Piezoelectric Actuator Transition Piece Positioning
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Solution Overview
Problem
The positioning of the piezoelectric actuator relative to the actuator base in fuel injection systems for internal combustion engines causes stress on copper wires, leading to unreliable electrical contact and potential tearing of the outer electrode over the service life.
Innovation Solution
A metallic transition piece with an injection-molded plastic frame encapsulates the electrical supply lines, providing a reliable positioning mechanism and preventing relative movements between components, ensuring stable electrical contact and preventing wear on the actuator body by isolating the active and passive areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piezoelectric actuator is positioned relative to the actuator base using a plastic-coated copper wire, then electrical contact is established, but relative movements cause stress on the wire leading to unreliable contact and potential tearing over service life
Solution Approach 1:
The patent introduces a transition piece with a metallic base body and plastic overmolding as an intermediary component between the piezoelectric actuator and actuator base. This mediator provides a stable mounting structure with an edge web that positively positions the actuator, eliminating wire stress and ensuring reliable electrical contact throughout the service life.
Solution Approach 2:
The transition piece is segmented into a metallic base body for structural support and electrical conductivity, and a plastic overmolding for positioning and insulation. This segmentation allows each material to perform its optimal function while working together to solve the reliability issue.
2Ease of manufacture
If the actuator body is directly mounted on the actuator base, then assembly is simple, but positioning accuracy deteriorates leading to assembly inaccuracies
Solution Approach 1:
The transition piece serves as a mediator between the actuator body and actuator base, providing precise positioning features through its edge web while maintaining assembly simplicity. The intermediary component integrates positioning, mounting, and electrical functions in a single element.
3Manufacturing precision
If the edge web encloses the actuator body actively, then positioning is improved, but friction and wear occur leading to electrical flashovers
Solution Approach 1:
The edge web is designed to enclose only the passive area of the actuator body, applying the enclosing function locally where it is needed for positioning, while deliberately avoiding contact with the active area to prevent friction and wear that could lead to electrical flashovers.
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
This solution ensures reliable positioning and electrical contact over the service life, preventing breakage of the electrical supply line and assembly inaccuracies, while allowing for effective heat dissipation and preventing electrical flashovers.
Implementation Method 1
The piezoelectric actuator module (2) has an actuator body (3) and a transition piece (4)... reliable positioning of the actuator body relative to the transition piece is achieved and at the same time reliable electrical contact is made possible over the service life
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a piezo-electrical actuator module (2) in particular for fuel injection valves of fuel injection systems for internal combustion engines, comprising an actuator body (3) and at least one transition piece (4). The transition piece (4) has a contact surface (25). According to the invention, the actuator body (3) contacts the contact surface (25) of the transition piece (4) with an end face (26) on one end (28) of the actuator body (3). The transition piece (4) has a frame (6) which surrounds the contact surface (25). The frame (6) positions the actuator body (3) at the end (28) thereof on all sides on the contact surface (25). A reliable electrical contacting of outside electrodes (16) of the actuator body (3) is thus possible, since a relative movement between the actuator body (3) and the transition piece (4) is prevented. The invention additionally relates to a fuel injection valve (1) having such a piezo-electrical actuator module (2).