Pressure Adjustment Unit Positioning to Prevent Shaft Scraping
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Solution Overview
Problem
Existing pressure adjustment units for liquid ejecting heads face issues where the distal end of the shaft portion may come into contact with the valve seat and get scraped during assembly, leading to inaccuracies and potential damage.
Innovation Solution
A pressure adjustment unit design featuring a valve body with a base end portion and a shaft portion, where the base end portion is housed in a first chamber and the shaft portion protrudes, with an elastic member and a casing having a partition wall and an annular first wall that defines the first chamber, ensuring the base end portion is accurately positioned before the shaft is inserted, preventing contact with the valve seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the shaft portion is inserted into the through hole to assemble the pressure adjustment unit, then the valve body is positioned in the first chamber, but the distal end of the shaft portion may come into contact with the valve seat and get scraped
Solution Approach 1:
The patent applies preliminary action by providing a positioning region on the outer periphery of the base end portion that engages with the inner periphery of the first wall before the shaft portion is inserted into the through hole. This preliminary positioning ensures the valve body is correctly located in the first chamber, preventing the distal end of the shaft portion from contacting and scraping the valve seat during assembly.
2Ease of operation
If the shaft portion is inserted into the through hole, then the valve body can be positioned, but contact with the valve seat causes damage and reduces reliability
Solution Approach 1:
The patent introduces an intermediary mechanism - the positioning region formed by the interaction between the outer periphery of the base end portion and the inner periphery of the first wall. This intermediary positioning structure prevents direct contact between the shaft portion and the valve seat, thereby protecting the shaft portion from damage and maintaining system reliability.
3Manufacturing precision
If proper positioning is provided to prevent shaft contact with valve seat, then assembly accuracy improves, but device structure becomes more complex
Solution Approach 1:
The patent applies universality by designing the base end portion to serve multiple functions: it provides structural support for the valve body, enables positioning through engagement with the first wall via the positioning region, and prevents shaft contact with the valve seat. This multi-functional design achieves improved assembly accuracy without significantly increasing device 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
This design effectively prevents the shaft portion from contacting the valve seat, enhancing assembly accuracy and reducing the risk of damage, while also improving sealing properties and reducing pressure loss.
Implementation Method 1
a valve body (90) that has a base end portion (92) housed in the first chamber (53), a shaft portion (91) protruding in the first direction (D1) from the base end portion (92), and an elastic member (93) provided on a first direction side of the base end portion (92)
Data Source
AI summary
A pressure adjustment unit includes a valve body including a base end portion, a shaft portion protruding in a first-direction from the base end portion, and an elastic member, and a casing that has a partition wall formed with a through hole into which the shaft portion is inserted, and a first-wall protruding in a second-direction opposite to the first-direction to define the first-chamber. On a first-chamber side of the partition wall, a valve seat, which is annular, is provided around the through hole to block a flow path by contacting with the elastic member, an outer periphery of the base end portion has a positioning region, and a distance between a first-direction-side end portion of the positioning region and a first-direction-side distal end of the shaft portion is shorter than a distance between the valve seat and a second-direction-side end portion of the first-wall.