Rear door hinge structure design scheme_hinge knowledge 3

1.

The wide-body light passenger project is a digitally-driven and meticulously planned endeavor. Throughout the entire project, the digital model seamlessly integrates shape and structure, utilizing accurate data, fast modifications, and smooth interface with structural design. This interactive process incorporates structural feasibility analysis at each stage, ultimately achieving the goal of a structurally feasible and aesthetically pleasing design, which is then released in data form. This article focuses on the examination of the CAS digital analog Checklist during the backdoor hinge opening process.

2. Rear door hinge axis arrangement

The key aspect of the opening motion analysis lies in the layout of the hinge axis and the determination of the hinge structure. As per the vehicle's specifications, the rear door needs to open 270 degrees. Considering the shape requirements, the outer surface of the hinge must align with the CAS surface, while ensuring that the hinge axis inclination angle is not too large.

The step-by-step analysis of the hinge axis layout is as follows:

a. Determine the Z-direction position of the lower hinge. This takes into account the space required for the arrangement of the reinforcement plate and considers factors such as strength, welding process size, and assembly process size.

b. Position the main section of the hinge based on the determined Z-direction position. Consider the installation process and determine the four-axis positions of the four-linkage through the main section, with parameterization of the four-link lengths.

c. Determine the four axes with reference to the inclination angle of the benchmark car's hinge axis. Use conic intersection to parameterize the values of the axis inclination and forward inclination.

d. Determine the position of the upper hinge based on the distance between the upper and lower hinges of the benchmark car. Parameterize the distance between the hinges and create normal planes for the hinge axes at the respective positions.

e. Detail the layout of the upper and lower hinge main sections on their respective normal planes. During the process, adjust the axis inclination angle to ensure alignment with the CAS surface. Consider hinge installation, manufacturability, fit clearance, and structural space of the four-bar linkage mechanism, without focusing on detailed hinge structure design.

f. Conduct DMU movement analysis using the determined axes to analyze the back door's movement and check for safety distances during opening. Generate a safety distance curve through the DMU module and determine if it meets the defined requirements for minimum safety distance.

g. Perform parametric adjustment by tweaking the hinge axis inclination angle, forward inclination angle, connecting rod length, and distance between the upper and lower hinges within a reasonable range. Analyze the feasibility of the rear door's opening process and limit position safety distance. Adjust the CAS surface if necessary.

The hinge axis layout requires multiple rounds of adjustments and checks to fully meet the requirements. It is crucial to note that any adjustments to the axis necessitate a complete readjustment of subsequent layout processes. Hence, the axis layout must undergo thorough analysis and calibration. Once the hinge axis is finalized, detailed hinge structure design can commence.

3. Rear door hinge design scheme

The rear door hinge employs a four-bar linkage mechanism. Due to significant shape adjustments compared to the benchmark car, the hinge structure requires substantial modifications. Adopting a recessed structure design poses challenges in forming the side wall structure. After considering several factors, three design options for the hinge structure are proposed.

3.1 Scheme 1

Design idea: Ensure alignment between the upper and lower hinges with the CAS surface. Make the hinge side consistent with the parting line. Hinge axis: Inward tilt of 1.55 degrees and forward tilt of 1.1 degrees.

Appearance disadvantages: Large difference between the hinge's closed and open positions, leading to misalignment with the door and side wall.

Appearance advantages: Flush outer surface of upper and lower hinges with the CAS surface.

Structural risks:

a. Significant adjustment to the hinge axis inclination angle, which may impact automatic door closing.

b. Longer inner and outer connecting rods of the hinge to maintain safe distance, potentially causing door sagging.

c. Divided side wall of the upper hinge could complicate welding process and result in potential water leakage.

d. Poor hinge installation process.

3.2 Scheme 2

Design idea: Protrude both upper and lower hinges outwards to eliminate gaps with the rear door in the X direction. Hinge axis: Inward tilt of 20 degrees and forward tilt of 1.5 degrees.

Appearance disadvantages: Increased outward protrusion of upper and lower hinges.

Appearance advantages: No fit gap between the hinge and the door in the X direction.

Structural risks: Slight adjustment to lower hinge size to ensure commonality with the upper hinge. Minimal associated risks.

Structural advantages:

a. Common four hinges, resulting in cost savings.

b. Good assembly process for door linkage.

3.3 Scheme 3

Design idea: Align outer surface of upper and lower hinges with the CAS surface, while matching the door link with the door. Hinge axis: Inward tilt of 1.0 degrees and forward tilt of 1.3 degrees.

Appearance advantages: Better alignment of hinge's outer surface with the CAS surface.

Appearance disadvantages: Large gap between the hinged door link and the outer link.

Structural risks:

a. Significant adjustment to the hinge structure, posing greater risk.

b. Poor hinge installation process.

3.4 Comparative analysis and confirmation of schemes

After discussions with the modeling engineer, considering structural and modeling factors, it is determined that the third solution is the optimal choice.

4. Summary

Hinge structure design necessitates comprehensive consideration of structure and shape, often posing challenges for optimization. With a forward-designed project, CAS design stage prioritizes structural requirements while striving to achieve maximum appearance modeling effect. The third design plan minimizes changes to the outer surface and maintains consistency in modeling effect. Therefore, the modeling designer leans toward this plan, taking into account our advanced production line and their confidence in the quality of our hinge products.