The parameters of the steering mechanism of a model with rack and pinion steering mechanism are as follows: the wheel base L is 2344 m m, the distance K between the main pins is 1285 mm, the length m of the rack is 635 mm, the allowable length [S] of the rack is 64 mm, the installation distance E of the rack is 96 mm, the length r of the trapezoid arm is 126 mm, and the trapezoid base angle θ 0 is 69 °. Using C + + Builder software programming, draw four kinds of error curves of the half steering process of the rack and pinion steering mechanism (that is, the process of left or right steering of the car) as shown in Figure 4.
The steering wheel angle error curve is similar to the steering toe error curve, and the steering center error curve I is similar to the steering center error curve II. Among them: the steering toe in error can directly show the intersection of the left and right steering wheel corners, and can also be combined with the pre imposed toe in angle of the vehicle for comprehensive analysis; the steering center error I directly represents the deviation between the steering center of the vehicle and the axis of the rear wheel, while when the left steering wheel angle is 0 °, the value of the steering center error II is infinite, so it is impossible to analyze the error within the range of the angle close to 0 °. Therefore, for the rack and pinion steering mechanism, the steering toe in error and steering center error I can better express the steering mechanism error.
1) Among the four kinds of errors of rack and pinion steering mechanism, the curve of steering wheel angle error is similar to that of steering toe in error, steering toe in error can more intuitively reflect the intersection characteristics of left and right steering wheel angle; the curve of steering center error I is similar to that of steering center error II, and steering center error I can intuitively express the deviation of steering center and rear wheel axis. Therefore, it can be selected according to the actual situation.
2) Among the parameters of the mechanism, the most significant one is the trapezoid arm length, and the most significant one is the rack installation distance.