Driving Tool Seal Lip Bending for Air Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing driving tools with head valves that close the exhaust passage after the supply passage is opened face issues with air leakage due to dimensional management challenges and increased slide resistance when closing the seal, leading to energy loss and delayed discharge.
Innovation Solution
A driving tool design featuring a seal portion with a lip portion protruding along the outer circumference of the head valve, which generates an air pressure difference to bend and contact the valve, ensuring the exhaust passage is sealed after the supply passage is opened, reducing air leakage and maintaining low slide resistance even with slight dimensional changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the exhaust passage is closed after the supply passage is opened, then the timing when the supply passage is opened can be set close to the timing when the exhaust passage is closed, but compressed air leaks from the exhaust passage and air consumption amount is increased
Solution Approach 1:
The patent employs a rubber seal member with elastic properties that can deform to seal the exhaust passage. The elastic seal member is pressed against the head valve inner wall surface by spring force, creating a flexible sealing mechanism that adapts to dimensional variations while preventing air leakage during the transition period between supply passage opening and exhaust passage closing.
Solution Approach 2:
The exhaust passage is closed in advance before the supply passage is fully opened. The head valve structure is designed so that the exhaust passage closing action occurs preliminarily, creating a buffer period where the supply passage is still closing while the exhaust passage is already sealed, thereby preventing air leakage.
2Loss of energy
If the supply passage is opened after the exhaust passage is closed, then air leakage is prevented, but slide resistance in the seal portion is increased causing response delay and energy loss
Solution Approach 1:
The patent changes the physical parameters of the seal member by using an elastic rubber material with specific hardness (40-70 degrees JIS A) and dimensions. This parameter optimization allows the seal member to maintain low slide resistance during head valve movement while ensuring adequate sealing force when pressed against the head valve surface, thus preventing air leakage without causing response delay.
Solution Approach 2:
The seal member is designed with elastic properties that allow it to dynamically adapt during head valve movement. The spring force dynamically presses the seal member against the head valve, providing variable sealing pressure that maintains low friction during motion while ensuring tight sealing when the valve is in position, thereby preventing air leakage without increasing response time.
3Reliability
If a rubber seal member contacts the inner wall surface of the head valve, then airtightness can be secured, but dimensional management must be severe as rubber dimensions change with production error or temperature change
Solution Approach 1:
The rubber seal member's flexibility and elasticity allow it to compensate for dimensional variations in both the seal member itself and the head valve mating surface. The elastic material can deform to maintain contact and sealing effectiveness even when there are production tolerances or thermal expansion differences, eliminating the need for severe dimensional management while ensuring reliable airtightness.
Solution Approach 2:
The spring mechanism automatically adjusts the sealing pressure of the rubber seal member against the head valve. This self-adjusting feature compensates for dimensional changes in the rubber due to temperature or production variations, maintaining consistent sealing force without requiring precise dimensional control during manufacturing.
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 effectively suppresses compressed air leakage and maintains smooth operation by delaying the opening of the supply passage, reducing energy loss and ensuring airtightness without severe dimensional management, while preventing increased slide resistance.
Implementation Method 1
an air pressure difference is generated between an inside and an outside of the lip portion, and the lip portion is bent in a direction of contacting the outer circumferential surface of the head valve
Data Source
AI summary
A driving tool including a driver configured to drive out a fastener, a piston to which the driver is connected, a cylinder in which the piston is disposed so as to be reciprocated, a head valve which is slidably mounted to an outer circumferential side of the cylinder and controls a flow of compressed air into the cylinder, and a seal portion which is provided to face an opening edge of the head valve. The seal portion includes a lip portion protruding along an outer circumferential surface of the head valve.