18.1.2. Angles of installation of forward wheels

Angles of installation of wheels

t – corner of a longitudinal inclination of an axis of turn;
M – the center of a wheel;
– corner of disorder of wheels;
– corner of a cross inclination of an axis of turn;
M – the center of a wheel;

B-and – a convergence of forward wheels;
And yes B – distance (mm) between wheels in front and behind;
S – corner of a convergence of forward wheels;
S – track.

For ensuring good stability and controllability of the car forward wheels are established under certain corners concerning elements of a body and a suspension bracket. Regulate three corners: corner of a longitudinal inclination of an axis of turn, corner of disorder and corner of a convergence of wheels. Distinguish still a corner of a cross inclination of an axis of turn, but it is set by geometry of a rotary fist and is not regulated.

Corner of a longitudinal inclination of an axis – a corner between a vertical and a projection of the line passing through the centers of spherical support on the plane parallel to a longitudinal axis of the car. It promotes stabilization of the operated wheels in the direction of the rectilinear movement. This corner is regulated by change of quantity of adjusting washers on bolts of fastening of an axis of the top lever. During removal of washers from a back bolt or at addition it increases by forward, at the return shift – decreases. Corner size deviation symptoms from norm: withdrawal of the car aside at the movement, different efforts on a steering wheel in the left and right turns, unilateral wear of a protector of tires.

Corner of disorder of wheels – a corner between the plane of rotation of a wheel in situation "directly" and a vertical. It promotes the correct provision of the sliding wheel during the work of a suspension bracket. The corner is regulated by change of quantity of washers on bolts of fastening of an axis of the top lever. For reduction of disorder remove equal quantity of washers (packages of washers of equal thickness) from both bolts, for increase – add. At the plant on each bolt put on one washer 3 mm thick, other washers – 0,75 mm. If necessary delete thick washers. If all washers are removed, but it is not possible to adjust corners, check a condition of rubber-metal hinges and a cross-piece of a suspension bracket: the distance between external surfaces of arms of a cross-piece near bolts of fastening of axes of the top levers has to be 736±1,5 mm. If it not so, replace a cross-piece, check body geometry for HUNDRED. At a strong deviation of disorder from norm withdrawal of the car from the rectilinear movement and unilateral wear of a protector is possible.

Convergence of wheels – a corner between the plane of rotation of a wheel and a longitudinal axis of the car. Sometimes this corner is measured as a difference of distances And yes B (see the drawing). The convergence promotes the correct provision of the operated wheels at various speeds of the movement and angles of rotation of the car. The corner is regulated by change of length of side steering drafts rotation of adjusting couplings at the weakened coupling collars. Before adjustment the bipod of the steering mechanism is established in average situation (spokes of a steering wheel stand horizontally). Convergence deviation signs from norm: strong sawtooth wear of tires (even at small deviations), squeal of tires in turn, the increased fuel consumption because of the big resistance to swing of forward wheels (выбег the car there is much less put).

Control and adjustment of angles of installation of forward wheels is recommended to be carried out at service station. The car is installed on the horizontal platform and loaded according to recommendations of manufacturer. (Check and adjustment of corners on not loaded car are admissible, but yield less exact results.) Before it it is necessary to be convinced that pressure in tires meets standard, wear of a protector on the left and right wheel is approximately identical, there is no side play in bearings and steering, rims are not deformed (a radial beating – no more than 0,7 mm, axial – no more than 1 mm).

Check of angles of installation of wheels is obligatory if changed or repaired the suspension bracket details influencing these corners. First of all check and regulate a corner of a longitudinal inclination of an axis of turn, then a corner of disorder and in the last turn – a convergence of wheels.

At the rolled car in the equipped state and with the payload of 320 kgfs (4 persons in salon and 40 kgfs of freight in a luggage carrier) the angles of installation of wheels have to be in the following limits:

Corner of a longitudinal inclination of an axis of turn, t

3o30 '±30'
Corner of disorder of wheels,
0o30 '±20'
Convergence of forward wheels
(3±1) mm

Change of corners of disorder and longitudinal inclination of an axis of turn at change of quantity of washers 0,75 mm thick on bolts of fastening of an axis of the top lever

Quantity of the added or remote washers

Corner of disorder of wheels ()
Corner of a longitudinal inclination of an axis of turn (t)
Forward bolt
Back bolt
1
1
(8'42")
0
– 1 – 1
– (8'42")
0
1
0
– (7'30")
(20'24")
– 1
0
(7'30")
– (20'24")
0
1
(15'18")
– (25'18")
0
– 1
– (15'18")
(24'18")
– 1
1
(27'30")
– (43'18")
1
– 1
– (21'36")
(40')