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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 provision of the last concerning a car and paving suspension bracket. Violation of adjustment of this geometry conducts to decrease in controllability of the car and increase of speed of wear of tires. Into number of subjects to control of corners of installation of forward wheels of the car 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 (see an illustration Corners of installation of wheels of the car). One of parameters — convergence is subject to adjustment only. Designate parameters should be checked on a regular basis for an assessment of degree of wear 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 high-quality performance existence of special, rather bulky and expensive equipment is necessary. It will be most correct to charge performance of this work to professional mechanics of car-care center. Below, for the general understanding, definitions of each of under control corners of installation of wheels of the car which knowledge will facilitate communication of the owner of the car with the car-care center personnel are given.
(Vybegy) the deviation corner from a vertical of an axis of turn of a wheel in the plane of the last is called as a corner of a longitudinal inclination of an axis of turn of a wheel. If the axis of turn is inclined back (the lower 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.
The tilt angle of the plane of wheels concerning a vertical is called as disorder. If wheels are inclined by the upper edges outside, disorder is called as positive, and on the contrary. The size of disorder is measured in degrees. Correctness of adjustment of disorder defines size and the provision of a spot of contact of protectors with the road and allows to compensate changes in suspension bracket geometry during commission of turns and at car movement on a rough paving. On considered models of cars possibility of adjustment of disorder is not provided.
The corner between an axis of an inclination of a rotary fist and parallel DP of the car the vertical plane which has been carried out through a point of fastening of a wheel is called as a corner of a cross-section inclination of an axis of turn 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 the road settle down closer to an axis of a rotary fist, than «the running in shoulder» facilitating driving and reducing effect of transfer of blows of wheels about roughness of a covering on a steering is supported so-called.
The data size to each other forward edges of wheels of the car is called as convergence. Such violation of parallelism of installation of wheels allows to minimize wear of a protector for the account юза at commission of turns. At zero convergence distance between forward edges of wheels equally to distance between their back edges. Normal convergence is given in Specifications. Adjustment of convergence of forward wheels is carried out by adjustment of length of steering drafts at the expense of change of provision of their tips. For correction of convergence of back wheels the special adjusting kulachkovy bolt screwed in the internal end of a control lever of a back suspension bracket is provided. Violation of adjustment of convergence conducts to acceleration of wear of protectors of tires at the expense of a proskalzyvaniye them on a paving.
Conditions of check of corners of installation of wheels
Check of corners of installation of the car demands existence of a viewing hole or the special measuring lift. At carrying out measurement it is necessary to satisfy the following conditions:
- Pressure of air in tires corresponds to requirements of Specifications;
- Forward wheels are established in rectilinear situation;
- The car is not loaded, the fuel tank is completely filled;
- Suspension brackets of the car strongly прожаты;
- The steering drive correctly is adjusted;
- Lyufta 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 tires of one axis is identical.
All parameters, except convergence, are established by production of the car and adjustment are not subject. If the car did not visit serious failure, corners of installation of wheels should remain during all service life of the car. In the absence of confidence of correctness of determination of parameters not subject to adjustment address for the help to experts.
Convergence can be measured in house conditions in two ways. In the first measurement of distances between forward internal edges of rims of wheels a suitable measuring instrument is made. When using the second method the special plate is required. Having established a plate perpendicular to a wheel and rotating it, it is possible to reveal a deviation of wheels. The measuring instrument or a plate can be got in specialized shops.
If as a result of check it became clear that convergence needs adjustment, weaken lock-nuts of tips. Turn out a wheel against the stop to the left and precisely count visible number of strings of a carving on the right steering draft. After that turn a wheel against the stop to the right and count visible number of threads on the left draft.
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 drafts the identical quantity of free strings of a carving should take place.
Having finished adjustment, tighten lock-nuts — as drafts 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 the corresponding corrections.