CONTROL VALVE HAVING AN OUTFLOW CHANNEL

Abstract

A control valve (1) for a camshaft adjustment device, and to an internal combustion engine having a camshaft adjustment device and a control valve (1) is provided. The control valve (1) includes a valve housing (3) and a pressure medium guiding insert (23) arranged coaxially in a recess of the valve housing (3). A discharge passage (27, 28) of the pressure medium guiding insert (23) transitions into a discharge duct (22) running in the axial direction, wherein the discharge connection T can be connected to the control connection A, B and wherein the discharge connection T is arranged in a region between the second end (8), which is opposite the first end (6), and the control connections A, B.

Claims

1-10. (canceled)

11: A control valve for a camshaft adjustment device, comprising: a valve housing including an inflow connection P, two control connections A and B, and an outflow connection T; a pressure medium-conducting insert, coaxially situated in a receptacle of the valve housing, the insert having an inflow passage, an outflow passage, and two control passages; and a control piston coaxially guided in the pressure medium-conducting insert and having an inflow groove, an outflow groove, and a control groove on an outer circumference, the control piston including a piston head forming an actuating surface on a front side and defining a first end of the control valve on an actuation side, the outflow passage merging into an outflow channel extending in an axial direction, at least one of the two control connections A, B connectable with the outflow connection T via the outflow channel, and the outflow connection T being situated in an area between a second end of the control valve, opposite from the first end, and the two control connections A, B.

12: The control valve as recited in claim 11 wherein the outflow channel is at least partially enclosed by the pressure medium-conducting insert, external dimensions of the pressure medium-conducting insert being adapted to internal dimensions of the receptacle of the valve housing, and the outflow channel being formed at an interface between the valve housing and the pressure medium-conducting insert.

13: The control valve as recited in claim 12 wherein the pressure medium-conducting insert includes a radially interior sleeve-shaped component and an outer sleeve-shaped component, the outer sleeve-shaped component being manufactured as an injection-molded part and the inner sleeve-shaped component being designed as an insert component extrusion-coated by the outer sleeve-shaped component during an injection molding process for the outer sleeve-shaped component.

14: The control valve as recited in claim 12 wherein the pressure medium-conducting insert is manufactured in one piece from plastic or steel.

15: The control valve as recited in claim 11 wherein the inflow connection P is fluidic connectable with the control groove and the control connection A, B via the inflow passage, the inflow groove, and a piston cavity.

16: The control valve as recited in claim 15 wherein the inflow connection P is situated in the area of the second end of the control valve, the control connection A, and the control connection B adjoining axially in the direction of the first end, and the outflow connection T being situated in the direction of the second end.

17: The control valve as recited in claim 16 wherein the control piston has a circumferential inflow groove in the area of the second end, in each case a circumferential outflow groove A, a control groove, and an outflow groove B adjoining axially in the direction of the first end.

18: The control valve as recited in claim 17 wherein the outflow connection T is situated in the area of the second end at the front side of the control valve.

19: The control valve as recited in claim 11 wherein a check valve made up of a spring strip with overlapping ends wound to form a cylindrical valve spring is situated within the piston cavity.

20: An internal combustion engine comprising: a camshaft adjustment device; and a control valve including a valve housing situated in a receptacle of a camshaft and which includes an outflow connection T, two control connections A and B, and an inflow connection P situated within a camshaft, and a pressure medium-conducting insert, situated in a receptacle of the valve housing, and having an inflow passage, an outflow passage, and two control passages, and a control piston guided in the pressure medium-conducting insert and on an outer circumference having an inflow groove, an outflow groove, and a control groove, the outflow passage merging into an outflow channel extending in an axial direction, whereby the outflow connection T connectable with the control connection A, B, and the outflow connection T is connected, via a connection in the camshaft, to a cavity, a hydraulic medium line, or a volume accumulator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is now explained in greater detail based on one exemplary embodiment, with reference to the drawings. Functionally equivalent elements of the explained specific embodiments are denoted by the same reference numerals.

[0018] FIG. 1 shows a longitudinal section of the control valve;

[0019] FIG. 2 shows a longitudinal section of the valve housing of the control valve from FIG. 1; and

[0020] FIG. 3 shows a longitudinal section of the pressure medium-conducting insert of the control valve from FIG. 1.

DETAILED DESCRIPTION

[0021] FIG. 1 shows in the longitudinal section one specific embodiment, by way of example, of a control valve 1 which includes a check valve 2. Control valve 1 is made up of a valve housing 3 and a hollow cylindrical control piston 4 that is axially movably guided in a corresponding cavity in valve housing 3. The adjustment range of control piston 4 is axially delimited by a locking ring 5 on first end 6 and by an end element 7 on second end 8. Valve housing 3 may be accommodated by a cavity in a camshaft 100 and used for controlling a camshaft adjuster 200 for an internal combustion engine 300. A flange 9 together with an external thread 10 is used to connect control valve 1 to the camshaft 100. Valve housing 3 has three openings on its outer circumference: The openings form inflow connection P, as well as first supply connection A, and second supply connection B. An outflow connection T is situated at second end 8 of the valve housing. A filter 12 is situated in the area of the opening, which forms inflow connection P.

[0022] Control piston 4 on its outer circumferential surface has five sections with an expanded diameter, which include four sections with a reduced diameter. These, together with the inner circumferential surface of the valve housing, form a first, a second, a third, and a fourth circumferential annular channel, i.e., inflow groove 13, outflow groove A14, control groove 15, and outflow groove B16, respectively. For controlling camshaft adjuster 200, control piston 4 may assume different switching positions that are characterized by the actual pattern of possible pressure medium paths. A switching position is implemented with the aid of an actuator device, which generally is an electromagnetically activated actuator.

[0023] A push rod which is connected to an armature of the electromagnet is brought into contact with an actuating surface at the front side of the control piston; the force acting on the armature is thus transmitted via the push rod to the control piston and effectuates its axial displacement against the force of a spring 17: The first annular channel/inflow groove 13 may thus be brought into connection with inflow connection P, and the second annular channel/outflow groove A14 may be brought into connection with control connection A. The third annular channel/control groove 15 may be brought into connection with first control connection A, with second control connection B, with both, or with neither.

[0024] A first through opening 18 is provided on the groove base of inflow groove 13, which forms the first annular channel, and a second through opening 19 is provided on the groove base of the control groove that forms the third annular channel. Except for first and second through openings 18, 19, control piston 4 is closed on the side facing away from the spring by a pressure piece 20. Hydraulic medium may thus be conducted via inflow connection P into piston cavity 21, and from there to control connections A, B. Control connection A may be brought into connection with outflow connection T via the second annular channel/outflow groove A14 and via outflow channel 22, and control connection B may be brought into connection with outflow connection T via the fourth annular channel/outflow groove B16 and via outflow channel 22.

[0025] FIG. 2 shows a detailed view of valve housing 3. First and second ends 3, 8 of the control valve are illustrated. Control connections A, B, situated axially and offset over the circumference, as well as inflow connection P are apparent on the inner circumferential surface of valve housing 3. A borehole that forms outflow connection T extends coaxially in the area of second end 8.

[0026] As shown in FIG. 1, control piston 4 is guided within a pressure medium-conducting insert 23. Pressure medium-conducting insert 23 includes an interior component 24 and an exterior component 25. Interior component 24 is made of a metallic material and is enclosed by an exterior component 25 made of plastic. Both components have a sleeve-shaped or hollow cylindrical design. Outer sleeve-shaped component 25 is manufactured as an injection-molded part, and inner sleeve-shaped component 24 is designed as an insert component that is extrusion-coated by the outer component during the injection molding process for the latter.

[0027] FIG. 3 illustrates a detailed view of pressure medium-conducting insert 23. An outflow channel 22 that extends along the circumference in the axial direction is formed on the outer circumference. On the side of pressure medium-conducting insert 23 facing second end 8 of control valve 3, axial outflow channel 22 opens into a radially extending channel 26, via which a connection to outflow connection T may be established. On the side of pressure medium-conducting insert 23 facing first end 8 of the control valve, outflow channel 22 is closed on the end-face side. Two outflow passages 27, 28, via which a connection between outflow connection T, outflow grooves A14 and B16, and control connections A and B may be established, are situated on the base of the groove that forms outflow channel 22 together with the inner circumferential surface of the valve housing. The control connections are connected to the piston cavity via control passages A29 and B30, and the inflow connection is connected to the piston cavity via inflow passage P31.

[0028] As shown in FIG. 1, a check valve 2 that is made up of a spring strip with overlapping ends that is wound to form a cylindrical valve spring is situated within the piston cavity. Due to the winding of the spring strip, an interior end and an exterior end as well as an inner surface and an outer surface of the spring strip are defined, the spring strip at its interior end merging into an axially extending spacer element whose axial ends may be brought into contact with the inner side of the end faces of the control piston. The spacer element is formed by a tongue-like channel having an arch-shaped cross section.

[0029] The axial position of the spring strip within the piston cavity is fixed in such a way that the outer surface of the spring strip in the area of first through opening 18 may be brought into contact with the inner circumferential surface of control piston 4. First through opening 18 may be closed in this way: In the inflow direction, first through opening 18 is unblocked, so that pressure medium may enter piston cavity 21, whereas in the reverse direction, check valve 2 blocks. Pressure peaks are not passed into the area of the inflow line.

LIST OF REFERENCE NUMERALS

[0030] 1 control valve [0031] 2 check valve [0032] 3 valve housing [0033] 4 control piston [0034] 5 locking ring [0035] 6 first end [0036] 7 end element [0037] 8 second end [0038] 9 flange [0039] 10 external thread [0040] 12 filter [0041] 13 inflow groove [0042] 14, A14 outflow groove A [0043] 15 control groove [0044] 16, B16 outflow groove B [0045] 17 spring [0046] 18 first through opening [0047] 19 second through opening [0048] 20 pressure piece, piston head [0049] 21 piston cavity [0050] 22 outflow channel [0051] 23 pressure medium-conducting insert [0052] 24 interior component [0053] 25 exterior component [0054] 26 radially extending channel [0055] 27 outflow passage [0056] 28 outflow passage [0057] 29, A29 control passage A [0058] 30, B30 control passage B [0059] 31, P31 inflow passage P [0060] 100 camshaft [0061] 200 camshaft adjuster [0062] 300 internal combustion engine [0063] A control connection A [0064] B control connection B [0065] P inflow connection P [0066] T outflow connection T