The invention relates to a camshaft adjustment device for an internal combustion engine for setting the phase position of a camshaft relative to a camshaft drive wheel, wherein the camshaft adjustment device comprises a chamber housing surrounding the camshaft drive wheel and an actuating rotor held therein. The actuating rotor is arranged concentric to the axis of rotation of the chamber housing and is arranged so that it can pivot in the chamber housing, so that the actuating rotor can be pivoted in the interior of the housing relative to the housing, and in this way about its axis of rotation over a structurally defined angular range. The actuating rotor here has multiple chamber flanks that project radially outward and form multiple oil chamber sections in each chamber of the housing in interaction with radially inward projecting webs of the chamber housing. The chamber flanks are equipped with sealing strips, wherein the oil chamber sections each separated by a chamber flank of the actuating rotor are sealed relative to each other. The sealing strips are here inserted into radial grooves that are formed in the chamber flanks.
Through the use of camshaft adjustment devices, in a 4-stroke internal combustion engine it is advantageously possible to change the phase position of a camshaft relative to a drive wheel driven by a timing chain, a toothed belt, or some other type of drive system. In this way it is possible to adjust the control times of the valves driven by each camshaft advantageously to the instantaneous load state of the internal combustion engine.
The invention is based on the objective of creating a camshaft adjustment device in which a required setting of the phase position of a camshaft relative to a drive wheel can be created by oil-hydraulic paths and advantages are produced for the sealing of the chamber sections and the realization of internal fluid connection paths.
The object stated above is achieved according to the invention by a camshaft adjustment device for an internal combustion engine, with:
In this way it is advantageously possible to realize a fluid connection path directly via each sealing strip, wherein this path allows a fluid passage in one flow direction and blocks the fluid passage in the opposite direction.
The sealing strip and the check valve device here preferably form a sub-assembly that is completed before the sealing strip is inserted into the actuating rotor.
The check valve device preferably comprises a closing element that is slightly biased in a closed position in the base state. This closing element is preferably formed as a flat disk that sits on the opening area of a hole. As an alternative, the closing element can also be constructed as a ball-like, dome-like, or also merely, for example, as a conical component, which is suitable for blocking a fluid passage path in one structurally defined direction and allowing a fluid passage in the opposite direction.
One embodiment of the invention that is especially advantageous with respect to high functional reliability and minimal requirements for installation space is given in that the check valve device comprises a flat valve plate. This valve plate is preferably made from a steel material, in particular, a structurally treated spring steel material. The valve plate can be shaped so that the valve plate comprises a spring arm, wherein this spring arm has a smaller width than the head section of the valve plate optionally blocking the fluid connection path. Each head section then forms the closing element mentioned generally above.
The check valve device can be further constructed advantageously so that the spring arm is positioned on the allocated sealing strip. Here, a positioning geometry, e.g., in the form of a depression, hole, slot, or pocket can be formed on the sealing strip, through which the spring arm can be fixed in the correct position on the sealing strip. The spring arm can be fixed directly on the allocated sealing strip. The fixing of the check valve device can also be implemented so that this is produced only after the sealing strip is inserted into the actuating rotor and in this way just in interaction with the actuating rotor.
The control time actuating device according to the invention is preferably constructed such that the sealing strips are inserted so that they can move at least slightly in the radial direction in a guide groove formed in a dividing flank of the actuating rotor, wherein in each sealing strip a guide geometry is also formed and an additional valve element is guided on this guide geometry such that this can be moved according to the measure of an oil pressure applied to the valve element into different positions, wherein the fluid passage already controlled by means of the check valve can be adjusted, in particular, blocked, by means of this valve element through each fluid connection path running in the sealing strip.
The camshaft adjustment device can further be constructed so that this comprises a drive wheel that is connected as such to the chamber housing. The camshaft is then connected to the actuating rotor. The drive wheel can be constructed here, in particular, as a chain or toothed belt wheel or also as a gear for a wheel drive. The drive wheel can take over the function of a housing part, in particular, a closing cover of the chamber housing. As an alternative to the construction described above, it is also possible in a type of kinematic reversal, to connect the specified drive wheel to the actuating rotor and then the camshaft to the chamber housing. In this variant, the actuating rotor can be guided so that it rotates precisely advantageously to an end section of the camshaft.
The sealing strip can be formed according to one especially preferred embodiment of the invention such that the guide geometry guides the valve element so that it can be moved radially relative to the axis of rotation. The valve element can be constructed so that it has a non-round cross section, wherein a guide pocket with a complementary cross section is then formed in the sealing strip. One alternative that is especially advantageous with respect to production relative to the variant specified above consists in that the valve element is shaped so that it has a circular cross section. In the sealing strip, a cylindrical blind hole is then formed in which the valve element is guided so that it can move smoothly with the typical passages for slider valves. This valve element can then block the fluid connection path that can be blocked unidirectionally by the check valve device actuated by oil pressure.
It is also possible to integrate a mechanism in the sealing strip through which the blocking effect of the check valve device can be reversed. It is also possible to integrate a mechanism in the sealing strip through which the check valve device can be temporarily locked so that this does not open. It is also possible to integrate a mechanism in the sealing strip through which the blocking effect of the check valve device can be canceled, so that this is permanently opened. This mechanism can comprise, in turn, a valve or switch element that can be moved in a defined way by applying oil pressure on a control channel, which offers the previously mentioned functions to the check valve device, in particular, to the plate valve head, in the set switching position, in interaction with the mechanism.
The valve element and the sealing strip are preferably supported against each other by a spring device. This spring device can be constructed as a helical or cylindrical spring that is biased slightly in the axial direction, wherein this spring device can be positioned in a pocket formed in the sealing strip.
The valve arrangement realized in interaction between the sealing strip and valve element is preferably constructed so that the valve element is open toward the base area of the sealing strip and the valve element is pressured with compressed oil from the area of the groove base of the guide groove formed in the actuating rotor. Then, also for the assembly of the camshaft adjustment device, the valve element can be inserted into the sealing strip from this lower base area.
The invention is essentially directed toward a camshaft adjuster for a control drive, in particular, in the form of a chain or belt drive. Here, a valve element is integrated into the sealing strips or flanks by means of which a hydraulic open circuit and, in particular, a blocking of the agent, can be created, which is required as needed. The valve elements are controlled by oil pressure and are biased by a compression spring in a starting position. The fluid passage is also controlled by a so-called check valve, i.e., a valve that allows fluid passage in only one direction.
The use of valve elements (also control pistons) in the sealing strips produces an advantageous use of the installation space and the material of the sealing strips. According to the invention, that is, in the needed sealing strips, the function of a valve mechanism is integrated. The connection of the check valve to each sealing strip produces an advantageous formation of a sub-assembly.
In the context of the present description, the device designated as a check valve is a system that comprises a valve or blocking mechanism that has the effect that a fluid flow guided via this system can flow only in one flow direction, but a flow in the opposite direction is prevented by a blockage. Smaller oil flows in the opposite direction, especially oil flows that occur or are necessary until the check valve is closed, are permitted in this way. In the present example, the check valve is preferably designed so that it controls the fluid passage with high dynamic response, so that, for example, dynamic pressure fluctuations in the chamber sections caused, for example, by changes in the loads, can trigger an oil flow in a direction defined by the check valve device.
Additional details and features of the invention are given from the subsequent description in connection with the drawing. Shown are:
The diagram according to
According to the invention, a fluid connection path P that is only indicated here and as such connects the first and the second chamber sections C1, C2 is formed in the respective sealing strip 3, wherein, in this fluid connection path P, a check valve device CV is integrated. Through this check valve device CV it is advantageously possible to permit a fluid passage in a flow direction defined by the structural type of the check valve device CV directly through the fluid connection path P running through the respective sealing strip 3 and to block a fluid passage in the opposite direction.
In the embodiment shown here, the check valve device CV comprises a valve plate CV1 that is connected to a spring arm CV2. The spring arm CV2 is fixed, as will be further discussed below, on the allocated sealing strip 3.
As also discussed in connection with the description of the other figures, a guide geometry is formed in the respective sealing strip 3 and a valve element not shown here is guided in this guide geometry such that it can be displaced into different positions according to the measure of an oil pressure applied to the valve element. The oil pressure for actuating the valve element is applied via the oil channel SP that can be seen here, which opens into the base area of the guide groove 2c of the actuating rotor 2. The specified valve element not yet visible in this view also affects the fluid flow via the fluid connection path P.
As can be further seen from the view according to
As an alternative to the shape of the fluid path guided via the dividing flank 2a, which is especially advantageously in terms of production technology, in the form of a recess 2d that is open at the edges, it is also possible to form, in the dividing flank 2a, a hole or some other recess that allows a fluid flow via the fluid connection path P leading through the sealing strip 3. As far as the entire construction allows it, it is also possible to anchor the sealing strips 3 deep in the actuating rotor 2 such that the dividing flanks 2a can be eliminated or these are reduced with respect to their radial projection over the base surface 2b of the actuating rotor so far that the valve plate CV1 and optionally also the whole valve arm CV2 come free from the actuating rotor 2.
In the embodiment shown here, the contact geometry between the visible sealing strip 3 and the inner wall 1a of the chamber housing 1 is shown simplified. In the area of each edge surface of the sealing strip 3a facing the inner wall la, in particular, surface curvatures, grinding patterns, and optionally also other sealing agents, in particular, elastomer inserts that support the sealing effect of the sealing strips 3. The lateral flanks of the sealing strips 3 can be constructed so that these offer an especially high sealing effect relative to the adjacent radial surfaces of the closure cover of the chamber housing 1. In the sealing strips 3 or the grooves 2c, sealing agents, in particular, elastomer inserts, can also be provided that prevent a fluid passage through the adjacent movement gap area. The actuating rotor 2 and the chamber housing 1 are preferably matched to each other with respect to the materials being used and the provided dimensions so that movement gap dimensions that are too narrow or too large cannot be set in the scope of the practice-relevant temperature spectrum.
The view according to
The view according to
The chamber housing 1 visible here is covered axially by a chamber housing cover 1d and a drive wheel 1e. The actuating rotor 2 is guided so that it can pivot, sealed, between the chamber housing cover 1d and the drive wheel 1e while leaving a sufficient movement play. The check valve CV shown in this view by dashed lines is constructed as a leaf spring valve and fixed on the sealing strip 3. The valve head CV1 only partially visible in this view sits on the surrounding area of the passage hole P1. The bottom side of the valve head CV1 and the flat side of the sealing strip 3 facing this head here form a closed surface system. This includes an opening state when the valve head CV1 is raised from the sealing strip 3 and it includes a closed state when the valve head CV1 contacts the sealing strip 3.
The view according to
As is visible from
The additional setup of the sealing strip according to
The additional setup of the sealing strip according to
The diagrams according to
The diagram according to
The diagrams according to
The diagram according to
The diagrams according to
Chamber housing
1
d Chamber housing cover
1
e Drive wheel
2 Actuating rotor
2
a Dividing flanks
2
b Base surface
2
c Guide groove
2
d Recess
2
e Radial wall
3 Sealing strips
3
a Flat sides
3
b Flat side, side surface
3
c Pocket
3
d Blind hole
3
e Insert pocket
3
f Valve element hole
3
g End side
3
h End side
3
k Groove
4 Retaining frame
4
a Stroke limiting device
C Pressure chambers
C1 Chamber section
C2 Chamber section
CV Check valve device
CV1 Valve plate, valve head
CV2 Spring arm
CV3 Retaining foot
CVa Fastener
CVb Fastener
CVc Fastener
CV4a Retaining clamps
CV4b Retaining clamps
P Fluid connection path
P1 Passage hole
SP Oil channel
SV1 Control valve element
SV2 Spring device
X Axis of rotation
Number | Date | Country | Kind |
---|---|---|---|
10 2014 214 610.0 | Jul 2014 | DE | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/DE2015/200207 | 3/27/2015 | WO | 00 |