Sweeper Hydraulic Transmission for Consistent Brush Speed

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Solution Overview

Problem

Conventional sweepers with two main wheels are less efficient when navigating curved paths compared to straight lines due to varying motor torque distribution, leading to inconsistent performance.

Innovation Solution

A sweeper design utilizing two main wheels connected to hydraulic pumps in parallel, driving hydraulic motors that power accessories such as brushes and a turbine, ensuring consistent power delivery regardless of the path, with speed multipliers and non-return valves to maintain efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional mechanical transmission (belt or chain) is used to drive accessories from main wheels, then the structure is simple, but the transmission efficiency varies when turning and the system is sensitive to dust

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidtransmission system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies hydraulic transmission by connecting hydraulic pumps to the main wheels and hydraulic motors to the accessories. The hydraulic fluid transmits power from the pumps (driven by wheels) through hoses to the motors (driving brushes and turbine), providing reliable power transmission that is insensitive to dust and maintains consistent performance during turns.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Speed

If gear transmission with speed multiplication is used in each wheel, then the accessory can be driven at appropriate speed, but the brush speed varies significantly when turning

Engineering Contradiction:
Improvebrush rotation speedVSAvoidbrush speed consistency
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The hydraulic system naturally compensates for speed variations during turning. When the sweeper turns, one wheel rotates faster than the other, but the hydraulic fluid distributes power to maintain relatively consistent brush speeds, eliminating the extreme variations caused by direct mechanical gear transmission.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent uses speed multipliers (gear reductions) between the wheel-driven pumps and the accessory-driven motors to optimize operational speeds. The hydraulic system allows independent control of each accessory's speed parameter, maintaining stability even when wheel speeds vary during turning.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If hydraulic transmission with two pumps in parallel is used, then consistent power delivery is achieved during turns, but the system complexity increases

Engineering Contradiction:
Improvesweeping efficiencyVSAvoidhydraulic system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The hydraulic system is segmented into independent modules: two wheel-driven pumps connected in parallel, multiple accessory-driven motors, and connecting hydraulic hoses. This modular segmentation allows consistent power delivery to each accessory independently, maintaining sweeping efficiency during turns while making the system manageable and maintainable.

Inventive Principle:
Principle #1Segmentation

4Power

If non-return valves and flow dividers are added to the hydraulic circuit, then power distribution is optimized, but the device complexity increases

Engineering Contradiction:
Improvepower distribution efficiencyVSAvoidhydraulic circuit complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

Non-return valves and flow dividers act as intermediary components in the hydraulic circuit. The non-return valves prevent backflow and ensure unidirectional power transmission, while flow dividers distribute hydraulic fluid efficiently between parallel pumps and motors, optimizing power distribution without requiring complex control systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2231932B1Sweeper
Publication Date: 2016.12.07 ETAB EMILY
  • EP2231932B1 patent drawingFigure 1a~1b
  • EP2231932B1 patent drawingFigure 2
  • EP2231932B1 patent drawingFigure 3a~3b

AI summary

The present invention relates to a sweeper (100) comprising two main wheels (210a, 210b), at least one accessory (410, 420, 440) especially intended for sweeping or suction, a means of driving said accessory via the main wheels, a dust collection bin (430), said accessory being composed of a brush (420) having a horizontal axle intended for sending the dust into the collection bin (430), the brush (420) having a horizontal axle being rotated by a hydraulic motor (520). The sweeper is noteworthy in that the hydraulic motor (520) is coupled to two hydraulic pumps (560a, 560b), which are connected in parallel and respectively rotated by the two main wheels (210a, 210b) or the hydraulic motor (520) is connected to one hydraulic pump (560c), driven by a differential bridge (240) that is driven by the two main wheels (210a, 210b). By virtue of this hydraulic transmission, the sweeper thus uses its two main wheels, in all circumstances, to drive its accessory or accessories. It operates both when it is moved in a straight line or when it follows a curved trajectory.