DE102015017286B3 - Actuator, in particular for coupling to the adjustment shaft of an internal combustion engine for setting the expansion stroke and/or the compression ratio - Google Patents

Abstract

Actuator (1), which has a drive motor (2), a gear (5) downstream of the drive motor (2) and a driven element (6), characterized by a fastening screw (21) for fastening the driven element (6) to a Drive shaft (20) to be driven by the actuator (1) of a system to be driven without dismantling the actuator (1) or dismantling parts of the actuator (1), the fastening screw (21) being designed and arranged in such a way that it cannot be removed, when the actuator (1) is not coupled to a system to be driven, without dismantling or destroying parts of the actuator (1) for this purpose.

Description

The invention relates to an actuator which has a drive motor, a gear mechanism downstream of the drive motor and an output element.

The invention also relates to an actuator system with such an actuator and with a sensor for measuring a rotational position and/or the number of revolutions.

The invention also relates to a drive system with such an actuator, which is coupled to an internal combustion engine of the drive system for changing the expansion stroke and/or the compression ratio of the internal combustion engine.

Out of DE 10 2011 116 952 A1 is a multi-joint crank mechanism of an internal combustion engine, with a plurality of coupling links rotatably mounted on crankpins of a crankshaft and a plurality of linking connecting rods rotatably mounted on crankpins of an eccentric shaft, each of the coupling links being pivotably connected to a piston connecting rod of a piston of the internal combustion engine and one of the linking connecting rods and the angular position of the Eccentric shaft is adjustable by means of an adjusting device within a certain angle of rotation range, known. It is provided that the eccentric shaft can be fixed in at least one rotational angle locking position by means of a locking device. In concrete terms, it is proposed that the adjusting device has a gear with a drive wheel arranged in a rotationally fixed manner on the eccentric shaft. In particular, the gear is a worm gear, with the output gear being designed as a worm gear.

Out of EP 2 022 959 A2 a device for variably adjusting the compression is known, which has a multi-joint crank mechanism and in which an adjusting device for adjusting the angle of rotation of an eccentric shaft comprises a lever arrangement. The eccentric shaft can be rotated via the lever arrangement and thus a desired rotational angle position can be set.

DE 10 2011 120 162 A1 discloses an internal combustion engine with a variable compression ratio. The internal combustion engine has a cylinder crankcase with a plurality of connecting rods mounted on a crankshaft and carrying a reciprocating piston. The crankshaft bearings are mounted eccentrically and are non-rotatably connected to one another. At least one gear wheel segment is fastened to one of the axially outer crankshaft bearings, the gear wheel acting on the gear wheel segment in order to introduce a torque in order to adjust the eccentric crankshaft bearing. In this case, the gear wheel engages in the gear wheel segment perpendicular to an axis of rotation of a crankshaft and at right angles to a cylinder axis of the cylinder crankcase.

DE 10 2010 062 047 A1 discloses a device for reducing backlash in a transmission, particularly in a transmission for varying the compression ratio of an internal combustion engine with a variable compression ratio.

EP 1 450 021 A1 discloses a reciprocating engine with a variable compression ratio. The device also discloses an oil lubrication system. Depending on the compression ratio, the engine is lubricated with oil using the oil lubrication system. The compression ratio is set and the oil pressure is controlled by an electronic engine control unit.

Out of DE 10 2011 116 429 A1 a control device for variably setting at least one compression ratio of an internal combustion engine, in particular a reciprocating piston internal combustion engine, is known. The adjusting device has at least one gear, via which the compression ratio can be adjusted and which comprises a sun gear, a first ring gear, a second ring gear arranged coaxially to the first ring gear and at least one planetary gear element which meshes with the sun gear and with the ring gears via respective toothings , wherein the ring gears are clamped together in the axial direction by means of at least one spring element.

The disadvantage of the known devices is their construction is very complex. in particular, it is expensive to couple the actuators to an internal combustion engine.

It is therefore the object of the present invention to specify an actuator that can be installed more easily and reliably.

The object is achieved by an actuator, which is characterized by a fastening screw for fastening the driven element to a drive shaft of a system to be driven, which is to be driven by means of the actuator, without disassembling the actuator or dismantling parts of the actuator, the fastening screw being designed in this way and in this way in the actuator is arranged so that it cannot be removed when the actuator is not coupled to a system to be driven without dismantling or destroying parts of the actuator.

In this way, it is avoided that the fastening screw accidentally gets lost, for example during transport from the manufacturer of the actuator to a user who couples the actuator to an internal combustion engine. The captive arrangement of the fastening screw can be achieved, for example, by a collar that limits the axial mobility of the fastening screw. For example, it can advantageously be provided that the collar strikes a constriction of the hollow shaft when the fastening screw running through a hollow shaft is displaced in the direction of the drive motor, and strikes the output element when it is displaced in the opposite direction. The collar can in particular be a collar which is designed and arranged to press the driven element onto the drive shaft to be driven, in particular the end face of the drive shaft to be driven, which is explained in detail further below.

In a particularly advantageous embodiment, it is provided - according to an independent inventive concept - that the entire actuator can be coupled as a fully assembled and functional unit to a system to be driven by the actuator, which has a drive shaft, with a torsionally rigid connection of the output element to the drive shaft can be produced without having to dismantle parts of the actuator for this purpose.

This has the very particular advantage that the actuator can be coupled to a system to be driven by the user as an independent unit that has been fully assembled by the manufacturer and tested for proper functionality.

According to the invention, it is advantageously not necessary to disassemble the actuator for coupling to a system to be driven, which on the one hand simplifies the assembly process itself and also ensures that the actuator is used in the state in which it is functional, in particular tested immediately after its manufacture.

As described in detail below, the system to be driven by the actuator can be, for example, an internal combustion engine, in particular an internal combustion engine for a motor vehicle, in which case the actuator according to the invention can be used to set the expansion stroke and/or the compression ratio of the internal combustion engine. Advantageously, in a special embodiment, the actuator according to the invention can be coupled to the internal combustion engine as an independent and fully functional structural unit and operatively connected to an adjustment shaft of the internal combustion engine without the fitter who is assembling the drive system and/or a motor vehicle with such a drive system having to remove the actuator beforehand has to be disassembled and/or assembled in individual parts on the internal combustion engine.

The fastening screw can in particular have a metric thread, for example an M10 thread. The output element can, as will be described in detail further below, in particular be an output of the transmission, which is designed in particular to be flexible and at the same time torsionally rigid.

In particular, it can advantageously be provided that the fastening screw runs both through the transmission and through the drive motor. Alternatively or additionally, the head of the fastening screw and the driven element can be arranged on opposite sides of the actuator. These designs have the particular advantage that the output element can also be reliably fastened to a drive shaft of a system to be driven if other elements of the transmission and/or the drive motor are positioned in front of it and prevent the output element from being reached directly.

In a special embodiment, the actuator has a fastening channel through which the fastening screw for fastening the driven element to a drive shaft to be driven by the actuator can be guided and/or through which a tool for rotating the fastening screw can be guided. In such an embodiment, a fastening screw can also be used, for example, which does not extend through the entire actuator in the assembled state. Rather, it is also entirely possible to use a shorter fastening screw, in particular a standard screw. Such a fastening screw can be operated, for example, with a sufficiently long tool, the free end of which is guided through the fastening channel to the fastening screw when coupling the driven element to the drive shaft of the system to be driven.

In a special embodiment, the fastening channel is delimited by a sleeve, in particular a circular-cylindrical sleeve. In addition, the sleeve can also have the function of delimiting the fastening channel from different spaces of the actuator, in particular from a space flushed through with oil, which is explained in detail further below. In particular, the sleeve can provide one or more sealing surfaces that are in contact with seals, which is also explained in more detail below.

The sleeve can, for example, be arranged in a stationary manner relative to an actuator housing and, in particular, can be connected directly to an actuator housing. Alternatively, it is also possible, for example, for the sleeve to be stationary relative to the driven element. Alternatively or additionally, it can also be provided that the sleeve is arranged coaxially to the gear and/or coaxially to the drive motor.

In a special embodiment, the sleeve runs both through the gearbox and through the drive motor. In particular, it can advantageously be provided that the inlet opening of the fastening channel and the driven element are arranged on opposite sides of the actuator.

In a particular embodiment, the fastening screw is arranged coaxially and/or on the central axis of the actuator. Such an embodiment advantageously makes it possible to arrange the components of the actuator, in particular the drive motor and the transmission, coaxially with one another, which makes a compact design possible overall.

In a special embodiment, the fastening screw is designed and arranged to be connected to the driven element in a rotationally fixed manner when the actuator is installed on a system to be driven. Alternatively or additionally, the fastening screw can advantageously be designed and arranged to be screwed into a drive shaft to be driven, in particular on the front side.

For example, the fastening screw can have a collar spaced axially from the head, which is designed and arranged to press the output element against the drive shaft to be driven, in particular the end face of the drive shaft to be driven.

The collar can be made in one piece with the fastening screw or at least with the shank of the fastening screw. However, it is also possible for the collar to be attached to the fastening screw as an independently manufactured component, for example as a clip or disk, in particular in a non-detachable manner.

In a particularly advantageous embodiment, the fastening screw protrudes from an actuator housing of the actuator in the unmounted state of the actuator, while in the mounted state, ie when the actuator is connected to a system to be driven, it terminates flush with the actuator housing. In this way, the fitter can visually check whether the actuator has been correctly connected.

Regardless of the coupling of the output element to the drive shaft of the system to be driven, the actuator housing can, for example, have one fastening element or several fastening elements for fastening to the system to be driven, for example to a housing of the system to be driven or an engine block. The fastening element can have, for example, a fastening eyelet through which a screw can be passed and/or a flange.

In a particularly advantageous embodiment, the fastening screw is designed for coupling a sensor that measures the rotational position and/or the number of revolutions of the fastening screw relative to an actuator housing or relative to a component of the actuator that is fixed to the actuator housing. In this way, the fastening screw rotating with the driven element can fulfill the additional function of transmitting the rotational movement of the driven element and thus the rotational movement of the drive shaft of the driven system to a sensor. In particular, the sensor can be coupled to the head of the fastening screw. Such an embodiment makes it possible in particular to arrange the sensor outside of an actuator housing of the actuator, in particular on the outside of the actuator housing. A sensor arranged in this way is particularly easy to access for assembly and/or repair work. In particular, it is also possible to attach the sensor after the actuator has been coupled to a system to be driven.

As an alternative to a fastening screw, it can also be provided that the output element is connected in a torque-proof manner to the drive shaft of the system to be driven, for example an adjusting shaft of an internal combustion engine, by means of a plug connection. For example, the driven element can have two eccentrically arranged bolts, which engage in two end-side fits of the shaft to be driven. However, such a solution is critical insofar as the output element and the drive shaft to be driven can have axial play with respect to one another.

As already mentioned, the actuator can be coupled in particular to an adjustment shaft of an internal combustion engine, the rotational position of which determines the expansion stroke and/or the compression ratio of the internal combustion engine. In order to control the internal combustion engine, it is necessary for the current setting of the expansion stroke and/or the compression ratio to be continuously measured and monitored. For this purpose, the internal combustion engine usually includes its own sensor that determines the rotational position of the Ver control shaft continuously measures. The above-described coupling of a sensor to the actuator, which measures the rotational position and/or the number of revolutions of the fastening screw relative to an actuator housing or relative to a component of the actuator fixed to the actuator housing, can - according to an independent inventive idea - advantageously be attached to a separate sensor , which is arranged in the internal combustion engine, are dispensed with. Rather, the rotational position and/or the number of revolutions of the adjusting shaft can be measured and monitored reliably by means of the sensor coupled to the fastening screw. In this respect, in a drive system that has an internal combustion engine, an actuator according to the invention, and a sensor coupled to the fastening screw, it can be advantageously provided that the internal combustion engine does not have a sensor for measuring the rotational position of the adjustment shaft and/or that a control device records the current setting of the expansion stroke and/or the compression ratio of the internal combustion engine is determined exclusively by means of the sensor coupled to the fastening screw.

It would also be possible to measure the rotational position of the output element and thus the adjustment shaft of the internal combustion engine indirectly by detecting the revolutions of the drive motor using a speed sensor and deducing the angular position of the output element via the reduction ratio of the transmission. In practice, however, this would not be sufficiently reliable because a value is also returned if the drive motor is functioning but, for example due to a defect, no torque is being transmitted to the output element and/or the adjusting shaft of the internal combustion engine. However, this problem does not exist if the rotational position and/or the number of turns of the fastening screw are measured directly.

In a particularly advantageous embodiment, the actuator has two spaces that are sealed relative to one another, it being possible in particular to provide for the transmission to be located in one of the spaces and the drive motor or at least parts of the drive motor or a speed sensor to be located in the other of the spaces / or measures the number of revolutions of the output shaft of the drive motor are arranged. The speed sensor can be present in particular in addition to the above-mentioned sensor, which measures the rotational position and/or the number of revolutions of the fastening screw.

The actuator can have two spaces that are sealed relative to one another, one of which is designed and arranged to be connected to an oil lubrication system, in particular an oil lubrication system of the system to be driven. In particular, the gear or at least parts of the gear can be arranged in this space, which has the advantage that sufficient lubrication of the gear is ensured.

For example, if the system to be driven is designed as an internal combustion engine, there is the problem that the pressurized engine oil or the dirt and abrasion particles transported by it, which can have up to 5 bar in a car engine, could also get into areas of the actuator where it can do harm. These include, in particular, the actuator electronics and the area of the speed sensor, which detects the number of revolutions of the output shaft of the drive motor and/or the angular position of the output shaft of the drive motor. For this reason, it can advantageously be provided that these areas are protected by means of seals, in which case at least one seal can be arranged, in particular also in the area of the fastening screw, which is explained below.

In a special embodiment, the actuator has two spaces that are sealed relative to one another, one of the spaces being filled with a gas, in particular with air. Electronic components in particular, such as a speed sensor, which measures the rotational position and/or the number of revolutions of the output shaft of the drive motor, can be located in this space. In particular, it can also be provided that the drive motor or at least parts of the drive motor are located in this space. As described above, the other of the two spaces can advantageously contain the gearbox or parts of the gearbox and/or be connected to an oil lubrication system.

For example, if the actuator is constructed in such a way that the drive motor is located in one of the spaces and the downstream transmission is located in the other space that is exposed to oil, it is necessary to close the spaces in the area of the output shaft of the drive motor and/or in the area seal the drive shaft of the transmission relative to each other. In this case, the fact that the seal must be arranged between components that move relative to one another at high speed during operation must be taken into account. In that regard, the spaces are sealed relative to each other in a particular embodiment by means of at least one seal, which is a non-abrasive seal and/or a dynamic seal and/or a rotary seal and/or a gap seal and/or a seal that uses a centrifugal effect for sealing, and/or is designed as a labyrinth seal. This ensures that the seal has a sufficiently long service life despite the relative movement.

In particular, it can advantageously be provided that the seal on the one hand bears against the fastening screw and/or interacts with the fastening screw and on the other hand bears on the inside of a hollow shaft and/or interacts with a hollow shaft. The hollow shaft can in particular be the drive shaft of the transmission and/or the output shaft of the drive motor. Alternatively, it is also possible for the hollow shaft to be connected in a torque-proof manner to an input shaft of the transmission or an output shaft of the drive motor. The seal can in particular bear against the inside of a hollow shaft and/or interact with a hollow shaft which is connected in a torque-proof manner to a wave generator of the transmission designed as a voltage wave transmission.

In order to be able to mount an annular seal, the fastening screw can have a thickened diameter in the sealing area, the diameter there being greater than or equal to the diameter of the head of the fastening screw. In this way, the fastening screw can be installed together with the seal when the drive motor and transmission are assembled, namely, in particular, the head of the fastening screw can be inserted through the seal.

Alternatively, a multi-part seal, for example a seal that can be assembled from two half-segments, could be used.

The use of a hollow shaft has the particular advantage that the fastening screw, in particular the shank of the fastening screw, can run through the interior of the hollow shaft.

As already mentioned, it can advantageously be provided that the actuator provides a fastening channel which is delimited, in particular radially, by a sleeve. It is also possible in such an embodiment for the actuator, as described above, to have two spaces that are sealed relative to one another. At least one seal can be provided to seal off the spaces from one another, which seal bears against the sleeve, in particular on the outside or the end face of the sleeve, and/or interacts with the sleeve. If a seal is arranged on the one hand between the output shaft of the drive motor and/or the input shaft of the gearbox and the sleeve on the other hand, account must be taken of the fact that the seal is arranged between components which move relative to one another at high speed during operation. In this respect, it is advantageous to use a seal that is designed as a non-abrasive seal and/or as a dynamic seal and/or as a rotary seal and/or as a gap seal and/or as a seal that uses a centrifugal effect for sealing and/or as a labyrinth seal is. This ensures that the seal has a sufficiently long service life despite the relative movement.

Regardless of the seal described above, which seals different spaces of the actuator from one another, a housing seal can advantageously be present, which seals the actuator housing, in particular the gas-filled space of the actuator, from the space surrounding the actuator. This advantageously prevents, for example, dirt from penetrating into the gas-filled space of the actuator. In particular, the housing seal can on the one hand bear against an actuator housing of the actuator and/or interact with an actuator housing of the actuator and on the other hand bear against the fastening screw, in particular the head of the fastening screw, and/or interact with the fastening screw, in particular with the head of the fastening screw.

For example, a housing seal can be provided in the area of the head of the fastening screw, which seals between the head and the actuator housing. Advantage is taken of the fact that the head of the fastening screw executes only small and slow angles of rotation relative to the actuator housing. Therefore, in particular, a rubbing seal can also be used here.

In a particularly advantageous embodiment, the fastening screw provides at least one sealing surface for the seal and/or the housing seal, in particular in the area of the shaft and/or in the area of the head. The fastening screw preferably has no thread in the area of the sealing surface. In this respect, the fastening screw - according to an independent inventive idea - not only fulfills the function of enabling the output element to be coupled to the adjustment shaft of the internal combustion engine, but also the function of being part of a sealing system or several sealing systems.

The transmission can advantageously be designed as a tension shaft transmission. In particular, the transmission can advantageously be designed as a tension shaft transmission in the form of a ring transmission. In particular, it can advantageously be provided that the output element has an internally toothed ring gear.

However, it is also possible, for example, for the transmission to be of a different type of transmission. For example, the gear can also be designed as a planetary gear.

However, it has been recognized that the forces and torques occurring when an actuator is coupled to a coupling end of a shaft to be driven, which executes oscillating movements, such as wobbling movements, in the radial and/or axial direction, have a particularly disadvantageous effect the greater the play in the transmission . It was therefore further recognized that the basic use of a stress shaft transmission, which is naturally free of backlash, is particularly advantageous for such applications, which also include the coupling to an adjustment shaft of an internal combustion engine for setting the expansion stroke and/or the compression ratio.

A stress wave transmission is usually constructed in such a way that it has a rigid, circular and internally toothed ring gear, which is referred to as a circular spline, and a radially flexible externally toothed gear, which is arranged inside the rigid internally toothed ring gear and is referred to as a flexspline. In the externally toothed gear, a mostly elliptical wave generator is rotatably arranged by means of a rolling bearing, which deforms the radially flexible externally toothed gear into an elliptical shape to mesh the teeth of the internally toothed gear and the radially flexible externally toothed gear at each end of the ellipse major axis.

In particular, a stress wave gear with a wave generator, an externally toothed flexspline and an internally toothed ring gear meshing with the flexspline can advantageously be used as the gear. In particular, it can advantageously be provided that the stress shaft transmission for transmitting torque to a shaft to be driven, the coupling end of which executes an externally driven axial and/or radial movement, contains an output element having the ring gear, which is torsionally rigid and at the same time flexible, and the other parts of the actuator at least partially, in particular completely, decoupled from the externally driven axial and/or radial movement. In particular, the driven element can advantageously have a torsionally rigid and at the same time flexible driven bell.

In addition to the freedom from backlash, which essentially protects the stress shaft transmission itself from damage, the preferably flexible and torsionally rigid, pot-shaped output bell of the output element protects the other parts of the actuator in particular from damage caused by radial and/or axial vibrational movements, in particular wobbling movements, of the coupling end of the shaft to which the actuator is coupled.

The output element can advantageously have an output shaft. In particular, it can advantageously be provided that the output shaft is fastened by means of the fastening screw to the shaft to be driven of the system to be driven by means of the actuator. For this purpose, the output shaft can have a particularly coaxial and/or central through hole through which the fastening screw runs, it being possible in particular for the output shaft to be clamped between a collar of the fastening screw and the shaft to be driven.

Preferably, the ring gear is rotatable by means of a ring gear bearing arrangement relative to a housing and/or the axis of symmetry of the tension shaft transmission, but is mounted in a stationary manner.

For the purposes of the present invention, the term "output bell" means a component that is suitable and arranged to transmit torque from the ring gear to an output shaft, with the output bell not necessarily having the shape of a classic bell, such as a church bell. needs to show. For example, it can also be pot-shaped and/or asymmetrical. The output bell does not necessarily have to be rotationally symmetrical. For example, the output bell can also have a plurality of spokes which are arranged at least partially radially. In particular, the output bell does not necessarily have to have a closed wall. However, a rotationally symmetrical design of the output bell, in particular in the form of a pot or in a classic bell shape, is particularly advantageous since an imbalance is avoided with such a design and the radial and/or axial forces to be absorbed always cause the same deformation regardless of the rotational position.

The flexspline and the shaft generator and/or a Dynamicspline and/or a ring gear bearing are effectively separated from the radial and/or axial movements, in particular wobbling movements, which the drive shaft of the coupled system, in particular an adjusting shaft for adjusting the expansion stroke and/or the compression compression Ratio, performs, at least largely, decoupled without the backlash-free transferability of torque from the tension shaft gear to the drive shaft is adversely affected. The ring gear bearing, which can in particular be designed as a slide bearing, must therefore at most absorb a small remaining portion of the radial and/or axial movements, in particular wobbling movements.

In a particularly advantageous embodiment, an output component of the drive motor and a drive component of the transmission are designed as separately manufactured components that are connected to one another in a torque-proof manner. In particular, it can advantageously be provided that the driven component of the drive motor and the drive component of the transmission are connected to one another in a torque-proof manner by means of at least one clamping component. The clamping component can be designed, for example, as a corrugated and/or elastic and/or cylindrically bent strip, in particular sheet metal strip, and/or as a slotted ring and/or as a corrugated cylindrical spring tube. Such an embodiment has the very special advantage that the drive motor and the transmission can be manufactured separately from one another, in particular on different production lines, which makes the manufacturing process of the actuator more efficient overall. For example, a drive component of the transmission, in particular the shaft generator, can have a recess into which the output component of the drive motor, namely an output shaft and the clamping component, are inserted and thus connected to one another by friction. A particularly good clamping effect, in which slipping is reliably prevented and which is nevertheless easy to assemble, has an embodiment in which several clamping components are mechanically connected in parallel for the torsionally rigid coupling of the output shaft of the drive.

As already mentioned, a drive system, in particular for a motor vehicle and/or a passenger car, is of particular advantage which has an internal combustion engine and an actuator according to the invention coupled to the internal combustion engine for changing the expansion stroke and/or the compression ratio of the internal combustion engine. It can be particularly advantageous here for the internal combustion engine to have an adjustment shaft, in which case the expansion stroke and/or the compression ratio of the internal combustion engine can be changed by changing the rotational position of the adjustment shaft, and the output element is connected to the adjustment shaft in a rotationally fixed manner and/or is arranged coaxially with the adjustment shaft . As also already mentioned, it can advantageously be provided that the internal combustion engine does not have a sensor for measuring the rotational position of the adjusting shaft, and/or that a control device determines the current setting of the expansion stroke and/or the compression ratio of the internal combustion engine exclusively by means of a sensor coupled directly to the actuator determined. In addition, the actuator can advantageously be connected, at least partially, to the oil supply system of the internal combustion engine.

A motor vehicle that contains an actuator according to the invention and/or a drive system according to the invention is of particular advantage.

• 1 ein erstes Ausführungsbeispiel eines erfindungsgemäßen Aktuators,
• 2 ein Ausführungsbeispiel eines erfindungsgemäßen Aktuatorsystems mit einem Aktuator mit einem Sensor,
• 3 ein Ausführungsbeispiel eines erfindungsgemäßen Antriebssystems,
• 4 ein zweites Ausführungsbeispiel eines erfindungsgemäßen Aktuators,
• 5 ein drittes Ausführungsbeispiel eines erfindungsgemäßen Aktuators, und
• 6 ein viertes Ausführungsbeispiel eines erfindungsgemäßen Aktuators.

The subject of the invention is shown schematically and by way of example in the drawing and is described below with reference to the figures, with elements that are the same or have the same effect are usually provided with the same reference symbols. show:

• 1 a first embodiment of an actuator according to the invention,
• 2 an embodiment of an actuator system according to the invention with an actuator with a sensor,
• 3 an embodiment of a drive system according to the invention,
• 4 a second embodiment of an actuator according to the invention,
• 5 a third embodiment of an actuator according to the invention, and
• 6 a fourth embodiment of an actuator according to the invention.

1 shows a first exemplary embodiment of an actuator 1 according to the invention, which includes a drive motor 2 with a rotor 3 and a stator 4 . In addition, the actuator 1 includes a drive motor 2 downstream transmission 5, which is arranged coaxially to the drive motor 2 and has an output element 6. The rotor 3 is connected in a torque-proof manner to a hollow shaft 7, which acts as the output shaft of the drive motor 2 and drives a shaft generator 8 of the transmission 5 designed as a tension shaft transmission and is connected to it in one piece. The hollow shaft 7 is rotatably mounted by means of two roller bearings 18.

The tension shaft transmission has an externally toothed, ring-shaped Flexspline 9 . The shaft generator 8 is rotatably mounted in the ring-shaped Flexspline 9 by means of two roller bearings 10, 11 and deforms it into an oval shape in such a way that the Flexspline 9 with its external toothing fits into the internal toothing of a first ring gear, namely a Dynamicspline 12, as well as engages in the internal toothing of a second ring gear, namely a circular spline 13 . The dynamic spline 12 is fastened in an actuator housing 14 in a rotationally fixed manner.

The tension shaft transmission has an output element 6 , which has the circular spline 13 and a pot-shaped output bell 16 connected to it in a torque-proof manner, as well as an output shaft 17 . The output bell 16 is produced in one piece together with the circular spline 13 and the output shaft 17 . The output bell 16 is designed to be flexible and at the same time torsionally rigid.

The entire actuator 1 can be coupled as a fully assembled and functional unit to a system 19 which is to be driven by the actuator 1 and which has a drive shaft 20, with a torsionally rigid connection of the output element 6 to the drive shaft 20 being able to be established without having to dismantle parts of the actuator for this purpose must. The drive shaft 20 can be, for example, an adjustment shaft for adjusting the expansion stroke and/or the compression ratio of an internal combustion engine.

The actuator has a fastening screw 21 for fastening the driven element 6 to the drive shaft 20 to be driven by the actuator 1 . The fastening screw 21 has a thread 15 and is screwed into a threaded bore 29 of the drive shaft 20 at the end, as a result of which the output shaft 17 of the output element 6 is clamped between a collar 28 and the end of the drive shaft 20 .

The fastening screw 21 is arranged centrally and coaxially with both the gear 5 and the drive motor 2 and runs through both the gear 5 and the drive motor 2. The head 22 of the fastening screw 21 and the driven element 6 are on opposite sides of the actuator arranged.

The actuator 1 has two spaces that are sealed relative to one another, with the gear 5 in one of the spaces and the drive motor 2 in the other of the spaces, as well as a speed sensor 23, which measures the rotational position and/or the number of revolutions of the hollow shaft 7 of the drive motor 2 , are arranged. The space of the actuator 1 in which the transmission 5 is arranged is designed and arranged to be connected to an oil lubrication system, in particular an oil lubrication system of the system 19 to be driven. The space in which the transmission 5 is arranged is sealed by means of a first seal 24 and by means of a second seal 25 relative to the space in which the drive motor 2 and a speed sensor 23 are arranged. The seals are designed as non-rubbing seals to account for the fact that they are each in contact with components that move relative to one another at high speeds. The first seal 24 is spatially located between the wave generator 8 and a partition wall 26.

The second seal 25 bears on the fastening screw 21 on the one hand and on the inside of the hollow shaft 7 on the other hand. In the area of the second seal 25, the fastening screw 21 has a thickened diameter 27, so that the second seal 25 can have such a large internal diameter that the head 22 of the fastening screw 21 can be inserted through the second seal 25 when the actuator 1 is assembled.

Regardless of the seals 24 , 25 described above, which seal the different spaces of the actuator from one another, there is a housing seal 30 which seals the actuator housing 14 from the space surrounding the actuator 1 . The housing seal 30 rests against an actuator housing 14 on the one hand and against the head 22 of the fastening screw 21 on the other hand. Advantage is taken of the fact that the head 22 of the fastening screw 21 executes only small and slow angles of rotation relative to the actuator housing 14 . Therefore, in particular, a rubbing seal can also be used as the housing seal 30 .

The fastening screw 21 is designed and arranged in the actuator 1 in such a way that it cannot be removed from the actuator 1 without dismantling or destroying parts of the actuator 1 for this purpose. This is also the case, in particular, when the actuator 1 is not yet coupled to a system 19 to be driven. The captive arrangement of the fastening screw 21 is achieved in particular by the collar 28 which limits the axial mobility of the fastening screw 21 . If the actuator 1 is not yet coupled to a system 19 to be driven, the collar 28 strikes a constriction 31 of the hollow shaft 7 when the fastening screw 21 is displaced in the direction of the drive motor 2, while it strikes the output element 6 strikes.

2 shows an embodiment of an actuator system according to the invention with an actuator 1 as shown in 1 is shown and with a sensor 32 which measures the rotational position and/or the number of revolutions of the fastening screw 21 relative to the actuator housing 14 . The sensor 32 is coupled to the head 22 of the fastening screw 21 and its Housing 33 attached to the actuator housing 14. In particular, a magnetic encoder element 34 can be attached to the head 22 , the rotational position of which is detected by a detector element 35 of the sensor 32 . In this way, the fastening screw 21 rotating with the driven element 6 fulfills the additional function of transmitting the rotational movement of the driven element 6 and thus the rotational movement of the drive shaft 20 of the driven system 19 to the sensor 32 .

3 shows schematically an exemplary embodiment of a drive system according to the invention, in particular for a motor vehicle and/or a passenger car, which has an internal combustion engine 36 and an actuator 1 according to the invention coupled to the internal combustion engine 36 for changing the expansion stroke and/or the compression ratio of the internal combustion engine 36.

A sensor 32 is arranged on the fastening screw 21 and measures the rotational position and/or the number of revolutions of the fastening screw 21 and thus of a coupled adjustment shaft 37 relative to the actuator housing 14 and transmits the measured value to an electronic control device 38 . The control device 38 controls further settings of the internal combustion engine, such as the ignition point and/or the camshaft setting, taking into account the transmitted measured value. The fastening screw 21 rotating with the adjusting shaft 37 fulfills the additional function of transmitting the rotary motion of the driven element and thus the rotary motion of the adjusting shaft to the sensor 32 .

Due to the above-described coupling of sensor 32 to actuator 1, which measures the rotational position and/or the number of revolutions of fastening screw 21 relative to actuator housing 14, a separate sensor, which is arranged in internal combustion engine 36, can advantageously be dispensed with . In this respect, it can advantageously be provided that the internal combustion engine 36 does not have its own sensor for measuring the rotational position of the adjustment shaft 37 and that the control device 38 determines the current setting of the expansion stroke and/or the compression ratio of the internal combustion engine 36 exclusively by means of the sensor coupled to the fastening screw 21 .

4 12 shows a second exemplary embodiment of an actuator 1 according to the invention. In this exemplary embodiment, the actuator 1 has a fastening channel 39 through which a fastening screw 21 to the driven element 6 can be guided. In addition, a tool for rotating the fastening screw 21 can be inserted through the fastening channel 39 . In this embodiment, the fastening screw 21 does not extend through the entire actuator 1 in the assembled state. Rather, the fastening screw 21 is shorter than the fastening screw 21 of the in 1 illustrated first embodiment. In particular, the fastening screw 21 can be designed as a standard screw. Between the head 22 of the fastening screw 21 and the output shaft 17 is a, in particular standardized, washer 40 is arranged.

The fastening screw 21 can be operated with a sufficiently long tool, the free end of which is guided through the fastening channel 39 to the head 22 of the fastening screw 21 when the driven element 6 is coupled to the drive shaft 20 of the system 19 to be driven.

The fastening channel 39 is delimited by a circular-cylindrical sleeve 41 . The sleeve also has the additional function of delimiting the fastening channel 39 from different spaces of the actuator 1 . The sleeve 41 provides a sealing surface on the outside and on the front. A first seal 42 rests on the front sealing surface and is also in contact with the driven element 6 . A second seal 43 is located on the outside sealing surface, which is also in contact with the hollow shaft 7 and is preferably designed as a non-abrasive seal.

The sleeve 41 is arranged stationary relative to an actuator housing 14 and is connected directly to the actuator housing 14 . The sleeve 41 runs both through the gear 5 and through the drive motor 2, with the input opening 44 of the fastening channel 39 and the output element 6 being arranged on opposite sides of the actuator 1. The inlet opening 44 of the fastening channel 39 is closed with a removable cover 45, which prevents the fastening screw 21 from being lost before the actuator 1 is coupled to a system 19 to be driven and which prevents the ingress of dirt when the actuator 1 is in the installed state.

5 shows a third exemplary embodiment of an actuator 1 according to the invention. In this embodiment, the hollow shaft 7, as the output component of the drive motor 2, and the shaft generator 8 are designed as separately manufactured components which are connected to one another in a torque-proof manner. The wave generator 8 has a central recess into which the hollow shaft 7 is inserted in a frictionally engaged and non-rotatable manner with the aid of a clamping component 46 . The clamping component 46 can, for example, as a corrugated and / o the elastic and/or cylindrically bent strip, in particular sheet metal strip, and/or be designed as a slotted ring and/or as a corrugated cylindrical spring tube.

6 shows a fourth exemplary embodiment of an actuator 1 according to the invention, which corresponds to that in 1 shown, first embodiment is similar. In contrast to the in 1 illustrated embodiment, the hollow shaft 7 is rotatably mounted with a first sealed bearing 47, which replaces the first seal 24 present in the first embodiment with regard to the sealing function. In addition, the fastening screw 21 does not have the thickened diameter 27 that the fastening screw 21 of the first exemplary embodiment has. The second seal 25 is also not present. Rather, the fastening screw 21 is rotatably mounted relative to the hollow shaft 7 by means of a second sealed bearing 48, so that the second sealed bearing 48 takes over the sealing function that the second seal 25 performs in the first exemplary embodiment.

Reference List

1

actuator

2

drive motor

3

rotor

4

stator

5

transmission

6

output element

7

hollow shaft

8th

wave generator

9

flexspline

10

roller bearing

11

roller bearing

12

dynamic spline

13

circular spline

14

actuator housing

15

thread

16

output bell

17

output shaft

18

roller bearing

19

system to be driven

20

drive shaft

21

mounting screw

22

Head

23

speed sensor

24

first seal

25

second seal

26

partition wall

27

diameter thickening

28

collar

29

threaded hole

30

housing seal

31

constriction

32

sensor

33

Sensor housing 32

34

encoder element

35

detector element

36

combustion engine

37

adjusting shaft

38

control device

39

mounting channel

40

washer

41

sleeve

42

first seal

43

second seal

44

entrance opening

45

Lid

46

clamping component

47

first sealed bearing

48

second sealed bearing

Claims (23)

Actuator (1), which has a drive motor (2), a gear (5) downstream of the drive motor (2) and a driven element (6), characterized by a fastening screw (21) for fastening the driven element (6) to a Drive shaft (20) to be driven by the actuator (1) of a system to be driven without dismantling the actuator (1) or dismantling parts of the actuator (1), the fastening screw (21) being designed and arranged in such a way that it cannot be removed, when the actuator (1) is not coupled to a system to be driven, without dismantling or destroying parts of the actuator (1) for this purpose. actuator (1) after claim 1 , characterized in that a. the gear (5) is arranged coaxially to the drive motor (2), and/or that b. the fastening screw (21) is arranged coaxially to the drive motor (2) and/or to the transmission (5), and/or that c. the fastening screw (21) has a collar (28) which limits the axial mobility of the fastening screw (21), and/or that d. the fastening screw (21) has a collar (28) which limits the axial mobility of the fastening screw (21), the collar (28) contacting the drive motor (2) when the fastening screw (21) running through a hollow shaft is displaced a constriction of the hollow shaft - and when shifted in the opposite direction it strikes the output element (6). actuator (1) after claim 1 or 2 , characterized in that the entire actuator (1) can be coupled as a fully assembled and functional structural unit to a system which is to be driven by the actuator (1) and which has a drive shaft (20), with a torsionally rigid connection of the output element (6) to the Drive shaft (20) can be produced without having to dismantle parts of the actuator (1). Actuator (1) according to one of Claims 1 until 3 , characterized in that a. the fastening screw (21) runs both through the gearbox (5) and through the drive motor (2), and/or that b. the head (22) of the fastening screw (21) and the driven element (6) are arranged on opposite sides of the actuator (1). Actuator (1) according to one of Claims 1 until 4 , characterized in that a. the actuator (1) has a fastening channel (39) through which the fastening screw (21) can be guided and/or through which a tool for rotating the fastening screw (21) can be guided, and/or that b. the actuator (1) has a fastening channel (39) which is delimited by a sleeve (41), and/or that c. the actuator (1) has a fastening channel (39) which is delimited by a circular-cylindrical sleeve (41), and/or that d. the actuator (1) has a fastening channel (39) which is delimited by a sleeve (41) which is stationary relative to the actuator housing (14) or stationary relative to the driven element (6), and/or that e. the actuator (1) has a fastening channel (39) which is delimited radially by a sleeve (41) aligned coaxially with the gear (5) and/or coaxially with the drive motor (2), and/or that f. the actuator (1) has a fastening channel (39) which runs both through the transmission (5) and through the drive motor (2), and/or that g. the actuator (1) has a fastening channel (39), the input opening and the output element (6) of which are arranged on opposite sides of the actuator (1). Actuator (1) according to one of Claims 1 until 5 , characterized in that a. the fastening screw (21) is designed and arranged to be non-rotatably connected to the driven element (6) in the installed state of the actuator (1) on a system to be driven, and/or that b. the fastening screw (21) is designed and arranged to be screwed into a drive shaft (20) to be driven, and/or that c. the fastening screw (21) is designed and arranged to be screwed into a drive shaft (20) to be driven, and/or that d. the fastening screw (21) has a collar (28) spaced axially from the head (22) which is designed and arranged to press the driven element (6) onto the drive shaft (20) to be driven, and/or that e. the fastening screw (21) has a collar (28) which is spaced axially from the head (22) and is designed and arranged to press the output element (6) against the end face of the drive shaft (20) to be driven. Actuator (1) according to one of Claims 1 until 6 , characterized in that the fastening screw (21) in the unmounted state of the actuator (1) protrudes from an actuator housing (14) of the actuator (1) and/or in the mounted state of the actuator (1) on a system to be driven flush with the actuator housing ( 14) concludes. Actuator (1) according to one of Claims 1 until 7 , characterized in that a. the fastening screw (21) is designed for coupling a sensor (32) which measures the rotational position and/or the number of revolutions of the fastening screw (21) relative to an actuator housing (14) or relative to a component of the actuator (1) fixed to the actuator housing, or that b. the head (22) of the fastening screw (21) is designed for coupling a sensor (32) which determines the rotational position and/or the number of revolutions of the fastening screw (21) relative to an actuator housing (14) or relative to a component of the actuator fixed to the actuator housing (1) measures. Actuator (1) according to one of Claims 1 until 8th , characterized in that a. the actuator (1) has two spaces that are sealed relative to one another, and/or that b. the actuator (1) seals two relative to one another tete rooms, wherein the transmission (5) is arranged in one of the rooms and the drive motor (2) or at least parts of the drive motor (2) or a speed sensor are arranged in the other of the rooms, and/or that c. the actuator (1) has two chambers which are sealed relative to one another, one of the chambers being designed and arranged to be connected to an oil lubrication system, and/or that d. the actuator (1) has two spaces that are sealed relative to one another, one of the spaces being designed and arranged to be connected to an oil lubrication system of the system to be driven, and/or that e. the actuator (1) has two relatively sealed spaces, one of which is filled with oil and the other with a gas, and/or that f. the actuator (1) has two relatively sealed spaces, one of the spaces with oil and the other is filled with air. actuator (1) after claim 9 , characterized in that the spaces are sealed relative to each other by means of at least one seal (42, 43), which can be used as a non-abrasive seal and/or as a dynamic seal and/or as a rotary seal and/or as a gap seal and/or as a seal that Seal uses a centrifugal effect, and / or is designed as a labyrinth seal. actuator (1) after claim 9 or 10 , characterized in that a. the seal (42, 43) rests against the fastening screw (21) and/or interacts with the fastening screw (21), and/or that b. the seal (42, 43) rests against the inside of a hollow shaft and/or interacts with a hollow shaft, and/or that c. the seal (42, 43) rests on the inside of a hollow shaft and/or interacts with a hollow shaft which is a drive shaft (20) of the gear (5) and/or an output shaft of the drive motor (2) or which is non-rotatably connected to a drive shaft ( 20) of the transmission (5) or an output shaft of the drive motor (2), and/or that d. the seal (42, 43) rests on the inside of a hollow shaft and/or interacts with a hollow shaft which is non-rotatably connected to a shaft generator of the transmission (5) designed as a voltage wave transmission, and/or that e. the seal (42, 43) rests against a sleeve (41) and/or that f. the seal (42, 43) rests against a coaxially aligned sleeve (41) and/or that g. the seal (42, 43) interacts with a sleeve (41) which surrounds a fastening channel (39) through which a fastening screw (21) for fastening the driven element (6) to a drive shaft (20 ) can be guided and through which a tool for rotating the fastening screw (21) can be guided. Actuator (1) according to one of Claims 1 until 11 , characterized in that a. a housing seal (30) is present, which on the one hand rests on an actuator housing (14) of the actuator (1) and/or interacts with an actuator housing (14) of the actuator (1) and on the other hand rests on the fastening screw (21) and/ or interacts with the fastening screw (21), and/or that b. a housing seal (30) is present, which on the one hand bears against an actuator housing (14) of the actuator (1) and/or interacts with an actuator housing (14) of the actuator (1), and on the other hand on the head (22) of the fastening screw ( 21) rests against and/or interacts with the head (22) of the fastening screw (21), and/or that c. the actuator (1) has two chambers sealed relative to one another, one of the chambers being filled with oil and the other with a gas, there being a housing seal which seals the gas-filled chamber from the chamber surrounding the actuator (1). Actuator (1) according to one of Claims 1 until 12 , characterized in that a. the fastening screw (21) provides at least one sealing surface, and/or that b. the fastening screw (21) provides at least one sealing surface which is in contact with a seal or a housing seal, and/or that c. the fastening screw (21) provides at least one sealing surface and has a thickened diameter in the area of the sealing surface, and/or that d. the fastening screw (21) provides at least one sealing surface and has a diameter in the area of the sealing surface which is greater than or equal to the diameter of the head (22) of the fastening screw (21). Actuator (1) according to one of Claims 1 until 13 , characterized in that the gear (5) is designed as a tension shaft gear and / or that the gear (5) is designed as a ring gear and / or that the output element (6) has an internally toothed ring gear. Actuator (1) according to one of Claims 1 until 14 , characterized in that a. an output component of the drive motor (2) and a drive component of the transmission (5) as separately herge provided components are formed, which are rotatably connected to each other, or that b. an output component of the drive motor (2) and a drive component of the transmission (5) are designed as separately manufactured components which are connected to one another in a torque-proof manner by means of at least one clamping component (46), or that c. an output component of the drive motor (2) and a drive component of the transmission (5) are designed as separately manufactured components which are connected to one another in a torque-proof manner by means of at least one clamping component (46) which is designed as a corrugated and/or elastic and/or cylindrically curved band and/or or as an elastic and/or cylindrically bent sheet metal strip and/or as a slotted ring. Actuator system with an actuator (1) according to one of Claims 1 until 15 and with a sensor (32) which measures the rotational position and/or the number of revolutions of the fastening screw (21) relative to an actuator housing (14) or relative to a component of the actuator (1) fixed to the actuator housing. drive system with a. an internal combustion engine and having an actuator (1) coupled to the internal combustion engine according to one of Claims 1 until 15 for changing the expansion stroke and/or the compression ratio of the internal combustion engine, or with b. an internal combustion engine and having an actuator system coupled to the internal combustion engine Claim 16 for changing the expansion stroke and/or the compression ratio of the internal combustion engine. drive system Claim 17 , characterized in that the internal combustion engine has an adjusting shaft (37), the expansion stroke and/or the compression ratio of the internal combustion engine being able to be changed by changing the rotational position of the adjusting shaft (37), and the output element (6) being non-rotatably connected to the adjusting shaft (37). and/or is arranged coaxially to the adjusting shaft (37). drive system Claim 18 , characterized in that a. the internal combustion engine has no sensor (32) for measuring the rotational position of the adjusting shaft (37), and/or that b. a control device determines the current setting of the expansion stroke and/or the compression ratio of the internal combustion engine exclusively by means of the sensor (32) coupled to the fastening screw (21). Propulsion system according to one of claims 17 until 19 , characterized in that the actuator (1) has two sealed spaces relative to each other, one of the spaces being connected to the oil supply system of the internal combustion engine. Motor vehicle including an actuator (1) according to one of Claims 1 until 15 and/or with an actuator system Claim 16 and/or with a drive system according to one of claims 17 until 20 . Use of an actuator (1) according to one of Claims 1 until 15 or an actuator system Claim 16 for changing the expansion stroke and/or the compression ratio of an internal combustion engine. Fastening screw (21) for an actuator (1) according to one of Claims 1 until 15 or for an actuator system Claim 16 , a. which has a collar (28) which is spaced axially from the head (22) and is designed and arranged to press the driven element (6) against the drive shaft (20) to be driven, and/or b. which has a collar (28) which is spaced axially from the head (22) and is designed and arranged to press the output element (6) against the end face of the drive shaft (20) to be driven, and/or c. the head (22) of which is designed for coupling a sensor (32) which measures the rotational position and/or the number of revolutions of the fastening screw (21) relative to an actuator housing (14) or relative to a component of the actuator (1) fixed to the actuator housing, and/or d. which is designed for coupling a sensor (32) which measures the rotational position and/or the number of revolutions of the fastening screw (21) relative to an actuator housing (14) or relative to a component of the actuator (1) fixed to the actuator housing, and/or e . which provides at least one sealing surface, and/or f. which provides at least one sealing surface and has a thickened diameter in the area of the sealing surface and/or g. which provides at least one sealing surface and has a diameter in the region of the sealing surface that is greater than or equal to the diameter of the head (22) of the fastening screw (21).

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