Internally-Driven Press Assembly with Nested Roller Screws
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Solution Overview
Problem
Existing presses that require large forces for mechanical fabricating operations are often cumbersome and prone to issues like leakage and durability problems, limiting their commercial application, especially when trying to achieve a balance between size and force generation.
Innovation Solution
A press assembly incorporating an elongated guide, a ram with an internal chamber, and a spindle with planetary roller screws that convert rotary motion into axial displacement, ensuring the ram and cylinder move in unison while preventing rotational and axial movement, allowing for a compact design capable of generating high forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large force is required to perform the desired fabrication operation, then the press can perform high-force operations, but the press becomes unduly large and cumbersome
Solution Approach 1:
The roller screws are nested within the cylindrical bore of the cylinder, with multiple roller screws arranged concentrically around the central axis. This nesting arrangement allows the press to generate high force through the mechanical advantage of the threaded mechanism while maintaining a compact overall size, as the force-generating components are contained within the cylinder's internal volume rather than requiring external space
2Volume of moving object
If smaller presses are used to reduce size, then the press is less cumbersome, but the press cannot generate sufficient force for the desired fabrication operation
Solution Approach 1:
The invention changes the mechanical parameters of the press by introducing a threaded interaction mechanism between the roller screws and the cylindrical bore. The thread geometry (pitch, angle, and profile) allows a small rotational movement of the roller screws to be converted into a large axial force on the ram, enabling compact press dimensions while maintaining high force output capability
3Force
If conventional press designs are used to achieve high force, then the desired force can be generated, but the press suffers from leakage and durability problems
Solution Approach 1:
The invention extracts and eliminates the traditional piston-cylinder hydraulic or pneumatic system that is prone to leakage. Instead, it uses a purely mechanical threaded mechanism where roller screws rotate within a cylindrical bore to directly drive the ram axially. This extraction of the fluid-based actuation system removes the source of leakage problems while maintaining the ability to generate high forces through the mechanical advantage of the thread geometry
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 press assembly effectively performs operations like piercing, punching, and welding with high force while maintaining a compact size, enhancing durability and reducing leakage issues, thus overcoming the limitations of previous designs.
Implementation Method 1
Roller screws may be planetary roller screws that may be rotatable about the externally-threaded driven end region. Rotation of the planetary roller screws about the externally-threaded driven end region may produce the axial displacement of the cylinder and the ram.
Data Source
AI summary
A press assembly includes an elongated guide, and a ram that is at least partially mounted to the elongated guide and axially movable relative to the elongated guide. A fabricating tool is disposed at an outboard end portion of the ram. The ram including an internal chamber. A cylinder is disposed within an internal chamber of the ram and is secured to the ram such that the cylinder is fixed relative to the ram axially and rotationally so that the cylinder and ram move in unison. A spindle having a driving end region and a driven end region opposite the driving end region is disposed at least partially within a cylindrical bore of the cylinder. A motor is adapted to rotate the driving end region of the spindle to effect an axial displacement of the cylinder and the ram.