Multi-Bush Shifter Structure for Speed Reducer Gear Engagement
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Solution Overview
Problem
Existing speed reducers face challenges in maintaining reliable engagement and preventing heat generation and abrasion due to surface contact between the bush and shifter, especially under increased load conditions, which can lead to operational failures in large machines.
Innovation Solution
A speed reducer design featuring a shifter with an annular groove for multiple bushes that can swing individually, allowing them to press the shifter in a direction parallel to the axis, thereby increasing the load capacity while maintaining engagement reliability through surface contact management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single bush presses the shifter in point contact or linear contact, then the structure is simple, but the load capacity is insufficient and heat generation occurs under increased transmission power
Solution Approach 1:
The single bush is segmented into multiple bushes (at least two) that are arranged circumferentially around the shifter. Each bush presses the shifter at a different location, distributing the contact from point/linear contact to surface contact. This segmentation increases the load capacity and reduces heat generation by spreading the pressure over a larger area, while maintaining reasonable structural complexity through the use of multiple simpler components.
2Reliability
If the bush presses the shifter with increased force to prevent disengagement, then engagement reliability improves, but heat generation and abrasion increase due to surface contact
Solution Approach 1:
By dividing the pressing function into multiple bushes arranged circumferentially, the total pressing force is distributed across multiple contact surfaces. This reduces the pressure intensity at each contact point while maintaining the total engagement reliability, thereby reducing heat generation and abrasion per unit area.
Solution Approach 2:
The pressing action is transitioned from a single-point or linear contact in one dimension to a distributed surface contact across multiple dimensions by arranging bushes circumferentially around the shifter. This dimensional expansion of the contact area reduces the harmful effects of friction and heat while maintaining reliability.
3Object-affected harmful factors
If the bush is made larger to increase surface contact area, then heat generation and abrasion are suppressed, but the device size and complexity increase
Solution Approach 1:
Instead of enlarging a single bush, the contact surface area is increased by segmenting the system into multiple smaller bushes arranged circumferentially. This achieves the same total contact area effect without increasing the radial size of individual components, thus avoiding an increase in overall device volume while suppressing heat generation and abrasion.
Data Source
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AI summary
Provided is a speed reducer (1) capable of reliably reducing and changing speed while suppressing heat generation and abrasion. The speed reducer (1) includes: a plurality of gears (7, 8) rotatably supported on an output shaft; a shifter (15) engageable with an engagement gear selected from the plurality of gears (7, 8) to couple the engagement gear to the output shaft (6); and a plurality of bushes (17) disposed in an annular groove (15f) formed in the shifter (15) to move the shifter (15) to the engagement gear and thereby engage the shifter with the engagement gear; and a bush support (16, 17) supporting the plurality of bushes (17) so as to allow them to swing individually.