Worm Gear Holder Fixing for Stable Backlash Adjustment
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Solution Overview
Problem
The existing mechanical devices with worm gear mechanisms face challenges in securely fixing the holder to the frame after backlash adjustment, as the frictional force applied to prevent rotation is insufficient to counteract vibrations during machining, leading to changes in the adjusted backlash.
Innovation Solution
A mechanical device with a position adjusting mechanism that includes a holder screwed into the accommodation hole, an axial force generation part using a screw member to exert an axial force in the axis line direction, and a base part to receive the reactive force, ensuring the holder is firmly fixed to the frame through a large frictional force generated over the entire circumference, with the screwing direction coinciding with the axis line direction for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a disk-shaped spacer is pressed against the outer peripheral portion of the holder by a screw mechanism, then the holder can be fixed to prevent rotation, but the frictional force is applied to only a portion of the outer peripheral surface, which is insufficient to counteract large vibrations during machining
Solution Approach 1:
The invention transitions from a two-dimensional contact (disk-shaped spacer pressing on the outer peripheral surface) to a three-dimensional engagement by screwing the holder into the accommodation hole. This dimensional change allows the frictional force to be distributed over the entire circumferential surface area of the holder within the accommodation hole, significantly increasing the total frictional force available to counteract vibrational forces during machining.
Solution Approach 2:
The invention changes the contact parameters by increasing the contact area from a localized disk-shaped spacer to the entire circumferential surface of the holder within the accommodation hole. This parameter change (increased contact area) directly increases the maximum static frictional force, enabling the holder to remain fixed during high-vibration machining operations.
2Ease of operation
If the holder is allowed to rotate for backlash adjustment, then the backlash can be adjusted by moving the worm shaft, but the holder cannot be securely fixed after adjustment to prevent changes in the adjusted backlash under vibration
Solution Approach 1:
The invention implements a dynamic fixing mechanism where the holder can rotate freely during the adjustment phase to enable backlash modification, and then transitions to a fixed state after adjustment by screwing the holder into the accommodation hole. This dynamic behavior allows the system to switch between operational modes (adjustment vs. fixed operation) as needed.
Solution Approach 2:
The invention performs the backlash adjustment operation before the final fixing action. The holder is first positioned and adjusted to the desired backlash setting while allowing rotation, and only after the adjustment is complete is the holder screwed into the accommodation hole to prevent further rotation. This preliminary adjustment followed by fixing ensures the desired backlash is achieved and maintained.
3Force
If the screwing direction of the axial force generation part coincides with the axis line direction, then the axial force is exerted effectively on the holder, but the structure becomes more complex with the need for an axial force generation part and base part
Solution Approach 1:
The invention makes the holder serve multiple functions: it acts as both the support for the worm shaft and the element that is screwed into the accommodation hole to provide fixing. The holder's outer peripheral surface serves as both the mounting surface for the worm shaft bearing and the engagement surface with the accommodation hole. This multi-functionality reduces the need for separate components while maintaining the required axial force generation.
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 solution securely fixes the holder to the frame, preventing rotation and maintaining the adjusted backlash, even under conditions of large vibrations, by generating a large frictional force that effectively counters rotational forces, ensuring precise backlash adjustment and stability.
Implementation Method 1
the frictional force acting between the set piece subjected to the pressing force by the screw mechanism and the portion of the outer peripheral surface of the rotary body to which the set piece is pressed
Implementation Method 2
a male screw is formed on an outer peripheral surface of the holder, a female screw is formed on an inner peripheral surface on the one end-side of the accommodation hole and the holder is provided in a state of being screwed (screw-fitted) in the accommodation hole
Data Source
AI summary
A mechanical device includes a worm gear mechanism which includes a worm wheel and a worm shaft. The worm gear mechanism adjusts backlash between the worm and the worm wheel by movement of the worm shaft in an axis line direction. The mechanical device includes a position adjusting mechanism which includes a holder, an axial force generation part and a base part. The holder is screwed into the accommodation hole and rotatably supports the worm shaft. The holder causes the movement of the worm shaft by rotation. The axial force generation part includes a screw part and exerts an axial force on the holder. The base part is provided to the frame and receives a reactive force acting on the axial force generation part as a result of exerting the axial force to the holder.