Toe angle UAZ patriot. Checking and adjusting the wheel alignment angles UAZ Patriot

Adjust the wheel alignment on the UAZ 3303, in other things, as on other models 469, 452 "loaf", etc. simply. In addition, unlike passenger cars, the collapse of the UAZ is not done.

Perhaps I’ll start with why it’s impossible to adjust the camber on the UAZ 3303. The fact is that this parameter is embedded in the very design of the machine, namely in the steering knuckle.

If you have no play in the kingpins, and the hub bearings are normally tightened, then everything will be fine with this parameter.

It all started with the fact that the steering wheel began to sluggishly return to its original position, but the worst thing is that the car began to scour the road. At the same time, it could not manifest itself on a flat surface, but if there were bumps or especially rutting.

Instruments

For repairs you will need:

• Key for 30;
• Key on 27;
• Rail.

Wheel alignment adjustment for UAZ 3303

It is important! Adjusting the toe-in of the front wheels UAZ 3303 is carried out at normal tire pressure. The tie rod ends must be in good condition and without play. The adjustment is to ensure that the distance A in the front is less than the distance B by 1.5 - 3.0 mm at the back.

Wheel alignment is usually checked on the inner surface of the tires. But given that tire lateral runout can be significant, toe-in can be adjusted incorrectly. Of course, it is best to adjust at the stand, but before that they always did it themselves. In this case, when adjusting the toe, I take two measurements, one between the tires, the second between the disks. The difference during measurement in the second case should not exceed 1.5 - 2 mm.

Before starting the adjustment, it is necessary to prepare the rod for measurements. To do this, you need a small wooden rail and a caliper. Fix it all as in the photo. Caliper purchased for this inexpensive, plastic. You can do without a caliper, for example, with a ruler, fixing it with rubber bands and putting marks.

Wheel alignment is adjusted by changing the length of the steering rod. To do this, the lock nuts with right and left threads are released in advance and the adjustment fitting is rotated, the length of the rod is changed.

1. Locknut with left-hand thread; 2. Adjusting fitting; 3. Locknut with right-hand thread; 4. Hinge.

The car is installed on a flat area, a measurement is made in front at the middle of the height of the wheels, a point is placed at the points of contact. Then they roll the car over half a circle and take a second measurement from behind. The difference between them will be the value of the convergence of the wheels.

To be sure that the adjusted toe-in of the wheels on the UAZ is correct, it can be repeated at other points.

Tie rod ends must be in good condition and without play.

To ensure the stability and controllability of the car, the front wheels of the car are set at certain angles relative to the elements of the body and suspension. Three parameters are subject to adjustment: convergence, camber angle of the wheel and the angle of the longitudinal inclination of the axis of rotation.

Rice. 1. Pitch angle

The angle of the longitudinal inclination of the axis of rotation (Fig. 1) is the angle between the vertical and the line passing through the centers of rotation of the ball joint and the bearing of the upper support of the guide spring rack, in a plane parallel to the longitudinal axis of the vehicle. To increase the angle of inclination of the axis of rotation, the upper strut support, originally located as shown in photo 1, must be rotated 180 ° relative to the hole in the mudguard cup of the body (photo 2).

In this case, the angle of longitudinal inclination of the axis of rotation will increase by 0°52" (the procedure is described in subsection ).

Camber angle (Fig. 2) - the angle between the plane of rotation of the wheel and the vertical. It is adjustable by turning the top bolt shock absorber strut to knuckle(cm. "Removing the guide spring rack").

Rice. 2. Camber

Toe-in (Fig. 3) - the angle between the plane of rotation of the wheel and the longitudinal axis of the vehicle. Toe-in can also be defined as the difference between the distances between the rim flanges measured at the rear and front of the wheels at the level of their centers. Toe-in is adjusted by rotating the inner tie rod by the flats with the lock nut of the outer tie rod end loosened (see Fig. "Removing the outer tie rod end").

Rice. 3. Wheel alignment

It is recommended to control and adjust the angles of the front wheels at the station Maintenance. Before adjusting, make sure that the tire pressure is correct, the tire tread wear on the left and right wheels is approximately the same, there are no play in the hub bearings and steering elements, the wheels are not deformed.

Checking the wheel alignment angles is mandatory if the suspension units and parts that affect the values ​​of these angles have been replaced or repaired. Due to the fact that the angles of installation of the front wheels are interconnected, first of all, they check and adjust the angle of the longitudinal inclination of the axis of rotation, then the camber, and lastly, the convergence.

Checking and adjusting wheel alignment is necessary to ensure good vehicle stability and handling, as well as uniform tire wear during operation.

Checking and adjusting the wheel alignment angles is carried out on special stands according to the instructions for their operation.

The discrepancy between the actual values ​​measured on the vehicle and the reference values ​​indicated below may be due to wear and deformation of suspension parts, deformation of the body.

Replacing or repairing suspension parts may entail a change in wheel alignment, so checking the wheel alignment after carrying out these works is mandatory.

Wheel alignment is checked by measuring the distance between the middle parts of the sidewalls of the tires. Distance BUT

There should be 0.5-1.5 mm less distance between the wheels in front IN between the rear wheels.

The convergence of the front wheels is regulated by changing the length of the steering link rod.

To adjust the convergence, perform the following operations.

Loosen the lock nuts and rotate the adjusting rod until the wheels are properly aligned, then tighten the lock nuts.
Checking angles maximum turn wheels are carried out on the stand.

The angle of rotation of the right wheel to the right (left wheel to the left) should be within 26-27 °.

Adjust the angle of rotation of the front wheels by turning the stop bolt 1 after loosening the lock nut 2 .

The correct wheel alignment is one of the most important factors that ensure normal handling, stability and stability of the car in straight lines and when cornering. Optimal suspension geometry parameters for each model are set at the design stage. The specified values ​​​​of the wheel alignment angles are subject to change and require periodic adjustment due to natural wear of the components and elements of the chassis or after suspension repairs. Also, the angles should be adjusted when making changes to the car's suspension, for example, with an elevator.

Types of basic car wheel alignment angles

History

How did it all start?
The car was the direct heir to the cart. Remember what it was called at the dawn of motorization? - Horseless wagon. It was the design of the wagon that formed the basis of the first cars.

However, the car differs from the cart in that it is not pulled, but it drives itself. What will happen if such a cart is not pulled, but pushed, and at the same time one wheel runs into a small obstacle? For example, on a pebble or a pothole in the road?
In this case, the system leaves a stable state (rectilinear motion) - the front axle sharp unfolds. This is due to the large running-in shoulder.

How to deal with it? The first thought is to make the break-in shoulder equal to zero with separate steering axes for each wheel. Approximately like this.

Let's say. Then no brick or hole in the road will be able to turn the wheel around its axis of rotation. By the way, in such a design, a longitudinal inclination of the axis of rotation of the wheel (castor) appeared, which at that time was already used in bicycle designs. However, as cars became heavier and their tires wider, this solution began to cause problems. The fact is that it is very difficult for the driver to turn the wheel of such a car in place or at low speed due to the increased mass of the car and the width of its tire profile. There were no power steering at that time, and therefore the designers decided to make the break-in shoulder not zero, but about 25% of the width of the tire profile.

Now, when hitting an obstacle, the turning moment, in comparison with the cart, has decreased by several orders of magnitude, and the force when turning the wheel has become many times less than with zero shoulder, because. now, when turning, the wheel does not turn around the center of the tire contact patch, but rolls, albeit along a small, but radius.

But if there is a small, but still shoulder, each wheel tends to turn outward even when driving on a flat road (without stones and pits). To reduce the turning moment caused by the presence of the break-in shoulder, the wheels are not installed straight, but at an angle. This one is called the corner. wheel alignment. Now the turning moment is compensated by the convergence of the wheels, but the wheels themselves go, as they say, with a plow.

Now the time has come camber. If the wheel “going like a plow” is tilted outward, then due to the elastic deformation of the tire, the wheel, in the contact patch with the road, will take the form of a strongly truncated cone that will roll in an arc. Now, in fact, we do not have cylinder wheels “going like a plow”, but two truncated cones. And due to the fact that these "cones" have both convergence and collapse, their treadmills are directed directly.

But now, after turning the steering wheel, the wheels “do not want” to return to the straight position, and in general, you have to “catch” this most direct position all the time. A positive castor helps a little here. What to do?

This problem was solved simply - tilted the axis of rotation of the wheel in the transverse plane(angle β). Now when you turn the wheel, the front of the car will rise. The steering wheel will become a little heavier, but when the car is moving, the wheels will tend to take a straight position, as they say, automatically.

Over time, the speed of cars increased and it took dynamic stabilization- so that the wheel, at speed, returns to its original position if for some reason it deviates. For this, we entered longitudinal angle tilt axis of rotation - caster. (piano wheel principle)
In dynamics, the wheel tends to take the most stable position, which is behind the axle.

Now, when turning, the lateral reactions of the road applied behind (thanks to the caster!) Try to return the wheel to its place.
Moreover, if the car is subjected to a lateral force that is not associated with a turn (for example, you are driving on a slope or with a crosswind), then the caster provides with an accidentally released steering wheel smooth turn machine "downhill" or "downwind" and prevents it from tipping over.

Now about the same, but more formally:

Camber- this is the angle formed by the median plane of the wheel and the vertical passing through the point of intersection of the median plane of the wheel and the supporting surface. Distinguish between positive and negative camber:
positive (+) - when the top of the wheel is tilted outward (away from the car body)
negative (-)- when the top of the wheel is tilted inward (towards the car body)

Structurally camber formed by the position of the hub assembly and provides maximum contact area tires with the road. In the case of a double lever independent suspension the position of the hub is determined by the upper and lower wishbones. In a MacPherson-type suspension, the formation of the camber angle is affected by lower arm and shock absorber. The deviation of the camber angle from the norm affects the car as follows:

+ good car stability in turns
- Decreased wheel traction during straight driving
- increased wear inside tires

Too large positive angle:
+ good road grip
- Decreased cornering stability
- increased wear on the outer side of the tire

For UAZ vehicles, the camber angle is set rigidly and is:
for UAZ-452 And UAZ-469: 1°30+-15"
for UAZ Patriot and UAZ Hunter with axles Spicer: 1°

Wheel alignment (English toe)- the angle between the longitudinal axis of the car and the plane of rotation of the wheel. It can also be defined as the difference in distance between the front and rear sides of the wheel rims (in the figure this is the value A minus B). Thus, convergence can be measured in degrees or millimeters.

Distinguish between total and individual convergence. Individual convergence is calculated separately for each wheel. This is the deviation of the plane of its rotation from the longitudinal axis of symmetry of the car. The total toe-in is calculated as the sum of the individual toe-in angles of the left and right wheels of the same axle. Similarly, the total convergence in millimeters is determined.
With a positive toe-in, the wheels are mutually turned inward in the direction of travel, with a negative value (eng. toe-out) - outward.

The deviation of the toe angle values ​​from the norm affects the car as follows:

Too big negative angle:
- keeping the trajectory of the movement worsens
- Increased tire wear on the inside
- sharp reaction of the car to the steering

Too large positive angle:
- keeping the trajectory of the movement worsens
- increased tire wear on the outside

Wheel alignment on UAZ is adjustable and is for cars (B-A)
UAZ-452, UAZ-469: 1.5-3.0mm. (23"+-0.8")
UAZ Patriot, UAZ Hunter with Spicer type bridges: 0.5-1.5mm(from 0°3"04" to 0°9"12")

The transverse angle of inclination of the axis of rotation of the wheel

Lateral angle of inclination of the axis of rotation (eng. KPI)- the angle between the axis of rotation of the wheel and the perpendicular to the supporting surface. Due to this parameter, when the steered wheels are turned, the car body rises, as a result of which forces arise that tend to return the wheel to a straight position. Thus, KPI has a significant impact on the stability and stability of the vehicle in a straight line. The difference in the values ​​of the angles of the transverse inclination of the right and left axles can lead to the withdrawal of the vehicle to the side with a large inclination. This effect can also manifest itself if the other wheel alignment angles correspond to the normal values.

For UAZ vehicles, the angle of transverse inclination is rigidly set and is:
UAZ-452, UAZ-469B: 5°30"+- 0°30"
UAZ-469 from portal bridges: 8°
UAZ Patriot, UAZ Hunter with Spicer type bridges: 8°

Pitch Angle

Longitudinal angle of inclination of the axis of rotation (English caster)- the angle between the axis of rotation of the wheel and the perpendicular to the supporting surface in the longitudinal plane of the vehicle. Distinguish between positive and negative angles of longitudinal inclination of the axis of rotation of the wheel.

Positive caster contributes to the emergence of additional dynamic stabilization vehicle while driving at medium and high speeds. This worsens the steering at low speed.

The angle of longitudinal inclination of the king pin for UAZ vehicles is set rigidly.
for UAZ-452, UAZ-469, UAZ-469B: 3°+-0°30"
for UAZ Patriot, UAZ Hunter with Spicer type bridges: 5 ° -1°

In addition to the above parameters, another characteristic is of great importance for the front axle - running shoulder. This is the distance between the point formed by the intersection of the axis of symmetry of the wheel and the ground, and the point of intersection of the line of the transverse inclination of the axis of rotation and the ground. The run-in shoulder is positive if the point of intersection of the surface and the axis of rotation of the wheel lie to the right of the axis of symmetry of the wheel (zero shoulder), and negative if it is located to the left of it. If these points coincide, then the running-in shoulder is zero.

This parameter affects the stabilization and steering of the wheel. The optimal value for modern cars is zero or positive run-in shoulder. The sign of the running-in shoulder is determined by the camber, the transverse inclination of the axis of rotation of the wheel and the offset of the rim.

Automakers do not recommend installing wheel disks with a non-standard departure, because this may result in changing the set running-in shoulder to a negative value. This can seriously affect the stability and handling of the vehicle.

Partially used materials from the article by Alexei Trebunsky