EP1164255A1 - Apparatus for changing of phase angle between a cam shaft and a driving wheel of an internal combustion engine - Google Patents

Abstract

An opening (62) connecting with the oil channel (61) is located between two pressure chambers (22a,24a), in or on the sectored wheel (12). Its passage between the pressure chambers is controlled as a function of the position to which the inner component (4) is adjusted.

Description

The invention relates to a device for the relative rotation angle adjustment Camshaft of an internal combustion engine to a drive wheel according to the genus of Main claim.

From DE 196 23 818 A1 a generic device is known in which with With the help of a locking element arranged in the rotor of the camshaft adjuster the camshaft adjuster can be locked in one end position. About to Locking element leading oil lines, the locking element from its Locking position can be transferred to an unlocked position. Is the The camshaft adjuster can be unlocked by hydraulic adjustment of the rotor relative to the drive wheel of the camshaft, the timing of the intake and exhaust valves a camshaft can be changed in the desired manner. Because of the Camshaft arranged cams, which have corresponding cam followers, e.g. Bucket tappets that open and close inlet and outlet valves are placed on the rotor of the camshaft adjuster, since it is connected to the camshaft in a rotationally fixed manner, Transfer alternating torques (rising - running cams). This from the Alternating torques caused by the camshaft lead to periodic changes in the rotational position of the rotor against the stator of the camshaft adjuster, which in certain Operating states of the internal combustion engine, especially in idle mode, to one lead to undesired adjustment of the intake and exhaust times of the camshaft if that Locking element is already unlocked. Furthermore, when switching off the Internal combustion engine the risk of continuing due to the locking element the locking element of the camshaft adjuster is not present can be locked.

In contrast, it is the object of the invention to provide a generic device for relative rotation angle adjustment of a camshaft to its drive wheel to that effect improve that despite certain operating conditions in which the adjustment unit is not more or not yet active, a safe and reliable locking of the Camshaft adjuster by the locking element mentioned above.

This object is achieved by the features of the main claim.

Through an opening arranged between two pressure chambers of a cellular wheel, which with an oil channel provided for unlocking the locking element in the rotor is connected and their cross section depending on the rotational position of the rotor is controlled, on the one hand, the locking element via the one pressure chamber be unlocked, while at a second, in particular by alternating moments Camshaft caused the rotor to change its rotational position across the other pressure chamber Hydraulic relief of the oil channel takes place, so that the locking element can be safely brought back into a locked position. Even when switching off the Internal combustion engine with the help of the opening leading to the locking element Oil channel relieved hydraulically, so that it is ensured that even when the Internal combustion engine the locking element is locked again.

Further advantages and advantageous developments of the invention result from the Subclaims and the description.

Two embodiments of the invention are in the following description and Drawings explained in more detail.

Fig. 1

einen Längsschnitt durch die Verstelleinheit,

Fig. 2

einen Schnitt entlang der Linie II - II in Fig. 1,

Fig. 3

einen Schnitt entlang der Linie III - III in Fig. 1,

Fig. 4 - Fig. 9

verschiedene Betriebszustände der Verstelleinheit in Verstellrichtung,

Fig. 10 - Fig. 14

verschiedene Betriebszustände der Verstelleinheit in Rückstellrichtung,

Fig. 15 - Fig. 20

verschiedene Betriebszustände der Verstelleinheit in Verstellrichtung nach einem zweiten Ausführungsbeispiel,

Fig. 21 - Fig. 25

verschiedene Betriebszustände der Verstelleinheit in Rückstellrichtung nach einem zweiten Ausführungsbeispiel.

Show it

Fig. 1

a longitudinal section through the adjustment unit,

Fig. 2

2 shows a section along the line II-II in FIG. 1,

Fig. 3

2 shows a section along the line III-III in FIG. 1,

Fig. 4-9

different operating states of the adjustment unit in the adjustment direction,

10 - 14

different operating states of the adjustment unit in the reset direction,

Fig. 15-20

different operating states of the adjustment unit in the adjustment direction according to a second embodiment,

Fig. 21-25

Different operating states of the adjustment unit in the reset direction according to a second embodiment.

Description of the embodiments

In the drawing, the camshaft of an internal combustion engine is shown schematically at 2 indicated, at the free end of the rotor, hereinafter referred to as inner part 4, an adjusting device 6 is arranged in a rotationally fixed manner. The inner part 4 is in this Embodiment provided with five radially arranged webs 8a to 8e, the from a hub 10 of the inner part 4 go out. The web 8a has two on its side faces Control edges 9a and 9b, whose function will be explained in more detail later. The Inner part 4 is surrounded in the region of its webs 8a to 8e by a cellular wheel 12 which is provided with five inwardly projecting radial webs 14a to 14e. On the The outer circumference of the cellular wheel 12 is, for example, as a chain or toothed belt wheel Trained drive wheel (not shown) for driving the camshaft 2 arranged. The cellular wheel 12 representing the stator of the adjusting unit 6 is opened its end facing the camshaft 2 is closed off by a disk 16, which is rotatably and sealingly guided on the hub 10 of the inner part 4. The opposite end face of the cellular wheel 12 is also from a disk 18th closed, the disks 16 and 18 and the cellular wheel 12 not over screws shown are firmly connected. The in the webs 14a to 14e Through holes 20 provided in the cellular wheel 12 serve for receiving or Guide these mounting screws. Through the webs 14a to 14e of the cellular wheel 12 five cells are delimited by the disks 16 and 18 in the axial direction formed by the webs 8a to 8e of the inner part 4 in two pressure chambers 22a to 22e and 24a to 24e are divided. The inner part 4 and the rotatable on this guided cell wheel 12 are connected to each other by a screw 25. To do so the hub 10 has a threaded central bore 26.

The pressure chambers 22a to 22e are in each case via a radial bore 28a to 28e Hub 10 of the inner part 4 connected to an annular space 30 which is between the Fixing screw 25 for the adjustment unit 6 and the wall sections of the in of the hub 10 provided central bore 26, wherein the annular space 30th is closed at the end by the head 31 of the screw 25.

The annular space 30 is via a plurality of bores made radially in the camshaft 2 32 connected to an annular groove 34 arranged on the outer circumference of the camshaft 2. The pressure spaces 24a to 24e are connected via radial bores 36a to 36e with an am Outer periphery of the camshaft 2 arranged annular groove 38 connected via an axial in the camshaft 2 arranged bore 40 to another, also on The outer circumference of the camshaft 2 leads the annular groove 42.

The two ring grooves 34 and 42 are each via a acting as a rotary union Camshaft bearing 44 connected to a control line A and B. The two Control lines A and B are with, for example, a 4/2 proportional control valve trained control valve 48 connected. This control valve 48 is also with a pressure medium pump 49 and an oil tank 50 connected. Immediately behind the Pressure medium pump 49, a check valve 51 is arranged in the pressure line P. in the The present exemplary embodiment is the adjusting unit 6 with its in FIGS. 1 to 3 provided end position for the adjustment of an exhaust camshaft, wherein the cellular wheel 12 is driven counterclockwise while the Inner part 4 adjusted clockwise in the direction of "late" opening of the exhaust valves can be.

To lock the inner part 4 with respect to the cellular wheel 12 in a according to the Figures 1 to 3 shown end position of the adjusting unit 6 is a in the web 8a Bore 52 provided in the one locking element, in the following as Designated locking pin 53 is arranged. The bore 52 is as Stepped bore formed, wherein in the larger bore section 54 with a Ring shoulder 55 provided part of the locking pin 53 is guided. The Locking pin 53 has a bore 56 in which a compression spring 57 is arranged between the bottom of the bore 56 and one on the disk 18 supporting plastic disk 58 arranged in the bore section 54 is clamped. The plastic disc 58 has a central opening 59, which with a channel 60 leading back to the tank 50 is connected, via which when moving of the locking pin 53 against the spring force of the compression spring 57 in the bore 52 located leakage oil is returned to the tank 50. The channel 60 is thereby formed by a groove arranged in the web 8a, through the cover 18 except for one Opening 46 is closed.

A radial leads from the bottom region of the bore section 54 of the bore 52 Through hole 61 to the end face of the web 8a. Between the two webs 14a and 14e is an opening formed on the inside of the cellular wheel 12 62, via which, as will be described in more detail later, one by the Ring shoulder 55, the inner wall of the bore 54 and the outer wall of the Locking pin 53 formed annular chamber 100 oil is supplied. In the disc 16 an elongated hole 63 is made, in which the locking pin 53 is locked can be. The elongated hole 63 extends in the radial direction, so that at a slightly different from the end position of the adjusting unit 6 rotary position of the inner part 4 a locking of the locking pin 53 is already possible. In the Washer 16 is behind slot 63 with slot 63 connected blind hole 64 arranged whose diameter is smaller than that Diameter of the locking pin 53 is. To the blind hole 64 leads with Pressure chamber 22a connected channel 65, via which, as will be described in more detail later, an end face 66 of the locking pin 53 in certain operating states Oil pressure for unlocking the locking pin 53 is applied.

A complete adjustment process is described below with reference to FIGS Adjustment unit 6 described:

Fig. 4

The internal combustion engine is out of operation, i.e. at standstill. The Locking pin 53 is in the locked position, i.e. he's through that Compression spring 57 locked in the bore 63 of the disc 16. This is the Adjustment unit 6 in its end position, that of an "early" opening or closing time the exhaust valves of the internal combustion engine actuated via cams and cam followers corresponds. Remains during the starting process until the idling speed is reached the engine oil pressure, which is used to adjust the inner part 4 relative to the cellular wheel 12 Adjustment unit 6 is used, below the unlocking minimum pressure. The Control valve 48 is de-energized, so the pressure lines via control line A. 24a to 24e oil supplied. At this angular position of the inner part 4 relative to Cellular wheel 12 gives the left control edge 9a of the web 8a the connection of the Pressure chamber 24a to pocket 62 free, so that the bore 61 of the annular chamber 100th Oil can be supplied while the right control edge 9b of the web 8a Keeps connection from the pressure chamber 22a to the pocket 62 closed.

Fig. 5

Next, the engine reaches idle speed. The control valve 48 remains currentless in its basic position. The hydraulic connection of the pressure chamber 24a to the annular chamber 100 is still open, while the web 8a or the right one Control edge 9b further separates the pressure chamber 22a and the pocket 62. The engine oil pressure increases and exceeds the minimum unlocking pressure at which the locking pin 53 via the oil pressure present in the annular chamber 100 his ring shoulder 55 against the spring force of the compression spring 57 in the unlocked Position is transferred.

Fig. 6

As the next step, the engine reaches an adjustment speed at which the control valve 48 is energized; thus the oil pressure is supplied via the control line B, which via the Annular groove 34, the radial bores 32, the annular space 30 and the radial bores 28a to 28e the pressure chambers 22a to 22e are supplied with oil. Since the passage from Pressure chamber 24a via pocket 62 and radial bore 61 to annular chamber 100 is still open, but the pressure oil supply via control line A to Annular chamber 100 no longer takes place, the oil pressure present in the annular chamber 100 drops from. The locking pin 53 still remains in its unlocked position simultaneously via the control line B, the channel 65 oil and the blind hole 64 oil End face 66 of the locking pin 53 is supplied. The one from the pressure chamber 22a the pocket 62 and the hydraulic passage guiding the radial bore 61 are still locked. The inner part 4 of the adjusting unit 6 now moves by one step towards the adjustment position, i.e. the webs 8a to 8e of the inner part 4 rise from the Ridges 14a to 14e of the cellular wheel 12.

Since the radial bores 28b to 28e are still more complete in the end position Overlap with the webs 14a to 14d (see Fig. 2), the Pressurizing the rotor at the beginning of the adjustment only via the pressure chamber 22a, with the radial bore 28a, which is only partially covered by the web 14e Pressure oil is applied. This will result in a too fast, uncontrolled initial adjustment movement prevented.

Fig. 7

The inner part 4 moves another step in the direction of the adjustment position, whereby the web 8a reaches a position in which it with its left and right Control edge 9a and 9b the pocket 62 both from the pressure chamber 22a and from Pressure chamber 24a closes here, so that in this state neither oil to the annular chamber 100 still reaches the blind hole 64. Nevertheless, the locking pin 53 remains in its unlocked position as it is hydraulically clamped and therefore no oil is over the pressure spaces 22a and 24a can escape.

Fig. 8

The engine speed continues to increase due to the oil pressure supply to the pressure rooms 22a to 22e, the inner part 4 of the adjustment unit 6 is moved a further step in Moved in the direction of the adjustment position, with the pressure chamber 22a at the same time End face 66 of the locking pin 53 supplied pressure is maintained. The Web 8a assumes a position with respect to pocket 62, in which the right one Control edge 9b of the web 8a of the hydraulic passage to the annular chamber 100 the pressure chamber 22a is released, so that the unlocked position of the Locking pin 53 is maintained. By the left control edge 9a hydraulic passage from the pressure chamber 24a to the annular space 100 is kept closed.

Fig. 9

The motor has reached an adjustment speed at which the webs 8a to 8b are in contact 8e of the inner part 4 on the webs 14a to 14e of the cellular wheel 12 is the maximum Adjustment path is reached.

Fig. 10

The engine speed is reduced, the control valve 48 is no longer energized, whereby it returns to its basic position and the oil pressure supply is now restored via the control line A to the pressure chambers 24a to 24e. It is hydraulic passage from the pressure chamber 22a to the pocket 62 open, but not the Transition from the pocket 62 to the radial bore 61 arranged in the web 8a, so that the oil pressure in the annular chamber 100 is maintained and the locking pin 53 remains in the unlocked position.

Fig. 11

The engine speed and thus the adjustment speed continues to decrease, the inner part 4 of the Adjustment unit 6 moves to the pressure spaces 24a to 12 due to the oil supply 24e further towards the locking position. Now the hydraulic passage is opened from the pressure chamber 22a to the annular chamber 100, the oil pressure in the Annular chamber 100 is dismantled via pressure line B to tank 50. Since the web 8a a Has reached the position at which the locking pin 53 with the elongated hole 63 comes into overlap, the locking pin 53 goes into its locked position.

Fig. 12

The engine speed continues to decrease, the control valve 48 remains de-energized in its Basic position and the inner part 4 of the adjustment unit 6 moves further in the direction its original locked end position. The one leading to the ring chamber 100 Hydraulic channel (pocket 62, bore 61) is due to the position of the web 8a closed both from the pressure chamber 22a and from the pressure chamber 24a. Both the to the annular chamber 100 leading hydraulic channel and to the end face 66 of the Locking pin 53 leading channel 65 are hydraulically relieved. That leaves the Locking pin 53 in its locked position.

Fig. 13

The inner part 4 of the adjustment unit 6 and thus that with the locking pin 53 provided web 8a moves further in the direction of the end position, being over the left Control edge 9a of the hydraulic channel leading to the annular chamber 100 by opening the Connection between pressure chamber 24a and pocket 62 is released. So that in the Annulus 100 oil pressure built up, so that the locking pin 53 back into the unlocked position is transferred.

The fact that the radial bores immediately before reaching the end position 28b to 28e again in complete overlap with the webs 14a to 14d of the Cell wheel 12 are brought (see Fig. 2), end position damping of the rotor reached.

Fig. 14

The inner part 4 of the adjustment unit 6 has reached its end position, i.e. the webs 8a to 8e of the inner part 4 are again on the webs 14a to 14e of the cellular wheel 12. The hydraulic passage from the pressure chamber 24a to the annular chamber 100 is still open, while the hydraulic connection from the pressure chamber 22a to the annular chamber 100 closed is. If the engine oil pressure drops, e.g. when switching off the engine, below the Unlocking oil pressure from, due to the spring force of the compression spring 57 Locking pin 53 securely transferred back to its locked position. So that is ensures that when the engine restarts from a state assuming that the locking pin 53 is in its locked position located.

The adjustment or locking method described above also takes place its application especially in the following operating conditions:

Idle operation of the internal combustion engine

When the engine is idling, the engine oil pressure drops as the oil temperature rises higher leakage losses and a higher pressure drop in the system. So that's enough no longer present in the pressure chambers 24a, the basic torque of the Camshaft and the cam generated by the running or running up Counteracting alternating moments. When the engine is running at idle speed, how described above, via the control line A the pressure chamber 24a and thus the Annulus supplied 100 oil. Because the engine oil pressure is greater than the minimum unlocking pressure the locking pin 53 according to FIG. 5 in its unlocked Position transferred. Due to the effects described above, the inner part 4 of the Move adjustment unit 6 in the adjustment direction, although at this time the Pressure chambers 22a are not supplied with oil. The inner part 4 of the adjustment unit 6 can however, only move to a position shown in Fig. 8, which is approximately 1 to 1.5 ° Adjustment angle corresponds. Then namely the oil pressure supply via the pressure chamber 24a Annular chamber 100 closed, while the oil pressure in the annular chamber 100 is present is reduced via the pressure chamber 22a and the control line B: Because in this Position of the locking pin 53 still overlapping with the elongated hole 63 is located, the adjustment unit 6 is locked again and the inner part 4 moves again back to its end position. This ensures that despite the alternating torques the camshaft, the inner part 4 of the adjusting unit 6 does not move into an uncontrolled manner undesired adjustment position moved.

Switch off the internal combustion engine

If the engine is switched off, the inner part 4 becomes due to the expiring moment of the cams moved or pressed in the adjustment direction. The control valve 48 is in a de-energized state its basic position. The movement of the inner part 4 in the direction of adjustment Pressure chamber 24a additionally built up oil pressure; however, the pressure space 24a may be due to of the check valve 51 arranged in the pressure line P is not hydraulically relieved become. However, the inner part 4 or the web 8a again reaches its one in FIG. 8 position shown, the annular chamber is analogous to the idle operation described 100 hydraulically relieved and the locking pin 53 in the elongated hole 63 locked so that when the engine is restarted it is ensured that the Adjustment unit 6 is in its locked end position.

A second embodiment of the invention shown in Figures 15 to 25 differs only in its constructive execution, whereby for the same components, the reference numerals are retained. Opposite the first The embodiment is the opening whose passage to the pressure spaces 22a and 24a in Dependence on the adjustment position of the inner part 4 is controlled as one in the Disc 16 arranged, at the ends closed elongated hole 62 'formed. The Elongated hole 62 'is in turn with a hole radially arranged in the web 8a 61 'connected to the annular chamber 100. Analogous to the first The exemplary embodiment is the hydraulic flow from the pressure chamber 24a or 22a the elongated hole 62 'and the hole 61' to the annular chamber 100 depending on controlled the rotational position of the inner part 4. The side surfaces of the web 8a act here again as control edges 9a 'and 9b'. The shown in Figures 15 to 25 Locking and adjustment states correspond to those in FIGS. 4 to 14 shown states according to the first embodiment, with the Description for the first embodiment is expressly made.

The device according to the invention is also for the adjustment of an intake camshaft suitable, in addition, the opening 62 or 62 'at other points of the Stator of the adjustment unit 6 may be arranged.

Claims (10)

Device for the relative rotation angle adjustment of a camshaft of an internal combustion engine to a drive wheel, with an inner part (4) connected in a rotationally fixed manner to the camshaft, which has at least approximately radially extending webs (8a to 8a) or wings, and with a driven cellular wheel (12) that several Cells distributed over the circumference and delimited by webs (14a to 14e), which are divided into two pressure chambers by the webs or wings of the inner part that are guided in an angularly movable manner, with the hydraulic pressure or pressure relief via control lines between the camshafts via the webs or wings two end positions can be rotated relative to the cellular wheel (12), and with at least one locking device which is effective between the inner part (4) and cellular wheel (12) and has a movable locking element (53) that has at least one counter element in the other of the two components cellular wheel ( 12) or inner part (4) together acts, whereby the inner part (4) can be locked in at least one end position with respect to the cellular wheel (12), the locking element (53) being locked or unlocked via at least one oil channel (61, 61 ') leading to the locking element (53) , characterized in that between two pressure chambers (22a, 24a) in or on the cellular wheel (12) there is an opening (62, 62 ') connected to the oil channel (61, 61'), the passage of which to the two pressure chambers (22a, 24a) is controlled as a function of the adjustment position of the inner part (4). Device according to claim 1, characterized in that the opening (62, 62 ') is partially or completely covered depending on the adjustment position by a web (8a) of the inner part (4), a bore (52.) In the web (8a) ) is arranged for receiving a locking pin (53). Apparatus according to claim 1 or 2, characterized in that the opening (62) is arranged on an inside of the cellular wheel (12) and that an oil hole (61) is provided on the end face of the web (8a), which is dependent on the rotational position of the inner part (4) communicates with the opening (62). Device according to claim 3, characterized in that the bore (61) leads to an annular chamber (100) via which the locking pin (53) can be unlocked. Device according to claim 1 or 2, characterized in that the opening (62 ') is arranged in a cover (16) which closes one side of the cellular wheel (12) and that an oil hole (61') arranged in the foot region of the web (8a) ) is provided which communicates with the opening (62 ') depending on the rotational position of the inner part (4). Apparatus according to claim 5, characterized in that the bore (61 ') leads to an annular chamber (100) via which the locking pin (53) can be unlocked. Device according to one of claims 4 to 6, characterized in that the oil supply to the annular chamber (100) via the pressure chamber (24a) or the pressure chamber (22a). Device according to one of the preceding claims, characterized in that an elongated hole (63) is arranged in a disk (16) closing the cellular wheel (12), in which the locking pin (53) is accommodated in its locking position. Apparatus according to claim 8, characterized in that an oil channel (65) leads to the elongated hole (63), so that the locking pin (53) can be unlocked from its end face (66). Device according to claim 9, characterized in that the end face (66) of the locking pin (53) is acted upon by oil pressure via a control line B, the pressure chamber (22a) and the channel (65).

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