Linear Motor Brake Pad Positioning Without Backlash
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Solution Overview
Problem
Existing brake apparatuses for linear motors face challenges in achieving precise positioning and avoiding positional deviations due to backlash and lack of rigidity, which hinder accurate positioning to within 1 μm accuracy.
Innovation Solution
The brake apparatus employs a guide rail and slide table system with rolling balls and a plate spring mechanism, where the brake pad is fixed to the plate spring's end, allowing for precise positioning and retention using a combination of resilient and electromagnetic forces, minimizing backlash and positional deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a brake pad and fixing member arrangement is used for positioning, then the movable section can be positioned at a predetermined position, but backlash between the brake pad and fixing member prevents positioning accuracy of not more than 1 μm
Solution Approach 1:
The patent replaces the conventional mechanical brake pad pressing system with an electromagnetic positioning system. Electromagnets are used to attract the movable section to the fixed section, eliminating the need for physical contact between brake pads and fixing members. This substitution of mechanical contact with electromagnetic force eliminates backlash entirely while achieving the required positioning accuracy of not more than 1 μm.
2Ease of operation
If a plate spring is used to support the electromagnet, then the electromagnet can be positioned, but the plate spring is not rigidly secured causing positional deviation of the movable section
Solution Approach 1:
The patent applies preliminary action by pre-tensioning the plate spring during assembly. The plate spring is configured with a specific curvature and tension before the electromagnet is activated, ensuring that the electromagnet is held in the correct initial position. This preliminary mechanical positioning, combined with the electromagnetic force, prevents positional deviation of the movable section while maintaining ease of electromagnet positioning.
3Device complexity
If the brake pad is not rigidly secured, then the structure is simpler, but the movable section undergoes positional deviation due to deformations of the brake pad after positioning
Solution Approach 1:
The patent eliminates the brake pad deformation problem by replacing the mechanical pressing system with an electromagnetic attraction system. The electromagnet creates a magnetic field that attracts the movable section to the fixed section without requiring physical contact or mechanical pressing. This eliminates brake pad deformation entirely while maintaining structural simplicity, as the electromagnetic system requires no rigid fixation of flexible components.
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 solution enables accurate and reliable positioning of the movable section with respect to the fixed section, reducing heat generation and electromagnetic noise, while improving durability by utilizing the resilient force of the plate spring for retention, thus enhancing positioning accuracy and reducing operational heat and vibrations.
Implementation Method 1
a coil arranged on any one of a movable section and a fixed section thereof, and as necessary, a permanent magnet is arranged on the other of the movable section and the fixed section, so that the permanent magnet is opposed to the coil. The movable section is displaced with respect to the fixed section by means of a thrusting force, which is generated on the basis of Fleming's left hand rule when a current flows through the coil.
Implementation Method 2
a thrusting force, which is generated on the basis of Fleming's left hand rule when a current flows through the coil
Implementation Method 3
when electric power applied to the electromagnet is halted, the brake pad presses the brake base by an urging force of a coil spring, which is arranged between the electromagnet and the brake pad
Data Source
AI summary
When respective magnetic fluxes are generated by coils and pass through a plate spring, an electromagnetic force, which results from the magnetic flux, is generated within a plate spring, screws, and a magnetic flux-passing member. Therefore, a brake pad is separated from a slide table in accordance with an action of the electromagnetic force exerted against a resilient force of the plate spring. On the other hand, when generation of respective magnetic fluxes from the coils is halted, the electromagnetic force is extinguished, and thus the brake pad presses against the slide table, in accordance with an action of the resilient force of the plate spring.