Working Cylinder Thread-Weld Coupling for Lower Wall Thickness
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Solution Overview
Problem
Existing work cylinders, particularly screw cylinders, face challenges with material thickness and weight due to the need for thick walls to accommodate thread conversion and high axial forces from operating pressure, leading to increased material consumption and length dimensions.
Innovation Solution
A work cylinder design featuring a special coupling between the cylinder tube and closure parts, utilizing a common thread section and a ring welding seam to absorb axial forces, allowing for reduced material thickness and weight while maintaining reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cylinder tube wall thickness is increased to accommodate the subtractively machined thread and withstand axial forces, then the strength and reliability of the working cylinder is improved, but the material consumption and final weight increase significantly
Solution Approach 1:
The coupling between cylinder tube and closure part is segmented into two functional zones: a welded zone for force transmission and a threaded zone for sealing and positioning. The welded connection absorbs the majority of axial tensile forces, allowing the thread to be shallower and the wall thickness to be reduced while maintaining overall strength
Solution Approach 2:
The invention merges two connection methods (welding and threading) into a hybrid coupling system. The closure part is both welded to the cylinder tube and threaded into it, combining the high strength of welding with the sealing and positioning advantages of threading, thereby reducing the required wall thickness
2Reliability
If the tube wall thickness is increased to provide sufficient thread length for withstanding high axial forces, then the reliability of the screw connection is improved, but the overall dimensions and material usage increase
Solution Approach 1:
The connection function is segmented between the welded joint (for force absorption) and the threaded joint (for sealing and positioning). This segmentation allows the thread length to be significantly reduced since it no longer needs to bear the full axial load, thereby reducing the overall length of the cylinder tube while maintaining reliability
3Manufacturing precision
If the subtractive machining process is used to produce the thread on the cylinder tube, then the sealing and positioning accuracy is improved, but the material consumption increases due to the additional material thickness required
Solution Approach 1:
The hybrid coupling combines welding with threading, where the welded connection provides the primary force transmission path. This allows the threaded connection to use less material and shallower threads while still achieving the required sealing and positioning precision, thereby reducing material consumption
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 solution significantly reduces the axial tensile forces absorbed by the common thread section, allowing for thinner cylinder tube walls, reduced material consumption, and lower weight, while ensuring reliable force distribution between the ring welding seam and the common thread section.
Implementation Method 1
The closure element and the cylinder tube end are materially connected to one another in a close area of the axial ring contact surface by means of a circumferential ring weld which is produced by laser welding
Implementation Method 2
The external and internal threads form a common thread section in which they are engaged
Data Source
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AI summary
The invention relates to a working cylinder, having a cylinder (1) with a cylinder tube (3), and having a piston unit (2), wherein the cylinder (1) has a coupling portion (7a) which has a closure part (4a) and the cylinder tube end portion (5a), wherein the cylinder tube end portion (5a) has a cylinder tube threaded portion (51a), a cylinder tube intermediate portion (52a) and a cylinder tube end (53a), wherein the closure part (4a) has an external thread (8a) and the cylinder tube threaded portion (51a) has an internal thread (9a) corresponding to the external thread (8a), wherein the external thread (8a) and the internal thread (9a) form a common threaded portion which is designed to couple the closure part (4a) and the cylinder tube (3) with a form fit, wherein the cylinder tube end (5a) is connected to the closure part (4a) by integral bonding by means of an encircling annular weld seam (10a), wherein the annular weld seam (10a) is designed as a laser-produced annular weld seam and forms a sealing plane which is tight to pressure medium, wherein, in a operating state under load alleviation, the common threaded portion does not absorb an axial tensile force, and wherein, in the operating state under load, the annular weld seam (10a) and the common threaded portion each absorb an axial tensile force. The invention further relates to a method for the production of such a working cylinder.