DE202014004439U1 - Arrangement for driving an adjusting shaft for adjusting the expansion stroke and / or the compression ratio of an internal combustion engine - Google Patents

Abstract

Arrangement for driving an adjusting shaft for adjusting the expansion stroke and / or the compression ratio of an internal combustion engine, wherein the arrangement comprises a drive motor and a drive connected downstream of the drive motor, characterized in that a. On the gearbox output side on the one hand radially flexible and / or transversely to the axial direction bendable and on the other hand torsionally stiff coupling is connected to the transmission, or that b. the transmission is arranged and adapted to be connected via an on the one hand radially flexible and / or axially bendable and torsionally rigid coupling to an adjusting for adjusting the expansion stroke and / or the compression ratio of an internal combustion engine.

Description

The invention relates to an arrangement for driving an adjusting shaft for adjusting the expansion stroke and / or the compression ratio of an internal combustion engine, wherein the arrangement comprises a drive motor and a gear downstream of the drive motor.

Out DE 10 2011 116 952 A1 is a multi-joint crank drive of an internal combustion engine, with a plurality of rotatably mounted on crank pins of a crankshaft coupling links and a plurality of rotatably mounted on crank pins of an adjusting Anlenkpleueln, each of the coupling links pivotally connected to a Kolbenpleuel a piston of the internal combustion engine and one of the Anlenkpleuel and the angular position of Adjusting shaft by means of an adjusting device within a certain range of rotation angle is adjustable, known. It is provided that the adjusting shaft by means of a locking device in at least one rotational angle locking position can be fixed. Specifically, it is proposed that the adjusting device has a gear with a drive wheel rotatably mounted on the adjusting shaft. In particular, the transmission is a worm gear, wherein the output gear is formed as a worm wheel. This device is disadvantageously not very durable and not very precise over time.

Out EP 2 022 959 A2 a device for variably adjusting the compression is known, which has a multi-joint crank drive and in which an adjusting device for adjusting the rotational angle of an adjusting shaft comprises a lever arrangement. About the lever assembly, the adjustment can be rotated and thus set a desired angular position. Also, this device is disadvantageously not very durable and does not allow permanent precise adjustment.

It is therefore an object of the present invention to provide an arrangement which allows a long-lasting precise and reliable adjustment of a desired rotational position of an adjusting shaft, in particular an eccentric shaft, for adjusting the expansion stroke and / or the compression ratio of an internal combustion engine.

• a. getriebeabtriebsseitig eine einerseits radialflexible und/oder quer zur Axialrichtung biegbare und andererseits torsionssteife Kupplung an das Getriebe angeschlossen ist, oder dass
• b. das Getriebe dazu angeordnet und ausgebildet ist, über eine einerseits radialflexible und/oder axial biegbare und andererseits torsionssteife Kupplung an eine Verstellwelle zum Verstellen des Expansionshubes und/oder des Verdichtungsverhältnisses eines Verbrennungsmotors angeschlossen zu werden.

The object is achieved by an arrangement which is characterized in that

• a. On the transmission output side, on the one hand, a radially flexible and / or transversely to the axial direction bendable and torsionally stiff coupling is connected to the transmission, or that
• b. the transmission is arranged and adapted to be connected via an on the one hand radially flexible and / or axially bendable and torsionally rigid coupling to an adjusting for adjusting the expansion stroke and / or the compression ratio of an internal combustion engine.

In accordance with the invention, it was first recognized that an arrangement for adjusting the rotational position of an adjusting shaft, as known from the prior art, not only has to apply the torque for adjusting the adjusting shaft, but also forces and torques of the adjusting shaft on the arrangement acting, which burden the arrangement. These forces result from the fact that the internal combustion engine via the coupling mechanism, via which it is coupled with the adjusting shaft, constantly and repeatedly transmits forces and torques on the adjusting shaft. By these forces in particular a bending of the adjusting is effected. In the area in which the arrangement is coupled for adjusting the adjusting shaft, in particular forced, radial vibrations of the adjusting shaft, which sustainably load the drive motor and / or the gearbox, occur.

It has been recognized that these are particularly detrimental to the mentioned forces and torque loads, the greater the game of the transmission, via which the drive motor is coupled to the adjusting shaft. In particular, the effects are particularly disadvantageous for the life of the arrangement for adjusting the adjusting shaft. An existing game is namely increased by the described, permanent and high-frequency load after a relatively short time so that a precise setting a desired rotational position is no longer possible reliably.

To avoid the loads that are transmitted by the adjusting shaft, according to the invention, on the output side, a radially flexible and / or transversely to the axial direction bendable and, on the other hand, torsionally rigid coupling is provided. By this measure, the transmission is effectively decoupled from the radial movements that performs the adjusting shaft, without the transferability of a torque is adversely affected by the transmission to the adjusting shaft.

In particular, it may be advantageously provided that the transmission is arranged and designed to be connected via such, for example, already mounted on an internal combustion engine, coupling. This can be advantageous in particular in plug-in construction, in which an output shaft of the transmission is inserted into a corresponding receptacle of the coupling, be realized. It is alternatively also possible that the coupling is part of the arrangement for adjusting and the entire Arrangement, for example in plug-in construction, is coupled to the internal combustion engine and fixed.

The coupling can advantageously be designed, for example, as a dog clutch or as a multi-disc clutch or as a flexible shaft coupling or as Oldham clutch or as bellows clutch. Particularly advantageous is the use of a multi-plate clutch, because this design requires only a few components. In particular, in a multi-plate clutch, unlike, for example, in an Oldham clutch, no moving components must be slidably mounted relative to each other.

As an alternative or in addition to a coupling, the problems which are caused by the forces and / or torques transmitted via the adjusting shaft can also be substantially reduced or even completely eliminated by designing the gearbox as a backlash-free gearbox. It has been shown that a backlash-free transmission is much less sensitive to the forces and torque transmitted by the adjusting shaft, in particular an eccentric shaft. In arrangements with play, the forces and torques accumulate on the way to the respective end position of the game, so that they particularly burden the transmission when hitting the end positions and damage over time. In the inventive manner was further recognized that this phenomenon can not occur in backlash-free gearboxes.

It has been shown that a particularly reliable and long-lasting adjustment of the rotational position of an adjusting shaft for adjusting the expansion stroke and / or the compression ratio of an internal combustion engine is made possible in an arrangement in which the transmission is designed as a stress wave transmission.

Such a stress wave transmission can be designed for example as a pot gear. In such a transmission, the elastic Flexspline is formed in top shape (Flextopf).

In a special, other embodiment, the stress wave transmission is designed as a ring gear. In such an embodiment, the elastic Flexspline is not in the form of a pot, but in a ring shape (flex ring). Such a construction is advantageously particularly axially particularly compact, which facilitates the connection to an internal combustion engine substantially. In addition, such an embodiment of the stress wave transmission is particularly insensitive to radial vibrations of a coupled adjusting shaft. This is in contrast to a design in top form, because a Flextopf, which is sensitive to radical stresses due to its flexibility, is not present. However, even with such a construction, as well as when using a voltage wave transmission in pot construction or when using another type of backlash-free transmission, further measures, as described below, for the compensation and / or avoidance of loads transmitted from the adjusting shaft be provided.

As another type of usable, backlash-free transmission, for example, a backlash-free planetary gear can be used. However, such planetary gear are very complex and therefore very expensive and prone in practice as voltage wave transmission.

Alternatively, or in addition to a radial decoupling is in a particularly advantageous embodiment, the transmission as a tension shaft gear, in particular in the form of a ring gear, formed with a connected to the transmission output dynamic spline or connected to the transmission output circular spline, in particular exclusively, sliding is.

Such a design is particularly robust and solid. In particular, such a design can be designed such that via the transmission output coupled, radial movements of the adjusting shaft on the slide bearing and other components of the assembly, such as an actuator, on a housing, in particular a crankcase, the internal combustion engine and / or in a vehicle body are derived , A slide bearing also has the very special advantage that it can be made very robust and beyond that is inexpensive to produce. Such an embodiment also has the advantage that it is particularly durable and the initially described effects of cumulative forces and / or torques, which ultimately lead to premature wear, can be effectively avoided. In particular, such an embodiment can also manage without additional measures for compensation and / or for avoiding loads which are transmitted by the adjusting shaft.

As already mentioned, it can be advantageously provided that the drive motor and the transmission are arranged in a common housing. The housing may also include additional components, such as a clutch for coupling to an internal combustion engine. In particular, it may be advantageously provided that the arrangement for driving an adjusting shaft is designed as an actuator module, which can be coupled as a prefabricated system part to an internal combustion engine.

Particularly advantageous is an internal combustion engine having an adjusting shaft for adjusting the expansion stroke and / or the compression ratio, to which an arrangement according to the invention for adjusting the adjusting shaft is connected. Such an internal combustion engine is characterized in particular by the fact that the expansion stroke and / or the compression ratio can also be set accurately and reliably over longer periods of use.

To compensate for and / or to avoid loads that are transmitted from the adjusting, is provided - according to an independent inventive idea - in a particular embodiment that the arrangement or at least a portion of the arrangement is supported by a holding device so movable that the arrangement or at least part of the arrangement can follow a radial movement and / or a bending movement of the adjusting shaft.

Such a design has the very particular advantage that the forces and / or torques transmitted via the adjusting shaft to the arrangement essentially do not stress the components in the arrangement itself, but essentially only move the arrangement as a whole. In this way it is possible to dispense with additional measures for decoupling and / or compensation of the transmitted via the adjusting shaft forces and / or torques. However, it is also possible to support the arrangement in the manner mentioned movable and also to provide additional measures, as described above.

Advantageously, in a movable mounting of the entire arrangement or at least a part of the arrangement, a torque support may be present, by means of a torque acting on the adjusting shaft in the application of a torque counter-torque in a housing of the internal combustion engine and / or - directly or indirectly - can be derived in a vehicle body, wherein the torque support is arranged and designed such that the arrangement or at least a part of the arrangement of a radial movement and / or a bending movement of the adjusting shaft can follow. Alternatively or additionally, it is also possible for the holding device to function as a torque support, by means of which a counter-torque acting on the arrangement when applying a torque to the arrangement can be diverted into a housing of the internal combustion engine and / or directly or indirectly into a vehicle body.

A particularly advantageous embodiment includes a locking device for blocking a rotational movement of a rotary component of the drive motor or the transmission. Such a design has the particular advantage that the arrangement for driving an adjusting shaft for adjusting the expansion stroke and / or the compression ratio - and thus indirectly also the adjusting shaft itself - for example, in case of failure in a predefined position, in particular an emergency position, can be maintained. In this way, it is advantageously prevented that the system is left uncontrolled in the event of a fault and settings are reached that are unfavorable for an emergency operation or even lead to damage of the arrangement for driving and / or the internal combustion engine.

It can also be advantageously avoided by means of a locking device that when the system is switched off - the crankshaft is unintentionally rotated relative to the adjusting shaft, for example when the vehicle is switched off, which would result in the actual rotational angle of the adjusting shaft not coinciding with the original rotational angle after switching on again that a controller has saved last.

In particular, the locking device may comprise a movable locking bolt which is movable for blocking a rotational movement of the rotary member from a release position into a blocking position in which the locking bolt engages in a locking receptacle of the rotary member.

For example, can be advantageously provided that a movable locking bolt is pressed by means of a spring device in the blocking position and that an adjustment, such as an electromagnet is present to pull the locking bar against the force of the spring device in the release position. However, this embodiment has the disadvantage that the locking bolt is automatically transferred in a fault, for example in a power failure, in the blocking position and the blocking can be solved only consuming again.

In a particularly advantageous embodiment, it is provided that the locking bolt with an adjusting from the release position against the force of a return element in the blocking position is movable and that the locking bolt by means of the rotary member, for example by frictional engagement and / or positive engagement, in the blocking position can be fixed , Such a system solves the conflict of objectives that on the one hand in the presence of an error, such as in particular in the case of a power failure, a, in particular automatic, blocking can take place and that despite the error blocking can be solved again.

The fact that the locking bolt can be held by means of the rotary member against the force of the return element in the blocking position, is de facto - created a bistable system - even in the error situation. On the one hand, the blocking position can be maintained by means of the rotary member itself; On the other hand, the rotary member can release the locking bolt, so that the return element, which may be formed, for example, as tensioned in the blocking position spring, can move it into the release position.

The drive motor may advantageously be designed, for example, as a brushless motor and / or as a DC motor. In a particular embodiment, which may be formed in particular very compact, the drive motor is designed as a hollow shaft motor. In particular, the drive motor may advantageously be designed as an electronically commutated three-phase motor.

In a particularly advantageous embodiment, the arrangement for driving an adjusting shaft for adjusting the expansion stroke and / or the compression ratio on a rotary position sensor to measure the angular position of at least one rotational component of the drive motor and / or the transmission and / or the adjusting directly or indirectly.

In a particularly advantageous manner, the arrangement for driving an adjusting shaft for adjusting the expansion stroke and / or the compression ratio may include a control and sensor module. In particular, it may be advantageously provided that different control and sensor modules are available for use in different internal combustion engines, so that an arrangement according to the invention for driving an adjusting shaft can be easily adapted to changed requirements by replacing the control and sensor module. In an advantageous manner, it can be provided in particular that the control electronics of such a control and sensor module both the functional electronics, in principle - for example, for controlling and / or regulating the commutation - is necessary to operate a drive motor of an actuator, as well as actual command electronics, which controls or regulates the desired parameters, such as direction of rotation and / or rotational speed and / or torque and / or rotational position, etc. includes. In an advantageous manner, it can also be provided in particular that the rotary position sensor already mentioned above is part of the control and sensor module.

In a particularly advantageous embodiment of the internal combustion engine, an adjustment of the expansion stroke and / or the compression ratio is possible only at a predetermined or predefinable phase angle of the crankshaft of the internal combustion engine. In particular, it can be provided that the arrangement, in particular the drive motor of the arrangement, can be activated only in the case of a predetermined or predefinable phase position of the crankshaft of the internal combustion engine. In this way it can be achieved that an adjustment is made exclusively in this favorable periods of the power stroke of the internal combustion engine.

Alternatively or additionally, it may also be provided that the transmission, in particular in the form of a stress wave transmission, is designed as a non-reversible transmission. In this way it is ensured that a setting made is maintained even if the drive motor is temporarily switched off, for example to save energy.

The coupling of the adjusting shaft to a crankshaft of the internal combustion engine can be realized for example via a multi-joint crank drive.

In the drawing, the subject invention is shown schematically and will be described with reference to the figures below, wherein the same or equivalent elements are usually provided with the same reference numerals. Showing:

1 and 2 an overview representation for illustrating the phenomenon of the transmission of forces and torques via an adjusting shaft to an arrangement for adjusting the rotational position of the adjusting shaft,

3 An embodiment of an inventive arrangement for adjusting the rotational position of an adjusting shaft,

4 A second embodiment of an inventive arrangement for adjusting the rotational position of an adjusting, and

5 a part of an embodiment of an internal combustion engine according to the invention with an inventive arrangement for adjusting the rotational position of an adjusting.

1 shows schematically in cross section an internal combustion engine 1 with a multi-joint crank drive with which the expansion stroke and the compression ratio is adjustable. To adjust an adjusting shaft 2 , which may be formed as an eccentric shaft, rotated and the adjustment movement via a Verstellpleuel 3 and a hinged with the Verstellpleuel 3 connected lever 4 transfer. The piston shown in this figure 5 of internal combustion engine 1 is over a connecting rod 6 articulated coupled to the lever. The adjusting lever 4 is in turn via a lift arm 7 to a crankshaft 8th coupled.

On the connecting rod 4 act oscillating and changing sign of mass and gas forces F of the piston 5 that over the adjusting lever 4 and the Verstellpleuel 3 on the adjusting shaft 2 be transmitted.

The 2a and 2 B show schematically this situation in a longitudinal cross-sectional view. The adjusting shaft 2 is, for example, in the crankcase, stored multiple times and is charged at different points by the forces described F constantly and repetitive. Due to the forces described, the adjusting bends and tilts in the camps, resulting in 2 B is illustrated. In the in 2 B illustrated end region 9 in which an arrangement for adjusting the adjusting shaft 2 is to be coupled, occur in particular forced, radial vibrations of the adjusting 2 on, which can permanently burden the drive motor and or the transmission of an arrangement for adjusting.

3 shows an embodiment of an inventive arrangement 10 for adjusting the rotational position of an adjusting shaft 2 , in particular an eccentric shaft. The order 10 has a drive motor 11 and a drive motor 11 downstream backlash-free gearbox 12 on, as a stress wave transmission 13 is formed in the form of a ring gear.

The stress wave transmission 13 has one of the drive motor 11 driven, in cross-section elliptical wave generator 14 on. The wave generator 14 is by means of a rolling bearing 15 rotatable in an annular flexspline 16 stored and deformed this. The Flexspline 16 engages with its external teeth both in the internal teeth of a fixed to a transmission housing 22 connected Dynamicsplline 17 , as well as in the internal toothing of a Circularspline 18 one.

The Circularspline 18 forms the transmission output and is non-rotatably via a flexible one hand and / or transversely to the axial direction bendable and torsionally stiff on the other hand coupling 19 , for example, as a steel disk clutch 20 may be formed on the adjusting shaft 2 coupled.

The Circularspline 18 is about a first sliding bearing 21 radially relative to the transmission housing 22 rotatably mounted. In addition, one is rotatable with the Circularspline 18 connected coupling plate 23 for connecting the Circularspline 18 with the clutch 19 - and thus indirectly also the Circularspline 18 itself - axially by means of a second sliding bearing 24 rotatably mounted.

The gearbox 22 is directly on the crankcase 25 attached to an internal combustion engine.

4 shows a second embodiment of an inventive arrangement 10 for adjusting the rotational position of an adjusting shaft 2 , In this embodiment, the drive motor 11 , unlike the one in 3 illustrated embodiment, axially parallel to the transmission 12 and the adjusting shaft 2 coupled. In this embodiment, the transmission of torque from the drive motor takes place 11 on the wave generator 14 the stress wave transmission 13 via a traction mechanism drive, namely a belt drive 26 , As traction drive would, for example, a chain drive in question. The belt drive 26 has one to the drive motor 11 coupled first pulley 27 and one to the wave generator 14 coupled second pulley 28 , as well as a belt 29 on. In this embodiment, the wave generator 14 by means of other rolling bearings 30 relative to the transmission housing 22 rotatably mounted.

Also in the second embodiment forms the Circularspline 18 the transmission output, the rotationally fixed on a hand radially flexible and / or transversely to the axial direction bendable and torsionally stiff coupling on the other hand 19 , for example, as a steel disk clutch 20 may be formed on the adjusting shaft 2 is coupled.

Also in the second embodiment is the Circularspline 18 via a first sliding bearing 21 radially relative to the transmission housing 22 rotatably mounted. In addition, one is rotatable with the Circularspline 18 connected coupling plate 23 for connecting the Circularspline 18 with the clutch 19 - and thus indirectly also the Circularspline 18 itself - axially by means of a second sliding bearing 24 rotatably mounted.

5 schematically shows a part of an embodiment of a part of an internal combustion engine according to the invention 1 with an inventive arrangement 10 for adjusting the rotational position of an adjusting shaft 2 ,

The order 10 comprising a drive motor and a transmission (both not shown in this figure) is by means of a holding device 31 held so movably that the arrangement 10 a radial movement and / or a bending movement of the adjusting shaft 2 can follow.

Also in 5 illustrated embodiment includes a particularly advantageous manner on the one hand radially flexible and / or transversely to the axial direction bendable and torsionally stiff Clutch. It should be noted, however, that this solution can also be implemented independently of such a coupling.

LIST OF REFERENCE NUMBERS

1

internal combustion engine

2

adjusting

3

Verstellpleuel

4

adjusting

5

piston

6

pleuel

7

lifting arm

8th

crankshaft

9

End region of the adjusting shaft 2

10

Arrangement for adjusting the rotational position of the adjusting shaft 2

11

drive motor

12

backlash-free transmission

13

Tension shaft gear

14

wave generator

15

roller bearing

16

flexpline

17

Dynamicsplline

18

Circularspline

19

clutch

20

Steel lamina coupling

21

first sliding bearing

22

gearbox

23

coupling plate

24

second sliding bearing

25

crankcase

26

belt drive

27

first pulley

28

second pulley

29

belt

30

further rolling bearings

31

holder

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 102011116952 A1 [0002]
• EP 2022959 A2 [0003]

Claims (15)

Arrangement for driving an adjusting shaft for adjusting the expansion stroke and / or the compression ratio of an internal combustion engine, wherein the arrangement comprises a drive motor and a drive connected downstream of the drive motor, characterized in that a. On the gearbox output side on the one hand radially flexible and / or transversely to the axial direction bendable and on the other hand torsionally stiff coupling is connected to the transmission, or that b. the transmission is arranged and adapted to be connected via an on the one hand radially flexible and / or axially bendable and torsionally rigid coupling to an adjusting for adjusting the expansion stroke and / or the compression ratio of an internal combustion engine. Arrangement according to claim 1, characterized in that the coupling is designed as a dog clutch or as a multi-plate clutch or as a flexible shaft coupling or Oldham coupling or bellows coupling. Arrangement according to claim 1 or 2, characterized in that the transmission is designed as a backlash-free transmission. Arrangement according to claim 3, characterized in that a. the transmission is designed as a voltage wave transmission or that b. the transmission is designed as a voltage wave transmission, namely in the form of a ring gear, or that c. the transmission is designed as a voltage wave transmission, namely in the form of a pot gear. Arrangement according to one of claims 1 to 4, characterized in that the transmission is designed as a tension shaft gear and that a connected to the transmission output dynamic spline or connected to the transmission output circular spline, in particular exclusively, is slidably mounted. Arrangement according to one of claims 1 to 5, characterized in that the drive motor and the transmission are arranged in a common housing. Arrangement according to one of claims 1 to 6, characterized in that the drive motor and the gearbox are arranged coaxially to each other or that the drive motor and the gear are arranged axially parallel to each other. Arrangement according to one of claims 1 to 7, characterized by a locking device for blocking a rotational movement of a rotary component of the drive motor or the transmission. Arrangement according to claim 8, characterized in that the locking means comprises a movable locking bolt which is movable for blocking a rotational movement of the rotary member from a release position into a blocking position, in which the locking bar engages in a locking receptacle of the rotary member. Internal combustion engine with an adjusting shaft for adjusting the expansion stroke and / or the compression ratio, characterized in that an arrangement according to one of claims 1 to 9 is connected to the adjusting shaft. Internal combustion engine according to claim 10, characterized in that the adjusting shaft is connected via an on the one hand radially flexible and / or axially bendable and on the other hand torsionally rigid coupling to the arrangement. Internal combustion engine according to claim 10 or 11, characterized in that the arrangement or at least a part of the arrangement is supported movably by means of a holding device, that the arrangement or at least a part of the arrangement of a radial movement and / or a bending movement of the adjusting follow. Internal combustion engine according to claim 12, characterized in that a. a torque support is provided, by means of which a torque acting on the adjusting shaft when applying a torque counter-torque in a housing of the internal combustion engine and / or in a vehicle body is derived, wherein the torque support is arranged and configured such that the arrangement or at least a part can follow the arrangement of a radial movement and / or a bending movement of the adjusting and / or that b. the holding device acts as a torque support, by means of which a counter-torque acting on the arrangement when applying a torque to the arrangement counter-torque in a housing of the internal combustion engine and / or in a vehicle body can be derived. Internal combustion engine according to one of claims 10 to 13, characterized in that a. an adjustment of the expansion stroke and / or the compression ratio exclusively at a given or specifiable phasing of the crankshaft of the internal combustion engine is possible and / or that b. the arrangement, in particular the drive motor, can be activated exclusively in the case of a predetermined or predefinable phase angle of the crankshaft of the internal combustion engine. Internal combustion engine according to one of claims 10 to 14, characterized in that the internal combustion engine comprises a multi-joint crank drive.

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