Speed Reducer Restricting Member for Bearing Axial Stability

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Solution Overview

Problem

Eccentric oscillation speed reducers face issues with the bearing between the eccentric member and the external gear not being reliably restricted from moving in the axial direction, leading to potential malfunction or damage due to unintentional contact with surrounding components.

Innovation Solution

A speed reducer design incorporating a restricting member with an inner annular portion and an outer portion, where the inner annular portion is located on the shaft member and the outer portion is on the eccentric member, with varying distances from the center, effectively restricting the bearing's movement in the axial direction without touching surrounding components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the flange length in the radial direction is increased to restrict the bearing, then the bearing axial movement is restricted, but the flange extends beyond the bearing and may contact surrounding components causing malfunction

Engineering Contradiction:
Improvebearing axial position stabilityVSAvoidunintentional contact with surrounding components
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The restricting member is divided into an inner annular portion and an outer portion with different radial distances from the center. This segmentation allows each part to serve a specific function: the inner portion provides axial restriction while the outer portion's varying distance prevents it from extending beyond the bearing to contact surrounding components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The restricting member has non-uniform radial distance from the center at different positions on its outer edge. This local quality variation ensures that the restricting member effectively restricts the bearing axially while preventing contact with surrounding components at critical locations.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the center of the eccentric member is significantly shifted from the axis of rotation, then the eccentric oscillation function is improved, but the flange needs larger radial length which increases the risk of contacting surrounding members

Engineering Contradiction:
Improveeccentric oscillation performanceVSAvoidflange radial length
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The restricting member is segmented into portions with different radial distances from the center. This allows the structure to accommodate significant eccentric member displacement while maintaining compact radial dimensions, as each segment is optimized for its specific radial position.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The restricting member has an asymmetric design where the outer portion's distance from the center varies at different positions. This asymmetric configuration allows the structure to adapt to the eccentric oscillation motion while preventing excessive radial extension that would cause contact with surrounding members.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If a block plate with flange is used to restrict the bearing, then the bearing axial movement is restricted, but the structure complexity increases and may cause unintentional contact

Engineering Contradiction:
Improvebearing axial restrictionVSAvoidrestricting structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The restricting member is divided into an inner annular portion and an outer portion, creating a segmented structure that is simpler than a traditional block plate with flange. This segmentation achieves the same axial restriction function with reduced complexity and lower risk of unintentional contact.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts only the essential functional elements needed for axial restriction, eliminating the complex flange structure of traditional block plates. The restricting member achieves bearing restriction through its annular portions without requiring the elaborate flange design.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4417836A1Speed reducer and restraining member
Publication Date: 2024.08.21 NABTESCO CORP
  • EP4417836A1 patent drawingFigure 1
  • EP4417836A1 patent drawingFigure 2
  • EP4417836A1 patent drawingFigure 3

AI summary

A speed reducer (10) includes an external gear (40), a shaft member (50) having an eccentric member (55) for causing the external gear (40) to eccentrically oscillate, a bearing (15) disposed between the external gear (40) and the shaft member (50) and a restricting member (60). The restricting member (60) has an inner annular portion (70) and an outer portion (80). The inner annular portion (70) has an inner circumferential edge (61) located on the shaft member (50), and the outer portion (80) has an outer edge (62) with a distance from a center of the inner circumferential edge (61) to the outer edge (62) varying among different positions on the outer edge (62). The outer portion (80) restricts the bearing (15) from moving in an axial direction (D1).