Linear Actuator Downsizing via Axial Electromagnetic Resonance
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Solution Overview
Problem
Existing linear actuators for electric brushes, cutting machines, and air pumps face challenges in downsizing, assemblability, and cost reduction due to complex mechanisms and high component counts, particularly when mounted in cylindrical equipment.
Innovation Solution
A linear actuator design featuring an electromagnet with a unipolar magnetized coil, a movable member with an output shaft, and an elastic body for reciprocation support, where the magnet and electromagnet are aligned along the coil-winding axis, and an alternating-current supply is used to resonate the movable member for efficient linear motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a motion direction conversion mechanism is used to convert axial rotation into linear reciprocation, then the actuator can drive movable parts, but the device size increases and cannot be easily downsized
Solution Approach 1:
The patent replaces the conventional motion direction conversion mechanism with a direct linear reciprocating structure. The coil and magnet are arranged to generate electromagnetic force that directly drives linear reciprocation without requiring mechanical conversion components, thereby eliminating the need for complex mechanisms and reducing overall actuator size.
Solution Approach 2:
The actuator is divided into distinct functional segments: a fixing body for mounting, a movable body containing the coil and magnet, and a shaft for output. This segmentation allows each component to be optimized independently and facilitates easy assembly and disassembly while maintaining compact overall dimensions.
2Ease of operation
If a motion conversion mechanism is used, then linear reciprocation can be achieved, but noise increases and power loss occurs reducing efficiency
Solution Approach 1:
The patent eliminates mechanical friction and conversion losses by using direct electromagnetic force generation. The coil and magnet interact to produce linear motion without mechanical intermediaries, significantly reducing energy loss and improving overall efficiency.
Solution Approach 2:
The actuator utilizes controlled vibration and reciprocation at resonant frequencies to achieve efficient linear motion. By operating at optimal vibration characteristics, the system minimizes energy dissipation while maintaining effective driving force.
3Adaptability or versatility
If multiple magnets are used as in PTL 2, then the actuator can be mounted in cylindrical equipment, but the number of components increases making assembly difficult and cost high
Solution Approach 1:
The patent combines the coil and magnet into a single integrated movable body unit. This merging of components reduces the total part count, simplifies assembly procedures, and lowers manufacturing costs while maintaining the ability to mount in cylindrical equipment through the overall actuator design.
Solution Approach 2:
The movable body serves multiple functions simultaneously: it contains the electromagnetic components, provides structural support, enables linear reciprocation, and facilitates mounting in various configurations including cylindrical equipment. This multi-functionality reduces the need for separate dedicated components.
4Ease of operation
If the movable member reciprocates in lateral direction as in PTL 1, then linear motion is achieved, but lateral space is required making downsizing difficult
Solution Approach 1:
Instead of having the movable member reciprocate laterally as in conventional designs, the patent inverts the arrangement so that the coil and magnet are positioned to generate force along the axial direction. This inversion allows linear reciprocation to occur in the axial direction, eliminating the need for lateral clearance and enabling compact design.
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 configuration enables downsizing, improves assemblability, and reduces costs while providing stable linear reciprocation with enhanced energy efficiency and reliability.
Implementation Method 1
an electromagnet including a coil; a magnet disposed to face the coil in a coil-winding axis direction of the coil
Implementation Method 2
the coil is electrified to excite the plunger such that the plunger functions as an electromagnet
Implementation Method 3
an elastic body disposed along the coil-winding axis direction and configured to elastically deform in the coil-winding axis direction to support the movable member
Implementation Method 4
an alternating-current supplying section configured to supply an alternating current having a frequency substantially equal to a resonance frequency of the movable member to the coil
Data Source
AI summary
A linear actuator that can achieve downsizing with a simple configuration, and can provide stable linear reciprocation while achieving improvement in assemblability and cost reduction. In the actuator, movable member 50 faces coil 21 in the winding axis CL direction of coil 21, and in addition, includes magnet 30 magnetized in the coil-winding axis CL direction in a unipolar fashion and output shaft 60 extending in the CL direction. Elastic body 70 is disposed along the coil-winding axis CL direction and configured to deform in that direction to supports movable member 50 such that movable member 50 can reciprocate along the coil-winding axis CL direction. Elastic body 70 is fixed to fixing body 40 and movable member 50 at both ends 71 and 72 in the coil-winding axis CL direction such that central air gap CG is formed between electromagnet 20 and magnet 30.