WO2007057255A1

WO2007057255A1 - Non-return valve and injector having a hydraulic transformer

Info

Publication number: WO2007057255A1
Application number: PCT/EP2006/067175
Authority: WO
Inventors: Juergen Frasch; Christoph Butscher; Stephan Wehr
Original assignee: Robert Bosch Gmbh
Priority date: 2005-11-21
Filing date: 2006-10-09
Publication date: 2007-05-24
Also published as: DE102005055360A1

Abstract

A non-return valve is proposed, the service life and operational reliability of which are increased considerably in comparison with conventional non-return valves having a spherical valve element. The valve element is configured as a sleeve (7) which is guided axially in a bore (3). In an alternative exemplary embodiment (figure 4), the valve element (43) is of spherical configuration and the stroke stop (45) is of sleeve-shaped configuration.

Description

Check valve and injector with hydraulic translator

State of the art

The invention relates to a check valve with a valve member, with a valve seat and with a

Valve spring, wherein the valve spring at one end bears against the valve member and the other end against an abutment.

Such check valves, in which the valve member is formed as a ball, are well known from the prior art.

These check valves are suitable for many applications, however, there are in particular in use in injectors with hydraulic pressure booster, as in modern fuel injection systems for

Internal combustion engines are used, application trap in which the conventional check valves have proven to be unsustainable enough.

The object of the invention is to provide non-return valves which can be used even at extremely high pressures and whose service life is high even at high switching frequencies.

This task is performed at a check valve after the The preamble of claim 1 achieved in that the valve member is formed as a sleeve, that the sleeve is guided axially displaceably in a bore, and that the sleeve has a cooperating with the valve seat tip.

Advantages of the invention

Unlike the known from the prior art spherical valve member according to the invention

Valve member axially slidably guided in a bore, so that the valve member can not escape laterally and always impinges on the same position of the valve seat on this, when it moves into the closed position. This achieves a very good seal and at the same time reduces wear.

In conventional check valves, the lateral deflection of the valve member in the open position of the check valve causes only when the impact

Valve member on the valve seat, the valve member is centered by the valve seat again. This leads to a relative movement between the valve member and the valve seat. This relative movement causes wear and significantly shortens the life of the valve seat and valve member.

It has proven to be advantageous if a dome of the valve member is formed dome-shaped and / or conical. Due to the dome-shaped design of the dome, the advantages of a spherical valve member can also be used in the check valve according to the invention.

In a further advantageous addition of the invention it is provided that at the end remote from the tip of the Sleeve, a blind hole is provided, which serves to receive the valve spring. As a result, the valve spring is fixed in the radial direction and can not move laterally. This measure significantly increases the service life of the valve spring in the non-return valve according to the invention.

It has proved to be particularly advantageous if the blind hole receives one end of the valve spring in the radial direction without play. This can not be

Relative movement between the end of the valve spring and the blind hole or the sleeve of the valve member occur. As a result, no wear between the end of the valve spring and the valve member can occur.

In order to enable the fastest possible opening of the non-return valve according to the invention, advantageously at least one connecting bore arranged in the direction of flow downstream of the crest is provided which connects a reduced-diameter portion of the sleeve to the blind hole.

Alternatively, it is also possible that the sleeve has at least one longitudinal groove which extends over the entire length of the sleeve. By means of the at least one longitudinal groove, fuel can flow past the sleeve past the check valve according to the invention when the non-return valve is open.

Advantageously, it is also provided that an abutment of the valve spring has a recess, and that the recess receives one end of the valve spring in the radial direction without play. As a result, the above-mentioned advantages of a play-free recording of the valve spring can also be realized on the abutment. At the same time it is advantageous to form the abutment as a stroke stop. This can be ensured that the valve spring is only printed together by a certain amount when the valve member lifts from the valve seat. By limiting the travel by means of the stroke stop thus the stress of the valve spring is reduced during operation and limited, which increases their life.

In order to set the desired opening stroke, the abutment is fixed in the bore in the axial direction. This can for example take place in that a circumferential groove is formed in the bore, and in that a snap ring or a snap ring is provided in the circumferential groove, which fixes the abutment in the axial direction. Alternatively, it is also possible to peg or weld the abutment with the component which receives the valve member, in particular a pressure interrupter piston of a hydraulic translator of an injector.

The object mentioned is inventively solved even with a check valve with a spherical valve member and with a stroke stop that the stroke stop is designed as a sleeve, that the stroke stop has a long bore, and that a diameter of the longitudinal bore of the stroke stop is smaller than a diameter of the valve member is.

Characterized in that the valve member in the open state of the elongated bore of the stroke stop, which can be chamfered of course, is centered, the valve member of the inventive non-return valve meets exactly centered on the valve seat when the check valve closes again, so that a significant wear between the valve seat and valve member is not detectable. Furthermore can be dispensed with in this embodiment, a valve spring, which significantly reduces the manufacturing cost and space requirements of the check valve according to the invention. Due to the reduced masses, this check valve responds very quickly.

To adjust the stroke of the valve member, the stroke stop is advantageously fixed in the bore in the axial direction.

In order to pass the fuel past the valve member and the stroke stop when the valve member is open, a connecting bore is provided on the stroke stop, which connects at least one diameter-reduced portion of the stroke stop to the longitudinal bore. Alternatively, it is also possible that longitudinal grooves are provided which extend over the entire length of the sleeve.

The check valve according to the invention can be used particularly advantageously in an injector with a hydraulic pressure booster for an internal combustion engine.

Further advantages and advantageous embodiments of the invention are the following drawings, whose

Description and claims removed. All features described in the drawings, the description in the claims can be essential to the invention both individually and in any combination.

drawings

Show it Figure 1 is a longitudinal section through a first

Embodiment of a check valve according to the invention,

2 shows a second embodiment of a check valve according to the invention,

FIG. 3 shows a third exemplary embodiment of a check valve according to the invention,

Figure 4 shows a fourth embodiment of a check valve according to the invention, and

Figure 5 shows an injector according to the invention with hydraulic pressure booster and check valve according to the invention.

Description of the embodiments

In FIG. 1, a component, which can be, for example, a pressure booster piston of a hydraulic pressure booster, is designated by the reference numeral 1. In this component 1, a stepped bore 3 is provided. Between two sections of the bore 3 with different diameters, a valve seat 5 is formed.

In the bore 3, a valve member in the form of a cylindrical sleeve 7 is guided axially displaceable. At the left in Figure 1 end of the sleeve 7, a dome 9 is formed, whose outer contour is dome-shaped. The dome-shaped outer contour of the dome 9 cooperates with the valve seat 5 in the component 1 and closes the check valve as soon as the sleeve 7 rests on the valve seat 5. In the sleeve 7, a blind hole 11 is provided, which is designed as a stepped bore. At one shoulder 13 of the blind bore 11 at one end a valve spring 15 is supported. Where the valve spring 15 is supported on the shoulder 13, the diameter of the blind hole 11 is dimensioned so that the valve spring 15 is fixed without play in the blind hole 11. As a result, relative movements between the valve spring 15 and the sleeve 7 are prevented.

At the end of the sleeve 7 facing away from the dome 9, the blind bore 11 has a slightly larger diameter than the valve spring 15, so that the valve spring 15 does not bear against the wall of the blind bore 11 in the opened state of the check valve.

Thus, when the check valve is open, that is, when the sleeve 7 is lifted from the valve seat 5 position, fuel or other liquid medium through the

Can flow check valve, two structural configurations in Figure 1, which can be used alternatively shown.

In the part of the sleeve 7, which is located above the central axis, a connecting bore 17 is shown, which connects a diameter-reduced region 19, which lies downstream of the tip 9 in the flow direction, with the blind hole 11. If necessary, a plurality of connecting bores 17 can be provided over the circumference of the sleeve 7.

In the part of the sleeve 7, which is located below the central axis, an alternative embodiment is shown. In this embodiment, instead of Connecting bore 17 a longitudinal groove 21 is shown, which extends from the reduced diameter portion 19 to the opposite end of the sleeve 7. Of course, it is also possible in this embodiment and advantageous in many cases, if several

Longitudinal grooves 21 are uniformly distributed over the circumference provided in the sleeve 7.

The right in Figure 1 end of the valve spring 15 is supported in an abutment 23. In the abutment 23, a recess 25 is provided, whose diameter is matched to the diameter of the valve spring 15, that this end of the valve spring 15 is fixed without play in the radial direction. As a result, it is also not possible at the right end of the valve spring 15 in FIG

Relative movements between the valve spring 15 and the abutment 23 come. As a result, occurs at this end of the valve spring 15 no mechanical wear.

In the center of the abutment 23, a bore 27 is provided through which the fuel can flow when the check valve is open. The diameter of the bore 27 may, if desired, be chosen so that the movements of the valve member 7 are damped.

The abutment 23 is fixed in the first embodiment shown in Figure 1 by means of a snap ring 29 which is inserted into a circumferential groove 31 in the axial direction in the bore 3. If, as shown in Figure 1, the contact surface between the abutment 23 and the snap ring 29 is frustoconical, the force exerted by the valve spring 15 on the abutment 23 force causes the snap ring 29 is pressed into the circumferential groove 31 and thus the snap ring 29 is secured in the circumferential groove 31. In order to limit the deformation and thus also the mechanical load of the valve spring 15, the abutment 23 is also designed as a stroke stop for the sleeve 7 at the same time. The maximum possible stroke is shown in Figure 1 by the reference numeral 33. As soon as the tip 9 facing away from the end of the sleeve 7 comes to rest on the abutment 23, the maximum stroke is reached. As a result, the mechanical stress of the valve spring 15 is limited.

FIG. 2 shows a second exemplary embodiment of a check valve according to the invention. The same components are provided with the same reference numerals, and the same applies with regard to FIG. 1. The main difference between the first

Embodiment and the second embodiment is that in the embodiment of Figure 2, the abutment 23 is fixed by means of a pin 35 in the bore 3 in the axial direction. In this embodiment, a longitudinal groove 37 is provided instead of the bore 27.

In the embodiment according to FIG. 3, the abutment 23 is fixed in the axial direction in the bore 3 in that a welding ring 39 against which the

Abutment 23 is supported welded to the housing 1. The weld is provided in Figure 3 by the reference numeral 41.

FIG. 4 shows a further exemplary embodiment of a check valve according to the invention. Again, it is true that the same components provided with the same reference numerals and reference is made to the above. In this embodiment, the valve member is formed as a ball 43. A valve spring is not provided and not required.

In this embodiment, a sleeve-shaped

Stroke stop 45 is fixed with a longitudinal bore 47 in the bore 3 in the axial direction by means of a snap ring 31. The diameter of the longitudinal bore 47 is smaller than the diameter of the spherical valve member 43. The maximum stroke is also indicated in this embodiment by the reference numeral 33.

When the return valve is open, the longitudinal bore 47 is closed by the valve member 43. So that fuel can nevertheless flow through the check valve as soon as the valve member 43 has lifted off the valve seat 5, the stroke stop 45 has a diameter-reduced region 51. From the diameter-reduced portions 51 go from a plurality of connecting holes 53, which open into the longitudinal bore 47. As a result, the fuel can flow past the valve member 43, which in the open state (not shown) bears against the stroke stop 45.

The attachment and fixation of the stroke stop 45 in the bore 3 can in the same way as with reference to

Embodiments described in accordance with Figure 3 in connection with the abutment 23, take place.

5 shows an application example of the check valve according to the invention is shown schematically. An injector is designated in its entirety by the reference numeral 55. The injector 55 is supplied via a high-pressure line (without reference numeral) from a common rail 57 with high-pressure fuel. In the injector 55 is a hydraulic pressure booster 59th intended. The hydraulic pressure booster 59 comprises a converter piston 61, which separates a low-pressure space 63 from a high-pressure space 65. In the Druckubersetzerkolben 61 a long hole 3 is present. In the bore 3 a stylized return check valve 67 is arranged, which prevents fuel from the high-pressure chamber 65 can flow into the low-pressure chamber 63. This non-return valve 67 is preferably a non-return valve according to the exemplary embodiments according to FIGS. 1 to 4.

The high-pressure chamber 65 is hydraulically connected to a pressure chamber 69 in which a nozzle needle 71 is arranged. Via a first solenoid valve 73, which is designed as a 3/2-way valve and controls the hydraulic pressure booster 59, and a second solenoid valve 75, which controls the pressure in the pressure chamber 69, the nozzle needle 71 is opened and closed.

Claims

claims

1. Check valve with a valve member, with a valve seat (5), and with a valve spring (15), wherein the valve spring (15) at one end against the valve member and the other end against an abutment (23) is supported, characterized in that the valve member as Sleeve (7) is formed, that the sleeve (7) in a bore (3) is guided axially displaceable, and that the sleeve (7) has a with the valve seat (5) cooperating tip (9).

2. Check valve according to one of the preceding claims, characterized in that the dome (9) is dome-shaped and / or truncated cone-shaped.

3. Check valve according to one of the preceding claims, characterized in that at the tip (9) facing away from the end of the sleeve (7) has a blind hole (11) is provided, and that the blind hole (11) for receiving the valve spring (15) ,

4. Check valve according to claim 3, characterized in that in the blind hole (11) has a shoulder (13) for supporting the valve spring (15) is provided.

5. Check valve according to one of claims 3 or 4, characterized in that the blind hole (11) a End of the valve spring (15) receives in the radial direction without play.

6. Check valve according to one of claims 3 to 5, characterized in that the sleeve (7) at least one downstream of the dome (7) arranged in the flow direction

Connecting bore (17), and that the at least one connecting bore (17) connects a reduced diameter portion (19) of the sleeve (7) with the blind hole (11).

7. Check valve according to one of claims 3 to 5, characterized in that the sleeve (7) has at least one longitudinal groove (21).

8. Check valve according to one of the preceding claims, characterized in that the abutment (23) has a recess (25), and that the recess (25) receives one end of the valve spring (15) in the radial direction without play.

9. Check valve according to one of the preceding claims, characterized in that the abutment (23) is designed as a stroke stop.

10. Check valve according to one of the preceding claims, characterized in that the abutment (23) is fixed in the bore (3) in the axial direction.

11. A check valve according to claim 10, characterized in that in the bore (3) has a circumferential groove (31) is formed, that in the circumferential groove (29) a snap ring (29) or a snap ring is provided, and that the snap ring (29) or the Seeger ring fixed the abutment (23) in the axial direction.

12. Check valve according to claim 10, characterized in that the abutment (23) with a component (1), which receives the valve member (7), in particular a pressure booster piston (61), pinned or welded.

13. Check valve, with a bore (3), wherein in the bore (3) a valve seat (5) is formed, with a spherical valve member (43) and with a stroke stop (45), characterized in that the stroke stop (45) is formed as a sleeve, that the stroke stop (45) in the bore (3) is axially fixed, that the stroke stop (45) has a longitudinal bore (47), and that a diameter of the longitudinal bore (47) of the stroke stop (45) is smaller than a diameter of the valve member (43).

14. Check valve according to one of the preceding claims, characterized in that the stroke stop (45) in the bore (3) is fixed in the axial direction.

15. Check valve according to claim 14, characterized in that in the bore (3) has a circumferential groove

(29) is formed such that in the circumferential groove (29) a snap ring (31) or the snap ring fixes the stroke stop (45) in the axial direction.

16, check valve according to claim 14, characterized in that the stroke stop (45) with a component which receives the valve member (43), in particular a pressure booster piston (61), pinned or welded.

17. Check valve according to one of claims 15 to 18, characterized in that the stroke stop (45) has at least one connecting bore (53), and that the at least one connecting bore (53) has a reduced diameter portion (51) of the stroke stop (45) with the Longitudinal bore (47) connects.

18. check valve according to one of claims 15 to 18, characterized in that the stroke stop (45) has at least one longitudinal groove.

19. Injector for a fuel injection system of an internal combustion engine, comprising a hydraulic pressure booster (59), characterized in that in the hydraulic pressure booster (59), in particular in a translator piston (61) of the hydraulic pressure booster (59), a check valve (67) after a of the preceding claims is present.