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The circular arc tooth belt is a part of transmission components, which transmits power through the meshing of belt tooth and tooth groove of the belt pulley. Compared with the trapezoidal tooth belt, the circular arc tooth timing belt has a circular arc tooth shape, which makes the transmission more stable and the carrying capacity higher. It is suitable for the applications of high load and high speed.
The circular arc tooth synchronous belt has several series according to the tooth profile, the common ones are HTD, STD and RPP, this text mainly introduces the differences between them and the application situations.
Tooth Design Differences: Core Differences
HTD Toothed Drive Belt (Full Arc Tooth)
The tooth shape of HTD is full arc structure, which makes the tooth and the pulley has more contact area to enhance smooth transmission and load capacity. The tooth tip and root are circular arc, which can better disperse the stress during transmission and reduce the risk of tooth root fracture. HTD is often used in high-torque transmission scenarios, such as industrial machinery and automation equipment. Its models are 3M, 5M, 8M and 14M, etc.
| Type | HTD3M | HTD5M | HTD8M | HTD14M |
| Pb（mm） | 3 | 5 | 8 | 14 |
| ht（mm） | 1.22 | 2.06 | 3.38 | 6.02 |
| hs（mm） | 2.4 | 3.8 | 5.6 | 10 |
STD Toothed Drive Belt (Semi-arc Tooth)
STD is an upgraded version of HTD, the tooth shape is flat and semi-arc, the tooth tip is flat while the tooth root is still arc. This design reduces the slides between the tooth and the pulley, improving the accuracy and stability of the transmission and reducing noise. It is suitable for equipment which requires precision transmission, such as medical instruments and CNC machine tools. Its specifications are S3M, S5M, S8M, S14M and so on.
| Type | STD3M | STD5M | STD8M | STD14M |
| Pb（mm） | 3 | 5 | 8 | 14 |
| ht（mm） | 1.14 | 1.91 | 3.05 | 5.3 |
| hs（mm） | 2.4 | 3.4 | 5.3 | 10.2 |
RPP Toothed Drive Belt (Arc Tooth with Grooves)
RPP adopts design of arc tooth with a notch to further optimize the meshing degree between teeth and pulley and reduce the risk of slipping. And this design improves tooth belt flexibility and good turning effect. It is suitable for high-speed, high-precision transmission scenarios, such as high-end printers or precision robots. Specifications such as RPP5M, RPP8M, RPP14M and so on.
| Type | RPP5M | RPP8M | RPP14M |
| Pb（mm） | 5 | 8 | 14 |
| ht（mm） | 1.95 | 3.2 | 6 |
| hs（mm） | 3.8 | 5.4 | 10 |
Comparisons of Performance and Application Scenarios
| Type | Transmission Efficiency | Noise Control | Applications | Compatibility |
| HTD | High | Medium | Industrial Machinery | HTD Pulley |
| STD | Extreme high | Low | Precision instruments, medical equipment | STD Pulley |
| RPP | High | Extreme low | High speed printer, precision automation equipment | Not compatible with HTD/STD pulley |
Key Points for Timing Belt Model Selection
Load, speed, transmission accuracy and environmental conditions all needed to be considered comprehensively when selecting timing belt models. HTD or RPP series can be used in situations with light loads and high speed. STD is recommended in scenarios with heavy loads, low noise and low speed. If there is oil and dust in the environment, it is necessary to match the polyurethane material toothed belt, which has better wear resistance and chemical corrosion resistance than rubber material.
There was a food factory packaging line stopped production due to frequent breakage of the timing belt, after the investigation we found that the original design used HTD8M belt, but the actual load peak exceeded the rated value by 30%. After replacing STD-8M belt and adding tension wheel, continuous operation for half a year without fault, transmission efficiency increased by 18%. This case shows that accurate calculation of operating parameters and reserving 20% safety margin can effectively extend the life of the synchronous belt.
Why Choose Puteken Circular Arc Tooth Belts?
Puteken is a supplier of toothed drive belts, offering both T-type and circular arc timing belts. We provide a variety of materials, including rubber and PU, and can add various coatings such as red glue, APL, foam, transparent PU, silicone, Kevlar felt, and rough-top PVC.
Puteken’s Circular Arc Tooth Belts are designed to deliver optimal performance for a wide range of industrial applications. Here’s why they stand out:
- Enhanced Durability: The unique circular arc tooth design minimizes wear and extends belt life, providing a longer-lasting solution for your machinery.
- Superior Power Transmission: The innovative tooth shape reduces the risk of slippage, ensuring efficient and reliable power transmission even under heavy loads.
- Quiet and Smooth Operation: Thanks to the advanced design, these belts reduce vibration and noise, offering a quieter and smoother operational experience.
- High Efficiency: With reduced friction and improved tooth engagement, the Circular Arc Tooth Belts deliver greater energy efficiency, helping to lower operational costs.
- Customizable Solutions: Puteken offers a range of sizes and materials to meet specific application requirements, ensuring a perfect fit for your equipment.
- Reliable Performance: Whether in high-speed or high-torque environments, these belts provide consistent, high-performance operation across a wide range of industries.
Choosing Puteken means investing in quality, efficiency, and reliability for your machinery. Don’t settle for less when you can get the best!
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