Selectable One-Way Clutch Strut Erection Angle Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing selectable one-way clutches face issues with increased dimension due to larger hydraulic piston stroke and strut abrasion caused by collisions with the notch plate during rotation, leading to reduced durability.

Innovation Solution

The design incorporates a pocket plate with accommodating recessed portions, a rotatable notch plate with engagement recessed portions, and a cover plate with through-holes allowing engagement pieces to project and engage with the notch plate, reducing the stroke amount of the hydraulic piston and preventing collisions, thus enhancing durability by reducing the erection angle and contact with the cover plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the strut completely projects from the cover plate with a greater erection angle, then the engagement surface can engage with the engagement recessed portion, but the stroke amount of the hydraulic piston becomes greater, increasing the dimension of the selectable one-way clutch

Engineering Contradiction:
Improveengagement capabilityVSAvoidstroke amount of hydraulic piston
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent changes the geometric parameters of the engagement piece, specifically adding a projecting portion that contacts the cover plate to reduce the erection angle. This parameter change allows the engagement surface to still engage with the engagement recessed portion while reducing the stroke amount of the hydraulic piston, thereby resolving the contradiction between engagement capability and piston stroke length.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If the notch plate stays close to the pocket plate, then the overall dimension is reduced, but the strut collides against the notch plate in rotation during disturbance, causing abrasion and deteriorating durability

Engineering Contradiction:
Improveaxial distance between platesVSAvoiddurability of strut
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent extracts the harmful collision function by changing the geometric configuration of the engagement piece. The projecting portion that contacts the cover plate prevents the engagement surface from colliding with the notch plate during rotational disturbance, thereby maintaining close axial distance between plates while preserving strut durability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the erection angle of the strut is greater, then the engagement surface can effectively engage with the engagement recessed portion, but the stroke amount increases requiring a larger hydraulic chamber

Engineering Contradiction:
Improveengagement effectivenessVSAvoidhydraulic chamber volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent modifies the geometric parameters by introducing a projecting portion on the engagement piece that contacts the cover plate. This changes the erection angle parameter to a smaller value, which reduces the required stroke amount of the hydraulic piston and consequently reduces the hydraulic chamber volume while maintaining effective engagement.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3404279B1Selectable one-way clutch
Publication Date: 2019.12.18 TOYOTA JIDOSHA KK
  • EP3404279B1 patent drawingFigure 1
  • EP3404279B1 patent drawingFigure 2~3
  • EP3404279B1 patent drawingFigure 4

AI summary

The selectable one-way clutch (1) includes a pocket plate (2), a notch plate (3), a cover plate (4), and plate-like struts (5). A one end portion (51) of each strut (5) is provided with an engagement surface (51a) and a projecting portion (51b). Each strut (5) comes into an erect state in which the engagement surface of the strut erects from the other surface (4b) of the cover plate (4) toward the notch plate side. The selectable one-way clutch (1) moves the notch plate (3) in the axial direction to change a distance in the axial direction between the pocket plate (2) and the notch plate (3), thereby carrying out switching between an out-of-engagement state in which the erecting struts (5) cannot contact with the notches (31) and a one-way clutch state in which the erecting struts (5) can contact with the notches.