DE19854377A1 - Manufacturing method for a plunger-guided armature of an actuator for lift valves of an internal combustion engine - Google Patents

Abstract

In a manufacturing method for a tappet-guided armature of an actuator for lift valves of an internal combustion engine, a ceramic tappet with a specially designed armature made of a soft magnetic iron material is connected essentially non-positively via longitudinally divided cone pieces, the cone pieces positioned via a circumferential groove in the ceramic tappet being pressed into a press Seat connection are brought with the anchor, which is additionally secured in position by means of a material or form-fitting training on the cone pieces.

Description

According to the preamble of claim 1, the invention relates to Manufacturing process for a plunger-guided armature of an actuator for globe valves an internal combustion engine, in which a plunger with a specially designed Anchor made of a soft magnetic iron material is connected to the drive.

A known drive-resistant connection of the armature to the shaft is an example achieved by soldering, as this is the schematic representation of the drawing the patent application 197 55 271 can be found.

This connection method is disadvantageously complex and requires for example, because of the compliance with the soldering gap, an expensive holding device device for positioning anchor and shaft in relation to each other. It continues relatively high soldering temperature to make it from a soft magnetic iron material designed anchor loses its magnetic properties, which in a complex heating process must be restored. Loses in this heat process the plunger made of an iron material is one with regard to wear resistance unfavorable structural transformation. Finally, due to the relative long heat exposure the disadvantage of warping both components  Oblique or by bending the components, where appropriate, another Post-processing of the anchor may be necessary.

In the known arrangement, the plunger is made of an iron material, which disadvantageously results in a relatively high mass or a large mass inertia and also the plunger magne made of an iron material table causes interference.

The invention has for its object a manufacturing method for a mass show reduced tappet-anchor unit.

This object is achieved with patent claim 1, the plunger consisting of one Ceramic material is manufactured with at least one guide section and with a circumferential groove axially spaced from the guide section for positioning is formed longitudinally tapered pieces, being positioned on the tappet Cone pieces arranged a finished machined anchor with a press fit and additionally at least with the tapered sections of the cone pieces or cohesively connected by electron beam welding.

With the invention, a method suitable for series production is advantageously achieved with additional positive locking of the anchor on the wedge pieces without Heat input is feasible and thus the anchor is neither a delay nor is subject to a loss of maximum soft magnetic properties. The before Advantages mentioned are also given if additional security of the Anchor with the cone pieces of this by means of electron beam welding with them is connected because the associated heat input with the corresponding Control of electron beam welding is minimal.

The basic idea of the invention is the anchor on the cone located on the shaft pieces so that the cones are designed for self-locking radial clamping of the tapered pieces on the ceramic shaft is, which is advantageously so high that the entire spring and magnet  resulting forces are transferred non-positively, the Circumferential groove only serves to position the cone pieces.

The proposed additional material or positive Ver Binding the anchor to the cone pieces serves to loosen the anchor counteract by the acting alternating forces.

With the invention is in a further advantageous manner a lower weight Tappet-anchor unit or a lower moving mass achieved so that the spring Forces of the spring-mass system can be reduced and so can the Magnetic surface of each actuator, which advantageously reduces weight and installation space are. Furthermore, there is minimal skewing with the manufacturing method according to the invention stood between anchor and plunger, the magnetic egg properties of the anchor are fully preserved and by the plunger from a Kera The mic material eliminates magnetic interference fields. After all, it is a reliable process Connection achieved at low manufacturing costs, especially when in wide rer embodiment of the invention of the plunger made of silicon nitride ceramic and machined to finished size is fed to the manufacturing process.

Further configurations are the content of the subclaims.

The invention is based on a plunger-anchor unit shown in the drawing explained.

In a manufacturing method for a plunger-guided armature 1 of an actuator, not shown, for lift valves of an internal combustion engine, not shown, a plunger 2 is connected in a drive-proof manner to a separately designed armature 1 made of a soft magnetic iron material.

In the manufacturing method for a reduced-mass tappet-anchor unit, which is improved according to the invention, it is assumed that a tappet 2 made of a ceramic material has at least one guide section 3 . Further, the plunger 2 is formed with an axially spaced apart from the guide portions 3 circumferential groove 4 for positioning longitudinally split cotters. 5 These tapered pieces 5 positioned on the tappet 2 serve to arrange the finished machined anchor 1 with a press fit. Thus, the armature 1 is pressed onto the attached arrange on the plunger 2 th cotters 5 so that a radial clamping is reached, the cone pieces on the ceramic plunger 2 via the designed for self-locking conical surfaces, which is so high that the of spring and magnetic forces resulting operating forces are transmitted non-positively, the circumferential groove 4 is used only for positioning the cone pieces 5 .

In order to avoid a loosening of the press-fit connection between the cone pieces and the armature 1 due to the alternating application of force, the armature 1 is at least with the tapered sections 6 of the cone pieces 5 additionally Lich either positively or cohesively connected by electron beam welding. The securing of the armature 1 to the cone pieces 5 can be further increased in that the cone pieces 5 are connected at both ends to the armature 1 in a material or form-fitting manner.

In an embodiment of the invention it is further proposed that the plunger 2 is made of silicon nitride ceramic with the advantage that this plunger 2 can be fed to the manufacturing process finished to finished dimensions.

The anchor 1 used in the manufacturing process according to the invention is either made from pure iron or from a nickel-iron compound (NiFe) or from a silicon-iron compound (SiFe) or from a cobalt-iron compound (CoFe), wherein the armature 1 further finished to its shape and heat treated with respect to optical magnetic properties, the manufacturing method according to the invention is supplied.

According to a further proposal for the manufacturing method according to the invention, it is provided that the two taper pieces 5 used for each ceramic tappet 2 are made as extruded parts from a low-alloy carbon steel with C ≦ 0.4%, which is deformable by upsetting / stamping or suitable for electron beam welding.

In order to obtain a production method without any particular for the armature 1 adverse heat input the bevel pieces are 5 compresses ge at their respective projecting over the anchor 1 sections 6 and 6 to the position-securing anchor 1 or provided with squeezed spreading shaped projections (not ge shows ).

In order to have a non-hazardous, lowest possible heat input when the armature 1 is connected to the cone pieces 5 in a cohesive manner, the armature 1 is welded to the cone pieces 5 by means of an electron beam.

With the manufacturing method according to the invention a reliable, reproducible connection of the armature made of a soft magnetic iron material with a ceramic plunger 2 is achieved at relatively low manufacturing costs, the Kera mic-plunger 2 machined to finished dimensions with finished sections 3 the manufacturing process is supplied.

Claims (5)

1. Manufacturing method for a tappet-guided armature of an actuator for lifting valves of an internal combustion engine,

• in which a plunger ( 2 ) is connected in a drive-proof manner to a separately designed armature ( 1 ) made of a soft magnetic iron material, characterized in that
• - That the plunger ( 2 ) is made of a ceramic material with at least one guide section ( 3 ), and
• - With a from the guide section ( 3 ) axially spaced circumferential groove ( 4 ) for positioning longitudinally divided cone pieces ( 5 ) is formed, wherein
• - On the tappet ( 2 ) positioned cone pieces ( 5 ) a finished machined anchor ( 1 ) with a press fit and at least with the tapered sections ( 6 ) of the cone pieces ( 5 ) is additionally positively or cohesively connected by electron beam welding.

2. Manufacturing process according to claim 1, characterized in that the plunger ( 2 ) made of silicon nitride ceramic and finished to the finished process is fed to the manufacturing process. 3. Manufacturing method according to claim 1 and 2, characterized in that the armature ( 1 ) made of pure iron or NiFe or SiFe or CoFe, finished to shape and treated with regard to magnetic properties is supplied to the manufacturing process. 4. Manufacturing method according to one of claims 1 to 3, characterized in that the tappet ( 2 ) used two cone pieces ( 5 ) as extruded parts from a deformable by upsetting / stamping or for electron beam welding (arrow "A") suitable low-alloy carbon steel with C ≦ 0.4%. 5. Manufacturing method according to claims 1 to 4, characterized in that the conical pieces ( 5 ) at both ends ( 6 , 6 ') with the anchor ( 1 ) are integrally or positively connected.