DE102010044637A1 - Oscillating motor cam shaft adjuster has housing with hollow piston displaceable axially within housing, where borehole leads to recess that is exclusively assigned in hollow piston - Google Patents

Abstract

The oscillating motor cam shaft adjuster has a rotor (8), where a central valve is introduced in a rotor hub (7) of the rotor. The central valve has a housing with a hollow piston displaceable axially within the housing, where a borehole leads to a recess that is exclusively assigned in the hollow piston.

Description

The invention relates according to the one-part claim 1, a central valve for a Schwenkmotornockenwellenversteller.

The not pre-published DE 10 2010 013 777.4 already relates to a Schwenkmotorversteller having a hydraulic valve with a sleeve on a housing. By means of this sleeve it is achieved that a tank drainage channel T can cross the one working port A.

Moreover, the non-prepublished DE 10 2010 032 133.8 a Schwenkmotorversteller having a hydraulic valve that is manufactured as a complex component in the metal injection molding. Due to the complex shaping, it is achieved that a tank drainage channel T can cross one working port A.

Moreover, from the DE 42 37 193 A1 a Schwenkmotornockenwellenversteller with a displaceable within a sleeve piston known. In the wall of the sleeve, a longitudinal bore is drilled, which carries the hydraulic fluid from the supply port P to the piston, with which the hydraulic fluid to the two working ports A, B can be distributed. Coaxially on the socket, a sleeve is placed.

Furthermore, from the DE 10 2005 041 393 A1 a central valve for a Schwenkmotornockenwellenversteller known which has a piston which is guided within a socket. Axially consecutive a radial supply port P is provided, which is followed by a first radial working port B and a second radial working port A. This second radial working port A is followed by a tank outlet T, which forms the single tank outlet T. The piston is not rotationally symmetrical and has two separate and guided past each other channels. To move the piston axially, is applied to this a push rod of an actuator.

Also the DE 10 2005 052 481 A1 shows a central valve for a Schwenkmotornockenwellenversteller. In this central valve also follow the two working ports A, B the supply port P, which in turn follows a single tank outflow T.

The object of the invention is to provide a Schwenkmotorversteller with a central valve, which allows it in a cost effective manner, the two working ports A, B provide axially between a supply port P and a tank outlet T.

This object is achieved with the features of claim 1.

According to the invention, a connection sequence P-A-B or P-B-A is made possible. The supply port P is located on the camshaft. On the other hand, the tank drain T emerges at the other end of the central valve. Since the tank drain T but can receive its inflow both from the first working port A and the second working port B, a transfer point between the two working ports A, B must be provided. From this transfer point, the hydraulic fluid must be routed past one of the two working ports. For this purpose, a bore assigned to the tank outlet T is provided, which is supplied with the hydraulic fluid from the transfer point and thus crosses the one working port A or B. To pass the hydraulic fluid past this working port A or B, the bores for the tank drain T are arranged circumferentially offset from the transverse bores of the first working port A. The number of holes depends on the necessary flow cross-section. If this is low, a single large bore in the housing may be sufficient. A single large bore means cost-effective machining. In particular, light metal - such as aluminum - can be machined cost-effectively. The diameter and number of holes also depends on the load limit of the housing.

A high load of the housing results, for example, when the housing is designed as a screw, so that the central valve braces the rotor against the camshaft. Such a so-called central screw can be used to save space in existing engine concepts. In addition to the execution of the housing as a screw housing other types of attachment are possible. If the central valve does not brace the rotor against the camshaft, then simple clamping connections or, for example, a bayonet closure are feasible.

If the housing is designed as a screw housing, then a tool attack - in particular a hexagon - and a thread is provided, which braces the rotor of the Schwenkmotornockenwellenverstellers against a camshaft part. This camshaft part may be the camshaft itself or a welded or pressed-in insert.

In a particularly advantageous manner, a sieve may be provided which prevents dirt from entering the central valve. This compound can be carried out particularly convenient mounting as a snap or clip connection.

In a particularly advantageous embodiment, it is possible to use pressure fluctuations in the first working port B associated pressure chambers of the Schwenkmotornockenwellenverstellers to supply the opposite direction of rotation associated pressure chambers with sufficient fluidic volume flow. These pressure variations result from the camshaft alternating torques that occur at the camshaft in response to the gas exchange valve forces. The smaller the number of combustion chambers per camshaft, the stronger the camshaft alternating torques, so that the use of the camshaft alternating torques offers particular advantage in internal combustion engines with three cylinders. Furthermore, influencing parameters are still the strength of the gas exchange valve springs and the camshaft speed.

Further advantages of the invention will become apparent from the other claims, the description and the drawings.

The invention is explained in more detail with reference to an embodiment.

Show

1 a swivel camshaft adjuster in a cutaway view,

2 in a perspective view of a central valve, which in a Schwenkmotornockenwellenversteller according to 1 is used,

3 the central valve off 2 in a sectional view along a central axis, wherein a displaceable hollow piston is unloaded by an electromagnetic actuator,

4 a representation analog 3 wherein the hollow piston is displaced from the electromagnetic actuator to its center position,

5 a representation analog 3 wherein the hollow piston is displaced from the electromagnetic actuator to its end position,

6 the central valve in a section transverse to its central axis, wherein the section passes through a first working port A,

7 the hollow piston as a single part and

8th a schematic representation of the central valve.

With a Schwenkmotornockenwellenversteller according to 1 is changed during operation of an internal combustion engine, the angular position between the crankshaft and the camshaft. By turning the camshaft, the opening and closing times of the gas exchange valves are shifted so that the internal combustion engine brings its optimal performance at the respective speed. The Schwenkmotornockenwellenversteller allows infinite adjustment of the camshaft relative to the crankshaft. The Schwenkmotornockenwellenversteller has a cylindrical stator 1 on, the rotation with a drive wheel 2 connected is. In the embodiment, the drive wheel 2 a sprocket over which a chain, not shown, is guided. The drive wheel 2 but may also be a toothed belt, over which a drive belt is guided as a drive element. About this drive element and the drive wheel 2 is the stator 1 Driven with the crankshaft.

The stator 1 comprises a cylindrical stator base body 3 , on the inner side radially inwardly at equal intervals webs 4 protrude. Between neighboring bridges 4 become spaces 5 formed, into, over, a in 2 closer illustrated valve 12 controlled, pressure medium is introduced. Between neighboring bridges 4 protrude wings 6 radially outward from a cylindrical rotor hub 7 a rotor 8th protrude. These wings 6 divide the spaces between 5 between the bridges 4 each in two pressure chambers 9 and 10 ,

The bridges 4 lie with their end faces sealingly on the outer circumferential surface of the rotor hub 7 at. The wings 6 in turn lie with their end faces sealingly on the cylindrical inner wall of the stator main body 3 at.

The rotor 8th is rotatably connected to the camshaft, not shown. To change the angular position between the camshaft and the crankshaft, the rotor becomes 8th relative to the stator 1 turned. For this purpose, depending on the desired direction of rotation, the pressure medium in the pressure chambers 9 or 10 pressurized while each other's pressure chambers 10 or 9 be relieved to the tank drain T out. To the rotor 8th opposite the stator 1 to pivot counterclockwise in the position shown are from the valve 12 radial bores 11 in the rotor hub 7 put under pressure. To the rotor 8th on the other hand, to turn clockwise will be from the valve 12 radial bores 18 in the rotor hub 7 pressurized, leaving the pressure chambers 9 be filled.

The valve 12 is in 2 seen in a perspective view as a single part. The valve 12 is designed as a central valve. In this case, a main body of this central valve forms a housing 22 , The housing 22 has at a rear end executed as a hexagon tool attack 51 and at a front end one threaded pin 24 on. This definition of "back" and "front" will also be used in the following.

The valve 12 is in the mounted state in the rotor hub 7 plugged in and / or screwed. In the 1 dashed radial holes 18 the rotor hub 7 lead thereby over an annular groove 15 in the rotor hub 7 of the valve 12 to cross holes 19 in the case 22 that form a first working port A.

Adjacent to this first working connection A is a second working connection B and a special working connection B '. This particular working port B 'is basically assigned to the second working port B and serves the use of camshaft alternating torques for quick or oil-saving adjustment. The housing 22 is graded several times by means of paragraphs. The first working port A is on the large diameter 20 arranged, which is the medium-sized diameter 21 follows, on which the two working ports B and B 'are arranged. It follows a small diameter 23 on which an oil supply port P is arranged. This small diameter 23 finally follows the threaded pin 24 , which is screwed into the camshaft and thus the rotor 8th braced against the camshaft.

The second working port B are transverse bores 25 assigned. The Ölversorgunsgsanschluss P are transverse bores 26 assigned. The hydraulic pressure from the oil pump to the supply port P may be supplied from the camshaft or a camshaft bearing.

From the oil supply port P, the hydraulic fluid passes through the cross bores 26 in a central receiving hole 27 inside the case 22 directed. In this mounting hole 27 is a hollow piston closed on both sides 28 received axially displaceable.

To the hollow piston 28 to move is a rear end of the hollow piston 28 with a sealing plug 29 on an actuating tappet 30 an electromagnetic actuator. It loads a helical compression spring 31 the hollow piston 28 in the on the actuating tappet 30 pointing direction. Between the actuating tappet 30 and the hollow piston 28 is in the de-energized state an axial clearance available, which serves to compensate for tolerances. However, with the ignition switched on, the actuator is energized slightly until the actuating tappet 30 on the hollow piston 28 is applied. The helical compression spring 31 is at the front end of the hollow piston 28 in a blind hole 32 used and is based on the blind hole bottom 33 from. This is the rear end of the helical compression spring 31 also guided radially. At the front end is the helical compression spring 31 while on a paragraph 34 supported, the one concentric to a central axis 13 and thus the receiving bore 27 aligned compensation hole 35 follows and leads into the camshaft. The Hohlkoben 28 is by means of a in the receiving bore 27 axialfest used axial securing ring 36 secured against loss during assembly and positioned axially in its rest position. In this in 3 shown rest position, the hydraulic fluid from the oil supply port P via an annular groove 39 on the hollow piston 28 on the cross hole 25 performed at the second working port B and in return from the first working port A to the tank outlet T out. On both sides of this ring groove 39 forming ring bridges 40 . 41 prevent the hydraulic flow to the tank drain T and to the compensation hole 35 , At this tank drain T, the hydraulic fluid flows from the transverse bore 19 over milled depressions 42 to a ring channel 43 , the inside of the housing 22 turned off. From this ring channel 43 go several axially extending holes 44 from. The milled depressions 42 allow targeted throttling to the tank drain T.

These also in 6 in cross-section apparent holes 44 are circumferentially between the cross holes 19 arranged the first working port A. These holes 44 lead to tank drain T.

The wells 42 are circumferentially distributed on the rear ring land 40 arranged. The depressions form 42 with the ring channel 43 a transfer point 53 , which can alternately from the two working ports A or B, the hydraulic fluid to the tank outlet T can pass.

It is in one of the transverse bore 26 following turn 37 a check valve 38 used that the hydraulic pressure within the housing 22 locked, so that pressure variances are not passed to the oil pump due to the rotational irregularities on the camshaft. Instead, these are available for the camshaft adjustment. This relationship is closer in the DE 10 2006 012 775 A1 explained.

By displacement of the hollow piston 28 in the in 5 illustrated end position of the hollow piston 28 is the hydraulic fluid from the oil supply port P via a channel 52 feasible on the first working port A and in turn from the second working port B to the tank drain T feasible. The hydraulic fluid flows from the supply port P via front transverse bores 45 in the hollow piston 28 into it. The hydraulic fluid flows inside the hollow piston 28 to the rear transverse bores 46 , From these rear cross holes 46 the hydraulic fluid enters an annular channel 47 outside on the hollow piston 28 , From this ring channel 47 that flows Hydraulic fluid in an inside of the housing 22 turned ring channel 48 , In this ring channel 48 finally lead to the cross holes 19 of the first working connection A.

The special working port B 'for the use of the camshaft alternating torques has transverse bores 49 on the housing 22 on the inside of a band-shaped check valve 50 are closed. This check valve locks 50 analogous to the other check valve 38 internal pressures, whereas external pressures are allowed to pass through. So exceeds the pressure in the pressure chambers 10 the pressure in the recess 27 in the case 22 , so the pressure is let into the recess and can through the front cross holes 45 in the hollow piston 28 be introduced. Thus, this hydraulic fluid is finally the pressure chambers 9 provided for adjustment.

From the cross holes 25 the second working port B, the hydraulic fluid through the wells 42 in the ring channel 43 passed, which the hydraulic fluid through the holes 44 leads to the tank drain T.

4 shows the hollow piston 28 in a middle position. In this middle position, the pressure in the two working chambers according to DE 198 23 619 A1 locked up.

• – für die Einlassventile oder
• – für die Auslassventile

aufgesetzt ist. Außerdem wird die bevorzugte Drehrichtung des Schwenkmotornockenwellenverstellers durch die Vorspannung einer nicht näher dargestellten Spiralfeder bestimmt, welche den Rotor gegenüber dem Stator vorspannt und das Reibmoment der Nockenwelle gegenüber dem Gaswechselventiltrieb kompensiert. Dabei kann die Spiralfeder so stark ausgelegt sein, dass sie das Reibmoment überkompensiert oder auch so schwach ausgelegt sein, dass sie das Reibmoment nicht gänzlich kompensieren kann. Eine solche Spiralfeder ist beispielsweise in der nicht vorveröffentlichten DE 10 2009 048 238.5 dargestellt.The pressure chambers at the first working port B assigned to the use of camshaft alternating torques can be assigned to the adjustment after early or the adjustment after late. Depending on whether the Schwenkmotornockenwellenversteller on the camshaft

• - for the intake valves or
• - for the exhaust valves

is attached. In addition, the preferred direction of rotation of the Schwenkmotornockenwellenverstellers is determined by the bias of a coil spring, not shown, which biases the rotor relative to the stator and compensates the friction torque of the camshaft relative to the gas exchange valve drive. In this case, the coil spring can be designed so strong that they overcompensated the friction torque or be designed so weak that they can not fully compensate for the friction torque. Such a coil spring is for example in the not pre-published DE 10 2009 048 238.5 shown.

In both embodiments, an external thread on the threaded pin 24 intended. This external thread allows the rotor 8th or, the rotor hub 7 To clamp against a built camshaft or a camshaft adapter of the camshaft. Then there is the one end of the rotor hub 7 directly or for example via a counter-holder on the executed as a screw head tool attack 51 at. The other end of the rotor hub 7 is then directly or for example via a friction disc on the camshaft. Such a friction disc and such an anvil are for example in the DE 10 2009 050 779.5 described. In this case, the friction disc is provided to increase the transmittable torque between the end face of the camshaft and the rotor. It is also possible to orient the angle of the rotor against the camshaft by a dowel pin aligning the camshaft and the rotor against each other.

8th shows a schematic representation of the central valve. It can be seen that it is a 4/3-way proportional valve.

It is also possible to assign the use of camshaft alternating torques to both directions of rotation by allocating additional transverse bores for the use of camshaft alternating torques to both working ports A, B.

The holes 44 in the case 22 do not have to be parallel to the central axis 13 be aligned.

In the area of the supply connection P, a sieve can still be provided which retains large dirt particles.

Instead of the screw head is also another tool attack 51 possible. For example, a square or a round head can be used. It is also possible to provide there on the housing a second thread on which a nut is screwed. This nut can also have a hexagonal, a square, a polygonal or another profile. In this case, then the tool engagement and the thread is placed on a common end of the housing.

In a further embodiment, an internal thread is conceivable instead of the external thread. Then the housing is screwed onto a threadedly connected to the cam shaft threaded rod.

The camshaft can be designed in particular as a built-up camshaft. In such a built camshaft, this is in particular designed as a hollow tube, on which the cams are immovably plugged or pressed with a micro-toothing.

Cross holes according to this description do not have to be exactly at right angles to the central axis 13 run. It is also possible to let them slant. It is also possible the bore or holes 44 to run obliquely. In particular, the hole 44 from the tank connection T to the hollow piston run obliquely inwards. In this case, if necessary. On the annular channel 43 be waived. However, in order not to block the hollow piston positioned at an angle, would then have to hollow piston instead of the wells 42 be provided a circumferential annular groove.

The described embodiments are only exemplary embodiments. A combination of the described features for different embodiments is also possible. Further, in particular not described features of the device parts belonging to the invention are to be taken from the geometries of the device parts shown in the drawings.

LIST OF REFERENCE NUMBERS

1

stator

2

drive wheel

3

stator base

4

Stege

5

interspaces

6

wing

7

rotor hub

8th

rotor

9

pressure chamber

10

pressure chamber

11

radial bores

12

central valve

13

central axis

14

transverse channels

15

ring groove

16

ring groove

17

shell

18

drilling

19

drilling

20

big diameter

21

medium-sized diameter

22

casing

23

small diameter

24

threaded pin

25

cross holes

26

cross holes

27

location hole

28

hollow piston

29

sealing plug

30

actuating ram

31

Helical compression spring

32

blind

33

Blind basis

34

paragraph

35

compensating bore

36

axial securing

37

recess

38

check valve

39

ring groove

40

ring land

41

ring land

42

wells

43

annular channel

44

drilling

45

cross holes

46

cross holes

47

annular channel

48

annular channel

49

cross holes

50

check valve

51

tool application

52

channel

53

Transfer point

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010013777 [0002]
• DE 102010032133 [0003]
• DE 4237193 A1 [0004]
• DE 102005041393 A1 [0005]
• DE 102005052481 A1 [0006]
• DE 102006012775 A1 [0037]
• DE 19823619 A1 [0041]
• DE 102009048238 [0042]
• DE 102009050779 [0043]

Claims (11)

Schwenkmotornockenwellenversteller with a rotor ( 8th ), in whose rotor hub ( 7 ) a central valve ( 12 ), which is a housing ( 22 ) with an axially displaceable within this hollow piston ( 28 ), wherein two working ports (A, B) are axially adjacent to each other, and axially adjacent to these on the camshaft side facing a supply port (P) and a tank drain (T) on the side facing away from the camshaft side of the housing ( 22 ) is led out, whereby from the tank drain (T) to a recess exclusively assigned to this ( 42 ) in the hollow piston ( 28 ) a hole ( 44 ) in the housing ( 22 ) which extends circumferentially offset to the first working port (A). Schwenkmotornockenwellenversteller according to claim 1, characterized in that the recess ( 42 ) a transfer point ( 53 ), which lies axially between the two working ports (A, B). Schwenkmotornockenwellenversteller according to claim 1 or 2, characterized in that the hollow piston ( 28 ) on whose side facing the camshaft via a compensating bore ( 35 ) is relieved. Schwenkmotornockenwellenversteller according to claim 1, characterized in that the hollow piston ( 28 ) by means of a helical compression spring ( 31 ) against an actuating tappet ( 30 ) is pressed. Schwenkmotornockenwellenversteller according to claim 4, characterized in that the hollow piston ( 28 ) is axially closed at both ends, wherein at the ends of the intermediate region openings (transverse holes 45 . 46 ) in the hollow piston ( 28 ) are provided by the in a disengaged position of the actuating tappet ( 30 ) a channel ( 52 ) from the supply port (P) to the first working port (A). Schwenkmotornockenwellenversteller according to any one of the preceding claims, characterized in that the bore ( 44 ) radially within a tool attack ( 51 ) exit. Schwenkmotornockenwellenversteller according to any one of the preceding claims, characterized in that a plurality of bores circumferentially offset to a plurality of transverse bores ( 19 ) of the first working port (A) to the tank outlet (T) are guided. Schwenkmotornockenwellenversteller according to any one of the preceding claims, characterized in that the housing ( 22 ) at its axial end a threaded pin ( 24 ) having the rotor hub ( 7 ) axially braced against the camshaft. Schwenkmotornockenwellenversteller according to one of the preceding claims, characterized in that axially between the supply port (P) and the second working port (B) a working connection (B) associated working port (B ') is arranged for the particular use of camshaft alternating torques. Schwenkmotornockenwellenversteller according to any one of the preceding claims, characterized in that the housing ( 22 ) a threaded pin ( 24 ) having. Schwenkmotornockenwellenversteller according to any one of the preceding claims, characterized in that only on the camshaft side facing a tank outlet (T) is provided.

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