Open Ball Screw Assembly for Holder Clearance Without Sagging
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Solution Overview
Problem
Conventional ball screw assemblies with supporting holders face issues of sagging and deflection due to the weight of the screw, leading to manufacturing precision problems and potential interference between the nut and the supporting holder, which affects the performance of the assembly.
Innovation Solution
A ball screw assembly design featuring an open nut with an axial opening, a guider, an open shield, and circulators that form a ball circulating race, allowing the nut to pass supporting holders without interference, eliminating the need for resilient mechanisms and maintaining the screw's alignment, thus preventing sagging and enhancing manufacturing precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a supporting holder with a resilient mechanism is provided to prevent screw sagging, then the screw can be supported during operation, but the ball nut and supporting holder may interfere with each other when the ball nut passes the supporting holder position
Solution Approach 1:
The invention extracts the resilient mechanism from the supporting holder, removing the source of interference. The supporting holder is redesigned to be fixed without resilient elements, allowing the ball nut to pass freely through the opening without encountering temporary displacement or interference from the holder's movement.
Solution Approach 2:
The invention segments the supporting holder into a fixed structure with an opening that accommodates the ball nut passage. The holder is divided into regions: a support region that contacts the screw to prevent sagging, and a passage region with an opening that allows the ball nut to pass through without interference.
2Ease of operation
If the supporting holder is temporarily moved away from the screw through a resilient mechanism, then the ball nut can pass the supporting holder position, but the screw may sag due to its weight when the holder is away
Solution Approach 1:
The resilient mechanism is completely removed from the supporting holder. Instead of temporarily moving the holder away, the invention uses a fixed holder with an opening that allows the ball nut to pass through while the holder remains in its supporting position, maintaining screw alignment throughout the passage.
Solution Approach 2:
Instead of moving the supporting holder away to allow passage (as in conventional designs), the invention inverts the approach by keeping the holder fixed and creating an opening in it for the ball nut to pass through. This reverses the conventional logic while solving both the passage and support problems simultaneously.
3Adaptability or versatility
If a resilient mechanism is provided on the supporting holder, then the holder can temporarily move away from the screw, but additional complex mechanisms are required and the screw may encounter deflection
Solution Approach 1:
The resilient mechanism is extracted and removed entirely from the supporting holder structure. The holder is simplified to a fixed structure without any resilient elements, eliminating the complexity associated with resilient mechanisms while maintaining the necessary support function.
Solution Approach 2:
Instead of making the supporting holder movable through resilient mechanisms (conventional approach), the invention inverts the design by making the holder fixed and creating an opening in it. This simplifies the holder structure while still allowing the ball nut to pass through freely.
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 ensures the screw does not sag or deform, maintaining manufacturing precision and performance by allowing the nut to pass supporting holders without interference, and providing a dustproof function while enabling smooth ball circulation.
Implementation Method 1
The ball circulating assembly rolls in the ball circulating race
Implementation Method 2
the friction between the ball nut and the screw can be reduced during the operation
Data Source
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AI summary
A ball screw assembly includes a guider (10), an open nut (20), an open shield (30), a first circulator (40), a second circulator (50), and a ball circulating assembly (60). The open nut (20) is slidably fitted over the guider (10) and includes an axial cylinder (21) having an axial opening (211). An inner spiral channel (2141) of the axial cylinder (21) and a spiral channel (11) of the guider (10) form an inner ball race. The open shield (30) is coaxially fitted over the axial cylinder (21). An inner peripheral wall (31) of the open shield (30) and an outer annular wall (215) of the axial cylinder (21) form an outer spiral ball race. The first circulator (40) and the second circulator (50) are disposed on the axial cylinder (21). The inner ball race, a first curve (41) of the first circulator (40), the outer spiral ball race, and a second curve (51) of the second circulator (50) form a ball circulating race, and the ball circulating assembly (60) rolls in the ball circulating race.