GB2595701A

GB2595701A - Electrical shield

Info

Publication number: GB2595701A
Application number: GB2008409.1A
Authority: GB
Inventors: William Pye Ian; Maxwell Wasson Robert; Stacey Nicholas
Original assignee: BAE Systems PLC
Current assignee: BAE Systems PLC
Priority date: 2020-06-04
Filing date: 2020-06-04
Publication date: 2021-12-08
Also published as: GB202008409D0

Abstract

An electrical shield 200, suitable for an electrical component, comprises a plurality of faces to shield the electrical component. At least one face of the plurality of faces comprises at least one electrical connector housing 110 machined into at least one face to allow an electrical connection to the electrical component through the electrical shield 200. The plurality of faces and the at least one electrical connector housings 110 are one continuous piece formed from a single piece of conducting material. The shield 200 may comprise five faces. The shield 200 may be configured to comprise a sixth face of a circuit board holding the electrical component. The shield 200 may be formed from aluminium or an alloy thereof. The shield 200 may comprise two internal regions separated by an internal wall (figure 3).

Description

ELECTRICAL SHIELD

BACKGROUND

Electromagentic compatabiltiy (EMC) is the ability of electrical equipment and systems to function acceptably in their electromagnetic environment, by limiting the unintentional generation, propagation and reception of electromagnetic energy which may cause unwanted effects such as electromagnetic interference (EMI) or even physical damage in operational equipment. The goal of EMC is the correct operation of different equipment in a common electromagnetic environment.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a two dimensional illustration of a conventional multi-part electrical shield.

Figures 2A and 2B are two dimensional illustrations of a front and reverse side of a continuous electrical shield according to some examples.

Figure 3 illustrates a continuous shield comprising at least two internal cavities.

DETAILED DESCRIPTION

EMC control is very important in most applications, such as aviation. EMC can be improved by adding shielding to electronic components. Shielding may be added by placing components inside metal containers. However, a limitation of this technique is that the electronic components still need to be connected with other systems electronically and so connector housings are required.

A two dimensional illustration conventional electrical shield is illustrated in Figure 1, using reference number 100. The conventional electrical shield 100 comprises a connector housing 110, connector 130 and a shield plate 105. The connector housing 110 is formed by creating a hole in the shield plate 105 and attaching the connector housing 110 mechanically using at least one mechanical -2 -arrangements 120. The mechanical arrangement 120 may comprise a mixture of fixings and gaskets.

One aim of an electrical shield 100 is to reduce the resistance between the shield plate 105 and the connector housing 110 for a material of choice. One way to achieve this reduction in resistance is to have as small a gap as possible between the connector housing 110 and shield plate 105. This leads to the mechanical arrangements 120 attaching the connector housing 110 needing to be torqued as tight as possible. However, even if the mechanical arrangement is over torqued, there is still an electrically significant gap which forms a weak point in the electrical shielding of the shield plate 105. This cannot be remedied by further tightening of the mechanical arrangements.

Furthermore, requiring high torque on the mechanical arrangements 120 adds to the complexity of the manufacture of the electrical shields. Particularly in aviation applications, the use of a large number of mechanical arrangements such as bolts and nuts increases the risk of a foreign object being left in the electrical component or containers that hold the electrical components. Dropped foreign objects in an aircraft may cause significant damage to the aircraft's components and potentially even risk the life of crew and/or passengers.

Figure 2A illustrates a continuous electrical shield 200 according to some examples. The continuous electrical shield 200 comprises a plurality of faces, although only a single face is shown in Figure 2A. At least one face of the continuous electrical shield 200 comprises an electrical connector housing 110. The electrical connector housing 110 and the continuous electrical shield 200 are machined at the same time from a single piece of conducting material. This ensures that there is no gap at all between the electrical connector housing 110 and the continuous electrical shield 200. The lack of any gap improves the EMC characteristics, and reduces the bonding resistance between the connector housing and the electrical shield. Furthermore, by using a pre-manufactured housing the assembly of the continuous electrical shield 200 with an electrical component is greatly simplified. This removes the risk of over tightened fixings, and reduces the chance of foreign objects being lost inside the apparatus. Figure 2A illustrates a continuous electrical shield 200 without any gaskets, fixings or -3 -other types of mechanical connectors holding the connector housings to the front face of the continuous electrical shield 200.

Figure 2A is a two dimensional illustration of the continuous electrical shield 200. Figure 2B illustrates a reverse side of the continuous electrical shield 200. Figure 2B shows that a wall 210 forms four faces around the electrical connector housing 110. The four faces of the wall 210 together with the front face of the electrical shield form a cavity 220 which the electrical component sits inside. A sixth face to completely enclose the electrical device may be formed by a metallic layer within a circuit board when the electrical device is placed inside the electrical shield. Alternatively a separate conductive enclosing face could be used. Furthermore, the front face could be any one of the faces, it is not limited to being a face comprising connector housings. The faces could also have any shape. In some examples the faces may be curved. The shape of the faces may depend upon the intended application of the continuous electrical shield 200, for example a shape may chosen which maximises the spaced inside the shield based on the available space where the shield will be used. Alternatively, the face shape may be chosen to improve compatibility with other devices, for example a flat shape may be easily stacked without gaps or voids between different shields.

An insert may be inserted into the connector housing. The insert may comprise a plurality of pins (i.e. a "male" insert), or holes (i.e. a "female" insert).

The type of insert may depend upon the components being connected, and standard connector inserts may be used. The inserts may be made of rubber or any other suitable material.

Figure 2B illustrates a continuous electrical shield 200 comprising a single cavity. However, any number of cavities may be formed of any shape during the fabrication process. Figure 3 illustrates a continuous electrical shield 300 according to some examples, comprising at least two cavities. The continuous electrical shield 300 comprises a first cavity 330a formed by first wall 210a. The first cavity encloses a first electrical connector housing 110a. The continuous electrical shield 300 also comprises a second cavity 330b formed by a second wall 210b. The second cavity 330b encloses a second electrical connector 110b and a third electrical connector housing 110c. The first cavity 110a is also -4 -enclosed by the second cavity 110b, however this may not be appropriate in all situations. Multiple cavities allow electrical devices enclosed to be isolated from one another, and/or to increase the shielding of a particular component.

The electrical shields according to some examples are formed from a conductor. The choice of a suitable conductor will depend upon a variety of factors, such as cost of the conductor, required conductivity, and density of the conductor. In some applications, such as aviation, keeping the weight low may be a critical consideration, and so a light conductor, such as aluminium or alloy of aluminium may be favoured. -5 -

Claims

CLAIMS1. An electrical shield for an electrical component, the electrical shield comprising a plurality of faces to shield the electrical component, wherein at least one face of the plurality of faces comprises at least one electrical connector housing machined into the at least once face to allow an electrical connection to the electrical component through the electrical shield, and the plurality of faces and the at least one electrical connector housing are one continuous piece formed from a single piece of conducting material.
2. The electrical shield according to claim 1, wherein the plurality of faces comprises five faces.
3. The electrical shield according to claim 2, wherein a sixth face is configured to be formed by a circuit board holding the electrical component.
4. The electrical shield according to any previous claim, wherein the electrical shield comprises at least two internal regions which are shielded from each other by an internal wall, the internal wall continuous with the plurality of faces and formed from the single piece of conducting material.
5. The electrical shield according to any previous claim, wherein the conducting material comprises one of aluminium, copper or an alloy thereof.
6. An electrical shield for an electrical component, comprising at least one face and an electrical connector housing on least one face, wherein the electrical connector housing and the at least one face are formed without any gap between them.
7. The electrical shield according to claim 6, wherein the at least one face comprises five faces.
8. The electrical shield according to claim 7, wherein a sixth face is configured to be formed by a printed circuit board holding the electrical component.
9. The electrical shield according to any previous claim, wherein the electrical shield comprises at least two internal regions which are shielded from -6 -each other by an internal wall, the internal wall continuous with the at least one face and formed from a single piece of electrically conducting material.
10. The electrical shield according to claim 9, wherein the conducting material is one of aluminium, copper or an alloy thereof.
11. A method to machine an electrical shield, the method comprising: machining a plurality of faces of the electrical shield from a single piece of conducting material; and machining at least one electrical connector housing on the plurality of faces.