DE102008006199A1 - Actuating drive i.e. phase adjuster, for e.g. adjusting element at camshaft of internal combustion engine, has power transformer with primary coil and secondary coil, whose number of turns is greater than number of turns of primary coil - Google Patents

Abstract

The drive has a transverse flux motor (1) rotatable with a machine element for driving an adjusting element, where the motor includes a rotor (3) and a stator (4). An inductive power transformer (22) includes a primary coil (23) at a machine frame and a secondary coil (24) at the motor. The primary coil and the secondary coil are arranged opposite to each other. A number of turns of the secondary coil is greater than a number of turns of the primary coil. The adjusting element is driven via a planetary gear (2) by the motor, and the primary coil is connected to a voltage regulator.

Description

The The present invention relates to an actuator for a Adjustment element on one opposite a machine frame rotating machine element. Such actuators are used for example in Shape of a phase adjuster for adjusting the relative angular position a camshaft relative to a crankshaft of an internal combustion engine used.

From the DE 41 10 195 A1 an adjusting device for a camshaft is known, which allows a relative displacement between a camshaft and a driving drive wheel of an internal combustion engine driving them. For this purpose, an electric motor is provided which causes a relative adjustment via a control gear. The stator of the electric motor is arranged stationarily in the housing and the adjusting gear is mounted together with the rotor on a shaft piece relatively rotatable to the camshaft, wherein the shaft piece is rotatably connected as part of the inner part with the cam end piece. If the electric motor is subjected to a voltage, then a brief fast or slow running of the co-rotating adjusting gear is achieved, so that a relative displacement of the camshaft relative to the drive wheel takes place. The disadvantage of this solution is that the power of the electric motor must be significantly higher than the usable power for relative adjustment, since the torque must be transmitted to adjust with an increased speed to the system speed. Another disadvantage is due to the fact that the control gear must be self-locking, so that additional forces to hold the transmission are not required. For this purpose, the actuating gear is designed with a low mechanical efficiency of, for example, less than 40%, whereby the power of the electric motor is interpreted to be increased again. Consequently, the power supply for the electric motor is loaded to a high degree, whereby the cost of the electronics for driving the electric motor are high.

From the EP 0 903 471 A1 a device for adjusting the camshaft of an internal combustion engine is known which has an adjusting mechanism which is actuated by a fixedly connected to the camshaft or the drive wheel electric motor. An adjustment is achieved in that the adjusting mechanism comprises a planetary gear. In order for the electric motor to rotate together with the drive wheel, slip rings are provided on the motor, which are fed by fixed sliding contacts. A disadvantage of this solution is the effort required to transmit the electrical energy and the control information to the rotating motor. The mechanical rotary transformer formed by the slip rings and sliding contacts requires a sealed space and endangers the long-term stability of the system as a wearing part.

Farther are known from the prior art solutions in which an inductive rotary transformer for transmission the electric energy is used on a rotating engine. These solutions require both on the primary as well as on the secondary side of the rotary transformer current-carrying electronic components, causing these Solutions are expensive.

The The object of the present invention is to provide an actuator, for example, for adjusting a camshaft of an internal combustion engine in which a secure and long-term stable transmission the electrical energy to the electric motor allows little effort is.

The The object is achieved by an actuator according to the attached claim 1.

Of the Actuator according to the invention is for adjusting an adjustment provided on a rotating machine element. This machine element can for example by a camshaft be formed, which rotates in an internal combustion engine. The rotation the machine element is opposite to a machine frame, for example a housing of the internal combustion engine. The adjusting element is powered by an electric motor. This engine is rotating together with the rotating machine element and has a rotor and a stator. It is in the stator accordingly around a rotating stator, as it faces the machine frame rotates. The actuator also includes an inductive power transformer for transmitting the electrical energy to drive the electric motor. The inductive power transformer includes a primary coil which is attached to the machine frame is. Furthermore, the inductive power transformer comprises a secondary coil which is arranged on the engine and thus together with the engine and the rotating machine element rotates. So that the electrical energy from the primary coil on the secondary coil can be transmitted are the Primary coil and the secondary coil opposite arranged to each other. According to the invention is a Number of turns of the secondary coil greater as a number of turns of the primary coil, so the transmission factor of the power transformer greater than 1 is.

A significant advantage of the actuator according to the invention is that in comparison to solutions according to the prior art, a reduced electrical power is to be transmitted. In the actuator, a non-self-locking hochef be used efficient gear, but still only small losses for holding certain positions arise. The power for holding a certain position corresponds to the self-losses of the actuator, as caused by the necessary to be applied by the co-rotating engine torques only inherent losses in windings in the circuit of the motor. This leads to a reduction of the maximum Stellleis device by a factor between 2 and 3 or more. For example, the output power of such a motor can be reduced from 300 W to 111 W when the required actuating power is 100 W.

The Primary coil is preferably electrically connected to a voltage regulator connected so that it supplies a constant voltage which, at the same time, results in a constant output voltage Secondary coil leads.

The Use of the inductive power transformer as boost converter, which is preferably fed by a regulated voltage leads to that, for example, up to 90% of the required chip area for power semiconductors over the solutions according to the prior art with a stationary Stator can be saved. Additionally reduced the total power requirement in the top by up to 80%, which means also the power semiconductors on the stationary side be made considerably smaller. Despite being by the additional energy conversion conditional higher Number of functional components is the total requirement of chip area in sum of all power semiconductors significantly smaller than in solutions with stationary stator.

By the use of the rotary transmission as a regulated boost converter, for example, the typical vehicle voltages in the amount of 6V to 28V to a constant voltage of 30 V (± 1 V), can be a constant supply voltage be ensured of the electric motor. Thus flows in the most unfavorable for the interpretation assumed case with, for example, 120 W driving power not a current of 20 A, but only a current in height of 4 A through the secondary electronics. The components can therefore be designed much smaller. Because the required dielectric strength does not increase, the chip area could be the same Efficiency quadratic decrease to the boost factor.

at a preferred embodiment of the invention Actuator this is designed to be one of outside to operate the actuator available Asked supply voltage is generally greater than the voltage to be applied to the primary coil. insofar this supply voltage can fluctuate is its minimum value greater than that to be applied to the primary coil Tension. The outside of the operation of the actuator Provided supply voltage is in the most cases a DC voltage. Otherwise it is preferably to rectify. The supply voltage applied as DC voltage or the rectified supply voltage is with an inverter (Chopper) in a to be applied to the primary coil AC voltage changed. Due to the voltage conditions described it only requires for the operation of the inverter an operation as buck converter, whereby the effort for the control electronics is reduced again. The inverter existing transistors are at a possible increase from the outside to the operation of the actuator available Asked supply voltage switched on shorter and shorter, that is, the duty cycle of the transistors is lowered. As a result, the voltage applied to the primary coil, high-frequency AC voltage smoothed by the inductance limited.

at a preferred embodiment of the invention Actuator is the adjusting element via a planetary gear driven by the engine. A sun gear of the planetary gear is rotatably attached to the rotor while the adjusting element by one or more planetary gears of the planetary gear is driven. A ring gear of the planetary gear is on the stator attached to the engine.

Of the Motor is preferably designed as a transverse flux motor, on the Stator the ring gear of the planetary gear is placed. An advantage the transverse flux motor is that he has a high torque and has a very low terminal resistance. By putting on of the ring gear of the planetary gear on the stator of the transverse flux motor Both the stator and the ring gear can be a functional unit form, which can be carried out space-saving.

The actuator according to the invention is particularly suitable as a phaser for adjusting the relative angular position of a camshaft relative to a crankshaft of an internal combustion engine. However, the actuator according to the invention is also suitable for many other applications, for example for adjusting the angular position of a crank of a crank CFT. A Crank (CFT) (continuously variable transmission) is a continuously variable transmission in which an adjustment is achieved by changing the angular position of a crank. Crank CFTs are often designed so that several cranks rotate in a gearbox housing and drive a common output. Another application for the actuator according to the invention is the adjustment of a clutch, such as a four-wheel drive clutch. Here, the actuator according to the invention is used to move an adjusting a rotating clutch disc, which rotates relative to other components of the clutch in a housing. In principle, the actuator according to the invention is suitable for different adjustment movements of the adjusting element, for example for rotary or translatory adjusting movements.

Further Advantages, details and developments of the present invention result from the following description of a preferred embodiment, with reference to the drawing.

The only 1 shows a preferred embodiment of the actuator according to the invention in a cross-sectional view. The actuator shown is particularly suitable for adjusting the phase position of a camshaft of an internal combustion engine relative to a driven by a crankshaft drive wheel. The actuator according to the invention comprises a transverse flux motor 01 and a planetary gear 02 , The transverse flux motor 01 has a rotor 03 and a stator 04 on. The stator 04 is through a housing 06 enclosed in which a ring gear 07 of the planetary gear 02 is used. For this purpose, the ring gear 07 a connection sleeve 08 on which in an inner circumference of the housing 06 of the stator 04 is inserted and an attachment to the stator 04 allows. The connection sleeve 08 the Hohlra of 07 is on a rolling bearing 09 which in turn is based on a wave 11 of the rotor 03 is attached. The rolling bearing 09 allows storage of the rotor 03 in the stator 04 , On the wave 11 of the rotor 03 is a sun wheel 12 of the planetary gear 02 attached. The sun wheel 12 is engaged with planetary gears 13 which, in turn, engage the ring gear 07 stand. The planet wheels 13 be through a planetary gear 14 stored and guided. The planetary wheel guide 14 has an output 16 of the planetary gear 02 on. The downforce 16 is like the rotor 03 of the transverse flux motor 01 around a rotation axis 17 rotatable.

If the actuator used as a phaser for a camshaft of an internal combustion engine, so for example, the output 16 rotatably connected to the camshaft. The planetary gear 02 is opposite the output 16 over the ring gear 07 to drive, for example, by a drive wheel (not shown) on the ring gear 07 is circumferentially mounted, which is driven by the crankshaft. As long as the rotor 03 in the transverse flux motor 01 does not rotate, the relative position of the sun gear changes 12 opposite the planet wheels 13 as well as with respect to the ring gear 07 Not. Consequently, the planetary gear remains 02 unchanged in its entirety, so that the position of the drive wheel with respect to the camshaft does not change. Thus, the phase angle of the crankshaft relative to the camshaft remains constant. Will the rotor 03 of the transverse flux motor 01 driven, so the sun wheel rotates 12 opposite the ring gear 07 , which at the same time the meshing planetary gears 13 rotate. Furthermore, this will cause a rotation of the planetary gear 14 opposite the ring gear 07 causes. Consequently, the rotational position of the drive wheel relative to the camshaft changes, so that a phase adjustment of the camshaft relative to the crankshaft is possible.

The rotor 03 of the transverse flux motor 01 has permanent magnets at its outer periphery 18 on. The permanent magnets 18 rotate between two conductor rings 19 , which in powder cores 21 in the stator 04 are introduced.

In the erfindungemäßen actuator rotate the stator 04 and the rotor 03 of the transverse flux motor 01 together with the rotating machine element, for example with a camshaft and its drive wheel. To the electrical energy to drive the transverse flux motor 01 from a non-rotating machine frame, for example a housing of an internal combustion engine, to the rotating transverse flux motor 01 to transmit, the actuator according to the invention has an inductive power transformer 22 on which a primary coil 23 and a secondary coil 24 includes. The primary coil 23 is in a primary nucleus 26 arranged. The secondary coil 24 is in a secondary core 27 arranged. The secondary coil 24 is in common with the secondary core 27 in a cylindrical recess in the stator 04 of the transverse flux motor 01 arranged and fastened there. Consequently, the secondary coil rotates 24 together with the stator 04 , The primary coil 23 is in common with the primary nucleus 26 attached to a machine frame (not shown). The inductive power transformer 22 is thus designed as a rotary transformer. The primary nucleus 26 with the primary coil 23 is within a cylindrical recess in the stator 04 arranged and is the secondary core 27 with the secondary coil 24 across from. Between the primary coil 23 and the secondary coil 24 is an air gap 28 formed, via which an inductive power transmission between the primary coil 23 and the secondary coil 24 he follows.

By the arrangement of the primary core 26 with the primary coil 23 in the cylindrical recess of the stator 04 form the inductive power transformer 22 and the transverse flux motor 01 a compact cylindrical unit. The primary coil 23 and the secondary coil 24 are designed such that the inductive power transformer 22 one Transmission factor greater than 1 and thus an increase in the voltage due to the inductive power transmission takes place. For example, the typical voltages in a car between 6 and 28 V can be transformed to a voltage of over 30 V. The transverse flux motor 01 has a secondary-side control electronics 29 on, on the outer circumference of the rotor 03 is attached and includes a rectifier and a motor drive. Furthermore, the transversal flux motor 01 a primary-side control electronics (not shown) having a voltage regulator for controlling the primary coil 23 applied voltage, resulting in a constant voltage at the secondary coil 24 is guaranteed. The rectifier and the motor control in the secondary-side control electronics 29 only work with the current reduced by the voltage step-up ratio. The voltage regulator in the primary-side control electronics may, for example, be a voltage regulator (preferably pure buck converter) for a voltage of 6 V ± 0.2 V. The through the inductive power transformer 22 voltage regulated up to a factor of 5 (6V to 30V) and regulated by the voltage regulator located in a chopper (not shown) will cause the required currents to decrease. For example, if 120 W driving power is required for the actuator, the maximum current through the control electronics is only 4 A, compared to a current of 20 A, which would be required if the minimum voltage of 6 V were not increased. As a result, in the secondary-side control electronics 29 used electronic components are designed to be much smaller. For the example mentioned, the resistance values of the electronic components can be higher by a factor which corresponds to the square of the ratio of the voltage boost without this leading to an increase in the losses in the electronic components. Is in the secondary-side control electronics 29 For example, a MOSFET used, its volume resistance must be only 0.25 Ω instead of 0.01 Ω. In the same ratio, the required chip area of power transistors can be reduced with increasing efficiency. With the size (capacity) of the power transistors, it is also possible to implement output stage drivers with a significantly smaller chip area. With the current, the size and cost of passive components (capacitors and inductors), which in the with the stator 04 rotating secondary control electronics 29 be used.

The electronic components of the secondary-side control electronics 29 , which includes, for example, a power amplifier and rectifier, are preferably integrated into a smart power module. In this way, a direct wiring can be carried out within an encapsulation of a multi-chip component, which largely the active part of the control electronics 29 represents, so no circuit carrier or similar components for the secondary-side control electronics 29 required are. For example, by using a smartpower device, the number of pits and thus the number of solder joints and the interconnects are reduced considerably, for example from 80 to 20.

The Smartpower module, including peripheral modules, is integrated into an MID component. An MID component (molded interconnected device) is a circuit carrier in which metallic interconnects are applied to an injection-molded plastic carrier. The use of an MID component makes it possible to dispense with additional circuit carriers, for example in the form of a circuit board. Furthermore, the required interconnects can be guided in three dimensions, so that contact plug to Transversalflussmotor 01 or also position sensors of the transverse flux motor 01 can be contacted directly.

Of the actuator according to the invention must in contrast to many solutions according to the state of Technique not carried out with a self-locking gear become. Consequently, the transmission ratio can be smaller to get voted. Therefore, with a smaller engine power even at low speeds high torques of the actuator causes.

The higher compared to the prior art efficiency of the transmission gear 02 allows a reduction in the through the inductive power transformer 22 to be transmitted power, which also causes the primary coil 23 can be designed for correspondingly lower currents and the load on the supply decreases. Consequently, in addition to active and passive components for driving the primary coil 23 be designed correspondingly smaller. Semiconductor of an H-bridge in front of the primary coil 23 are preferably also integrated into an electronic device.

By reduced compared to the prior art to be transmitted electrical power, the electronic components can be made smaller both on the primary and on the secondary side. In addition, the power transformer is power transformer 22 into the annular transverse flux motor transverse flux motor 01 integrated, so that the space requirement for the actuator according to the invention is low. In addition, the cost of a non-self-locking, low translated transmission transmission 02 significantly lowered.

01

transverse flux

02

planetary gear

03

rotor

04

stator

05

-

06

casing of the stator

07

ring gear

08

connecting sleeve of the ring gear

09

roller bearing

10

-

11

wave of the rotor

12

sun

13

planetary gears

14

Planetenradführung

15

-

16

output

17

axis of rotation

18

permanent magnets

19

conductor rings

20

-

21

powder cores

22

inductive Power Transformers

23

primary coil

24

secondary coil

25

-

26

primary core

27

secondary core

28

air gap

29

secondary side control electronics

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4110195 A1 [0002]
• EP 0903471 A1 [0003]

Claims (14)

Actuator for an adjusting element on a machine element rotating relative to a machine frame, comprising an electric motor rotating with the machine element (US Pat. 01 ) for driving the adjusting element, which has a rotor ( 03 ) and a stator ( 04 ) having; and an inductive power transformer ( 22 ), which is a primary coil ( 23 ) on the machine frame and a secondary coil ( 24 ) on the engine ( 01 ), wherein the primary coil ( 23 ) and the secondary coil ( 24 ) are arranged opposite one another, characterized in that a number of turns of the secondary coil ( 24 ) greater than one turn number of the primary coil ( 23 ). Actuator according to claim 1, characterized in that the adjusting element via a planetary gear ( 02 ) by the engine ( 01 ), and that the primary coil ( 23 ) is electrically connected to a voltage regulator. Actuator according to claim 2, characterized in that a sun gear ( 12 ) of the planetary gear ( 02 ) rotatably with the rotor ( 03 ) of the motor ( 01 ) is connected and that the adjusting element by a planetary gear ( 13 ) of the planetary gear ( 02 ) is driven. Actuator according to claim 3, characterized in that a ring gear ( 07 ) of the planetary gear ( 02 ) on the stator ( 04 ) of the motor ( 01 ) is attached. Actuator according to claim 4, characterized in that the motor by a transverse flux motor ( 01 ) is formed on the stator ( 04 ) the ring gear ( 07 ) is attached. Actuator according to one of claims 1 to 5, characterized in that the stator ( 04 ) has a cylindrical recess in which the primary coil ( 23 ) of the power transmitter ( 22 ) is arranged. Actuator according to one of claims 1 to 6, characterized in that the number of turns of the secondary coil ( 24 ) by a factor of 2 to 10 greater than the number of turns of the primary coil ( 23 ). Actuator according to claim 7, characterized in that the number of turns of the secondary coil ( 24 ) by a factor of 3 to 5 greater than the number of turns of the primary coil ( 23 ). Actuator according to one of claims 1 to 8, characterized in that a voltage rectifier and other electronic components for controlling the motor ( 01 ) are integrated in a smart power module. Actuator according to claim 9, characterized in that the smart power module including peripheral components in an MID component ( 29 ) is integrated. Actuator according to one of claims 1 to 10, characterized in that it is designed for a request from the outside to the operation of the actuator for use Ver supply voltage which is greater than that at the primary coil ( 23 ) is to be applied voltage. Actuator according to one of claims 1 to 11, characterized in that it provides for the adjustment on a camshaft forming the rotating machine element Internal combustion engine is executed. Actuator according to one of claims 1 to 11, characterized in that it provides an adjusting element on a crank forming the rotating machine element Crank-CFT is executed. Actuator according to one of claims 1 to 11, characterized in that it provides an adjusting element on a clutch disc forming the rotating machine element a coupling is executed.