Roof Design

OBJECTIVE:

To design the Front Roof rail, Bow Roof rail, Center Roof rail and Rear Roof rail as per the master sketchs. Also pass the Bow-Roof prediction and Snow load prediction conditions.

INTRODUCTION:

Car roof is the important composition parts of Integral automobile, and the fastness of car roof is directly connected to the quality of car performance; The processing technology of roof directly has influence on the anti-seismic performance of soundproof effect and the car of car inside; Therefore,, when processing roof, often adopt many roof cant rail actings in conjunction to guarantee the integral firmness of roof; Prevent the distortion of car body; Existing car roof processing technology more complicated, adopts pipelining, is all generally that next process could start through last process, and production efficiency is not high.

The invention discloses a manufacturing process of an automobile roof component. The manufacturing process of the automobile roof component comprises the following steps respectively consists of an outer plate processing process, a strip-shaped assembly and annular assembly processing process and an automobile roof side beam processing process, and finally, an automobile roof combining process comprises the following steps that 1, a plurality of M6 screw nuts are arranged on one side of an annular assembly through spot welding, and two M6 screw nuts are arranged at two ends of a strip-shaped assembly through spot welding; 2, the strip-shaped assembly is arranged at the other side of the screw nut corresponding to the annular assembly through spot welding, and in addition, the annular assembly and the strip-shaped assembly are punched for alignment; 3, the annular assembly is welded at the inner side of an outer plate; 4, an automobile roof side beam is arranged at the inner side of the outer plate through spot welding, and finally, an automobile roof is integrally subjected to burr grinding and ending. The manufacturing process of the automobile roof component disclosed by the invention has the advantages that the process is simple, and the production efficiency is high.

Types of roof reinforcements are as follows: -

• Front roof rail reinforcement (FR)
• Centre roof rail reinforcement (CR)
• Bow roof 1 rail reinforcement (BR1)
• Bow roof 2 rail reinforcement (BR2)
• Rear rail enforcement (RR)

DESIGN OF PART:

SECTION MODULUS ON THE O-Y SECTION FOR ALL THE ROOF RAILS:

• FRONT ROOF SECTION

• BOW ROOF 1 SECTION:

• BOW ROOF 2 SECTION:

• CENTER ROOF SECTION:

• REAR ROOF SECTION:

FORMULA USED:

• Bow–Roof Prediction Formula

W = [1.73 x 10^(-3) x L] + [1.85 x 10^(-8) x (R^2)/t] + [ 1.10x10^(-3) x l] - 2.68

Where,

L = Roof Length in X-Direction[mm](Roof dimension in 0-Y)

R = Roof curvature

R = 2(Rx*Ry)/(Rx+Ry)

Rx = X curvature

Ry = Y curvature

t = Roof plate thickness [mm]

l = Bow Roof Span [mm]

Judgment Condition

OK< 2.7

• Snow Load Prediction Formula

Qr = [Iy x t²] / [α x s x [(Rx + Ry)/2]² x 10^-8]

Note: The Qr value given over here is correct. There was a typo error in the formula given in the video.

Where,

α = My x Lx² x 10^-12 , My = Y(Ly-Y)

t = Roof plate thickness [mm]

Ly = Distance between the front and rear roof Rails on the Vehicle along with 0Y[mm]

Length of Roof panel with the center point between Roof rail Front /Rear as the front and rear reference point.

Lx = Distance between the Left and Right end of the roof on the Roof BOW [mm]

The width of the roof panel is exposed on the surface.

Y = Distance front Front Roof Rail to Roof BOW[mm]

s = Distance for which Roof BOW bears divided load [mm]

s = L1/2 + L2/2

Iy = Geometrical moment of inertia of Roof BOW (Y cross-section )[mm4]

Rx = Lateral direction curvature radius of roof panel Y cross-section on Roof BOW [mm]

Roof panel curvature Radius of the Length Lx in Front view

Ry = Longitudinal Direction curvature radius of the Roof panel X cross-section on Roof BOW [mm]

Roof panel X curvature radius of length s in Side view

Judgment condition

Qr ≥ 3.1

250 ≤ s ≤ 380

FROM THE ABOVE REPORT, THE SNOW LOAD CRITERIA IS PASSED. THE VALUE OF Qr IS GREATER THAN 3.1.

CONCLUSION:

Design of Front Roof rail, Bow Roof rail, Center Roof rail and Rear Roof rail as per the master sketchs and passed the Bow-Roof prediction and Snow load prediction conditions is completed.