GB1587985A

GB1587985A - Electronic control module

Info

Publication number: GB1587985A
Application number: GB1302878A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1977-06-04
Filing date: 1978-04-04
Publication date: 1981-04-15
Also published as: FR2393507B3; DE2725340A1; FR2393507A1; JPS543266A; DE2725340C2

Description

(54) ELECTRONIC CONTROL MODULE (71) We, ROBERT BOSCH GMBH, a German company, of Postfach 50, 7 Stuttgart 1, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to an electronic control device of the kind used for switching and control purposes in motor vehicles.

Such a module comprises a housing in which a circuit board, carrying electronic circuits and components, is supported. The circuit board carries components which dissipate and emit heat, and the heat so emitted needs to be conducted away.

Thus, in known modules, the components which emit heat are riveted to associated heat sinks. The heat sinks in turn have a mounting lug which is mounted on the housing. Despite the use of heat sinks, the dissipated heat is conducted away at a location spaced too far away from the components in which the dissipated heat is produced.

Further, problems regarding installation keep arising which are caused by manufacturing tolerances in the formation of the mounting holes in the circuit board and the housing.

There is provided by the present invention an electronic control module comprising a housing in which a circuit board, carrying electronic circuits, and components at least one of which is a heat-emitting component, are supported, the or each heatemitting component being mounted spaced from the circuit board, wherein the circuit board is provided with holes and the housing with mounting projections which protrude through the holes with a clearance and which, at a location of a heat-emitting component, mount the component so that heat emitted thereby is conducted from the component to the mounting projections and thereby dissipated by the housing; and wherein spacers are attached to the circuit board and to the projections and support the board indirectly on the projections and spaced from the or each heat emitting component.

By comparison with the known devices, the module of the present invention has the advantage that the dissipated heat which is to be conducted away from the electronic components concerned is conducted away directly to the part which acts as a heat sink, and the circuit board is mounted in the housing so as to compensate for tolerances.

Another advantage is that the invention makes it possible to dispose conductor paths and further components around the components which emit the heat, and thus to reduce the circuit board to one which is as small as possible. Further, the spacers disposed on the circuit board ensure the required positioning of the circuit board in the housing and the seating of the heatdissipating components therein.

An embodiment of an electronic control module according to the invention is shown in the drawing.

Figure 1 is a longitudinal section through the module, and Figure 2 shows a portion of the module in the direction of the arrow II in Figure 1.

Referring to the drawings, the module comprises a housing 1 which is made of die cast metal and in which mounting projections 2 are integrally cast. A circuit board 3 is supported in the housing 1. Conductor paths are disposed on the board 3 in a known manner, and holes 4 and 5 are formed in the board 3. The holes 4 are located in the region of the conductor paths and accommodate connecting conductors 6 of electronic components. The connecting conductors 6 are connected to the conductor paths in a manner known per se. Electronic components such as component 7, which emit dissipated heat, are disposed spaced at a distance above the circuit board 3. The mounting projections 2 protrude through the holes 5. In this case, the diameter of the holes 5 is greater than the diameter of the mounting projections 2 in the region thereof at the height of the circuit board 3.

The component 7 has a housing formed from a connector plate 8 and a cover cap 9.

Two mounting lugs 10 are formed on the late 8, each having a mounting hole 11.

The electric connecting conductors 6 protrude from the underneath side of the connector plate 8. In the embodiment shown, sixteen connecting conductors 6 are provided which are disposed so as to form a square.

A spacer 13 for the circuit board is mounted on the plate 8. The spacer 13 has substantially the same outline as the plate 8, and has holes 14 which coincide with the mounting holes 11. In addition, the spacer 13 is apertured to provide a reinforcing edge 15 around but spaced from the cover cap 9.

The spacer 13 comprises two angularly curved spacer lugs 16. They each have a supporting section 17 which protrudes beyond the under side of the plate 8 to an extent which corresponds to the distance which is to be kept between the plate 8 and the circuit board 3. The free ends 18 of the lugs 17 are inserted into slots in the circuit board 3 and are curved round on the under side of the board. Thus, the circuit board is mounted by the spacer lugs at a distance from plate 8 determined by the lugs. The spacer is welded to the support plate 8 at two places 19 on each lug 10 of the spacer.

At each of its extensions which lie on the securing flaps 10 of the component 7, the spacer 13 is provided with two welding places and is welded at these places to the component 7.

Each mounting projection 2 has a supporting shoulder 2 and a free end portion 1.The circuit board 3, which is completely pre-assembled with electronic circuits and all the components, is placed over the mounting projections 2. The projections 2 protrude through the holes 5 of the circuit board, and the free ends of the projections protrude through the holes 11 and 14 in the plate 8 and spacer 13, so that the plate 8 lies on the supporting shoulder 20 of the mounting projections 2. The spacer is then riveted to the free ends of the mounting projections and thus secures plate 8. The heat dissipated by component 7 is thereby conducted away directly from the plate 8 to the mounting projections 2 and thus to the housing 1. In addition, the mounting of the circuit board 3 in the housing 1 is free from stresses which are caused by manufacturing tolerances in the housing 1 and circuit board 3, since the circuit board 3 is not mounted directly on the housing 1.

A modified spacer is used for the mounting of the circuit board in the region thereof where there is no component such as component 7. This spacer is a bush-shaped spacer 22, which is made of insulating material and has a supporting edge 23. An axial bore 24 in the spacer 22 has a widened section 25 at the end portion of the spacer 22 at which the supporting edge 23 is located. The transition of the bore 24 into the section 25 is designed as an annular shoulder 26. In the region of the section 25, three resilient projections 27 are provided. The projections extend from the supporting edge 23 and have a portion which protrudes obliquely into the section 25 and a free end 28 which runs outwardly substantially at right angles to the oblique portion, and has a chamfer 29 on the side remote from the supporting edge 23.

The spacer 23 is inserted into a hole 5 in the circuit board from the under-side of the circuit board, so that the edge of the hole 5 presses against the chamfer 29 at the ends 28 of the projections 27 and swivels the projections 27 to some extent into the section 25 until the circuit board 3 is positioned beyond the ends 28 and lies on the supporting edge 23. The projections 27 spring back and the spacer 22 is thus engaged on the circuit board 3. The circuit board is then placed above the mounting projections 2 and lowered down thereonto so that the spacer 22 is pressed onto the end portion 21 of the projection 2. During this downward movement, the end portion 21 acts to swivel the projections 27 outwardly so that the ends 28 of the projections 2 abut on the conductor plate 3. Then the spacer 22 lies with the shoulder 26 on the supporting shoulder 20 of the mounting projection 2. A washer 30 is placed upon the end portion 21 of the mounting projection 2, and the end portion 21 thereafter riveted.

For the mounting of the circuit board, the mounting projections 2 may be provided with a supporting shoulder 20 at the same height irrespective of the type of spacers 13, 22 used. The circuit board, by this means, is always supported at the same level.

WHAT WE CLAIM IS:- 1. An electronic control module comprising a housing in which a circuit board, carrying electronic circuits, and components at least one of which is a heat-emitting component, are supported, the or each heatemitting component being mounted spaced from the circuit board, wherein the circuit board is provided with holes and the housing with mounting projections which protrude through the holes with a clearance and which, at a location of a heat-emitting component, mount the component so that heat emitted thereby is conducted from the component to the mounting projections and thereby dissipated by the housing; and wherein spacers are attached to the circuit board and to the projections and support the board indirectly on the projections and spaced from the or each heat emitting component.

2. A module according to claim 1, wherein each mounting projection has a

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Two mounting lugs 10 are formed on the late 8, each having a mounting hole 11. The electric connecting conductors 6 protrude from the underneath side of the connector plate 8. In the embodiment shown, sixteen connecting conductors 6 are provided which are disposed so as to form a square. A spacer 13 for the circuit board is mounted on the plate 8. The spacer 13 has substantially the same outline as the plate 8, and has holes 14 which coincide with the mounting holes 11. In addition, the spacer 13 is apertured to provide a reinforcing edge 15 around but spaced from the cover cap 9. The spacer 13 comprises two angularly curved spacer lugs 16. They each have a supporting section 17 which protrudes beyond the under side of the plate 8 to an extent which corresponds to the distance which is to be kept between the plate 8 and the circuit board 3. The free ends 18 of the lugs 17 are inserted into slots in the circuit board 3 and are curved round on the under side of the board. Thus, the circuit board is mounted by the spacer lugs at a distance from plate 8 determined by the lugs. The spacer is welded to the support plate 8 at two places 19 on each lug 10 of the spacer. At each of its extensions which lie on the securing flaps 10 of the component 7, the spacer 13 is provided with two welding places and is welded at these places to the component 7. Each mounting projection 2 has a supporting shoulder 2 and a free end portion 1.The circuit board 3, which is completely pre-assembled with electronic circuits and all the components, is placed over the mounting projections 2. The projections 2 protrude through the holes 5 of the circuit board, and the free ends of the projections protrude through the holes 11 and 14 in the plate 8 and spacer 13, so that the plate 8 lies on the supporting shoulder 20 of the mounting projections 2. The spacer is then riveted to the free ends of the mounting projections and thus secures plate 8. The heat dissipated by component 7 is thereby conducted away directly from the plate 8 to the mounting projections 2 and thus to the housing 1. In addition, the mounting of the circuit board 3 in the housing 1 is free from stresses which are caused by manufacturing tolerances in the housing 1 and circuit board 3, since the circuit board 3 is not mounted directly on the housing 1. A modified spacer is used for the mounting of the circuit board in the region thereof where there is no component such as component 7. This spacer is a bush-shaped spacer 22, which is made of insulating material and has a supporting edge 23. An axial bore 24 in the spacer 22 has a widened section 25 at the end portion of the spacer 22 at which the supporting edge 23 is located. The transition of the bore 24 into the section 25 is designed as an annular shoulder 26. In the region of the section 25, three resilient projections 27 are provided. The projections extend from the supporting edge 23 and have a portion which protrudes obliquely into the section 25 and a free end 28 which runs outwardly substantially at right angles to the oblique portion, and has a chamfer 29 on the side remote from the supporting edge 23. The spacer 23 is inserted into a hole 5 in the circuit board from the under-side of the circuit board, so that the edge of the hole 5 presses against the chamfer 29 at the ends 28 of the projections 27 and swivels the projections 27 to some extent into the section 25 until the circuit board 3 is positioned beyond the ends 28 and lies on the supporting edge 23. The projections 27 spring back and the spacer 22 is thus engaged on the circuit board 3. The circuit board is then placed above the mounting projections 2 and lowered down thereonto so that the spacer 22 is pressed onto the end portion 21 of the projection 2. During this downward movement, the end portion 21 acts to swivel the projections 27 outwardly so that the ends 28 of the projections 2 abut on the conductor plate 3. Then the spacer 22 lies with the shoulder 26 on the supporting shoulder 20 of the mounting projection 2. A washer 30 is placed upon the end portion 21 of the mounting projection 2, and the end portion 21 thereafter riveted. For the mounting of the circuit board, the mounting projections 2 may be provided with a supporting shoulder 20 at the same height irrespective of the type of spacers 13, 22 used. The circuit board, by this means, is always supported at the same level. WHAT WE CLAIM IS:-

1. An electronic control module comprising a housing in which a circuit board, carrying electronic circuits, and components at least one of which is a heat-emitting component, are supported, the or each heatemitting component being mounted spaced from the circuit board, wherein the circuit board is provided with holes and the housing with mounting projections which protrude through the holes with a clearance and which, at a location of a heat-emitting component, mount the component so that heat emitted thereby is conducted from the component to the mounting projections and thereby dissipated by the housing; and wherein spacers are attached to the circuit board and to the projections and support the board indirectly on the projections and spaced from the or each heat emitting component.

2. A module according to claim 1, wherein each mounting projection has a

supporting shoulder which determines the position in relation to the housing the spacers support the board from the projections.

3. A module according to claim 1 or 2, wherein each spacer is fixed in place by a rivet received in the free end of the respective mounting projection.

4. A module according to any of claims 1 to 3, wherein the spacer employed to mount the circuit board at the or each location of a heat-dissipating component is carried on and secured to a support plate on which the heat-dissipating component or a respective one thereof is carried, the support plate and the spacer bearing a hole at each of two opposite sides thereof, the holes of the spacer and the support plate at each said side thereof being aligned and admitting therethrough a housing projection, and the spacer bearing spacing lugs which extend beyond the side of the support plate remote from that supporting the spacer to engage with the circuit board and hold the board in position spaced from the support plate.

5. A module according to claim 4, wherein the support plate and the spacer are each formed with oppositely disposed lugs in which respectively said holes are formed.

6. A module according to claim 4 or 5, wherein the spacer is welded to the support plate.

7. A module according to claim 4, 5 or 6, wherein the spacer has a reinforcing edge which passes round the heat-dissipating component or the respective one thereof, spaced from the component.

8. A module according to any of claims 1 to 7, wherein the spacer used to mount the circuit board at a location other than that of a heat-dissipating component of the circuit, comprises a bush-shaped member bearing a hole admitting a housing projection therethrough, and resiliently displaceable parts which engages with the circuit board to hold it in position in relation to the spacer.

9. A module according to claim 8, wherein said spacer used to mount the circuit board at a location other than that of a heat-dissipating component, has a shoulder, and the housing projection a shoulder on which the spacer shoulder is supported.

10. A module according to claim 8 or 9, wherein said resiliently displaceable parts comprise resilient notched projections which engage edge sections of the hole in the circuit board through which the housing projection passes.

11. An electronic control module substantially as hereinbefore described with reference to the accompanying drawings.