GB2259409A

GB2259409A - Control device in which transmission of sound is damped

Info

Publication number: GB2259409A
Application number: GB9218252A
Authority: GB
Inventors: Michael Von Buttlar
Original assignee: Hella KGaA Huek and Co
Current assignee: Hella GmbH and Co KGaA
Priority date: 1991-09-07
Filing date: 1992-08-27
Publication date: 1993-03-10
Anticipated expiration: 2012-08-27
Also published as: GB2259409B; DE9111118U1; GB9218252D0

Abstract

A control device for a motor vehicle has a housing (G) containing a printed circuit board (L) on which is mounted an electrical component (181) generating structure-borne sound. An external plug connection (A) mounted in an end plate (S) of the housing is electrically and mechanically connected to the printed circuit board. Transmission of sound from the electrical component (181) is limited by a resilient damping ring (R) through which the plug connection is mounted in the end plate and by a resilient damping element (E) through which the printed circuit board bears on the housing. <IMAGE>

Description

CONTROL DEVICE This invention relates to a control device eg.

for use in motor vehicles.

German application laid open for inspection DE 2338499 Al discloses a control device for motor vehicles which has a housing or casing closed off by an end plate which is formed as an electrical plug connection and in which mutually insulated electrical plug components are arranged. A printed circuit board carrying electrical and/or electronic components is located within the casing and the electrical plug components are electrically connected to the conductor lines on the printed circuit board. In addition the end plate formed as plug connection is mechanically attached to the printed circuit board. Electrical components, namely electromagnetic relays, are mounted on the printed circuit board and actuation of these relays causes structure-borne sound to be generated.

This known form of a control device for motor vehicles is found to have the drawback that the structureborne sound generated by the electrical components is transmitted to the casing without damping, so that upon operation of the control device and those components on the printed circuit board, the structure-borne sound is transmitted through the casing of the control device to the vehicle body on which the casing is mounted. This can produce a disagreeable noise effect because, as is known, the bodywork of a motor vehicle is a particularly good conductor of sound.

It is an object of the present invention to provide a control device for motor vehicles comprising electrical components generating structure-borne sound in which the transmission of the sound generated to the vehicle bodywork is prevented, or transmission occurs only in a greatly attenuated form, in a simple and costeffective manner.

According to one aspect of the invention there is provided a control device comprising a housing containing a printed circuit board on which is mounted at least one structure-borne sound generating electrical component, at least one electrical external plug connection mounted on the housing being mechanically and electrically connected to the printed circuit board, a resilient damping ring connecting the plug connection to the housing and the printed circuit board bearing against the housing through at least one resilient damping element.

More particularly, the invention can provide a control device comprising a housing with an end plate closure, at least one electrical plug connection in the end plate having electrical plug components arranged in an insulated manner in the plug connection, a printed circuit board in the housing mechanically connected to the plug components and the plug connection, and at least one structure-borne sound generating electrical component mounted on the printed circuit board, a resilient damping ring being provided between the plug connection and the end plate and the printed circuit board bearing against the housing through at least one resilient damping element.

It is advantageous to provide a resilient damping ring in the junction between the plug connection to the housing and the end plate, because this is a simple, low-cost way of effectively preventing transmission of structure-borne sound from the plug connection connected to the printed circuit board to the housing and to the end plate of the control device, as the resilient damping ring can constitute the only connection between the plug connection and the end plate and housing in the region of the end plate.

The arrangement whereby the printed circuit board bears against the housing through at least one resilient damping element has the advantage, first, that a secure attachment of the printed circuit board in the housing can be obtained, and second, that no (or only attenuated) structure-borne sound can be transmitted directly from the printed circuit board to the housing.

It is advantageous for the damping ring to have a bellows-like or finned configuration as it will then have, even in the compressed fitted condition, only a small area of contact with the housing and/or end plate and/or plug connection, so that the transmission of structure-borne sound is even more effectively damped.

Moreover if the damping ring is greatly compressed in the fitted condition the bellows-like or finned configuration limits transmission of structure-borne sound to the casing due to the compacting of the material.

The location of the damping ring on a surrounding rim of the plug connection can give in a particularly simple, low-cost design and manufacture, combined with a secure, stable mounting of the damping ring on the plug connection both before and during assembly.

It is advantageous for the, or at least one, damping element to have an angled configuration and for at least one U-shaped seat element for the, or at least one, damping element to be arranged on an inside end of the housing opposite the end plate, both because this feature achieves its purpose in a particularly simple and lowcost manner from the point of view of design and manufacture, and because owing to the angular configuration of the damping element in conjunction with the U-shaped configuration of the seat element, upon assembly of the control device, that is to say, in particular when the printed circuit board is inserted into the housing, correct positioning of the printed circuit board with the, or at least one, damping element with respect to the, or at least one, seat element is automatically obtained, thus also ensuring that optimum damping for the transmission of structure-borne sound is assured.

An embodiment of a control device according to the invention, given by way of example, is illustrated in the accompanying drawings and will now be described in detail with reference to those drawings, in which: Fig. 1 shows a section through a control device for motor vehicles according to the invention, Fig. 2 shows detail X of Fig. 1 to a larger scale, Fig. 3 shows detail Y of Fig. 1 to a larger scale.

Fig. 1 shows a section through a control device for a motor vehicle comprising a housing or casing (G).

An end plate (S) which can for example be snap fastened onto the casing (G) forms a closure for the casing (G). A plug connection (A), in which electrical plug components (T) are arranged so as to be insulated from each other, is fitted into the end plate (S).

The electrical plug component (T) are electrically connected to a printed circuit board (L) arranged in the casing (G). The printed circuit board is also mechanically connected to the plug connection (A) to form a fixed attachment. Electrical conductor lines and electrical and/or electronic components (B) are arranged on the printed circuit board. At least one electrical component (B) generates structure-borne sound when operated. In Fig. 1 this electrical component (B) takes the form of an electromagnetic relay which generates sound as a result of the switching of the relay contacts when it is operated.

To prevent transmission of the structure-borne sound generated by the electrical component (B), an elastomeric damping ring (R) is arranged, as the sole connecting element, in the joint between the plug connection (A) to the casing (G) and the end plate (S), being mounted on a peripheral rim of the plug connection.

In this way, the plug connection (A) is fitted to the end plate (S) in such a way that it has no contact with the end plate (S).

For correct location of the printed circuit board (L) in the casing (G) and to prevent transmission therebetween of structure-borne sound the printed circuit board (L) bears against the casing (G) through one or more elastomeric damping elements (E). The, or at least one, damping element (E) has an angled configuration and mates with one, or at least one, U-shaped seat element (F) located on the inside end wall of the casing (G) opposite the end plate (S). The angular configuration of the damping element or elements (E) and the U-shaped configuration of the seat element or elements (F) results in simple and reliable self-positioning of the printed circuit board (L) in the casing (G) on insertion of the printed circuit board (L) into the casing (G), which moreover ensures correct location of the damping element or elements (E), thus providing effective damping of the structure-borne sound at all times.

In the example embodiment shown here, for easy assembly and positionally secure fitting of the damping ring (R), the plug connection (A) is provided with a surrounding rim (K) on which the damping ring (R) is mounted. To allow simple and low-cost manufacture, both the casing (G) and the end plate (S), and also the plug connection (A), can be made of plastic. The seat element or elements (F) can, as shown in the drawings, be made integral with the casing (G).

In detail X of Fig. 2 there is shown, by way of example, the end plate (S) connected to the casing (G) of the control device by a snap-locking connection (V). The elastomeric damping ring (R) bears both against the casing (G), which is stepped in the bearing area, and against the end plate. For particularly effective damping of the structure-borne sound, the damping ring (R) in its interface with the casing (G) has a bellows-like or finned configuration to reduce the bearing area. This is formed, for example, by circumferential grooves (I) in the outer surface of the damping ring (R). The bellows-like or finned configuration of the damping ring may, in other possible embodiments, also be directed towards the interface with the end plate (S) and/or plug connection (A).

Fig. 3 shows detail Y of Fig. 1. Here, the casing (G) has a seat element (F) for the, or at least one, damping element (E), which is U-shaped and in this case (as an example) forms part of the casing (G). The damping element (E) has an angular configuration which is adapted both to the thickness of the printed circuit board (L) and to the width of the U-shaped seat element (F).

The damping element (E) may be made of a foamed plastic material with good damping properties. The damping element or elements (E) can be permanently joined to the printed circuit board (L) or to the U-shaped seat element (F) prior to assembly of the control device. The, or at least one, seat element (F) can be provided as a U-shaped groove in the inside end wall of the casing (G) opposite the end plate (S).

Claims

1. Control device comprising a housing containing a printed circuit board on which is mounted at least one structure-borne sound generating electrical component, at least one electrical external plug connection mounted on the housing being mechanically and electrically connected to the printed circuit board, a resilient damping ring connecting the plug connection to the housing and the printed circuit board bearing against the housing through at least one resilient damping element.

2. Control device comprising a housing with an end plate closure, at least one electrical plug connection in the end plate having electrical plug components arranged in an insulated manner in the plug connection, a printed circuit board in the housing mechanically connected to the plug components and the plug connection, and at least one structure-borne sound generating electrical component mounted on the printed circuit board, a resilient damping ring being provided between the plug connection and the end plate and the printed circuit board bearing against the housing through at least one resilient damping element.

3. Control device according to claim 1 or claim 2, wherein the damping ring has a bellows-like or ribbed configuration.

4. Control device according to any one of claims 1 to 3, wherein the damping ring is mounted on a peripheral rim of the plug connection.

5. Control device according to any one of the preceding claims, wherein the or at least one damping element has an angled configuration and in that at least one U-shaped seat element for said damping element or elements is arranged on an end wall of the housing.

6. Control device constructed and arranged for use substantially as described herein with reference to the accompanying drawings.