Hammer Mechanism Switching Support to Reduce Gear Case Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hammer driver-drills experience premature wear of the metal case due to microvibrations when the hammer-switching member is activated, leading to reduced durability.
Innovation Solution
Incorporating a resin (polymer) receiving member that holds and supports the switching member, allowing it to move axially, thereby reducing direct impact on the metal case and absorbing vibrations, while maintaining the switching member's functionality between different operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hammer-switching member is held directly in the metal case, then the switching member can be securely positioned, but the metal case experiences microvibrations and premature wear
Solution Approach 1:
A resin receiving member is introduced as an intermediary between the metal case and the hammer-switching member. The receiving member has a through-hole that guides the switching member's movement while the resin material absorbs microvibrations, preventing them from being transmitted to the metal case and causing wear.
Solution Approach 2:
The material of the receiving member is changed from metal to resin, which has different vibrational characteristics. The resin material's damping properties change the vibration transmission parameters, reducing the amplitude and frequency of microvibrations reaching the metal case.
2Duration of action of stationary object
If the receiving member is made of resin, then vibrations are absorbed and wear is reduced, but the structural strength may be compromised
Solution Approach 1:
The resin receiving member is designed with specific local structural features including a through-hole for guiding the switching member and engagement features that interface with both the case and the switching member. This localized structural optimization provides sufficient strength at critical points while maintaining the overall vibration-absorbing resin construction.
Solution Approach 2:
The receiving member can be designed as a composite structure combining resin with reinforcing elements, or the resin itself can be formulated with enhanced mechanical properties while maintaining its vibration-damping characteristics.
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 resin receiving members absorb vibrations, reducing wear on the metal case and enhancing the durability of the power tool by acting as a cushion, even when the hammer-switching levers vibrate during hammering mode.
Implementation Method 1
The resin receiving members absorb vibrations, reducing wear on the metal case and enhancing the durability of the power tool by acting as a cushion
Data Source
AI summary
A power tool, such as a hammer driver-drill (1), includes a spindle (26) that is axially and rotatable supported inside a metal gear case (41). A first cam (83) is affixed to the spindle so as to rotate therewith and is housed in the gear case (41). A second cam (84) is disposed around spindle such that it is rotatable separately with respect to the spindle and can be brought into contact with the first cam. Hammer-switching levers (95) are movable relative to the gear case between an advanced position, at which rotation of the second cam is restricted (blocked), and a retracted position, at which the rotational restriction on the second cam is released. Receiving members (89) are respectively interposed between the gear case and the hammer-switching levers and are configured to absorb vibration generated when a hammering operation is being performed using the power tool.