Articulated Robot Stopper Structure for Shear Load Absorption
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Solution Overview
Problem
Existing stopper structures for articulated robots, such as those disclosed in JP 2007-118114A, fail to effectively absorb shear loads and require sufficient space, making it difficult to implement at axes with large operation ranges where space is limited, and they cannot handle high impact energies generated by increased robot speeds.
Innovation Solution
A stopper structure comprising a protrusion on one arm or mechanical element, a hole in the other, and a stopper made of an elastic resin with a metal surface plate that is partially exposed, allowing it to absorb shear loads and maintain high impact-absorbing performance even in constrained spaces by using a polygonal prism block and a retaining plate to secure the stopper in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a rubber stopper made of an elastic body is used to absorb impact energy, then impact absorption capability is improved, but the stopper cannot receive shear loads due to dynamic loads and does not function as a stopper
Solution Approach 1:
The stopper combines an elastic body (urethane) with a rigid member (metal plate) to create a composite structure. The elastic body absorbs impact energy through compression, while the rigid member provides shear load resistance and structural stability, allowing the stopper to function reliably under dynamic loads
Solution Approach 2:
The invention merges the impact absorption function of the elastic body with the shear load resistance function of the rigid member into a single integrated stopper component, enabling both functions to work simultaneously in one element
2Loss of energy
If a stopper structure is designed to absorb impact energy with sufficient thickness and width, then impact absorption is improved, but it becomes difficult to ensure required space at axes with large operation ranges
Solution Approach 1:
The rigid member is strategically positioned at the front surface of the elastic body that contacts the protrusion, providing shear load resistance exactly where needed during operation, while the elastic body provides compression throughout its volume for impact absorption, optimizing space utilization
3Productivity
If robot operation speed is increased to improve productivity, then productivity is improved, but impact energy generated during arm contact increases
Solution Approach 1:
The composite structure of elastic body and rigid member provides enhanced impact energy absorption capacity proportional to the increased impact energies from high-speed operation, allowing the robot to maintain high speeds without compromising safety or requiring deceleration
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 stopper structure effectively restricts relative rotation by a predetermined angle, absorbs shear loads, and maintains high impact-absorbing performance, enabling high-speed operation without deceleration, even at axes with large operation ranges where space is limited, by utilizing the elastic deformation of the resin block and metal surface plate.
Implementation Method 1
a block made of an elastic resin
Implementation Method 2
a metal surface plate that has a bent cross-section, and is provided on a surface of the block along a front side on which the stopper comes into contact with the protrusion
Data Source
AI summary
It is an object of the present invention to provide a stopper structure that can be arranged even at a position where no sufficient space can be ensured, such as at an axis at which an arm has a large operation range, and can appropriately absorb a shear load, and an articulated robot including such a stopper structure. A stopper structure according to the present invention relates to a stopper structure 100a for restricting relative rotation between an arm 120 and a mechanical element (base 110) by a predetermined angle or more, the stopper structure including: a protrusion 122 provided on one of the arm and the mechanical element; a hole 116 formed in the other one of the arm and the mechanical element; and a stopper 140 inserted into the hole while being partially exposed from the hole, wherein the stopper including: a block 150 made of an elastic resin; and a metal surface plate 160 that has a bent cross-section, and is provided on a surface of the block along a front side on which the stopper comes into contact with the protrusion.