Two-Stage Stroke Transmitter for High-Stroke Fast Actuation
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Solution Overview
Problem
Existing piezo-hydraulic actuator devices face limitations in achieving high mechanical stroke, speed, and energy efficiency simultaneously, particularly in applications requiring several millimeters to centimeters of stroke with fast trigger times and high force transmission.
Innovation Solution
A stroke transmitter comprising a hydraulic transmission unit and a cable system connected in series, allowing for a multiplicative transmission ratio that enhances the mechanical stroke and dynamics, while maintaining energy efficiency, with the hydraulic unit providing high rigidity and the cable system offering low mass and high rigidity, enabling flexible adjustment of parameters based on application requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a single-stage hydraulic transmission unit is used, then the mechanical stroke is increased compared to piezo actuators alone, but the stroke is still insufficient for applications requiring several millimeters to centimeters
Solution Approach 1:
The transmission system is divided into two independent stages: a hydraulic transmission unit (first stage) and a cable system with pulleys (second stage). Each stage can be independently optimized and adjusted, allowing the overall stroke to be tuned for different applications by modifying either stage without redesigning the entire system.
Solution Approach 2:
The patent combines two different transmission mechanisms (hydraulic and mechanical cable system) into a single integrated stroke transmitter. The hydraulic unit provides high rigidity and force, while the cable system adds stroke multiplication and flexibility, creating a hybrid system that overcomes the limitations of either mechanism alone.
2Length of moving object
If the transmission ratio is increased to achieve larger stroke, then the stroke is improved, but the force transmission capability deteriorates
Solution Approach 1:
The force transmission path is segmented into two stages with different mechanical advantages. The hydraulic stage handles high-force, low-stroke conversion, while the cable stage provides additional stroke multiplication with lower force requirements, allowing the system to achieve large overall stroke while maintaining sufficient force at each stage.
Solution Approach 2:
The system allows independent adjustment of transmission ratios in both stages. By optimizing the hydraulic cylinder area ratio and the cable pulley configuration separately, the system can achieve the desired balance between stroke and force for specific applications.
3Length of moving object
If a hydraulic transmission unit is used to increase stroke, then the mechanical stroke is improved, but the dynamics and trigger time deteriorate
Solution Approach 1:
The two-stage transmission allows the hydraulic stage to operate at high speed for rapid response, while the cable stage provides stroke multiplication. The lightweight cable system has minimal inertia, allowing fast acceleration and deceleration, thereby improving overall system dynamics despite the stroke multiplication.
Solution Approach 2:
The system enables independent optimization of dynamic parameters. The hydraulic stage can be designed for high-speed response with small displacements, while the cable stage parameters (cable mass, pulley size) can be adjusted to minimize inertia and maximize acceleration, achieving both large stroke and fast trigger time.
4Speed
If the mass of the transmission system is reduced to improve dynamics, then the speed is improved, but the rigidity and force transmission deteriorate
Solution Approach 1:
The system applies different quality characteristics to different stages: the hydraulic stage provides high rigidity and force capacity where needed, while the cable stage uses lightweight components for stroke multiplication where lower rigidity is acceptable. This localized optimization allows the system to achieve both high dynamics and sufficient rigidity.
Solution Approach 2:
The transmission system combines two different mechanical systems (hydraulic and mechanical cable) with complementary properties. The hydraulic system contributes rigidity and force, while the cable system contributes low mass and high speed capability, creating a composite transmission system that leverages the strengths of both approaches.
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 two-stage combination of hydraulic and cable systems achieves a significantly larger stroke with high dynamics and energy efficiency, overcoming the limitations of single-stage hydraulic units and pure cable systems by allowing for adjustable parameters such as stroke, force, and energy efficiency, suitable for applications like robotics and fluid injection systems.
Implementation Method 1
a first transmission unit (101, 101') configured as a hydraulic transmission unit (H, H')
Implementation Method 2
a second transmission unit (102, 102') configured as a cable system (M, M')
Data Source
AI summary
The invention relates to a stroke transmitter for an actuator device. The stroke transmitter comprises a first and a second conversion unit, which are mechanically connected to one another in series, wherein the first conversion unit is designed as a hydraulic conversion unit, it can be connected to an actuator on its drive side and it is connected to the drive side of the second conversion unit on its output side, wherein the second conversion unit is designed as a cable system and has an output element on its output side. The invention also relates to an actuator device comprising an actuator and a stroke transmitter mechanically connected in series with the actuator.