A kind of McPherson strut camber angle two dimension Deviation Analysis Method
Technical field
The present invention relates to automotive suspension technical field more particularly to a kind of McPherson strut camber angle two dimension variance analyses
Method.
Background technique
McPherson strut is one of widest car front suspension extension of the world today, as shown in Figure 1, MacPherson type is outstanding
Frame is made of damper 1, upper suspension arm 2, lower control arm 4, subframe 3 and brake assembly 5, and most vehicles can also add
Stabilizer bar.McPherson strut structure is simple, so its light weight, fast response time, and in a lower shake-changing arm and pillar
Geometry under can adjust automatically camber angle, allow its can when excessively curved adaptive road surface, allow tire contact area most
Bigization, to be widely applied on driving car before light-duty vehicle, car are especially preposition.But since it is configured to
Straight barrel type lacks barrier force to the impact of left and right directions, and anti-brake, which is nodded, to be acted on poor, and suspension stiffness is weaker, and stability is poor, turns
It is curved to roll obviously.
Suspension camber angle refers to the angle between medium plane of wheel 6 and road plane vertical line 7, is defined as: by vehicle front
It sees tire centerline and vertical line straight line angulation, is positive to outside vehicle body, is negative to interior of body, the difference of camber angle can change
Contact point and the point of application for becoming tire and ground directly affect the road holding and abrasion situation of tire, to influence the row of automobile
Into direction, if the camber angle of left and right wheels is unequal, the problem of will appear running car sideslip.Therefore, to the inclined of camber angle
Difference is analyzed, it is ensured that vehicle suspension system successively assembles camber angle qualification rate and reaches requirement, has certain practical significance.
The method that the existing deviation to camber angle is analyzed be usually by three-dimensional deviation software modeling and analysis, this
Kind method is not only at high cost, modeling period is long, but also inefficiency, and departing from three-dimensional artificial software, which will be unable to be unfolded.
Summary of the invention
The purpose of the present invention is to provide a kind of McPherson strut camber angle two dimension Deviation Analysis Methods, can not have
In the case where three-dimensional artificial software, quickly and efficiently the deviation of suspension camber angle is analyzed, to solve vehicle camber angle
It is disposable to cross the low problem of line rate.
To achieve the above object, the present invention adopts the following technical scheme:
A kind of McPherson strut camber angle two dimension Deviation Analysis Method method, successively the following steps are included:
(1) suspension camber angle measurement model is created;
(2) according to the assembly relation of suspension, each part is defined in the rigging position in space;
(3) interspace analytic geometry method is utilized, derives the calculation formula of rear-wheel camber angle, using the calculation formula, and
Rigging position according to part in space, the components deviation that will affect flare angular displacement are divided into two parts, rule of thumb select
The tolerance of this two parts components;
(4) angular displacement of suspension flare is calculated:
The tolerance of each components is inputted into suspension camber angle calculation formula, obtains suspension camber angle, and carry out to camber angle
Analysis, if being unsatisfactory for demand, is adjusted the tolerance of a certain chain link, until camber angle meets the requirements.
Preferably, in the step (1), when creating suspension camber angle measurement model, with the center of vehicle left rear side wheel
Establish rectangular coordinate system in space for origin, wherein vehicle forward direction be x-axis forward direction, vertically upward direction be y-axis just
To the direction from origin to copilot is the forward direction of z-axis, and the center for defining left rear side wheel is E point, main pin axis and axletree
Intersection point of the line on rearview is D point.
Preferably, in the step (2), each part is defined in the rigging position in space, is defined according to following principle:
Part has 6 freedom degrees, i.e. translation and 3 rotations around reference axis along 3 reference axis in space, uses base first
Quasi- A constrains three degree of freedom, then plus a benchmark B constrain it 2 freedom degrees, the benchmark C that has another one constrains one degree of freedom,
That part just has a completely specified position in space, generallys use 6 freedom degrees that 6 obligatory points carry out limit feature,
That is 3-2-1 principle.
Preferably, in the step (3), using interspace analytic geometry method, the calculation formula of rear-wheel camber angle is derived
Are as follows:Wherein, yEIndicate E point y to coordinate value, yDIndicate D point y to coordinate value, zEIndicate E
Point z to coordinate value, zDIndicate D point z to coordinate value;It can be seen that by the calculation formula, camber angle γ exists with E point, D point
Y-axis is related with the coordinate value of z-axis, when E point coordinate value determine after, to rear-wheel camber angle have an impact be only D point coordinate value,
D point is that vehicle body is installed on the intersection point of main pin axis and wheel axis on rearview, with subframe installation point on vehicle body, subframe
Hub bracket installation point, the tolerance of hub bracket upper swing arm installation point are related on point and swing arm installation point, swing arm;
According to the manufacture of rear-wheel camber angle calculation formula and the suspension and assembly technology, the zero of flare angular displacement will affect
Part is divided into two parts, first is that due to vehicle body, subframe, swing arm and brake assembly manufacture and assembly caused by Y-direction deviation, this
A part of deviation includes subframe installation point tolerance, foreside bodywork installation point tolerance, rear portion body mounts tolerance, upper swing arm peace
Decorate tolerance, lower swing arm installation point tolerance and brake assembly installation point tolerance;Second is that due to the system of brake disc and three generations's bearing
Total run-out deviation caused by making and assembling, this part of deviation includes brake disc disk run-out tolerance, brake disc disk verticality
Run-out tolerance between tolerance and three generations's bearing and brake disc, brake holder beam matching face;Then rule of thumb select above-mentioned public affairs
Difference.
Preferably, the step (4) the following steps are included:
1. calculating camber angle γ caused by Y-direction deviation1,Wherein, Y1 indicates the tolerance of Y-direction deviation,
It is calculated using the normal distribution curve of each tolerance of composition Y-direction deviation, H1Indicate E point and D point in the difference in height of z-axis;
2. calculating camber angle γ caused by total run-out deviation2,Wherein, X2Indicate total run-out deviation
Tolerance is calculated, H using the normal distribution curve of each tolerance of composition total run-out deviation2Indicate E point and D point in the height of y-axis
Difference;
3. rear suspension camber angle γ is calculated,
4. adjustment causes each zero of flare angular displacement when calculated rear suspension flare angular displacement γ=± 0.5 °
The deviation of part, until suspension flare angular displacement γ=± 0.59 °.
The present invention passes through suspension camber angle measurement model and each part in the rigging position in space, to derive outside rear-wheel
Dip countion formula, the influence using the calculation formula analysis part manufacturing and assembling deviation to suspension flare angular displacement, effectively
Ground solves the problems, such as that the disposable line rate of crossing of camber angle is low, without three deviation softwares, has at low cost and high-efficient
The advantages of.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of McPherson rear suspension of the present invention;
Fig. 2 is camber angle measurement model figure of the present invention.
Specific embodiment
Technical solution of the present invention is clearly and completely described below in conjunction with attached drawing, it is clear that described embodiment
Only section Example of the invention, instead of all the embodiments.Based on the embodiments of the present invention, the common skill in this field
Art personnel other all embodiments obtained without making creative work, belong to protection model of the invention
It encloses.
The present invention is when calculating, it is assumed that all to participate in the matched Tolerance assignment rule followed normal distribution regularity of distribution, participation
The tolerance matched from input drawing, the unknown drawing in part and data parameter tolerance by assuming that, participate in the part of calculating
Based on rigidity it is assumed that not considering other systems or accidental error in addition to the manufacturing tolerance of part itself, not considering frock clamp
Abrasion and deformation, do not consider assembly force, thermal expansion, gravity, do not consider that gravity influences.
Based on situation assumed above, the invention discloses a kind of McPherson strut camber angle two dimension Deviation Analysis Method,
Successively the following steps are included:
(1) suspension camber angle measurement model is created;
As shown in Fig. 2, establishing rectangular coordinate system in space as origin using the center of vehicle left rear side wheel, wherein before vehicle
It is the forward direction of x-axis into direction, vertically upward direction is the forward direction of y-axis, and the direction from origin to copilot is the forward direction of z-axis,
The center for defining left rear side wheel is E point, and the intersection point of main pin axis and wheel axis on rearview is D point.
(2) according to the assembly relation of suspension, each part is defined in the rigging position in space;
Part has 6 freedom degrees in space, i.e., base is used in 3 translations and 3 rotations around reference axis along reference axis first
Quasi- m constrains three degree of freedom, then plus a benchmark n constrain it 2 freedom degrees, the benchmark p that has another one constrains one degree of freedom,
That part just has a completely specified position in space, generallys use 6 freedom degrees that 6 obligatory points carry out limit feature,
That is 3-2-1 principle.
(3) interspace analytic geometry method is utilized, derives rear-wheel camber angle calculation formula, using the calculation formula, and root
Rigging position according to part in space, the part that will affect flare angular displacement are divided into two parts, rule of thumb select this two parts
The tolerance of part;Using interspace analytic geometry method, rear-wheel camber angle calculation formula is derived are as follows:Its
In, yEIndicate E point y to coordinate value, yDIndicate D point y to coordinate value, zEIndicate E point z to coordinate value, zDIt indicates
D point z to coordinate value;It can be seen that by the calculation formula, camber angle γ and E point, D point are related in the coordinate value of y-axis and z-axis,
After E point coordinate value determines, to the coordinate value for the only D point that rear-wheel camber angle has an impact, D point is main pin axis and axletree
On intersection point of the line on rearview, with subframe installation point on vehicle body, subframe in body mounts and swing arm installation point, swing arm
Hub bracket installation point, the tolerance of hub bracket upper swing arm installation point are related.
According to the manufacture of rear-wheel camber angle calculation formula and the rear suspension and assembly technology, flare angular displacement will affect
Part is divided into two parts, first is that due to vehicle body, subframe, swing arm and brake assembly manufacture and assembly caused by Y-direction deviation,
This part of deviation includes subframe installation point tolerance, foreside bodywork installation point tolerance, rear portion body mounts tolerance, upper swing arm
Installation point tolerance, lower swing arm installation point tolerance and brake assembly installation point tolerance;Second is that due to brake disc and three generations's bearing
Manufacture and total run-out deviation caused by assembling, this part of deviation include that brake disc disk run-out tolerance, brake disc disk are vertical
Spend the run-out tolerance between tolerance and three generations's bearing and brake disc, brake holder beam matching face;It then rule of thumb selects above-mentioned
Tolerance value.
(4) angular displacement of suspension flare is calculated:
Since probabilistic method can make each group obtain looser tolerance value at chain link, saved in the case where meeting assembling function demand
Cost, therefore the angular displacement of suspension flare, probabilistic method calculation formula are calculated using probabilistic method in the present invention are as follows:
Wherein, ynThe tolerance for indicating each chain link, by step (3) it is found that influence the angular displacement of rear-wheel flare because being known as two
Part, therefore deviation, i.e. y are calculated by two chain links1Indicate vehicle body, subframe, swing arm and the manufacture of brake assembly and assembly
Caused Y-direction deviation, y2Total run-out deviation caused by indicating the manufacture of brake disc and three generations's bearing and assembling, specific calculating process
It is as follows:
1. calculating camber angle γ caused by Y-direction deviation1,Wherein, Y1 indicates the tolerance of Y-direction deviation,
It is calculated using the normal distribution curve of each tolerance of composition Y-direction deviation, H1Indicate E point and D point in the difference in height of z-axis;
2. calculating camber angle γ caused by total run-out deviation2,Wherein, X2Indicate total run-out deviation
Tolerance is calculated, H using the normal distribution curve of each tolerance of composition total run-out deviation2Indicate E point and D point in the height of y-axis
Difference;
3. rear suspension camber angle γ is calculated,
4. adjustment causes each zero of flare angular displacement when calculated rear suspension flare angular displacement γ=± 0.5 °
The deviation of part, until rear suspension flare angular displacement γ=± 0.59 °.
Embodiment one
Technical solution of the present invention is described further by taking H arm multi-connecting-rod separated suspension structure as an example below.
The tolerance value difference of Y-direction deviation and total run-out deviation in step (3) is as shown in Table 1 and Table 2:
Table 1
Table 2
The tolerance Y of Y-direction deviation can be calculated according to table 11The height difference H of=3.64mm, E point and D point in z-axis1=
389.63mm, this difference in height are determined according to the assembling structure of H arm multi-connecting-rod separated suspension structure, are available data, then
The tolerance X of total run-out deviation can be calculated according to table 22The height difference H of=0.0286mm, E point and D point in y-axis2=
79.57mm, this difference in height are determined according to the assembling structure of H arm multi-connecting-rod separated suspension structure, are available data, then
Then rear suspension camber angleSo
This camber angle is analyzed afterwards, when target design tolerance is ± 0.5 °, above-mentioned rear suspension camber angle γ meets percentage
99.49%, but 99.9% theoretical design requirements are unsatisfactory for, to meet, then adjustment causes each of suspension flare angular displacement
The deviation of components;When target design tolerance is ± 0.59 °, then above-mentioned suspension camber angle γ meets the reason of percentage 99.9%
By design requirement.
The present invention quickly and efficiently can carry out the deviation of suspension camber angle in the case where no three-dimensional artificial software
Analysis has the advantages that at low cost and high-efficient to solve the problems, such as that the disposable line rate of crossing of vehicle camber angle is low.