Patent Application
20100300388
This application claims the benefit of German patent application no. DE 10 2009 022 869.1 filed on May 27, 2009, which is incorporated herein and made a part hereof by reference for all purposes.
The invention relates to a vane-type camshaft adjuster system.
From DE 10 2004 039 800 B4 a vane-type camshaft adjuster system for a drive motor is already known. Such a vane-type camshaft adjuster comprises a rotor having five vanes, which are disposed circumferentially between radially inwardly directed webs of a stator. The vanes divide in each case one pressure chamber into two hydraulic chambers working in opposite directions. One pressure chamber of these five pressure chambers has a spring-loaded locking pin, which is aligned parallel to a central axis. When this locking pin is situated in a locking position, the rotor is then fixed relative to the stator in an intermediate position lying between “early” and “late” end positions.
Locking in such an intermediate position that is neither the “early” end position nor the “late” end position is generally also referred to as mid-locking even if this mid-locking is not effected exactly mid-way between the two end positions.
The two hydraulic chambers of the vane-type camshaft adjuster according to DE 10 2004 039 800 B4 are controllable by means of an electrohydraulic 4/4-way valve having a magnet part as an actuator. For this purpose the valve has:
Upon starting of the drive motor, by means of the 4/4-way valve in a first state through simultaneous interconnection of the two working ports the two hydraulic chambers are relieved to an unpressurized state relative to the tank port T. In this unpressurized state the locking pin may move into the locking position. The 4/4-way valve in this case is of a cartridge style of construction. It comprises a bush, inside which a hollow piston is guided in an axially displaceable manner. For this purpose the piston has at the one end a cup base, which is supported under spring loading against an electromagnetically displaceable tappet of the magnet part. The bush has three recesses disposed axially adjacent to one another. The piston on the other hand has circumferential annular control grooves. By displacing the axial position of the annular control grooves relative to the three recesses, a hydraulic fluid coming from the supply port P is conveyed towards the two working ports A, B and/or towards the tank port T.
DE 103 44 816 B4 relates to a further vane-type camshaft adjuster system for a drive motor. This reference discloses a cartridge-style 6/4-way valve which likewise comprises a bush and a piston disposed inside the bush. The 6/4-way valve has a separate position for removing hydraulic fluid from the two hydraulic chambers so that two spring-loaded locking devices may lock in an intermediate position that is neither the “early” end position nor the “late” end position. These two locking devices are radially aligned and disposed in a web of the stator. One of the three ports of the 6/4-way valve is associated exclusively with the two locking devices.
From DE 10 2006 012 733 B4 and/or DE 10 2006 012 775 B4 a vane-type camshaft adjuster system having a 4/3-way valve is known. This valve is of a cartridge style of construction. Inserted into the bush at the inside are non-return valves that take the form of band-shaped rings. By means of these non-return valves, camshaft alternating torques are utilized to allow the camshaft adjuster to be adjusted particularly quickly and/or with a relatively low oil pressure.
From DE 44 22 742 C2 an electrohydraulic valve is already known, which comprises:
The valve is of a cartridge style of construction and comprises a bush having three recesses. Inside the bush a hollow piston is axially displaceable along a running surface. For this purpose there is provided at one piston end a cup base, which is supported under spring loading against a displaceable tappet of an electromagnetic actuator. The piston has a circumferential annular control groove. Provided at the two piston ends are outflow recesses, which are aligned transversely of a central axis of the valve and lead to the tank port T. Provided on the piston, adjacent to the magnet-side outflow recess, is a circumferential rib, past which a hydraulic flow may be conveyed from the magnet-side working port to the outflow recess.
The object of the invention is to provide an economical vane-type camshaft adjuster system that meets the various requirements of various motors.
This and other objects are achieved according to the present invention.
The present invention provides a modular system for the valves of a vane-type camshaft adjuster system. Two different embodiments of valves are proposed. With one example embodiment, a valve with mid-locking and without mid-locking may be constructed using the same bush. With another example embodiment, a valve with and without special utilization of the camshaft alternating torques may be constructed using the same bush.
According to the present invention, one example embodiment of a valve of the vane-type camshaft adjuster system is disclosed, which enables mid-locking with an economical valve. The valve may have details developed in a constructionally identical manner for a vane-type camshaft adjuster system with utilization of the camshaft alternating torques.
According to one advantageous aspect of the invention, it is at the piston end facing the magnet part (i.e. the magnet-side piston end) that an outflow recess leading to the tank port T and aligned transversely relative to the central axis is provided. On the other hand, the other end is designed as a piston-terminating control edge for directing hydraulic fluid to the tank port T. This, on the one hand, achieves cost benefits as the piston therefore has to be provided with relatively few recesses—in particular transverse bores. The piston may also be of a relatively short design, thereby allowing a saving of material not only at the piston but also at the bush. Furthermore, a helical compression spring for spring-loading the piston towards a tappet of the magnet part may be of a relatively short design as this helical compression spring may be supported relatively close to the piston end. The short overall length of the 4/4-way valve also offers advantages in terms of installation space.
In a further advantageous manner the bush and the piston according to the present invention are designed in such a way that it is possible to create a design family of valves for vane-type camshaft adjusters that enables only slight design variations between the valves. These valves may be:
In particular the magnet parts of such valves be of an identical design. The pistons of a valve without mid-locking need differ from the pistons with mid-locking only in that in the more complex variant with mid-locking:
For the constructional realization, there is provided on the piston, adjacent to the outflow recess, a circumferential rib, past which a hydraulic flow coming from the magnet-side working port B may be conveyed to the outflow recess. Furthermore, between the magnet part and the second working port B, a region having an inside diameter that is widened relative to the running surface is provided, thereby forming between this inside diameter and the running surface a run-off edge that is blockable by the rib. Thus, by virtue of the fact that a circumferential rib always forms the run-off edge relative to the recess of the working port B, the piston need not be installed angularly oriented relative to the bush. For this reason, it is also possible to dispense with an anti-rotation element between the bush and the piston and hence reduce costs. If, however, the outflow recess were directly to form the run-off edge relative to the recess of the second working port B, an expensive angular orientation would be necessary. The solution according to the invention comprising a circumferential rib for blocking/releasing of the outflow recess to the piston, on the other hand, makes it possible to allow the piston to run directly along the running surface that is penetrated by the recess for the working port B. The same applies to the embodiment (as described in the previous paragraph) of the other piston end as a control edge. This spring-side piston end may also slide directly along the running surface in the region of the recess which penetrates this running surface of the first working port A, with the result, at this piston end too, that the piston requires no angular orientation and/or anti-rotation element. The running surface may therefore inexpensively take the form of a bore passing through the entire running region. The internal machining of the running surface may in this case be carried out by a high-quality surface treatment.
In this case, in an advantageous manner the inside diameter of the bush in the axial region between the magnet part and the outer web positioned closest thereto may be designed with an inside diameter that is widened relative to the running surface. For the external machining of the bush it is therefore possible to clamp the bush tightly in a tool, for example a three-jaw chuck, without the bush being plastically deformed to such an extent that the running surface becomes inoperative.
Further advantages of the invention emerge from the claims, the detailed description and the drawings.
The present invention will hereinafter be described in conjunction with the appended drawing figures, wherein like reference numerals denote like elements, and:
The ensuing detailed description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the ensuing detailed description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing an embodiment of the invention. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth in the appended claims.
In accordance with an example embodiment of the present invention as shown in
The stator 101 comprises a cylindrical stator basic body 103, from the inside of which webs 104 project radially inwards at uniform intervals over the circumference. Formed between adjacent webs 104 are pressure chambers 105, into which pressure medium is introduced. The introduction of this pressure medium is effected in a controlled and/or regulated manner by means of a 4/4-way valve and/or 4/3-way valve in accordance with the present invention that is described below in connection with the figures. Protruding between adjacent webs 104 are vanes 106, which project radially outwards from a cylindrical rotor basic body 107 of a rotor 108. These vanes 106 subdivide the pressure chambers 105 between the webs 104 in each case into two hydraulic chambers 109 and 110.
The webs 104 lie with their end faces sealingly against the outer lateral surface of the rotor basic body 107. The vanes 106 in turn lie with their end faces sealingly against the cylindrical inner wall of the stator basic body 103.
The rotor 108 is connected in a rotationally fixed manner to the camshaft 127. In order to vary the angular position between the camshaft 127 and the crankshaft, the rotor 108 is rotated relative to the stator 101. For this purpose, depending on the desired direction of rotation the pressure medium in the first hydraulic chambers 109 and/or 110 is pressurized, while the second hydraulic chambers 110 and/or 109 are relieved in the direction of the tank.
The rotor 108 is positively fixable in a rotationally fixed manner relative to the stator 101. For this purpose a locking pin 121 is provided, which is aligned parallel to a central axis 125 of the vane-type camshaft adjuster. This locking pin 121 is preloaded by a small compression spring and in a locking position of the rotor 108 relative to the stator 101 may engage into a location hole 126 of the stator 101. This location hole 126 lies, in terms of the circumference, in an intermediate position between the “early” and “late” end positions.
In this case, the 4/4-way valve 81 takes the form of a cartridge valve. This cartridge valve comprises a hydraulic part 83 and a magnet part 5. The hydraulic part 83 has a piston 13 and a bush 15. The piston 13 runs inside the bush 15 along the running surface 85 thereof. The piston 13 is preloaded by means of a helical compression spring 9, which is supported relative to a support ring 11 on the bush 15. The bush 15 is provided with openings 86, 87, 88, which in the illustrated case are rotationally symmetrical bores. These openings 86, 87, 88 represent the first working port A, the second working port B and the supply port P. The arrows indicate the regular oil directions. At the end face of the hydraulic part 83 a central opening 17 is provided for the tank port T. This tank port T lies at right angles to the other three ports A, B and P of the 4/4-way valve 81. The opening 17 for the tank port T lies centrally inside the support ring 11. The helical compression spring 9 encircles this opening 17 for the tank port T. The piston 13 is hollow. The piston 13 is provided with outflow recesses 21, which at the magnet-side piston end establish the connection to the hollow space 89 of the piston 13. In and around the 4/4-way valve 81 a series of seals are mounted, which during operation keep the hydraulic fluid away from the environment and from the parts not supplied with hydraulic fluid. In this case, the seal 25 as a magnet-part seal seals off the magnet part 5 from the hydraulic part 83. The tappet 41, which rests against a cup base 93 of the piston 13, is a tappet 41 that is preloaded with hydraulic fluid and situated in the hydraulic fluid. A pole seal 63 and a non-visible coil seal ensure that the hydraulic fluid situated in the magnet part 5 cannot escape outside, i.e. outside of a housing 27. The housing 27 at its side close to the hydraulic part 83 verges into a flange 29 that is provided with fastening openings, i.e. the fastening bores 31. The pole core 39 succeeding the hydraulic part 83 is connected by beads 33 to the housing 27. These beads 33 are disposed in the region of the pole seal 63. Inside the housing 27 a coil, an armature, the pole core 39 and the tappet 41 are disposed. For further details about the magnet part 5 reference is made to DE 10 2004 039 800 B4, which in this regard is to be regarded as incorporated by reference in this application.
The armature in this case may be moved to and fro between two armature chambers, which are in fluidic communication with the hydraulic part 83 of the 4/4-way valve 81 when the piston 13 is outside of its end stop position.
On the opposite end of the housing 27 to the opening 17 for the tank port T an electric plug 47 is fastened.
A tappet oil space 77 is connected by the outflow recesses 21 to the central opening 17 for the tank port T. This connection of the hydraulic part 83 to the magnet part 5 of the 4/4-way valve 81 is established by means of an edge-formed portion 23. This edge-formed portion 23 is attached laterally to the bush 15.
In the non-energized state of the magnet part 5, the piston 13 blocks off the rear hydraulic channel (coming from armature chambers) in the magnet part 5 from the tank port T. The helical compression spring 9 then experiences no counterforce and is in its outspread, most extended and relaxed position. All of the hydraulic fluid from the hydraulic chambers 110, 109 of the vane-type camshaft adjuster escapes through the opening for the tank port T. Via:
The inside diameter of the bush 15 in the axial region between the magnet part 5 and a shoulder 34 is designed with an inside diameter that is widened relative to the running surface 85. This shoulder 34 lies approximately at the outer web 50 positioned closest to the magnet part 5. For the external machining of the bush 15 it is therefore possible to clamp the bush 15 tightly in a three-jaw chuck without the bush 15 being plastically deformed to such an extent that the running surface 15 becomes inoperative.
From
From the diagram according to
The flow from the supply port P to the first working port A and/or the second working port B is accordingly controllable in proportion to the current. In this case, just as in the 4/4-way valve according to
The constructionally identical design of the bushes in the case of the use of different pistons to realize a vane-type camshaft adjuster system in accordance with the present invention, with and without a special outlet position for the mid-locking, may be used also in vane-type camshaft adjuster systems with special utilization of camshaft alternating torques, such as is described for example in DE 10 2006 012 733 B4.
In this regard
In this case, a third band-shaped non-return valve 276 is additionally provided in an inner annular groove 277. This third non-return valve 276 is however a pump protection valve, which is basically of an identical construction to the two non-return valves 270, 271. This pump protection valve may however have a different response force.
In an alternative example embodiment of the present invention according to
The previously described valve design embodiments are not limited to proportional valves but may be used also in on-off valves.
Depending on the operating conditions of the valve, filters may be provided in front of all of the openings to protect the running surfaces between piston and bush.
The hydraulic part of the illustrated valves may also be used in a so-called master valve. In this case, the bush is not connected directly to the magnet part. Instead, the hydraulic part is disposed centrally in the rotor of the vane-type camshaft adjuster so that the bush rotates jointly with the piston. The magnet, on the other hand, is disposed in a rotationally fixed manner relative to the cylinder head so that a relative movement occurs between the tappet of the magnet part and the piston.
The described forms of construction are merely exemplary embodiments. A combination of the described features for different forms of construction is equally possible. For example, a set of valves may be provided which includes different embodiments of valves and pistons described herein. Such a set of valves may have a modular construction. Further, in particular non-described features of the device parts belonging to the invention are to be gathered from the geometries of the device parts that are represented in the drawings.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 022 869 | May 2009 | DE | national |
