Slide Actuator Retainer Spring Design for Position Control
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Solution Overview
Problem
Conventional slide actuators experience positional deviation and friction issues due to external disturbances, leading to premature contact of the retainer with the fixed member's wall, resulting in reduced position control accuracy and increased frictional resistance.
Innovation Solution
A slide actuator design incorporating a mechanical retainer spring with a specific spring constant range that induces sliding friction to prevent retainer contact with the wall, coupled with a control system to correct deviations and maintain precise position control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the retainer is allowed to move freely to accommodate external disturbances, then the reliability is improved, but the positional deviation increases and position control accuracy deteriorates
Solution Approach 1:
A retainer spring is introduced to provide beforehand cushioning for the retainer. The spring absorbs external disturbances and prevents the retainer from contacting the grease reservoir, thereby maintaining position control accuracy while accommodating disturbances. The spring constant is specifically designed to balance between absorbing shocks and preventing excessive displacement.
2Measurement precision
If the spring constant is increased to suppress retainer displacement, then the position control accuracy is improved, but the sliding friction in the balls increases
Solution Approach 1:
The spring constant of the retainer spring is optimized to a specific range (10 N/m to 100 N/m) to balance two opposing requirements: suppressing retainer displacement to maintain position control accuracy, and allowing sufficient movement to prevent sliding friction in the balls. This parameter optimization resolves the contradiction between precision and friction.
3Measurement precision
If the retainer contacts the wall portion to correct deviation, then the position control is improved, but the harmful factors increase due to grease reservoir formation
Solution Approach 1:
The retainer spring provides beforehand cushioning that prevents the retainer from contacting the grease reservoir in the first place. By absorbing external disturbances and maintaining the retainer within the predetermined stroke range, the spring eliminates the harmful contact with the grease reservoir while still enabling position control through controlled movement.
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 solution effectively minimizes positional deviation and enhances position control accuracy by preventing retainer contact with the grease reservoir, reducing sliding friction and maintaining high precision even under external disturbances.
Implementation Method 1
a structure having spring properties configured to couple the wall portion and the retainer. The structure is disposed to suppress displacement of the retainer in the moving direction
Implementation Method 2
a plurality of balls interposed between the fixed member and the movable member and configured to movably support the movable member
Data Source
AI summary
A slide actuator includes a fixed member, a movable member capable of reciprocating in a predetermined direction with respect to the fixed member, a plurality of balls interposed between the fixed member and the movable member and configured to movably support the movable member, a retainer interposed between the respective balls and configured to keep an interval between the respective balls constant and reciprocate in a predetermined stroke range, a wall portion of the fixed member provided in a moving direction of the retainer, and a retainer spring configured to couple the wall portion and the retainer. The retainer spring is disposed to suppress displacement of the retainer in the moving direction. A spring constant of the retainer spring is set to a value for causing sliding friction in the balls and pushing back the retainer in a range in which the retainer moves beyond the predetermined stroke range.