10.31. Corners of installation of forward wheels
Corners of installation of wheels of the car
Corners of installation of forward wheels define geometry of position of the last concerning a suspension bracket of the car and a road covering. Infringement of adjustment of this geometry conducts to decrease in controllability of the car and increase of speed of deterioration of tyres. Into number of corners of installation of forward wheels of the car subject to the control enter disorder, выбег (a corner of a longitudinal inclination of an axis of turn of a wheel), a corner of a cross-section inclination of an axis of turn of a wheel and convergence (Corners of installation of wheels of the car see an illustration). One of parametres — convergence is subject to adjustment only. Designate parametres should be checked on a regular basis for an estimation of degree of deterioration of components of a suspension bracket and a steering drive.
Adjustment of corners of installation of wheels is among demanding special accuracy of measurement of procedures for which qualitative performance presence of special, enough bulky and expensive equipment is necessary. Performance of the given work will charge most correctly to professional mechanics of car-care centre. More low, for the general understanding, definitions of each of under control corners of installation of wheels of the car which knowledge will facilitate dialogue of the owner of the car with the car-care centre personnel are resulted.
As corner of a longitudinal inclination of an axis of turn of a wheel (выбегом) is called the corner of a deviation from a vertical of an axis of turn of a wheel in a plane of the last. If the turn axis is inclined back (the bottom part of an axis is pushed forward), выбег is called as positive, and on the contrary. Adjustment выбега forward wheels is carried out by selection of the remote washers enclosed under pushing bars of a suspension bracket.
As disorder is called the angle of slope of a plane of wheels concerning a vertical. If wheels are inclined by upper edges outside, disorder is called as positive, and on the contrary. The disorder size is measured in degrees. Correctness of adjustment of disorder defines size and position of a stain of contact of protectors with road and allows to compensate changes in geometry of a suspension bracket during fulfilment of turns and at car movement on a rough road covering. On considered models of cars possibility of adjustment of disorder is not provided.
As corner of a cross-section inclination of an axis of turn of a wheel is called the corner between an axis of an inclination of a rotary fist and parallel ДП the car the vertical plane spent through a point of fastening of a wheel.
Thanks to disorder and a corner of a cross-section inclination of an axis of turn of a wheel, a point of a contact of wheels with road settle down more close to an axis of a rotary fist, than the shoulder обкатки »facilitating driving and reducing effect of transfer of blows of wheels about roughness of a covering on a steering is supported so-called«.
As convergence is called the data size to each other forward edges of wheels of the car. Such infringement of parallelism of installation of wheels allows to minimise deterioration of a protector for the account юза at fulfilment of turns. At zero convergence distance between forward edges of wheels to equally distance between their back edges. Normal convergence is resulted in Specifications. Adjustment of convergence of forward wheels is carried out by updating of length of steering draughts at the expense of change of position of their tips. For updating of convergence of back wheels it is provided special adjusting кулачковый a bolt screwed in the internal end of a control lever of a back suspension bracket. Infringement of adjustment of convergence conducts to acceleration of deterioration of protectors of tyres for the account проскальзывания them on a road covering.
Conditions of check of corners of installation of wheels
Check of corners of installation of the car demands presence of a viewing hole or the special measuring lift. At measurement carrying out it is necessary to satisfy following conditions:
- Pressure of air in tyres corresponds to requirements of Specifications;
- Forward wheels are established in rectilinear position;
- The car is not loaded, the fuel tank is completely filled;
- Car suspension brackets strongly прожаты;
- The steering drive is adjusted in the correct image;
- Люфты joints of components of a suspension bracket and a steering drive do not fall outside the limits admissible ranges;
- Depth of a pattern of a protector of tyres of one axis is identical.
All parametres, except convergence, are established by manufacture of the car and adjustment are not subject. If the car has not visited serious failure, corners of installation of wheels should remain during all service life of the car. In the absence of confidence of correctness of definition of parametres not subject to adjustment address for the help to experts.
Convergence can be measured in house conditions in two ways. In the first gauging of distances between forward internal edges of rims of wheels a suitable measuring instrument is made. At use of the second method the special plate is required. Having established a plate to perpendicularly wheel and rotating it, it is possible to reveal a deviation of wheels. The measuring instrument or a plate can be got in specialised shops.
If as a result of check it was found out that convergence requires adjustment, ослабьте counternuts of tips. Turn out a wheel against the stop to the left and precisely count visible number of threads of a carving on the right steering draught. After that turn a wheel against the stop to the right and count visible number of threads on the left draught.
If two numbers coincide, at the subsequent adjustment it will be necessary to turn on or wrap both tips on identical quantity of turns.
If the received results differ from each other, at the subsequent adjustment it is necessary to compensate a difference. After adjustment on both draughts the identical quantity of free threads of a carving should take place.
Having finished adjustment, tighten counternuts, — as draughts rotated, protective covers of the steering mechanism most likely will appear are deformed and it is necessary to weaken collars of their fastening and to make corresponding corrections.