Patent Application
20240422922
This application claims priority to EP 23 179 776 filed Jun. 16, 2023, the entire disclosure of which is incorporated by reference.
The present disclosure relates to a joining element for a housing, such as required between adjoining parts of an electronic control unit (ECU) housing to provide electromagnetic compatibility (EMC).
An electronic control unit (ECU) typically comprises a housing for accommodating various electronic devices within, such as a processor chip on a printed circuit board (PCB) and associated wiring between components/devices. The housing is often assembled from two die cast halves that must fit together and serve to provide electromagnetic compatibility (EMC) and electrostatic discharge (ESD) mitigation features to meet regulatory requirements.
The corresponding die cast housing parts may be coupled together by complicated and often expensive EMC/ESD protection solutions, such as gaskets made from polymer having embedded metal elements, in combination with screw fasteners to hold the parts together. A particular consideration is the need to compensate for gaps between contacting edges of the housing parts, which vary depending on the manufacturing tolerances.
The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
The present disclosure seeks to address issues with fitting housing parts together, e.g. while maintaining EMC/ESD protection. At the least, the disclosure herein provides an alternative option for a joining element incorporated into an ECU housing.
According to a first aspect, a joining element is provided according to claim 1. In an example form, the invention entails a resiliently biased joining element, or spring-clip, comprising a first pair of resilient engagement elements or jaws for receiving a first part to be joined; and a second pair of resilient engagement elements or jaws for receiving a second part to be joined to the first part. The configuration is such that the first pair of engagement elements receives and engages with the first part of the housing by a first engagement force, and the second pair of engagement elements receives and engages with the second part of the housing by a second engagement force. In one form, securing the second part by the second pair of engagement elements causes an increase in the force of the first engagement force on the first part. In this way, the engagement forces, determined by the resilient bias of respective pairs of elements, couple the two parts and the gripping force of the first pair of elements is naturally increased by engagement of the second part into the second pair of elements. Likewise, the engagement force of the first pair, against the resilient bias, influences the second engagement force.
In embodiments, the first and second pair of jaws extend from opposite sides of the joining element, e.g. from a common wall or platform forming a backbone of the element. In this way, if the first and second jaws are aligned, so too can first and second parts at a joining seam. However, alternative solutions are possible, where the jaws are offset to accommodate intentionally offset adjoining parts.
In general, the backbone forms a longitudinal axis about which the respective pairs of jaws pivot.
In embodiments, one or both of the resilient jaws/engagement features may include an opening profile that guides the first and second parts respectively to be received thereinto. In other words, a self-positioning feature which may urge proximate edges of the parts into alignment. In this way, the joining element is in the form of an EMC spring able to self-position and compensate any variation in gap found when connecting two halves of a housing. EMC/ESD protection of unit is thereby improved with less restrictive tolerances for parts since the corresponding edges are hidden within the spring clip/engagement features, allowing for gaps/variations to be accommodated.
In embodiments, the joining element is formed from a sheet of material, bent into a continuous shape. In one embodiment, the sheet is formed at a first edge with a first jaw of the first pair of resilient jaws, bent forwardly to form a first jaw of the second pair of resilient jaws, bent backwardly to form a landing/platform/bridge/backbone portion approximately perpendicular to the jaws for, in use, abutting against or proximate an edge of at least one of the parts to be joined, the sheet further bent backwardly to form a second jaw of the second pair of resilient jaws approximately perpendicular to the landing, further bent forwardly to form a second jaw of the first pair of resilient jaws, corresponding to and terminating at a second edge of the sheet. The first pair of jaws may also include an outward bend to form a constriction area for engaging with/gripping the first part to be joined.
In this way, the first and second jaws are generally aligned and have a pair of common upstanding walls separate by the backbone. The second pair of jaws may have a different, e.g. less, depth than the first pair of jaws, although the depth may be the same or greater. The configuration may generally be described as M-shaped, albeit where the central v point of the M is flattened. Alternatively, the profile can be described wherein a closed end of the first pair of resilient elements, opposite an open end that receives and engage with the first part of the housing, forms a U-shaped portion of the unitary profile that comprises the second pair of engagement elements.
In embodiments, the unitary profile is made from sheet material, e.g. spring steel, formed as a continuous spring clip shape, comprising the first and second engagement features/resilient jaws and backbone/common wall therebetween for, in use, abutting against or proximate to an edge of the parts to be joined. The spring may be formed, e.g. by multiple steps of a rolling machine or stamped by multiple steps in a stamping machine, from initial bends and positioning of sheet up to final shape corresponding to an M is formed.
A second broad aspect of the disclosure according to claim 9 recognizes a housing for an ECU. The housing may comprise a cover and a base part, each with upstanding walls configured to face each other at aligning edges and form an enclosure within the housing. Further, the respective upstanding walls of the cover and base part are joined across at least a portion of the respective edges by a joining element according to the first aspect. In embodiments, the joining element provides an engagement/holding function securing between adjoining edges, and optionally further secured by fastening elements through aligned openings of the cover and base part.
In this way, a housing is provided with integral EMC/ESD protection at the seams/joining surfaces of the cover and base part. The housing may comprise a plurality of joining elements accommodated at respective edges of the upstanding walls.
According to a third aspect, a method of assembly is provided according to claim 13. A housing according to the second aspect is assembled by engaging the first pair of jaws of at least one joining element onto an exposed edge of the upstanding wall of either the cover or base part, aligning and engaging an exposed edge of the upstanding wall of the other of the cover or base part with the second pair of jaws of the joining element, applying force to open the second pair of jaws, thereby joining edges of the cover and base part. There may be a plurality of joining elements engaged at an edge via respective first jaws, prior to aligning and engaging respective second jaws of the second part. In a further step, a fastening element is engaged to fix the cover and base parts together, thereby sandwiching joining elements therebetween the edges.
In this way, the joining elements assist to provide a closed housing e.g. that may provide solids or liquid resistance at the seams in addition to an environmental shield. The assembly process eliminates the need for a gasket across at least portions of the joining edge, thereby reducing the bill of materials. The ideal form of (stainless) spring steel, that is not plastically deformable, can achieve small cross sections but where stress can be very high.
According to the foregoing, the problem of complicated and often expensive EMC/ESD protection solutions for corresponding die cast housing parts is solved by an EMC longitudinal spring that allows closure of opening lines between housing parts while, at the same time, reducing costs by relaxing tolerances.
The spring clip style joining element described herein closes longitudinal openings between the housing parts with a self-adapting and self-positioning M-shaped configuration. It positions itself for attachment to both housing parts, firmly connecting them and allowing a gap therebetween to vary due to protruding (jaw) features that are clutching/engaging to grip from both sides, of parts of the upstanding walls beyond the edge. Even if the gap varies during an assembly process, after initial compression the spring joint is secured so opening will not occur.
Accordingly, the invention is directed to a standardized approach for assembling electronic control units, thus streamlining production and potentially avoiding extra cost for design changes. The solution is a simple structural feature but exemplifies a number of benefits, as mentioned above.
Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.
The present disclosure will become more fully understood from the detailed description and the accompanying drawings.
In the drawings, reference numbers may be reused to identify similar and/or identical elements.
The following description presents example embodiments and, together with the drawings, serves to explain principles of the invention. However, the scope of the invention is not intended to be limited to the precise details of the embodiments or exact adherence with all system features and/or method steps, since variations will be apparent to a skilled person and are deemed also to be covered by the description. Terms for components used herein should be given a broad interpretation that also encompasses equivalent functions and features.
In some cases, several alternative terms (synonyms) for structural, system features have been provided but such terms are not intended to be exhaustive. For the avoidance of doubt, any terms separated by the “/” symbol generally refer to alternative “or” expressions where the terms can be used interchangeably. Descriptive terms should also be given the broadest possible interpretation; e.g. the term “comprising” as used in this specification means “consisting at least in part of” such that interpreting each statement in this specification that includes the term “comprising”, features other than that or those prefaced by the term may also be present. Related terms such as “comprise” and “comprises” are to be interpreted in the same manner. Any directional terms such as “vertical”, “horizontal”, “up”, “down”, “sideways”, “upper” and “lower” are used for convenience of explanation usually with reference to the form shown in illustrations and are not intended to be ultimately limiting if an equivalent function can be achieved with an alternative dimension and/or direction. All directional terms are relative to each other.
The description herein refers to embodiments with particular combinations of steps or features, however, it is envisaged that further combinations and cross-combinations of compatible steps or features between embodiments will be possible. Indeed, isolated features may function independently as an invention from other features and not necessarily require implementation as a complete combination.
It will be understood that the illustrated embodiments show uses only for the purposes of explanation. In practice, the invention may be applied to many different configurations, where the embodiment is straightforward for those skilled in the art to implement.
The housing parts may be made from metal e.g. die casted or stamped (with properly flanged/ended upstanding side walls), which results in variations in terms of the accuracy of dimensions/tolerances.
The invention herein facilitates a method of assembling an electronic control unit 10 as illustrated. Specifically, at least one elongate joining element 21, in the form of a resilient clip, is provided which acts as a means to engage and interface between edges 13, 14, 15 and 16, 17, 18 respectively.
At the opposite side of the element 21, proximate and protruding toward upper part 11, a second engagement feature, e.g. pair of opposing jaws 24, is located. The respective jaws 22 and 24 may be connected by a common platform/landing/backbone 25 which is relatively flat and provides a recessed throat, continuous with the upstanding walls of jaws 24.
The assembly state (i) of
By way of example, prior to the state (i) of
During the second step (ii) of
While at state (ii) of
The illustrated configuration ensures that adjoining parts are aligned or urged into alignment. Alternative embodiments may feature engagement features/jaws that are intentionally misaligned, to accommodate an intentional design feature of the parts/housing. In this sense, “alignment” used herein means to be guided into an intended relative position.
Electronic devices can be assembled into the housing in the normal way, prior to closure by the above method. A complete assembly of housing 10 is illustrated by
A housing as described herein can be constructed from known materials, e.g. die cast metal. The resilient joining element/clip of the invention may be formed from a sheet of spring steel or equivalent material which maintains EMC properties for the ECU as a whole, in order to meet regulatory standards.
By way of summary, the disclosure herein explains the function of a joining element, such as to provide electromagnetic shielding of assembled halves of an electronic control unit. The element, e.g. formed in one elongate and continuous piece from spring steel, comprises a first pair of resilient jaws for receiving a first half of the housing, and a second pair of resilient jaws (24) for receiving a second half of the housing. The jaws position and secure the parts in aligned configuration and bridge any gap/variations in the respective adjoining edges. The element is effectively a clip formed in a continuous generally M-shape from a spring steel sheet material, where the legs of the M form the first pair of resilient jaws and the v part of the M forms the second pair of resilient jaws. Although the point of the v is flattened to serve as a backbone portion along the longitudinal length of the clip.
The term non-transitory computer-readable medium does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave). Non-limiting examples of a non-transitory computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).
The term “set” generally means a grouping of one or more elements. The elements of a set do not necessarily need to have any characteristics in common or otherwise belong together. The phrase “at least one of A, B, and C” should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.” The phrase “at least one of A, B, or C” should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23179776 | Jun 2023 | EP | regional |
