Tractor Trailer Spindle Weight Reduction via Tapered Wall Design

Solution Overview

Problem

Existing replacement spindles for tractor and trailer axles are heavy and may inhibit lubricant flow to bearing assemblies, making on-site repairs challenging and inefficient, especially when all four spindles are replaced, leading to significant weight addition and potential maintenance issues.

Innovation Solution

The design features a replacement spindle with a thin inner edge or lip and varying tapers that facilitate lubricant flow and reduce weight, including eight different combinations of profiles and liners that increase wall thickness with load, ensuring strength and weight savings without compromising load-carrying ability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a replacement spindle with increased wall thickness is used to maintain strength and load-carrying ability, then the spindle weight increases, but this may inhibit lubricant flow to bearing assemblies

Engineering Contradiction:

Improvespindle strength and load-carrying abilityVSAvoidspindle weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The spindle incorporates varying wall thicknesses at different locations, with thicker walls at the inner end where strength is most critical and thinner walls at the outer end where lubricant flow is needed. This local differentiation of material distribution optimizes both structural strength and lubricant accessibility without requiring uniform thickness throughout.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention transitions from a uniform wall thickness design to a dimensionally varied design with tapered walls. The wall thickness varies along the axial dimension of the spindle, creating a gradient structure that provides strength where needed while facilitating lubricant flow in other regions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Strength

If a heavy replacement spindle weighing forty pounds or more is used to ensure sufficient strength and factor of safety, then load-carrying ability is maintained, but significant weight addition occurs when all four spindles are replaced

Engineering Contradiction:

Improvespindle strength and factor of safetyVSAvoidtotal weight of four spindles

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The spindle incorporates varying wall thicknesses at different locations, with thicker walls at the inner end where strength is most critical and thinner walls at the outer end where lubricant flow is needed. This local differentiation of material distribution optimizes both structural strength and lubricant accessibility without requiring uniform thickness throughout.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention changes the wall thickness parameter along the axial length of the spindle, transitioning from a constant parameter design to a variable parameter design. This allows optimization of strength-to-weight ratio by concentrating material where stress is highest and reducing material where it is less critical.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If a spindle with uniform wall thickness is used, then manufacturing is simplified, but it cannot simultaneously optimize both strength at the inner end and lubricant flow at the outer end

Engineering Contradiction:

Improvespindle manufacturing simplicityVSAvoidspindle performance adaptability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The spindle incorporates varying wall thicknesses at different locations, with thicker walls at the inner end where strength is most critical and thinner walls at the outer end where lubricant flow is needed. This local differentiation of material distribution optimizes both structural strength and lubricant accessibility without requiring uniform thickness throughout.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8939518B2Tractor and trailer spindle assemblies

Publication Date: 2015.01.27 EBERT JAMES L

AI summary

An improved replacement axle spindle includes a cylindrical wall exhibiting increasing thickness at increasing distances from the inner end which is secured to an axle. The wall thickness increases in correspondence with the load borne by the replacement spindle resulting in no loss of necessary strength and load carrying ability. Several different profiles are embodied in the present invention: a first embodiment utilizes a straight internal taper; a second embodiment utilizes a dual internal taper, first at a small angle and then at a larger angle; another embodiment utilizes a parabolic internal taper and yet another embodiment utilizes a straight external taper. All may be utilized to replace a tractor or a trailer axle spindle. The spindles save weight and facilitate lubricant flow from the tractor differential into the axle roller bearing assemblies after a repair procedure.