Elastic Axial Socket Spindle Nut for Zero Clearance Actuator
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Solution Overview
Problem
Existing motor vehicle seat actuators face a clearance issue between the spindle nut and spindle, which affects performance during drive direction changes, and previous attempts to achieve zero clearance have been complex and inefficient.
Innovation Solution
An actuator design featuring a spindle nut with a radially elastic axial socket that engages the spindle, utilizing an elastic element to ensure a zero clearance fit by pushing the internal thread into engagement with the spindle, distributing load and absorbing crash forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional spindle nut and spindle design is used, then the structure is simple, but clearance between the spindle nut and spindle is unavoidable, affecting performance during drive direction changes
Solution Approach 1:
The spindle nut is segmented into a rigid main portion and a radially elastic axial socket portion. This segmentation allows the main portion to maintain structural integrity while the axial socket portion independently deforms radially to eliminate clearance with the spindle, resolving the contradiction between reliability and complexity.
Solution Approach 2:
Different portions of the spindle nut have different mechanical properties: the main portion is rigid to absorb crash forces, while the axial socket portion is radially elastic to achieve zero clearance fit. This local differentiation of material properties enables the system to simultaneously achieve reliability and maintain manageable complexity.
2Manufacturing precision
If previous attempts to achieve zero clearance are implemented, then clearance is eliminated, but the device complexity increases significantly
Solution Approach 1:
The radial elasticity of the axial socket is achieved by changing the physical parameters of the material or structure in that specific region, allowing it to deform radially under the action of the elastic element. This parameter change enables zero clearance fit without requiring complex assembly of multiple precision components.
Solution Approach 2:
The radially elastic axial socket automatically adjusts its radial dimension to eliminate clearance with the spindle through its inherent elastic deformation capability. This self-adjusting mechanism achieves zero clearance fit without requiring complex external adjustment mechanisms or precise pre-setting of multiple components.
3Reliability
If the axial socket is made radially elastic, then zero clearance fit is achieved, but the structural integrity may be compromised
Solution Approach 1:
The segmentation of the spindle nut into a rigid main portion and an elastic axial socket portion isolates the elastic deformation to a localized region. The main portion retains full structural integrity for absorbing crash forces, while the axial socket portion sacrifices some rigidity to enable radial elasticity, thus resolving the contradiction between reliability and strength.
Solution Approach 2:
The radial elasticity is confined to the axial socket portion only, while the main portion maintains its rigid structural integrity. This local quality differentiation ensures that the elastic deformation needed for zero clearance fit does not compromise the overall structural strength and crash force absorption capability of the spindle nut.
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
This design achieves a simple and effective zero clearance interaction between the spindle nut and spindle, enhancing the actuator's performance and durability by ensuring a precise fit and efficient force distribution.
Implementation Method 1
the axial socket is configured to be radially elastic. The actuator further includes an elastic element that fits against the axial socket and pushes the internal thread thereof into engagement with the spindle
Implementation Method 2
the axial socket is configured to be radially elastic... At least one axial socket is provided, which is solidly connected to the main portion and is configured to be radially elastic
Data Source
AI summary
An actuator for a motor vehicle with an electric motor having an output shaft, a gearbox that is connected to the output shaft that includes a spindle nut, and a spindle that engages the spindle nut. The spindle nut comprises one main portion and at least one axial socket. The axial socket: (a) is solidly connected to the main portion, more specifically is integral with the main portion, (b) comprises an internal thread cooperating with the spindle and (c) is configured to be radially elastic. An elastic element is provided which fits against the axial socket and pushes the internal thread thereof into engagement with the spindle.