SU1236221A1 - Method of testing hydraulic shock absorbers - Google Patents

Description

ten

15

The invention relates to mechanical engineering and can be used to test, for example, hydraulic automotive shock absorbers.

The aim of the invention is to increase the test performance due to the fact that the given speed varies linearly in time from the minimum to the maximum value.

FIG. 1 shows a graph as a function of time and speed of movement of the rod; in fig. 2 is a diagram of the implementation of the proposed method, for example, with the help of a cam mechanism.

A device for implementing the proposed method comprises a fixed support 1, a dynamometer 2 with a writing device 3, interacting with a moving tape 4.20

The shock absorber under test 5 is attached to the dynamometer 2, and its rod 6 is attached to one end of lever 8 spring-loaded 7. At the other end of lever 8 there is a slider 9 interacting with the cam mechanism 10. The lever 8 also interacts transversely with limit switches 11 and 12.

At a speed varying linearly with time, i.e. with a uniformly accelerated rod movement, it is possible to construct a characteristic of the shock absorber operation in one double stroke.

Consider the rod motion equations (1) and the expression for the resistance force of the shock absorber (2).

12362212

We register the external force applied to the damper rod as a function of the time of motion t. As a result, we obtain the dependence shown in FIG. 1. Shifting the t axis by the value of Ma (Fig. 1) in accordance with (2), inputting t another scale (V at) can proceed to the dependence of the resistance of the shock absorber (Q) on the speed of the rod (V). Thus, a characteristic of the shock absorber operation is constructed.

To ensure a uniformly accelerated motion of the rod with acceleration, the dependence of its movement on time has the form

at2

X - (A)

25

To ensure such a law of motion, one can use, for example, a cam mechanism.

The method is carried out as follows.

The test shock absorber 5 is fixed to the fixed support 1 through a dynamometer 2 with a recording device 3 fixed to it with a tape-testing mechanism (not shown). Using the cam mechanism 10, the cam is shaped according to the law (4), through the slider 9, moves (ice along two shoulder levers 8 forcefully move the rod 6 of the shock absorber 5 at a speed varying linearly with time (this is provided by the cam profile). To ensure the compression stroke of the shock absorber 5, the lever 8 is pressed to the cam by the spring 7. Ator 5 performs a double stroke during which the movable belt 4 to recorded current value applied to the damper force Fg. For the start and end of recording power RDH set DIP switches 11 and 12 on and off vklyuchayupsche tape drive 4.

mf k (x) x F.

X x

M FSH (1)

de X - rod displacement coordinate 6 J

rod speed, rod acceleration is the mass of the moving part of the shock absorber, including fluid and external force applied to the rod. Q k (x) .. X Fg - (2).

From (2) it can be seen that with uniformly accelerated movement of the rod (x a const), the resistance force of the shock absorber is less than the external force by a constant value Ma. Under constant acceleration, the speed V of the movement of the rod is

V at (3))

where t is the current travel time of the shock absorber.

Ensuring equally accelerated stem with acceleration depends on time

at2

X - (A)

To ensure such a law of motion, one can use, for example, a cam mechanism.

The method is carried out as follows.

The test shock absorber 5 is fixed to the fixed support 1 through a dynamometer 2 with a recording device 3 fixed to it with a tape-testing mechanism (not shown). Using the cam mechanism 10, the cam is shaped according to the law (4), through the slider 9, moves (ice along two shoulder levers 8 forcefully move the rod 6 of the shock absorber 5 at a speed varying linearly with time (this is provided by the cam profile). To ensure the compression stroke of the shock absorber 5, the lever 8 is pressed to the cam by the spring 7. For one revolution of the cam, the rod 6 is amortized Ator 5 performs a double stroke during which the movable belt 4 to recorded current value applied to the damper force Fg. For the start and end of recording power RDH set DIP switches 11 and 12 on and off vklyuchayupsche tape drive 4.

Thus, for one double stroke of the shock absorber rod, on the tape, the dependence of the external force Fg on time t is obtained (Fig. 1). Then, the axis is scaled along the t axis in order to obtain the velocity V at, and then this axis is lifted by an amount of force equal to Ma. The result is the dependence of the resistance force of the shock absorber Q on the speed V, which is a characteristic of the shock absorber.

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Editor L.Gratillo

Compiled by A. 1ashkin

Tehred M.Hodanich Proofreader M.Maksinishynets

Order 3076 / 39Ction 880 Subscription

INSIGHTS of the USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production printing company, Uzhgorod, Projecto st., 4

Claims (1)

METHOD FOR TESTING HYDRAULIC SHOCK ABSORBERS of vehicles, namely, that the shock absorber rod is moved at a predetermined speed in one double stroke, the current value of the force causing this movement is measured and recorded, and the value of the shock absorber resistance, characterized in that, in order to increase productivity , the set speed is changed linearly in time from the minimum to the maximum value and vice versa. yo sae o) yo