Screw Motion Mechanism With Spherical Joint Torque Limiting
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Solution Overview
Problem
The existing damping apparatus using a screw motion mechanism faces challenges in adjusting the fixing positions of clevises during installation and is prone to damage from excessive torque during unexpected vibrations.
Innovation Solution
A screw motion mechanism with a spherical joint that allows axial end connection of the threaded shaft to a structural body while preventing rotation, thereby limiting excessive torque applied to the nut member and threaded shaft, using a sliding torque mechanism that depends on axial force to control rotational torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a clevis is used to connect the threaded shaft to the structural body, then the housing member or rod member can pivot about the support shaft, but the fixing positions of the clevises require time-consuming adjustment during installation
Solution Approach 1:
The invention extracts the adjustment function from the connection mechanism by providing pre-adjustable connection holes at multiple positions on the clevis, allowing installation personnel to select and fix the optimal position directly during installation without time-consuming adjustments
Solution Approach 2:
The connection holes are pre-positioned at multiple locations on the clevis before installation, enabling the operator to simply select the appropriate hole for the desired pivot position rather than adjusting the connection after installation
2Productivity
If the threaded shaft is directly connected to the structural body, then the screw motion mechanism can convert translational motion to rotational motion, but excessive torque during unexpected vibrations can damage the nut member and threaded shaft
Solution Approach 1:
The spherical joint is designed with a predetermined sliding torque characteristic that acts as a protective mechanism before excessive torque can damage the screw motion components. The spherical portion slides within the sphere receiving portion at a controlled torque level, preventing transmission of harmful shock loads to the threaded shaft and nut member
Solution Approach 2:
The spherical joint serves as an intermediary element between the threaded shaft and the structural body. This intermediate component absorbs and dissipates excessive torque through the sliding mechanism, protecting the critical screw motion components from damage while still allowing motion conversion to occur
3Adaptability or versatility
If the spherical joint allows rotation of the threaded shaft, then the damping apparatus can accommodate postural changes, but the threaded shaft cannot be securely fixed to prevent unwanted rotation
Solution Approach 1:
The spherical joint provides dynamic adaptability by allowing the threaded shaft to pivot and adjust to different postures through the sliding of the spherical portion within the sphere receiving portion. The joint transitions from a locked state during normal operation to a movable state when postural adjustment is needed, balancing stability and adaptability
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
Facilitates easy connection of the threaded shaft to structural bodies, reduces damage by limiting excessive rotational torque, and effectively converts translational motions into rotational motions without causing harm to the screw motion components.
Implementation Method 1
a sliding torque which is a torque required for rotating the spherical portion (33) of the spherical joint relative to the sphere receiving portion (36) of the spherical joint, whereas the sliding torque is dependent on an axial force applied to the threaded shaft (30)
Implementation Method 2
a threaded shaft (30) having an outer peripheral surface provided with a helical thread groove
Implementation Method 3
when the rotor is rotated, a shear friction force in proportion to a rotational angular speed of the rotor is applied to the viscous fluid in the containing chamber. As a result, heat is generated in the viscous fluid
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Provided is a screw motion mechanism capable of facilitating connection of an axial end of a threaded shaft with respect to a structural body while preventing a rotation of the threaded shaft, and capable of preventing application of an excessive torque to a nut member and the threaded shaft and preventing damage on those members. The screw motion mechanism includes: a threaded shaft (30) having an outer peripheral surface provided with a helical thread groove, the threaded shaft (30) having at least one axial end coupled to a first structural body; a nut member (40) held in a rotatable manner with respect to a second structural body which is movable in an axial direction of the threaded shaft with respect to the first structural body, the nut member (40) being threadedly engaged with the threaded shaft; and a spherical joint (32) for coupling the at least one axial end of the threaded shaft (30) to the first structural body, the spherical joint (32) including: a spherical portion (33, 61); and a sphere receiving portion (36, 60) for housing the spherical portion. When assuming an axial force applied to the threaded shaft (30) as a variable, a line of a rotational torque intersects with a line of a sliding torque in a graph, and the sliding torque exceeds the rotational torque under an initial state in which the axial force is not applied to the threaded shaft (30).