Hydraulic camshaft adjuster and method for operating a hydraulic camshaft adjuster
阅读说明:本技术 液压凸轮轴调节器和用于运行液压凸轮轴调节器的方法 (Hydraulic camshaft adjuster and method for operating a hydraulic camshaft adjuster ) 是由 格哈德·沙伊迪希 约亨·蒂伦 伊诺·施米特 于 2018-06-18 设计创作,主要内容包括:本发明涉及一种用于调节内燃机的换气阀的调节时间的液压凸轮轴调节器(1),具有定子(2),它能够与内燃机的曲轴同步转动,还具有一个相对于定子(2)可扭转布置的转子(3),它能够与凸轮轴同步转动,其中,在定子(2)上设置有多个腹板(6),它们将定子(2)和转子(3)之间的环形空间(7)划分成多个压力室(8),其中,转子(3)具有转子轮毂(4)和多个从转子轮毂(3)出发径向朝外延伸的叶片(5),这些叶片将压力室(8)划分成两组分别能够加载流入或流出压力介质循环的压力介质(19)的具有不同作用方向的工作室(9、10),还具有用于将转子(3)锁定在中心位置上的中心锁定机构(11),其中,液压凸轮轴调节器(1)在端侧(20、21)被盖(17、18)部分地封闭,其中,在其中一个盖(17、18)中构造有用于储存压力介质(19)的存储库(14),其中,盖(17、18)具有溢流口(23),压力介质(19)能够通过这个溢流口沿轴向方向从液压凸轮轴调节器(1)溢出,并且其中,存储库(14)相对于溢流口(23)按如下方式设计尺寸,即,使得在液压凸轮轴调节器(1)停机的情况下,还在存储库(14)中保留有压力介质池(25),它在液压凸轮轴调节器(1)启动时确保了对中心锁定机构(11)的止回阀(28)的压力介质供应。本发明此外还涉及一种用于运行这种液压凸轮轴调节器(1)的方法。(The invention relates to a hydraulic camshaft adjuster (1) for adjusting the adjustment times of gas exchange valves of an internal combustion engine, having a stator (2) which can be rotated synchronously with the crankshaft of the internal combustion engine and having a rotor (3) which is arranged so as to be rotatable relative to the stator (2) and which can be rotated synchronously with the camshaft, wherein the stator (2) is provided with webs (6) which divide an annular space (7) between the stator (2) and the rotor (3) into a plurality of pressure chambers (8), wherein the rotor (3) has a rotor hub (4) and a plurality of blades (5) which extend radially outward from the rotor hub (3) and divide the pressure chambers (8) into two groups of working chambers (9, 10) which can be charged with a pressure medium (19) which circulates in or out, respectively, and which have different directions of action, and a central locking mechanism (11) for locking the rotor (3) in a central position, wherein the hydraulic camshaft adjuster (1) is partially closed at the end faces (20, 21) by covers (17, 18), wherein a storage reservoir (14) for storing a pressure medium (19) is formed in one of the covers (17, 18), wherein the cover (17, 18) has an overflow opening (23) through which the pressure medium (19) can overflow from the hydraulic camshaft adjuster (1) in the axial direction, and wherein the storage reservoir (14) is dimensioned relative to the overflow opening (23) in such a way that, in the event of a standstill of the hydraulic camshaft adjuster (1), a pressure medium reservoir (25) remains in the storage reservoir (14) which, when the hydraulic camshaft adjuster (1) is started, ensures a pressure medium supply to a non-return valve (28) of the central locking mechanism (11). The invention further relates to a method for operating such a hydraulic camshaft adjuster (1).)
1. Hydraulic camshaft adjuster (1) for adjusting the adjustment time of a gas exchange valve of an internal combustion engine, having
-a stator (2) which can be rotated synchronously with a crankshaft of the internal combustion engine, and a rotor (3) which is arranged so as to be rotatable relative to the stator (2) and which can be rotated synchronously with a camshaft, wherein
-providing a plurality of webs (6) on the stator (2), which divide an annular space (7) between the stator (2) and the rotor (3) into a plurality of pressure chambers (8), wherein
-the rotor (3) has a rotor hub (4) and a plurality of blades (5) extending radially outwards from the rotor hub (3) and dividing the pressure chamber (8) into two groups of working chambers (9, 10) having different directions of action and each being able to be loaded with a pressure medium (19) circulating in or out of the working chambers,
-a central locking mechanism (11) for locking the rotor (3) in a central position, wherein
The hydraulic camshaft adjuster (1) is partially closed at the end faces (20, 21) by covers (17, 18), wherein
-a storage reservoir (14) for storing a pressure medium (19) is constructed in one of the covers (17, 18), and wherein
The cover (17, 18) has an overflow (23) through which the pressure medium (19) can overflow in the axial direction from the hydraulic camshaft adjuster (1),
it is characterized in that the preparation method is characterized in that,
-the storage reservoir (14) is dimensioned relative to the overflow (23) in such a way that, in the event of a standstill of the hydraulic camshaft adjuster (1), a pressure medium reservoir (25) remains which ensures a pressure medium supply to a non-return valve (28) of the central locking mechanism (11) when the hydraulic camshaft adjuster (1) is started up, wherein
-a check valve (28) for supplying the central locking mechanism (11) with pressure medium is arranged on a first pitch diameter (30) and a check valve (27) for supplying the working chamber (9, 10) with pressure medium is arranged on a second pitch diameter (29), wherein the first pitch diameter (30) is larger than the second pitch diameter (29).
2. Hydraulic camshaft adjuster (1) according to claim 1, characterized in that the cover (17, 18) configured with a storage reservoir (14) for storing pressure medium (19) is configured without a dead volume (22).
3. The hydraulic camshaft adjuster (1) as claimed in one of claims 1 or 2, characterized in that the stator (2) is bounded by a locking cover (17) and a storage reservoir cover (18), wherein the storage reservoir (14) is constructed on the storage reservoir cover (18).
4. Hydraulic camshaft adjuster (1) according to one of the preceding claims, characterized in that a blocking element (31) is constructed on one of the covers (17, 18), which blocks the flow of pressure medium (19) into the dead volume (22).
5. The hydraulic camshaft adjuster (1) as claimed in claim 4, characterized in that a pocket (32) is formed on the storage housing cover (18).
6. Hydraulic camshaft adjuster (1) according to claim 5, characterized in that a blocking element (31) which blocks the flow of pressure medium (19) into the pocket (32) is provided on one of the covers (17, 18).
7. The hydraulic camshaft adjuster (1) as claimed in one of claims 5 or 6, characterized in that the dead volume (22) is formed by an opening for a check valve access channel and/or is formed as a recess for a screw connection.
8. Hydraulic camshaft adjuster (1) according to one of claims 1 to 7, characterized in that the storage reservoir (14) on one of the covers (17, 18) has a geometry differing from a cylinder, so that the dead volume remaining with pressure medium which cannot be used to supply the central locking mechanism (11) during the start-up phase is reduced.
9. Method for operating a hydraulic camshaft adjuster (1) according to one of claims 1 to 8, characterized in that, when the internal combustion engine is switched off, pressure medium (19) accumulates in the storage reservoir (14), and when the internal combustion engine is restarted, the pressure medium (19) is thrown from the storage reservoir (14) by centrifugal force onto the substantially annular outer starting volume, wherein a check valve (28) for supplying the central locking mechanism (11) is arranged in the region of the hydraulic camshaft adjuster (1) covered by the substantially annular starting volume.
Technical Field
The invention relates to a hydraulic camshaft adjuster and to a method for operating a hydraulic camshaft adjuster according to the preambles of the independent claims.
Background
Hydraulic camshaft adjusters are used in internal combustion engines to match the load state of the internal combustion engine in order to increase the efficiency of the internal combustion engine. From the prior art, many hydraulic camshaft adjusters operating according to the vane principle are known. These camshaft adjusters usually have, in their basic configuration, a stator which can be driven by the crankshaft of the internal combustion engine and a rotor which is connected in a rotationally fixed manner (drehfest) to the camshaft of the internal combustion engine. An annular space is provided between the stator and the rotor, which annular space is divided by a radially inwardly projecting projection connected in a rotationally fixed manner to the stator into a plurality of working chambers, which are each divided by a vane projecting radially outward from the rotor into two pressure chambers. Depending on the loading of the pressure chamber with hydraulic pressure medium, the position of the rotor relative to the stator can be adjusted so that the relative position of the camshaft relative to the crankshaft can be adjusted in the "advance" or "retard" direction. Hydraulic camshaft adjusters with a central locking mechanism are known, in which the rotor can be locked in a central position in addition to the respective end position, in order in particular to facilitate the starting of the engine. However, in special cases, for example in the event of a stall of the internal combustion engine, the locking device cannot lock the rotor properly, and the camshaft adjuster must be operated with the rotor unlocked in the subsequent starting phase. However, since some internal combustion engines have poor starting performance when the rotor is not locked in the central position, the rotor must be twisted into the central locking position during the starting phase and then locked. Hydraulic camshaft adjusters with a reservoir volume are also known, in which the hydraulic working chambers for adjusting the rotor are supplied from the reservoir volume by a pressure medium pump in the event of an insufficient supply, in order to avoid air being sucked into the respective working chamber and additionally to utilize the torque of the camshaft drive. Such hydraulic camshaft adjusters are known as intelligent phasers. If the hydraulic camshaft adjuster has not only a central locking mechanism but also a volume accumulator, this camshaft adjuster is also intelligently locked.
The hydraulic camshaft adjuster with a volume accumulator for pressure medium has a significantly lower throughput of pressure medium and a higher adjustment speed than conventional hydraulic camshaft adjusters. DE 102012201558 a1 discloses a hydraulic camshaft adjuster with a plurality of volume accumulators, wherein the volume accumulators are formed in the hollow space of the rotor. A hydraulic camshaft adjuster with a plurality of volume accumulators for supplying hydraulic oil into the working chambers of the camshaft adjuster is known from DE 102012201556 a1, wherein the volume accumulators are formed in webs of the stator, which webs separate the working chambers of the camshaft adjuster from one another. In this case, a non-return valve is provided on the volume accumulator in order to prevent uncontrolled outflow of hydraulic oil into the working chamber of the camshaft adjuster. Hydraulic camshaft adjusters are also known in which a volume accumulator is formed in the cover of the hydraulic camshaft adjuster.
DE 102016218793 a1 shows a camshaft adjuster having a drive element and an output element which can be rotated through a certain angle and which can be connected to a camshaft, wherein a pressure-applicable working chamber is formed between the drive element and the output element for rotation of the output element relative to the drive element, wherein the camshaft adjuster has a volume accumulator for collecting hydraulic medium, wherein the volume accumulator feeds the hydraulic medium to the working chamber to which a negative pressure is applied via a non-return valve, for which purpose the negative pressure in the working chamber opens the non-return valve and the non-return valve is arranged in an axial position between the working chamber and the volume accumulator, wherein the volume accumulator is formed by a cover element which is connected to the drive element in a rotationally fixed manner.
However, the known solutions have the disadvantage that they are either very complicated and therefore relatively expensive or that under certain (unfavorable) operating conditions it is not ensured that the support chamber for adjusting the camshaft adjuster into the central position is sufficiently supplied with oil. Disadvantageously, the pressure medium stored in the storage reservoir during the engine shutdown is limited to a certain filling level due to overflow on the control magnets of the hydraulic camshaft adjuster. Since during operation centrifugal forces are required in order to keep the oil in the entire annular reservoir in a surrounding manner, a large part of the oil flows out of the reservoir via the overflow in the idle state. Thus, only a small amount of oil can be supplied at the start. It is therefore not possible to ensure that the bore hole for supplying the working chamber and/or the central locking device with oil is always sufficiently covered by the pressure medium and that air is reliably prevented from being sucked in. This is critical in particular during the starting of the internal combustion engine, since the following requirements are present at the start: the pressure medium is accelerated into the surrounding track of the cover and thus it is ensured that the pressure medium covers the non-return valve for supplying the support chamber with pressure medium in the radial direction.
Disclosure of Invention
The object of the present invention is to provide a hydraulic camshaft adjuster with a central locking portion, which overcomes the disadvantages of the solutions known from the prior art and in particular improves the oil supply during the starting phase, so that a functionally reliable starting of the engine is ensured.
According to the invention, the object is achieved by a hydraulic camshaft adjuster for adjusting the adjustment times of gas exchange valves of an internal combustion engine, having a stator which can be rotated synchronously with a crankshaft of the internal combustion engine and a rotor which is arranged so as to be rotatable relative to the stator and which can be rotated synchronously with a camshaft. In this case, a plurality of webs are arranged on the stator, which webs divide the annular space between the stator and the rotor into a plurality of pressure chambers. The rotor has a rotor hub and a plurality of blades extending radially outward from the rotor hub, which divide the pressure chamber into two groups of working chambers having different directions of action, which can be charged with a pressure medium circulating in or out of the working chambers, respectively. The hydraulic camshaft adjuster furthermore has a locking mechanism for locking the rotor in the central position. In this case, the hydraulic camshaft adjuster, in particular the stator of the hydraulic camshaft adjuster, is at least partially closed by a cover on at least one end side, preferably on both end sides. A reservoir for storing pressure medium is formed in one of the covers, wherein the cover has an overflow opening, through which the pressure medium can escape from the hydraulic camshaft adjuster in the axial direction. The reservoir is dimensioned relative to the overflow in such a way that, in the event of a standstill of the hydraulic camshaft adjuster, a pressure medium reservoir remains in the reservoir, which ensures at least the supply of pressure medium to the check valve of the central locking mechanism when the hydraulic camshaft adjuster is restarted.
The proposed hydraulic camshaft adjuster makes it possible to rotate the rotor from any desired position to the center position after the internal combustion engine has started, so that the engine start and the subsequent warm-up phase of the internal combustion engine are facilitated. In order to rotate the rotor into the central position, the oil supply to the respective working chamber is effected from a storage reservoir of the hydraulic camshaft adjuster and by means of a pressure medium pump. The amount of pressure medium that can escape through the overflow opening is only of such a size that the remaining amount of pressure medium is sufficient to completely cover the check valve of the center lock at startup with pressure medium and to prevent air from being sucked in through the check valve. This allows the rotor to be twisted into the central position better after a cold start or after restarting the internal combustion engine.
According to the invention, it is provided that the check valve for supplying the center locking mechanism with pressure medium is arranged on a first pitch circle and the check valve for supplying the working chamber with pressure medium is arranged on a second pitch circle diameter, wherein the first pitch circle diameter is larger than the second pitch circle diameter. After starting the engine, the availability of the lock-up function has a higher priority than the smart phase function. It is therefore advantageous that the check valve for the locking function is supplied with pressure medium more quickly than the check valve for the working chamber of the smart phase function after the engine has started. By arranging the check valve for the locking chamber on a larger pitch circle diameter than the check valve for the other control chamber, a preferred oil supply to the locking chamber is achieved, as a result of which the rotor is rotated into the central locking position according to the operating principle of the hydraulic ratchet and can be locked there.
The hydraulic camshaft adjuster specified in the independent claim can be advantageously modified and improved by the features recited in the dependent claims.
In a preferred embodiment of the invention, it is provided that the cover, which is designed with a storage reservoir for storing pressure medium, is designed without a dead volume. Dead volumes are here defined as areas in which the pressure medium cannot pass from the dead volumes to the non-return valve due to centrifugal forces and is thus trapped in these dead volumes. This prevents the pressure medium from accumulating in one of the dead volumes during the start-up and thus from being pressed outward by centrifugal forces. The reduction of the dead volume makes it possible to improve the oil supply to the check valve, in particular during the start-up phase of the hydraulic camshaft adjuster.
According to an advantageous embodiment of the invention, it is provided that the stator is delimited at the end by a locking cover and a storage compartment cover, wherein the storage compartment is formed on the storage compartment cover.
Because of the necessary recesses in the locking mechanism and the locking cover, there are relatively many undercuts on this cover, which may constitute dead volumes. It is therefore advantageous that the storage library is arranged in a storage library cover.
It is alternatively advantageous if the locking cover and the storage-reservoir cover are combined in one part, so that the shortest possible flow path for the pressure medium to the locking mechanism can be ensured.
In a preferred embodiment of the hydraulic camshaft adjuster, it is provided that a blocking element is formed on the cover, which is formed with the reservoir, which blocks the flow of hydraulic medium into the dead volume of the hydraulic camshaft adjuster. The flow of the hydraulic medium into the dead volume can be blocked by the blocking element, so that the risk of accumulation of the pressure medium in the dead volume is reduced.
In this case, it is particularly preferred if the blocking element is formed in or in front of the pocket. The pocket in one of the covers makes it possible to create free space for other components, in particular for screw connections or valve passages. By this blocking element, such a pocket is filled or the inflow opening into the pocket is covered, so that a hydraulic connection from the reservoir to the dead volume or a hydraulic separation of the dead volume from the reservoir is prevented.
According to an advantageous development of the hydraulic camshaft adjuster, it is provided that the dead volume is formed by an opening for the check valve inlet channel and/or as a recess for a screw connection. Screw connections and mounting glands are typical examples of dead volumes on hydraulic camshaft adjusters, in which pressure medium can accumulate when the engine is shut down or at the beginning of a starting process. It is therefore provided that the respective cover is designed in such a way that the inflow into these dead volumes is prevented.
According to a preferred embodiment of the invention, it is provided that the storage reservoir on the cover has a geometry that differs from the cylinder, so that the dead volume of pressure medium remaining in the starting phase, which cannot be used for supplying the central locking mechanism with oil, is reduced. The non-cylindrical storage space allows a corresponding area to be left on the hydraulic camshaft adjuster, in particular on the stator, so that it is avoided that the storage space coincides with the recess required for the drilling or assembly of the screw connection. In this way, it is possible to use all of the pressure medium remaining in the reservoir when restarting the internal combustion engine, so that the check valve is supplied with pressure medium and air intake is avoided.
According to the invention, a method for operating a hydraulic camshaft adjuster according to the invention is proposed, wherein, when the internal combustion engine is switched off, pressure medium is collected in a storage reservoir and, when the internal combustion engine is restarted, the pressure medium is thrown out of the storage reservoir by centrifugal force into a substantially annular outer starting volume, wherein a check valve for supplying a locking mechanism is arranged in the region of the hydraulic camshaft adjuster, which is covered by the substantially annular starting volume. Air is thereby prevented from being sucked into the working chamber for rotating the rotor to the center locking position, and it is ensured that the rotor is reliably rotated to the center locking position in accordance with the operating principle of the hydraulic ratchet.
The various embodiments of the invention mentioned in the present application can advantageously be combined with one another, unless otherwise stated in individual cases.
Drawings
The invention will be explained in more detail below with the aid of preferred embodiments and the accompanying drawings. Identical components or components having the same function are provided with the same reference numerals. In the figure:
fig. 1 shows an embodiment of a hydraulic camshaft adjuster according to the invention in a sectional view;
fig. 2 shows a three-dimensional view of the cover of the hydraulic camshaft adjuster according to the invention and the pressure medium distribution in different operating states;
fig. 3 shows a sectional view of the hydraulic camshaft adjuster and the pressure medium reservoir according to the invention when the internal combustion engine is switched off;
fig. 4 shows a further sectional view of the hydraulic camshaft adjuster according to the invention after the internal combustion engine has started and the pressure medium distribution;
fig. 5 shows a further sectional view of the hydraulic camshaft adjuster according to the invention, in order to show the dead volume; and
fig. 6 shows a further sectional view of the hydraulic camshaft adjuster according to the invention.
Detailed Description
Fig. 1 shows an exemplary embodiment of a hydraulic camshaft adjuster 1 according to the invention for adjusting the valve timing of an internal combustion engine. The hydraulic camshaft adjuster 1, which is schematically illustrated in fig. 1, is designed in a known manner as a vane adjuster and comprises a
In principle, when the hydraulic camshaft adjuster 1 is in the normal operating state, the angle of rotation of the camshaft relative to the crankshaft is adjusted in such a way that the first group of working
A
Fig. 6 shows a further sectional view of the hydraulic camshaft adjuster 1 according to the invention. Here, the hydraulic connection of the
Fig. 2 shows a three-dimensional perspective view of the
Fig. 3 shows a sectional view of a hydraulic camshaft adjuster 1 according to the invention. Here it can be seen that the
Fig. 4 shows a further sectional view of the hydraulic camshaft adjuster 1 according to the invention, wherein the hydraulic camshaft adjuster 1 rotates after the internal combustion engine has started with the number of revolutions of the camshaft, i.e. half the number of revolutions of the crankshaft. The
Since, according to the invention, the hydraulic camshaft adjuster 1 can no longer rotate the
Fig. 5 shows a further sectional view through a hydraulic camshaft adjuster 1 according to the invention. Here, a
In the hydraulic camshaft adjuster 1 according to the invention, it is therefore possible to rotate the
List of reference numerals
1 Hydraulic camshaft adjuster
2 stator
3 rotor
4 rotor hub
5 blade
6 web
7 annular space
8 pressure chamber
9 working chamber
10 working chamber
11 center locking mechanism
12 locking chute
13 locking pin
14 storage warehouse
15 pressure medium pump
16 reserve container
17 locking cover
18 storage library cover
19 pressure medium
20 first end side
21 second end side
22 dead volume
23 overflow outlet
24 support chamber
25 pressure medium pool
26 into the borehole
27 check valve
28 check valve
29 first pitch diameter
30 second pitch diameter
31 blocking element
32 pocket part
33 sealing cover
34 oil level in continuous operation of engine
35 oil level during start-up
36 screw