Commutator Motor Brush Assembly With Spring-Arm Pre-Clamping
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Solution Overview
Problem
Manufacturing tolerances in the assembly of brush systems for commutator motors can lead to improper clamping of connecting cables, resulting in assembly rejects and increased complexity and cost.
Innovation Solution
A brush system design featuring a flexible spring arm and a spring element that clamps the carbon brush in a pre-assembly position, ensuring it does not interfere with the commutator during assembly, and a longitudinal slot for the connecting cable, allowing for reliable and cost-effective assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constriction is used to hold the connecting cable in the longitudinal slot, then the brush carbon can be retained in the brush shaft, but manufacturing tolerances cause improper clamping and assembly rejects
Solution Approach 1:
The patent changes the geometric parameters of the clamping mechanism by replacing a rigid constriction with a flexible spring arm that has a clamping element. This flexible element can adapt its position and applying force, compensating for manufacturing tolerances in the longitudinal slot and brush shaft dimensions, thereby ensuring reliable clamping without strict tolerance requirements.
Solution Approach 2:
The spring arm acts as an intermediary element between the brush shaft and the brush carbon with connecting cable. Instead of directly constraining the cable in a rigid slot, the spring arm provides a compliant clamping action that mediates the interaction, allowing for tolerance compensation while maintaining secure retention.
2Reliability
If the brush carbon is pre-tensioned with a spring element, then contact with the commutator is maintained, but the brush carbon may collide with the commutator during assembly
Solution Approach 1:
The spring arm is pre-configured in the brush shaft to provide clamping force on the connecting cable, holding the brush carbon in a retracted position before assembly. This preliminary action prevents collision with the commutator during assembly while maintaining the capability for reliable electrical contact once assembled.
Solution Approach 2:
The spring arm provides a dynamic clamping force that can adjust during assembly. The flexible nature of the spring arm allows it to accommodate the brush carbon's movement from the retracted assembly position to the operational contact position, ensuring both assembly ease and contact reliability.
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 design simplifies assembly, reduces rejects, and ensures reliable contact between the carbon brush and commutator, enhancing the manufacturing efficiency and cost-effectiveness of commutator motors.
Implementation Method 1
a spring element (6) which exerts a spring force on the brush carbon (4) in the longitudinal direction of the shaft (5)
Implementation Method 2
a flexible spring arm (13) which rests against the brush carbon (4) in its pre-assembly or parking position (Pv) and which exerts a clamping force on the brush carbon (4) in a shaft transverse direction of the brush shaft (5)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a brush system (1) of a commutator motor (19) comprising: - at least one carbon brush (4) having a contact surface (4a) facing a commutator (3), a bearing surface (4b) opposite this contact surface, and a connection line (7); - a brush shaft (5) receiving the carbon brush (4), which shaft has a longitudinal shaft slot (9) via which the connection line (7) is guided; and - a spring element (6) which exerts a spring force on the carbon brush (4) in its working position (PA) in the longitudinal direction (L) of the shaft, wherein the carbon brush (4) is clamped in the brush shaft (5) in a pre-assembly position (PV) by means of the spring element (6) or by means of a elastically bending spring arm (13).