Electrical system with shielding

An electrical system includes an electrical module including a conductive plate, a casing having a bottom face mounted on a top face of the conductive plate while leaving at least a part of the top face revealed, a shielding including a body intended to at least partly cover the casing, and an electronic circuit board for controlling the components of the casing, intended to cover the shielding in order for the shielding to protect the electronic circuit board from the electromagnetic radiations emitted by the electrical components of the casing in their operation. The shielding further includes at least one tab made of a piece with the body of the shielding and extending downwards so as to come into contact with a respective revealed part.

TECHNICAL FIELD

The present invention relates to the field of the electromagnetic shielding of electrical systems.

TECHNOLOGICAL BACKGROUND

It is known practice to control a power electrical module by means of an electronic circuit board arranged against the electrical module.

Now, the electrical module emits electromagnetic waves which risk disturbing the operation of the electronic circuit board.

To avoid this problem, it is known practice to arrange an electromagnetic shielding between the power electrical module and control electronic circuit board. The shielding is, for example, formed by a substantially planar metal sheet.

The module generally comprises a conductive plate forming an electrical ground for the electrical system. Thus, it may be necessary to connect the shielding (and the electronic circuit board) to the conductive plate to ensure a connection to the electrical ground. To this end, it is known practice to use rods mounted on and intended to extend from the electronic circuit board to the conductive plate, passing through the shielding.

The aim of the invention is to propose an electrical system with shielding of simplified design, while comprising a link, notably an electrical link, between the shielding and the conductive plate.

SUMMARY OF THE INVENTION

To this end, an electrical system is proposed comprising:an electrical module comprising:a conductive plate having a top face,a casing having a bottom face mounted on the top face of the conductive plate while leaving at least a part of the top plate revealed,electrical components arranged in the casing,an electromagnetic shielding comprising a body intended to at least partly cover the casing,an electronic circuit board for controlling the components of the casing, intended to cover the shielding in order for the shielding to protect the electronic circuit board from the electromagnetic radiations emitted by the electrical components of the casing in their operation,
the electrical system being characterized in that the shielding further comprises at least one tab made of a piece with the body of the shielding and extending downwards so as to come into contact with a respective revealed part.

By virtue of the invention, the use of mounted rods is avoided for linking the shielding to the conductive plate. Thus, the electrical system has fewer parts which simplifies its design. Furthermore, the assembly is simplified since it no longer includes a rod mounting step.

Optionally, each tab comprises an end having a bottom face intended to be mounted against the revealed part.

Also optionally, the body and the tab or tabs are formed from one and the same sheet, by cutting and folding of this sheet.

Also optionally, the shielding further comprises at least one arm extending upwards from the body of the shielding and on which the electronic circuit board is intended to rest.

Also optionally, the arm or arms are also formed from the sheet, by cutting and folding of this sheet.

Also optionally, the casing further comprises, for each arm, a finger rising upwards, in particular towards the electronic circuit board, and on which the arm is intended to rest.

Also optionally, the electrical system further comprises an insulating sheet intended to be inserted between the shielding and the electronic circuit board.

Also optionally, the conductive plate forms an electrical ground of the electrical system.

Also optionally, for each revealed part of the conductive plate, the body of the shielding comprises an opening intended to be situated above this revealed part.

Also optionally, the electrical system further comprises:a case comprising:a bottom having a top face against which the bottom face of the conductive plate is intended to be mounted,a cover provided, for each revealed part of the conductive plate, with a rod extending downwards and intended to pass into the opening of the shielding situated above this revealed part, the rod having a bottom end intended to be mounted against a top face of the tab of the shielding intended to come into contact with this revealed part.

In particular, the cover is intended to close the case.

DETAILED DESCRIPTION

Referring toFIGS. 1 and 2, an electrical system100according to the invention will now be described.

Referring toFIG. 1, the electrical system100first of all comprises an electrical module102. The electrical module is, for example, a power electrical module, that is to say one passed through by a current of 1 amp or more. The electrical system100is, for example, included in an inverter or, more generally, in a voltage converter.

The electrical module102firstly comprises a conductive plate104having a top face106and a bottom face108. The conductive plate104is planar and rectangular, and has, for example, a thickness of between 1 and 5 millimeters. The conductive plate104is intended to form an electrical ground of the electrical system100. The conductive plate104can be made of metal, for example of nickel or of copper.

The electrical module102further comprises an insulating casing110fixed to the conductive plate104.

The casing110comprises a body112having a top face114and a bottom face116mounted on the top face106of the conductive plate104. The casing110leaves at least a part118of the top face106revealed. These revealed parts118are therefore the part or parts of the top face106which are free of the casing110.

In the example described, the body112of the casing110comprises a central part and two extensions on two opposite sides of the central part, so as to define four openings124leaving the four corners of the top face106of the conductive plate104revealed.

Electrical components (not represented) are arranged in the casing110. In the example described, the casing110encloses the electrical components. These electrical components are connected to pins126exiting from the top face114of the casing110(in the interests of clarity, only two pins are referenced inFIG. 1). The electrical components are further connected to the conductive plate104, in particular for a link to the ground. The electrical components are, for example, power components, that is to say components that can be passed through by currents of 1 amp or more.

An indentation128is further formed in the top face114of the casing110.

The casing110further comprises at least one finger130extending upwards, that is to say towards the electronic circuit board162which will be described later, from the central part of the body112of the casing110.

The electrical system100further comprises a shielding132.

The shielding132comprises a flat body134intended to at least partly cover the top face114of the casing110.

In the example described, the body134of the shielding132comprises, in a manner similar to the body112of the casing110, a central part and two extensions on two opposite sides of the central part, so as to define, for each revealed part118of the top face106of the conductive plate104, an opening140situated above this revealed part118(and therefore also above the opening124of the casing110for this revealed part118).

The body134of the shielding132comprises a top face142and a bottom face144facing the top face114of the casing110. An indentation146is formed in the top face142of the shielding132. Cut-outs148are further formed in the central part of the body134of the shielding132to allow for the passage of the pins126of the casing110.

The shielding132further comprises, for each revealed part118of the top face106of the conductive plate104, a tab150made of a piece with the body134of the shielding132and extending downwards so as to come into contact with this revealed part118. In the example described, each tab150comprises a vertical leg152. Each tab150further comprises, at the bottom of the leg152, that is to say in the distal portion of the leg152which is not linked to the body134, an end154extending horizontally, that is to say parallel to the top face of the conductive plate104, towards the central part of the body134of the shielding132. The end154has a top face facing the opening140and a bottom face intended to be mounted against the revealed part118. Moreover, a fixing hole is formed in the end154.

The shielding132further comprises, for each finger130of the casing110, an arm156extending upwards, that is to say towards the electronic circuit board162which will be described later, the arm156being made of a piece with the body134of the shielding132and intended to rest on the finger130of the casing110. In the example described, each arm156comprises a vertical upright158and an end160extending horizontally, this end160having a bottom face intended to rest on the finger130of the associated casing110, and a top face intended to receive an electronic circuit board.

In the example described, the body134, the tabs150and the arms156of the shielding124are formed from one and the same sheet, by cutting and folding of this sheet. The sheet has, for example, a thickness of between 0.5 and 1 millimeter.

In particular, the leg152of each tab150is obtained by folding the end of one of the extensions of the body134of the shielding132and the end154is obtained by folding the bottom end of the leg152.

The upright158of each arm156is obtained by folding a tongue attached to the central part of the body134of the shielding132, and the end160of the arm156is obtained by folding the end of the upright158.

The shielding132preferably has a planar symmetry relative to one or two of the front-rear P1and right-left P2vertical planes.

The electrical system100further comprises an electronic circuit board162for controlling the components of the casing110. The electronic circuit board162is intended to rest on the arms156of the shielding132to cover the shielding132. The pins126are intended to reach the electronic circuit board162to be connected to the electronic circuit board162, in order to enable the electronic circuit board162to control the components of the casing110via the pins126.

The shielding132protects the electronic circuit board162from the electromagnetic radiations emitted by the electrical components of the casing110in their operation. For example, the shielding makes it possible to reduce these electromagnetic radiations by 50% on the electronic circuit board162. The shielding132is for example made of steel.

The electrical system100further comprises an insulating plate164inserted between the shielding132and the electronic circuit board162. The insulating plate164is for example made of plastic material. The insulating plate164comprises a top face166, oriented towards the electronic circuit board162, in which an indentation168is formed.

Referring toFIG. 2, the electrical system100further comprises a case202comprising a bottom204having a top face206against which the bottom face108of the conductive plate104is mounted.

A duct208is formed in the bottom204of the case202, in particular under the conductive plate104. A coolant, such as water, is intended to pass through this duct to cool the bottom204of the case202.

The case202further comprises a cover210provided, for each revealed part118of the top face106of the conductive plate104, with a rod212extending downwards, that is to say towards the conductive plate104, from a bottom face of the top wall210. Each rod212is intended to pass alongside the electronic circuit board162, then through the openings of the body of the shielding and of the casing situated above this revealed part118. The rod212has a bottom end intended to be mounted against the top face of the tab mounted against this revealed part118. The rod or rods212serve to keep the shielding132in place.

In the example described, each rod212is pierced in such a way as to form a sleeve intended to receive a screw through the top of the cover, the screw extending into the conductive plate and into the bottom of the case. Preferably, the conductive plate104is not drilled before the cover210is assembled on the conductive plate104. In this case, a self-tapping screw can be used.

By virtue of the above invention, the mounting of the shielding is simplified because a single part is used for the shielding and for the connection to the electrical ground-forming conductive plate.

Moreover, the presence of the indentations128,146,168makes it possible to arrange large components on a bottom face of the electronic circuit board162.

Moreover, the tabs132make it possible to connect the shielding to the conductive plate104, and the arms156make it possible to connect the electronic circuit board162to the conductive plate104via the shielding132. With the conductive plate104forming the electrical ground of the electrical system100, a simple connection of the shielding132and of the electronic circuit board162to the electrical ground is produced.

The present invention is not limited to the embodiments described previously, but is, on the contrary, defined by the ensuing claims. It will in fact be obvious to a person skilled in the art that modifications can be made thereto.

Moreover, the terms used in the claims should not be understood to be limited to the elements of the embodiments described previously, but should, on the contrary, be understood to cover all the equivalent elements that a person skilled in the art can deduce from his or her general knowledge.

LIST OF REFERENCES

106top face of the conductive plate104

108bottom face of the conductive plate104

112body of the casing110

114top face of the casing110

116bottom face of the casing110

118revealed part of the conductive plate104

124openings of the casing110

128indentation of the casing110

130fingers of the casing110

134body of the shielding132

140openings of the shielding132

142top face of the shielding132

144bottom face of the shielding132

146indentation of the shielding132

148cut-outs of the shielding132

150tabs of the shielding132

152legs of the tabs150

154ends of the tabs150

156arms of the shielding132

158uprights of the arms156

160ends of the arms

162electronic circuit board

166top face of the insulating plate164

168indentation of the insulating plate164

204bottom of the case202

206top face of the bottom204

210cover of the case202

212rods of the case202