Motor End Cap and Transmission Mechanism for Hammer Drill Mode Transition
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Solution Overview
Problem
Existing drills, hammer drills, and chippers lack an efficient mechanism to seamlessly transition between hammering, rotary, and combined modes of operation, often resulting in suboptimal performance due to complex transmission mechanisms and limited torque management.
Innovation Solution
A battery-powered hammer drill design featuring a transmission mechanism with a mode change sleeve that selectively engages gears to control torque clutch engagement, allowing smooth operation in all three modes by managing torque transfer through a series of interlocking gears and a brushless electric motor with a radial fan for cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a transmission mechanism with multiple gears and mode change sleeve is used to enable three modes of operation, then the adaptability and versatility of the drill is improved, but the device complexity increases
Solution Approach 1:
The transmission mechanism is segmented into distinct functional components: a mode change sleeve with three positions, a torque clutch with multiple engagement states, and separate gear trains for hammering and rotary functions. This segmentation allows each component to handle specific tasks independently, enabling three operational modes through coordinated interaction of simplified subsystems rather than a single complex mechanism.
Solution Approach 2:
The mode change sleeve serves multiple functions: it selects between three operational modes (hammer only, rotary only, combined mode), controls torque clutch engagement, and coordinates gear train selection. The torque clutch also performs multiple roles including torque limitation, mode transition facilitation, and protection against overload. This multi-functionality reduces the number of separate components needed.
2Reliability
If a torque clutch mechanism is used to manage torque transfer between motor and transmission, then the reliability and torque management are improved, but the device complexity increases
Solution Approach 1:
The torque clutch mechanism is merged with the mode change sleeve and gear train selection system. The clutch's engagement and disengagement are directly coupled with the mode change sleeve position, allowing torque management to be integrated with mode selection rather than being a separate control system. This merging reduces overall complexity while maintaining reliable torque management across all three operational modes.
Solution Approach 2:
The torque clutch is designed to automatically engage and disengage based on the mode change sleeve position and operational requirements. The mechanism self-regulates torque transfer without requiring external control inputs, using spring pressure, gear meshing forces, and sleeve position to automatically manage torque distribution between the motor and transmission components.
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
Enables efficient and reliable operation in hammer only, rotary only, and combined hammer and rotary modes by effectively managing torque and cooling the motor, enhancing user control and tool performance.
Implementation Method 1
a brushless electric motor with a radial fan for cooling
Data Source
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AI summary
A drill comprising: a body (2), the body (2) comprising a housing (4, 6, 8) formed internally with at least two chambers (120, 122); a rear handle (14) mounted on the body (2); a tool holder (10) mounted on the front of the body (2); an electric motor (24) mounted in a first chamber (120), the electric motor (24) comprising an end cap (82) attached to a motor housing (70); a transmission mechanism (22) mounted in a second chamber (122) which is in driving connection with the electric motor (24), the transmission mechanism (22) being driven by the electric motor (24) when the electric motor (24) is activated to either impart impacts to and/or rotate a cutting tool when held by the tool holder; characterised in that the end cap (82) engages with the housing (4, 6, 8) to form a separating wall which separates the first and second chambers.