Variable-Angle Fan Mechanism for Working Machine Airflow Control
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Solution Overview
Problem
Existing fan systems in working machines require complex hydraulic circuits and are prone to damage due to stress concentration at the rotary blades, complicating the device structure.
Innovation Solution
A fan system with a central shaft, rotary blades, and an angle change mechanism that includes a movable member and conversion mechanism to adjust blade angles, using insertion members and fixing members to prevent damage and simplify the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a hydraulic circuit is provided to control switching of a switching valve that switches the rotation direction of a hydraulic motor, then the rotation direction of the fan can be switched between normal and reverse directions, but the device structure becomes complicated
Solution Approach 1:
The invention extracts and eliminates the complex hydraulic circuit system by directly connecting the electric motor to the fan. The switching valve and hydraulic motor are removed from the system, keeping only the essential function of driving the fan while simplifying the overall structure.
Solution Approach 2:
The invention replaces the hydraulic mechanical system with an direct electric motor-driven system. The electric motor directly drives the fan through a simplified transmission mechanism, substituting the complex hydraulic actuation system with a more straightforward electrical-mechanical drive system.
2Adaptability or versatility
If gears are provided at the proximal ends of the rotary blades and the attachment angles are changed by rotating the gears, then the blade angles can be adjusted, but the proximal ends of the rotary blades are likely to be damaged due to stress concentration
Solution Approach 1:
The invention segments the blade assembly into modular components: the rotary blade, the holding member, and the angle adjustment mechanism. This segmentation allows the blade to be adjusted to different angles while distributing mechanical stresses across multiple components rather than concentrating them at the proximal end.
Solution Approach 2:
The invention introduces a holding member as an intermediary component between the rotary blade and the angle adjustment mechanism. This holding member acts as a mediator that transfers and distributes the adjustment forces, preventing direct stress concentration at the blade's proximal end while enabling smooth angle changes.
3Ease of operation
If the attachment angles of rotary blades are changed by rotating gears at the proximal ends, then airflow direction can be changed, but stress concentration occurs at the proximal ends of the rotary blades
Solution Approach 1:
The blade assembly is segmented into distinct functional components including the rotary blade, holding member, and angle adjustment mechanism. This segmentation distributes the mechanical loads and stresses across multiple components, eliminating stress concentration at the blade proximal end while maintaining ease of operation for airflow direction control.
Solution Approach 2:
A holding member is introduced as an intermediary component that mediates between the angle adjustment mechanism and the rotary blade. This intermediary distributes the adjustment forces and reduces stress concentration, enabling smooth and easy airflow direction control without compromising blade durability.
Data Source
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AI summary
A working machine (1) includes a fan (15) to generate a first airflow to cool one or more apparatuses in a machine body (2), and a second airflow in a direction different from a direction of the first airflow. The fan (15) includes a central shaft (16) to rotate about an axis (X1), rotary blades (17) each extending in a radial direction of the central shaft (16), and an angle change mechanism to change an angle of each rotary blade (17) relative to the central shaft (16) by turning the rotary blade (17) about an axis (Z2) extending in the radial direction. The angle change mechanism includes a movable member (31) movable in an axial direction of the central shaft (16), and a conversion mechanism to convert movement of the movable member (31) into turning movement of the rotary blades (17). The conversion mechanism includes insertion members (33) each inserted in the corresponding rotary blade (17) in the corresponding radial direction, fixing members (34) to each fix the corresponding rotary blade (17) and the corresponding insertion member (33) to each other, and a turning mechanism to turn each insertion member (33) about the corresponding axis (Z2) extending in the corresponding radial direction as the movable member (31) moves.