Linear drive apparatus for converting a rotational movement into a linear movement and medical technology apparatus
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Solution Overview
Problem
Planetary roller screw-thread drives for converting rotational to linear movement are expensive to manufacture.
Innovation Solution
A linear drive apparatus with an outer casing and inner casing supported via main and radial bearings, allowing the spindle and ring to rotate eccentrically, utilizing trapezoidal threads for minimal friction and direct drive, and optionally incorporating a securing element to prevent slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a planetary roller screw-thread drive is used to convert rotational movement into linear movement, then the advantages of minimal wear and direct drive capability are achieved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent uses a simplified geometric model that copies only the essential functional elements of the planetary roller screw-thread drive (the threaded spindle and planetary rollers) while eliminating complex manufacturing features. This allows achieving the core functionality with standard machining operations, significantly reducing manufacturing cost while maintaining the wear-resistant rolling contact mechanism
Solution Approach 2:
The patent extracts and isolates the critical wear-reduction mechanism (rolling contact between threaded surfaces) from the complex planetary roller screw-thread drive architecture. By taking out only the essential threaded spindle and planetary roller components and eliminating unnecessary structural elements, the design achieves minimal wear through rolling movement while simplifying manufacturing processes
2Reliability
If a recirculating ball screw is used to convert rotational movement into linear movement, then the mechanism is well-established and reliable, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the essential motion conversion function from the complex recirculating ball screw mechanism by retaining only the threaded spindle and planetary rollers that provide rolling contact. This eliminates the need for ball recirculation pathways, guide blocks, and other complex components, reducing manufacturing complexity while maintaining reliable rotational-to-linear motion conversion
Solution Approach 2:
The patent creates a simplified geometric model that copies only the fundamental functional elements needed for reliable operation (threaded surfaces with rolling contact) while omitting the complex recirculating ball screw architecture. This approach maintains mechanism reliability through proven threaded engagement while dramatically reducing manufacturing complexity
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
Realizes the advantages of planetary roller screw-thread drives with reduced manufacturing costs, minimal friction, and precise control of linear movement, suitable for medical technology apparatus and other applications.
Implementation Method 1
an inner casing (8) which is supported in the outer casing (3) via at least one main bearing (10) in such a way that the inner casing (8) is able to rotate about a main axis (11)
Implementation Method 2
a ring (9) which is supported in the inner casing (8) via at least one radial bearing (12) in such a way that the ring (9) is able to rotate about a ring axis (13)
Implementation Method 3
an inner contour (14) is provided on an inner surface of the ring (9) and an outer contour (15) is provided on an outer surface of the spindle (4), said outer contour (15) and said inner contour (14) engaging locally with one another along a circumferential direction (16) extending around the main axis (11)
Implementation Method 4
utilizing trapezoidal threads for minimal friction
Implementation Method 5
the main axis (11) and the ring axis (13) are arranged relative to one another in such a way that the inner casing (8) and the ring (9) are supported in a reciprocally eccentric manner, said outer contour (15) and said inner contour (14) engaging locally with one another
Data Source
AI summary
One or more example embodiments relates to a linear drive apparatus for converting a rotational movement into a linear movement.