Patent Application
20080264365
The invention relates to a camshaft adjuster for an internal combustion engine, in which lubrication is performed by means of a lubricant flow, especially according to the preamble of Claim 1, 12, 17, 18, or 20.
Camshaft adjusters can be roughly classified as follows:
A. Phase adjusters with a control element, that is, a functional unit, which joins in the mass flow or energy flow formed, for example, hydraulically, electrically, or mechanically and rotates with gear elements of the camshaft adjuster.
B. Phase adjusters with a separate setting element, that is, a functional unit, in which the control parameter required for the control method of the control element is formed from the controller output parameter, and a separate control element. Here, there are the following structural forms:
a. Phase adjusters with a co-rotating actuator and a co-rotating control element, for example, a step-up ratio gear, whose adjustment shaft can be advanced by a co-rotating hydraulic motor or centrifugal force motor and can be reset by a spring.
b. Phase adjusters with a co-rotating control element and a stationary, engine-fixed actuator, for example, an electric motor or an electrical or mechanical brake, see also DE 100 38 354 A1, DE 102 05 034 A1, EP 1 043 482 B1.
c. Phase adjusters with a direction-dependent combination of solutions according to a. and b., for example, an engine-fixed brake, in which part of the brake power is used for adjustments toward an advanced position, in order to tension a spring, which allows resetting after the brake is deactivated, see also DE 102 24 446 A1, WO 03-098010, US 2003 0226534, DE 103 17 607 A1.
In systems according to B.a. to B.c., actuators and control elements are connected to each other by an adjustment shaft. The connection can be switchable or non-switchable, detachable or non-detachable, lash-free or with lash, and flexible or stiff. Independent of the structural form, the adjustment energy can be realized in the form of supply through a drive output and/or brake output, as well as with the use of leakage power of the shaft system (e.g., friction) and/or inertia and/or centrifugal force. Braking, advantageously in the adjustment direction of “retarded” can also be realized under the full use or shared use of the friction power of the camshaft. A camshaft adjuster can be equipped with or without mechanical limiting of the adjustment range. As a gear drive in a camshaft adjuster, one-stage or multiple-stage triple-shaft gears and/or multiple links or coupling gears are used, for example, in structural form as a wobble-plate gear, eccentric gear, planetary gear, undulating gear, cam-plate gear, multiple-link or linked gear, or combinations of the individual structural forms in a multiple-stage construction.
For operation of the camshaft adjuster, a lubricant must be fed to lubricating positions, especially bearing positions and/or rolling toothed sections, wherein the lubricant is used for lubricating and/or cooling components of the camshaft adjuster that can move relative to each other. For this purpose, the camshaft adjuster has a lubricant circuit, which can be coupled, for example, with the lubricant circuit of the internal combustion engine.
The present invention is based on the object of providing a camshaft adjuster with an improved lubricant circuit.
According to the invention, the objective is met by the features of Claim 1. Alternative or cumulative solutions for meeting the objective form the basis of the invention emerge accordingly from the features of Claim 12, 17, 18, and/or 20. Other constructions of the solutions according to the invention emerge accordingly from the dependent Claims 2 to 11, 13 to 16, 19, 21, 22.
The invention is based on the idea that for known camshaft adjusters, the flow rate of the lubricant in the camshaft adjuster is determined by the line cross sections, the pumping capacity of a pump in each operating state, the ambient temperature, and the type of lubricant flow being used and the degree of contamination. The selected flow cross sections, in particular, in the region of the supply and discharge, are defined by production-specific needs. In the operation of the camshaft adjuster, the applicant has determined that a gear drive of a camshaft adjuster, under some circumstances, becomes nearly “flooded” with lubricant, in particular,
at high lubricant pressures, if this is provided by the lubricant circuit of the internal combustion engine, and
at a low viscosity of the lubricant, for example, at high rotational speeds under high temperature.
In this way, too much energy is lost in the camshaft adjuster due to churning work to be performed. Under some circumstances, the lubricant becomes greatly foamed. Furthermore, due to the large throughput of the lubricant through the camshaft adjuster, the lubricant pressure of the internal combustion engine can decrease, which can result in degraded lubrication of the other paths of the lubricant circuit. Furthermore, a poorer overall efficiency of the internal combustion engine can be produced due to high hydraulic waste power, which can result in increased fuel consumption.
Therefore, the unpublished application of the applicant with the title “Device for changing the control times of an internal combustion engine” from Dec. 23, 2004 with the internal filing number of the applicant of 4626-10-DE proposes to insert a throttle for the lubricant flow in the camshaft adjuster. Such a throttle can be formed by a tooth gap of a crown gear or by grooves running in the radial direction between individual components of the camshaft adjuster.
On the other hand, in the operation of a camshaft adjuster it has been shown that combustion and contamination residue contained in a lubricant of the engine could lead to temporary or permanent functional disruptions in the adjustment mechanism. This can lead to silting or contamination of a gear drive of the camshaft adjuster. Due to the contaminants, increased wear and also increased waste power can be produced due to the contaminant particles in the functional surfaces for the adjustment of the camshaft adjuster.
If one considers providing a diaphragm or a throttle through targeted shaping of the cross sections of the flow channels in the camshaft adjuster, then this requires a complicated production of the cross sections in the region of the throttles or diaphragms. For example, if a diaphragm is to be provided with a small opening cross section, then this requires a diameter jump to a small diameter in the region of the diaphragm, which can be produced by a drill with a small diameter, which is possible only under increased production requirements and the risk of breakage of the drill for rough conditions of use.
Such complicated production possibilities for a diaphragm or a throttle are avoided according to the invention in that, initially, a flow channel of the camshaft adjuster can be produced without a diaphragm or throttle, for example, with a large and/or constant diameter or ring channel. The flow channel thus can be provided with simple production methods and with safe processing. After production of the flow channel, a flow element is inserted into this channel, wherein this element is constructed separate from the components defining the flow channel. The flow element has contours such that a diaphragm or a throttle is created. The contours of the diaphragm or throttle thus can be produced separately from the other components, wherein, for the spatially limited flow element, separate production methods and/or materials can be used. For one construction of the flow element, advantageously the flow element can have through openings in the interior for the diaphragm or throttles and/or can limit a diaphragm or throttle on one side in the region of inner or outer contours, while another limit of the diaphragm or throttle is guaranteed by a component limiting the flow channel.
Through the use of the flow element, under some circumstances, an exchange of the diaphragm or throttle is enabled, because this is inserted into the flow channel and can be removed from this channel again.
On the other hand, increased variability of the flow relationships is given, because, under some circumstances, for different application purposes of the same camshaft adjuster, for basically the same drilling pattern in the construction of the flow channels, different flow elements can be inserted for adapting to different components of the lubricant circuit or the motor oil circuit.
Furthermore, the invention is based on the knowledge that for flow channels with relatively large flow cross sections, with a rise in temperature of the lubricant, the lubricant flow increases exponentially. In contrast, under use of a flow element in the form of a diaphragm or throttle, the influence of the temperature on the lubricant flow decreases or is nearly eliminated for otherwise unchanged flow conditions.
According to another construction of the invention, the flow element is arranged in the inlet region of the lubricant into the gear drive and/or in the outlet region of the lubricant out of the gear drive, so that throttling can be performed selectively in the region of interest. If throttling is already performed in the inlet region of the lubricant, then increased pressures could be withstood due to the throttling of the gear drive, by which the sealing requirements in the gear drive are not increased unnecessarily.
The flow element is, in particular,
connected with a positive fit to the flow channel, wherein the flow element can engage in suitable recesses or grooves of the components limiting the flow channel,
connected with a friction fit to the flow channel, wherein the flow element is inserted, for example, under an elastic biasing stress, into the flow channel, or
connected with a material fit to the flow channel, for example, by an adhesive,
wherein combinations of a positive-fit, friction-fit, or material-fit connection are also possible.
Flow elements made from plastic or an elastomer have proven to be advantageous with respect to the flow relationships in the region of the surface, the elastic properties, the chemical interaction with the lubricant, and/or the positive-fit, friction-fit, or material-fit connection to the flow channel.
According to one improvement, the flow channel has, in the region, in which the flow element is inserted, a circular ring-shaped cross section. In contrast to throttles or diaphragms, which are formed in the shape of boreholes with circular cross section, the circular ring-shaped cross sections cannot become blocked as easily due to the increased extent in the circumferential direction, because if need be partial circumferential regions can be added.
In another construction of the invention, a circular ring-shaped cross section for a flow channel can be formed between an outer surface of a central screw screwed into the camshaft on the end face and an inner surface fixed to the camshaft, for example, a hollow shaft or a gear element, so that already present components are used for the flow channel and the surfaces limiting the flow channel can be formed by outer and inner contours of the components with relatively large diameters.
Advantageously, in a camshaft adjuster according to the invention, the flow element is pressed elastically in the radial direction and under radial pressure against a boundary of the flow channel, wherein such pressure can be performed on the inside and/or outside in the radial direction.
Due to the reduced flow cross sections, the throttles or diaphragms form areas raising the risk of overriding blockage with contaminant particles or sludge. This condition can be taken into account according to another embodiment of the invention in that a filter element is arranged upstream of the flow element. Here, the filter element can be arranged upstream of or in the camshaft adjuster. For the case that the filter element is arranged in a flow channel of the camshaft adjuster, the filter element can be constructed separate from the throttle or else as an integral element of the flow element. Furthermore it is to be taken into consideration that the filter element similarly generates a throttling effect, so that a throttle or a diaphragm must be dimensioned under consideration of the throttling effect of the filter element.
Advantageously, the diaphragm or throttle is created by a change in cross section perpendicular to the flow direction of the lubricant. For the case of a circular diaphragm, this means that in the region of the diaphragm, the circular diameter is reduced relative to the other flow cross section. For the case of a circular ring-shaped flow cross section, this means that the radial extent of the circular ring is reduced in the region of the diaphragm or throttle.
In an alternative or cumulative construction of the invention, the diaphragm or throttle is created by a change in cross section in the circumferential direction relative to the flow direction of the lubricant. For example, for one circular ring-shaped cross section through the flow element, the flow cross section is divided into individual circle segments, whose total surface area is smaller than the original circular area of the flow cross section. For a circular ring-shaped flow cross section, for example, the flow element can block individual circumferential areas of the circular ring-shaped flow channel.
Furthermore, the invention proposes to connect several flow elements in series or in parallel. Through the use of a series connection for a path of the lubricant, the area for influencing the flow can be increased. In a parallel connection of several flow elements in different flow paths to different lubricating points, through the same or different flow elements, the lubricant flow at the lubricating points can be selectively influenced corresponding to the requirements at the lubricating point, so that lubricating points with increased lubricant demands can be supplied with more lubricant or the inverse.
According to another solution to meet the objective forming the basis of the invention, the flow of lubricant is influenced by a flow element, whose flow properties can be changed during the operation of the internal combustion engine. In this way, the flow element can be constructed as an integral component of the flow channel or as a separate flow element, as described above. By changing the flow properties, a change in the lubricant flow, for example, due to the lubricant heating up can be counteracted. On the other hand, by changing the flow properties of the flow element, it is possible to selectively change the pressure, the velocity, and the lubricant flow in the region of the lubricating point or in the feeding area to this lubricating point, if there is increased or decreased lubricant and/or cooling requirements due to changed operating conditions, so that the individual operating conditions can be better taken into account.
A change in the flow element due to the influence of the flow properties can take place automatically, for example, in the form of a thermocouple or in the form of mechanically self-correcting solutions. The use of an adjustment device for changing the flow element is also possible, wherein this adjustment device is acted upon by a suitable control or regulating device.
In another construction of the camshaft adjuster according to the invention, the flow element can be temporarily closed completely. Such a flow element can be closed completely, for example, when the engine is stopped. Also possible is a repeated closing of the flow element during operation, which can generate pulses in the lubricant, which can, under some circumstances, reinforce a targeted lubrication and cooling effect and which can increase the area covered by the lubricant.
Furthermore, it is possible that the flow properties of the flow element can be changed in a motion-controlled way by rotating the camshaft, the camshaft adjuster, or the gear drive. For example, the centrifugal force of the flow properties of the flow element can be regulated with the rotation of the camshaft. In an alternative construction, in the feeding area between two boreholes of components that can move relative to each other, for example, the cylinder head and the camshaft, by which a lubricant transfer is guaranteed, the transfer cross section can be guaranteed only in select relative positions, while for other relative positions, the transfer cross section is closed partially and/or completely, so that the lubricant can be transferred only intermittently.
Another solution for meeting the objective forming the basis of the invention takes advantage of an already existing hollow cylinder-shaped intermediate space, which is arranged between a central screw and a recess of the camshaft and in which a first partial region of this intermediate space forms a first flow channel, wherein the manufacturing dimensions for the outer diameter of the central screw and the inner diameter of the recess define the gap height of the ring-shaped flow channel. In an outer second partial region of the intermediate space there is a hollow shaft, which forms a second flow channel on the outside and/or inside in the radial direction. Due to the dimensions of the hollow shaft, the second flow channel is equipped with a smaller flow cross section than the first flow channel. An additional throttle or diaphragm is created in such a way that in the transfer cross section between the first flow channel and the second flow channel there is a projection, for example, the central screw, the hollow shaft, or the camshaft, or an additional component, which again reduces the second flow channel in this region and thus creates a throttle or diaphragm. This represents an especially simple realization for a diaphragm or throttle, which uses the already existing components and allows the production of the diaphragm or throttle with small opening cross section with nevertheless large dimensions of the involved components.
For another solution to meet the objective forming the basis of the invention, in the intermediate space named above there is a radial groove in the camshaft. In this case, a diaphragm is created in such a way that the transfer cross section from the first partial region to the radial groove is partially closed by an end face of the hollow shaft similarly arranged in the intermediate space. In this case, the diaphragm can be realized without the necessity of manufacturing small opening cross sections through a borehole of small diameter or the like by shaping the central screw and the recess of the camshaft and also the groove and the hollow shaft.
A multi-functional use of the groove is then given when the groove has an outer dead space in the radial direction, in which particles can be deposited due to a centrifugal force exerted on the lubricant.
Another solution to meet the objective forming the basis of the invention involves the transfer of the lubricant from a cylinder head-fixed component, for example, a camshaft bearing, to the camshaft. For such transfer, the cylinder head-fixed component has at least one outlet opening, from which the lubricant enters into at least one inlet opening of the camshaft. In this case, in a simple way—without the need for manufacturing a throttle or diaphragm with a small borehole diameter, a small groove width, or the like, a throttle or diaphragm can be created in such a way that the inlet opening of the camshaft and the outlet opening of the cylinder head-fixed component do not align with each other, so that the transfer cross section is given by the larger cross section of the inlet opening and the outlet opening, but instead the inlet opening and the outlet opening are arranged offset relative to each other, so that the opening cross section of the diaphragm is given by the only partial overlap of the inlet opening and the outlet opening. Such an offset involves, for example, an offset of the inlet opening and outlet opening in the circumferential direction and/or an axial offset in the direction of the longitudinal axis of the camshaft.
Such a construction is then also possible when the inlet opening or the outlet opening is constructed as a groove running partially or completely in the circumferential direction, while the other opening is constructed as a borehole.
Advantageously, the measures according to the invention are used for a camshaft adjuster in a construction with a wobble plate gear.
Advantageous improvements of the invention emerge from the claims, the description, and the drawings. The advantages named in the introduction of the description for features and combinations of several features are merely examples, without these having to be necessarily realized by embodiments according to the invention. Additional features are to be taken from the drawings—in particular, the illustrated geometries and the relative dimensions of several components to each other, as well as their relative arrangement and effective connection. The combination of features of different embodiments of the invention or of features of different claims is similarly possible deviating from the selected associations of the claims and is suggested with this reference. This also relates to features that are shown in separate drawings or are named in their description. These features can also be combined with features of different claims. Likewise, features listed in the claims can be left out for other embodiments of the invention.
Additional features of the invention emerge from the following description and the associated drawings, in which embodiments of the invention are shown schematically. Shown are:
In the figures, components that correspond with respect to form and/or function are to some extent provided with the same reference symbols.
The adjustment shaft 4 is driven by an electric motor 7 or is in active connection with a brake. The electric motor 7 is supported relative to the surroundings, for example, the cylinder head 8 or another engine-fixed part.
For the embodiment shown in
the contact surfaces between the drive conical gear wheel 20 and wobble plate 15,
the contact surface between the wobble plate 15 and driven conical gear wheel 18,
the bearing 19,
bearing element 14, and/or
bearing element 17.
Here, a continuous, cyclical, pulsing, or intermittent feed and/or forwarding of a lubricant via the lubricant channels is realized. Through the use of a feed recess 25 of the cylinder head 8, the lubricant is fed to a flow channel 26 of the camshaft 6, which communicates with a flow channel 27, which is formed with a hollow cylindrical shape between an inner casing surface 28 of the hollow shaft 16 and an outer casing surface 29 of the central screw 22. Through the use of radial boreholes 30 of the hollow shaft 16, the lubricant can emerge from the flow channel 27 outward in the radial direction and can be fed to the lubricating positions.
In contrast to the embodiment according to
The filter element 35 can be constructed, e.g., as
According to
For the embodiment shown in
Dead spaces according to the dead space 37 can be arranged at any position in the gear drive, as well as in the region of the camshaft, by which it can be achieved that important functional surfaces, for example, in the direct neighborhood of the dead spaces, are not “silted up” due to centrifuged contaminants in the gear drive. The centrifugal effect is amplified by an increase in the distance of the dead spaces from the longitudinal axis 21-21.
According to a first construction, the dead space has no additional outflow, so that centrifuged contaminant particles are deposited permanently in the dead space 37. According to the preferred construction shown in
For an alternative construction, contaminants are separated in such a way that the lubricant is guided in a flow channel with a labyrinth-like or zigzag-shape construction. Contaminant separation through such a labyrinth-like contaminant separator touches upon the different inertia of the lubricant and interfering particles in the lubricant. In particular, for high flow rates, a strong deflection of the lubricant flow can lead to the result that the particles are not deflected, but instead are deposited at the borders of the labyrinth. For the case that individual channels of the labyrinth are oriented in the radial direction, deposition in the labyrinth on surfaces on the outside in the radial direction can take place in such channels, as well as similarly in axial channels, due to the centrifugal force described above. An alternative or additional separating effect can be produced when the lubricant is decelerated and accelerated, wherein the lighter lubricant can be accelerated more easily, while contaminant particles remain behind.
In additional to generating the centrifugal effect due to rotation of the housing 9 or other parts of the camshaft adjuster 1, the centrifugal effect can be generated at least partially in such a way that the flow channels guiding the lubricant are oriented in a circular or spiral construction, so that a deposit can form on the outer boundaries of the flow channels just due to the movement of the lubricant through the curved flow channels.
Deviating from the embodiments shown in
Through the use of the diaphragms 41, 43 and throttles 42, 44, the volume flow to the camshaft adjuster is throttled. Additional throttling can be produced through the use of the filter element 35. Advantageously, the filter element is arranged in the flow direction upstream of the flow elements, so that the flow elements do not become blocked by particles or clogged over the course of time.
In addition to the use of flow elements with constant flow characteristics, a flow element that is continuous or that can be changed in steps can be used. The use of a flow element, whose flow effect is variable
The flow element is changed in such a way that, for example, the volume flow of the lubricant is held to a constant value independent of the temperature of the lubricant. It is also possible that the volume flow is increased or decreased due to an effect of the flow element in operating regions, in which there are higher or lower lubricant or cooling requirements.
For the construction of the flow elements in the form of throttles 42, 44 and diaphragms 41, 43, under some circumstances, embodiments are to be used, in which ring gaps or annular cross sections are used instead of boreholes with, for example, a circular cross sectional surface, because, under some circumstances, a borehole can be more easily blocked than a ring gap.
For the embodiment shown in
One part of the lubricant fed to the groove 48 via the borehole 45 and borehole 46 is led via an axial borehole 49 of the camshaft 6, which opens into the groove 48, and an axial borehole 50 of the housing 9 with a certain amount of overlap, but offset in the radial direction, in the inner space of the gear drive 2 to the lubricating positions, for example, to the bearing element 17, the bearing element 14, the rolling toothed connections of the wobble plate 15, and/or the bearing 19.
The other part of the lubricant fed to the groove 48 is led via a flow channel 51 with a circular ring-shaped cross section and formed between the inner casing surface of the hollow shaft 16 and the outer casing surface of the central screw 22 to at least one radial borehole 52 to a lubricating position, for example, the bearing position 17 or in the inner space of the gear drive 2. The groove 48 is constructed with a radial projection, which extends over the borehole 49, so that a peripheral, ring-shaped dead space 37 is formed on the outside in the radial direction. Between the boreholes 49, 50, a transfer region 53 can be formed in the shape of a recess, a radial groove, or the like, in order to allow transfer between the boreholes 49, 50 that are offset relative to each other in the radial direction. In the form of the boreholes 49, 50 that are not aligned with each other, for a partial overlap of the boreholes, a kind of diaphragm can be formed with a small transfer cross section or diaphragm cross section, although the boreholes 49, 50 can be produced with relatively large diameters and thus with rough tools.
For a construction that otherwise corresponds to
For a construction that otherwise corresponds to the embodiments described above, the camshaft 6 according to
In a modified construction, the flow element 59 can be tensioned outward, for example, in the radial direction against the borehole 46, wherein, in this case a ring gap 60 is formed between the inner surface of the flow element and the central screw. Also, a positive-fit holding of the flow element 59, for example, in a suitable groove of the camshaft or the central screw, is conceivable. An arbitrary construction of the contours of the flow element 59 in the region of the ring gap 60 is possible for influencing the flow ratios, for example, with stepped transitions or continuous transitions.
For the embodiment shown in
The camshaft 6 is supplied with a lubricant from a lubricant gallery of the cylinder head 8. The transition of the lubricant from the engine-fixed cylinder head 8 to the rotating camshaft 6 is realized usually by known rotary transmitters. This typically involves a ring groove 64 of the outer casing surface of the camshaft 6. The ring groove 64 is enclosed by a corresponding cylindrical casing surface 65 of the cylinder head 8, to which a pass borehole 66 oriented in the axial direction toward the ring groove 64 leads out of the lubricant gallery. The pass borehole 66 can pass through the casing surface 65, as shown in
A rotary transmitter can be arranged in a radial bearing for the camshaft 6 or on a separate shoulder. For the latter, however, due to the usually larger radial gap, often sealing rings 67, 68, for example, a steel sealing ring, cast-iron sealing ring, or plastic sealing ring, are required. In an arrangement of the rotary transmitter in a radial bearing of the camshaft 6 it is to be taken into account that the bearing width is reduced by the width of the ring groove.
In another embodiment, ring grooves can be constructed fixed to the cylinder head, for example, in the bearing, the bearing bridge, or an installed bearing bushing. In the camshaft, no ring grooves 64 are required.
The use of a rotary transmitter described above causes a continuous flow of lubricant from the cylinder head 8 into the camshaft 6 due to the peripheral ring groove and the radial boreholes 69, which connect the ring groove 64 to the borehole 46.
For a special construction, the pass borehole 66 and the ring groove 64 are arranged offset relative to each other in the axial direction, by which, in the transfer of the lubricant from the pass borehole 66 to the ring groove 64, a type of throttle is created, whose opening cross section becomes smaller the greater the offset in the axial direction between the pass borehole 66 and ring groove 64. A throttle effect can also be achieved for a relatively large diameter of the pass borehole 66 and a larger width of the ring groove 64, so that no small boreholes or grooves, which are sensitive to contaminants and production, have to be created.
According to another special construction, lubricant is fed via a cyclical lubricant supply. In such a case, the ring groove 64 is left out, so that a lubricant connection between the pass borehole 66 and the boreholes 69 is given only for rotational positions of the camshaft 6, for which the boreholes 66, 69 align with each other or overlap. If increased transfer times are desired, then the transition region between the pass borehole 66 and borehole 69 of the cylinder head 8 or the casing surface of the camshaft 6 can have a groove running through a partial extent, so that a transfer from the pass borehole 66 to the borehole 69 is possible as long as these boreholes 66, 69 are connected to each other by the groove. In addition, through the construction of the width profile of the groove, there can be a variable transfer of the lubricant. Thus, a volume flow and mass flow of the lubricant can be given structurally and cyclically. Furthermore, a pulsing lubricant flow can be realized, which results in fluctuations in pressure that can be used, for example, for better mixing and wetting of the lubricating positions with the lubricant. Furthermore, through pulsing lubricant flows, the risk of blockages can be reduced, for example, for diaphragms or throttles. If such lubricant pulses lead to pulse oscillations in the lubricant cycle, then a non-return valve can be arranged in the lubricant circuit, in particular, in the region of the cylinder head 8, in the region of the camshaft, and/or in the gear drive.
For the embodiment shown in
In addition to the structural measures for constructing the flow cross sections in the cylinder head and also in the camshaft, the flow ratios in the lubricant circuit in the gear drive can be influenced. Here, the supply borehole can be throttled through the use of a throttle or diaphragm. Alternatively or additionally, the throttling of the discharge through a rear-side closing of the gear drive, for example, with a sheet-metal cover, is possible, which forms, together with the adjustment shaft, a ring-shaped gap, in particular, with a gap height in the range from 0.1 to 2 mm.
In addition, it is possible to use bearings in the gear drive, which are equipped with sealing elements. According to
According to another construction of a camshaft adjuster 1, the outer casing surface of the housing 9 has recesses or windows 77, which can be distributed uniformly or non-uniformly in the peripheral direction, cf.
In addition, through the arrangement of the openings 77, 78 of the gear housing, the lubricant can be sprayed directly onto a toothed section or other lubricating positions. It is also conceivable that the spraying with lubricant is combined with the lubricant supply of other engine components, for example, a chain or a tensioner. It is also conceivable that a point or a surface outside of the gear drive 2 is sprayed with the lubricant. Lubrication is then guaranteed through the rebounding or reflected lubricant or a lubricant mist generated in this way.
According to an alternative construction, a lubricant supply can be realized by the lubricant mist, which is already present in a timing case and which can penetrate into the camshaft adjuster through the openings 77, 78.
In another construction of a lubricant supply according to
To reliably guarantee functioning for lubrication with a lubricant mist, mist lubricant droplets, or with a lubricant stream, even at low temperatures of the lubricant or for a cold start, the lubricating positions, for example, slide bearings and/or toothed sections, are to be equipped with emergency-running properties. Such emergency-running properties can be guaranteed, for example
In particular, the lubricant reservoirs are provided by microscopically or macroscopically small pockets at the lubricating positions, in which lubricant can be stored for a cold start or for low lubricant temperatures. Better emergency-running properties can also be provided, advantageously, when roller bearings are provided at the bearing positions as much as possible.
Furthermore, for lubrication, oil dripping from an oiled traction element (timing chain) can also be used, which passed through an opening of the housing. Under some circumstances, the traction element is lubricated by wobble or spray oiling or by stripping oil from oiled chain tensioners or deflection rails. A part of the oil supplied by the chain can drops above the drive wheel (chain wheel) of the gear drive and can thus be led into openings of the gear drive lying underneath. In addition, it is possible to feed oil through the capillary effect to the gear drive or to drip positions lying above the gear drive. It is also possible that oil is “blown,” for all practical purposes, to the lubricating position, by air currents resulting, e.g., from the drive movement of the control drive or adjustment parts.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 059 860.9 | Dec 2005 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2006/068964 | 11/28/2006 | WO | 00 | 7/2/2008 |
