5.5.1. Adjusting parametres of wheels and their adjustment
In designing of cars working out of safe systems of a steering and suspension brackets is paramount. Each component should be strong enough to sustain and absorb maximum loads. The steering, and also forward and back suspension brackets should function geometrically with a car body. Systems of a steering and a suspension bracket demand, that forward wheels were self-coming back and that couplings of a rotating wheel and a road covering were provided with insignificant force of driving with the least effort and the greatest comfort.
Full check of adjusting corners of wheels should include measurement of a convergence and disorder of back wheels.
Adjustment of adjusting corners of four wheels guarantees that all wheels will slide strictly in one direction. When adjusting corners of wheels are adjusted, the economy of the expense of fuel and a run resource reach the maximum size, controllability of the car improves.
Fig. 5.66. A convergence of wheels
As convergence is called turn of wheels inside; return convergence of wheels is a turn of wheels outside from the central line (fig. 5.66
). The convergence of wheels provides parallel planes of rotation of wheels.
The convergence serves for neutralisation of small deviations of the wheel which are taking place at movement of the car forward. The established size of a corner of a convergence is an installation of such corner at which it is reached 0 ° degrees between planes of rotation of forward wheels and the central line of the moving car (a convergence is absent).
The wrong convergence or return convergence of wheels leads to premature deterioration and increase in the expense of fuel. Separate components of a steering and a suspension bracket wear out depending on car run, the additional convergence is necessary for deterioration alignment. Always correct a convergence corner in last turn.
Fig. 5.67. An axis Angle of slope шкворня
Axis angle of slope шкворня
is the inclination of the highest point of an axis rotary шкворня
forward or back from a vertical at the sight of the car sideways (fig. 5.67
The inclination is positive and forward — negative back. The axis angle of slope шкворня influences the control of a direction of a steering, but does not influence deterioration of tyres. Weak (having to a deposit) springs or the overloaded car influence an axis angle of slope шкворня. One wheel with the big positive inclination of an axis шкворня pulls to the car centre. It becomes the reason of movement or an inclination of the car towards a wheel with a smaller positive angle of slope of an axis шкворня. The corner is measured in degrees, but not regulated.
Fig. 5.68. A corner of disorder of a forward wheel
The corner of disorder of a forward wheel is an inclination of the top point of the tyre from a vertical at the sight of the car in front (fig. 5.68
). When the wheel is inclined outside, disorder of a wheel the positive. When the wheel is inclined inside, disorder negative. The disorder corner is measured in degrees from a vertical. Disorder influences the control of a direction and on deterioration of tyres.
If at the car the big positive disorder of a wheel, is exposed to deterioration an external part of a protector of tyres. If at the car the big negative disorder of a wheel, is exposed to deterioration an internal part of a protector of tyres. The disorder corner is measured in degrees and not regulated.
Inclination of an axis rotary шкворня is the inclination of the top point of a rotary fist from a vertical. Measure a corner from a vertical to a line through the centre of a rack and the bottom spherical hinge at the sight of the car in front.
The inclination of an axis rotary шкворня helps the car to move directly and promotes returning of wheels to their former place. The inclination of an axis rotary шкворня on front-wheel cars should be negative.
The corner of a cross-section inclination of an axis of a rotary rack is measured from a corner of disorder of a forward wheel to a line passing through the centre of a rack and the bottom spherical hinge at the sight of the car in front. The corner is calculated in degrees. Рейкой for measurement and adjustment of adjusting corners of wheels it is impossible to measure this corner completely.
For definition of this corner subtract a corner of negative disorder or add positive disorder to an inclination of an axis rotary шкворня.
The shoulder обкатки is a distance between a point of intersection of the continued axis шкворня a rotary pin with road and the centre of a basic surface of the tyre. The shoulder обкатки is put in a car design.
Displacement is a distance in which one forward nave with the bearing in gathering can be displaced back from other nave with the bearing in gathering back. Displacement back basically occurs because of road failure or car collision.
The angle of rotation is a corner of each forward wheel to a vertical at car turn.
Adjustment of a convergence of forward wheels
Fig. 5.69. Directions of rotation of steering draught at convergence adjustment
Remove collars from both protective covers of the mechanism of steering transfer. Ослабьте the
left and right counternuts of tips of steering draughts. Rotate the right and left steering draughts for adjustment of adjusting corners of forward wheels (fig. 5.69
The length of the left and right steering draughts should be identical.
Nominal corner of a convergence of forward wheels 10 °.
At turn of steering draught on one turn the convergence size changes on 1,5 mm.
Tighten counternuts of tips of steering draughts the moment 45 Н·м.
Establish collars of fastening of protective covers of the mechanism of steering transfer.
Check of disorder and axis angle of slope шкворня forward wheels
Disorder and axis inclination шкворня forward wheels are not regulated. Before measurement of a corner of disorder or an axis angle of slope шкворня three times shake for a bumper of the car for prevention of wrong measurement. If the size of measurement of corners of disorder or an inclination шкворня forward wheels differs from the demanded size, define a site of malfunction and replace or repair all damaged, weakened, bent, deformed or worn out details of a suspension bracket. If malfunction is connected with a body, repair a body.
Check of disorder of back wheels
Disorder of back wheels is not regulated. If the corner of disorder of back wheels differs from the demanded size, define a cause of defect and eliminate it. If the damaged, weakened, bent, deformed or worn out parts of a suspension bracket are found out, it is necessary to repair or replace them. If malfunction is connected with a body, repair a body.
Check of a convergence of back wheels
The convergence of back wheels is not regulated. If the size of a corner of a convergence differs from the demanded size, check up a back axis in gathering and a wheel axis on the car on absence of damages.