The invention relates to a pre-installation assembly for a contact arrangement of a sensor assembly as generically defined by the preamble to independent claim 1.
In German Published Patent Disclosure DE 19917941 A1, a braking device for a vehicle brake system with a contact arrangement for a sensor assembly is disclosed. In the braking device described, the control electronics, to simplify installation, are accommodated in a housing inverted over at least one pressure sensor, and the electrical connection between the pressure sensor and the control electronics is made automatically upon installation via four spring contact pins. In the process, the housing is secured to a hydraulic block of the braking device, into which block at least one pressure sensor is inserted, so that the spring contact pins are braced on their ends with a defined contact pressure between the facing contact faces of the pressure sensor and of the control electronics. The spring contact pins are inserted into guides which are located in an insulation piece, and the spring contact pins each have a contact sleeve with a contact spring located in it and at least one contact tappet axially displaceable in the contact sleeve, which tappet is acted upon by the contact spring, embodied as a compression spring, in the expulsion direction out of the guide sleeve. Between the contact sleeve and the contact tappet, an axial brace is provided, by which the contact tappet is kept in its contact sleeve. This brace comprises a crimped-over peripheral zone on the end of the contact sleeve that a pistonlike thickened portion of the graduatedly offset contact tappet runs up against. In some embodiments of the known spring contact pins, both end regions are formed by a contact tappet, and from opposite directions the contact tappets engage their contact sleeve that forms the middle region of the spring contact pin. Between the thickened ends of the two contact tappets, the helical compression spring guided in the contact sleeve is braced and, when the spring contact pin has not yet been built in, presses the contact tappet into its terminal position in which it is maximally expelled from the contact sleeve. Thus even in the not yet built-in state, the spring contact pin comprising the contact sleeve, contact tappets and contact spring, forms a stably preassembled and thus easily manipulated assembly. The components of the spring contact pin, however, must be manufactured with extreme dimensional stability, to enable ensuring durable, problem-free contact-making. This is especially true when the assembly overall is designed in filigree fashion. As a result, producing the pre-installation assembly comprising the contact sleeve, contact spring and contact tappets is technically complicated as a whole, and even the individual spring contact pin comprising precision components is relatively expensive.
From German Patent Disclosure DE 10244760 A1, a contact arrangement in a pressure sensor assembly is also known, for monitoring pressure in a vehicle brake system. In this arrangement, spring contacts are provided, which comprise solely the spring winding of a wound helical compression spring and are therefore distinguished by a technically simple design. These helical compression springs used as spring contact pins each have two winding sections with different diameters, and the longer winding section, which penetrates guides in support components, has a markedly smaller winding diameter than a winding section that protrudes from the guides. To improve the guidance properties, the spring winding in the longer winding section is wound as a block; as a result, the axial spring load must be exerted solely by the winding section that protrudes from the guide, which to that end must be correspondingly compressed. The assembly process thus requires that outside the guide, there is enough space for supplying the component that is provided with the second contact face, so that the winding section protruding from the guide can be compressed to a suitable extent, thus providing the contact-making. The space required for compressing the winding section is not structurally available in all contact arrangements for sensor assemblies. Also, the contact face for the winding end of the shoulder winding section must be relatively large, which is again not wanted for every application, because it can have an adverse effect on the available space.
The pre-installation assembly according to the invention for a contact arrangement of a sensor assembly having the characteristics of independent claim 1 has the advantage over the prior art that a support component and a clamping component can be connected to one another in a simple way, via connection means, so that at least one spring contact pin is positioned and held in a simple way, via aligned guides, penetrated by the pin, in the support component and the clamping component. For forming the pre-installation assembly of the invention, the at least one spring contact pin is held in the guide of the support component, and a first end section of the at least one spring contact pin is axially braced in the associated guide of the support component. A second end section of the at least one spring contact pin is axially braced in the associated guide of the clamping component, and in the aligned position of the corresponding guides, the clamping component and the support component are connected to one another via the connection means. After the clamping component has been connected to the support component, the at least one spring contact pin is automatically compressed to the desired length and is kept in this position, captive, in the aligned guides of the clamping component and of the support component. As a result, advantageously, an easily manipulated pre-installation assembly for a contact arrangement of a sensor assembly is created.
By the provisions and refinements recited in the dependent claims, advantageous improvements to the pre-installation assembly for a contact arrangement of a sensor assembly recited in independent claim 1 are possible.
It is especially advantageous that the aligned guides of the support component and of the clamping component, in order to be connected to one another, can easily be put into their construction position via positioning means of the corresponding support component and clamping component. As the connection means and/or positioning means between the clamping component and the support component, at least one press-fit peg, for instance, can be provided, which in the installed state is press-fitted into an associated press-fit bore. The press-fit peg and the associated press-fit bore can be structurally adapted to one another, for instance by means of a suitable predetermined shape, in such a way that in the installed state, a positionally correct connection between the clamping component and the support component is attainable. Alternatively, as the connection means and/or positioning means between the clamping component and the support component, a plurality of press-fit pegs and/or positioning pegs can be provided, which in the installed state are press-fitted into associated press-fit bores with a suitable pattern of holes. To facilitate the press-fitting operation in view of the relatively small dimensions of the individual components, a central press-fit peg can advantageously be provided as the connection means between the clamping component and support component; in the installed state, this peg is press-fitted into an associated press-fit bore, and as a the positioning means, a plurality of positioning pegs can be provided, which during the press-fitting operation are introduced into associated positioning bores with a suitable pattern of holes. The positioning pegs, which are smaller than the press-fit pegs, therefore serve the purpose of location positioning and therefore also serve as a protection against relative rotation.
To attain favorable installation conditions for a plurality of spring contact pins, these pins can be disposed at approximately equal spacing from one another along a circular path. The clamping component receiving the spring contact pins can be embodied, requiring little material or space, as a hoodlike body with a central cup-shaped press-fit peg and a formed-on radially projecting annular collar; the guides for the associated end region of the spring contact pin are integrated as funnel-like sleeve bodies with the annular collar and protrude from a first face end, and in the installed state, the clamping component embodied as a hoodlike body, is connected to the corresponding support component via the central press-fit peg and a plurality of positioning pegs protruding from a second face end of the annular collar. The central press-fit peg and the at least one positioning peg extend in the same direction.
In a feature of the pre-installation assembly of the invention, the spring contact pin is embodied as a helical compression spring and at least predominantly comprises a spring winding, extending over the entire structural length of the helical compression spring, the winding sections of which spring winding, located in the end regions, are stiffened by inhibition of the axial mobility of their spring windings. As a result, advantageously, when the spring contact pin is embodied at least predominantly as a winding package, no sliding guide or the like, which requires the dimensionally stable cooperation of a plurality of contact elements, is necessary. Instead, the middle winding section serves as a compressible helical compression spring, while the winding sections in the pressure-reinforced end regions, although they do include spring windings, are however incompressible because of the means that inhibit the axial inward resilience, and thus are made pressure resistant. Such axially inhibiting means can for instance be sleevelike plastic spray-coatings, with which the spring windings in the end regions are each sheathed or joined together up to near their end cooperating with the contact face. As a result of the structural simplification, even the individual spring contact pin can already be made quite economically.
Especially advantageously, the spring winding of the spring contact pin can be tapered in both winding sections forming the end regions. The correspondingly tapered ends of the spring contact pin can cooperate with correspondingly smaller counterpart contact faces. Moreover, the wire end of the tapered spring winding can itself form a kind of central contact tip, which can rest on the counterpart contact face with a correspondingly higher pressure per unit of surface area. A further factor is that the reaction forces of the contact tip that act on the spring winding are introduced virtually centrally, since they are located near the central longitudinal axis. As a result, the middle winding section used as a helical compression spring is stressed to a lesser extent for flexion and therefore need not necessarily have radial bracing or guidance in this middle region when the winding sections forming the end regions of the spring winding in turn engage fitting guides.
To bring about simple axial bracing and simultaneously simple centering of the winding sections, forming the end regions, in the guide penetrated by them, the transition region of the spring contact pin can be wound conically, from its middle winding section to the winding section on the end regions that forms the tapered end region, with adaptation to a conical seat in the associated guide of the support component and clamping component, respectively. By means of a mirror-symmetrical design of the spring contact pin with respect to its central transverse axis, it can then be ensured that the spring contact pin can cooperate in both end regions with a conical seat, and as a result, the installation of the spring contact pin can be done more simply and in a way that is more secure against mistakes.
An especially simple design of the spring contact pin can be attained if the spring windings in the end regions of the spring contact pin of the invention are wound as a block for axial stiffening of these end regions. As a result, the spring contact pin can be a winding package wound in one piece of spring wire and can thus be produced economically as a mass-produced part in an optionally automated work cycle. Moreover, the radial bracing of the conical transition regions in the conical guide means can be improved by providing that the spring windings in the conical transition regions of the spring contact pin are at least predominantly, or entirely, also wound as a block. In contact-making for a sensor assembly or the like, the cost advantage is especially advantageous if the sensor assembly has a plurality of spring contact pins that are all designed structurally identically.
An advantageous embodiment of the invention is described in further detail below in conjunction with drawings. In the drawings, identical reference numerals identify associated components and elements that perform the same or analogous functions.
A contact arrangement 1 visible in
The individual spring contact pins 11 are each bent in one piece as a winding spring from spring wire that is a good conductor; the spring wire has a constant round cross section over the entire length of the spring winding. The spring winding of each of the structurally identical spring contact pins 11 is furthermore designed in principle as a helical compression spring and is made up of three longitudinal portions; only a middle winding section 11a is embodied as an axially compressible helical compression spring, because the windings in that longitudinal portion are wound extending toward one another at a suitable spacing. This middle winding section also has the greatest winding diameter, and this winding diameter is also constant. Adjoining the middle winding section 11a, the spring winding is wound as a block, and as a result there is no longer any axial spacing between the individual spring windings. Moreover, the spring winding tapers from the middle winding section 11a, with the interposition of a conical transition region, toward winding sections 11b forming the end regions of the spring contact pin 11. The winding sections 11b forming end regions each comprise a cylindrical winding package, which because of its windings resting on one another is embodied as axially pressure resistant and thus non-resilient.
Because of this non-resilient design of the winding sections 11b and because of the conical transition regions wound as a block, the spring contact pins 11 can be axially compressed only in the winding section 11a that forms the middle region.
In the pre-installation state with a correspondingly shortened spring winding, each of the spring contact pins 11 is braced axially between a conical annular end face of the guide 21 that predominantly receives it and an associated contact 32, which is located on the top side of a contact point 33 forming the upper termination of the sensor unit 30. This guide 21, recessed out of the circumferential wall of the housing capsule 20, has an inside diameter in a lower longitudinal portion that is slightly greater than the winding diameter of the winding section 11a, and in the upper longitudinal portion, it changes over, forming the conical annular end face, into a through bore of lesser diameter; the bore diameter is slightly greater than the diameter of the winding section 11b. The through bore ends at the top side of the housing capsule 20, and the winding section 11b protrudes with part of its length out of the top side of the housing capsule 20. Between the contact plate 33 and the guide 21, the winding section 11b of each of the spring contact pins 11 penetrates a respective associated guide 22, which is recessed out of an annular collar 28 of a clamping component 23 embodied as a hoodlike body. This clamping component 23, likewise made from insulating plastic, is joined to the housing capsule 20 via a central cup-shaped press-fit peg 26 and a plurality of positioning pegs 24 of cylindrical basic shape that protrude from an upper face end of the annular collar 28. Preferably, the press-fit pegs 26 and the positioning pegs 24 are integrally injected onto the annular collar 28 and are thus embodied in one piece with it.
As can be seen clearly in conjunction with
Once the clamping component 23, embodied as a hoodlike body, has reached its terminal position shown in
In
Number | Date | Country | Kind |
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102008040180.3 | Jul 2008 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP09/58349 | 7/2/2009 | WO | 00 | 1/4/2011 |