Electric Linear Actuator Common Raceway Disk Assembly
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Solution Overview
Problem
The existing electric linear motion actuators for brake systems face challenges in assembly complexity and cost due to the need for multiple components and machining processes, leading to increased assembly time and potential misplacements of thrust roller bearings.
Innovation Solution
The electric linear motion actuator incorporates a common annular raceway disk or uses the inner surface of a disk as a common raceway, reducing the number of components and employing press-fitting of pillar members into connection holes formed through plastic working or sintering, which simplifies assembly and eliminates the need for machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate raceway disks and thrust roller assemblies are mounted to each planetary roller shaft, then the thrust loads are supported and planetary rollers are rotatably supported, but the assembly process becomes complex and time-consuming with potential for component misplacements
Solution Approach 1:
The patent combines multiple separate components (individual raceway disks and thrust roller assemblies for each planetary roller) into a single integrated thrust roller bearing assembly. This unified structure supports all planetary rollers simultaneously, reducing the number of parts to be assembled and eliminating the risk of misplacement while maintaining reliable thrust load support.
Solution Approach 2:
The single thrust roller bearing assembly serves multiple functions: it supports thrust loads from all planetary rollers, provides rotational support for each planetary roller shaft, and acts as a unified mounting structure. This multi-functional design replaces what previously required multiple separate components, simplifying the overall assembly.
2Stability of the object's composition
If bolts and threaded holes are used to assemble the carrier, then the disks are retained at a predetermined distance, but the assembly time increases and machining costs increase
Solution Approach 1:
The patent replaces the mechanical fastening system (bolts and threaded holes requiring machining) with a press-fit system. The connection holes are formed directly in the disks through plastic working or sintering processes, eliminating the need for separate machining operations and bolt assembly, thereby increasing assembly speed while maintaining stable disk positioning.
3Manufacturing precision
If connection holes are formed by machining, then accurate positioning is achieved, but manufacturing costs increase
Solution Approach 1:
The patent changes the manufacturing method from mechanical machining to plastic working or sintering processes. These alternative processes form connection holes directly in the disks without requiring complex machining operations, reducing manufacturing costs while maintaining the necessary accuracy for proper pillar member fit and disk positioning.
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
This configuration significantly reduces assembly time, prevents component misplacements, and lowers costs by simplifying the assembly process and enhancing the durability of the carrier through heat treatment and accurate positioning of components.
Implementation Method 1
due to the frictional contact of the planetary rollers with the rotary shaft, the planetary rollers rotate about their axes while revolving around the rotary shaft
Implementation Method 2
thrust roller and retainer assemblies each mounted between one of the planetary rollers and a surface of the first disk that is opposed to the one of the planetary rollers such that thrust loads applied to the planetary rollers are supported by the respective thrust roller and retainer assemblies
Data Source
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AI summary
An electric linear motion actuator is provided which includes an outer ring member (21), a rotary shaft (34), planetary rollers (49), and a carrier (40) including a disk (41a), and in which the outer ring member (21) is formed on its inner diameter surface with a helical rib (51), and each of the planetary rollers (49) is formed in its outer diameter surface with circumferential grooves (52) in which the helical rib (51) is engaged. When the rotary shaft (34) rotates, due to the frictional contact of the planetary rollers (49) with the rotary shaft (34), the planetary rollers (49) rotate about their axes while revolving around the rotary shaft (34) so that the outer ring member (21) axially linearly moves. The electric linear motion actuator further includes thrust roller and retainer assemblies (53) each mounted between one of the planetary roller (49) and the surface of the disk (41a) of the carrier (40) that is opposed to the one of the planetary rollers, and each guided by a raceway (49a), i.e., an end surface of the corresponding planetary roller (49). The electric linear motion actuator further includes a common raceway disk (57) common to all of the thrust roller and retainer assemblies (53), the common raceway disk being mounted between the thrust roller and retainer assemblies (53) and the surface of the disk of the carrier that is opposed to the thrust roller and retainer assemblies. Therefore, the number of components constituting such a thrust roller bearing can be reduced, and the carrier (40) can be easily assembled.