CN111810332A - Valves for dosing fluids - Google Patents

Abstract

The invention relates to a valve (1) for dosing a fluid, in particular a fuel injection valve for an internal combustion engine, comprising a housing (6), an actuator (2) and a valve needle (15), The valve needle can be actuated along the longitudinal axis ( 8 ) against the return spring ( 30 ) by the armature ( 4 ) of the actuator ( 2 ), wherein the armature ( 4 ) is driven by the armature ( 4 ). The outer side (43) is at least partially guided on the inner wall (42) of the housing (6). The valve is designed such that at least one partial surface (44) of the outer side (43) of the armature (4) lies at least approximately in a spherical surface (47), wherein at least when the armature (4) is in the When oriented axially on the longitudinal axis ( 8 ), the guide of the armature ( 4 ) takes place on the partial surface ( 44 ), which is located at least approximately in the spherical surface ( 47 ).

Description

Valves for dosing fluids

technical field

The invention relates to a valve for dosing fluids, in particular a fuel injection valve for internal combustion engines. In particular, the invention relates to the field of injectors for fuel injection devices of motor vehicles, in which fuel is preferably injected directly into the combustion chamber of an internal combustion engine.

Background technique

A fuel injection valve for a fuel injection system of an internal combustion engine is known from DE 10 2016 225 776 A1. Known fuel injection valves comprise a valve needle with a valve closing body, which cooperates with a valve seat surface to form a sealing seat, and an armature which is arranged on the valve needle. Stop elements are arranged on the valve needle, between which stop elements the armature can move in relation to the free path of the armature. In one embodiment, the valve needle is guided relative to the longitudinal axis or relative to the housing by means of a stop element located further away from the sealing seat in the guide region on the inner bore of the inner pole. The armature has a through hole. At the through hole, the armature is guided on the valve needle. Furthermore, the fuel injector has a return spring which, via the stop element, adjusts the valve needle into its initial position in which the sealing seat is closed. In a modified configuration, the valve needle is guided by the armature. In this case, the outer side of the armature reaches at least partially the inner side of the housing, wherein instead of a guide region, an annular gap can be realized between the stop element further away from the sealing seat and the inner pole.

SUMMARY OF THE INVENTION

The invention proposes a valve for dosing a fluid, in particular a fuel injection valve for an internal combustion engine, which valve has a housing, an actuator and a valve needle which can be driven by an armature of the actuator Actuation along a longitudinal axis against a return spring, wherein the armature is guided with its outer side at least partially on the inner wall of the housing, wherein at least a partial surface of the outer side of the armature lies at least approximately in a spherical surface , wherein, at least when the armature is oriented axially on the longitudinal axis, the armature is guided on the partial surface which lies at least approximately in the spherical surface. The valve according to the invention has the advantage that an improved configuration and way of operation can be achieved. In particular, the ejection properties can be improved.

An advantageous development of the valve proposed by the invention can be achieved by the measures listed in the preferred embodiments.

The valve is preferably used for dosing fluids, in particular liquid fuels. Gasoline or mixtures with gasoline are particularly suitable as fuel. Here, the fuel is preferably injected directly into the combustion chamber of the internal combustion engine. The liquid fluid can flow through the armature chamber in which the armature is arranged and thus contribute to damping of the armature. However, a modified configuration is also conceivable in which, for example, a suitable pressure fluid is present in the armature chamber. Thus, by selecting a corresponding configuration, suitable liquids and, if necessary, gases can be dosed.

The valve has an electromagnetic actuator with an armature arranged on the valve needle, wherein the armature is not fixedly connected to the valve needle, but is mounted floatingly between two stops arranged on the valve needle. between. Here, an axial play is specified between the armature and the two stops, which is referred to as the armature free path. Due to the armature free path, the armature can be held at the stop closer to the sealing seat in the resting state, so that when the actuator is subsequently actuated and when the armature is actuated, preferably the entire armature free path is available for the acceleration stroke .

This configuration with the free path of the armature has several advantages. Due to the pulses formed by the armature during opening, the valve needle can be reliably opened even at higher fluid pressures, in particular fuel pressures, with equal magnetic forces, which constitutes a mechanical booster. Furthermore, the moving mass can be decoupled so that the stop force is divided into two pulses, resulting in less seat wear. Furthermore, especially in highly dynamic valves, a collision tendency of the armature can be achieved by means of the mass decoupling.

When the solenoid of the actuator is energized, the armature is attracted to the inner pole of the actuator. The guide hole for guidance along the longitudinal axis is preferably formed on the inner pole. As a result, the valve needle can advantageously be supported radially on the inner pole. In a preferred configuration, this guidance is effected by a guide element connected to the valve needle, which guide element simultaneously serves as a stop element for the armature. This guidance of the valve needle on the inner pole by the guide element enables the valve needle to be supported in the housing, which is not carried out by means of the armature, so that a gap between the armature and the valve needle or between the armature and the housing is avoided from the outset. the corresponding radial force. This avoids wear on the radial guide between the armature and the valve needle or between the armature and the valve housing.

Between the outside of the armature and the inner wall of the housing, a support of the armature in the housing is advantageously achieved, which on the one hand enables an axial movement of the armature between stops arranged on the valve needle along the longitudinal axis and on the other hand On the one hand, an inclination of the armature can be achieved, which preferably corresponds to the principle of a ball bearing.

For example, for the manufacture of the valve, certain tolerance ranges can be specified for the configuration of the stop surfaces in which the armature participates. This relates in particular to the stop surface of the stop element on which the armature rests at the start of the actuation or exactly at the stop element and the stop surface at the inner pole. Deviations from the ideal vertical orientation of the stop surfaces on the longitudinal axis may arise as a result of manufacture. In particular, the stop surfaces cannot thus be oriented parallel to each other. The bearing of the armature on the inner wall of the housing, which is implemented according to the principle of ball bearing, can cause a tilting of the armature during injection with one or more actuations of the valve needle due to the orientation of the stop surfaces without, for example, due to edges. increased wear due to load.

According to a preferred embodiment, viewed along the longitudinal axis, the partial surface of the outer side of the armature which lies at least approximately in the spherical surface is arranged in a first axial section of the armature, which is located on the side of the armature. between the first end side and the second end side of the armature. Furthermore, the first axial section of the armature is spaced apart from the first end face and/or the first axial section of the armature is spaced apart from the second end face. In these developments according to the invention, it is particularly advantageous if the first axial section of the armature is realized as an intermediate axial section which is connected both to the first end side of the armature and to the second end of the armature. The ends are spaced apart. A correspondingly suitable configuration of the outer side of the armature can be achieved between the first axial section or the central axial section and the two end sides. In particular, it is conceivable to keep the gap between the outer side of the armature and the inner wall of the housing as small as possible or as small as possible in order to achieve a high magnetic flux density when the solenoid coil is energized.

According to a preferred embodiment, a further axial section is provided between the first axial section and the first end face of the armature, in which further axial section the armature faces the first The direction of the end face tapers, and/or a further axial section is provided between the first axial section and the second end face of the armature, in which further axial section the armature is on its outer side The upper part tapers toward the second end side. In this case, the development according to the invention has the advantage that the armature can be tilted over a preferably large range or with a preferably large tilt angle. It is particularly suitable here for the outer side of the armature to be conical in one of the further axial sections. Furthermore, one of the further axial sections extends from the first axial section to the first end face or from the first axial section to the second end face, according to this development of the invention it is advantageous if , each further axial section of the armature transitions uniformly into the first or intermediate axial section. As a result, the outer side of the armature can be configured in such a way that, viewed along the longitudinal axis, a tangential transition from a cone to a spherical radius or from a spherical radius to a cone takes place. The armature is correspondingly convex in its outer region. In an axial section viewed along the longitudinal axis, the outer side of the armature in the first section has a spherical radius-shaped configuration, to which the cone preferably adjoins on both sides. Therefore, when the outer side of the armature in one of the further axial sections is conical and/or one of the further axial sections extends from the first axial section to the first end side or from Significant advantages are obtained when the first axial section extends to the second end side.

According to a preferred embodiment, an inner pole is provided which is arranged in a fixed position in the housing, the armature abuts on the inner pole with its first end side during actuation, and the further axial section is between One or the other axial section is designed in such a way that the armature can be inclined and thus can rest flat on the abutment surface of the inner pole in order to compensate for certain manufacturing tolerances. This development according to the invention has the advantage that, even if the armature is inclined, the ball bearing is always achieved in the middle section. The at least one further axial section is not used for guiding the armature on the inner wall of the housing, but the inclination is effected by a wedge-shaped gap in profile. The at least one further axial section can be designed in such a way that a preferably small gap still results between the outer side of the armature and the inner wall of the housing. Furthermore, a stop element is provided which is preferably arranged in a fixed position on the valve needle, upon actuation the armature stops with its second end face on the stop element, and one or all of the further axial sections are The further axial section is designed in such a way that the armature can be inclined and thus can rest flat on the stop surface of the stop element in order to compensate for certain manufacturing tolerances. According to this development, the above-mentioned corresponding advantages are also obtained.

According to a preferred embodiment, the housing has a magnetic housing part, the inner housing wall extending over the magnetic wall region of the magnetic housing part, viewed along the longitudinal axis, and the first axial section of the armature is arranged in such a way that the Between the one end side and the second end side, viewed along the longitudinal axis, the first axial section is positioned at least approximately centrally with respect to the magnetic wall region. This development of the invention has the advantage that the magnetic flux density can be optimized when the coil is excited. This results in a further improvement in the switching behavior of the valve. Furthermore, when the armature is oriented on the longitudinal axis, a radial compensation play is specified between the armature and the valve needle, and/or the armature is always guided on a partial surface which lies at least approximately in the spherical surface. This development according to the invention also improves the switching behavior of the valve, wherein wear can also be reduced over the service life and thus a uniform switching behavior can be achieved.

The armature can advantageously be arranged in an armature chamber filled with liquid fluid in order to be able to dampen the movement of the armature. The liquid fluid may in particular be a fluid metered by a valve. The fluid to be dosed can, for example, be guided into the armature chamber through a guide hole of the inner pole. The armature can, for example, have through-holes through which the fluid can then be guided further to the sealing seat.

Description of drawings

Preferred embodiments of the invention are explained in detail in the following description with reference to the accompanying drawings, in which corresponding elements are provided with corresponding reference numerals. The attached figure shows:

Fig. 1 is a partial schematic cross-sectional view of a valve corresponding to one embodiment of the invention;

2 is a schematic cross-sectional view of the armature of the valve shown in FIG. 1;

FIG. 3 is a partial schematic view of the valve shown in FIG. 1 , with the armature at rest or resting on the stop element or resting on the stop element, in order to illustrate the operation of a possible configuration of the invention; and

FIG. 4 is a partial schematic view of the valve shown in FIG. 1 , with the armature abutting on the inner pole, to illustrate the operation of a possible configuration of the invention.

Detailed ways

FIG. 1 shows a partially schematic cross-sectional view of a valve 1 for dosing fluids according to an exemplary embodiment. In particular, the valve 1 can be designed as a fuel injection valve 1 . A preferred application is a fuel injection system in which such a fuel injection valve 1 is designed as a high-pressure injection valve 1 and is used to inject fuel directly into an associated combustion chamber of an internal combustion engine. The configuration of the valve 1 is particularly suitable for liquid fluids, in particular liquid fuels such as gasoline or diesel, or for liquid mixtures with at least one fuel.

The valve 1 has an electromagnetic actuator 2 comprising a solenoid coil 3 , an armature 4 and an inner pole 5 . When the solenoid coil 3 is energized, the magnetic circuit is closed via the housing (valve housing) 6 , the armature 4 and the inner pole 5 , whereby the armature 4 is actuated in the opening direction 7 along the longitudinal axis 8 of the housing 6 . The housing 6 comprises a housing part 9 , a valve seat body 11 connected to the housing part 9 and an inflow connection 12 .

The armature 4 is arranged on the valve needle 15 , wherein a floating bearing of the armature 4 on the valve needle 15 is achieved. For this purpose, stops are provided by means of stop surfaces 16 , 17 which are arranged in a fixed position on the valve needle 15 . The stop surfaces 16 , 17 are arranged on stop elements 18 , 19 which are each connected to the valve needle 15 , for example by welding or by pressing on the valve needle 15 . The stops 16 , 17 are arranged on the valve needle 15 in such a way that a free armature path 20 along the longitudinal axis 8 between the stops 16 , 17 is predetermined for the armature 4 ( FIG. 3 ).

In the initial state, the armature 4 rests on the stop 17 . During actuation of the armature 4 , the armature 4 first passes through the armature free path 20 until the armature 4 stops at the stop 16 . Subsequently, the armature 4 moves with the valve needle 15 in the opening direction 7 . This provides a larger opening pulse in order to open the valve 1 . When the valve 1 is open, the valve closing body 21 connected to the valve needle 15 is lifted from the valve seat surface formed on the valve seat body 11, so that the sealing seat formed between the valve closing body 21 and the valve seat surface opens . The fluid, in particular the fuel, can then be injected from the inner chamber 24 of the valve housing 6 into the chamber, in particular the combustion chamber of the internal combustion engine, through nozzle holes formed in the valve seat body 11 .

When the valve 1 is open, the armature 4 abuts against a stop surface 28 which is formed on the inner pole 5 . The stop surface 28 limits the movement of the armature 4 relative to the valve housing 6 . Here, the valve needle 15 can also be moved further in the opening direction and then vibrate back until the valve needle with its stop element 18 abuts the armature 4 again. To close the valve 1 , the solenoid coil 3 is de-energized, so that the valve needle 15 is again adjusted by the return spring 30 into the initial position shown in FIG. 1 . Return spring 30 may also be referred to as closing spring 30 or compression spring 30 . Furthermore, the return spring 30 is designed and mounted in such a way that it is under a predetermined preload in the initial position of the valve needle 15 , so that in the event of a de-energized solenoid coil 3 the closed valve seat is The initial position is loaded with the corresponding closing force. In the closed state, the armature free path spring 31 ensures the initial position of the armature 4 shown in FIG.

Thus, the valve needle 15 can be actuated by the actuator 2 against the force of the return spring 30 in order to open the valve 1 . When the valve 1 is opened and then closed, the valve needle 15 is guided. The valve needle 15 is guided on the one hand in the guide bore 33 of the inner pole 5 and on the other hand in the region of the valve seat body 11 by means of the stop element 18 , which here also serves as a guide element.

FIG. 2 shows a schematic sectional view of the armature 4 of the valve 1 shown in FIG. 1 . The armature 4 has a first section 34 , which in this embodiment is an intermediate section 34 . A further (second) section 36 is arranged between the first section 34 and the first end face 35 of the armature 4 . Furthermore, a further (third) section 38 is arranged between the intermediate section 34 and the second end face 37 of the armature 4 . Viewed along the longitudinal axis 8 , the center of the middle section 34 is arranged at a distance 39 from the second end face 37 . Here, the distance 39 is selected such that the middle section 34 of the armature 4 is located as centrally as possible in the magnetic region 40 ( FIG. 1 ) of the housing (valve housing) 6 , in which the magnetic flux flows in the armature 4 . and the transition between the housing 6 . Thus, the arrangement of the intermediate section 34 with respect to the magnetic region 40 of the housing 6 by the distance 39 concerns, in particular, the magnetic wall region 41 on the inner wall 42 of the housing 6 on which the armature 4 with its outer side 43 is located. is guided in the middle section 34 .

The outer side 43 is divided into three annular partial surfaces 44 , 45 , 46 corresponding to the sections 34 , 36 , 38 . The partial surface 44 is located in the spherical surface 47 . The partial surface 45 in the further section 36 is designed as a conical partial surface 45 which tapers in the opening direction 7 . The partial surface 46 in the further section 38 is designed as a conical partial surface 46 which tapers opposite to the opening direction 7 . When the armature 4 is oriented on the longitudinal axis 8 , wedge angles 48 , 49 of the conical partial surfaces 45 , 46 with respect to the longitudinal axis 8 or with respect to the inner wall 42 of the housing 6 are produced on the contour. The wedge angles 48 , 49 are specified as small as possible, so that the gap between the outer side 43 of the armature 4 and the inner wall 42 of the housing 6 is preferably small. However, the wedge angles 48 , 49 are here predetermined so large that the desired inclination of the armature 4 relative to the longitudinal axis 8 can be achieved. For example, the wedge angles 48 , 49 can each be specified with values of not more than 2° (and if necessary also with equal values).

FIG. 3 shows a partial schematic view of the valve 1 shown in FIG. 1 , with the armature 4 at rest or resting on the stop element 19 or resting on the stop element 19 , in order to illustrate a possible configuration of the invention. type of work. Here, the valve needle 15 and the longitudinal axis 8 are shown in an ideal orientation relative to the inner wall 42 of the valve housing 6 . For the sake of clarity, the stop element 19 is not shown in an ideal orientation. When the end face 37 of the armature 4 rests flat on the stop surface 17 of the stop element 19 , the inclined position of the stop element 19 is to be understood here as a schematic (not to scale) in the rest position A tilting of the armature 4 relative to the longitudinal axis 8 is caused. The partial surface 44 of the intermediate section 34 is chosen so large along the longitudinal axis 8 that even with such an inclination of the armature, the partial surface 44 located in the spherical surface 47 is guided relative to the inner wall 42 . During actuation, the ball bearing can advantageously rotate back or tilt back due to the hydraulic centering caused by the liquid fluid, which is located in the armature chamber 50 in which the armature 4 is arranged.

When the armature 4 is actuated, the armature free path 20 is passed, and the valve needle 15 is then entrained together with the stop element 18 . The stop then rests on the inner pole 5 , which is also shown here schematically (and not to scale) obliquely.

FIG. 4 shows a partial schematic view of the valve 1 shown in FIG. 1 , with the armature 4 abutting on the inner pole 5 , in order to illustrate the operation of a possible configuration of the invention. Here again, the inclination of the armature 4 occurs when the armature 4 with its first end side 35 rests flat against the stop surface 28 of the inner pole 5 . For the sake of clarity, the inclination here is the exact opposite of the situation shown in FIG. 3 . In this case, the wedge angles 48 , 49 are chosen so large that, even in the maximum inclined position (inclined) caused by tolerances, the armature 4 is prevented from being clamped or touched by one of the conical partial surfaces 45 , 46 . Hit the inner wall 42 . In this case, the diameter 51 of the spherical surface 47 can be specified at least approximately equal to the guide diameter 52 of the inner wall 42 of the housing 6 .

As shown in FIG. 1 , when the armature 4 is oriented on the longitudinal axis 8 , a radial compensation gap 53 is specified between the armature 4 and the valve needle 15 , which radial compensation gap can be provided, for example, via the annular gap 54 accomplish. In this case, the radial compensation gap 53 or annular gap 54 is preferably realized in such a way that the armature 4 is guided in the provided region on the outer side 43 even when tilted.

It can thus be ensured that the armature 4 is always guided on its outer side 43 during operation. In particular, it can be ensured that the armature 4 is always guided on the partial surface 44 of the outer side 43 of the armature which is located in the spherical surface 47 in the region of the predetermined inclination during operation. As a result, an advantageous ball bearing is always ensured during operation, which enables an advantageous inclination of the armature 4 and, if necessary, a hydraulic centering of the armature.

As a result, in particular edge loads can be avoided, which reduces the wear between the armature 4 and the housing 6 and can increase the switching force. Here, high opening and closing speeds and uniform switching behavior can be achieved in particular by a possible hydraulic centering of the armature 4 relative to the longitudinal axis 8 , which also has an effect on radial centering.

The invention is not limited to the described embodiments.

Claims (10)

1. A valve (1) for metering fluid, in particular a fuel injection valve for an internal combustion engine, having a housing (6), an actuator (2) and a valve needle (15) which can be actuated along a longitudinal axis (8) by an armature (4) of the actuator (2) counter to a return spring (30), wherein the armature (4) is guided with an outer side (43) of the armature (4) at least partially on an inner wall (42) of the housing (6),

it is characterized in that the preparation method is characterized in that,

at least one partial surface (44) of the outer side (43) of the armature (4) is located at least approximately in a spherical surface (47), wherein the armature (4) is guided on the partial surface (44) at least when the armature (4) is axially oriented on the longitudinal axis (8), said partial surface being located at least approximately in the spherical surface (47).

2. The valve as set forth in claim 1, wherein,

it is characterized in that the preparation method is characterized in that,

viewed along the longitudinal axis (8), a partial surface (44) of an outer side (43) of the armature (4), which is located at least approximately in the spherical surface (47), is arranged in a first axial section (34) of the armature (4), which is located between a first end face (35) of the armature (4) and a second end face (37) of the armature (4).

3. The valve as set forth in claim 2, wherein,

it is characterized in that the preparation method is characterized in that,

the first axial section (34) of the armature (4) is spaced apart from the first end face (35) and/or the first axial section (34) of the armature (4) is spaced apart from the second end face (37).

4. The valve according to claim 2 or 3,

it is characterized in that the preparation method is characterized in that,

between the first axial section (34) and the first end face (35) of the armature (4) a further axial section (36) is provided, in which the armature (4) tapers on its outer side (43) in the direction of the first end face (35), and/or between the first axial section (34) and the second end face (37) of the armature (4) a further axial section (38) is provided, in which the armature (4) tapers on its outer side (43) in the direction of the second end face (37).

5. The valve as set forth in claim 4,

it is characterized in that the preparation method is characterized in that,

the outer side (43) of the armature (4) is conical in at least one of the further axial sections (36, 38).

6. The valve according to claim 4 or 5,

it is characterized in that the preparation method is characterized in that,

at least one of the further axial sections (36, 38) extends from the first axial section (34) to the first end face (35) or from the first axial section (34) to the second end face (37).

7. The valve according to any one of claims 4 to 6,

it is characterized in that the preparation method is characterized in that,

an inner pole (5) is arranged in a stationary manner in the housing (6), wherein the armature (4) is stopped by a first end face (35) thereof during operation, and wherein one of the further axial sections (36, 38) or the further axial sections (36, 38) is designed in such a way that the armature (4) can be tilted and thus can be stopped flat against a stop surface (28) of the inner pole (5) in order to compensate for certain manufacturing tolerances.

8. The valve according to any one of claims 4 to 7,

it is characterized in that the preparation method is characterized in that,

a stop element (19) which is preferably arranged in a stationary manner on the valve needle (15) is provided, on which stop element the armature (4) is stopped with its second end face (37) during operation, and one of the further axial sections (36, 38) or the further axial sections (36, 38) is designed in such a way that the armature (4) can be tilted and thus can be stopped flat against a stop surface (17) of the stop element (19) in order to compensate for certain manufacturing tolerances.

9. The valve according to any one of claims 2 to 8,

it is characterized in that the preparation method is characterized in that,

the housing (6) has a magnetic housing part (9), wherein, as seen along the longitudinal axis (8), an inner wall (42) of the housing (6) extends over a magnetic wall region (41) of the magnetic housing part (9), and wherein a first axial section (34) of the armature (4) is arranged between the first end face (35) and the second end face (37) in such a way that, as seen along the longitudinal axis (8), the first axial section (34) is positioned at least approximately centrally relative to the magnetic wall region (41).

10. The valve according to any one of claims 1 to 9,

it is characterized in that the preparation method is characterized in that,

when the armature (4) is oriented on the longitudinal axis (8), a predetermined radial compensation gap (53) is predefined between the armature (4) and the valve needle (15), and/or the armature (4) is always guided on the partial surface (44) which is located at least approximately in the spherical surface (47).

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