UA124924U - PORTABLE DEVICE FOR DIAGNOSTICS OF SHOCK ABSORBERS IN A SUSPENSION OF A VEHICLE - Google Patents

Abstract

The portable device for the diagnosis of shock absorbers in the vehicle's suspension includes a device for the excitation of harmonic oscillations of the unsprung part of the suspension, as well as a device for measuring and recording the current value of the vertical load on the wheel. The device further comprises a jack for lifting the vehicle by the transverse (longitudinal) suspension lever, by the bridge or by the wheel. The excitation device is made in the form of additional mass, which is mounted during the wheel rim test. And the device of measurement and fixing is the measuring instrument of an angle of inclination (inclinometer), which is mounted for the time of tests on the cross (longitudinal) suspension lever or the bridge of the car.

Description

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The useful model belongs to motor transport, namely to the means of maintenance and repair of cars, and can be used in assessing the technical condition of the shock absorbers of the car suspension.

When testing the suspension 3, in order to determine the technical condition of the shock absorbers, devices are used that excite the suspension with test power signals and devices that record the reaction of the suspension to the test signal. Further processing of the reaction gives the result. At the same time, in diagnostic devices, as a rule, one of two types of suspension reactions is used - these are the vibration parameters of the sprung part or the vibration parameters of the vertical load on the wheel. Despite the fact that both groups of parameters characterize the technical condition of the shock absorber, it should be noted that the first group of parameters directly characterizes the smoothness of the ride, that is, the comfort of the car, while the second group of parameters directly characterizes the force contact of the tire with the road, that is, the safety of driving. At the same time, portability saves production space and makes diagnostics of shock absorbers cheaper.

The well-known "Car Shock Absorber Tester", the basis of which is a vibration detector in the form of a seismograph, sensitive to vertical movements of the body (suspended part). A console with an indicator of the number of oscillations is placed in the same housing as the detector. During testing, the tester is attached to the fender of the car from the side of the tested shock absorber, and from the same side the suspension is excited by a short power pulse applied to the body by the operator's muscular strength. The formulation of the report on the condition of the shock absorber is carried out by the number of vibrations of the body up and down. This tester is claimed in US patent 111.

There are several reasons that prevent obtaining the expected technical result - a combination of portability and high accuracy when using this tester. The first is that the vibration parameter of the sprung part is used as the response of the suspension, namely the number of damped vibrations. It is known |2, p. 105, 106), that this group of parameters, in addition to the shock absorber resistance coefficient, depends on the value of the sprung mass, as well as on the stiffness of the suspension. In this technical solution, these parameters are not taken into account, which reduces the accuracy of the diagnostic result. The second reason for the lack of diagnostic accuracy is due to the priority of smoothness parameters over safety parameters. Available on

It should be borne in mind that a shock absorber recognized as serviceable due to the smoothness of its movement may not be able to maintain the necessary contact with the road on the road. The third reason for low accuracy is due to contradictions between the statistical nature of the suspension load on the road and the single impulse load during testing. Any car suspension has significant friction, which is realized during the test action in a random way and can significantly affect the result. In addition, it should be added that the device assumes that the suspension excitation conditions in the test mode do not correspond to the conditions of real work on the road. In the test mode, excitation is carried out from the body by the operator's muscular power, and on the road - from the wheel when hitting a bump. That is, the direction of action of the exciting force is directly opposite. The very method of presenting the test results should also be included among the important reasons. The amount of vertical oscillations of the body after impulse action very roughly characterizes the damping effect of the shock absorber and suspension, in particular due to quantization errors.

The well-known "Tester of shock absorbers on a 5AT BV M-TAOMIS car", which includes an ultrasonic sensor of the vertical movement of sprung parts, a control unit and a unit for processing test results. During testing, the tester is placed on the wing of the car and the suspension is excited from the side of the body with a short pulse from the muscular strength of the operator. The diagnosis is formulated as a result of the processing of the impulse transient function, which is obtained with the help of an ultrasonic sensor of vertical movements of the body. The tester is described on the manufacturer's website.

The main reasons that prevent obtaining the expected technical result are the combination of portability and high accuracy when using this device, mainly the following

The same as in the previous technical solution. In addition, it should be noted the decrease in the effectiveness of the tester due to the high labor intensity of the tests, due to the need for preliminary adjustments to the combination of the axis of the sensor and the ultrasound emitter. If the axes are not aligned in advance, during the tests, due to body roll during oscillations, signal loss is possible.

A stand for testing the suspension of a vehicle is also known, which contains as a device for excitation of oscillations a mechanism for dropping the axle of the car from a certain height, and as a device for fixing the response of the suspension - a sensor for registering the position of the body |4)І. The reset mechanism consists of a support plate with grooves and a lever with a comb part, on which the wheel rests in different phases of the stand. The reset mechanism is driven from a third-party electric motor through a shaft with a segmental groove. A step test signal is implemented in the stand, and the output characteristic of the tests is the transient function (2, pp. 116-120). The significant disadvantages that prevent the combination of portability and high accuracy of this technical solution include the lack of portability, the high cost due to the cost of the stand, the need for a production facility, engineering networks, as well as the known contradiction between the statistical character of the suspension load on the road and the single (step ) load during testing.

The closest device (prototype) of the same purpose to the claimed device is a stand for testing the suspensions of the IB car). It includes a device for exciting wheel harmonic oscillations and a device for measuring and recording the current value of the vertical load on the wheel. The wheel rests on the platform, which during the test is driven into oscillating motion by the stand's electric motor. The technical condition of the shock absorber is assessed, in accordance with the recommendations of Ey5AMA, by the dimensionless coefficient K:

K-RO/RB, (1) where RO is the minimum value of the vertical load on the wheel during the measurement cycle;

RB - static vertical load on the wheel.

The coefficient shows the share of the coupling weight in relation to the static load, which can be realized in extremely unfavorable conditions of suspension oscillations (as a rule, at the natural frequency of oscillations of unsprung masses). For a working shock absorber, the coefficient is equal to 0.4...0.7, for a faulty one, it is 0...0.4. The static vertical load on the wheel is determined in advance, immediately before scanning. During the test, the wheel rests on the platform, which is oscillated by the stand's electric motor.

The main reason preventing the achievement of the expected technical result - the combination of portability and high precision - is the lack of portability, as well as the high cost of the stand itself and the need for production space for its placement. This makes it impossible to use the method in field conditions, small businesses and garages.

The basis of the useful model "Portable device for diagnosing shock absorbers in the car suspension" is the task of obtaining an inexpensive tool in a portable format comparable in accuracy and reliability of diagnosis with a stationary stand.

З The task is solved by the fact that, in comparison with the known stand for testing car suspensions, which contains a device for exciting harmonic oscillations of the unsprung part of the suspension, as well as a device for measuring and fixing the current value of the vertical load on the wheel, according to a useful model, the device additionally contains a jack for lifting the car by the transverse (longitudinal) lever of the suspension, by the bridge or by the wheel, the excitation device is made in the form of an additional mass that is mounted on the rim of the wheel during the tests, and the measuring and fixing device is an inclination angle meter (inclinometer) that is mounted at the time tests on the transverse (longitudinal) lever of the suspension or bridge of the car.

The effectiveness of the claimed device is due to its portability and high accuracy. Its implementation does not require an expensive, material-intensive stand, production areas, engineering networks, or significant operational costs. With its help, a conclusion about the technical condition of the shock absorber can be obtained after running the car on a flat section of road with an asphalt concrete surface, up to 1.0 km long. Thus, the declared technical solution ensures high accuracy of diagnosis and makes it available in the conditions of small enterprises and auto repair shops, which indicates the solution of the given technical task. The technical result - a combination of portability and high accuracy - is achieved due to the advantages of using additional masses to excite harmonic oscillations, without involving stands and spending additional energy, as well as due to the use of an inclination angle meter (inclinometer) as an indirect indicator of the vertical load on the wheel. The technical result is also an expansion of the range of technical means for diagnosing shock absorbers.

The essence of the indirect measurement of interaction forces in the connection "tire - support surface" is as follows. It is known (2, p. 242-243) that the radial deformation of the tire is proportional to the vertical load, that is, the vertical load P can be determined as follows:

REK, (2) where K is the proportionality factor; n - radial deformation of the tire.

On the other hand, the deformation of the tire by the amount y leads to the rotation of the suspension lever by an angle a, therefore, by measuring the angle of rotation of the lever, it is possible to determine the deformation according to the formula: 60 n- "shcha, (3)

where r is the length of the suspension lever.

Then the dimensionless coefficient characterizing the condition of the shock absorber is determined as follows:

K-RO/RBAK CHO VZHK tou-yu9VLoU, (4) where RO, P5 - minimum for the scan cycle and static vertical load, respectively;

B, y - angles of rotation of the transverse (longitudinal) lever of the suspension or bridge relative to the accepted reference point at the minimum scan cycle and static vertical load, respectively.

Considering the equality of the tangents of small angles expressed in radians, the actual angles, we finally get:

K-v/u. (5)

Placing the tilt angle meter (inclinometer) on the suspension arm (bridge) of the car makes it possible to indirectly measure the vertical load on the wheel, and in relation to the minimum value of this load during the test cycle to the static load - to formulate a conclusion about the technical condition of the shock absorber. At the same time, a harmonic signal in the form of a centrifugal force with known parameters is applied to the input of the device.

The declared useful model consists of three separate devices: a jack for lifting the car by the transverse (longitudinal) lever of the suspension, by the bridge or by the wheel, the device for exciting harmonic oscillations, made in the form of an additional mass, and the measuring and fixing device, which is a measurer of the angle of inclination ( inclinometer).

The device is explained by the drawings, where in fig. 1 shows a fragment of recording and processing of test results, in fig. 2. placement of additional mass on the inner surface of the wheel rim is presented; 1 - additional mass.

Along the vertical axis, fig. 1, there is a vertical load on some scale Y, along the horizontal axis is the delayed time with a division price of 0.2 seconds. The RO value is the reading of the inclinometer at the initial state of the car and corresponds to the static vertical load on the wheel (together with the driver) on the U scale. The RO value corresponds to the reading of the inclinometer at zero vertical load on the same U scale (when the wheel is lifted by the lever or by the wheel). The RA value is the maximum value (amplitude)

From a vertical load from the action of an unbalanced mass. It is obtained by recording the evidence of the inclinometer during the coasting of the car at a certain speed, corresponding to the resonant frequency of unsprung masses. This frequency is measured in hertz and is obtained by counting the number of periods in a certain period of time. Based on the data of fig. 1, frequency II-2.7/0.2-13.5 Hz.

The claimed utility model is implemented as follows.

Before the test, it is necessary to check the pressure in the tires of the wheels; the suspension must be warmed up by driving on a rough road for at least 15 km. An additional mass in the form of a profiled plate weighing about t-200 g is attached to the inner surface of the wheel rim, for example 13", in the suspension of which the efficiency of the shock absorber is evaluated, with the help of double-sided tape. The distance from the center of rotation of the wheel to the center of mass Kgr is about 160 mm. Instead of plates, it is possible to use standard weights for wheel balancing, for example blocks of 100 g (4 x 25 g), or other denominations. When the car is moving, the unbalanced mass creates vertical sinusoidal oscillations from the centrifugal force E:

E-t"Agryu?"2-t"VAgr"(Ma/3.6/8K72-t"Agr'(2lug, (6) where o is the angular speed of rotation of the wheel, 1/s;

VAK - wheel radius, m;

T-18 Hz - the frequency of oscillations of the exciting force.

Under these conditions, the centrifugal force is E-408.89 N. The frequency of oscillations is related to the speed of the car by the following ratio:

Ma-3.6" AKT. (7)

During the tests, a tilt angle meter (inclinometer) is mounted on the transverse (longitudinal) lever or bridge of the car. The readings of the inclinometer are fixed and adjusted to the static load of RB5 (initial state of the car with the driver). Then, with the help of a jack, the car is lifted by the transverse (longitudinal) lever of the suspension, by the bridge or by the wheel until the moment of separation of the wheel from the supporting surface. In this position, zero vertical load on the wheel is fixed; it is put in accordance with the indication of the RO inclinometer. The difference in the evidence of Р - РО is the range of possible changes in the vertical load on the wheel. Within this range, the dependence of the vertical load on the angle of inclination of the transverse lever (longitudinal lever, bridge), due to the linear dependence of the tire deformation on the load, will also be linear. Next, the car is coasted 60 from the speed corresponding to resonant oscillations to a complete stop with the recording of the inclinometer readings. Find the minimum difference "P - RA" per cycle. The minimum RO-RB-RA during the test is fixed and the coefficient K is determined:

K-ROB/RB. (8)

The maximum amplitude of forced oscillations of the unsprung part is usually observed at the resonance frequency. Resonance frequencies and unsprung masses of suspensions of different cars differ significantly depending on the size of the wheels, mass values, stiffnesses, therefore, to obtain comparative results for wheels of different sizes, a different frequency is recommended as a standard: for 13" wheels, 0-18 Hz, for 14" 10-15 Hz; for 13" 0-12 Hz. If the resonant frequency of It differs from the recommended standard 0, the centrifugal exciting force will change accordingly, which will lead to a proportional change in the amplitude of the vertical load.

For its correction, it is necessary to find the value of the correction equal to (1/10)772 and multiply the value of the amplitude of the vertical load by this correction, if 1-10 and, accordingly, divide it if it is 51o.

To obtain comparative data, it is also desirable that the centrifugal force is constant at resonance for different wheel diameters. This becomes possible if the conditions presented in the table are met.

Table and Accepted Accepted centrifugal Distance from the center

Size. that the additional wheel to the center of the wheel resonant force at resonant mass, g additional mass Ngr frequency 0, Hz frequency E, N ' M "

High values of the coefficient indicate the efficiency of the shock absorber, lower values - on the contrary, the need for replacement. In the limit, with a complete loss of performance of the shock absorber, the value of the coefficient tends to zero, which corresponds to the separation of the tire from the supporting surface and the loss of controllability of the car. The use of a portable device for diagnosing shock absorbers in the car suspension allows you to get a diagnosis comparable in accuracy and reliability to the stationary version, which provides a reduction in the cost of evaluation and makes it possible to use advanced evaluation technology taking into account the force interaction of the "tire - bearing surface" connection. The implementation of the device allows you to assess the technical condition of the suspension shock absorber in conditions of portability, that is, outside the production premises. The device can be used in field conditions, small enterprises, testing laboratories, motor vehicle enterprises, garages, service stations.

Sources:

Co., Ltd. 1. US Patent 05 463370З3А ZposkK arzogbeg ieziiipd arragaish5; date of submission - November 26, 1984; date of publication - January 6, 1987. 2. Rotenberg R.V. Car suspension, ed. 3rd revised, and add. /Rotenberg R.V. - M.:

Mashinostroenie, 1972. - 392 p. 3. Tester of shock absorbers on a BV BV M-TROMIS car - (Electronic resource| apisieeeesaya-1 U6ZAviozzdayetriepeviv u-5-a-i- ivBaiya-9 953A5-a-i-izraNetia-ZaIapd-ty 4. Patent of the Russian Federation Mo 2320971 Stand for testing the suspension of a vehicle; date of submission - October 31, 2006; date of publication . - March 27, 2008 5. Patent ER 2657674A1 Riyrapk oylg Ashpapdipdep mop Rapggetsdep; filing date - March 29, 2013; publication date - October 30, 2013.

Claims (1)

USEFUL MODEL FORMULA A portable device for diagnosing shock absorbers in the car suspension, containing a device for exciting harmonic oscillations of the unsprung part of the suspension, as well as a device for measuring and fixing the current value of the vertical load on the wheel, which is distinguished by the fact that the device additionally contains a jack for lifting the car by the transverse ( longitudinal) suspension lever, for the bridge or for the wheel, the excitation device is made in the form of an additional mass, which is mounted during the tests on the rim of the wheel, and the measuring and fixing device is an inclination angle meter (inclinometer), which is mounted during the tests on the transverse (longitudinal ) suspension lever or bridge of the car. х х х х и их Й иЯ и х r already kan nak p you E : х их Sho 5 E х N : В х " as yuyu Ki yakozhh v: met U skit kre tozh u oz z moe Ot Ж pkozhyuh Ж : : i z : Z ; х: Хын Хх Zak ani k Zma i ziv pig okis nn ke mA Kli h yi IZ ih kh t. ih M zh p zhisha in xxx i lk Hu to oku t si fsk xx zhi ih Х і і Z З: х х и s so du вс мой бид д M Ж sklum mom i shi uyu wav va a o ZA o KZ i she zh pon doju sim E: shinka Shk M kh: t Z ih (EE OVOFEV K VI VO kh : g oy she kh. pet ож с же ок ж ж nick me - TK KOKO KV VK В В В В З У: сх с БЕЖЖК even ZEEBIBIKIVIK i: a ШЭ В Ж 5 Во 251 ; IF TE KV EKZ VI I I EK I 35 15 I o pe KV : o nen Ks p I U KE OK ev KV V U M NK a nev EI KENE shi hi EKZ K Ku Kt Ne KA KK KY I B MEM KE VKM KOM KE Ж V Ж ME I AM M i V U rok: i: OBII KAH VE KM NNYA ih MAMI MKK B ЖI I M A Ж gu: I M 2 r y le EK Kv Bek ANYA x Ж Oх Ko OH M Ж UU ХХ M 3 ХО Ko Sol: M NK Ne s shk vi yet Shk SHE NI M" - k-x koh Zh shi g. "TSH Z sce Eh H Om p nya hu : ; E se: ZDU: ENN g : ; I GU i IZ i Oh their KU i i nin znih znih for n znin ie zevn zn kon za x x x i z t E I x x i ik x x x U Fig. 1 nin KIN NN she chi che NN not FW" uh 7 shchih y that Ol J: I , : POTU, mya sh J. and Ke M Y y nevy Shi de "BM he, she : I I: . they have KA x 5. B N TSO nanny 7 still in ku sh E, Zk m x y . And ele shinu not ra m SHA H cha ; KU YACH o : E : B TYA, her what in ! i from the river VE: Hrya x i She i rTttu Ye - i SHK x a Meni EN i x rana Y -e i niny Z pu ovi ysva Sy cha Ei i mch i let i zhe, sei x shcha s. ZV y y y VC di Z sia Noy; Hey Mr. i x I V u SA M Kk i E ryh -U8 i SHK More x; х zn Her ny a CHAN Z Z BO U I Mody: tro ta V ee ok Mesy RO DV es 5. HU o y y dyshe she nn nsotsnonninnkntnya V brak 5. scha es a NVK ven y we pe y : y Ye he 7 t, 7 Bra x M child mn nin pan U pyt Ne ov s. NI: as x ZM eye 5th; : "Mu i lascheu ih sche nich She Gn Ya a ON y i zh Z m g ha ih xx Ky TK E N 3 x . Mu vch OO and SUK Z NI Z: HC in B NE. in Ya Well daytime AC, YEAR I . her ; MONEY, ZKOOKH sfih "TAZH GK . uh o Kom A «STA NU U U y lk vana kn DL fe X : KA schy Ku sche N lu lu ch r ra fey Y I u M y li U sche Volo MN AT, 5 kN . 7 z - N «tih schy n i chn NN M I and also "in, : Ai TOJ in i - SHK Z x " 7 : iv in NI Ves DYNY she ; listen she UK ny Oi LEM y , y NU o kh chu U - as she sia U. 2 she she ia V I NV KY NI gy nh sa : sk Zhulya, zi nie chn ee U AN r i o ; Oh TK i Oh ŽY She N dec a Ek y De iiy. and N Fig. 2