Separate Locking Pin and Plunger in Electric Linear Actuator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing electric linear motion actuators face issues with mechanical strength and reliability due to the integration of the locking pin with the plunger, leading to potential damage and reduced magnetic attraction force, as well as compromised durability and sliding properties caused by grease interference.
Innovation Solution
The electric linear motion actuator features a separate locking pin made of non-magnetic material, a return spring for elastic force, and a guiding mechanism with pin holes to disperse moment loads, preventing magnetic leakage and enhancing durability by separating the plunger and locking pin and using a spring housing space to isolate grease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the locking pin is made of low carbon steel to form a magnetic circuit, then the magnetic attraction force is improved, but the mechanical strength of the locking pin becomes insufficient
Solution Approach 1:
The locking mechanism is divided into two separate components: a plunger made of low carbon steel that forms the magnetic circuit, and a locking pin made of non-magnetic material with high mechanical strength. This segmentation allows each component to be optimized for its specific function without compromise.
Solution Approach 2:
The plunger acts as an intermediary component between the coil and the locking pin. It transmits the magnetic attraction force generated by the coil to the locking pin, enabling the locking pin to be made of non-magnetic material while still achieving reliable locking through the plunger's magnetic coupling.
2Device complexity
If the locking pin is formed integrally with the plunger, then the structure is simplified, but the magnetic attraction force is reduced due to magnetic leakage to the locking pin
Solution Approach 1:
The locking pin and plunger are separated into distinct components. The plunger is exclusively responsible for forming the magnetic circuit with the coil, while the locking pin serves as a separate mechanical locking element. This prevents magnetic leakage to the locking pin and maintains strong magnetic attraction force.
3Reliability
If the locking pin is engaged with the locking portion, then the braking force is maintained without motor energization, but the moment load may damage the locking pin due to insufficient mechanical strength
Solution Approach 1:
The locking pin is separated from the plunger and made of non-magnetic material with high mechanical strength, allowing it to withstand the moment load during locking without being compromised by magnetic circuit requirements.
Solution Approach 2:
The plunger serves as a mediator that transmits force from the coil to the locking pin without requiring the locking pin itself to be part of the magnetic circuit, thereby protecting the locking pin from damage while maintaining locking reliability.
4Ease of operation
If grease is present in the system for lubrication, then the sliding properties are improved, but the grease interferes with the magnetic circuit and reduces magnetic attraction force
Solution Approach 1:
The locking pin is extracted from the magnetic circuit, allowing grease to be present in the magnetic circuit area without interfering with magnetic attraction. The non-magnetic locking pin can slide through the magnetic field region without being affected by grease, while the plunger maintains strong magnetic coupling.
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 reliable locking operations with improved durability and reduced risk of damage, maintaining braking force without energizing the electric motor, while preventing unnecessary energy consumption.
Implementation Method 1
a return spring configured to apply an elastic force to the locking pin, thereby allowing the plunger to move backward along with the locking pin
Implementation Method 2
a linear solenoid configured to move the locking pin forward and backward; wherein a plunger of the linear solenoid and the locking pin are formed as separate parts
Data Source
AI summary
An electric linear motion actuator includes a locking mechanism for locking and unlocking the rotor shaft of an electric motor. The locking mechanism includes circumferentially arranged locking holes provided in a gear of a reduction gear mechanism, a locking pin moved toward and away from the locking holes, and engaged in one locking hole to lock the gear when the locking pin is moved toward the gear, and a linear solenoid for moving the locking pin toward and away from the gear. The plunger of the linear solenoid and the locking pin are formed as separate parts, and disposed coaxial with each other with their end faces axially facing each other. This prevents the moment load applied from the gear to the locking pin from acting on the plunger, thereby preventing damage to a bobbin slidably supporting the radially inner surface of the plunger.