Radial Locking Body Shaft Lock for High-Torque Low-Play Holding
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Solution Overview
Problem
Existing shaft locks lack a structurally simple, spatially compact design that efficiently transmits high mechanical moments with minimal rotational play, while also being cost-effective and tolerant of misalignments.
Innovation Solution
A shaft lock with a radially inner rotor part and a fixed radially outer stator part, utilizing locking bodies that can be engaged and disengaged via an actuator to create a positive connection, allowing for high torque transmission with minimal installation space and no energy requirement in the holding or locking states, and featuring a compact, robust, and cost-effective construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shaft locking device uses additional hydraulic locking cylinders or extendable threaded rods to block rotation, then the locking function is achieved, but the structural complexity and installation space increase
Solution Approach 1:
The locking device is segmented into discrete locking bodies (balls, cylinders, or rollers) that can be individually actuated and positioned within the stator part. Each locking body operates independently within its own receiving pocket, allowing the system to achieve reliable locking through multiple simple, modular elements rather than a single complex mechanism.
Solution Approach 2:
The locking bodies are actuated and positioned in the radial dimension, moving between a retracted position (unlocked) and an engaged position (locked) within radially oriented receiving pockets. This radial actuation dimension enables compact locking without requiring axial extension or rotational complexity.
2Force
If conventional locking mechanisms use extendable components to achieve locking, then the locking force is sufficient, but the installation space and device volume increase
Solution Approach 1:
The locking bodies are nested within receiving pockets that are formed as cavities in the stator part. When locked, the locking bodies are contained within these pre-formed recesses, eliminating the need for external extension mechanisms. The entire locking mechanism fits within the radial thickness of the stator part, achieving high locking force in a compact volume.
Solution Approach 2:
The locking force is generated through radial positioning of the locking bodies within the stator part thickness, rather than requiring axial extension. This utilizes the radial dimension for force transmission, enabling compact axial and radial footprints while maintaining sufficient locking force through the form-fitting engagement in receiving pockets.
3Reliability
If friction-locking or force-locking mechanisms are used to block rotation, then the locking function is achieved, but energy is continuously required to maintain the locked state
Solution Approach 1:
The locking mechanism is self-holding through the form-fitting engagement of the locking bodies in the receiving pockets. Once actuated into the locked position, the geometric interference fit maintains the locked state without requiring continuous energy input. The system serves itself by using the mechanical geometry of the locking bodies and receiving pockets to maintain the locked state passively.
Solution Approach 2:
The continuous energy requirement for friction-locking mechanisms is extracted and eliminated by replacing it with a positive-locking mechanism. The locking function is achieved through discrete geometric engagement rather than continuous frictional force, removing the need for sustained energy consumption to maintain the locked state.
4Reliability
If mechanical locking devices with multiple components are used, then the locking function is reliable, but manufacturing cost and assembly complexity increase
Solution Approach 1:
The stator part serves multiple functions: it provides the structural housing, contains the receiving pockets for locking bodies, provides the radially continuous openings for actuation, and defines the geometric engagement surfaces. This multi-functionality reduces the total component count and simplifies manufacturing compared to devices with separate housings, mounting brackets, and locking mechanisms.
Solution Approach 2:
The locking mechanism uses standardized, interchangeable locking bodies (balls, cylinders, or rollers) that can be manufactured independently and assembled into the stator part. This segmentation allows for simplified manufacturing of individual components using standard machining or forming processes, and enables easy replacement or maintenance without affecting the entire assembly.
Data Source
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AI summary
The invention relates to a shaft lock (10), comprising a radially inner rotor part (12), which is centrally connected to a shaft (16) having an axis of rotation (14). A stationary, radially outer stator part (20) extends at least partly around the shaft (16) and the radially inner rotor part (12) coaxially. According to the invention, in a locked state and in a holding state, an interlocking connection (30) can be established by means of a plurality of locking bodies (40) between the radially inner rotor part (12) and the stationary, radially outer stator part (20), and the interlocking connection (30) can be released for the transition into an unlocked state. Thus, the shaft lock (10) has a simple and compact design. The shaft lock (10) can be produced by using mostly standard machine components and allows high torques to be transmitted with almost no rotational play. The holding state and the locked state are permanently maintained without energy being supplied, as is the unlocked state. Energy has to be supplied only for switching between the three states.