Piston Unit Half-Shell Assembly for Plunger Cylinder
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing piston units for plunger cylinders face challenges with costly and labor-intensive connections between the guide piston and piston rod, leading to increased repair and maintenance costs due to non-detachability and complex assembly processes.
Innovation Solution
A piston unit design featuring a piston rod with a concave receiving contour and half-shells that form a form-fitting connection, allowing for easy assembly and secure positioning without the need for additional tools, using a receiving contour and engagement section that enables pivoting and secure axial fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the guide piston is pressed onto or welded to the piston rod, then a secure connection is achieved, but the assembly becomes non-detachable and requires additional work
Solution Approach 1:
The guide piston is divided into two separate half-shells that can be independently positioned and secured to the piston rod. This segmentation allows for tool-free assembly by simply placing the half-shells at the desired position, while still achieving a secure connection that prevents detachment during operation.
Solution Approach 2:
The half-shells are pre-positioned at the desired location on the piston rod before the piston unit is inserted into the plunger cylinder. This preliminary positioning ensures that no additional tools or assembly steps are needed during final installation, as the half-shells are already in their correct positions and will be automatically secured when the piston rod is inserted.
2Ease of operation
If the guide piston is formed by two half-shells, then assembly and disassembly become simpler, but additional devices or personnel are required to secure the half-shells
Solution Approach 1:
The half-shells are designed to self-secure to the piston rod through their own structural features without requiring external securing devices, tools, or additional personnel. The half-shells inherently maintain their position on the piston rod through their geometric design, eliminating the need for separate securing mechanisms.
3Reliability
If the guide piston or piston rod is damaged, then the entire piston unit must be replaced, but this increases repair and maintenance costs
Solution Approach 1:
The guide piston is segmented into two half-shells that can be independently removed and replaced. If only one half-shell is damaged, only that specific half-shell needs to be replaced rather than the entire guide piston or piston unit, significantly reducing repair costs and simplifying maintenance operations.
4Ease of manufacture
If the half-shells are arranged on the piston rod before insertion, then simple assembly is achieved, but the half-shells must be secured against undesired detachment
Solution Approach 1:
The half-shells are pre-positioned on the piston rod at the desired location before the piston unit is inserted into the plunger cylinder. This preliminary arrangement allows for rapid assembly without requiring tools or additional steps during installation, as the half-shells are already in their final positions and will be automatically secured when the piston rod is inserted into the cylinder tube.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a piston unit (1) of a plunger cylinder (2), comprising a piston rod (3) with a cylinder-bottom end section and a guide-side end section, and a guide piston (4) formed by a first half-shell (5) and a second half-shell (6), wherein the half-shells (5, 6) at least partially surround the piston rod (3). The piston rod (3) has a circumferential, concave receiving contour (7) in the region of the cylinder-bottom end section, wherein the receiving contour (7) in turn has an outer wall (8) on the cylinder bottom side, and wherein the outer wall (8) forms an acute angle α (alpha) with the longitudinal axis of the piston rod (3).The half-shells (5, 6) rest with their respective inner surface on an outer surface of the piston rod (3) and furthermore have corresponding end regions (9, 10 and 11, 12), wherein the end regions (9, 10) of the first half-shell (5) have a gripping offset relative to the opposite end regions (11, 12) of the second half-shell (6). In addition, each half-shell (5, 6) has an engagement section with an inner engagement contour (13, 14), wherein the respective engagement section forms the guide-side boundary of the associated half-shell (5, 6) and wherein the respective engagement contour (13, 14) is recessed relative to the inner surface of the associated half-shell (5, 6).According to the invention, the engagement contours (13, 14) of the associated half-shell (5, 6) engage in the receiving contour (7) of the piston rod (3), each engagement contour (13, 14) having an inner wall (15, 16) and the respective inner wall (15, 16) corresponding with the cylinder-bottom outer wall (8) of the receiving contour (7). Furthermore, each half-shell (5, 6), by means of its associated engagement contour (13, 14), encloses an angle greater than 180° in its first end region (9, 11) and in a section axially opposite the respective engagement contour (13, 14) in its second end region (10, 12).