Claims:1. There was 40% reduction in weight of front and rear wheel assembly of the knuckle and hub of the Formula SAE car.
2. Due to reduction in weight in wheel assembly it directly improves handling and maximizes the efficiency
, Description:FIELD OF THE INVENTION
The invention is related to automobile engineering were the weight optimization of the knuckle and hub of the Formula SAE car used in front and rear - wheel assembly using the shape optimization technique. In this about 40% of hub weight was reduced.
BACKGROUND OF THE INNOVATION: -
Preamble to the Description
To designed and manufactured the Knuckle and hub for the Formula SAE. The design follows all the rules laid down by FSAE Rule Book for Formula Type Cars.
The objective of Optimization is always to find the best possible and suitable dimension. This is because optimization means finding out the dimensions which will be just enough to sustain the forces. There are a lot of forces acting on the wheels in the static and especially in the dynamic condition. As the Wheel assembly is directly connected to the wheels, all these forces also have an impact on the designing of the Wheel Assembly. A lot of forces act on the wheel assembly during accelerating, braking, cornering, and tilting. A good Wheel Assembly can sustain such forces over a longer period of time. Thus, it is required to design the wheel assembly considering all the factors.
Goal Statement and Task Specifications for the Uprights and Hubs
? Reduce unsprung mass.
? Must be the sole component in resisting forces in torsion and bending.
? Must withstand braking force.
? Must allow minimal compliance during cornering and bump loading.
? Must fixture a full floating rotor with an effective diameter of 8.75 inches.
? Must locate the wheel at the proper track width.
Summary of the Invention
It is implemented the shape optimization technique to optimize the design of the hub which is to be used in the front wheelset assembly of the car. The main objective of shape optimization is to reduce the weight of the hub. Due to the reduction in the weight of the hub, the weight of the whole wheelset assembly reduces. The FEA result indicates that the upright assembly is able to perform safely in real track conditions as per performance requirement.
Detailed Description of the Preferred Embodiment
Components of Wheel Assembly designed
1) Design of Knuckle
The upright connects the control arms to the hub which connects the upright to the wheels, allowing the vehicle to move. The uprights also connect to the steering arm, allowing the driver to steer the vehicle, and the caliper, allowing the driver to stop the vehicle. The upright is to remain stationary relative to the chassis while the hub is to rotate with the wheel. This is done by placing a bearing between the hub and upright. Typically, a spindle is pressed into the upright and does not rotate and a bearing is pressed into the hub, and the spindle is pressed into the bearings allowing the hub to rotate about the spindle as show in drawing 2.
The first step while designing the wheel assembly is to find out the required parameters in order to design the wheel assembly from the steering and the suspension geometry. Parameters such as King Pin Angle, Steering Arm angle, Tie rod angle are obtained from the Steering geometry, whereas the Caster angle, the angle of upper A-arm and the lower A-arm, Rear Track width are obtained from Suspension Geometry. Parameters like the Stub length and the front track width are obtained from both Geometries. Considering the Front Wheel Assembly the Parameters are as follows:
a) King Pine Inclination:-70
b) Caster Angle: - 50
c) Tie Rod Angle: - 3.940
d) Track Width: - 1200 mm
e) Wheel Diameter: - 406.4 mm
Finally, we have done an analysis of the part using FEA in ANSYS 17.0 software which ensures the safety of the part from failure as shown in drawing 3.
2) Design of Hub
Hub is a rotating part in the assembly where the disk is mounted on one side and wheels are mounted on another side as shown in drawing 1. The hub is directly connected to the wheel and is connected to the upright. This part gives a motion to the wheel and affects the overall performance of the car. Hence it is important to design this part by considering various safety considerations. For this purpose, shape optimization of the hub is done which actually gives an idea about the stresses which are induced in it and how much material we can remove so as to reduce the weight and it also gives an appropriate factor of safety to the part. After the shape optimization results, we have modified the cad design with reference to the shape optimization results. Finally, we have done an analysis of the part using FEA in ANSYS 17.0 software which ensures the safety of the part from failure as shown in drawing 4.
Industrial Applications
1. The student designed a car and is evaluated in static and dynamic events to find its potential for light weight production.
2. The knuckle and hub in light weight can be used for other teams; they can participate in SAE formula race competition.
3. The Formula SAE car is designed by students according to rule compliance which is checked during technical event.
Obviousness
The wheel assembly is an integral part of a Formula SAE (FSAE) car and consists of several components such as the upright, braking system, hub shaft and wheel. Each component must be designed to account for factors that will affect the entire assembly and its function. This improves handling and maximizes efficiency.
Non obviousness
Aluminum T6 material is used instead of cast iron for Knuckle and EN24 instead of aluminum for Hub. Aluminum has excellent properties such as lightness, thermal conductivity, rust formation and machining processing. EN24 gives high tensile strength to the hub and its is capable of retaining high impact.
Novelty
The novelty developed in knuckle and hub is to reduce the weight by 40% which reduce the cost and enhance the performance of vehicle. Due to reduction in weight there is increase in efficiency, reduce emissions and save environment.