# Patent

## Title
Camshaft adjuster control valve arrangement

## Abstract

In a camshaft adjuster control valve arrangement including a valve housing in the form of a central screw, the valve housing has a central passage of essentially constant diameter extending fully through the central screw.

## Background
This is a Continuation-In-Part Application of pending international patent application PCT/ep2006/006682 filed Jul. 7, 2006 and claiming the priority of German patent application 10 2005 034 275.2 filed Jul. 22, 2005.


BACKGROUND OF THE INVENTION
The invention relates to a camshaft adjuster control valve arrangement mounted to the camshaft by a central screw having an axial opening with a camshaft adjusting valve disposed therein.
DE 198 17 319 C2 discloses a camshaft adjuster valve device having a valve housing which is embodied as a central clamping screw. The valve housing has a blind hole in which a control piston is guided. The blind hole ends before a threaded region of the valve housing. In said threaded region, the valve housing is formed from solid material.
It is the object of the present invention to provide a camshaft adjusting valve involving reduced manufacturing expenditures.
SUMMARY OF THE INVENTION
In a camshaft adjuster control valve arrangement including a valve housing in the form of a central screw by which a camshaft adjustment device is mounted to the camshaft, the valve housing has a central passage of essentially constant diameter extending fully through the central screw.
Such an embodiment permits production on a machine tool with few chucking operations, as a result of which the valve housing can be produced in a particularly cost-effective manner. It is possible to use blanks which very closely resemble a subsequent final contour, for example preferably hollow extrusion blanks or rotary swaging blanks, in particular if the passage duct has an at least substantially constant diameter and/or the valve housing has a substantially constant wall thickness at least in a partial threaded region and in at least one partial guiding region. In addition, as a result of the central passage, it is possible to obtain an advantageous chip discharge and cooling of tool cutting edges, and expensive deburring of blind holes at the end of a guide bore receiving a control piston can be avoided. In this context, “substantially identical” is to be understood to mean that slight deviations from the scope of protection should be encompassed, with the deviations preferably being less than 15% and particularly advantageously being less than 10% or in the range of a maximum of one step of an established thread step according to the DIN standard. “Central” is to be understood in particular to mean that the passage duct extends concentrically through the valve housing. In addition, a partial guide region is to be understood to mean an axial section of the valve housing in which a control piston is guided during operation, in particular within the passage duct.
In a further embodiment, the valve housing has substantially an identical outer diameter in at least one partial threaded region and in at least one partial guide region, as a result of which an advantageous force distribution can be obtained, and an elastic transverse contraction of a guide region or of a fit for the control piston upon tightening of the central screw which may result in jamming of the control piston in particular in the end position can be largely avoided, especially if the tolerances are close to their limits.
In a preferred embodiment, the camshaft adjusting valve device has at least one partition means which is fastened in the valve housing, as a result of which a support face for a spring means and in particular a sealing partition can be created in a structurally simple manner with little production expenditure.
It is additionally possible to obtain advantageous designs of the valve housing and/or of the control piston if a non-return valve is fastened in the valve housing. Here, the one-way valve can be formed separately from the partition means or advantageously at least partially in one piece with the latter, as a result of which it is possible to save on additional components, installation space, assembly expenditure and costs, specifically in particular if the non-return valve and the partition means are designed as a modular unit which can be mounted in the valve housing.
It is possible for components such as in particular the partition means and/or the non-return valve to be fastened in the valve housing by means of various force-fitting, form-fitting and/or cohesive connections which would appear to a person skilled in the art to be expedient, such as for example by means of adhesive connections, screw connections, clamping connections and/or advantageously by means of crimped connections etc. In the case in particular of fastening by means of a crimped connection, the component which is fastened in the valve housing is preferably pressed into the valve housing from a side which, considered in the installed state, faces toward a camshaft, as a result of which undesired repercussions of the fastening process on guide surfaces of the control piston within the valve housing can be avoided.
In a further embodiment of the invention, the valve housing may have at least one integrally formed securing element for securing a control piston, as a result of which it is possible to save on additional components, installation space, weight, assembly expenditure and costs.
If the valve housing has a profile on an inner periphery, which profile is provided for introducing a torque, such as in particular a polygonal profile etc., it is possible for an advantageous, preferably a cylindrical clamping region to be formed on an outer periphery of the valve housing, so that the valve housing can be simply and advantageously clamped during its manufacture.
The invention will become more readily apparent from the following description thereof on the basis of the accompanying drawings:



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a camshaft adjuster with a camshaft adjusting valve device, mounted on a camshaft,
FIG. 2 is a front view of a valve housing shown in FIG. 1,
FIG. 3 shows an alternative camshaft adjusting valve device with an internal hexagon,
FIG. 4 is a front view of a valve housing from FIG. 3 on its own, and
FIG. 5 shows an alternative camshaft adjusting valve device with a non-return valve and a partition means embodied as a modular unit.



DESCRIPTION OF PARTICULAR EMBODIMENTS
FIG. 1 shows in a sectional illustration a camshaft adjuster 22a with a camshaft adjusting valve device according to the invention, mounted on a camshaft 23a. The camshaft adjusting valve device has a valve housing 10a which is in the form of a central screw and which extends centrally through a vane piston 24a which is arranged in a housing 25a, is screwed with an external thread 30a into an internal thread 31a of the camshaft and bears with an integrally formed radial flange 32a directly against an end face, which faces away from the camshaft 23a, of the vane piston 24a and presses the latter against an end face of the camshaft 23a, so that said vane piston 24a is rotationally fixedly coupled to the camshaft 23a. In the radially inner region of the vane piston 24a, the valve housing 10a is coupled by means of a sealing sleeve 40a to the vane piston 24a. 
The valve housing 10a has, on that side of the radial flange 32a which faces away from the camshaft 23a, an external hexagon 34a in order to be able to screw said valve housing 10a into and out of the internal thread 31a of the camshaft 23a (FIGS. 1 and 2). Other profiles suitable for a screw connection would alternatively also be conceivable.
At a side facing toward the camshaft 23a, the housing 25a and the vane piston 24a adjoin a sprocket 26a, and are closed off at a side facing away from the camshaft 23a by a cover 27a, on whose side which in turn faces away from the camshaft 23a is arranged a spring cover 28a with a coil pressure spring 29a. 
The valve housing 10a which is designed as a rotary swaging blank has a central passage 11a with a constant diameter 12a. Alternatively to a rotary swaging blank, the valve housing 10a could also advantageously be formed by an extrusion blank. The valve housing 10a also has, in its threaded region 13a and in its guiding region 14a with the exception of the radial flange 32a, a substantially constant wall thickness 15a and a substantially constant outer diameter 16a. A negligible difference in the wall thickness 15a and in the outer diameter 16a is given by a small step 33a which is of the order of magnitude of an established thread step according to the DIN (Deutsches Institut für Normung [German Institute for Standardization]) standard.
In the guide region 14a, a substantially pot-shaped control piston 19a is guided within the passage 11a, which control piston 19a could also be entirely of tubular design. The control piston 19a is, on a side facing away from the camshaft 23a, designed so as to be adjustable in the axial direction by means of an electromagnetic actuator (not illustrated). Arranged on that side of the control piston 19a which faces toward the camshaft 23a is a compression coil spring 35a which is supported in the direction of the camshaft 23a on a partition 17a and is fastened in the valve housing 10a. The coil pressure spring 35a biases the control piston 19a in the direction of the electromagnetic actuator (not illustrated). The partition 17a is pressed into the valve housing 10a from that side which, considered in the installed state, faces toward the camshaft 23a. The partition 17a is additionally formed partially in one piece with a check valve 18a which is fastened in the valve housing 10a, that is, a seat 36a for a valve ball 37a of the non-return valve 18a is integrally formed on a side, which faces toward the camshaft 23a, of the partition 17a. The non-return valve 18a comprises, in addition to the valve ball 37a, a sleeve 38a which is likewise pressed into the valve housing 10a from that side which, considered in the installed state, faces toward the camshaft 23a. By means of the step 33a, it is possible to avoid an undesired bulging in the region of the sleeve 38a and of the partition 17a. 
In order to secure the control piston 19a within the valve housing 10a or within the passage 11a, the valve housing 10a has, on its end side facing away from the camshaft 23a, in the region of the passage 11a, three integrally formed securing elements 20a which are distributed uniformly over the periphery, are formed by punch impressions and project radially inward into the passage duct 11a (FIG. 2).
FIGS. 3 to 5 illustrate further exemplary embodiments. Substantially identical components are denoted fundamentally by the same reference symbols, with the letters a-c having been added to the reference symbols in order to distinguish the exemplary embodiments. In addition, with regard to identical features and functions, reference can be made to the description with regard to the exemplary embodiment in FIGS. 1 and 2. The following description is restricted substantially to the differences with respect to the exemplary embodiment shown in FIGS. 1 and 2.
FIG. 3 shows a sectional illustration of a camshaft adjusting valve device with a valve housing 10b. The valve housing 10b has, instead of an external hexagon on an inner periphery, a profile 21b which is formed by an internal hexagon (FIGS. 3 and 4). In the region of the internal hexagon, the valve housing 10b has, at its outer periphery, a cylindrical contour which serves as a clamping and contact face during the manufacture of the valve housing 10b. 
FIG. 5 shows a sectional illustration of a camshaft adjusting valve device with a valve housing 10c which corresponds to the exemplary embodiment shown in FIG. 3. A control piston 19c is again movably supported in a passage 11c of the valve housing 10c. A partition 17c and a non-return valve 18c are also fastened in the passage duct 11c. The partition means 17c and the non-return valve 18c are formed partially in one piece and as a modular unit which can be installed in the valve housing 10c. The partition 17c has, on the side, which, in the installed position, faces away from the control piston 19c, an integrally formed tubular projection 39c into which a sleeve 38c, which retains a valve ball 37c of the non-return valve 18c, is pressed.

## Claims

1. A camshaft adjuster control valve arrangement comprising a valve housing (10a, 10b, 10c) formed by a central screw, having a central passage (11a, 11b, 11c) of a substantially constant diameter extending fully through the central screw, at least one partition (17a, 17b, 17c) disposed in the central passage (11a, 11b, 11 c) of the valve housing(10a, 10b, 10c) and being fastened therein, a check valve (18a, 18b, 18c) with a valve member (37a, 37b, 37c) disposed in the central passage (11a, 1lb, 11 c) adjacent the partition (17a, 17b, 17c), said partition holding the valve member (37a, 37b, 37c) in place.

2. The camshaft adjuster control valve arrangement as claimed in claim 1, wherein the valve housing (10a, 10b, 10c) has a substantially constant wall thickness (15a, 15b, 15c) at least in a partial threaded region (13a, 13b, 13c) and in at least one partial guide region (14a, 14b, 14c).

3. The camshaft adjuster control valve arrangement as claimed in claim 1, wherein the valve housing (10a, 10b, 10c) has over its length a substantially constant outer diameter (16a, 16b, 16c) in at least one partial threaded region (13a, 13b, 13c) and in at least one partial guide region (14a, 14b, 14c).

4. The camshaft adjuster control valve arrangement as claimed in claim 1, wherein the partition (17a, 17b, 17c) and the check valve (18a, 18b, 18c) are at least partially formed in one piece.

5. The camshaft adjuster control valve arrangement as claimed in claim 1, wherein the partition (17c) and the check valve (18c) are a modular unit which can be mounted in the valve housing (10c).

6. The camshaft adjuster control valve arrangement as claimed in claim 1, wherein at least one component is pressed into the valve housing (10a, 10b, 10c) from a side which, in the installed state of the valve housing, faces toward the camshaft (23a).

7. The camshaft adjuster control valve arrangement as claimed in claim 1, wherein the valve housing (10a, 10b, 10c) has at least one integrally formed securing element (20a, 20b, 20c) for securing a control piston (19a, 19b, 19c) within the central passage (11a, 11b, 11c).

8. The camshaft adjuster control valve arrangement as claimed in claim 1, wherein the valve housing (10a, 10b, 10c) has a profile (21b, 21c) on an inner periphery, which profile (21b, 21c) is provided for introducing a torque.