WO2002023036A1

WO2002023036A1 - Valve configuration for control valves

Info

Publication number: WO2002023036A1
Application number: PCT/EP2001/010685
Authority: WO
Inventors: Wolfgang Scheibe
Original assignee: L'orange Gmbh
Priority date: 2000-09-18
Filing date: 2001-09-15
Publication date: 2002-03-21
Also published as: DE10046416C2; DE10046416A1; ATE319003T1; DE50109103D1; EP1319127B1; EP1319127A1

Abstract

The invention relates to a valve configuration for control valves. Said valve configuration operates by means of graduated throttling using throttling points (5) which are arranged in the supply on the high pressure side (2) and in the discharge on the low pressure side (17). Said throttling is carried out by a blocking element (7, 32, 36) in order to avoid cavitation erosion.

Description

Valve design for control valves

The invention relates to a valve design for control valves according to the preamble of claim 1.

Valve designs of the aforementioned type are known from practice. Corresponding to the very high pressures to be mastered in injection systems for internal combustion engines, in particular accumulator pressure injection systems up to the order of 2000 bar, there are also growing problems for the control valves, since the valves located between the high and low pressure side with their blocking elements flowed from the high pressure side very much are exposed to high loads. In particular, the pressure gradient between the high and low pressure sides in the throttle point leads to high flow velocities with the tendency of the flow to cavitate with an increasing pressure drop in the outlet area on the blocking element, and when the impinging element hits the blocking element, pressure increases again due to the associated deflections and flow delays. This favors the imploding of the cavitation bubbles in the seat contact area of the locking member and the seat surface of the valve seat and causes corresponding cavitation erosion. Affected by this are the areas with the locking element and the valve seat which, due to their function, are also exposed to the highest mechanical loads, for example due to sudden action when the locking element hits the valve seat and the alignment of the locking element with respect to the seat surface during the centering of the locking process associated with the closing process Locking member opposite the seat.

The invention has for its object to improve a valve design of the type mentioned with regard to the problems mentioned and in particular to reduce the risk of cavitation erosion in such valve designs.

According to the invention, this is achieved by the features of claim 1, wherein use is made of the idea of largely eliminating the conditions for cavitation by means of stepped pressure reduction. For this purpose, it is provided that, based on the closed position of the locking element, the locking element adjacent to the seat contact zone is delimited against the low pressure side and throttled toward the low pressure side Connected recording room is assigned. The delimitation of this space opposite the seat contact zone can expediently also be a guide for the locking member and / or serve as a throttling point, so that the desired stepped throttling can also be achieved structurally with simple means and with little effort.

In the context of the invention, the locking member can be an independent component, or it can also be connected to the actuating movement transducer assigned to it, whereby plungers with a relatively small diameter in relation to their length can serve as the actuating movement transducer, so that the mutual alignment with the seat surface via the pressure plunger is not impaired becomes.

If the space delimitation of the second, throttle area on the outlet side opposite the seat surface also serves as a guide for the blocking element, then a stabilization of the flow conditions in the transition from the first throttle section to the blocking element can also be achieved, which also relates to the reduction or avoidance of the cavitation of the flow or cavitation erosion proves to be expedient.

Solid balls, ball segments or valve bodies tapering in the direction of the seat surface can be used as locking members in the context of the invention, a guide being expedient in particular for spherical locking members and especially for full-spherical locking members.

With regard to the realization of different, throttled connections of the receiving space at least partially surrounding the respective locking member

Low-pressure side valve seats in spherical or dome-shaped training or also in tapered training, in particular in flat-tapered training, can prove to be expedient, so that different throttle paths, possibly also combined, can be implemented, and this regardless of the respective type of training of the guide Part, which may also be designed as an aperture. In terms of construction, it may be expedient to assign the seat surface and the guide part following the seat part to separate components, for example to assign the guide part, in the sense of the above-mentioned aperture or also in the sense of a cylindrical guide, to a cover plate which connects to a valve plate containing the valve seat, channel connections serving as throttling points can be arranged between the cover plate and the valve plate.

The invention also makes it possible with simple means to make the throttle cross-section of the space delimited by the guide dependent on the stroke of the locking member, that is to say to create a throttle connection which varies in cross-section depending on the stroke, the corresponding cross-sectional changes also being made by appropriate shaping for the actuating movement transmitter in the form of an actuating plunger or pressure stamp and / or the locking member can be realized.

Further details and features of the invention emerge from the claims. Furthermore, the invention is explained in more detail below using an exemplary embodiment. Show it:

Figure 1 shows a schematic sectional view of the control valve

Injection injector, between the nozzle part and a magnetic actuator arranged opposite to this

Control valve is located, wherein the magnetic actuator on the control valve acts on a lifting movement actuator for the locking member, which controls a throttled inlet from a pressure chamber, with which the nozzle needle of the injection nozzle, which is acted upon on the high-pressure side via the injection medium, communicates with an actuating surface via which in the pressure chamber current pressure, the nozzle needle is loaded in addition to the closing spring in the closing direction, FIG. 2 shows an enlarged section A of an area of FIG. 1, which shows the actuating movement transmitter acting on the locking member and the associated area of the valve seat, FIG. 3 shows an embodiment of the invention corresponding to FIG

Blocking element and assigned valve seat area, FIG. 4 shows a section according to IV-IV in FIG. 3 in a schematic representation,

5 and 6 further configurations according to the invention in a representation corresponding to FIG. 4, wherein, analogously to FIG. 4, the locking member between the associated seat surface and axially spaced guide has a throttle chamber with throttle bores or throttle channels branching off from the seat surface region of the actuator, FIG. 7 shows a further embodiment according to FIG Invention in which the

Throttle cross sections are placed in the radial guide area of the axially movable locking member, FIG. 8 is a sectional view according to line Vll-Vll,

Figure 9 shows another embodiment of the invention, in which the

Throttle cross sections are variable as a function of the stroke of the locking member, and FIG. 10 shows a schematic sectional illustration along line X-X in FIG. 9.

FIG. 1 illustrates the control valve 1 of an injection injector, not shown, by means of which the injection valve associated with the injection injector is controlled. The high pressure side inlet connection to the control valve 1 is illustrated by the arrow 2. The inlet takes place via a bore 4 provided in a valve plate 3, which opens out onto a valve seat 6 via a throttle point 5.

The valve seat 6 tapers in the direction of the bore 4, that is, counter to the inflow direction according to arrow 2, and the valve seat 6 is assigned a locking member 7 which is supported in a stroke-movable manner (arrow 8). The locking member 7 is supported in the exemplary embodiment (FIG. 1) via an actuating movement transmitter 9, which is shown in FIG

Diameter rod-shaped, thin actuating plunger is formed and which is applied and adjustable relative to the control valve 1 to the flow direction according to arrow 2 via a magnetic actuator of the injection injector, not shown here.

In the closed position, the locking member 7 is seated in a seat contact zone 10 on the valve seat 6, to which a bore 11 in the valve plate 3 connects on the low pressure side, into which the locking member 7 supported by the actuating movement transmitter 9 is immersed and which, based on FIGS. 1 and 2, forms part of the low pressure side discharge path which, as in 1 shows, continues in transverse channels 12 which lie between the valve plate 3 and the housing 13 of the control valve 1, the valve plate 3 being centered and fixed against the housing 13 via a clamping ring 14 in the exemplary embodiment.

In connection with the high pressures present on the high-pressure side, very high flow velocities result, based on the opening position of the blocking member 7, not shown, when flowing through the throttle point 5, which can result in cavitation of the flow due to the transfer of the flow medium to the low-pressure side due to the pressure drop , wherein the cavitation bubbles when they hit the locking member 7 and the locally associated deflection and flow delay can implode, which can lead to cavitation erosion at the locking member 7 and valve seat 6.

This is where the invention comes in, as it is explained with reference to FIGS. 3 to 9 below, the same reference numerals being used for the same parts.

FIG. 3 illustrates that the locking member 7, which is designed as a spherical segment in the exemplary embodiments, has a diameter that is matched to the bore 11, such that there is a radial guidance through the bore 11 in the central plane 15 of the locking member 7, which is parallel to the seat contact zone 10 Stroke mobility - according to arrow 8 - of the locking member 7 in the sense of a low-friction sliding guide, but delimits a space 16 downstream of the seat surface 10 due to the guide serving as a gap seal, from which the connection to the low-pressure side follows throttled. This throttled connection is illustrated in FIG. 3 by means of bores 17 which open onto the space 14 adjacent to the valve seat 6 and which run radially to the stroke axis 18 of the actuating motion transmitter 9.

In the transition from the high-pressure side (arrow 2) to the low-pressure side - symbolized in FIG. 3 by the arrows 19 - two throttling points follow one another, so that there is a stepped pressure reduction with a correspondingly lower pressure gradient at the throttling point 5 in the inflow onto the blocking element 7, whereby the conditions with regard to the occurrence of cavitation erosion are significantly mitigated. The axial guide provided for the locking member 7, by means of which the throttle chamber 16 is delimited between the seat surface 10 or throttling point 5 and downstream throttle bores 17, also contributes to the locking member 7 also corresponding to its locking position in its position lifted from the valve seat 6 Centering maintains what to stabilize the flow conditions on the locking member 7 and

Flow conditions with respect to the blocking member 7 contributes and also reduces the mechanical stresses between the blocking member 7 and the valve seat 6 in that deviations in the axial position are at least largely avoided.

The centering guide function for the locking member 7 proves to be expedient if the locking member 7 is firmly connected to the actuating movement transmitter 9 or, without a centering connection to the latter, is only acted upon via the latter. Furthermore, the guide function proves to be expedient in connection with full-spherical locking members, or also locking members designed as a spherical segment, wherein in the exemplary embodiment a spherical segment is provided as a locking member 7. Instead of spherical locking members 7, in particular conical or conical locking members 7 tapering in the direction of the valve seat can also be provided.

FIGS. 5 and 6 represent solutions which functionally correspond to what has been explained with reference to FIGS. 3 and 4. In structural terms, they differ from the solution according to FIGS. 3 and 4 by the way in which the throttle chamber 16 is connected to the low-pressure side via corresponding throttle bores or throttle ducts, throttle ducts 20 being provided in the embodiment according to FIG open out the low-pressure side (arrow 19), in Figure 5 the throttle channels are formed by the fact that a valve plate 21 is provided to which a cover plate 22 is assigned, the valve plate 21 and cover plate 22 forming channels 20 between their mutually facing surfaces, which into the Cover plate 22, are incorporated into the valve plate 21 or in both plates and which run in the parting plane 23 of the two plates. The division plane 23 corresponds to the sectional plane between the bore 11 and the conical valve seat 6, so that the bore 11 runs in the cover plate 22 and the valve seat 6 is incorporated into the valve plate 21. Overall, this leads to a simplified structure. FIG. 6 again assumes a division into valve plate 24 and cover plate 25, as was explained with reference to FIG. 5. The valve seat 26 is also incorporated into the valve plate 24 here, the bore 11 is assigned to the cover plate 25 and passes through it, opening out onto the valve seat 26 within the diameter thereof. Accordingly, the valve seat 26, which widens in the inflow direction according to arrow 2, has a radial overlap region with the cover plate 25, the partial plane between the valve plate 24 and the cover plate 25 being designated 27 and being offset against the inflow direction 2 to the central plane 15 of the blocking member 7, which is axially in the region the bore 11 lies, so that in this solution, too, the guide for the locking member 7 lies in the region of the bore 11, in FIG. 5 in the region of the cover plate 22, in FIG. 6 in the cover plate 25. Because the diameter of the bore 11 is smaller than the diameter of the conical valve seat 26 in the region of the partial plane 27, the throttle chamber 28 is partially covered by the side of the cover plate 25 facing the valve plate 24, so that the cover plate 25 is on the throttle chamber 28 can open axially penetrating throttle bores 30. The invention thus shows a wide variety

Possibilities of connecting the respective throttle chamber 16 or 28 to the low-pressure side, so that corresponding design requirements can be taken into account within the scope of the invention.

A further possibility of the throttling connection to the low-pressure side is shown in FIGS. 7 and 8, with an initial situation also being given here, which corresponds in principle to that according to FIGS. 3 to 6. The valve plate 31, as an inlet on the high-pressure side according to arrow 2, in turn has a bore 4, which opens out centrally via a throttle point 5 onto the valve seat 6, which in the closed position of the blocking member 32 is covered by the latter. In this exemplary embodiment, a ball segment is also provided as the locking member 32, the central plane 15 of which runs parallel to the seat contact surface 10 and which is guided axially displaceably in the region of the central plane 15 and bears sealingly against the wall of the bore 33, which acts as a guide bore for the locking member 32 on the seat surface 6 connects and delimits the throttle space 34 to the seat 6 together with the locking member 32. In this case too, the locking member 32 is supported by an actuating movement transmitter 9 which can be moved in accordance with the arrow 8. As illustrated in FIG. 8, the throttle chamber 34 is connected to the low-pressure side via the circumference of the bore 33 provided axially extending recesses, which are designated by 35 and which extend in the stroke movement direction (arrow 8) on both sides of the central plane 15, such that, analogously to the throttle bores 17 or the throttle ducts 20 or the throttle bores 28, regardless of the respective stroke position the locking member 32 is a throttling connection of the space 34 to the low pressure side. For this purpose, it can be expedient to design the actuating movement transmitter 9, which is designed as a punch or as an actuating rod, with a diameter smaller than the blocking member 32, so that the incorporation of further channels or bores is unnecessary.

Starting from a basic design according to FIGS. 7 and 8, FIGS. 9 and 10 show an embodiment in which, in turn, a locking member 36 designed as a spherical segment is used, which in the region of its central plane 15 parallel to the seat contact zone 10 adjoins the wall of the bore 38, which as Guidance for the locking member 36 is used and compared to and the subsequent valve seat 6, the locking member 36 delimits the throttle space 37. Outflow cross-sections opening toward the low-pressure side are assigned to this, which, as throttle cross-sections, are dependent on the stroke position of the blocking member 36 in the size of their cross-sectional area. These variable throttle cross sections are formed by recesses 40 in the circumference of the throttle bore 39, which can be designed according to the desired throttle behavior. For example, in FIGS. 9 and 10 an embodiment is illustrated in which, in the closed position of the locking member 36, the recesses 40 are at least largely deactivated via the locking member 36 and are only released with an increasing opening stroke.

Within the scope of the invention, there are thus various possibilities for realizing a stepped throttle transition from the high to the low pressure side in control valves of the type described, solutions being created both with regard to cavitation erosions and with regard to the mechanical wear of the locking member and valve seat Improve the life and reliability of the control valve.

Claims

claims

1. Valve design for control valves, in particular for control valves of injection injectors operated with diesel or heavy oil and working with accumulator pressure injection, preferably large-volume internal combustion engines, with one

Valve seat, which is located between a high-pressure inlet and a low-pressure side blocking element, which, in its closed position towards the valve seat tapering in the closing direction via its seat contact zone, is acted upon against the inflow direction by means of a lifting actuator in the direction of its closed position and the high-pressure side in the inlet to the valve seat a choke section is located opposite, characterized in that the blocking member (7; 32; 36), based on the closed position, adjacent to the seat contact zone (10) has a receiving space (16; 28; 39) which is delimited from the low pressure side and is in a throttled connection to the low pressure side ) assigned.

2. Valve design according to claim 1, characterized in that the locking member (7; 32; 36), based on the closed position, in the area adjacent to the seat contact zone (10) in a restricted area against the low pressure side (16; 28; 39) lies.

3. Valve design according to claim 1 or 2, characterized in that the delimitation of the space (16; 28; 39) opposite the seat contact zone (10) by means of a guide for the locking member (7; 32; 36) which is central to the valve seat (6). is formed.

4. Valve design according to one of the preceding claims, characterized in that the locking member (7; 32; 36) forms a component independent of the actuating movement transmitter (9).

5. Valve design according to one of claims 1 to 3, characterized in that the locking member (7; 32; 36) forms a component connected to the actuating movement transmitter (9).

6. Valve design according to one of the preceding claims, characterized in that a valve ball is provided as the blocking member (7; 32; 36).

7. Valve design according to one of claims 1 to 5, characterized in that a ball segment with the actuating movement transmitter (9) associated flat side is provided as the blocking member (7; 32; 36).

8. Valve design according to one of claims 1 to 5, characterized in that a valve body which tapers conically in the closing direction is provided as the blocking member (7; 32; 36).

9. Valve design according to claim 8, characterized in that the valve body ends cylindrically in the opposite direction to its conical taper.

10. Valve design according to one of the preceding claims, characterized in that the valve seat (6; 26) is spherical, in particular spherical, in the region of the seat surface.

11. Valve body according to one of claims 1 to 9, characterized in that the valve seat (6; 26) is conical in the region of the seat surface, in particular as a flat stump.

12. Valve body according to claim 10 or 11, characterized in that a cylindrical guide part (bore 11; 33; 38) is provided as a guide on the valve seat on the low pressure side.

13. Valve design according to claim 12, characterized in that the cylindrical guide part (bore 11; 38) adjoins the surface of the valve seat (6).

14. Valve design according to claim 12, characterized in that the valve seat (26) overlaps the cylindrical guide part (bore 11) radially outwards.

15. Valve formation according to one of claims 12 to 14, characterized characterized in that the guide part (bore 11) is integrally formed with the valve seat (6).

16. Valve seat according to one of claims 12 to 14, characterized in that a valve plate (21) containing the valve seat (6) is assigned a cover plate (22) which contains the guide part (bore 11).

17. Valve design according to one of the preceding claims, characterized in that the space delimited by the guide to the seat contact zone (10) (16) has a radial connection (bore 17; channel 20) to the low pressure side.

18. Valve design according to claim 16 and 17, characterized in that the radial connection is formed by at least one radial throttle channel (20) delimited by valve plate (21) and cover plate (22).

19. Valve arrangement according to claim 17, characterized in that the radial connection is formed by at least one radial throttle bore (17).

20. Valve arrangement according to one of claims 1 to 16, characterized in that _the% delimited by the guide space (16) has an axial connection (bore 28; recess 35; 40) to the low pressure side.

21. Valve arrangement according to claim 20, characterized in that the axial connection is formed by an axial bore (28) offset radially for guidance (bore 11).

22. Valve design according to claim 21, characterized in that the axial bore (28) is provided in the cover plate (25).

23. Valve design according to claim 21, characterized in that the axial connection comprises a recess (35) provided in the circumference of the guide (bore 33).

24. Valve design according to claim 23, characterized in that the axial connection is formed by recesses (35) provided in a regular arrangement in the circumference of the guide (bore 33).

25. Valve design according to claim 20, characterized in that the axial connection is formed by recesses and / or flats provided in the circumference of the area of the locking member assigned to the guide.

26. Valve design according to one of the preceding claims, characterized in that the space delimited by the guide (39) has a throttle connection (recess 40) in cross-section dependent on the stroke of the locking member (36) to the low-pressure side. ^

27. Valve design according to claim 26, characterized in that the cross-section-dependent throttle connection provided by in the circumference of the guide

Recesses (40) is formed.

28. Valve design according to claim 26 or 27, characterized in that the recess (40) has a cross section widening in the stroke direction to the low pressure side.

29. Valve design according to claim 26, characterized in that the cross-section-dependent throttle connection is formed by recesses and / or flats provided in the circumference of the locking member.

30. Valve design according to claim 29, characterized in that the recess widens in cross section in the stroke direction towards the high pressure side.

31. Valve design according to one of claims 23 to 30, characterized in that the recesses which are variable in cross-section in the stroke direction start from a cross-sectional plane lying in the region of the guide cross-section.