EP1690025B1 - Device, method for producing the device, chamber device and transfer device - Google Patents

Description

The invention relates to a device having a first body, which has a recess, and a second body, which is guided into the recess. The invention further relates to a method for manufacturing the device. The invention further relates to a chamber device having a chamber having a chamber housing having a recess with a piston and with the device. The invention further relates to a transmission device which transmits a deflection of an actuator, in particular for an injection valve, with the chamber device.

A transmission device may be arranged in an injection valve of an internal combustion engine and preferably transmits the deflection of an actuator to a nozzle needle. Piezo actuators are increasingly being used as actuators because of their very fast response time to control signals to precisely control the metering of fuel and possibly to enable several successive partial injections during a working cycle of a cylinder of the internal combustion engine.

The fuel pressure in an injector for diesel engines is up to 2,000 bar. This has the consequence that considerable forces must be applied to open or close the nozzle needle. Furthermore, a trained as a piezo actuator actuator only has a much lower stroke than the required stroke of the nozzle needle. For transmitting the stroke of the actuator, it is known to provide a transmitter device, which optionally amplifies the stroke and / or also creates a temperature-induced length compensation.

From the DE 199 50 760 For example, a fuel injection valve is known which has a piezoelectric or magnetostrictive actuator. Between the actuator and a valve needle, a transmission device with two mutually movable reciprocating piston is provided. The transmitter device is hermetically sealed against a valve interior. The first reciprocating piston is operatively connected to the actuator and has a hollow cylindrical shape which is open on one side and whose opening is arranged facing away from the actuator. In the cylinder opening of the second piston is guided. The first reciprocating piston is again in a hollow cylindrical housing. Between an end surface of the housing and the first and the second piston, a transmission chamber is formed. Further, a tension spring is provided which biases the first and second pistons in the opposite direction. Furthermore, a compensation chamber is provided, which is partially bounded by a corrugated tube and is hydraulically coupled to the transmission chamber. The compensation chamber serves to compensate for a change in volume of the transmission chamber and to provide the transmission chamber with a transfer medium with a fixed pressure. However, such a corrugated tube is relatively complicated and expensive.

Also from the DE 101 62 045 A1 For example, a transmission device for transmitting the deflection of a piezoelectric actuator of an injection valve is known. The actuator acts on a first reciprocating piston 1, which is formed in a partial area in the shape of a cylindrical pot and in the pot interior of a second piston engages, which is coupled to a servo valve or a nozzle needle of the injection valve. The first reciprocating piston is guided in a cylinder body. Likewise, the second piston is guided in the cylinder body. The first and second reciprocating pistons are coupled via a pressure chamber. An axial deflection of the first piston is transmitted by means of the pressure chamber in an opposite axial deflection of the second piston. Furthermore, a compensation chamber is provided, which compensates for a change in volume in the transmission chamber and supplies the transmission chamber with a transfer medium with a predetermined pressure. US 4,813,601 describes a transmission device according to the preamble of claim 1. In the US 4,813,601 a piezo control valve, in particular for controlling the fuel injection via an injection valve is described, which consists of a housing arranged in a piezo actuator and a valve. By a hydraulic lash adjuster within the control valve on the one hand possible changes in length of the reference frame are automatically compensated as a result of piezoceramic setting operations in the piezo actuator, so that the same stroke of the piezo actuator is always guaranteed a same stroke on the valve and where further by a hydraulic Hubübersetzung within the control valve on the other a valve lift corresponding to a multiple of the working stroke is achieved.

The object of the invention is to provide a device, a method for manufacturing the device, a chamber device and a transmission device that are simple and that have a long service life.

The object is solved by the features of the independent claim. Advantageous embodiments of the invention are characterized in the subclaims.

According to the invention, a transmission device for an injection valve is specified, which transmits a deflection of an actuator and has a chamber device.

The transfer device has a chamber device. The chamber device comprises a chamber having a chamber housing having a recess, a piston and a device. The device has a first body having a recess and a second body guided into the recess and an elastomer interposed between the two first and second body is introduced into the recess and thus closes and seals the gap between the first and second body in this area. The elastomer has a first groove extending at least partially along the recess spaced from the wall of the recess. The invention thus uses the surprising finding that extends through the groove, the durability of the device significantly, even if the elastomer is exposed to high pressure fluctuations, as by the groove, a contact force is generated, which acts from the groove towards the wall of the recess and Thus, the elastomer presses against the recess and thus enhances the sealing effect.

If the first groove is formed circumferentially, then a particularly uniform tightness along the entire recess is easily ensured.

It when the first groove is guided at a distance of 0.2 to 1.5 mm to the wall of the recess is particularly advantageous. Then the sealing effect is particularly good.

There is provided a second groove extending radially within the first groove. As a result, the sealing effect towards the second body can be significantly improved in particular. Advantageously, the second groove is spaced 0.2 to 1.5 mm apart from the second elastomeric body. This results in a particularly good sealing effect between the elastomer and the second body.

The first groove is deeper than the second groove. As a result, overall, the sealing effect can be significantly improved, which is based on the knowledge that sealing problems occur to a greater extent on the wall of the recess. It is particularly advantageous if the second groove is so wide that it opens into the first groove. This has the advantage that the device can be made very easily since the tool for making the contour of the elastomer can be easily removed from the mold.

The areas of the first and second body where the elastomer comes to rest are free of edges. Possible cross-sectional changes are rounded. This has the advantage that a primer applied to the first body and the second body to ensure a good bond between the elastomer and the first and second bodies, respectively, are simply applied with uniform thickness to the first and second bodies can.

Furthermore, it is advantageous if the first and second bodies are tubular. They are then suitable for insertion into further bodies and can then be permanently connected to them, for example by means of a welded connection. Thus, simply the device can be manufactured separately and used for example for a chamber device.

In a chamber device, the chamber housing is the first body and / or the piston is the second body.

Another chamber device is characterized by a chamber having a chamber housing having a recess with a piston and the device, wherein the first and second body are tubular and the chamber housing with the first body and the piston with the second body are connected. This compound is particularly advantageously produced by welding.

The transmission device has a housing which has a first recess in which a first and a second piston are movably mounted. The first and the second piston are operatively connected via at least one transmission chamber via a fluid, wherein the operative connection causes a displacement of the second piston when the first piston is moved and vice versa, wherein the transmission chamber via a Sealing gap is hydraulically connected to a compensation chamber, the pressure differences between the transfer chamber and the compensation chamber delayed compensated. The chamber of the chamber device, the compensation chamber, the chamber housing the housing and the piston are the first piston. This has the advantage that the elastomer can be produced inexpensively and thus the compensation chamber is overall inexpensive to produce.

In a method of manufacturing the device, the first body and the second body are plasma activated, then the first body and the second body are provided with an adhesion promoter in the areas where the elastomer is to abut, and then the elastomer is introduced and vulcanized. By the plasma activation, which is preferably carried out by means of an ionized gas, for example oxygen, are generated at the areas of the first and second body, where the elastomer is to rest, radicals that are very easy to bond and thus to a very good bond of the adhesion promoter the areas of the first and second body lead. As a result, a very good connection between the first and second body and the elastomer is made possible in a simple manner. The compound is particularly good if the bonding agent is applied very evenly to the first and second body, which is simply there
can be supported by, if the areas of the first and second body, where the elastomer comes to rest, are free of edges.

Figur 1

ein Einspritzventil,

Figur 2

eine erste Ausführungsform einer Übertragungsvorrichtung,

Figur 3

eine zweite Ausführungsform der Übertragungsvorrichtung,

Figur 4

eine Vorrichtung,

Figur 5

eine Draufsicht auf die Vorrichtung gemäß Figur 4,

Figur 6

eine Draufsicht auf eine weitere Ausführungsform der Vorrichtung und

Figur 7

eine Draufsicht auf eine weitere Ausführungsform der Vorrichtung.

Embodiments of the invention are explained below with reference to the schematic drawings. Show it:

FIG. 1

an injection valve,

FIG. 2

A first embodiment of a transmission device

FIG. 3

a second embodiment of the transmission device,

FIG. 4

a device

FIG. 5

a plan view of the device according to FIG. 4 .

FIG. 6

a plan view of a further embodiment of the device and

FIG. 7

a plan view of a further embodiment of the device.

Elements of the same construction and function are identified across the figures with the same reference numerals.

An injection valve 1 has an actuator 2, which is connected via a transmission device 3 with a nozzle needle 4 in operative connection. The actuator 2 is preferred as a piezoelectric actuator educated. However, it may be another actuator producing a stroke. The transmission device 3 preferably translates the deflection of the actuator 2 in the direction of the nozzle needle such that a deflection of the actuator 2 in the direction of the nozzle needle 4 is transmitted to an enlarged deflection of the nozzle needle 4. Furthermore, it preferably also compensates for temperature-induced changes in length of the actuator. The nozzle needle 4 closes or releases depending on their position, a nozzle 41 in the injection valve 1 and thus controls the metering of fuel.

Depending on the embodiment, the transmitter device 3 can also transmit a deflection of the actuator 2 in the direction of the nozzle needle 4 in the opposite direction to the nozzle needle 4.

The transmission device 3 has a first piston 6, which has a ring-cylindrical shape open on one side. The ring-cylindrical part of the first piston 6 defines a first transmission chamber 10 into which a second piston 7 is guided. The first piston 6 is inserted into a cup-shaped recess 8 of the housing 5 and guided there. The second piston 7 is guided in a further recess 16 of the housing 5 and projects into a recess 9 of the first piston 6.

The second piston 7 has an annular shoulder, on which its diameter increases in an abrupt manner toward the region which is guided in the first piston 6. The shoulder forms an annular rear surface 13 of the second piston 7. A first end surface 17 of the first piston, the rear surface 13 of the second piston and the end surface 15 of the housing 5 define a second transmission chamber 11.

The second transmission chamber 11 is hydraulically connected to the first transmission chamber 10 via a first sealing gap 18, which is formed between a side wall of the second piston 7 and an inner wall of the first piston 6. The first transmission chamber 10 is from a second end face 19th of the first piston 6 and an end face 20 of the second piston 7 is limited.

The first sealing gap 18 is designed so narrow that short-term pressure fluctuations between the transformer chambers 10, 11 are not compensated. Furthermore, the second transmission chamber 11 is connected to a compensation chamber 22 via a second sealing gap 21, which is formed between the outer wall of the first piston and the inner wall of the housing. The first transmission chamber 10 is hydraulically coupled via a bore 60, which is introduced into the first piston 6, with the compensation chamber 22. The compensation chamber 22 is bounded by a rear surface 14 of the first piston and by a device which is described in detail with reference to FIG FIG. 4 is described.

The device comprises in the embodiment of the transmitter device according to FIG. 2 a first sleeve 52 and a second sleeve 53 having a smaller diameter than the first sleeve 52. Between the first and second sleeve 52, 53 an elastomer 50 is introduced. The first sleeve 52 is fixedly connected to the housing 4, preferably by welding. The second sleeve 53 is fixedly connected to the first piston 6, preferably also by welding.

In a second embodiment of the transmitter device ( FIG. 3 ), the elastomer 50 is introduced into the space between the first piston 6 and the end portion of the housing 5. The embodiment according to FIG. 2 offers the advantage that the first and second sleeves 52, 53 and the elastomer can be prepared in advance. The elastomer 50 is intended to allow an increase in the volume of the compensation chamber 22 by its elastic properties and thus avoid excessive pressure increases.

The first and second transfer chambers 10, 11 and the compensation chamber 22 are filled with a fluid, preferably oil. The housing 5, the first piston 6 and the second piston 7 and also the first and second sleeves 52, 53 are preferably made of steel. Preferably, a tensioning means 54, which is preferably designed as a spiral spring, provided that on the one hand supported on a stop ring 55 and on the other hand acts on the elastomer 50. The tensioning means is biased to bias the elastomer 50 toward the balance chamber 22 with a predetermined force.

In FIG. 4 For example, the device is provided with a first body formed as a first sleeve 52 with a second body formed as a second sleeve 53 and the elastomer 50. The first body is in accordance with the embodiment of the transmitter device 3 FIG. 3 the housing 5 and the second body is the first piston 6.

The elastomer 50 is introduced into the intermediate region between the first sleeve 52 and the second sleeve 53 in such a way that it closes and seals it. In the elastomer 50, a first groove 61 is formed, which extends at a distance from the wall of the recess along the recess. It is, as in the top view in FIG. 5 represented, circumferentially within the recess of the first sleeve 52, ie the area enclosed by the sleeve 52 in the interior. It is preferably spaced from the wall of the first sleeve with a distance of 0.2 to 1.5 mm relative to the groove center. The depth of the first groove is preferably selected between 0.2 and 1.5 mm. By the groove causes compressive forces, which are caused by a relative movement of the first piston 6 to the second piston 7, also act radially on the elastomer and thus press the elastomer against the wall of the first sleeve 52 and thus significantly increase its sealing effect.

Further, a second groove 62 is provided, the up-running edge preferably between 0.2 and 1.5 mm to the second sleeve 53 is spaced. It is ensured by the second groove 62 that the pressure prevailing in the compensation chamber 22 also acts radially on the second sleeve 53 and thus presses the elastomer 50 against the second sleeve 53. As a result, the sealing effect with respect to the second sleeve 53 is also significantly improved.

Preferably, the second groove 62 is formed less deep than the first groove 61. This is based on the knowledge that even a less deep second groove is sufficient to ensure sufficient tightness of the elastomer 50 to the second sleeve 53 in contrast to the first sleeve 52. In addition, the smallest possible depth of the grooves 61, 62 desirable in terms of minimizing the volume of the compensation chamber 22. The fact that the second groove 62 opens directly into the first groove 61, a simpler demolding of the tool is possible with the the elastomer is brought into its shape, which makes the device much easier to manufacture, especially with regard to very small dimensions.

For producing the device according to FIG. 4 the first body formed as a first sleeve 52 and the second body formed as a second sleeve 53 is plasma-activated. This is preferably done by rinsing with ionized gas, eg oxygen, whereby radical sites are formed on the metal surface, which result in a very strong bondability of the surface of the first and second sleeves 52, 53. Subsequently, a bonding agent is applied to the first and second sleeve, preferably in the region in which the elastomer 50 is intended to abut. The effect of the primer is better the thinner the layer provided with the primer. Ideally, this is a monomolecular layer.

The rounded edges of the first and second sleeves 52, 53 ensure that the bonding agent is easy can distribute evenly. Experiments have shown that too sharp edges can lead to an uneven distribution of the adhesion promoter and thus to local changes in layer thickness, with the result that in the thicker regions of the adhesion promoter, the elastomer does not adhere so well to the first and second sleeves 52, 53 and thus leaks can occur.

In a next production step, the first and second sleeves 52, 53 are inserted into a corresponding molding tool and then the elastomer composition is injected and permanently brought into its shape by means of a vulcanization process.

Another embodiment of the device is based on FIG. 6 shown. Instead of the ring shape, the tubular body of the first body is formed here in a rectangular basic shape. Alternatively, however, the first and second bodies can also be formed in further tube shapes, such as an elliptical basic shape.

The first groove 61 is not circumferentially formed in this embodiment, but only in sections, preferably in areas where an additional radial contact pressure of the elastomer 50 is necessary to ensure the desired sealing effect and durability of the device.

In a further alternative embodiment of the device, the first groove 61 is formed so wide in the radial direction that sufficient forces are exerted on this wall via its facing to the first sleeve 52 wall forces to ensure the tightness with respect to the first sleeve 52 and at the same time over the wall, which faces the second sleeve 53, sufficient contact forces are transmitted, which ensure a sufficient tightness with respect to the second sleeve 53. The device according to FIG. 4 . 5, 6 and 7 can be used except for a transmitter device 3 for any other chamber device.

LIST OF REFERENCE NUMBERS

1

Injector

2

actuator

3

transmission device

4

nozzle needle

5

casing

6

first piston

7

second piston

8th

Recess of the housing

9

Recess in the first piston

10

first transformer chamber

11

wide transformer chamber

13

Rear surface of the second piston

15

End face of the housing

16

further recess in the housing

17

first face of 1st piston

18

first sealing gap

19

second end face of the 1st piston

20

Face of the 2nd piston

21

second sealing gap

22

compensation chamber

23

Rear surface of the first piston

50

elastomer

51

piston rod

52

first sleeve

53

second sleeve

54

Clamping means / helical spring

55

stop ring

56

transmission means

57

protective layer

59

graduated implementation

60

drilling

61

first groove

62

second groove

Claims (13)

1. Transmission device for an injection valve (1), which transmission device transmits a deflection of an actuator (2), having a housing (5) which has a first recess in which a first and second piston (6, 7) are mounted in movable fashion, and the first and the second piston (6, 7) are operatively connected by means of a fluid via at least one transmitter chamber (10, 11), wherein the operative connection effects a displacement of the second piston (7) when the first piston (6) is moved and vice versa, wherein the transmitter chamber (10, 11) is hydraulically connected via a sealing gap (21) to an equalization chamber (22), which sealing gap compensates pressure differences between the transmitter chamber (10, 11) and the equalization chamber (22) with a delay, and having a chamber device with a chamber which has a chamber housing which has a recess, with a piston and with a device, which has the following features: a first body, which has a recess, a second body, which is inserted into the recess, and an elastomer, which is introduced between the first and second body into the recess and thus closes and seals off, in said region, the intermediate space between the first and the second body, wherein the elastomer (50) has a first groove (61) which extends, spaced apart from the wall of the recess, at least partially along the recess, wherein the regions of the first and second body against which the elastomer bears are free from edges, and wherein the chamber is the equalization chamber (22), the chamber housing is the housing (5) and the piston is the first piston (6),
   characterized
   in that a second groove (62) is formed in the elastomer (50), which second groove runs radially within the first groove,
   and in that first groove (61) is deeper than the second groove (62).
2. Transmission device according to the preceding claim, wherein the first piston (6) has the form of a ring-shaped cylinder which is open on one side and which delimits the transmitter chamber (10) and in which the second piston (7) is guided, such that the transmitter chamber (10) is delimited by a face surface (19) of the first piston (6) and a face surface (20) of the second piston (7).
3. Transmission device according to the preceding claim, wherein the equalization chamber (22) is delimited by a rear surface (14) of the first piston (6) and the chamber device.
4. Transmission device according to one of the preceding Claims 2 or 3, wherein the second piston (7) has a ring-shaped shoulder at which its diameter abruptly increases and which forms a ring-shaped rear surface (13), and wherein a face surface (17) of the first piston (6), the ring-shaped rear surface (13) of the second piston (7) and an end surface (15) of the housing (5) delimit a second transmitter chamber (11).
5. Transmission device according to the preceding claim, wherein the second transmitter chamber (11) is hydraulically connected to the transmitter chamber (10) via a first sealing gap (18) which is formed between a side wall of the second piston (7) and an inner wall of the first piston (6),
   and wherein the second transmitter chamber (11) is connected to the equalization chamber (22) via a second sealing gap (21) which is formed between an outer wall of the first piston (6) and an inner wall of the housing (5).
6. Transmission device according to one of the preceding claims,
   characterized in that
   the first groove (61) is formed in encircling fashion within the recess.
7. Transmission device according to one of the preceding claims,
   characterized in that
   the first groove is spaced apart from the wall of the recess of the first body by 0.2 to 1.5 mm.
8. Transmission device according to one of the preceding claims,
   characterized in that
   the second groove is spaced apart from the abutment of the elastomer (50) against the second body by 0.2 to 1.5 mm.
9. Transmission device according to one of the preceding claims,
   characterized in that
   the second groove (62) is of such a width that it opens into the first groove (61).
10. Transmission device according to one of the preceding claims,
    characterized in that
    the first and second bodies are of tubular form.
11. Transmission device according to one of the preceding claims,
    characterized in that
    the chamber housing is the first body and/or the piston is the second body.
12. Transmission device according to Claim 10, characterized in that
    the chamber housing is connected to the first body and the piston is connected to the second body.
13. Transmission device according to the preceding claim,
    characterized in that
    the chamber housing is welded to the first body and the piston is welded to the second body.

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