The function of the rear bumper of a car
The main functions of the rear bumper of a car are as follows
Protect the rear of the vehicle
The rear bumper absorbs the impact force through energy-absorbing materials when a vehicle undergoes a rear-end collision or collision, reducing damage to the vehicle body. Its structure is made of lightweight materials such as polypropylene plastic, which can both buffer and disperse the impact force. The energy-absorbing box transmits the impact force to the front longitudinal beam, reducing maintenance cost-. .
Absorb collision energy
In a rear-end collision, the rear bumper consumes energy through its own deformation and the toughness of the material, reducing the harm to the occupants and the damage to the internal components of the vehicle.
Protect the safety of pedestrians
Designed with foam material, it reduces the impact force on pedestrians' legs during collisions and lowers the degree of injury to pedestrians.
Aesthetics and aerodynamics
The rear bumper is in harmony with the body lines, enhancing the overall visual effect of the vehicle. It also has aerodynamic functions to reduce driving resistance.
The rear bumper of a car is a safety protection device installed at the bottom of the rear of the vehicle, located between the taillight group and the rear license plate, and extends vertically to the edge of the chassis. It mainly undertakes the following functions:
Safety protection
It plays a buffering role in low-speed collisions, reducing damage to the vehicle body. For instance, in minor rear-end collisions, the rear bumper absorbs the impact force through structural deformation or material elasticity, reducing the harm to occupants and the vehicle.
Aesthetics and aerodynamics
The use of lightweight materials such as polypropylene plastic not only maintains the smoothness of the rear styling but also reduces driving resistance and improves fuel economy.
Material selection
Youdaoplaceholder0 metal materials (such as high-strength steel) have high strength but are heavy;
Youdaoplaceholder0 plastic materials (such as polypropylene) are light in weight and easy to process, but have relatively weak impact resistance;
Youdaoplaceholder0 composite materials combine the advantages of both and become the mainstream choice.
The difference from anti-collision beams
The anti-collision beam is located behind the rear bumper and is made of boron steel plate, mainly protecting core components such as the water tank and engine. The rear bar uses soft materials to buffer the impact during a collision, reducing the harm to pedestrians.
The repair or replacement plan for the rear bumper failure of a car should be selected based on the degree of damage. Common causes of failure include material aging, collision and environmental erosion, etc.
Fault handling plan
Youdaoplaceholder0 Minor damage (such as superficial scratches or small cracks) :
After cleaning the surface, fill the gaps with plastic repair glue or special repair glue and cure with a baking lamp
For deep cracks, drill holes at the end of the crack to prevent extension, apply epoxy resin glue and reinforce with a plastic welding torch
Youdaoplaceholder0 severe damage (such as twisting, cracking or penetrating damage) :
If the crack causes the structure to loosen or the area to be too large, it is recommended to replace the original factory/aftermarket parts (make sure the model matches the vehicle)
When safety structural components (such as metal brackets) are damaged, they must be replaced and cannot be repaired
Common causes of faults
Youdaoplaceholder0 Material aging : Long-term exposure to sunlight and ultraviolet radiation lead to a decline in the performance of plastic materials, and high temperatures in summer intensify the difference in expansion and contraction
Youdaoplaceholder0 Collision damage : cracking and deformation caused by external force impact during driving or parking
Youdaoplaceholder0 Environmental erosion : Rainwater seeping in causes internal rusting and accelerates material aging
The core criterion for determining whether the rear bumper of a car needs to be replaced
Youdaoplaceholder0 structural damage
If the lifting lugs, bolts or fixed brackets near the wheel position of the rear bumper break or have their feet broken, they must be replaced to ensure driving safety .
If key support points (such as the connection points of anti-collision beams) show depressions or cracks, they should be replaced first rather than repaired .
Youdaoplaceholder0 Degree of crack and deformation
When the length of a single crack is ≥20 cm, or the cumulative length of multiple cracks exceeds the standard (such as two ≥15 cm, three or more ≥10 cm), needs to be replaced.
When the area of the bumper distortion caused by a collision is ≥1/3 or affects the overall structural strength, it is recommended to replace .
Youdaoplaceholder0 Function and safety impact
When damage causes the bumper to be unable to effectively absorb collision energy or affects the accuracy of sensors (such as reversing radar, cameras), needs to be replaced.
If there is a risk of detachment or damage to the stress concentration area after repair, should be replaced directly.
Decision-making suggestions for repair and replacement
Youdaoplaceholder0 priority to fix :
Minor scratches, superficial cracks or small depressions can be repaired by professional bodywork and painting or plastic welding .
When the original factory bumper does not meet the replacement standard, the repair can retain the original factory matching degree and safety .
Youdaoplaceholder0 must be replaced :
Damage involving structural integrity or functional failure (such as fixed-point fracture, large-area crack) .
When there is a significant color difference or quality discrepancy between the aftermarket parts and the original ones, it is recommended to replace the original parts at the 4S store .
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