DE102014221357A1 - Electromagnetically operated suction valve, high-pressure pump with such a suction valve and method for connecting such a suction valve with a housing part of a high-pressure pump - Google Patents

Abstract

The invention relates to an electromagnetically operated suction valve (1) for a high-pressure pump in a fuel injection system, in particular a common rail injection system, comprising a magnetic coil (2) for acting on a liftable armature (3) which can be coupled to a valve stem (4) , which is received in a liftable manner in an axial bore (5) of a valve plate (6), further comprising a valve screw (7) for axially fixing the position of the valve plate (6) in a housing part (8) of the high-pressure pump. According to the invention, the valve screw (7) is penetrated by an axial bore (9), via which the armature (3) is guided so as to be free of impact. The invention relates to a high pressure pump for a fuel injection system, in particular a common rail injection system, with such a suction valve (1) and a method for connecting such a suction valve (1) to a housing part (8) of a high pressure pump.

Description

The invention relates to an electromagnetically operated suction valve for a high pressure pump in a fuel injection system, in particular a common rail injection system, with the features of the preamble of claim 1. Furthermore, the invention relates to a high pressure pump for a fuel injection system, in particular a common rail injection system with such a suction valve. Furthermore, a method for connecting such a suction valve with a housing part of a high pressure pump is proposed.

State of the art

High-pressure pumps in a fuel injection system serve to deliver fuel to high pressure. For this purpose, a high-pressure pump has at least one pump element with a high-pressure element space, in which the fuel is compressed. The fuel delivered for high pressure is then fed via a high-pressure outlet to a high-pressure accumulator, the so-called rail. The filling of the high pressure element space is usually via a suction valve, which may be designed, for example, as an electromagnetically operable valve. This can be controlled such that the high-pressure element space a defined amount of fuel is supplied.

From the DE 10 2012 224 439 A1 For example, a high pressure pump for a fuel injection system, in particular a common rail injection system, with an electromagnetically controllable suction valve, which is accommodated in a hollow cylindrical projection of a cylinder head formed as a housing part of the high-pressure pump. The suction valve comprises a valve plate with an axial bore, in which a valve closing element in the form of a valve stem is received in a liftable manner. The valve closure member is connected to an armature surrounding a seat distal end of the valve closure member. An on the one hand at the armature, on the other hand supported on the valve plate compression spring acts on the valve closure member with a closing force. To open the suction valve, a magnetic coil is provided, which acts upon energization of the armature, so that it moves against the spring force of the compression spring and lifts the valve stem from the seat. The stroke of the armature is limited by a shoulder of a valve screw, which serves to fix the position of the valve plate in the housing part of the high-pressure pump. For this purpose, the valve screw is screwed into the hollow cylindrical projection of the housing part of the high-pressure pump and supported in the axial direction on the valve plate, so that an axial prestressing force is applied to the valve plate.

By applying the axial biasing force, the valve screw is subject to plastic deformation. This means that the valve screw is subjected to a setting process. The setting amount in turn has an influence on the stroke of the valve closing element or of the valve tappet and thus has an effect on the quantity of fuel supplied to the high-pressure element chamber. The setting behavior of the valve screw is a strongly fluctuating and unpredictable quantity.

Based on the above-mentioned prior art, the present invention seeks to provide an electromagnetically actuated suction valve with a valve screw for fixing in a housing part of a high-pressure pump in which the setting behavior of the valve screw has a significantly reduced or no influence on the stroke of the valve stem ,

To solve the problem, the electromagnetically actuated suction valve with the features of claim 1 and a high-pressure pump with such a suction valve are proposed. In addition, a method for connecting such a suction valve with a housing part of a high pressure pump is specified. Advantageous developments of the invention can be found in the respective subclaims.

Disclosure of the invention

The proposed electromagnetically actuated suction valve comprises a magnetic coil for acting on a liftable armature which can be coupled with a valve tappet, which is received in a liftable manner in an axial bore of a valve plate. Furthermore, the proposed suction valve comprises a valve screw for axially fixing the position of the valve plate in a housing part of the high-pressure pump. According to the invention, the valve screw is penetrated by an axial bore, via which the armature is guided so that it stops. This means that the valve screw itself does not form a stop for the armature. A limitation of the armature stroke is effected in the proposed suction valve by other, hereinafter described elements. Due to the non-stop guidance of the armature within the valve screw, the seating behavior of the valve screw exerts no influence on the stroke of the armature. The same therefore also applies to the stroke of the valve tappet, which can be coupled or coupled with the armature. The armature stroke is thus decoupled from the setting behavior of the valve screw.

Preferably, the axial bore of the valve screw for guiding the armature has a constant inner diameter. By this measure, a stop-free guidance of the armature is ensured by the valve screw. Furthermore, the Constant internal diameter of the axial bore of the valve screw to set the axial position of the armature according to the respective requirements. The constant inner diameter also simplifies the design of the valve screw, which is thus easier and less expensive to manufacture.

Further preferably, an end face of the valve plate facing the armature forms a stop surface serving as a lower stroke stop for the armature. The stroke of the armature in the opening direction is therefore limited by the valve plate. Due to the coupling of the valve stem with the anchor, the same applies to the opening stroke of the valve stem. Preferably, the armature has a hollow cylindrical portion, which is further preferably designed to be flush on the outer peripheral side and has a valve plate facing annular end face which cooperates stop-forming with the stop surface of the valve plate. On the one hand, the weight of the armature can be reduced over the hollow cylindrical portion, which has a favorable effect on the moving masses and thus on the dynamics of the suction valve. On the other hand, within the hollow cylindrical portion at least partially the valve stem and a spring acting on the valve stem in the closing direction can be accommodated.

To further reduce the weight of the armature is proposed that an armature facing end surface of an axially applied to the valve plate spacer sleeve serving as a lower stroke stop for the anchor abutment surface forms. By arranging a spacer sleeve between the valve plate and the armature, the anchor can be made shorter. This leads to a further optimization of the moving masses. The spacer sleeve also represents a simple and inexpensive to manufacture component that is customizable in terms of material and dimensions to the respective requirements. For example, a sintered material for forming the spacer sleeve can be selected to ensure a high strength of the stop surface to reduce wear in this area. About the dimension of the spacer sleeve in the axial direction of the stroke stop can be set according to the respective requirements.

The spacer sleeve preferably has an outer diameter which substantially corresponds to the outer diameter of the armature. This means that the spacer sleeve is formed on the outer circumference flush with the anchor. In this case, the outer diameter is preferably selected such that the spacer sleeve, which is received as the armature in the axial bore of the valve screw, in the axial direction relative to the valve screw is displaceable. The axial displaceability of the spacer sleeve relative to the valve screw ensures that the setting behavior of the valve screw has no influence on the axial position of the spacer sleeve with respect to the valve plate.

Both the limitation of the armature stroke directly over the valve plate, as well as the stroke limitation on the spacer sleeve have the advantage that after fixing the position of the valve plate in the housing part of the high-pressure pump by means of the valve screw, the axial position of the valve plate or the spacer sleeve supported thereon is fixed, and Although independent of the setting behavior of the valve screw. The setting behavior of the valve screw therefore has no influence on the lower stroke stop of the armature or the opening stroke of the valve tappet coupled to the armature.

According to a preferred embodiment of the invention, a pole core, which is accommodated in the magnet coil at least in regions, or a residual air gap disk supported thereon, forms a stop surface serving as an upper stroke stop for the armature. About the pole core or the residual air gap disc, therefore, the upper stroke stop of the anchor is specified.

In a further development of the invention it is proposed that the pole core is force, positively and / or cohesively connected to the valve screw. A non-positive connection can be effected for example via a press connection. This is easy to manufacture and at the same time allows an adjustment of the total stroke of the anchor via the press-in depth. A positive connection can be made in particular via a screw connection. The polar body is preferably screwed into the valve screw for this purpose. On the other hand, the total stroke of the armature can be adjusted via the screw-in depth. Alternatively or additionally, a cohesive connection, for example a welded connection, can be provided, which at the same time ensures a seal in the case of a circumferential weld seam. A seal can also be effected via an adhesive connection, which can also be used as an alternative or in addition to the use.

In order to prevent the setting behavior of the valve screw has influence on the position of the upper stroke stop, it is proposed that the polar body connected to the valve screw only after completion of setting process. If the valve screw has been set, compensation for the setting amount can be made, for example, via the press-in or screw-in depth of the polar body within the valve screw.

According to a preferred embodiment of the invention, the pole core is screwed via an external thread with an internal thread of the valve screw, wherein preferably the outside and the Internal thread are designed as a fine thread. A fine thread allows a very accurate adjustment of the axial position of the pole body with respect to the valve screw and thus the total stroke of the armature.

Advantageously, the armature has an anchor pin for mechanical coupling with the valve lifter. By the anchor pin, the moving masses can be further reduced. The anchor pin is preferably pressed into the armature, it being possible to influence the stroke of the valve tappet coupled to the armature via the press-in depth.

Further preferably, the armature is acted upon in the direction of the valve stem by the spring force of a compression spring. The suction valve is thus preferably a normally open valve. To close the valve, the solenoid must be energized so that the armature moves against the spring force of the compression spring in the direction of the pole core to close a working air gap between the pole core and the armature. To open the valve, the energization of the solenoid is terminated, so that the spring force of the compression spring returns the armature to its original position. The valve tappet coupled to the armature is lifted out of its seat counter to the spring force of a further spring supported on the valve tappet.

The further proposed for a fuel injection system, in particular a common rail injection system, high-pressure pump with an electromagnetically actuated suction valve according to the invention comprises a housing part having a receiving bore in which the valve plate is inserted and axially biased in the direction of a shoulder. The axial biasing force is effected via the valve screw, which is screwed into the receiving bore. The valve screw is in this case axially supported on the valve plate, wherein it deforms plastically in the region of the support. That is, the valve screw is subject to a setting process, but due to the design of the suction valve according to the invention has no effect on the stroke of the armature and the valve tappet coupled to the armature. Consequently, the setting behavior of the valve screw also has no influence on the high pressure pump supplied amount of fuel.

In the additionally proposed method for connecting an electromagnetically actuated suction valve according to the invention with a housing part of a high-pressure pump, the valve plate with preassembled valve stem is first inserted into a receiving bore of the housing part and axially biased by screwing the valve screw into the receiving bore in the direction of a shoulder of the housing part. Subsequently, the spacer sleeve and / or the armature is inserted into the axial bore of the valve screw. After completion of setting process of the pole core is force, positively and / or cohesively connected to the valve screw. This ensures that the setting behavior of the valve screw also has no influence on the axial position of the upper stroke stop, which is formed by the pole core itself or a rest air gap disc supported thereon.

Preferably, a connection of the pole core is effected with the valve screw by means of a screw or press connection, wherein preferably via the respective screwing or Einpresstiefe the total stroke of the armature is adjusted. The total stroke of the armature is precisely adjustable in this way, as well as any component tolerances of the suction valve on the screw or Einpresstiefe be compensated.

Further preferably, alternatively or additionally, a connection of the pole core with the valve screw is effected by means of an adhesive or welded connection. Because with a circumferential adhesive or weld seam can be effected at the same time a seal.

Preferred embodiments of the invention are described below with reference to the accompanying drawings. These show:

1 a schematic longitudinal section through an inventive electromagnetically actuated suction valve according to a first preferred embodiment of the invention, attached to a high-pressure pump, and

2 a schematic longitudinal section through an inventive electromagnetically actuated suction valve according to another preferred embodiment of the invention when attached to a high-pressure pump.

Detailed description of the drawings

That in the 1 schematically shown electromagnetically actuated suction valve 1 includes an annular solenoid 2 that at least partially a pole core 13 surrounds. Outside circumference is the magnetic coil 2 from a pot-shaped housing 22 surrounded, to form an electrical connection 23 is encapsulated with a plastic material.

By means of the magnetic coil 2 can on an anchor 3 be acted, with one in an axial bore 5 a valve plate 6 of the suction valve 1 Hubbeweglich recorded valve tappet 4 can be coupled. The valve lifter 4 opens directly into a high-pressure element space 24 a high-pressure pump to which the suction valve 1 is grown. For this purpose, the valve plate 6 including the valve lifter 4 in a receiving hole 20 a housing part 8th the high pressure pump used and by means of a in the receiving bore 20 screwed valve screw 7 in the direction of a paragraph 21 of the housing part 8th axially biased. Between the paragraph 21 and the valve plate 6 is still a spacer 25 inserted, via which the axial position of the valve plate 6 with respect to the housing part 8th can be specified.

The valve screw 7 is from an axial bore 9 interspersed, in which the anchor 3 not only received but also led. The inner diameter of the axial bore 9 is over the entire height of the valve screw 7 consistent. This allows one to anchor 3 facing end face 10 the valve plate 6 as the lower stroke stop for the anchor 3 can serve. The anchor 3 is in one of the frontal area 10 the valve plate 6 facing hollow section executed, which has a favorable effect on the moving masses. The coupling with the valve lifter 4 is realized via a radially inner, sleeve-shaped projection, which is a seat remote end of the valve stem 4 surrounds.

The use of the face 10 the valve plate 6 as the lower stroke stop for the anchor 3 has the advantage that the setting behavior of the valve screw 7 , by means of which the valve plate 6 in the direction of the paragraph 21 is axially biased, no influence on the stroke of the armature 3 or with the anchor 3 coupled valve stem 4 Has. This ensures that the high pressure element space 24 the high pressure pump a defined amount of fuel is supplied.

The total stroke of the anchor 3 is determined by an upper stroke stop. As the upper stroke stop in the present case serves a stop surface 15 at the pole core 13 is formed, at least partially in the magnetic coil 2 taken and also with the valve screw 7 is screwed. The screw connection is via an external thread 16 of the pole core 13 and an internal thread 17 causes the valve screw, the threads are designed as a fine thread. In this way, the total stroke of the anchor can be 3 set exactly.

The functioning of the in the 1 schematically illustrated suction valve 1 is as follows:
Will the solenoid coil 2 energized, builds up a magnetic field, whose magnetic force is the anchor 3 against the spring force of a compression spring 19 in the direction of the pole core 13 emotional. The valve lifter 4 is relieved, so that one on the valve lifter 4 supported further spring 26 the valve lifter 4 in a valve seat 27 pulls and the suction valve 1 closes. To open the suction valve 1 is the energization of the solenoid 2 completed. The anchor 3 is about the spring force of the compression spring 19 returned to its original position, where he the valve tappet 4 from the valve seat 27 lifts.

A further preferred embodiment of an electromagnetically actuated suction valve according to the invention 1 is in the 2 shown. Here is an end face 11 a spacer sleeve 12 as lower stroke stop. The spacer sleeve 12 is at the frontal area 10 the valve plate 6 axially supported and axially movable in the axial bore 9 the valve screw 7 so that the setting behavior of the valve screw 7 has no influence on the axial position of the lower stroke stop. By the arrangement of a spacer sleeve 12 between the anchor 3 and the valve plate 6 can the anchor 3 be shortened, which has a reduction in the moving mass result, the dynamics of the suction valve 1 improved. To a hydraulic and / or magnetic bonding of the anchor 3 at the pole core 13 when closing the suction valve 1 to prevent is between the pole core 13 and the anchor 3 a residual air gap disk 14 arranged. Such can optionally also in the embodiment of the 1 to be ordered.

The anchor 3 in the embodiment of the 2 is not only shorter, but also has a place in the anchor instead of a radially inner, sleeve-shaped approach 3 pressed anchor pin 18 for coupling with the valve lifter 4 on. The anchor 3 with the anchor pin 18 is due to the simple geometries particularly simple and inexpensive to manufacture.

With reference to the embodiment of the 2 will now be the inventive method for connecting a suction valve according to the invention 1 with a housing part 8th a high-pressure pump will be described.

First, the valve part of the suction valve 1 preassembled. For this purpose, the valve tappet 4 into the axial bore 5 the valve plate 6 used and with the spring 26 and a spring plate 28 countered. Subsequently, after inserting a spacer 25 the pre-assembled valve plate 6 in a receiving hole 20 of the housing part 8th used. This is followed by the insertion and screwing of the valve screw 7 with the housing part 8th , where the valve plate 6 in the direction of a paragraph 21 of the housing part 8th is axially biased.

After completion of the setting process, the actuators are mounted. For this purpose, first the spacer sleeve 12 into the axial bore 9 of the valve screw 7 used. This is followed by the insertion of the anchor 3 , After inserting the residual air gap disc 14 and the compression spring 19 becomes the pole core 13 used and with the valve screw 7 connected. The connection can be made for example by welding. Previously, the axial position of the pole core 13 in relation to the valve screw 7 specify exactly as this is the total stroke of the anchor 3 certainly. For this purpose, it may be advantageous that in addition to the welded connection a screw or press connection is provided, which precedes the welded joint. Because about the Einschraub- or Einpresstiefe the total stroke of the anchor 3 be set very precisely. The subsequent weld is then primarily the seal.

In the 2 not shown in the cup-shaped housing 22 recorded magnetic coil 2 which concludes the assembly on the pole core 13 is put on.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012224439 A1 [0003]

Claims (12)

Electromagnetically operated suction valve ( 1 ) for a high pressure pump in a fuel injection system, in particular a common rail injection system, comprising a magnetic coil ( 2 ) for acting on a lifting anchor ( 3 ), which is equipped with a valve tappet ( 4 ) which can be coupled in an axial bore ( 5 ) a valve plate ( 6 ) is received liftable, further comprising a valve screw ( 7 ) for axially fixing the position of the valve plate ( 6 ) in a housing part ( 8th ) of the high-pressure pump, characterized in that the valve screw ( 7 ) from an axial bore ( 9 ), over which the anchor ( 3 ) is guided without a stop. Suction valve according to claim 1, characterized in that the axial bore ( 9 ) of the valve screw ( 7 ) for guiding the anchor ( 3 ) has a constant inner diameter. Suction valve according to claim 1 or 2, characterized in that an armature ( 3 ) facing end face ( 10 ) of the valve plate ( 6 ) as a lower stroke stop for the anchor ( 3 ) serving stop surface forms. Suction valve according to claim 1 or 2, characterized in that an armature ( 3 ) facing end face ( 11 ) one axially on the valve plate ( 6 ) adjoining spacer sleeve ( 12 ) as a lower stroke stop for the anchor ( 3 ) serving stop surface forms. Suction valve according to one of the preceding claims, characterized in that an at least partially in the magnetic coil ( 2 ) picked up pole core ( 13 ) or a residual air gap disc supported thereon ( 14 ) one as the upper stroke stop for the anchor ( 3 ) stop surface ( 15 ) trains. Suction valve according to claim 5, characterized in that the pole core ( 13 ) force, positive and / or material fit with the valve screw ( 7 ) connected is. Suction valve according to claim 5 or 6, characterized in that the pole core ( 13 ) via an external thread ( 16 ) with an internal thread ( 17 ) of the valve screw ( 7 ) is screwed, wherein preferably the outer and the inner thread ( 16 . 17 ) are formed as a fine thread. Suction valve according to one of the preceding claims, characterized in that the armature ( 3 ) an anchor pin ( 18 ) for mechanical coupling with the valve tappet ( 4 ) and / or in the direction of the valve stem ( 4 ) of the spring force of a compression spring ( 19 ) is acted upon. High-pressure pump for a fuel injection system, in particular a common rail injection system, with an electromagnetically actuated suction valve ( 1 ) according to one of the preceding claims, comprising a housing part ( 8th ) with a receiving bore ( 20 ), in which the valve plate ( 6 ) and towards a paragraph ( 21 ) is axially biased, wherein the axial biasing force via the valve screw ( 7 ) is brought into the receiving bore ( 20 ) is screwed. Method for connecting an electromagnetically actuated suction valve ( 1 ) according to one of claims 1 to 8 with a housing part ( 8th ) of a high pressure pump, wherein the valve plate ( 6 ) with preassembled valve stem ( 4 ) in a receiving bore ( 20 ) of the housing part ( 8th ) and by screwing the valve screw ( 7 ) in the receiving bore ( 20 ) in the direction of a paragraph ( 21 ) of the housing part ( 8th ) is axially biased, then the spacer sleeve ( 12 ) and / or the anchor ( 3 ) in the axial bore ( 9 ) of the valve screw ( 7 ) is / are used and only after completion of setting process of Polkern ( 13 ) force, form and / or material fit with the valve screw ( 7 ) is connected. Method according to claim 10, characterized in that a connection of the pole core ( 13 ) with the valve screw ( 7 ) is effected by means of a screw or press connection, wherein preferably over the respective Einschraub- or Einpresstiefe the total stroke of the armature ( 3 ) is set. Method according to claim 10 or 11, characterized in that a connection of the pole core ( 13 ) with the valve screw ( 7 ) is effected by means of an adhesive or welded connection.

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