DE102005040364A1 - Bar coil for ignition systems - Google Patents

Abstract

The invention relates to a rod coil for ignition systems, in particular for ignition systems in internal combustion engines, comprising a rod core (2), a first coil former (3) with a first coil winding (4), which are arranged around the rod core (2), and a second coil former with a second coil winding, which are arranged around the first coil former (3) with the first coil winding (4), a gap (8) between the rod core (2) and the first coil former (3) being filled with a liquid medium (5) is.

Description

The The invention relates to a rod coil for ignition systems, which in particular as ignition coil used in internal combustion engines of motor vehicles.

rod coils for ignition systems are of the prior art in different configurations known. Known bar coils are constructed such that in one casing in a central position a rod-shaped, ferromagnetic core of an open magnetic circuit is arranged. The core is surrounded by a first bobbin with a first coil winding (Secondary winding). With a predetermined radial distance from the secondary winding Further, a second bobbin arranged with a second coil winding (primary winding). Between the rod core and the first bobbin, for example, a Layer of epoxy resin arranged, which consists of a cured, electrically insulating casting resin is formed. The rod core is thus formed from an electrical sheet, which usually is covered with a molding material, and the second bobbin is usually made of a plastic.

There the individual components of the bar coil made of different materials are made, these have different thermal expansion coefficients on. From there you can in operation due to the occurring temperature fluctuations voltages and subsequently cracks in the cured Cast resin arise, which can lead to failure of the rod coil.

Advantages of invention

The Bar coil according to the invention for ignition systems with the features of claim 1, in contrast, the Advantage on that they have an improved thermo-mechanical decoupling allows without the risk of cracks in the molding material (secondary bobbin) between the rod core and the secondary winding occurs. Furthermore, according to the invention no punctual mechanical occur Voltage overshoots between the rod core and the secondary coil body. This is inventively characterized achieved that a gap between the rod core and the secondary coil body with a liquid Medium filled is. By using the liquid can further reduces a gap between the rod core and the secondary coil body Be there the liquid also penetrates into small column. The space between the rod core and the secondary coil body can completely or partially with liquid filled be.

The under claims show preferred developments of the invention.

Preferably is the space between the rod core and the secondary coil body completely with the liquid Medium filled.

Especially preferred is the liquid Medium viscous, causing in operation also vibrations or similar at least partially absorbed.

Further preferred is the liquid Medium electrically insulating. As a result, the liquid medium takes over additionally still an isolation function.

When liquid Medium is preferably a non-hardening epoxy or an oil, in particular transformer oil on synthetic or mineral base.

Around an outflow of the liquid Prevent medium, the secondary coil body is preferably formed cup-shaped. The secondary coil body can in one piece be formed or as a sleeve with a lower bottom.

Further is preferred on the secondary coil body a upper cover provided to the core at its upper end cover. This will prevent liquid medium from the gap exits between the rod core and the secondary coil body.

drawing

following will be an embodiment with reference to the accompanying drawings the invention described in detail. In the drawing is:

1 a schematic sectional view of a portion of a rod coil according to an embodiment of the present invention and

2 an enlarged partial view of 1 ,

description of the embodiment

following With reference to the figures, an embodiment of the invention described in detail.

1 shows the schematic structure of a Bar coil according to the invention 1 , The bar coil 1 includes a rod core 2 , which consists of a magnetizable material, such as electrical sheet or similar. is made. Around the bar core 2 is with a little distance a first bobbin (secondary bobbin) 3 arranged, which is cylindrical about the rod core 2 is formed around. On the secondary bobbin 3 is a serving as a secondary coil winding 4 arranged. This winding 4 communicates with a high voltage terminal, not shown, which is electrically connectable to the spark plug. Furthermore, the bar coil comprises 1 a primary coil body, not shown, which carries a secondary winding designed as a primary winding. The primary winding is connected to a low voltage source. The primary coil body with associated primary winding is for clarity in 1 not shown, however, is arranged around the secondary spool in a known manner.

How out 1 can be seen, comprises the secondary body 3 a floor area 3a so that the secondary body 3 down in the area of a contact 7a a Entstörkontaktierbereichs 7 is completed. The secondary body 3 is formed in one piece and preferably made of a plastic. Like from the 1 and 2 is apparent, is between the secondary coil body 3 and the rod core 2 a gap 8th provided, which with a liquid medium 5 , such as an oil, is filled. How out 1 is apparent, is the gap 8th formed ring-shaped and the entire space between the rod core 2 and the secondary coil body 3 is with liquid medium 5 filled.

At the upper end of the bar coil is a cover 6 provided, which the gap 8th between the rod body 2 and the secondary coil body 3 bounded to the top and sealed.

Thus, according to the invention, the rod core 2 in a liquid medium 5 embedded. The liquid medium 5 is ideally an electrically insulating liquid.

By providing the embedding of the rod core 2 in a liquid medium is an excellent thermo-mechanical decoupling between the individual components of the bar coil 1 possible. This can prevent cracks or other damage to the components due to thermal stresses during operation. Furthermore, it is prevented that punctual mechanical voltage increases occur because the liquid medium 5 throughout the gap 8th between the secondary coil body 3 and the rod core 2 provides a same pressure. Since the liquid medium can penetrate even the smallest column, the gap 8th between the rod core 2 and the secondary coil body 3 be chosen very small. This additionally saves space in the radial direction of the bar coil 1 reached.

Thus, the rod coil according to the invention 1 Ensure that it has a long service life even under extreme operating conditions due to its thermal decoupling. The liquid medium 5 It also provides an excellent temperature balance between the individual components due to its liquid properties.

Claims (9)

Rod coil for ignition systems, in particular for ignition systems in internal combustion engines, comprising a rod core ( 2 ), a first bobbin ( 3 ) with a first coil winding ( 4 ) around the rod core ( 2 ) are arranged around, and a second bobbin with a second coil winding, which around the first bobbin ( 3 ) with first coil winding ( 4 ) are arranged around, wherein a gap ( 8th ) between the rod core ( 2 ) and the first bobbin ( 3 ) with a liquid medium ( 5 ) is filled. Rod coil according to claim 1, characterized in that the gap over the entire axial length of the rod coil completely with liquid medium ( 5 ) is filled. Bar coil according to one of the preceding claims, characterized in that the liquid medium ( 5 ) is viscous. Bar coil according to one of the preceding claims, characterized in that the liquid medium ( 5 ) is electrically insulating. Bar coil according to one of the preceding claims, characterized in that the liquid medium ( 5 ) is a non-hardening epoxy or an oil, in particular a synthetic or mineral based transformer oil. Rod coil according to one of the preceding claims, characterized in that the first bobbin ( 3 ) is cup-shaped. Rod coil according to claim 6, characterized in that the cup-shaped first bobbin ( 3 ) is integrally formed. Bar coil according to one of the preceding claims, characterized by a cover element ( 6 ) to the space between the rod core ( 2 ) and the first bobbin ( 3 ) at the open Cover area of the cup-shaped bobbin. Rod coil according to claim 8, characterized in that the cover element ( 6 ) simultaneously acts as a sealing element.