Impact Wrench Gear Case Pin Structure for Shock Absorption
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Solution Overview
Problem
Existing power tools, such as impact drivers and wrenches, face durability issues due to shock transmission to planetary gears and internal gears during abnormal impact force operations, potentially causing damage.
Innovation Solution
Incorporating a design with a sun gear, planetary gear, internal gear, and a gear case with recesses and pins that allow for elastic deformation to absorb shock, and using a brushless motor with a spindle and anvil mechanism to reduce stress on the gears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a planetary gear mechanism is used to reduce output shaft speed, then the output shaft can rotate at a lower speed for tightening operations, but shock during abnormal impact force operations is transmitted to the planetary gears and internal gear, potentially damaging these gears
Solution Approach 1:
The patent introduces a shock-absorbing mechanism comprising a shock-absorbing member and a resilient member positioned between the internal gear and the gear case. This mechanism is designed to absorb shock before it reaches the planetary gears and internal gear, preventing damage during abnormal impact force operations. The resilient member deforms elastically under shock loads, cushioning the impact and protecting the gear mechanism.
Solution Approach 2:
The patent employs a shock-absorbing member as an intermediary element between the internal gear and the gear case. This mediator absorbs and dissipates shock energy, preventing direct transmission of harmful forces to the planetary gears and internal gear. The resilient member acts as a buffer, isolating the gear mechanism from abnormal impact forces.
2Device complexity
If rigid connection between internal gear and gear case is used, then structural simplicity is maintained, but shock transmission damages the gear mechanism
Solution Approach 1:
The patent changes the mechanical parameter of the connection between the internal gear and gear case from rigid to resilient. By introducing a resilient member with specific elastic properties, the connection can maintain structural simplicity while providing shock absorption capabilities. The resilient member's deformation characteristics are optimized to absorb shock energy without compromising the overall structural simplicity of the device.
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 enhances the durability of the reduction mechanism by effectively absorbing shock and reducing the likelihood of damage to planetary gears and internal gears, thereby improving the tool's operational reliability.
Implementation Method 1
the pin being elastically deformable when the internal gear rotates with respect to the gear case
Implementation Method 2
the elastic piece deforms elastically in a circumferential direction of the internal gear to allow the tab member to come in contact with the receiver
Data Source
AI summary
The durability of a reduction mechanism is improved. An impact wrench includes a brushless motor, a sun gear rotatable by the brushless motor, a planetary gear meshing with the sun gear, an internal gear meshing with the planetary gear and having a first recess on an outer circumference, a gear case holding the internal gear and having a second recess on an inner circumference, a spindle holding the planetary gear, and a pin disposed in the first recess and in the second recess.