Hydrostatic Linear Drive with 3-Face Cylinder Mode Switching
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Solution Overview
Problem
Hydrostatic linear drive systems face limitations in achieving high retraction and extension speeds in rapid mode while maintaining high forces in power mode, with increased energy consumption and complex constructions due to the need for multiple valves and pretensioned equalizing tanks.
Innovation Solution
The system employs separate hydraulically active faces for rapid mode, independent of the larger active face used in power mode, with hydraulic fluid displacement to an open equalizing tank, and mechanical coupling between single-action and synchronous cylinders to reduce resistance and energy consumption, featuring a compact design with a 3-face cylinder integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pretensioned equalizing tank is used to compensate for volume changes in the differential cylinder, then the hydraulic circuit can maintain pressure stability, but the system complexity increases due to additional valves and components
Solution Approach 1:
The patent extracts the pretensioning function from a separate equalizing tank and integrates it directly into the main cylinder chamber. The chamber serves dual purposes: as the main working chamber and as the equalizing tank with pretensioning capability, eliminating the need for separate equalizing tank components and valves
Solution Approach 2:
The patent merges the main cylinder chamber and the equalizing tank into a single integrated chamber. The chamber combines the functions of both the main working chamber and the equalizing tank, reducing system complexity while maintaining pressure stability through the integrated pretensioning mechanism
2Reliability
If the equalizing tank is constructed as a second differential cylinder, then volume compensation is achieved, but high displacement speeds in rapid mode cannot be produced due to counter-resistance
Solution Approach 1:
The patent removes the second differential cylinder construction and extracts the equalizing tank function to be integrated directly into the main cylinder chamber, eliminating the counter-resistance issue that prevented high displacement speeds
Solution Approach 2:
By merging the equalizing tank function into the main cylinder chamber, the system eliminates the mechanical coupling resistance between two separate differential cylinders, enabling high displacement speeds in rapid mode while maintaining volume compensation capability
3Adaptability or versatility
If two 2/2-way valves are used to control rapid and power modes, then mode switching is enabled, but the device complexity increases
Solution Approach 1:
The patent extracts the mode control function from multiple 2/2-way valves and implements it through a single valve that controls the connection between the main cylinder chamber and the equalizing tank, reducing the valve quantity while maintaining mode switching capability
Solution Approach 2:
The single valve in the invention serves multiple functions: it controls both rapid mode and power mode operation, and manages the connection between the main cylinder chamber and the equalizing tank, replacing the functionality of multiple specialized valves
4Reliability
If the annular piston face is smaller than the piston face in the differential cylinder, then volume compensation is possible, but the cylinder chamber volume is reduced
Solution Approach 1:
The patent merges the equalizing tank volume with the main cylinder chamber volume, creating a larger integrated chamber that provides both the necessary volume compensation capability and increased total volume for fluid storage and operation
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
This configuration allows for higher retraction and extension speeds in rapid mode, increased forces in power mode, and reduced energy consumption, resulting in a simpler and more efficient linear drive system with improved dynamics and energy savings.
Implementation Method 1
The hydraulic pump provides a changeable volume flow of a hydraulic fluid in a closed hydraulic circuit which comprises a first differential cylinder as a main cylinder
Implementation Method 2
This excess pressure is produced in a manner known per se by a pretensioning source
Implementation Method 3
In order to compensate for the different volumes of the differential cylinder when it is moved in the retraction and extension direction, the drive system requires an equalizing tank
Implementation Method 4
A 2/2-way valve is arranged in the connection line between the annular space of the second cylinder which functions as an equalizing tank and the annular space of the main cylinder
Data Source
AI summary
A linear drive system, in particular for a closure unit of a blow mold installation, with a simpler and more compact structure, a higher retraction and expansion speed in rapid mode, higher forces in power mode, and reduced energy consumption, than the prior art includes a cylinder arrangement which brings about a retraction and extension movement in rapid mode by separate hydraulically active faces which are independent of a larger hydraulically active face which is acted on with pressurized hydraulic fluid only in power mode. During the extension movement in power mode, however, the hydraulically active faces cooperate which contributes to high forces with a compact structure of the drive system.