Lifting Column Transmission Assembly Without Splines or Bearings
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Solution Overview
Problem
Conventional lifting column transmission assemblies are complex and demanding in terms of manufacturing precision and assembly, requiring intricate spline systems that increase production costs and assembly complexity.
Innovation Solution
A simplified transmission assembly using fixed screw rods with retractable cavities and threaded connections, eliminating the need for inner splines and bearings, and incorporating an electric motor-driven actuating device for synchronous rotation of transmission sleeves, which reduces manufacturing complexity and assembly requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a three-stage transmission assembly with large screw rod, small screw rod, and guiding tube is used, then the lifting column achieves height adjustability and moving convenience, but the manufacturing precision requirements become extremely high and the assembly process becomes complex
Solution Approach 1:
The transmission assembly is divided into three independent transmission stages, each with its own screw rod and transmission sleeve. This segmentation allows each component to be manufactured and assembled separately with standardized interfaces, reducing the cumulative precision requirements compared to a single complex transmission mechanism.
Solution Approach 2:
Instead of having the screw rods rotate within fixed guides, the invention inverts the approach by having fixed screw rods with transmission sleeves that rotate around them. This inversion eliminates the need for precision bearings and rotational supports, significantly reducing manufacturing precision requirements while maintaining operational smoothness.
2Stability of the object's composition
If inner splines and outer splines are used for transmission between screw rods and guiding tube, then the transmission mechanism achieves synchronized movement, but the assembly process becomes highly complex and time-consuming
Solution Approach 1:
The invention extracts and eliminates the complex spline systems from the transmission mechanism. Instead of using interlocking splines between multiple components, each transmission stage uses a simple threaded connection between the transmission sleeve and screw rod, dramatically simplifying the assembly process while maintaining reliable synchronized movement through the threaded transmission geometry.
3Measurement precision
If multiple transmission components with splines are used, then the transmission ratio and control precision are improved, but the number of parts increases and manufacturing cost increases
Solution Approach 1:
The invention changes the fundamental transmission parameter from spline-based mechanical interlocking to thread-based rotational-to-linear conversion. This parameter change maintains precise control through the well-defined geometry of threaded connections while reducing the number of parts needed, as each transmission stage requires only a screw rod, transmission sleeve, and nut rather than multiple splined components.
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 solution results in a more straightforward manufacturing process, reduced assembly complexity, and increased extensible and retractable distance with a simpler structure, while ensuring reliable fixation and reduced likelihood of loosening through self-locking threads.
Implementation Method 1
both ends of the second transmission sleeve are in threaded transmission connection with the first screw rod and the second screw rod, respectively
Implementation Method 2
ensuring reliable fixation and reduced likelihood of loosening through self-locking threads
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed are a transmission assembly and a lifting column. The transmission assembly includes a first screw rod, a second screw rod, a first transmission sleeve fitted over the first screw rod, and an actuating device for driving the first transmission sleeve to rotate; an end of the first screw rod proximal to the actuating device is fixed, and an end of the second screw rod distant from the actuating device is fixed; a second transmission sleeve is disposed between the first screw rod and the second screw rod, the second transmission sleeve and the first transmission sleeve are synchronously rotatable and are axially extensible and retractable relative to each other, and both ends of the second transmission sleeve are in threaded transmission connection with the first screw rod and the second screw rod, respectively. Because no inner splines are provided for the first screw rod and the second screw rod, and the two screw rods do not rotate, bearings become unnecessary, such that the transmission assembly has a simpler structure, more convenient for manufacturing and assembling.