Electric Tool Battery Placement for Balanced Handling
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Solution Overview
Problem
Existing handheld electric tools, such as angle grinders, suffer from imbalanced weight distribution due to rear-mounted batteries, leading to ergonomic issues and complex wiring arrangements that generate heat and interfere with user operation.
Innovation Solution
The electric tool design positions the battery between the motor and handle, optimizing balance and ergonomics, with a circuit board adjacent to the motor and short wiring paths, and incorporates a rotatable D-shaped handle for versatile grip and cooling airflow optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the battery is fitted at the rear part of the handle to accommodate large-capacity batteries, then the battery capacity increases, but the centre of gravity of the electric tool is displaced from the optimal balanced position and the user's arm may interfere with the battery
Solution Approach 1:
The battery is repositioned from the rear handle to an intermediate position between the motor and handle, changing its spatial location along the tool's longitudinal axis. This dimensional repositioning allows the battery to contribute to balancing the tool's center of gravity while remaining accessible to the user's hand for operation and battery replacement.
2Ease of manufacture
If the battery is fitted at the rear part of the handle, then the battery can be accommodated, but the circuit board must be arranged close to the battery behind the handle resulting in increased length and complex arrangement of electric wires
Solution Approach 1:
The circuit board is extracted from its traditional position behind the handle and relocated to the front of the handle, near the motor. This separation of the circuit board from the battery location eliminates the need for long wiring runs through the handle, reducing wiring complexity and improving manufacturability.
3Ease of manufacture
If the circuit board is located away from the motor, then the battery can be accommodated at the rear handle, but the wires connecting the motor and circuit board become long and generate heat due to wiring losses
Solution Approach 1:
The circuit board is merged with the motor assembly by positioning it adjacent to the motor at the front of the handle. This consolidation reduces the distance between electrical components, minimizing wire length and thereby reducing heat generation from wiring losses while maintaining ease of manufacture.
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 design enhances user comfort, simplifies maintenance, reduces heat generation, and improves cooling efficiency while maintaining structural balance and versatility in operation.
Implementation Method 1
A fan is provided at a front end of the motor, and at least one air outlet is formed on the gearbox in front of the fan. Thus, a cooling airflow is sucked in through the air inlet formed on the tool housing, flows past the circuit board, and flows downward and rearward to a region behind the motor; the action of the fan then causes the cooling airflow to flow past the motor from behind the motor and be discharged from the outlet on the gearbox at the front side of the motor.
Data Source
Figure 1~2
Figure 3~4
AI summary
An electric tool, comprising a tool housing (21).a motor (3) having a rotating shaft (2), a motor housing (4) accommodating the motor (3), a gearbox (6) arranged at a front side of the motor (3), a main shaft (5) supported by the gearbox (6) and extending in a direction intersecting the rotating shaft (2), a circuit board (10) mounted in the motor housing (4) and located substantially above the motor (3), a battery accommodating part (8) mounted behind the motor housing (4) and used to accommodate a rechargeable battery (7), and a handle (9) mounted behind the battery accommodating part. The electric tool of the present invention has an optimized, balanced tool structure and is more ergonomic, facilitating user operation.