friction of different belt types on a metal pulley

Description:

• The belt drives are machine elements that are classed as traction mechanisms in the field of transmission or conversion elements.
• They transfer torque and speed between guiding members such as wheels or pulleys.
• The motion is transferred by traction mechanisms that can only absorb tensile forces.
• Toothed belts and chains deliver positive transmission of movements.
• Traction mechanisms such as cables, flat belts and V-belts, on the contrary, allow for non-positive transmission.
• In non-positive belt drives, the circumferential force between the belt and the pulley is transmitted according to the principle of cable friction.
• Cable friction arises due to tangential static-friction forces at the points where the cable is in contact with the wheel or the pulley.
• Eytelwein’s cable friction formula is used to calculate both cable and belt friction.
• The TM 220experimental unit allows the study by experiment of belt drives and belt friction.
• At the core of the experimental unit is a cast iron pulley, whose circumference features grooves for V-belts and flat belts.
• The pulley is mounted on ball bearings and is powered by a crank handle.
• Its flywheel mass favours an even rotation of the pulley.
• The belts rub on the pulley at a wrap angle between 30° and 180°.
• The wrap angle can be adjusted in increments of 15°.
• Two spring balances detect the tensile forces on the respective belt ends.
• This makes it possible to precisely adjust the belt tension using a threaded spindle.
• Two flat belts made of different materials, a V-belt and a cable belong to the scope of delivery.
• The experiments compare different belt types and materials and investigate the effect of the wrap angle.
• In addition, for V-belts, it is possible to study how the groove shape affects the coefficient of friction.

Technical Details:

Specification:

1. function of a belt drive
2. belt friction and comparison of different belt materials and types
3. ball-bearing mounted pulley with 3 different belt grooves
4. 2 flat belts made of different materials, 1 V-belt and 1 cable
5. wrap angle of the belts 30°…180°, graduation 15°
6. force measurement with 2 spring balances

Technical Data:

Flat belts:

• 1x leather/polyamide, 15×2,2mm, Extremultus LT10
• 1x polyamide, 15×0,6mm, Extremultus TT2

V-belt:

• ISO 4184
• profile: SPZ
• 9,7×8,0mm, rubber/fabric

Cable:

• hemp, Ø=3mm

Pulley:

• Ø=300mm
• material: grey iron
• Dynamometer: 100N ±1N

Dimensions & Weight:

• L x W x H: 700x350x1100mm
• Weight: approx. 47kg

Learning Objectives/Experiments:

• effect of wrap angle, coefficient of friction and cable force (Eytelwein’s belt friction formula).
• comparison of flat belts and V-belts.
• consequences of an unadopted V-belt groove.

Scope of Delivery:

• 1 experimental unit
• 2 flat belts
• 1 cable
• 1 V-belt
• 2 dynamometers
• 1 set of instructional material

Features:

• function of a belt drive

Accessories:

·         Optional: WP 300.09 Laboratory trolley

Due to the continuous development of our products, the goods supplied may vary in detail to that illustrated on this Website.