a load, in the middle part of the lever a spring is installed and the recording device is in the form of a movable plate placed in linear guides rigidly attached to a rack rigidly connected to the frame, one end of the cable is attached to the tablet, passed through a pulley attached to linear guides, a pencil is attached to the lever, which has the ability to interact with a movable plate, in order to improve the accuracy of checking the vibration damper, it is provided with a suspension and guide tube holes located on its surface, a plate lock mounted on the linear guides, a lock pusher placed on the lever, while a suspension is attached to the free end of the cable and placed in the guide tube pa lever is formed as a disc pivotally connected to the rocker, the supporting part of which is provided with rollers. Ultrasound 7 FIG. 2 And ГгiwKwax Tte -ГЧ v№ : “G Lf  us 4