Fender Design - Wheel Arch Challenge

AIM

To calculate the Wheel Arch gap at required points and check whether the car passes the European standard.

THEORY

Fender

Fender is the American English term for the part of an automobile, motorcycle or other vehicle body that frames a wheel well. In other words, a fender is the curved portion of the car's body that sits over and houses the wheels. The purpose of a fender is to keep mud, rocks, and other road debris from being thrown around by the tires. i.e, the fender is a housing for the wheels that keeps road debris contained. If there was nothing covering the wheels, all kinds of debris would be kicked up by the rotating tires. The fender not only protects your car from sustaining damage from road debris but it prevents this debris from being thrown up at other vehicles on the road. This is why vehicles with large, oversized tires are often required by law to install fender flares.

Wheel Arch

The wheel arch is the semicircular part positioned above the wheel of a vehicle or the shaped part of the bodywork of a car or other vehicle that allows the wheel to be accessed, and in the case of front wheels, enable them to be steered. The wheel arch is designed considering all possible motions the tire undergoes while vehicle is running. It also ensures stopping any stones or other particles that could possibly fly outside the wheel well and hit the pedestrians.

DESIGN CONSIDERATION

There are some standards that has to be followed for designing the wheel arc according to different countries. Our design should meet this standards to meet the expectations.

Japan Requirement

• From the wheel centre draw horizontal and vertical axis and draw lines which are `50^o` to right and `30^o` to left with respect to vertical line as shown in figure.
• Take 2 points on the two lines drawn, central vertical line and project it to fender and tire at top view and mark it as A, B, C as shown in figure.
• Calculate the distance between the points, L for A, B, C and it must be minimum 5mm.
• The wheel guard distance value (a) at `50^o, 30^o` and central vertical axis must be greater than 5mm.

US Requirement

• Here the distance between tire and wheel arch is measure for every `10^o` from `-20^o` to `180^o`.
• The value of the L must be of 5mm in every point
• The wheel guard distance value (a) must be greater than 5mm.

Europe Requirement

• As shown in above figure, in European Standard, the value of L at 5 points SA, SB, SC, SD, SE must be minimum 10mm.
• The wheel guard distance value (a) must be greater than 5mm.

DESIGN

Procedure

• Project outer edges of Fender and Tire.
• Create a plane on the outer most curve of the tire which has origin as tire centre.
• Draw horizontal reference axis and vertical line (SA).
• From the vertical line draw two lines which are `50^o` to right and `30^o` and name it as SB, SC respectively.
• Draw a line SE which is at a distance of 150mm from horizontal reference axis.
• Draw a line SD which is at midpoint to SC and SE
• Create intersection points on outer most cure of Tire and fender.
• Project those 5 points on to fender body.
• Measure the distance between ppoints to get the value of L and a.

SOFTWARE USED

Siemens Nx 12

RESULTS

L value at SA

L value at SB

L value at SC

L value at SD

L value at SE

a value at SA

a value at SB

a value at SC

L value

REGION	REQUIRED VALUE (mm)	OBSERVED VALUE (mm)	RESULTS
SA	10	9.9490	FAILED
SB	10	10.00	PASSED
SC	10	0.1139	FAILED
SD	10	2.8875	FAILED
SE	10	5.9973	FAILED

a Value

REGION	REQUIRED VALUE (mm)	OBSERVED VALUE (mm)	RESULTS
SA	5	27.8310	PASSED
SB	5	43.6263	PASSED
SC	5	38.3597	PASSED

• The Fender is meeting wheel guard distance standard as all the values are above 5mm.
• The Fender does not meet the European Regulation standards as the distance between fender wheel arch and tire for 4 out of 5 points are less than 10mm.
• Here in some of the area the position of the tire is outside the fender.

If the tire is outside the fender, chipping will be more. so it will affect the pedestrians. So to have pedestrian safety we have to position the tire inside fender.

• The Fender does not meet the European Regulation

CONCLUSION

Wheel Arch gaps at required points have been calculated and checked whether the car passes the European standard.