With sheave drives of flexible speeds, the flexible speed v-belt on the other hand can work. It makes a great deal of lateral rigidity to assist maintain consistent speed control because of this. There are also other alternatives you can make to modify your v-belt, making it exclusive, in addition to choosing between poly v-belts and flexible speed v-belts. For the function they will operate, these belts can come in a large variety of surfaces depending on what is needed. Ribbed ones, notched ones, cogged ones, banded ones, wedged ones, and smooth ones are some of the most ordinary forms of v-belts each of which is specially designed to help serve a different objective.
The guides for the v-belts can also come in numerous kinds, mostly based on shapes and surfaces with the most common shapes being a triangle profile, a rectangle profile, a unique rectangular profile, and a unique v-profile. Because of their flexibility, V-belts are generally used as well as the capability to handle directional changes that might prove challenging with other kinds of conveyor belts. Basic responsibilities such as product alignment, offsetting connections, switching, merging, and directional modifications can be utilized.
The different kinds available are what make v-belts so adaptable. Numerous features are ordinary for all these belts, no matter which kinds of v-belts you choose or what surface you select for. Because of their capabilities with directional changes, they are generally available in tight radius shapes, they will all go along a belt path which removes the risk of bending back the belt.
In addition to sleeves that permit them to move the product through curves quietly while still keeping their orientation, they will almost continually have automatic drive pressure and true taper rollers. Despite their outward similarities, each of these belts is designed for a distinct purpose. Using the wrong belt could cause equipment damage or pose serious safety issues.
What is the right belt for the job? It depends on the application. Following are some environmental and application design criteria that will influence belt selection: Ambient temperature Oil resistance Ozone resistance Static conductivity Power capacity Pulsation or shock loading Small sheave diameters Backside idlers Misalignment tolerance Serpentine or quarter turn layout Minimal take-up Clutching High speeds Energy efficiency Dust and abrasives As you can see, there are many factors to consider before choosing the right V-belt for the job.
Generally speaking, V-belts fall into these classifications: Ambient temperature Heavy-duty Industrial machinery Continuous operation Heavy loads and often harsh conditions Light-duty Fractional horsepower applications Intermittent usage Automotive For this article, we'll confine our discussion to industrial heavy-duty and light-duty V-belts.
How V-Belts Work Unlike flat belts, which rely solely on friction and can track and slip off pulleys, V-belts have sidewalls that fit into corresponding sheave grooves, providing additional surface area and greater stability.
As belts operate, belt tension applies a wedging force perpendicular to their tops, pushing their sidewalls against the sides of the sheave grooves, which multiplies frictional forces that allow the drive to transmit higher loads. Figure 2 How a V-belt fits into the groove of the sheave while operating under tension impacts its performance.
Figure 2 — Vertical force Fv applied perpendicular to belt top creates high sidewall forces Fn to transmit higher loads. V-belts are made from rubber or synthetic rubber stocks, so they have the flexibility to bend around the sheaves in drive systems.
Fabric materials of various kinds may cover the stock material to provide a layer of protection and reinforcement. V-Belt Profiles Cross Sections V-belts are manufactured in various industry standard cross-sections, or profiles, including the following: Classical Narrow Metric Fractional Horsepower The classical V-belt profile dates back to industry standards developed in the s.
Belts manufactured with this profile come in several sizes A, B, C, D, E and lengths Figure 3 , and are widely used to replace V-belts in older, existing applications. Figure 3 — Classical V-Belt Profiles. V-belts with a narrow profile 3V, 5V, 8V have more steeply angled sidewalls than classical V-belts Figure 4 , providing increased wedging action and higher load capacity up to 3x that of comparable classical V-belts..
Figure 4 — Narrow V-belt Profiles. They are used to replace belts on industrial machinery manufactured in other parts of the world. Figure 5 — Metric V-belt Profiles. The fractional horsepower V-belt profile is designed for light-duty applications such as lawnmowers, snow blowers, attic or furnace fans, etc.
These belts have a thinner cross-section and lighter gauge tensile cord Figure 6 , making them more flexible and able to bend around small sheaves. Figure 6 — Fractional Horsepower V-belt Profiles. Notches reduce bending stress, allowing the belt to wrap more easily around small diameter pulleys and allowing better heat dissipation.
Excessive heat is a major contributor to premature belt failure. Engineering a notched belt is a balancing act between flexibility, tensile cord support, and stress distribution. Precisely shaped and spaced notches help to evenly distribute stress forces as the belt bends, thereby helping to prevent undercord cracking and extending belt life Figure 7.
Figure 7 — Bending stress red area is evenly distributed in a well-engineered notched V-belt, while the tensile cord between red and yellow bands remains well supported, all without sacrificing flexibility.
For applications with vibrating or pulsating loads, especially with long center distances, joined V-belts may be the answer. A joined V-belt is, in essence, a number of single V-belts joined together with a continuous tie-band across the back see Figure 8. Figure 8 — Joined V-belt.
A joined V-belt increases lateral rigidity to reduce belt whip and maintain stability under shock loads. It also simplifies installation and tensioning compared with multiple single belts. V-Belt Construction and Material Figure 9 describes the constructional components of standard and notched V-belts.
Each component has a vital role to play in how well V-belts perform and how long they last. Different materials and configurations can influence belt performance characteristics in specific applications. Figure 9 — Anatomy of a V-belt. The tensile cord is the load-carrying component of a V-belt.
Most V-belts are made with polyester cords, although some belts are constructed with aramid or Kevlar? In a well-engineered V-belt, the tensile cords and rubber body of the belt are chemically bonded to form one unit, allowing for equal load distribution and longer belt life. Tensile cords are supported by rubber stocks, both above over cord and beneath under cord.
Various synthetic rubber stocks are used by different manufacturers to provide heat resistance and reduce wear.
Some high-performance synthetic rubber compounds, such as ethylene, significantly extend a belt's operating temperature range and resist hardening, cracking, and premature failure.
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