Power Tool Vibration Isolation and Compact Gear Design
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Solution Overview
Problem
Existing impact drivers transmit vibrations from the drive portion to the circuit board, affecting devices mounted on it, and have a large external gear diameter due to high gear reduction ratios, which is not compact.
Innovation Solution
A power tool design featuring a motor housed in a first housing with a second housing connected through an elastic body, a control circuit board housed in the second housing, and a planetary gear mechanism with a compact internal gear structure that decelerates the motor's rotational force efficiently, reducing vibration transmission and maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the circuit board is housed in the lower end portion of the hand grip connecting to the motor housing, then the structure is simple and easy to manufacture, but vibration generated in the drive portion reaches the circuit board through the hand grip, affecting devices mounted on the circuit board
Solution Approach 1:
The patent introduces a vibration-proof member (elastic element) as an intermediary between the hand grip and the circuit board housing. This mediator absorbs and isolates vibrations from the drive portion, preventing them from reaching the circuit board while maintaining the simple structural arrangement of housing the circuit board in the hand grip area.
2Productivity
If a planetary gear mechanism with one internal gear and two planetary gears is used for deceleration, then the reduction ratio is achieved, but the outer diameter of the internal gear is increased, making the structure less compact
Solution Approach 1:
The patent employs a nested planetary gear configuration where two planetary gears are arranged concentrically within the same vertical plane, with the second planetary gear positioned inside or adjacent to the first. This nesting allows both planetary gears to share the same internal gear, significantly reducing the outer diameter of the internal gear compared to traditional single-stage planetary mechanisms while achieving the required reduction ratio.
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
The solution effectively suppresses vibration transmission to the control circuit board and achieves a high gear reduction ratio in a compact form, protecting the circuit board and allowing for efficient deceleration of the motor's rotational force.
Implementation Method 1
a second housing connecting to the first housing through an elastic body
Implementation Method 2
connecting to the first housing through an elastic body
Data Source
AI summary
To provide a power tool and a rotary impact tool capable of suppressing transmission of vibration to a circuit board and so on from a drive portion connecting to a motor as a vibration generation source. An impact wrench includes a motor housing which houses a motor or a grip housing, a battery holding housing connecting to the motor housing or the grip housing through an elastic body and a control circuit board housed in the battery holding housing for controlling the motor.