Linear Actuator Coupling for Spindle Misalignment Insulation
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Solution Overview
Problem
Linear actuators face challenges in reducing built-in dimensions, providing thermal and electrical insulation, compensating for misalignment between the output end of the transmission and the spindle, and being retrofittable for various applications in hospital and care sectors.
Innovation Solution
A linear actuator design incorporating a coupling system with a first and second coupling part and an intermediate coupling member, which allows for radial misalignment compensation, reduces built-in dimensions by integrating the motor with the transmission housing, and uses recesses in the coupling member for thermal and electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a coupling with intermediate coupling member is used to compensate for misalignment between transmission and spindle, then misalignment compensation is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediate coupling member as a mediator between the first coupling part (connected to transmission) and the second coupling part (connected to spindle). This intermediate member enables misalignment compensation by providing a sliding connection that can accommodate radial deviations while transmitting torque, thus resolving the misalignment issue without requiring complex adjustment mechanisms.
Solution Approach 2:
The coupling is divided into three distinct segments: a first coupling part, an intermediate coupling member, and a second coupling part. This segmentation allows each component to perform its specific function - the first and second parts provide connection interfaces while the intermediate part provides the misalignment compensation through sliding movement, simplifying the overall design compared to a monolithic coupling.
2Volume of moving object
If the motor is integrated with the transmission housing to reduce built-in dimensions, then compactness is improved, but thermal insulation requirements increase
Solution Approach 1:
The patent extracts the thermal and electrical insulation function from the overall motor-transmission assembly by introducing a specific insulation arrangement between the motor and the spindle. This allows the motor to be integrated with the transmission housing for compactness while separately addressing the heat transfer issue through dedicated insulation components, preventing harmful thermal effects on the spindle.
3Manufacturing precision
If a three-component coupling is used instead of direct connection, then misalignment compensation is improved, but torque transmission efficiency may be reduced
Solution Approach 1:
The intermediate coupling member is designed with sliding connections that dynamically adapt to misalignment conditions. The sliding surfaces maintain continuous contact while accommodating radial deviations, ensuring smooth torque transmission without the energy losses associated with rigid connections that would require precise alignment or flexible connections that would introduce friction and hysteresis.
Data Source
AI summary
A linear actuator (1) comprising an electric motor (20), a transmission (40), a spindle (80) being connected to the transmission (40), a spindle nut (81) being arranged on the spindle (80), a housing (10), an outer tube (3) being connected to the housing (10), and an inner tube (2) being connected to the spindle nut (81). The spindle nut (81) and the inner tube (2) are guided inside the outer tube (3). The transmission (40) including a transmission housing (41), a transmission input end and a transmission output end positioned opposite the transmission input end. A coupling (30) including a first coupling part (32) being connected to the output end of the transmission, a second coupling part (34) being connected to the end of the spindle and a coupling member (36) disposed between the first and second coupling parts (32, 34) and slidably engaged with the first and second coupling parts (32, 34).