How to Choose the Right Drive Wheel for Your Material Handling Project
A drive wheel converts electric power into tractive force that causes a vehicle to move. The wheels can be configured to fit a range of applications.
The right drive wheel configuration can enhance an individual’s function, independence and quality of life. But selecting the correct configuration can be a daunting task.
Design Requirements
Every material handling project has a unique set of requirements and each will require a different wheel configuration. Transporting a coil car across a factory floor requires a very different solution from moving a top-heavy load that needs to move with precision starting and stopping points on an indexer or palletizer machine.
Because drive wheels do not pivot like casters they must be able to carry loads in a unidirectional manner. Moreover, since they are powered it is important that the force of the motor is able to be transferred to the ground with minimal effort. Consequently, a wheel block that contains the wheel, bearings and support structure is an ideal choice for this type of application.
The upright, braking system and hub shaft of the drive wheel wheel assembly must be designed to meet FSAE specifications and Australian standards. This is accomplished by utilizing load calculations, modeling via SolidWorks and finite element analysis via Ansys for each component of the wheel assembly.
Because the wheel assembly has a large number of critical components, it is often one of the most difficult parts of a vehicle for students to design and build within their FSAE project cycle. This is especially true when the team has to manage several sub-teams, such as a chassis team that leads the structural and composite work, a drivers team managing the ergonomics and drivers and an electrical team handling all internal electronics.
Materials
In general, drive wheels need to be made from materials that can withstand high capacity demands and extreme environmental conditions. For instance, they must be able to resist high temperatures, and they must be able to stand up to repeated use on rough surfaces without being damaged or losing strength.
Forged metals are typically the best choice for drive wheels, as they are stronger than standard cast wheels. During the forging process, the molecules in the metal are subjected to tremendous forces that cause them to rearrange and strengthen their molecular structure. This translates to greater durability and reliability for the wheel.
Steel wheels are often the go-to option for most applications because they are a cost-effective solution. However, their weaknesses include a tendency to bend or crack under heavy loads and in harsh environments. Luckily, there are other options for those who need to move heavy or precise loads throughout a facility.
A direct-drive wheelbase is a system that includes a motor, gearbox, and wheel block all within one fixed housing. This allows for fast installation and requires less engineering than other systems that incorporate separate components. Depending on the application, the motor and drive wheel may also need to be connected with a rotary encoder or controller board that translates FFB data into steering wheel forces.
Design Considerations
A wheel has to withstand the load and environmental stresses that it is subjected to. It must also be efficient to reduce friction between the components. Mechanical components that are directly mounted on a 36v bldc motor shaft such as gears, couplings and cams can generate friction if they don’t have proper design. They should have as little friction as possible and be able to spin freely for at least five revolutions without a noticeable increase in effort to rotate them. Shafts are usually supported on bearings that have been designed to withstand these loads and environmental conditions.
Drive wheels must also be able to move over rough terrain. Uneven or slippery terrain can separate drive wheels from the ground leaving only a point of contact which increases drag on the wheelchair and limits the driving force that can be applied to each wheel. Wheels with multiple points of contact can decrease this effect and provide better performance on rocky or muddy terrain.
Individuals who use power wheelchairs often have to navigate tight spaces at home including bathrooms, bedrooms and kitchens. The turning radius of the wheel configuration can be a major factor in this decision as well as the ability to reverse the chair when necessary. Some individuals require a small turning radius while others can easily handle a full 360-degree turn.
Maintenance
There are a variety of factors that impact the lifespan and performance of a wheel loader. Routine daily inspections, a strong maintenance program, and prioritising safety can significantly reduce the likelihood of equipment failures.
To maximise the lifespan of a drive wheel, it is important to regularly clean the wheels and remove dirt and corrosion from their mounting surfaces. When cleaning, use a non-acidic cleaner and pay particular attention to the wheel’s spokes, crevices, and lug nuts.
Additionally, newly-installed wheels should be re-torqued after 100km to ensure that they are still tight. It is also essential to check lug nuts for signs of looseness or damage and replace them as necessary. The wheel loader’s front differential needs to have its fluid drained and replaced at regular intervals (every 30,000 to 50,000 miles).
Four-wheel drive vehicles are becoming increasingly popular, but they do require a little more maintenance than two-wheel drives. For example, the front and rear differentials require lubrication, as well as the ball joints, driveshaft U-joints, slip joints, and suspension arms. It is also recommended that 4WD drivers use a self-leveling system to maintain a consistent ride height, which will extend the life of the front axle and drive wheel.
Streamline your fleet’s maintenance processes by adopting industry-standard best practices, including training employees in safe and effective methods of work. Additionally, optimise maintenance tasks with FieldInsight, which helps streamline task allocation and scheduling, whilst allowing for the creation, management, and retrieval of detailed maintenance records.
