JPS6117784A - Electromagnetically operable valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The invention comprises a valve casing, a core made of ferromagnetic material and an armature for operating a valve part cooperating with a stationary valve seat. The present invention relates to an electromagnetically operable valve, in particular a fuel injection valve for a fuel injection system of an internal combustion engine, whose armature is engaged in such a way that the armature is drawn towards a stop surface in the energized state of a magnetic coil.

2. Description of the Prior Art Electromagnetically operable valves are already known in which the residual gap between the valve and the mover is formed by a chromium layer or a non-magnetic layer which is chemically provided.

Problem to be Solved by the Invention The disadvantage of this layer is that it has large thickness tolerances due to the manufacturing method, which results in non-uniform opening times of the valve.

Means for Solving the Problems In the configuration of the present invention, a polyimide root is arranged on the strut joint surface.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawing, a valve according to the invention is illustrated as an injection valve for a fuel injection device, which is used, for example, to compress a mixture and inject fuel into the intake pipe of an internal combustion engine, which is externally converted. In this case, the valve housing 1 is produced by a non-machining process, for example by deep drawing, rolling or similar processes. A fuel tube sleeve formed as a connecting piece is tightly fitted into the valve housing 1, which fuel tube sleeve is made of ferromagnetic material and at the same time serves as the inner core of the electromagnetically operated valve. It will be done. One end of the fuel tube, which extends concentrically with respect to the valve axis, has an inner hole 6 into which an adjusting sleeve 7 having a through hole 8 is press-fitted. The end of the fuel tube protruding from the valve casing 1 is connected to a fuel source, for example a fuel distribution conduit.

The other end of one of the fuel tubes protrudes into the interior space 9 of the valve housing and carries an insulating support 11 which at least partially surrounds the magnetic coil. In contact with the end face 18 of the valve housing I is a spacer ring 19, to which a guide diaphragm 20 is connected. The other side of the guide diaphragm is engaged by the collar 21 of the valve casing, so that
This provides a force for axially tightening the spacer ring 19 and the guide diaphragm 20 in position. The valve housing 1 has a coaxial receiving bore 25 into which a nozzle body 26 is inserted and fixed, for example by welding or soldering. The nozzle body 26 has a blind-hole-shaped, preferably cylindrical, regulating bore 28, in the bore bottom 30 of which there is at least one fuel guide bore 29 for fuel metering. It's open.

The fuel guide hole 29 advantageously opens into the bottom 30 of the regulating hole 28 in the following manner. This means that the inflow into the regulating hole 28 does not take place tangentially, but instead the fuel jet flows out of the fuel guide hole 29 without breaking or contacting the wall and then impinges on the wall of the regulating hole 28, resulting in The fuel guide hole opens at the bottom of the hole so that the fuel is distributed in a membrane through the gap adjustment hole 28 and flows toward the nozzle end 31 in a substantially parabolic shape.

The fuel guide hole 29 extends slightly relative to the valve axis, starts from a spherical chamber 32 formed in the nozzle body 26, and extends into the nozzle body 26 on the upstream side of this chamber. A seat 33 is formed; 1. A spherical valve seat 31 cooperates with the valve seat 33. In order to obtain as little punt space as possible, the volume of the bulb-shaped chamber 32 is made as small as possible when the valve part 34 is in contact with the valve seat 33.

On the side opposite the valve seat 33, the valve part 34 is connected to a flat armature 35, for example by soldering or welding. The flat armature can be formed as a stamping or as a V-shaped part and has, for example, an annular guide rim 36. The guide rim 36 is of projecting design and rests on the side of the diaphragm opposite the valve seat 33 in the annular guide region 38 of the guide diaphragm 20 . The flow openings 39 in the flat armature 35 and the flow recesses 40 in the guide diaphragm 20 allow the fuel to flow through the flat armature and the guiding diaphragm 20 without any hindrance. The guide diaphragm 20, which is clamped immovably on the housing between the spacer ring 19 and the boxwood 21 on its outer circumference, has a centering area 42, which surrounds the centering hole +3. And,
A movable valve part 34 projects through the centering hole 43 and is centered in the radial direction. The immovable fixing of the guide diaphragm to the casing between the spacer ring and the collar is achieved through the center point of the spherically formed valve part with the valve part 34 in contact with the valve seat 33 or at the center point. It is carried out in a plane extending as close as possible to the By means of the guiding region 38 of the guide diaphragm 20 acting on the guide rim 36 of the flat armature 35, the flat armature is guided as far as possible parallel to the end face 18 of the valve housing 1;
As a result, the flat armature is partially covered by the outer active area 44. A compression spring 45 is guided in the inner bore 6 of one of the fuel tubes extending near the flat armature 35 1, which compression spring 5 acts on the flat armature 35 on the one hand and on the adjusting sleeve 7 on the other hand. and loads the valve portion in the direction toward the valve seat 33. The fuel tube piece used as the inner core is designed in particular in such a way that a small air gap is obtained between the end face 46 facing the flat armature 35 and the flat armature, i.e. in the outer working area of the flat armature when the magnetic coil is energized. is attracted to the end face 18 of the valve casing 1, and even if the flat mover is loaded by the compression spring 45 in the direction of the valve seat 33 with the magnetic coil de-energized, there will be a gap between the end face 46 and the flat mover. Valve casing T so that a small air gap is obtained
pushed inside. The magnetic circuit runs externally via the valve housing and internally via the fuel tube and is closed via the flat armature 35.

For the flat armature, the end face 18 of the valve housing 1 forms a strike surface 729 on which, according to the invention, a thin polyimide sheet 48 is arranged.

The polyimide sheet 48 may be formed as a ring and cover approximately only the end face 18 of the valve casing, or it may be formed circularly and thus extend over the end face 46 of one of the fuel tubes, in which case the Through holes 49 are provided in the polyimide sheet for flow through. A defined residual gap is formed in the end face 18 of the valve housing by the polyimide sheet 4δ, which ensures a rapid fall of the flat armature at the end of excitation. The advantage of polyimide notebooks is that polyimide sheets can be produced in almost any shape with very small thickness tolerances and have extremely satisfactory resistance to impact loads and fuels. Since the polyimide sheet cushions the metal parts that collide with each other, that is, the stopper surface and the flat movable element, damage to the metal parts is reduced. Furthermore, since the metal parts are separated by an intermediate polyimide sheet, frictional erosion on the metal parts is avoided.

Effects of the Invention The advantage of the valve according to the invention is that it provides a residual gap with extremely small thickness tolerances and at the same time it is possible to dampen metal parts that collide with each other without causing frictional erosion. Moreover, the polyimide notes can be punched out in almost any desired shape.

Advantageous embodiments of the invention are set out in the claims 2, 3 and 4.

[Brief explanation of drawings]

The drawing is a sectional view of the valve according to the present invention in a state where it is used as a fuel injection valve.

Claims (4)

[Claims] 1. A valve casing (1), a core (4) of ferromagnetic material and an armature (35) for operating a valve part (34) cooperating with a stationary valve seat are provided, said armature An electromagnetically operable valve configured to be drawn to a stopper surface when a magnetic coil is excited, characterized in that a polyimide sheet (48) is disposed on the stopper surface (18, 46). Valve that can be operated manually. 2. The stopper surface is the end surface (18) of the valve casing (1)
A valve according to claim 1, comprising a portion of. 3. 3. A valve according to claim 1, wherein a polyimide sheet (48) is arranged on the core (4) on the side facing the armature (35). 4. 4. A valve according to claim 3, wherein the polyimide sheet (48) has through openings (49).