Technical Bulletin TB3000-2 - ◄ back to technical data

Applications Using the STPD Profile

For most applications, a trapezoidal tooth profile is sufficient to satisfy power transmission requirements. However, an STPD profile is necessary when higher torque, accurate positioning, or quieter operation is required. Typical applications using STPD profiles are:

  • Computer peripherals
  • High speed packaging equipment
  • Industrial sewing machines
  • Robotics
  • Office automation machines
  • Vending machines
  • Household appliances

Advantages of STPD Profile

The STPD belt tooth has a rounded profile (as shown in Figure 3) for smoother operation. The mating pulley groove (as shown in Figure 4) features an arched top on the bottom of the groove and a groove depth (H') that is smaller than the belt tooth height (H). This unique profile has the following advantages:

  • High torque transmitting capacity.
  • Less noise generation due to smoother tooth in mesh and better stress distribution.
  • Accurate positioning due to reduced backlash
  • Smaller shaft loads due to lower belt tension requirements.
Tooth Profile Comparison: Curvilinear (STPD) vs. Trapezoidal


Tooth Profile Geometry

The shape of a timing belt tooth is directly related to the power transmission efficiency of a drive system. The tooth profile can have either a trapezoidal or a curvilinear profile. The trapezoidal profile is based on industry standards, while the curvilinear profile is based on the Chemi-Flex proprietary Super Torque Positive Drive (STPD) design. Both tooth profiles and corresponding pulley grooves are illustrated below:

Figure 1: Belt Trapezoidal Tooth Profile
Figure 3: Belt STPD Tooth Profile
Figure 2: Pulley Trapezoidal Tooth Profile
Figure 4: Pulley STPD Groove Profile

Engineering Assistance

For additional technical information or product testing, please don't hesitate to contact the Chemi-Flex Engineering Department at
(630) 627-9650.
Chemi-Flex believes the information presented is accurate at the time of publication and is intended for comparison purposes only. It is the end users responsibility to test products to insure they meet requirements for each application. Reference to products not manufactured by Chemi-Flex is neither an endorsement nor unsuitability of similar products.

 
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