3/17/2023 0 Comments Ramp physics calculatorThe factors that can be usually ignored during calculations are: Floor conditions (roughness, cleanliness, slope, etc.).The most significant factors to be considered are: As one might suspect, a softer wheel tread material will generally result in greater rolling resistance than a very firm/hard wheel tread material. However, bearing selection can be very important for other reasons such as load capacity, manual or towed operation, presence of shock loading or side thrusts, and desired maintenance. Anti-friction bearings don’t make as big a difference to rolling resistance as factors such as wheel material and wheel diameter. Wheel bearing selection in regard to rolling resistance is not as critical as the wheel material and diameter. Optimize by doing both-use the largest practical diameter wheel with the lowest coefficient of rolling resistance. To reduce the force required to overcome wheel rolling resistance, one can select a wheel with a lower coefficient of rolling resistance (for example, the forged steel wheel has coefficient of rolling resistance of 0.019 in.) or use a wheel with a larger diameter. This force is called the sustained or rolling force. Once in motion at a relatively constant speed, the force requirement is generally lower. Fortunately, the initial forces typically last only a short time and drop to the sustained force levels once the acceleration begins and any mechanical interference at the start of movement is overcome. Ergonomists refer to this force as the initial or starting force. The force required to push/pull wheeled equipment is always greatest at the start, just before movement begins. Imagine pushing a refrigerator or a piano without wheels! Furthermore, consider how much easier it would be to push the box (mentioned earlier) across the floor if it were on wheels. The reason we use wheels in material handling is the significantly lower effort (force) required to move an object. In this example, the person pushing is producing the “applied force,” and the box weighing “N” and the floor create the “friction force” which tends to resist that motion. Once moving, dynamic friction requires a relatively constant force to maintain that motion. Static friction requires a certain applied force to get the box moving. Imagine the force required to push a heavy box across a floor. The diagram below addresses sliding friction. The coefficient of (sliding) friction depends on the materials used for example, steel on ice has a low coefficient of friction, while rubber on pavement has a high coefficient of friction. Coefficient of (sliding) friction is a unit-less number that describes the ratio of the force of friction between two bodies and the force pressing them together. Rolling resistance measures the energy lost as something is rolled a specific distance.Ĭoefficient of rolling friction should not be confused with coefficient of sliding friction or, as it is often called, the coefficient of friction. Bicycling across a paved roadway is much easier than across a white sandy beach. Sand is a good example of a soft, rolling-resistant surface. The flat surface may also deform, particularly if it is relatively soft. The tire will deform to some extent, and that deformation will cause some resistance to the rolling motion. Consider a tire rolling on a flat surface. It is normally expressed in pounds and is a measure of the energy dissipated per unit of distance rolled. Rolling resistance is a measure of the retarding effect of a floor surface at the tread/floor interface of the wheels. This article will focus on rolling resistance, an important facet of industrial wheels. It can be either beneficial (when we brake our car to stop) or detrimental (when we try to drive with one foot on the brake pedal). Friction is the resistance to sliding, rolling, or flowing motion of an object due to its contact with another object. Friction plays a major role in the industrial world, and also in everyday life.
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