Worm Gear Motor Deceleration With Asymmetric Pressure Angles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The precision of the worm wheel in motor deceleration mechanisms is compromised due to non-uniformity in resin teeth, leading to fluctuations in rotation resistance and load, making precise control difficult, and affecting detection precision in motor control systems.
Innovation Solution
A motor design where the worm wheel's pressure angle is larger than the worm's, with the worm made of steel and the wheel of resin, ensuring consistent engagement points and reduced fluctuations by tapering the worm wheel teeth, thus maintaining smooth engagement and precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the worm wheel is made of resin to reduce weight, then the motor weight is reduced, but the manufacturing precision of the teeth decreases due to shrinkage during cooling and curing
Solution Approach 1:
The patent changes the pressure angle parameter of the worm wheel teeth to be larger than that of the worm teeth. This parameter modification compensates for the dimensional variations caused by resin shrinkage, ensuring that the engagement between worm and worm wheel remains smooth despite the lower manufacturing precision of the resin worm wheel.
2Ease of operation
If the pressure angles of the worm and worm wheel teeth are made equal for proper engagement, then the engagement is smooth in theory, but the non-uniformity in resin worm wheel teeth causes fluctuation in the number of engagement points
Solution Approach 1:
The patent modifies the pressure angle parameter by making the worm wheel teeth have a larger pressure angle than the worm teeth. This asymmetric parameter setting creates a more robust engagement pattern that is less sensitive to the non-uniformity in worm wheel tooth dimensions, thereby maintaining consistent engagement points throughout rotation.
Solution Approach 2:
The patent introduces asymmetry in the pressure angle relationship between the worm and worm wheel. Instead of using equal pressure angles, the worm wheel is designed with a larger pressure angle, creating an asymmetric engagement geometry that compensates for manufacturing variations and ensures reliable engagement.
3Reliability
If high precision molding is required for the resin worm wheel to ensure consistent engagement points, then the engagement stability is improved, but the manufacturing cost increases
Solution Approach 1:
The patent changes the pressure angle parameter to create a more tolerant engagement geometry. By making the worm wheel pressure angle larger, the design becomes less sensitive to dimensional variations in the molded teeth, allowing for lower precision molding while maintaining engagement stability and reducing manufacturing costs.
Data Source
AI summary
Because the pressure angle β° (=12°) of teeth (47) of a worm wheel (46) is larger than the pressure angle α° (=11°) of teeth (45) of a worm (44), tips of the teeth (47) of the worm wheel (46) can be more tapered as compared with a case in which the pressure angle of the teeth of the worm and the pressure angle of the teeth of the worm wheel are the same angle (the conventional case). Thereby, it is possible to ensure non-contact of teeth, which had been variable in terms of contact and non-contact in the case of the conventional form, even if there has been non-uniformity in the teeth (47) of the worm wheel (46).