Variable Valve Timing Device Spring Assembly
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Solution Overview
Problem
Conventional valve timing varying devices face challenges such as increased complexity, cost, and difficulty in assembly due to a large number of components and intricate structures, which lead to vane rotor inclination, wear, and friction issues, while also failing to meet downsizing requirements.
Innovation Solution
A valve timing varying device with a two-divided housing rotor structure and a torsional coiled urging spring, where the spring's ends are positioned to facilitate easy assembly and reduce inclination, eliminating the need for additional components like fixed pins and bushings, and allowing for downsizing by accommodating the spring within the housing rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a three-divided housing rotor structure is used, then the device can accommodate the torsion spring, but the number of parts increases and assembly complexity increases
Solution Approach 1:
The patent merges the housing rotor into a two-divided structure consisting of a front housing member and a rear housing member, reducing the number of separate components compared to a three-divided structure. The torsion spring is integrated between these two members, eliminating the need for additional accommodation structures while maintaining spring functionality.
Solution Approach 2:
The torsion spring is extracted and positioned specifically between the front and rear housing members, allowing it to be easily accessible for assembly while not requiring a complex three-divided structure. This extraction places the spring in an optimal location that simplifies both the housing structure and the assembly process.
2Reliability
If the torsion spring is disposed inside the housing rotor with ends latched on both rotors, then the spring can function properly, but the assembly becomes difficult as the spring ends are not visible
Solution Approach 1:
The patent introduces a spring retainer as an intermediary component that holds the torsion spring in a predetermined state during assembly. This retainer allows the spring to be properly positioned and latched between the front and rear housing members while making the assembly process visible and controllable, solving the visibility and accessibility problem.
Solution Approach 2:
The torsion spring is preliminarily positioned and held in a specific state by the spring retainer before final assembly. This preliminary action ensures that the spring ends are correctly oriented and accessible for latching, making the subsequent assembly steps straightforward and reliable.
3Device complexity
If the housing rotor is made as a single integrated piece, then the structure is simplified, but the torsion spring becomes difficult to assemble
Solution Approach 1:
The housing rotor is segmented into a front housing member and a rear housing member, creating a natural opening through which the torsion spring can be installed. This segmentation maintains structural simplicity while providing easy access for spring assembly, avoiding the complexity of a three-divided structure.
Solution Approach 2:
The patent utilizes the axial dimension by positioning the torsion spring between the front and rear housing members along the rotation axis. This dimensional approach allows the spring to be easily assembled from the end of the housing rotor without requiring complex radial or circumferential access.
4Ease of manufacture
If additional components like fixed pins and bushings are used to support the spring, then the spring can be assembled, but the component count increases and downsizing is prevented
Solution Approach 1:
The front and rear housing members serve multiple functions: they provide structural support for the rotors, create the accommodating chamber, and directly support the torsion spring ends. This multi-functionality eliminates the need for separate fixed pins and bushings, reducing component count and enabling device downsizing.
Solution Approach 2:
The housing members are designed to directly latch and support the torsion spring ends without requiring additional intermediary components. The housing structure itself provides the necessary support and positioning functions, making the system self-sufficient and eliminating extra parts that would increase size and complexity.
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 prevents vane rotor inclination, reduces friction, simplifies assembly, and achieves cost reduction through reduced component count and device downsizing, ensuring a predetermined function while maintaining performance.
Implementation Method 1
a coiled torsion spring installed between the housing rotor and the vane rotor in order to rotation-urge the vane rotor toward an advanced side
Data Source
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AI summary
The valve timing varying device according to the present invention includes a housing rotor (20) composed of a front side housing member (22) and a rear side housing member (21), a vane rotor (30), and an urging spring (40) for rotationally urging the vane rotor in one direction with respect to the housing rotor. The urging spring (40) has a coil part (41), a first end (42) provided outside in a radial direction with respect to the coil part, and a second end (43) provided inside in the radial direction with respect to the coil part. The front side housing member (22) has a first latching concave part (22f) for latching the first end on an inside wall face. The vane rotor (30) has an accommodation concave part (35) for accommodating at least a part of the coil part at the front end side, and a second latching concave part (36) for latching the second end in an area facing an opening (22c). Therefore, wear and a friction force in a sliding area can be reduced and the assembling performance can be improved while achieving the size reduction of the device.