As noted above, the steering with the amplifier is an elementary automatic control system with rigid feedback. With an unfavorable combination of parameters, the system of this type may be unstable in this case the instability of the system is expressed in auto-oscillations of controlled wheels. Such oscillations were observed on some experimental samples of domestic cars.

The task of the dynamic calculation is to find the conditions under which self-oscillations could not occur if all the necessary parameters are known to calculate, or reveal what parameters should be changed to stop self-oscillations on the experimental sample if they are observed.

Previously consider the physical essence of the process of oscillation of controlled wheels. Re-turn to the amplifier scheme shown in Fig. 1. The amplifier can be included as a driver when an effort is applied to the steering wheel and controlled wheels from the shocks from the road.

As experiments show, such oscillations can occur during the straight-line movement of the car at high speed, on turns when driving at low speed, as well as when turning the wheels in place.

Consider the first case. When the controlled wheel is rotated from the journey from the road or for another any reason, the dispenser body will begin to shift relative to the spool, and, as soon as the gap δ 1 is eliminated, the liquid will begin to flow into the power cylinder cavity. The steering wheel and the power steering is considered to be fixed pressure in the cavity A will increase and prevent the continuation of the rotation. Due to the elasticity of rubber hoses of the hydraulic system and the elasticity of mechanical connections to fill the cavity A liquid (to create a working pressure), a certain time is required during which controlled wheels will have time to turn to some angle. Under the action of pressure in the cavity of the wheels will begin to rotate to the other side until the spool takes the neutral position. Then the pressure decreases. The power of inertia, as well as the residual pressure in the cavity, and rotate controlled wheels from the neutral position to the right, and the cycle is repeated from the right cavity.

This process is depicted in Fig. 33, a and b.

The angle θ 0 corresponds to this rotation of controlled wheels, in which the force transmitted by the steering drive reaches the value necessary to move the spool.

In fig. 33, the dependence P \u003d f (θ) is shown, built by curve. 33, a and b. Since the stroke of the rod can be considered a linear function of the angle of rotation (due to the smallness of the angle θ max), the graph (Fig. 33, c) can be considered as an indicator diagram of the power cylinder amplifier. The area of \u200b\u200bthe indicator diagram determines the work spent by the amplifier to rock the controlled wheels.

It should be noted that the process described can only be observed if the steering wheel remains stationary when the steering wheels are oscillations. If the steering wheel rotates, the amplifier does not turn on. For example, the amplifiers with the drivers of distributors from the angular displacement of the upper part of the steering shaft relative to the bottom usually have this property and do not cause auto-oscilps

When turning controlled wheels in place or when the car moves at a low speed, the oscillations caused by the amplifier differ in nature from the pressure considered during such oscillations increases only in one cavity. The indicator diagram for this case is shown in Fig. 33, G.

Such oscillations can be explained as follows. If at the time corresponding to the rotation of the wheels to some angle θ r, delay the steering wheel, then controlled wheels (under the action of inertia and residual pressure for power in the power cylinder) will continue to move and turn to the angle θ r + θ max. The pressure in the power cylinder will fall to 0, since the spool will be in a position corresponding to the rotation of the wheels at the angle θ r. After that, the power of elasticity of the tire will start rotating the wheel-controlled wheel in the opposite direction. When the wheel turns back to the angle θ R, the amplifier will turn on. The pressure in the system will begin to rise not immediately, but after a while, for which the controlled wheel can turn to the angle θ R -θ max. Rotate to the left at this point will stop, since the power cylinder will enter into work, and the cycle will be repeated first.

Typically, the work of the amplifier, determined by the area of \u200b\u200bindicator charts, is insignificant compared to the work of friction in pile, steering and rubber compounds, and self-oscillations are not possible. When the area of \u200b\u200bindicator diagrams is large, and the work, they are determined, comparable to the work of friction, the unlucky oscillations are likely. Such a case is investigated below.

To find the stability conditions of the system, we have limitations for it:

1. Controlled wheels have one degree of freedom and can be rotated only around a squash within the gap in the amplifier distributor.
2. The steering wheel is rigidly fixed in a neutral position.
3. The connection between the wheels is absolutely tough.
4. The mass of the spool and parts connecting it with the control wheels is negligible.
5. Friction forces in the system are proportional to the first degrees of angular velocities.
6. The stiffness of the system elements is constant and does not depend on the value of the corresponding displacements or deformations.

The remaining admitted assumptions are negotiated during the presentation.

Below are the stability of steering with hydraulic motors mounted for two possible options: with long feedback and short.

The structural and calculated scheme of the first option is shown in Fig. 34 and 35 solid lines, second - bar. At the first embodiment, feedback acts on the distributor after the power cylinder has rotated the controlled wheels. With a second embodiment, the dispenser housing moves, turning off the amplifier, simultaneously with the stream of the power cylinder.

First, consider each element of a diagram with long feedback.

Steering gear (on the structural scheme is not shown). Rotate the steering wheel on some small angle A causes a force t c in a longitudinal pull

T C \u003d C 1 (αi R.M L C - x 1), (26)

where C 1 is the rigidity of the steering shaft and longitudinal thrust below; L C - fat length; x 1 - moving the spool.

Distributor drive. To drive the control of the switchgear, the input value is T C, the output is the offset of the spool X 1. The drive equation, taking into account feedback at the angle of rotation of the controlled wheels θ and by pressure in the system P, has the following form at T C\u003e T N:

(27)

where k o.s - the coefficient of feedback force at the corner of the rotation of the controlled wheels; C n - rigidity of centering springs.

Distributor. The oscillations caused by the amplifier of the moving car are associated with the alternate inclusion of the one, then another cavities of the power cylinder. The distributor equation in this case has the form

where q is the amount of fluid entering the pipelines of the power cylinder; x 1 -θl s k o.s \u003d Δx - shift of the spool in the case.

The function f (δx) is nonlinear and depends on the design of the spool of the distributor and pump performance. In the general case, with a given characteristic of the pump and the design of the distributor, the amount of liquid q entering the power cylinder depends on both the Δx of the spool in the case and on the pressure difference ΔP at the inlet to the distributor and output from it.

The amplifier distributors are designed so that, on the one hand, with relatively large technological tolerances on linear dimensions, have a minimum pressure in the system with a neutral position of the spool, and on the other, the minimum shift of the spool to bring the amplifier into action. As a result, the spool distributor of the amplifier according to the characteristic Q \u003d F (Δx, Δp) is close to the valve, i.e. the value q does not depend on the pressure Δp and is only a spool displacement function. Taking into account the direction of the power cylinder, it will look like, as shown in Fig. 36, a. This characteristic is characteristic of relay links of automatic control systems. Linearization of these functions was carried out according to the method of harmonic linearization. As a result, we get for the first scheme (Fig. 36, a)

where Δx 0 is the shift of the spool in the housing at which the sharp increase in pressure begins; Q 0 - the amount of fluid entering the pressure line at the overlapped working clips; A - the maximum stroke of the spool in the housing, determined by the amplitude of the oscillations of the controlled wheels.

Pipelines. The pressure in the system is determined by the amount entered into the pressure line of the liquid and the elasticity of the highway:

where x 2 is the stroke of the piston of the power cylinder, the positive direction towards the pressure of the pressure; C 2 - bulk rigidity of the hydraulic system; c r \u003d dp / dv g (v r \u003d volume of pressure highway hydraulic system).

Power cylinder. In turn, the stroke of the strength cylinder is determined by the angle of rotation of the driven wheels and the deformation of the communication part of the power cylinder with controlled wheels and the point of the support

(31)

where L 2 is the shoulder of the effort of the power cylinder relative to the axes of the pivot wheels; C 2 - stiffness of the fastening of the power cylinder, shown to the rod of the power cylinder.

Controlled wheels. The equation of rotation of the controlled wheels relative to the pussher has the second order and, generally speaking, is non-linear. Considering that the oscillations of the controlled wheels occur with relatively small amplitudes (up to 3-4 °), it can be assumed that the stabilizing moments caused by the elasticity of rubber and the slope of the kingle, are proportional to the first degree of the angle of rotation of the controlled wheels, and the friction in the system depends on the first degree of the corner The rotation speeds of the wheels. The equation in a linearized form looks like this:

where J is the moment of inertia of controlled wheels and parts, rigidly related relative to the axes of a king. G is a coefficient characterizing friction losses in a steering wheel drive, a hydraulic system and in the tires of the wheels; N is a coefficient characterizing the effect of a stabilizing moment resulting from tilting tires and elasticity of tire rubber.

The rigidity of the steering drive in the equation is not taken into account, as it is believed that the oscillations are small and occur in the interval of the angles in which the casing of the spool moves to a distance less than the full turn or equal to it. The piece of FL 2 P determines the value of the moment created by the power cylinder relative to the pivota, and the product F radi L E K O.С P is the reaction force from the feedback side by the value of the stabilizing moment. The influence of the moment created by the centering springs can be neglected due to its smallness compared to stabilizing.

Thus, in addition to the above assumptions, the following restrictions are superimposed on the system:

1. efforts in the longitudinal thrust are linearly dependent on the turn of the shaft of the tower, friction in the hinge of the longitudinal traction and in the drive to the spool is missing;
2. the distributor is a link with a relay characteristic, that is, to a certain displacement Δx 0 of the spool in the housing, the liquid from the pump does not enter the power cylinder;
3. the pressure in the pressure line and the power cylinder is directly proportional to the excess volume of the fluid entered into the highway, i.e., the bulk rigidity of the hydraulic system C is constant.

The considered steering control circuit with a hydraulic amplifier is described by the system of seven equations (26) - (32).

The study of the stability of the system was carried out using an algebraic criterion Raus Gurvitsa.

For this, several transformations are produced. The characteristic equation of the system and its stability is found, which is determined by the following inequality:

(33)

From inequality (33) it follows that at a≤Δx 0 oscillations are not possible, since the negative member of the inequality is 0.

The amplitude of the movement of the spool in the housing at a given permanent amplitude of the oscillations of the controlled wheels θ max is from the following relationship:

(34)

If, with an angle θ max, the pressure P \u003d P max, then the move A depends on the ratio of the tightness of the centering springs and the longitudinal thrust C N / C 1, the area of \u200b\u200bthe reactive plungers F R.E, the preliminary compression force of the centering springs T n and the coefficient of the K OS. The greater the ratio C N / C 1 and the area of \u200b\u200bthe jet elements, the more likely it is that the value of A will be less than the value Δx 0, and self-oscillations are impossible.

However, this path of elimination of self-oscillations is not always possible, as an increase in the rigidity of the centering springs and the size of the jet elements, increasing the force on the steering wheel, affect the controllability of the car, and the reduction of the hardness of the longitudinal thrust can contribute to the occurrence of vibrations type Shimmi.

In four of the five positive members of inequality (33), it includes a factor in the parameter of rod, characterizing friction in the steering, rubber tires and damping due to fluid flows in the amplifier. Typically, the constructor is difficult to vary this parameter. As a factory in a negative term, the fluid flow rate Q 0 and the feedback coefficient K O.S. With a decrease in their values, the tendency to self-oscillation decreases. The value of Q 0 is close to pump performance. So, to eliminate the self-oscillating caused by the amplifier during the movement of the car, it is required:

1. Increasing the rigidity of centering springs or an increase in the area of \u200b\u200bjet plungers, if possible, by the conditions of ease of steering.
2. Reducing the pump performance without lowering the rotation speed of the controlled wheels below the minimum permissible.
3. Reducing the coefficient of amplification of feedback K O.S., i.e., reducing the stroke of the spool hull (or spool) caused by the rotation of the controlled wheels.

If these methods cannot be eliminated by self-oscillations, then it is necessary to change the layout layout or enter a special oscillation damper (liquid or dry friction damper) into the steering system with an amplifier. Consider another possible option for laying an amplifier by car with a smaller propensity to excitation of self-oscillations. It differs from the previous shorter feedback (see the bar line in Fig. 34 and 35).

The distributor equations and drive to it differ from the corresponding equations of the previous scheme.

The drive equation to the distributor is viewed at t C\u003e T N:

(35)

2 Equation of the distributor

(36)

where I E is a kinematic transfer ratio between the movement of the distributor's spool and the corresponding movement of the stem cylinder.

A similar study of the new system of equations leads to the following condition for the absence of self-oscillations in a short-feedback system.

(37)

The resulting inequality differs from inequality (33) an increased value of positive members. As a result, all positive terms are more negative with the real values \u200b\u200bof the parameters included in them, so the system with a short feedback is almost always stable. Friction in the system characterized by parameter r can be reduced to zero, since the fourth positive member of the inequality does not contain this parameter.

In fig. 37 The curves of the dependence of the friction values \u200b\u200brequired to waste oscillations in the system (parameter d) on the performance of the pump calculated by formulas (33) and (37) are presented.

The stability zone for each of the amplifiers is between the axis of the ordinate and the corresponding curve. When calculating the amplitude of the oscillations of the spool in the case, it was made minimally possible from the condition of turning on the amplifier: a≥Δx 0 \u003d 0.05 cm.

The remaining parameters included in equations (33) and (37) had the following values \u200b\u200b(which approximately corresponds to the steering cargo car with a carrying capacity 8-12 T.): J \u003d 600 kg * cm * sec 2 / glad; N \u003d 40 000 kg * cm / happy; Q \u003d 200 cm 3 / s; F \u003d 40 cm 2; L 2 \u003d 20 cm; L 3 \u003d 20 cm; c r \u003d 2 kg / cm 5; C 1 \u003d 500 kg / cm; C 2 \u003d 500 kg / cm; C n \u003d 100 kg / cm; F R.E \u003d 3 cm 2.

The amplifier with a long feedback is a zone of instability lies in the range of real values \u200b\u200bof the G parameter, the amplifier with a short feedback - in the range of non-encountered parameter values.

Consider the oscillations of the controlled wheels arising from the turns on the spot. The indicator diagram of the power cylinder during such oscillations is shown in Fig. 33, the dependence of the amount of fluid incoming in the power cylinder on the movement of the spool in the dispenser's housing is viewed in Fig. 36, b. During such oscillations, the gap Δx 0 in the spool is already eliminated by the rotation of the steering wheel and at the slightest shift of the spool causes the flow of fluid into the power cylinder and the pressure growth in it.

Linearization of the function (see Fig. 36, c) gives the equation

(38)

The N in equation (32) will be determined in this case not by the action of the stabilizing moment, but the brutality of tires to twisting in contact. It can be adopted for the system considered as an example N \u003d 400 000 kg * cm / pleased.

The stability condition for a long-feedback system can be obtained from equation (33) by substituting into it instead of expression Expressions (2Q 0 / πa).

As a result, we get

(39)

Members of inequality (39) containing the parameter A in a numerator decrease with a decrease in the amplitude of oscillations and, starting with some sufficiently small values \u200b\u200bof A, they can be neglected. Then the stability condition is expressed in a simpler form:

(40)

With the actual ratios of parameters, the inequality is not observed and amplifiers composed according to a diagram with a long feedback, almost always cause auto-oscillations of controlled wheels when turning on a place with a particular amplitude.

To eliminate these oscillations without changing the type of feedback (and, consequently, the layout of the amplifier) \u200b\u200bcan be reduced to some extent a change in the shape of the characteristics Q \u003d F (Δx), giving it a tilt (see Fig. 36, d), or a significant increase in damping in the system (parameter d). Technically, there are special squeaks on the working edges of the spools to change the form of the characteristics. The calculation of the system for stability with such a distributor is much more complicated, since the assumption that the amount of liquid q entering the power cylinder depends only on the offset of the Δx spool, it can no longer be accepted, because the working segment of the working slots is stretched and the number of incoming Fluid q on this section also depends on the pressure drop in the system to the spool and after it. The method of increasing damping is discussed below.

Consider what happens when turning on the spot if a short feedback is carried out. In equation (37) expression [(4π) (Q 0 / A)] √ should be replaced by an expression (2 / π) * (Q 0 / a). As a result, we get inequality

(41)

Excluding, as in the previous case, members containing the amount and in the numerator, we get

(42)

In inequality (42), a negative term is about an order of magnitude less than in the previous one, and therefore in the system with a short feedback in real combinations of auto-oscillation parameters do not occur.

Thus, to obtain a well-stable steering system with a hydraulicer, feedback should be covered only by almost non-indication links of the system (usually a power cylinder and associated connecting parts directly). In the most difficult cases, when it is not possible to comply with the power cylinder and the distributor in close proximity to one of the other for cleaning the auto-oscillation into the system, the hydrodempefhers (shock absorbers) or hydraulic cylinders - devices transmitting liquid in the power cylinder or back only under the action of pressure from the distributor.

Calculation of steering elements

Loads in the elements of the steering and steering drive are determined based on the following two settlement cases.

According to a given calculated effort on the steering wheel;

At maximal resistance to rotation of controlled wheels in place.

When the car is moving along roads with an uneven surface or when braking with different clutch coefficients under controlled wheels, a number of steering parts perceives dynamic loads that limit the strength and reliability of the steering. Dynamic impact is taken into account by the introduction of the coefficient of dynamism to d \u003d 1.5 ... 3.0.

Estimated effort on the steering wheel for passenger cars P pk \u003d 700 h. To determine the effort on the steering wheel to the maximum resistance to the rotation of the controlled wheels on the spot 166 steering, it is necessary to calculate the moment of resistance to turn according to the following empirical formula

M C \u003d (2r about / 3) v O k / p sh ,

where R o is the clutch coefficient when the wheel is rotated in place ((p o \u003d 0.9 ... 1.0), G K is the load on the controlled wheel, p w - air pressure in the bus.

Effort on the steering wheel for turning on the spot

P Ш \u003d MC / (U A R PK NPP Y),

where U A is an angular gear ratio.

If the calculated value of the force on the steering wheel is superior to the above conditional calculation force, then the steering amplifier is required by car. Steering shaft. In most designs, ᴇᴦο are performed by hollows. The steering shaft is loaded with a moment

M RK \u003d P PK R PK .

Hollow Val Tolera

t \u003d M pk d /. (8.4)

Allowable voltage [T] \u003d 100 MPa.

An angle of the steering shaft twist is also checked, which is allowed within 5 ... 8 ° to one meter of the shaft length.

Steering gear. For a mechanism that includes a global worm and a roller, the contact voltage in engagement is determined.

o \u003d px / (Fn), (8.5)

P X is an axial force perceived by a worm; F is the area of \u200b\u200bcontact of one roller crest with a worm (the sum of the areas of two segments, Fig. 8.4), and the number of ridges.

Axial power

Px \u003d MRK / (R WO TGP),

Material worm-cyanized steel zoh, 35x, 40x, sokh; Material Roller-cement Steel 12HNZZ, 15HN.

Allowable voltage [A] \u003d 7 ... 8MPA.

For a vintage mechanism in the link "Screw-ball nut" define the conditional radial load P 0 to one ball

P sh \u003d 5p x / (MZ COS - $ kon),

where M is the number of work turns, z - the number of balls on one turn, 8 con - an angle of contact balls with grooves (d Kon \u003d 45 O).

Contact voltage determining the strength of the ball

where e is the elastic module, D M is the diameter of the ball, D K - the diameter of the groove, to the CR - the coefficient depending on

curvizons of contacting surfaces (kr \u003d 0.6 ... 0.8).

Allowable voltage [A (w] \u003d 2500..3500 MPa based on the ball diameter. According to GOST 3722-81, the destructive load acting on one ball must be determined.

The calculation of the steering elements is the concept and types. Classification and features of the category "Calculation of the steering elements" 2015, 2017-2018.

A. A. Yenaev

Cars.

Design and calculation

steering controls

Teaching manual

Bratsk 2004.

Design and calculation of steering controls is one of the components of the course project on the "Cars" discipline.

At the first stage of the course design, it is necessary to perform a traction calculation and explore the operating properties of the car using the guidelines "Cars. General. Traction calculation "and then proceed, in accordance with the task, to design and calculate the unit or the car chassis system.

When designing and calculating steering controls, it is necessary to choose the recommended literature, carefully read this benefit. The sequence of work on the design and calculation of steering controls is as follows:

1. Select a vehicle turning method, a steering scheme, the type of steering mechanism, the amplifier layout circuit (if necessary).

2. Perform a kinematic calculation, power calculation, hydraulic calculation of the amplifier (if the steering of the amplifier is provided in the steering).

3. Select the dimensions of the parts and perform the strength calculation.

In this teaching and methodological manual, it is described in detail how to fulfill all these types of work.

2. Purpose, Requirements and Classification

Steering - This is a set of devices that serve to rotate the driven wheels of the car when the driver is exposed to the steering wheel and consisting of steering mechanism and drive (Fig. 1).

The steering mechanism is part of the steering wheel from the steering wheel to the steering tower, and the steering wheel turns on the parts from the steering tower to the rotary pin.

Fig. 1. Scheme of the steering:

1 - steering wheel; 2 - steering shaft; 3 - steering column; 4 - gearbox; 5 - steering bump; 6 - longitudinal steering traction; 7 - swivel pin; 8 - arm of the swivel pin; 9 - side lever; 10 - transverse thrust

The following requirements are presented to the steering control:

1) ensuring high maneuverability of motor vehicles, in which steep and rapid turns are possible on comparatively limited areas;

2) the ease of control, the validation of the force applied to the steering wheel.

For passenger cars without an amplifier when driving, this force is 50 ... 100 N, and with an amplifier - 10 ... 20 N. For trucks, force on the steering wheel is regulated: 250 ... 500 H - for steering without amplifier; 120 H - for steering with an amplifier;

3) the combustion of controlled wheels with minimal side expansion and sliding when the car is rotated;

4) the accuracy of the tracking action, primarily kinematic, in which any given steering wheel will correspond to a fully defined pre-calculated curvature of rotation;

Introduction

The discipline "Basics of calculating the design and aggregates of cars" is a continuation of the discipline "The design of cars and tractors" and the purpose of the course work is to consolidate the knowledge obtained by the student when studying these disciplines.

Course work is carried out by a student independently using textbooks, tutorials, reference books, guests, custody and other materials (monographs, scientific journals and reports, Internet).

Course operation includes calculation of car control systems: steering (odd student cipher digit) or brake (even figure student cipher). The prototype of the car and the source data is selected by the last two digits of the student's cipher. Wheel clutch coefficient with expensive \u003d 0.9.

Steering in graphics should be: 1) the rotation scheme of the car with the radius and angles of controlled wheels, 2) the circuit of the steering trapezium with the calculated formulas of its parameters, 3) the circuit of the steering trapezium in to determine the dependence of the angles of rotation of the outer and internal controlled wheels graphically , 4) graphs of the dependences of the angles of rotation of external and internal controlled wheels, 5) the overall steering scheme, 6) the scheme for calculating the voltage in the steering bump.

The graphic part of the brake system should contain: 1) a brake mechanism scheme with calculated braking formulas, 2) static characteristics of the braking mechanism, 3) the general scheme of the braking system, 4) a brake crane circuit or the main brake cylinder with a hydraulic amplifier.

The initial data to the traction, dynamic and economic calculation of the car.

Calculation of the car steering

Basic technical parameters

The minimum rotation radius (by the outer wheel).

where L is the base of the car;

HMAX is the maximum angle of rotation of the outdoor controlled wheel.

With a given value of the minimum radius and the car base, the maximum angle of rotation of the outer wheel is determined.

In accordance with the rotation scheme of the car (which must be compiled) determine the maximum angle of rotation of the inner wheel

where M is the distance between the axes of the pussher.

Geometric steering trapezium parameters.

To determine the geometric parameters of the steering trapez, graphic methods are used (it is necessary to make a scheme on scale).

The length of the transverse thrust and side of the trapezium is determined based on the following considerations.

The intersection of the continuing axes of the side levers of the trapezium is at a distance of 0.7L from the front axle, if the trapezium is rear, and at a distance L, if the trapezium is the front (determined by the prototype).

The optimal ratio of the length M of the side lever of the trapezium to the length n of the transverse thrust m \u003d (0.12 ... 0.16) n.

Numerical values \u200b\u200bM and N can be found from the similarity of triangles

where is the resistance from the pivot to the intersection point of the continuation of the axes of the side levers of the steering trapezium.

According to the data obtained, the graphic construction of the steering trapezium is performed. Then, by constructing at an equal angular interval, the position of the inner wheel axle is graphically finding the corresponding positions of the outer wheel and build a graph of the dependence called the actual one. Further, by equation (2.5.2), a theoretical dependence is built. If the maximum difference between theoretical and actual values \u200b\u200bdoes not exceed 1.50 at the maximum angle of rotation of the inner wheel, it is believed that the trapezium is chosen correctly.

The angular gear ratio of the steering is the ratio of the elementary angle of rotation of the steering wheel to the semitum of the elementary angles of rotation of the outer and inner wheels. It is variable and depends on the gear ratios of the steering mechanism URM and the steering drive U Rp

The transfer number of the steering mechanism is the ratio of the elementary angle of rotation of the steering wheel to the elementary angle of rotation of the tower tree. The maximum value must correspond to the neutral position of the steering wheel for passenger cars and the extreme position of the steering wheel for trucks without steering amplifiers.

The transfer number of the steering drive is the attitude of the shoulder of the drive levers. Since the position of the levers in the process of rotation of the steering wheel changes, the transfer number of the steering actuator is variable: UPP \u003d 0.85 ... 2.0.

Power transmission number of steering

where the one is applied to the steering wheel;

The moment of resistance to rotation of controlled wheels.

When designing cars, both minimal (60H) and maximum (120H) force are limited.

According to GOST 21398-75, the force on the site on the concrete surface should not exceed 400 H cars for trucks 700 N.

The moment of resistance to rotation of the controlled wheels is calculated according to the empirical formula:

where -cible adhesion when rotating the wheel in place (\u003d 0.9 ... 1.0);

RS-pressure air in the tire, MPa.

Steering wheel parameters.

The maximum rotation angle of the steering wheel in each side is within 540 ... 10800 (1.5 ... 3 turn).

The diameter of the steering wheel is normalized: for passenger and cargo low load capacity, it is 380 ... 425 mm, and for trucks 440 ... 550 mm.

Effort on the steering wheel for turning on the spot

Pp.k \u003d ms / (), (1.8)

where RPK -Radius steering wheel;

Efficiency of the steering mechanism.

Efficiency of the steering mechanism. Direct efficiency - Provide Efforts from the steering wheel to the Coska

pM \u003d 1 - (MTP1 / MRK) (1.9)

where MTP1 is the rubbing of the steering mechanism, which is shown to the steering wheel.

Reverse efficiency characterizes the transfer of effort from the bump to the steering wheel:

pM \u003d 1 - (MTP2 / MV) (1.10)

where MTP2 is the moment of friction of the steering mechanism given to the shaft of the bustle;

MV.s -Moment on the shaft of the bustle, which was suspended from controlled wheels.

The efficiency of both direct and inverse depend on the design of the steering mechanism and have the following values:

pm \u003d 0.6 ... 0.95; PM \u003d 0.55 ... 0.85

Car control mechanisms - These are mechanisms that are designed to provide the movement of the car in the right direction, and its slowdown or stop if necessary. Control mechanisms include steering and car brake system.

Steering car - this isa combination of mechanisms serving, for rotation of controlled wheels, providescar trafficin the specified direction. Transferring the power of the steering wheel to controlled wheels provides a steering wheel drive. To facilitate the control of the car, power steering amplifiers , machine steering wheel light and comfortable.

1 - transverse thrust; 2 - Lower lever; 3 - swivel pin; 4 - top lever; 5 - longitudinal traction; 6 - power steering; 7 - steering; 8 - steering shaft; 9 - steering wheel.

The principle of operation of the steering

Each controlled wheel is installed on a swivel fist, connected to the front axle by a hundred, which is fixedly attached to the front axle. When rotating the driver of the steering wheel, the force is transmitted by means of thrust and levers on the swivel fists, which turn to a certain angle (sets the driver), changing the direction of the vehicle movement.

Control mechanisms, device

Steering consists of the following mechanisms:

1. Steering mechanism - slowing transmission, transforming the rotation of the steering wheel shaft into rotation of the shaft shaft. This mechanism increases the force applied to the steering wheel The driver makes it easier for his work.
2. Steering wheel drive -the system of thrust and levers in combination with the steering mechanism turn the car.
3. A amplifier of the steering wheel (not on all cars) -it is used to reduce the effort required for the rotation of the steering wheel.

1 - steering wheel; 2 - shaft bearings housing; 3 - Bearing; 4 - steering wheel shaft; 5 - Cardan shaft of the steering; 6 - craving steering trapezium; 7 - tip; 8 - washer; 9 - finger hinge; 10 - crosses of the cardan shaft; 11 - sliding plug; 12 - the tip of the cylinder; 13 - Sealing Ring; 14 - tip nut; 15 - cylinder; 16-stroke with stock; 17 - Sealing Ring; 18 - Ring supporting; 19 - cuff; 20 - Pressing Ring; 21 - nut; 22 - protective coupling; 23 - craving steering trapezium; 24 - Maslenka; 25 - rod tip; 26 - Ring lock; 27 - plug; 28 - Spring; 29 - coaching springs; 30 - Sealing ring; 31 - upper liner; 32 - finger ball; 33 - Lower liner; 34 - lining; 35 - protective coupling; 36 - Rotary fist lever; 37 - Turning fist housing.

Steering device:

1 - the spool body; 2 - Sealing ring; 3 - Rolling Plunger Ring; 4 - cuff; 5 - steering mechanism; 6 - sector; 7 - the plug of the filling hole; 8 - worm; 9 - side cover of crankcase; 10 - cover; 11 - plug plug; 12 - the sleeve is spacer; 13 - needle bearing; 14 - power steering; 15 - craving for steering steering; 16 - shaft of the steering mechanism; 17 - spool; 18 - Spring; 19 - plunger; 20 - cover of the spool housing.

Oil tank. 1 - Tank Corps; 2 - filter; 3 - filter housing; 4 - valve bypass; 5 - cover; 6 - Sapun; 7 - plug of the filler neck; 8 - Ring; 9 - Suction hose.

Pump of an amplifying mechanism. 1 - pump cover; 2 - stator; 3 - rotor; 4 - body; 5 - needle bearing; 6 - spacer; 7 - pulley; 8 - roller; 9 - collector; 10 - distribution disc.

Schematic diagram. 1 - pipelines of temple pressure; 2 - the mechanism of the steering; 3 - pump of an amplifying mechanism; 4 - drain hose; 5 - Oil tank; 6 - Suction hose; 7 - injection hose; 8 - reinforcement mechanism; 9 - hoses.

Car steering KAMAZ

1 is the housing of the control valve of the hydraulic agent; 2 - radiator; 3 - Cardan shaft; 4 - steering column; 5 - Low Pressure Pipeline; 6 - High Pressure Pipeline; 7- tank hydraulic system; 8-pump hydraulic switch; 9 - Cup; 10 - longitudinal traction; 11 - steering mechanism with a hydraulic agent; 12 - corner gearbox.

Car steering mechanism KAMAZ:

1 - jet plunger; 2- control valve housing; 3 - lead gear wheel; 4 - slave gear wheel; 5, 22 and 29-stop rings; 6 - sleeve; 7 and 31 - stubborn colas k ", 8 - sealing ring; 9 and 15 - bandages; 10 - bypass valve; 11 and 28 - covers; 12 - Carter; 13 - Rake piston; 14 - plug; 16 and 20 - nuts; 17 - chute; 18 - ball; 19 - sector; 21 - lock washer; 23 - body; 24 - stubborn bearing; 25 - plunger; 26 - spool; 27- adjusting screw; 30- adjusting washer; 32-toggled shaft sector.

Car steering ZIL;

1 - hydraulic power pump; 2 - pump tank; 3 - low pressure hose; 4 - high pressure hose; 5 column; 6 - contact signal signal; 7 - rotation pointer switch; 8 Cardan hinge; 9 - Cardan shaft; 10 - steering mechanism; 11 - Cup.

Car steering MAZ-5335:

1 - longitudinal steering traction; 2- power steering; 3 - Cup; 4 - steering mechanism; 5- cardan steering drive hinge; 6 - steering shaft; 7 - steering wheel; 8 - transverse steering; 9- left lever transverse steering traction; 10 - swivel lever.