Cycloidal Drive Assembly for Compact High-Torque Drug Delivery
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Solution Overview
Problem
Existing drug delivery devices face challenges in achieving a compact design with high gear ratio and high torque transmission, while also being cost-effective and easy to assemble.
Innovation Solution
The integration of a cycloidal drive with a planetary drive mechanism, which includes a drive shaft, pinion, cycloidal disc, and stationary ring gear, allows for increased gear ratio without increasing size, and uses a minimal number of parts for efficient torque transmission, including the option of using a stepper motor for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a cycloidal drive is used to achieve high gear ratio in compact size, then the gear ratio is increased without increasing size, but the torque transmission capability is reduced
Solution Approach 1:
The patent combines a cycloidal drive and a planetary drive into a single integrated gear arrangement. The cycloidal drive provides compact size and high gear ratio, while the planetary drive contributes high torque transmission capability. The two drive mechanisms are merged such that they work together in a unified structure, allowing the system to simultaneously achieve both small dimensions and high torque transmission.
2Volume of moving object
If the gear arrangement is made compact to reduce device size, then the overall size is reduced, but the torque transmission capability deteriorates
Solution Approach 1:
The patent merges cycloidal drive and planetary drive mechanisms into a compact integrated gear arrangement that maintains high torque transmission capability while reducing overall device size.
Solution Approach 2:
The planetary drive is nested within the cycloidal drive structure, with planetary gears positioned inside the cycloidal mechanism. This nesting arrangement allows both drive mechanisms to occupy the same spatial envelope, achieving compact overall dimensions while maintaining the torque transmission advantages of the planetary drive.
3Ease of manufacture
If a manual drive mechanism is used to reduce complexity, then the device is easier to manufacture, but the precision of dose delivery is reduced
Solution Approach 1:
The patent replaces the manual drive mechanism with an electric motor-driven system. The electric motor provides precise control over the dosing process, enabling accurate and consistent dose delivery. The motor can be controlled to deliver exact amounts of medication, improving measurement precision compared to manual operation.
Solution Approach 2:
The patent incorporates feedback mechanisms including a dose setting mechanism with a display that shows the selected dose to the user, and sensors that monitor the actual dose delivered. This feedback allows for verification of the dosing process and ensures precise dose delivery by comparing the intended dose with the actual delivered dose.
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 a compact, high-torque transmission system that is cost-effective and easy to manufacture, suitable for small drug delivery devices, with the ability to precisely control the delivery of medicaments.
Implementation Method 1
The cycloidal disc is driven in an eccentric motion by means of a planet gear which meshes with the pinion on the drive shaft and with an internal gear of the cycloidal disc
Implementation Method 2
The cycloidal disc is driven in an eccentric motion by means of a planet gear which meshes with the pinion on the drive shaft
Data Source
AI summary
A drive for a drug delivery device includes a drive mechanism with a drive shaft, a pinion arranged on the drive shaft and a cycloidal drive. The cycloidal drive has a cycloidal disc and a ring gear. The cycloidal disc is driven in an eccentric motion by means of a planet gear, which meshes with the pinion on the drive shaft and with an internal gear of the cycloidal disc. Further, the present application also relates to a drug delivery device with the aforementioned drive.