Torque Impulse Wrench Coupling for Play-Free Rotor Alignment
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Solution Overview
Problem
The existing torque impulse wrenches with a rigidly interconnected motor rotor and pulse unit suffer from coupling-induced misalignment and require disassembly of the motor and housing to service the pulse unit, leading to reduced torque efficiency and cumbersome maintenance.
Innovation Solution
A coupling design featuring a thread connection and conical surfaces between the motor rotor and inertia drive member, ensuring a rigid, play-free connection and allowing independent removal of the pulse unit from the housing without disassembling the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a central screw axially clamps the coupling between motor rotor and inertia drive member, then the coupling is assembled, but the pulse unit cannot be removed for service without removing the motor rotor and housing parts
Solution Approach 1:
The coupling is divided into two separable parts: a first coupling part integrated with the motor rotor and a second coupling part integrated with the pulse unit. The thread connection joins these separate parts, allowing the pulse unit to be detached for service while leaving the motor rotor in place. This segmentation enables independent access to the pulse unit without complete disassembly.
Solution Approach 2:
The pulse unit is extracted as a separable component from the integrated structure. By making the coupling detachable through the thread connection, the pulse unit can be removed for service and maintenance while the motor rotor remains installed in the housing. This extraction principle allows selective access to the pulse unit without removing the motor.
2Reliability
If a rigid coupling connection is used between motor rotor and inertia drive member, then torque impulse efficiency is maximized, but the coupling may still develop play and misalignment over time
Solution Approach 1:
Conical surfaces are used in the coupling design - specifically a first conical surface on the first coupling part and a second conical surface on the second coupling part. These conical surfaces mate together to provide self-centering and alignment stabilization. The conical geometry inherently resists radial and rotational play better than flat surfaces, maintaining alignment stability while preserving torque impulse efficiency.
Solution Approach 2:
The coupling employs a composite structure combining threaded fastening with conical surface engagement. The thread connection provides axial clamping force while the conical surfaces provide radial and rotational alignment. This composite coupling mechanism addresses both the need for rigid torque transmission and long-term alignment stability.
Data Source
Figure 1~2
AI summary
An impulse wrench comprises a housing (10), an electric motor (16) with a rotor (21), a hydraulic pulse unit (18) with an inertia drive member (26) and an output shaft (27), and a coupling (28) rigidly connecting the motor rotor (21) to the inertia drive member (26) to form an integrated rotating structure, wherein the coupling (28) comprises a male coupling portion (32) on the inertia drive member (26) and a female coupling portion (24) on the motor rotor (21). The male coupling portion (32) is arranged to be received in said female coupling portion (24) to form the coupling (28) and has an external threaded section (25a) for cooperation with an internal threaded section (25b) on the female coupling portion (24). The male coupling portion (32) and the female coupling portion (24) have mating conical surfaces (36, 37) to be axially clamping together by the threaded sections (25a, 25b) on the male and female coupling portions (32, 24) to stabilize and lock the coupling (28).