Cylindrical Partitioning Member for Lash Adjuster Stability
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Solution Overview
Problem
Conventional lash adjusters face challenges in stabilizing the partitioning member within the plunger, particularly in small-sized designs, due to reduced press-fit allowances and potential air entrainment in the high-pressure chamber, which affects the hydraulic fluid level.
Innovation Solution
A lash adjuster design featuring a tubular partitioning member with an oil-passage defining portion opposite a recessed groove, allowing for improved flexibility and stable fixation without complex machining, and an enlarged press-fit region to enhance assembly and prevent direct communication between the oil passage and high-pressure chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vertical dimension of the oil passage is increased, then air entrainment is prevented, but the press-fit allowance is reduced
Solution Approach 1:
The invention transitions from a conventional stepped partitioning member to a cylindrical partitioning member that extends uniformly in the vertical direction. This dimensional change allows the oil passage end to be positioned above the oil passage hole without creating steps, thereby preventing air entrainment while maintaining adequate press-fit allowance throughout the partitioning member's length.
2Volume of moving object
If the partitioning member is made smaller to fit small-sized lash adjusters, then device size is reduced, but fixation stability is compromised
Solution Approach 1:
By changing the partitioning member from a stepped structure to a uniform cylindrical structure, the invention maintains adequate press-fit surface area even in small-sized applications. The cylindrical form ensures consistent dimensional relationships that preserve fixation stability while allowing the overall device size to be reduced.
3Manufacturing precision
If a stepped structure is used in the partitioning member, then oil passage positioning is improved, but device complexity increases
Solution Approach 1:
The invention extracts the stepped structure from the partitioning member, eliminating the complexity of multiple levels and transitions. The oil passage positioning function is achieved through the cylindrical form and oil passage end positioning above the oil passage hole, rather than through stepped geometry, thereby simplifying the overall structure.
4Stability of the object's composition
If complex machining is applied to the partitioning member, then fixation stability is improved, but manufacturing cost increases
Solution Approach 1:
The cylindrical partitioning member can be manufactured using simple turning or drawing processes without requiring complex stepped geometry. This dimensional simplification reduces manufacturing steps and costs while maintaining adequate press-fit fixation through the uniform cylindrical form that extends sufficiently into the plunger.
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 design ensures stable fixation of the partitioning member, increased low-pressure chamber capacity, reduced manufacturing costs, and improved applicability to small-sized lash adjusters by eliminating the need for special structures and complex machining.
Implementation Method 1
The plunger is moved up and down according to oil pressure in the high-pressure chamber. The hydraulic fluid in the low-pressure chamber in the plunger is drawn through the valve hole into the high-pressure chamber
Implementation Method 2
The partitioning member includes a lower part having a press-fit part press-fitted with an inner periphery of the lower peripheral wall of the plunger
Data Source
AI summary
A lash adjuster includes a plunger having a bottom wall with a valve hole and a peripheral wall having an oil passage hole and an inner periphery formed with a recessed groove, the plunger defining a high-pressure chamber between the bottom wall and a body, and a partitioning member having an oil passage end located above the oil passage hole. The partitioning member has an oil-passage defining portion located opposite the recessed groove and defining an oil passage between itself and a groove face of the recessed groove. The partitioning member defines a low-pressure chamber reserving a hydraulic fluid flowing through the oil passage hole, the oil passage and the oil passage end. The low-pressure chamber causes the reserved hydraulic fluid to flow through the valve hole into the high-pressure chamber. The partitioning member is formed into a cylindrical shape and extends in an up-down direction without any stepped part.