Piston Rod Position Sensing for Miniaturized Cylinder Assemblies
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cylinder devices face challenges in miniaturization due to the design of the mechanism for detecting the position of the output member, particularly when a second valve chamber is formed by hollowing the output member and a valve rod is protruded from the housing, making it difficult to apply to small-sized devices.
Innovation Solution
A cylinder device with a piston rod, seal members, and a hollow inner wall in the housing, featuring supply, discharge, and pressure loss passages, allowing for position detection using the outer periphery of the piston rod and inner wall, with sliding and loose insertion regions to enable seal functions in specific stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a second valve chamber is formed by hollowing the output member and a valve rod is protruded from the housing, 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 merges the position detection function with the existing piston rod and housing structure. The hollow inner wall of the housing serves as the detection chamber, and the piston rod itself becomes the moving element for detection, eliminating the need for separate hollowed output members and protruding valve rods.
Solution Approach 2:
The piston rod serves dual functions: driving the piston and serving as the moving element for position detection. The hollow inner wall of the housing serves multiple purposes including structural support and forming the detection chamber, reducing the need for additional dedicated components.
2Reliability
If sliding regions with tight fit are provided for seal function, then sealing performance is improved, but friction and wear increase
Solution Approach 1:
The patent applies different surface qualities to different regions of the piston rod. Sliding regions have tight fits for effective sealing, while loose insertion regions have larger clearances to reduce friction and wear. This local differentiation allows the system to achieve reliable sealing without excessive friction throughout the entire行程.
Solution Approach 2:
The interaction region between the piston rod and housing is segmented into multiple functional zones: sliding regions for sealing and loose insertion regions for low-friction movement. This segmentation allows each region to be optimized for its specific function without compromising the other.
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 position detection in three stages, facilitating the miniaturization of the cylinder device by utilizing the outer periphery of the piston rod and inner wall for precise pressure measurements.
Implementation Method 1
The hollow inner wall in the housing has sliding regions each having an inner diameter such that the seal member makes contact therewith to effectively enable a seal function
Implementation Method 2
The housing has 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
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 (12a) 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 large 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 large 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).