Agricultural Trailer Drum Brake Pin Alignment Against Eccentric Wear
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Solution Overview
Problem
Agricultural trailer axles with traditional drum brakes face misalignment issues due to varying tolerances and thermal shrinkages, leading to reduced braking power, uneven wear, and safety concerns from eccentricity and vibrations.
Innovation Solution
A brake system for trailer axles with a pin having a stem with radial clearance housed in a hole on the brake plate, featuring conjugate surfaces with a rippled finish for precise alignment and locking, ensuring the braking shoes' axis coincides with the axle and brake drum axis, using a tightening nut to secure the pin in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If welding process is used to couple brake plate to axle for constructional simplicity and economy, then manufacturing cost and ease of manufacture are improved, but manufacturing precision and alignment accuracy deteriorate due to greater tolerances and thermal shrinkages
Solution Approach 1:
The patent introduces a brake plate as an intermediary component between the axle and the brake mass. The brake plate includes a mounting surface with a hole that receives the articulating pin, serving as a mediator to accommodate misalignment between the axle and brake components. This intermediary structure absorbs the dimensional variations and thermal shrinkage differences through its design features (hole with clearance, mounting surface geometry), thereby maintaining alignment accuracy without requiring expensive precision welding processes.
2Device complexity
If traditional drum brake structure with shoes pivoted on single pin is used for economy and simplicity, then device complexity is reduced, but reliability deteriorates due to misalignment causing eccentricity, uneven wear, and braking vibrations
Solution Approach 1:
The patent segments the brake mass into distinct components: the brake plate, the articulating pin, and the brake shoes. The articulating pin is a separate removable component that can be precisely fitted into the brake plate's hole. This segmentation allows each component to be manufactured independently with appropriate tolerances, and the assembly process ensures proper alignment. The simplified structure maintains low device complexity while the precise fit between segmented components eliminates eccentricity and ensures reliable braking performance.
3Manufacturing precision
If pin with radial clearance housed in hole is used for alignment adjustment, then manufacturing precision is improved, but device complexity increases due to additional locking means
Solution Approach 1:
The patent incorporates locking means (such as a retaining ring or set screw) as an integral part of the pin-hole assembly design. The locking means is pre-configured to engage with the pin after it is positioned in the hole with radial clearance. This preliminary inclusion of the locking mechanism in the design phase ensures that once the pin is aligned and positioned, it remains securely fixed without requiring additional complex adjustment or locking procedures. The locking means prevents the pin from dislodging while maintaining the achieved alignment precision.
Data Source
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AI summary
The brake for trailer axles of agricultural type (1) comprises at least one axle (10), a wheel hub (20), a brake drum (30) and a brake mass (40) rigidly connected to the axle (10) and comprising at least one brake plate (41), at least two shoes (50 A, 50 B) equipped with friction material (51 A, 51 B) and an articulating pin (70) of the two shoes (50 A, 50 B) having a head (71) and a stem (72), the stem (72) of the pin (70) being removably housed in an axial direction in a hole (200) provided on the brake plate (41), and a tightening nut (75) being further provided for tightening the pin (70) to the hole (200), the stem (72) of the pin (70) is housed with radial clearance in the hole (200) and locking means being provided for locking a distance set between the axis (Y1) of the pin (70) and the axis (Y2) of the hole (200).