Polymer Sprocket Profile With Textile Reinforcement for High Torque
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Solution Overview
Problem
Conventional sprockets for high torque applications are often made of metal and have sprocket teeth that are narrower than belt teeth, leading to cracking and breaking, and non-metal pulleys are not adequately durable for such applications.
Innovation Solution
A high torque belt sprocket formed from a castable polymer material with a continuous toothed structure and embedded textile reinforcement, which provides shape maintaining strength and is free or devoid of metal structures, allowing for a stronger and more durable sprocket tooth design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional metal sprockets are used with narrow teeth, then the sprocket can be made compact, but the teeth are prone to cracking and breaking under high torque
Solution Approach 1:
The patent uses a composite material system consisting of a polymeric matrix material combined with embedded textile reinforcement. This composite structure provides the necessary tooth strength to prevent cracking and breaking under high torque while allowing for a more compact sprocket design compared to solid metal construction.
Solution Approach 2:
The textile reinforcement is strategically embedded in specific locations within the polymeric matrix, particularly in areas requiring enhanced strength such as the tooth roots and high-stress zones. This localized reinforcement approach optimizes strength where needed while maintaining overall compactness.
2Weight of moving object
If non-metal pulleys are used, then the weight is reduced, but the durability is insufficient for high torque applications
Solution Approach 1:
The patent employs a composite construction with a polymeric matrix material providing lightweight properties and embedded textile reinforcement providing structural strength and durability. This combination achieves both weight reduction and enhanced reliability for high torque applications.
Solution Approach 2:
The patent modifies the material parameters by selecting specific polymeric materials with appropriate mechanical properties and combining them with textile reinforcement having specific tensile strength and modulus characteristics. This parameter optimization enables the non-metal sprocket to withstand high torque loads while maintaining lightweight properties.
3Strength
If metal sprockets are used, then the strength is sufficient, but corrosion-resistant finishes are required adding manufacturing complexity
Solution Approach 1:
The patent eliminates the need for separate corrosion-resistant finishes by using a polymeric material that inherently resists corrosion. This extraction of the corrosion protection function from the manufacturing process simplifies production while maintaining sufficient strength through the composite construction.
4Productivity
If sprocket groove width is reduced to two thirds of pitch length, then more teeth can engage the belt, but the groove becomes too narrow for non-metal materials
Solution Approach 1:
The patent uses the composite material system with textile reinforcement to strengthen the groove structure, enabling it to support wider grooves that can accommodate non-metal belt materials while maintaining adequate torque transmission capacity through the reinforced construction.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A high torque sprocket (100) includes a body (102) formed of a castable polymer material defining an outer periphery (104) and a recessed hub section (106) defining an inner surface (110) for engaging a bushing (404) having a smooth circular outer surface and at least one threaded port (410) for securing with the high torque sprocket (100). A continuous toothed structure (108) is disposed on the outer periphery (104) of the body (102), which has a circular pitch (P). A textile reinforcement may be embedded in the body (102) adjacent the inner surface (110) of the hub section (106). The hub section (106) inner surface (110) is of a tapered shape and adapted to engage a conventional QD bushing (404) or a taper-lock bushing (404). The continuous toothed structure (108) may have a plurality of S-shaped grooves for engaging a belt (504) and having a groove width, and the ratio of the groove width to the circular pitch (P) may be 0.65 or less, or even a value selected from the range of 0.50 to 0.65.