Transmission Actuator Coil End-Stop for Quiet Piston Travel
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Solution Overview
Problem
Existing electromagnetic actuators for transmission systems in motor vehicles generate noise and shocks due to the piston's movements between its retracted and deployed positions, which can compromise comfort and the proper functioning of the actuator.
Innovation Solution
The actuator features a surmiled coil with a radial extension that absorbs noise and shocks by providing a piston end-stop and guiding the piston's movement within the actuator's annular space, which is housed in a monobloc case made of magnetic material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston moves between retracted and deployed positions in a traditional electromagnetic actuator, then the actuator can change the coupling state of the differential system, but noise and shocks are generated during piston movement
Solution Approach 1:
The patent introduces a radial extension element as an intermediary component between the piston and the housing. This extension absorbs and dampens the shocks and noises generated during piston movement, acting as a mediator that protects the housing and surrounding components from harmful vibrations while allowing the piston to perform its coupling function.
Solution Approach 2:
The radial extension is designed to protrude into the annular space before the piston reaches its extreme positions. This beforehand cushioning element makes contact with the piston during movement, absorbing shocks and noises before they can propagate to the housing and cause damage or discomfort.
2Object-generated harmful factors
If the coil is overmolded with a radial extension, then noise and shocks are absorbed, but the device complexity increases
Solution Approach 1:
The patent merges the coil assembly with the radial extension by overmolding the coil former to create an integrated structure. The radial extension becomes an inherent part of the coil assembly rather than a separate component, simplifying the overall device structure while maintaining the noise and shock absorption function.
Solution Approach 2:
The radial extension serves multiple functions: it acts as a structural support for the coil, provides noise and shock absorption, and defines the annular space for piston movement. This multi-functionality reduces the need for additional separate components, thereby reducing device complexity.
3Speed
If the piston moves rapidly between positions, then the actuator response time is improved, but shocks and vibrations increase
Solution Approach 1:
The radial extension is positioned to make contact with the piston before it reaches the end of its travel. This beforehand cushioning allows the piston to move rapidly while the extension gradually absorbs the impact, preventing sudden shocks and vibrations even at high speeds.
Solution Approach 2:
The radial extension provides a dynamic cushioning effect that adapts to the piston's movement speed. During rapid movement, the extension absorbs higher impact forces, while during slower movement, it provides minimal resistance, allowing the piston to maintain speed while reducing shocks.
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 design effectively reduces noise and shock during piston movement, enhancing passenger comfort and preventing potential actuator damage by absorbing or mitigating these forces.
Implementation Method 1
an annular coil (5) comprising a winding of conductive wire
Implementation Method 2
the coil being encapsulated by a coating (6)... the radial extension (7) of the coil extending inside this housing (11)... absorb all or part of the noise and shocks of the piston
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~5
AI summary
The present invention provides an actuator (1) for a transmission system, wherein: a casing (2) defines an annular space having axis X in which an annular piston (3) for transmitting an actuating force to a coupling device is housed, the piston (3) being arranged coaxially to the X-axis and being mounted so as to be capable of moving axially along the axis X between a retracted position (R) and a deployed position (D); the casing (2) comprises a radially inner skirt (21), a bottom surface (22) and a radially outer skirt (23); an annular coil (5) comprises a conductor winding, the coil (5) being encapsulated by a coating (6), the coating (6) forming a radial extension (7) defining an end-of-travel stop of the piston (3); the piston (3) is mounted so as to be capable of moving in a recess (11) defined between the coil (5) and the inner skirt (21) or the outer skirt (23) of the casing (2); and the radial extension (7) of the coil (5) extends inside this recess (11).