Patent Application
20070149035
The present invention relates to an electrical connection assembly. More particularly, the present invention relates to an electrical connection between a cylindrical high current contact socket or a high current contact pin and a planar printed conductor element.
At present, mainly press-fit techniques are used to link high current contact sockets or high current contact pins to boards. In press-fit connections, the high current contact socket is inserted into an undersized hole made in the board. Compared to conventional contact sockets and contact pins, contact sockets and pins suitable for high current applications, e.g. current higher than 100 A, have relatively greater diameters. Because of their greater diameters, high current contact sockets and pins often induce stress in the board where they are inserted, thereby deforming the board. That is especially a problem in the automotive domain, where material thickness often fluctuate due to temperature changes. In practice, that often leads to crack formations in the board and possibly detachment of electrical contacts. Moreover, another disadvantage is that contact surface between the contact socket or pin and the board are small. More specifically, the contact surface is where the contact sockets or contact pins are electrically connected to the board, and only a narrow region is provided where the side of the contact socket or pin contacts the edge of the board opening that receives the contact socket or pin.
Accordingly, an object of the invention is to provide an improved connection between a high current conductor and a planar printed conductor element. In one embodiment of the invention, an electrical connection assembly is provided. The electrical connection assembly has a printed conductor element with a first surface and a second surface, a high current conductor, a first contact element, and a second contact element. The conductor element has an opening that extends from the first surface to the second surface. The high current conductor is received in the opening and extends substantially perpendicular to the first and second surface. The first contact element is coupled to an end of the high current conductor and placed adjacent to the first surface. The second contact element is coupled to an opposite end of the high current conductor and placed adjacent to the second surface so that the printed conductor is clamped between first and second contact elements.
In accordance with another embodiment of the invention, a method for forming the electrical connection includes the steps of first coupling a first contact element to the high current conductor. The next step is inserting the high current conductor into an opening of the printed conductor element. Then a second contact element is coupled to the high current conductor. Finally, the printed conductor element is clamped between the first and second contact elements thereby forming an electrical coupling.
Other objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Referring to
The high current conductor 5 can be a high current contact socket, a high current contact pin, or other similar current conductors. In the preferred embodiment and in
In another embodiment of the invention, one of the contact elements 13 or 14 is made integral with the high current conductor 5. In particular, the contact element 13 or 14 shaped similar to a nail head is located on one end of the high current conductor 5 so that the high current conductor 5 can be inserted into the opening 12 of the printed conductor element 7 until the contact element 13 or 14 prevents further insertion because the size of the contact element 13 or 14 will not pass through the opening 12 of the printed conductor element 7.
The printed conductor element 2 has a first surface 3 and a second surface 4 opposite to the first surface 3. The printed conductor element 2 can be a board or a pressed screen. The printed conductor element 2 has an opening 12 that extends from the first surface 3 to the second surface 4. Printed conductors 7 may be provided on at least one surface 3 or 4 of the printed conductor element 2.
The high current conductor 5 is inserted into opening 12 of the printed conductor element 2 so that a portion of the high current conductor 5 extends substantially perpendicular to the first surface 2 and the second surface 4. Opening 12 may be sized larger than the largest diameter of the high current conductor 5. The high current conductor 5 and printed conductor element 2 are coupled mechanically and electrically by the two contact elements 13 and 14. The contact element 13 couples the high current conductor 5 to the first surface 3 of the printed conductor element 2, and the contact element 14 couples the high current conductor 5 to the opposite second surface 4. Each contact element 13 and 14 has an annular shape providing a contact opening 15 (
In another embodiment, only one contact element 13 or 14 may be used where the one contact element 13 or 14 makes contact with the printed conductor 7. In an embodiment where the outer sleeve 6 of conductor 5 is made of plastic, an electrically conductive connection between one of the contact elements 13 or 14 and the tubular part 8 of conductor 5 is provided.
The contact elements 13 and 14 clamp the printed conductor element 2 in the axial direction and hold the high current conductor 5 inmmovably. Pressing the contact elements 13 and 14 toward the printed conductor element 2 while fixing the contact elements 13 and 14 in position provides a clamping contact. Thus, it is not possible to rotate the contact elements 13 and 14 together with the high current conductor 5 around its longitudinal axis.
By contact elements 13 and 14 holding the high current conductor 5 in the oversized opening 12, the electrical connection assembly has the advantage of preventing warping of the printed conductor element 2. The printed conductor element 2 is exposed to a clamping force only in the axial direction from the two contact elements 13 and 14, each of which concurrently come into contact with opposing surfaces 3 and 4 of the printed conductor element 2.
When at least one contact element 13 or 14 receives the high current conductor 5, the connecting forces are distributed uniformly between the high current conductor 5 and the printed conductor element 2 because the contact elements 13 and 14 encircle the high current conductor 5. Contact elements 13 and 14 preferably encircle the high current conductor 5 annularly. In particular, the contact element 13 or 14 is rotationally symmetrical with respect to the longitudinal axis of the high current conductor 5.
The contact element 13 or 14 can be coupled to the high current conductor 5 by several different techniques. At least one of the contact elements 13 or 14 can be coupled to the high current conductor 5 by press fit. By press fitting the contact element, additional fastening mechanisms, such as soldering, are avoided. Another simple, secure and effective way of coupling at least one contact element 13 or 14 to the high current conductor 5 is crimping. A crimping tool is applied to the outer radial surface of the contact element 13 or 14 after the high current conductor 5 is disposed within the contact element 13 or 14. Then, the crimping tool compresses the contact element 13 or 14 so that the contact element 13 or 14 permanently clamps to the high current conductor 5. After crimping the contact element 13 or 14, a force acting radially inward is provided. Similar to press fitting, the need for additional fastening mechanisms, such as soldering, is eliminated.
Another advantage is that connecting forces are distributed uniformly between the high current conductor and the printed conductor element, when at least one contact element is coupled to the high current conductor.
Optimum contact between the contact element 13 or 14 and the printed conductor element 2 is achieved when at least one contact element 13 or 14 makes contact with at least one printed conductor 7. Preferably, the printed conductors 7 are disposed on both surfaces 3 and 4 of the printed conductor element 2. In this embodiment the two contact elements 13 and 14 provide the electrical and mechanical contact. The contact surface is larger than conventional connection methods so that the electrical contact resistance is minimized allowing a large amount of current to flow without excessive heating of the contact points. When at least one contact element 13 or 14 establishes an electrically conductive connection between the high current conductor 5 and the printed conductor element 2, the electrically conductive connection is not susceptible to mechanical loads and temperature fluctuations. The printed conductor 7 can be provided in the region where the contact element 13 or 14 comes into contact with the high current conductor 5, such as a printed conductor eye that peripherally surrounds the high current conductor 5.
Referring to
The annular contact section 17 extends in the radial direction and has a gripping surface 18 which is provided as a ridged rim 21. A retaining section 19 runs in the axial direction with the contact opening 15 within which the high current conductor 5 is disposed. The gripping surface 18 enlarges the contact surface between the printed conductor 7 and the contact element 13. The gripping surface 18 may also penetrate a possible oxide layer on the printed conductor 7 which can be provided in the contact area as a printed conductor eye.
Preferably, the contact side 17 of the contact element 13 facing the surface of the printed conductor element 2 has the gripping surface 18 for increasing the contact surface and/or for penetrating an oxide layer. The gripping surface 18 may penetrate any oxide layer located on the top of the printed conductor 7, which in turn minimizes contact resistance. The gripping surface 18 on the contact side 17 can be a ridged rim provided on its periphery where the ridge tips 22 thereof are placed adjacent to the surface of the printed conductor element 2. The tips would then penetrate any oxide layer on the printed conductor 7.
An extremely resilient connection between the high current conductor 5 and the printed conductor element 2 is obtained when at least one contact element 13 or 14 is made elastic in the axial direction. A permanent clamping force between the contact element 13 or 14 and the high current conductor 5 is provided by an induced spring force.
FIGS. 3 to 5 schematically show steps in a connecting method as claimed in the invention. The method has the advantage of avoiding surface warping of the printed conductor element 2. According to the method, a high current conductor, shown as a high current contact pin 20 in FIGS. 3 to 5, with first contact element 13 attached to it or formed integrally is inserted into the opening 12 of the printed conductor element 2 until the contact element 13 adjoins the first surface 3 of the printed conductor element 2. In
Then, a second contact element 14 receives the high current conductor 5 and is fixed on the second surface 4 of the printed conductor element 2 opposite the first contact element 13.
The second contact element 14 must come into contact with the printed conductor element 2 so that the printed conductor element 2 is clamped between the two contact elements 13 and 14. The second contact element 14 is pressed against the printed conductor element 2 with an axial pressing force. Simultaneously, it is exposed to a radial force. The radial force compresses the second contact element 14 so that it is crimped thereby clamping it to the high current contact pin 20. When the second contact element 14 is coupled to the high current contact pin 20, a clamping connection is formed where the high current contact pin 20 is coupled to the printed conductor element 2.
In
The electrical coupling is provided by at least one of the contact elements 13 or 14. If one of the contact elements 13 or 14 is made of an electrically conductive metal, then the contact element 13 or 14 forms an electrical coupling by providing an electrical pathway between the high current conductor and printed conductor element 2, preferably through the printed conductor 7. One of the contact elements 13 or 14 may also be made elastic to provide a more resilient coupling. Also, one of the contact elements 13 or 14 may be provided with the gripping surface 18 to increase the contact area and/or to penetrate a possible oxide layer on the printed conductor 7.
While particular embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 062 709.9 | Dec 2005 | DE | national |
