**Auto hinge** design is an important design work, whether directly related to the normal door open in the hinge design, the hinge centerline location and center distance is an important hinge design hard point.

Hinge axis generally designed to have a inclination angle and caster angle. Inclination refers to the hinge axis at x = 0 plane of projection and the z-axis between the angle of inclination is generally from 0 to 4 degrees; after the angle refers to the hinge axis in the y = 0 plane of projection and the angle between the z-axis, generally from 0 to 2 ° inclination angle and caster angle are intended to enable open access self-closing door force, there are also individual auto hinge with a first inclination, but in general no camber.

Auto hinge axis hinge axis to determine the design of the first direction along the body size range (X1, X2), and optional in this context a value Xm, the axis limits and the x-axis perpendicular to the plane x = Xm, the in the x = Xm plane to determine the status of the hinge axis tilt: first find the x = Xm, respectively, inside and outside the plate surface plane and the intersection line C1 and C2, C1 and C2, and find the corresponding y-coordinate of the limit position of Ymin (inner plate projection line far left) 、Ymax (rightmost outer plate projection line); at x = Xm plane by entering the straight line equation y = B, B Ymin to Ymax in between to generate a z-axis parallel to the axis of Z1Z2; determine the center of the hinge axis z-coordinates of points: within the board by the board under the lower border of the border or outside the calculated average position coordinates z = C, and according to it on the line y = B find the point O; according to the hinge axis inclination range from 0 to 4 degrees between the straight line y = B counterclockwise rotation around the O point of angle θ, to be the axis position O1O2.

According to the hinge spacing 300 to 500 mm, to hinge center O as the initial point along the line y = B to determine the two points D and E, the length of line segment between two points L, L value, and adjust the distance between the axis of the outer plate to ensure that the width in the direction of the hinge plate without interfering with the outer case, the axis of the outer plate as close to the limit position (L values that are known to time) and if the L value can be changed, you might consider slightly reducing the L value, closer to the axis of the outer plate (car door panel curvature is large). by changing the initial value of B for re-generating axis O3O4 or O1O2 of parallel lines to change the distance from the axis to the outer plate when the axis position is finalized, according to D 、 E two o'clock position of the hinge model can be correctly placed in the door the door cavity, to be further movement checking and collision detection.