WO2017067712A1

WO2017067712A1 - Armature assembly and electromagnetically actuatable valve, in particular suction valve

Info

Publication number: WO2017067712A1
Application number: PCT/EP2016/071546
Authority: WO
Inventors: Achim Meisiek; Stefan Kolb
Original assignee: Robert Bosch Gmbh
Priority date: 2015-10-20
Filing date: 2016-09-13
Publication date: 2017-04-27
Also published as: DE102015220387A1

Abstract

The invention relates to an armature assembly for an electromagnetic actuable valve, in particular for an electromagnetically actuable suction valve for filling a high pressure element chamber of a high-pressure pump with fuel, comprising a base body (1) consisting of a soft magnetic material and a contact pin (2) for contacting a reciprocating valve piston (20) of the valve. Said contact pin (2) comprises two parts (3, 4) which are interconnected and which are axially supported on the base body (1). The invention also relates to an electromagnetically actuable valve, in particular an electromagnetically actuable suction valve, with an armature assembly of said type.

Description

Description title

Armature assembly and electromagnetically operable valve, in particular Saugven- iil

The invention relates to an armature assembly for an electromagnetically operable valve, in particular for an electromagnetically actuated suction valve for filling a high pressure element space of a high-pressure pump with fuel. Furthermore, the invention relates to an electromagnetically operable valve, in particular an electromagnetically actuated suction valve for a high-pressure pump, with such an armature assembly.

State of the art

To ensure good magnetic properties, armatures are preferably made of a soft magnetic material. However, this material has

Deficits in terms of its resilience and its wear resistance. These deficiencies appear in particular when the magnet armature is subjected to high loads due to cavitation erosion and / or mechanical wear in the area of its stop and contact surfaces, as is the case for example in the application as a magnet armature in an electromagnetically actuated suction valve for filling a high-pressure Elementraums a high pressure pump with fuel is the case.

From the published patent application DE 10 2013 218 713 AI is an example of an electromagnetically actuated suction valve for a high pressure pump forth, which has a spring-loaded armature for actuating a liftable valve piston. To act on the spring-loaded anchor an electromagnet is provided. If the electromagnet remains de-energized, the suction valve is opened because the spring-loaded armature holds the valve piston in an open position. When the electromagnet is energized, a magnetic field builds up, the magnetic force of which forces the armature in the direction of the electromagnet. moved. In this case, the armature releases from the valve piston, so that this is relieved and pulled over the spring force of a valve spring in a valve seat. The suction valve closes. To open the suction valve, the energization of the electromagnet is stopped and the spring-loaded armature moves back to its original position. He strikes the valve piston and lifts it out of the valve seat.

The armature of such a suction valve is exposed to high stop pulses in the contact region with the valve piston and in the region of its stop surfaces cooperating with stroke stops. Due to the fast movement of the armature also form local vacuum areas, which can lead to the formation of gas bubbles. If the pressure then increases again, they implode and cause so-called cavitation erosion. Particularly at risk is the contact area of the armature with the valve piston.

In order to increase the wear resistance of an armature, magnet armatures are known from the prior art, which consist of a soft magnetic material and another material which is particularly durable. For example, DE 10 2011 088 132 A1 discloses a magnet armature for a magnet actuator which has a magnetic region made of a magnetic material with a high saturation induction and, for increasing the robustness, a region made of a ceramic material or a hard metal serving as a stop surface.

Based on the above-mentioned prior art, the present invention seeks to further increase the robustness of an armature for an electromagnetically operable valve, in particular an electromagnetically actuated suction valve.

To solve the problem, the armature assembly with the features of claim 1 is proposed. Advantageous developments of the invention can be found in the dependent claims. Furthermore, an electromagnetically operable valve, in particular an electromagnetically actuated suction valve, is specified with such an armature assembly. Disclosure of the invention

The proposed for an electromagnetically actuated valve, in particular for an electromagnetically actuated suction valve for filling a high-pressure element space of a high-pressure pump with fuel, anchor assembly comprises a base body made of a soft magnetic material and a contact pin for contacting a liftable valve piston of the valve. The contact pin comprises two parts which are axially supported on the base body and connected to each other.

The design of the armature as an armature assembly, that is, as a multi-part anchor, allows the use of different materials, so that the materials can be optimally adapted to the respective function of an anchor part. A first anchor part forms the main body, which should have good magnetic properties and is accordingly made of a soft magnetic material, for example of an iron-cobalt alloy. Another anchor part of the armature assembly according to the invention forms the contact pin for contacting a liftable valve piston. Since the contact pin is exposed to high loads, this is preferably made of a high-strength material that does not have to have magnetic properties relative to the material of the base body. The contact pin thus compensates for the deficiencies of the material of the body in terms of resilience and wear resistance and thus increases the robustness of the armature assembly.

To further increase the robustness of the armature assembly, the contact pin itself is also made of several parts. The contact pin comprises two parts which are braced axially against each other on the base body. This has the consequence that the body is only loaded axially. This means that the body undergoes no radial expansion of its outer diameter, as would be the case for example when pressing a contact pin. Negative effects on the bearing clearance of the armature, resulting from a radial expansion, are therefore not to be feared. Furthermore, a permanent connection of the two parts of the contact pin with the body is ensured on the mutual axial clamping. Preferably, the two parts of the contact pin are arranged coaxially with respect to a longitudinal axis A of the base body. The main body is thus loaded substantially centrally when the contact pin contacts the valve piston.

Furthermore, preferably, the two parts of the contact pin each have a collar portion for axial support on the base body. The collar portions form facing, annular support surfaces and allow in this way a mutual axial clamping of the two parts on the body.

Advantageously, the two parts of the contact pin are connected to one another via a press or screw connection. When pressing or when screwing the two parts, the desired axial bias can be effected in a simple manner, which only axially loaded the body.

Further preferably, the base body on a central recess for receiving at least a portion of the contact pin. The recess is dimensioned such that the base body undergoes no radial expansion through a part of the contact pin received therein. Preferably, the recess is designed as an axial bore, which passes through the base body. Because then the two parts of the contact pin to be connected can be inserted during assembly of two sides in the recess.

A first part of the contact pin is preferably axially supported on an end face of the main body. This means that at least a portion of the first part protrudes in front of the end face of the armature in the axial direction. The at least partially protruding first part therefore preferably serves the contacting of a liftable valve piston. For example, the contacting can take place via an end face of the first part axially spaced from the end face of the main body. In this way it is ensured that only the contact pin comes into contact with the valve piston.

Alternatively or additionally, it is proposed that a second part of the contact pin is supported on a shoulder of the base body, which is preferably formed within the central recess of the base body. The second part can do that be completely inserted into the body, for example, to counter the first part.

In a further development of the invention it is proposed that at least one pressure compensation opening is formed in the base body, which is preferably designed as an axial bore and passes through the base body. The pressure compensation opening causes a pressure equalization during a stroke of the armature assembly, so that the risk of cavitation at the stop and contact surfaces of the armature assembly is further reduced.

Further, an electromagnetically operable valve, in particular an electromagnetically actuated suction valve for filling a high pressure element space of a high-pressure pump with fuel with an armature assembly according to the invention and a valve body is proposed, in which the armature assembly is received liftable. About the valve body, a guide of the armature assembly can be effected.

Preferably, the armature assembly is acted upon by the spring force of a compression spring in the direction of a lower stroke stop, which is formed by a shoulder of the valve body or by a supported on the shoulder ring body. A return of the armature assembly can be effected via the compression spring. Preferably, the compression spring is supported on a part of the contact pin received in the main body. If this part is received in a central recess of the main body of the armature assembly, the central recess can also be used for receiving and guiding the compression spring.

In order to act on the armature assembly, the valve preferably further comprises an electromagnet having an annular magnet coil and an inner pole body inserted therein. The inner pole body can be used to form an upper stroke stop for the armature assembly.

In addition, it is proposed that the valve comprises a liftable valve piston which has a contact surface can be brought into contact with the end face. In this embodiment of the valve, the advantages of a Kerbaugruppe particularly well to bear, especially if the valve is an electromagnetically actuated suction valve.

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

1 shows a schematic longitudinal section through an electromagnetically actuated suction valve with an armature assembly according to a first preferred embodiment of the invention,

Fig. 2 is a schematic longitudinal section through an electromagnetically actuated suction valve with an armature assembly according to a second preferred embodiment of the invention and

Fig. 3 is a schematic longitudinal section through an inventive suction valve, which is integrated in a high-pressure pump for a fuel injection system.

Detailed description of the drawings

The electromagnetically actuated intake valve shown in FIG. 1 is used to fill a high-pressure pump with fuel. For this purpose, the suction valve is integrated into a housing part 22 of the high-pressure pump, which at the same time forms a valve seat 26 for the suction valve (see FIG. 3).

The suction valve of FIG. 1 comprises an electromagnet 16 for acting on a lifting armature group, the invention has a base body 1 made of a soft magnetic material and a two-part pin 2 made of a high-strength material. The first part 3 of the contact pin 2 is used to make contact with a liftable valve piston 20, which is acted upon by the spring force of a valve spring 24 in the closing direction. The valve spring 24 is for this purpose supported on the one hand on a spring plate 23, on the other hand on the housing part 22 of the high-pressure pump. The second part 4 of the contact pin 2 serves to hold the first part 3. For this purpose, both parts 3, 4 are axially supported on the base body 1 via collar sections 5, 6, wherein the support of the first part 3 via the collar section 5 is supported on the valve body. Ben 20 facing end face 8 of the base body 1 takes place, while the second part 4 is supported via the collar portion 6 on a shoulder 9 within a central recess 7 of the base body 1. To form the paragraph 9, the recess 7 is designed as a stepped bore. Both parts 3, 4 of the contact pin 2 are connected via a press connection. About the pressing force is also an axial

Tensioning of the two parts 3, 4 causes each other on the base body 1, so that the base body 1 is loaded only in the axial direction.

In the central recess 7 of the main body 1, a compression spring 15 is used, the spring force acts on the armature assembly in the direction of a lower stroke stop 12. The lower stroke stop 12 is presently formed by an annular body 14 which is supported on an annular shoulder 13 of a valve body 11.

If a magnetic coil 17 of the electromagnet 16 is energized, a magnetic field builds up, whose magnetic force moves the armature assembly counter to the spring force of the compression spring 15 upwards. An inserted in the solenoid 17 Innenpolkörper 18 forms an upper stroke stop 19 for the armature assembly. During the stroke of the armature assembly, the contact pin 2 releases from the valve piston 20 so that it is relieved and pulled over the spring force of the valve spring 24 in the valve seat 26. The suction valve closes. To open the suction valve, the energization of the solenoid 17 is terminated. The armature assembly is then returned by the spring force of the compression spring 15 in its initial position, wherein the contact pin 2 abuts against an end face 21 of the valve piston 20 and this lifts against the spring force of the valve spring 24 from the valve seat 26. In the open position of the suction valve, fuel can flow from a low-pressure space 25 into a high-pressure element space 27 of the high-pressure pump (see FIG. 3).

The two-part pin 2 made of a high-strength material increases the robustness of the armature assembly, so that it is less subject to wear. In particular, the robustness of the armature assembly in the contact area with the valve piston 20 is increased. Furthermore, the two-part embodiment of the contact pin 2 and the press connection of the two parts 3, 4 contributes to the fact that the load of the main body 1 is reduced. Because the main body 1 is only loaded axially. The risk of cavitation in rich of stop and contact surfaces of the armature assembly is further reduced by pressure equalization openings 10, which enforce the body 1.

FIG. 2 shows a further preferred embodiment of an armature assembly according to the invention for an electromagnetically actuated suction valve. The armature assembly differs from that of FIG. 1 in that the two parts 3, 4 of the contact pin 2 are not pressed together, but are screwed together. The first part 3 is provided for this purpose with an internal thread and the second part 4 with an external thread. Alternatively, the first part 3 could also have an external thread and the second part 4 could have an internal thread.

FIG. 3 shows a suction valve integrated into a high-pressure pump with an armature assembly according to the invention. The low pressure chamber 25 is formed as an annular recess in the housing part 22 of the high-pressure pump and is limited by the valve body 11 of the suction valve. The valve body 11 and the electromagnet 16 are fixed after insertion of the valve piston 20 in the housing part 22 with the aid of a union nut 28 on the housing part 22.

When the intake valve is open, fuel flows from the low-pressure chamber 25 via the valve seat 26 into the high-pressure element chamber 27 of the high-pressure pump. When the suction valve is closed, the fuel present in the high-pressure element space 27 is compressed by a lifting movement of a pump piston 29 whose end face delimits the high pressure element space 27. The compressed fuel is then fed via an outlet valve 30 to a high pressure accumulator (not shown).

Claims

claims

1. An armature assembly for an electromagnetically operable valve, in particular for an electromagnetically operable suction valve for filling a high pressure element space of a high-pressure pump with fuel, comprising a base body (1) of a soft magnetic material and a contact pin (2) for contacting a liftable valve piston (20) the valve,

wherein the contact pin (2) comprises two parts (3, 4) which are axially supported on the base body (1) and connected to each other.

2. An armature assembly according to claim 1,

characterized in that the two parts (3, 4) of the contact pin (2) are arranged coaxially with respect to a longitudinal axis (A) of the base body (1).

3. An armature assembly according to claim 1 or 2,

characterized in that the two parts (3, 4) of the contact pin (2) each have a collar portion (5, 6) for axial support on the base body (1).

4. An armature assembly according to one of the preceding claims,

characterized in that the two parts (3, 4) of the contact pin (2) are connected to each other via a press or screw connection.

5. An armature assembly according to one of the preceding claims,

characterized in that the base body (1) has a central recess (7) for receiving at least a part (3, 4) of the contact pin (2).

6. An armature assembly according to one of the preceding claims, characterized in that a first part (3) of the contact pin (2) on one end face (8) of the base body (1) is axially supported and / or a second part (4) of the contact pin ( 2) is supported on a shoulder (9) of the base body (1), which is preferably formed within the recess (7) of the base body (1).

7. An armature assembly according to one of the preceding claims,

characterized in that in the base body (1) at least one pressure equalization opening (10) is formed, which is preferably formed as an axial bore and the base body (1) passes through.

8. Electromagnetically actuated valve, in particular electromagnetically actuated suction valve for filling a high-pressure element space of a high-pressure pump with fuel, comprising an armature assembly according to one of the preceding claims and a valve body (11) in which the armature assembly is received liftable.

9. Valve according to claim 9,

characterized in that the armature assembly is formed in the direction of a lower stroke stop (12) which is formed by a shoulder (13) of the valve body (11) or by an annular body (14) supported on the shoulder (13) by the spring force of a compression spring (15 ) is acted upon, wherein preferably the compression spring (15) on a in the base body (1) accommodated part (4) of the contact pin (2) is supported.

10. Valve according to claim 8 or 9,

characterized in that the valve comprises an electromagnet (16) for acting on the armature assembly, the electromagnet (16) comprising an annular solenoid (17) and an inner pole body (18) inserted therein which preferably comprises an upper stroke stop (19) for the Anchor assembly forms.

11. Valve according to one of claims 8 to 10,

characterized in that the valve comprises a liftable valve piston (20) having an engageable with the contact pin (2) in contact face (21).