Inductor devices – Core – Laminated type
Patent
1993-12-09
1995-03-14
Kozma, Thomas J.
Inductor devices
Core
Laminated type
310216, 439 92, 439431, H01F 2724
Patent
active
053980140
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a core having earth contacting.
More particularly, it relates to a coil having an iron core, in particular an ignition coil consisting of a primary and secondary winding which are inductively coupled by an iron core.
Such an iron core normally consists of a multiplicity of individual thin laminations which are, for example, punched, insulated by varnishing and subsequently packed one above another to form a core stack. During stacking, the individual laminations are, for example, riveted or welded to one another, so that the laminations are electrically interconnected. These core stacks are electrically connected to earth potential, which hitherto has been performed by means of a screw and toothed disc when mounting the core stack on a holder. However, effective earth contacting is not always provided in this operation, for example because of inadequate removal of insulating varnish.
Another possibility is to press a metallic sleeve into recesses or holes in the core stack. During this pressing-in process, the insulating layer at the points of contact--inner wall of the bores of the core stack and outer wall of the sleeve--is at least partially removed, thus producing the possibility of earth contacting by means of this sleeve. The core stack is mounted on a holder by screwing the sleeve, thus simultaneously producing a conductive earth connection. This earth contacting uses a relatively large quantity of material and requires a plurality of steps in the production. This method of earth contacting is not economic enough on the way to an ever more cost effective production.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a core of the above mentioned type, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a core having earth contacting to a holder via a connecting element and by means of removing the insulating layer in the region of the mounting bores, wherein in accordance with the present invention, at least one lamination of the core stack is provided at the mounting bore with a projection producing the earth contact with the connecting element to be inserted into the mounting bore.
When the core is designed in accordance with the present invention, it has, by contrast, the advantage that the earth contacting between the core stack and holder is produced directly via a screw or the like, so that it is possible to dispense with the toothed disc or sleeve. The fact that the step of "pressing in the sleeve" is also saved is to be viewed as a further advantage.
It is especially advantageous that it is necessary to punch out from only one lamination a relatively small area at the later mounting point before the stacking. It is irrelevant in this case what form the punched area has. Care need only be taken to ensure that the thread of the screw is not damaged by the proud material when mounting. The seating of this correspondingly punched lamination in the core stack is likewise irrelevant.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the plan view of a core stack,
FIG. 2 the side view of the core stack from FIG. 1, with the mounting screw represented,
FIG. 3 a plan view of a second core stack, and
FIG. 4 the side view of the core stack from FIG. 3, with mounting screw.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 are to be explained together, since they show the same object only from different views. To be seen in both drawings is the cor
REFERENCES:
patent: 1727219 (1929-09-01), Scharf et al.
patent: 2135937 (1938-11-01), Gordon
Betz Dieter
Herrmann Reinhold
Stegmaier Friedrich
Kozma Thomas J.
Robert & Bosch GmbH
Striker Michael J.
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