Motorcycle Clutch Oil Filter Layout for Easier Maintenance

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Solution Overview

Problem

The maintenance of oil filters in motorcycle power units is inefficient due to the need for extensive disassembly, which complicates access and increases maintenance time.

Innovation Solution

The configuration of the straddle vehicle includes a power unit case with the primary and secondary filters mounted on the bottom surface, covered by an oil pan, allowing easy access and a compact design that reduces the time required for the main clutch to become operational by using separate pumps for the clutch and engine, and a bypass passage to minimize energy loss through the primary filter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the primary filter is placed in the oil pan and the secondary filter is disposed inside the crankcase, then the filters are protected and integrated into the power unit, but the power unit needs to be disassembled extensively for maintenance, reducing maintenance efficiency

Engineering Contradiction:
Improvefilter protectionVSAvoidmaintenance accessibility
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The power unit is divided into modular components with the filters mounted on the bottom surface of the power unit case, allowing the oil pan to be removed independently for filter maintenance without disassembling the entire power unit. This segmentation enables selective access to maintenance components while preserving the integrated design for operation.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single pump is used for both the clutch and the prime mover, then the device complexity is reduced, but the time required for the main clutch to become operational increases during start-up

Engineering Contradiction:
Improvepump configurationVSAvoidclutch operational delay
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The single pump system is segmented into two independent pumps: a clutch-dedicated pump that supplies hydraulic oil exclusively to the main clutch, and a prime mover-dedicated pump for the engine. This allows the clutch pump to build hydraulic pressure independently during start-up, reducing the delay before the clutch becomes operational while maintaining manageable system complexity through functional separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clutch-dedicated pump operates independently from engine start-up to preliminarily build hydraulic pressure in the clutch system before the engine is fully operational. This preliminary action ensures the main clutch is ready for engagement without waiting for the engine-driven pump to reach sufficient pressure, reducing operational delay.

Inventive Principle:
Principle #10Preliminary action

3Volume of moving object

If the filters are mounted on the bottom surface of the power unit case and covered by the oil pan, then a compact design is achieved, but the filters become inaccessible without removing the oil pan

Engineering Contradiction:
Improvepower unit compactnessVSAvoidfilter accessibility
Core Design Contradiction:
Volume of moving objectVSEase of repair

Solution Approach 1:

The oil pan is designed as a removable cover that segments the access path to the filters. By mounting the filters on the bottom surface of the power unit case and covering them with the removable oil pan, the design achieves compactness while enabling filter access through simple oil pan removal rather than extensive disassembly, balancing compactness with maintenance ease.

Inventive Principle:
Principle #1Segmentation

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 configuration improves maintenance efficiency by making filters easily accessible and reduces the time for the main clutch to become operational, while maintaining a compact vehicle design.

Implementation Method 1

a clutch-dedicated pump that sucks the oil from the oil pan and that discharges the sucked oil as a hydraulic oil toward an oil control valve unit

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

a primary filter disposed in an oil passage between the oil pan and the clutch-dedicated pump; and a secondary filter disposed in an oil passage between the clutch-dedicated pump and the oil control valve unit

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 3

an oil pan mounted beneath the power unit case and retaining an oil

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3760844B1Straddle vehicle
Publication Date: 2023.04.26 KAWASAKI MOTORS LTD
  • EP3760844B1 patent drawingFigure 1
  • EP3760844B1 patent drawingFigure 2
  • EP3760844B1 patent drawingFigure 3

AI summary

A straddle vehicle (1) includes: a prime mover (E, M); a hydraulically actuated main clutch (13); an oil control valve unit (24); a power unit case (14) accommodating at least the main clutch (13); an oil pan (45) mounted beneath the power unit case (14); a clutch-dedicated pump (PI); a primary filter (61) disposed in an oil passage between the oil pan (45) and the clutch-dedicated pump (PI); and a secondary filter (63) disposed in an oil passage between the clutch-dedicated pump (PI) and the oil control valve unit (24). The primary filter (61) and the secondary filter (63) are mounted on a bottom surface of the power unit case (14) and covered from below by the oil pan (45).