Dual-Chamber Actuator with Passive Fluid Paths for Four-Quadrant Motion
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Solution Overview
Problem
Existing actuator devices lack a simple and cost-effective mechanism for achieving four-quadrant operation, which allows for controlled movement and braking of an output element in both compressive and tensile directions without requiring active components.
Innovation Solution
An actuator device with two coupled working chambers, each connected to a separate flow path, utilizing a solid-state actuator and check valves to manage fluid flow, enabling four-quadrant operation through volume changes in the chambers without active components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear actuator is constructed with a piston, piston chamber, and seal arrangement, then it can achieve linear movement through pressure differential, but the seal subject to reciprocating frictional wear has limited service life
Solution Approach 1:
The patent replaces the mechanical seal system with a magnetic coupling system. The drive shaft is magnetically coupled to the piston through magnetic attraction and repulsion forces, eliminating the need for physical contact between moving parts. This substitution of mechanical coupling with magnetic coupling eliminates reciprocating frictional wear at the seal interface while maintaining effective force transmission for linear actuator operation.
2Ease of manufacture
If conventional linear actuators are used in implantable medical devices, then they can provide mechanical actuation, but they present biocompatibility concerns and are difficult to implant
Solution Approach 1:
The patent replaces conventional mechanical actuation systems with a magnetic actuation system. The drive shaft generates magnetic fields that couple with the piston, enabling contactless force transmission. This eliminates the need for penetrating seals and mechanical interfaces that would compromise biocompatibility, making the device suitable for implantable medical applications such as injecting therapeutic agents through the skin.
Solution Approach 2:
The magnetic drive shaft serves multiple functions: it generates the magnetic field for contactless actuation, transmits rotational motion to linear piston movement through magnetic coupling, and enables precise control of the piston's reciprocating motion. This multi-functionality reduces the number of separate components needed, simplifying the overall device structure for implantation.
3Reliability
If a seal arrangement is used to prevent fluid communication between piston chamber and rod chamber, then fluid containment is achieved, but the seal experiences reciprocating frictional wear
Solution Approach 1:
The patent eliminates the mechanical seal arrangement by using magnetic coupling between the drive shaft and piston. The magnetic field penetrates the chamber walls to transmit force without physical contact, maintaining fluid containment between the piston chamber and rod chamber while eliminating the reciprocating frictional wear that would occur with traditional seals.
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
Enables controlled movement and braking of the output element in both compressive and tensile directions with reduced parts, weight, and cost, while maintaining efficient fluid management.
Implementation Method 1
the drive shaft (152) includes a first permanent magnet (154) and a second permanent magnet (156), and the piston (158) includes a third permanent magnet (160). The actuator device utilizes magnetic fields generated by the magnets to transfer rotational motion of the drive shaft to linear motion of the piston.
Implementation Method 2
the piston (158) includes a flexible membrane (162) that transduces a pressure differential into linear motion of the piston.
Data Source
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AI summary
The invention relates to an actuator device (10), having two working chambers (12, 14) which are coupled to one another in such a way that a volume increase in a first of the working chambers (12, 14) is associated with a volume decrease in the second working chamber (14), and vice versa. There is provided an output device (18) which can be driven, and thus moved, by the respective volume increase in the respective working chamber (12, 14). There is provided a pump device (36) having a solid-state actuator (38) and intended for conveying a fluid. There is provided a first flow path (42) through which the fluid conveyed by means of the pump device (36) can flow and via which, to bring about the volume increase in the first working chamber (12), the fluid conveyed by means of the pump device (36) and flowing through the first flow path (42) can be introduced into the first working chamber (12).