Fluid handling – Removable valve head and seat unit – Threaded into valve casing
Reexamination Certificate
2000-04-24
2001-09-18
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Removable valve head and seat unit
Threaded into valve casing
C137S625650, C137S625680
Reexamination Certificate
active
06289921
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is based on a hydraulic valve that in particular is used for controlling a camshaft movement in a motor vehicle and that includes a valve bushing that is insertable from an end face thereof into the receiving bore of a housing and that has an axially extending control bore into which a disk is inserted from the end face.
Known from DE 41 31 384 C2 is a hydraulic valve that comprises a valve bushing, one face of which is insertable into a receiving bore of a housing. The housing can be, e.g., the housing of an internal combustion engine. Disposed in an axial control bore of the valve bushing is a piston valve with which the pressure medium paths between a supply channel, a discharge channel, and a consumer channel are controllable. One of these channels can branch off axially from the receiving bore of the housing and be disposed with the mouth of the control bore at the face of the valve bushing in the same flow path. In the valve in accordance with DE 41 31 384 C2, the valve bushing is assembled with an electromagnet, by means of which a piston valve is displaceable in the control bore of the valve bushing closer toward the face of the valve bushing against the force of a helical compression spring. The helical compression spring is supported on an internal shoulder of the valve bushing and on a retaining ring that is attached to the piston valve in the vicinity of the end of the piston valve that faces the electromagnet.
A hydraulic valve with a similar structure is known from DE 44 22 742 A1. In this case, a piston valve is displaceable in the control bore of a valve component that is not embodied as a valve bushing to be used in a housing, but rather is itself a housing with external connections. The helical compression spring, against the force of which the piston valve is movable by an electromagnet, is supported between the piston valve and a disk that is pressed into the control bore at a side of the housing that faces away from the electromagnet. In this case it is possible to adjust the spring resistance in that the disk is pressed into the control bore for more or less of the path.
In the valve in accordance with DE 44 22 742 A1, which is produced in series for the automobile industry, the valve housing, piston valve, and support disk for the helical compression spring are manufactured from aluminum or an aluminum alloy.
A hydraulic valve with the features initially described is known from EP 0667 459 A1. In the hydraulic valve illustrated therein, the disk is screwed into the valve bushing, wherein nothing further is required to adjust the force of the helical compression spring fixed between the disk and the piston valve. However, providing the thread to the disk and to the valve bushing as well as screwing in the disk is complex and expensive.
The object of the invention is to provide a hydraulic valve having the initally described features that in terms of manufacture of individual parts and in terms of assembly is more cost-effective.
SUMMARY OF THE INVENTION
This object is achieved in accordance with the invention in that the hydraulic valve is characterized primarily in that the disk is pressed with press fit into the control bore, and in that the valve bushing, starting from the end face, is provided on an exterior surface thereof with a turned groove that is disposed remote from a pressure medium flow. This means that the disk is pressed into the control bore with press fit so that neither it nor the valve bushing must be provided a thread and they are therefore relatively simple to produce. In addition, the valve bushing, starting from the end face, is provided on its exterior a turned groove located remote from a pressure medium flow. This makes it possible to insert the valve bushing with a vacuum into the receiving bore even though the passage between the valve bushing and the receiving bore of the housing is very narrow due to the sealing necessary between the various pressure medium channels. That is, due to the turned groove, a slight expansion in the bushing in the region of the disk that has been pressed in does not make the valve bushing too large.
In a hydraulic valve already known from DE 39 14 094 A1 a disk with press fit is inserted into a valve bushing and the valve bushing has an external turned groove in the region of the disk. However, the disk comprises plastic, so that one cannot expect the valve bushing, which is obviously produced from a metal material, to expand when the disk is pressed in. In addition, the turned groove is disposed in a pressure medium path that encompasses axial passages in the disk, the region of the receiving bore anterior to the valve bushing, the turned groove, and a channel leading off radially from the receiving bore in the region of the turned groove. Pressing the disk in thus has nothing to do with the external turned groove on the valve bushing.
In contrast, in the hydraulic valve in accordance with the invention, there is a turned groove on the valve bushing that has nothing to do with the pressure medium flow.
Advantageous embodiments of a hydraulic valve in accordance with the invention can be seen from the following.
For instance, the valve bushing and the disk are made of materials that are at least substantially the same in terms of their coefficients of expansion. This ensures that the press fit between the disk and the valve bushing is maintained in a large temperature range. Preferably the valve bushing and the disk are each made of aluminum or an aluminum alloy.
It is advantageous if the distance from the end of the turned groove to the face of the valve bushing is greater than the distance from such face of that end of the press segment remote from the face whereby the press segment is between the valve bushing and the disk. Preferably the ratio of these distances is between 1.5 and 2.0.
The depth of the turned groove in the radial direction is preferably less than 10% of the wall thickness of the valve bushing. The depth of the turned groove is substantially less than the depth of an annular slot on the valve bushing that opens outward and that is situated in a pressure medium flow path.
REFERENCES:
patent: 4979542 (1990-12-01), Mesenich
patent: 5191827 (1993-03-01), Kervagoret
patent: 5259414 (1993-11-01), Suzuki
patent: 5377720 (1995-01-01), Stobbs et al.
patent: 5487410 (1996-01-01), Niethammer
patent: 5577534 (1996-11-01), Ward
patent: 5592972 (1997-01-01), Niethammer
patent: 5615860 (1997-04-01), Brehm et al.
patent: 5853028 (1998-12-01), Ness et al.
patent: 5878782 (1999-03-01), Nakajima
patent: 5911400 (1999-06-01), Niethammer et al.
patent: 39 14 094 (1990-10-01), None
patent: 44 23 629 (1996-01-01), None
Neuhaus Rolf
Rettinger Jürgen
Schlöder Robert
Becker R. W.
Hydraulik-Ring GmbH
Michalsky Gerald A.
R.W. Becker & Associates
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