Expandable Hub Sensor Housing for Press Force Measurement
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Solution Overview
Problem
Existing press designs with force-measuring sensors suffer from issues such as radial force and bending moment-induced stress, requiring recalibration and complex cable routing, which can compromise measurement accuracy and increase production complexity.
Innovation Solution
A sensor housing with an expandable hub and central screw for secure radial attachment within a cavity, featuring a conical design for precise clamping and a through opening for cable routing, eliminating the need for additional recesses and reducing stress on the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If set screws are used to fasten the sensor housing to the press ram, then the sensor housing is securely attached, but radial forces and bending moments are generated that can falsify measurement values
Solution Approach 1:
The fastening function is segmented from the sensor housing body into a separate expandable hub mechanism. The hub is divided into expandable segments that can be independently actuated by the expansion element, allowing uniform radial expansion without creating bending moments on the sensor housing.
Solution Approach 2:
The expandable hub acts as an intermediary between the sensor housing and the press ram cavity wall. Instead of directly fastening the sensor housing with set screws, the expansion element expands the hub to create a friction-based interference fit against the cavity wall, eliminating direct mechanical fastening points that would create stress concentrations.
2Stability of the object's composition
If set screws are tightened to secure the sensor housing, then the attachment becomes stable, but recalibration is required after any loosening or repair
Solution Approach 1:
The expandable hub mechanism provides self-adjusting uniform pressure distribution through its expansion geometry. When the expansion element is actuated, the hub segments expand uniformly in all radial directions, automatically ensuring even force distribution without requiring manual adjustment or calibration procedures.
3Object-affected harmful factors
If a recess is provided in the press ram for cable routing, then the connecting cable can be protected from damage, but the production complexity increases and press ram strength is reduced
Solution Approach 1:
The expansion element serves multiple functions: it acts as both the fastening mechanism (expanding the hub against the cavity wall) and the cable protection feature (providing a through-opening for cable routing). This eliminates the need for separate recess structures in the press ram, reducing production complexity while maintaining cable protection.
4Strength
If set screws are used to fasten the sensor housing, then the sensor can be securely attached, but the tightening process can generate excessive transverse forces on the sensor housing
Solution Approach 1:
The fastening mechanism transitions from a static set screw system to a dynamic expansion process. The expansion element is actuated to progressively expand the hub, allowing controlled force application that distributes stress uniformly across the hub-cavity interface, avoiding sudden or concentrated transverse forces on the sensor housing.
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 design ensures bending moment-free assembly, eliminates the need for frequent recalibration, simplifies cable routing, and enhances measurement accuracy by providing a stable and adjustable clamping mechanism.
Implementation Method 1
an expanding element which is designed to expand the hub during a relative movement of the hub and expanding element along a longitudinal axis of the sensor housing, to press against an inner wall of the cavity and thus to fasten the sensor housing in the cavity
Implementation Method 2
The expandable hub has a conical inside that runs symmetrically to the longitudinal axis of the sensor housing. Correspondingly, the expansion element has a conical outside that runs symmetrically to a longitudinal axis of the expansion element
Data Source
Figure 1~2
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Figure 5~7
AI summary
The present invention relates to a press (10) having: a drivetrain (20) which comprises a moveable press punch (16) for transferring a pressing force onto a workpiece to be machined; and a sensor (22) for measuring the pressing force, wherein the sensor (22) is situated in a sensor housing (24) which can be releasably fastened in a cavity (26) located in the drivetrain (20), wherein the sensor housing (24) comprises a spreadable hub (30) and a spreading element (32), which is designed, when there is a relative movement of the hub (30) and the spreading element (32) along a longitudinal axis (46) of the sensor housing (24), to spread the hub (30), to press the hub against an inner wall (28) of the cavity (26) and thus to fasten the sensor housing (24) in the cavity (26).