Spring-Preloaded Worm Drive for Thermal Clearance Compensation
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Solution Overview
Problem
Worm drives with fixed clearances suffer from high friction, wear, and limited adjustability due to material thermal expansion differences and manufacturing tolerances, making them inefficient and unsuitable for precise applications.
Innovation Solution
A worm drive design with an adjustable pre-stressing mechanism using guide pins and a spring element to maintain optimal contact between the worm shaft and worm wheel, minimizing clearance and friction through axial movement and torque compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed clearance is provided between the worm shaft and worm wheel to compensate for thermal expansion and manufacturing tolerances, then reliability is improved, but manufacturing precision and positioning accuracy deteriorate
Solution Approach 1:
The invention replaces the fixed clearance design with a dynamic pre-stressing mechanism. The receiving unit of the worm shaft is made movable relative to the receiving unit of the worm wheel through guide pins, allowing the system to adapt its clearance dynamically. This enables the worm drive to maintain both reliability across temperature variations and manufacturing tolerances while achieving the clearance-free operation needed for high positioning accuracy in adjustment applications.
2Productivity
If different materials are used for the worm shaft and worm wheel to reduce friction, then efficiency is improved, but thermal expansion differences cause increased wear and jamming
Solution Approach 1:
The invention addresses the thermal expansion issue by making the receiving unit of the worm shaft movable relative to the worm wheel's receiving unit. This allows the system to accommodate the different thermal expansion characteristics of dissimilar materials (such as steel worm shaft and bronze worm wheel) while maintaining the friction-reducing benefits of material differentiation. The pre-stressing mechanism compensates for thermal effects, preventing jamming while preserving the efficiency gains from using optimally matched materials.
3Reliability
If a fixed clearance is used to accommodate manufacturing tolerances, then reliability is improved, but device complexity increases due to adjustment requirements
Solution Approach 1:
The invention replaces complex adjustable clearance mechanisms with a simpler dynamic pre-stressing system. By making the worm shaft's receiving unit movable along guide pins and applying pre-stressing, the system automatically accommodates manufacturing tolerances without requiring complex adjustment mechanisms. This reduces device complexity while maintaining the reliability benefits of tolerance compensation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The adjustable pre-stressing mechanism reduces wear and friction, enabling precise operation and adaptability to changing temperatures and loads, enhancing the worm drive's efficiency and suitability for precise adjustment applications.
Implementation Method 1
a spring element (10) is arranged at a second end (8) of the guide pin between the first receiving unit and a fastening means
Implementation Method 2
guide pins (6) for detachably connecting the first receiving unit to the second receiving unit
Data Source
AI summary
The invention relates to a worm drive comprising a worm shaft and a first receiving unit. The worm shaft is rotatably mounted in the first receiving unit. Furthermore, the worm drive comprises a worm wheel and a second receiving unit. The worm wheel is rotatably mounted in the second receiving unit. The first receiving unit is arranged on the second receiving unit and the rotatably mounted worm shaft is in contact with the worm wheel of the second receiving unit in order to transmit a torque. Furthermore, the worm drive comprises guide pins for detachably connecting the first receiving unit to the second receiving unit. More particularly, the first receiving unit receives at least part of the guide pins and the second receiving unit is connected to one of the guide pins, preferably to a first end of the guide pin. A spring element is arranged on a second end of the guide pin between the first receiving unit and a fastening means.