Four-Stage Telescopic Actuator Screw Drive Extension
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Solution Overview
Problem
Existing telescopic actuators face challenges in achieving a large extension path with compact dimensions while maintaining exact and targeted adjustment during extension and retraction processes.
Innovation Solution
A telescopic actuator design featuring four screw drives, where at least one is a ball screw drive with a ball screw spindle and nut, allowing for a total extension path composed of four partial paths, enabling a compact retracted state with a significantly longer extended state, up to 4 times the retracted length, and utilizing mixed screw drives for enhanced flexibility and non-dependent extraction sequence on friction conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a telescopic actuator uses a single screw drive, then the structure is simple, but the extension path is limited relative to the retracted length
Solution Approach 1:
The actuator divides the extension path into four independent partial extension paths, each handled by a separate screw drive. This segmentation allows the total extension path to be the sum of all partial paths, achieving a large extension path while keeping each individual screw drive compact and manageable.
Solution Approach 2:
The four screw drives are arranged concentrically with one another, similar to nested dolls. The first screw drive is surrounded by the second, which is surrounded by the third, and the fourth is inside the third. This nesting arrangement allows all four screw drives to occupy a compact radial space while each contributes to the total extension path.
2Length of moving object
If a telescopic actuator extends on one side only, then the structure is simpler, but the extension capability is limited
Solution Approach 1:
The actuator employs asymmetric screw drives where at least one screw drive has a different pitch than the others. Specifically, the first screw drive has a first pitch while the second screw drive has a second pitch that differs from the first. This asymmetry in pitch values allows for optimized distribution of extension paths while maintaining the bilateral extension capability.
3Measurement precision
If ball screw drives are used, then friction is reduced and positioning accuracy is improved, but the device complexity increases
Solution Approach 1:
The actuator uses different types of screw drives for different positions and load requirements. At least one of the four screw drives is designed as a ball screw drive with ball incorporation to reduce friction and improve positioning accuracy where needed. Other screw drives may use different mechanisms, allowing optimization of each location's specific requirements rather than uniformly applying the most complex solution throughout.
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 design allows for a compact retracted state with a large extension path, ensuring precise and targeted positioning at each operating stage, independent of individual screw drive friction, and includes a braking mechanism to prevent unwanted displacement.
Implementation Method 1
ball screw drive has a ball screw spindle with a circumferential thread and a ball screw nut, the ball screw nut and ball screw spindle coming into positive engagement with the incorporation of balls
Implementation Method 2
The advantage is, in particular, low friction between the ball screw nut and the ball screw spindle due to the incorporation of the balls
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a telescopic actuator (1) for carrying out a linear movement. Said telescopic actuator comprises a motor (3) which applies a drive torque to a screw drive so that a lead screw can be linearly extended or retracted with respect to a screw nut. The invention is characterized in that the telescopic actuator (1) has four screw drives (K1, K2, K3, K4) and is extended or retracted on both sides in the axial direction (A), the total amount of extension (GA) being constituted by four partial amounts of extension (GA1, GA2, GA3, GA4).