Piston Rod Cylinder Structure for Three-Stage Position Detection
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Solution Overview
Problem
Existing cylinder devices face challenges in detecting the position of an output member due to the formation of a second valve chamber, which makes it difficult to apply to small-sized devices.
Innovation Solution
A cylinder device with a mechanism that detects the position of an output member in three stages using the outer periphery of a piston rod and the inner wall of a housing, incorporating a supply passage, discharge passage, and pressure loss passage with specific regions for seal members and loose insertion regions to allow for precise position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a second valve chamber is formed by hollowing the output member with a valve rod inserted, then position detection function is achieved, but the device size increases and cannot be applied to small-sized cylinder devices
Solution Approach 1:
The patent combines the position detection function with the existing cylinder structure by utilizing the outer periphery of the piston rod and the inner wall of the housing, merging multiple functions into a compact integrated design rather than adding separate hollow chambers and valve rods
Solution Approach 2:
The invention transitions from a volumetric detection approach (hollow chamber) to a linear dimensional approach (sliding regions along the piston rod trajectory), enabling position detection through linear displacement rather than volumetric measurement
2Reliability
If sliding regions with tight fit are provided for seal function, then sealing performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies different local qualities to different regions of the housing inner wall: sliding regions have tight fits for sealing while loose insertion regions have larger clearances, allowing each region to be optimized for its specific function without requiring uniform high precision throughout
Solution Approach 2:
The inner wall is segmented into multiple functional regions (sliding regions and loose insertion regions) with different dimensional tolerances, dividing the structure into zones with different precision requirements based on their specific functions
3Measurement precision
If multiple loose insertion regions are provided for three-stage position detection, then position detection capability is enhanced, but device complexity increases
Solution Approach 1:
The compressed gas system serves multiple functions: it provides both the driving force for the piston and the medium for position detection through pressure changes, eliminating the need for separate detection systems and reducing overall 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
Enables miniaturization of the cylinder device by allowing for three-stage position detection of the output member, enhancing its applicability to smaller designs.
Implementation Method 1
sliding regions each having an inner diameter such that the seal member makes contact therewith to effectively enable a seal function
Implementation Method 2
a supply passage for supplying compressed gas inside the hollow inner wall
Implementation Method 3
a pressure loss passage for allowing the compressed gas supplied inside the hollow inner wall to pass through with a pressure loss larger than that of the supply passage and the discharge passage
Data Source
Figure 1A~1D
Figure 2A~2B
Figure 3
AI summary
Provided is a cylinder device provided with a mechanism for detecting, in three stages, the position of an output member by using the outer periphery of a piston rod of the output member, and the inner wall of a housing. A housing (2) is provided with an A passage (Ap) for supplying compressed gas, and a B passage (Bp) for discharge to the atmosphere. A piston rod (3) is provided with a projection (12 a) that pulls and pushes down the seal member (11) together with an annular valve member (10). The hollow inner wall inside the housing is provided with: a sliding region (13) having an inner diameter such that a seal member (11a) makes contact therewith to effectively enable the seal function; , a loose insertion region (14) having a great inner diameter such that the sealing function of the seal member (11a) does not work at all; and a valve member region (18) which has a great inner diameter such that the annular valve member (10) can move up/down, and which stores the annular valve member (10) while the upper side is surrounded by a ring surface (2d), the valve member region communicating with the B passage (Bp).