Actuating device for an internal combustion engine

Abstract

Actuating device for an internal combustion engine, comprising a housing in which an electric motor is arranged, which drives an output shaft (9) coupled to an actuating element (10) via a gear unit (7) and in which a circuit board (21) for receiving electronic circuit components (22) is arranged, wherein in the housing (1, 2) a space (19) is arranged at the opposite end (12) to the actuating element (10) and closed by a cover (24) for receiving and fastening the circuit board (21), which is separated from the gear unit (7) and the electric motor (4) by a wall (20), wherein a blind hole (14) is formed in the wall (20), in which the end (12) of the output shaft (9) opposite to the actuator (10) is mounted, wherein the circuit board (21) has standardized electrical connection contact holes (27) for connection to contact tongues (28) of a lead frame (30) for electrical contacting, wherein a different number of circuit modules (22) can be selected with the same number and arrangement of the connection contact holes (27), and wherein a diametrically magnetized circular or ring magnet (18) is arranged at the end (12) of the output shaft (9) opposite the actuator (10), which is in functional connection to a contactless sensor (23) arranged on the circuit board (21) for angular position detection, or two pin magnets are arranged on a circular line spaced from one another at the end of the output gear (8) axially opposite the actuator (10), which are in functional connection to a contactless sensor (23) arranged on the circuit board (21) for angular position detection.

Description

[0001] The invention relates to an actuating device for an internal combustion engine with a housing in which an electric motor is arranged, which drives an output shaft coupled to an actuating element via a gear unit and in which a circuit board for receiving electronic circuit components is arranged, wherein in the housing a space is formed, arranged at the opposite end to the actuating element, closed by a cover, for receiving and fastening the circuit board, which is separated from the gear unit and the electric motor by a wall.

[0002] Such adjusting devices are used in internal combustion engines, for example, to adjust switching flaps, throttle valves, exhaust flaps or charge movement flaps and are described in a large number of applications.

[0003] DE 103 21 653 B3 discloses an actuating device in which an electric motor is arranged in the housing. The motor has a drive shaft on which a worm is arranged, which meshes with a worm gear. The worm gear is arranged on an output shaft of the actuating device and has two receptacles for two magnets, which correspond to a non-contact sensor. The non-contact sensor is arranged on a circuit board, which is also located inside the housing. Contact with the circuit board is established via cables laid inside the housing.

[0004] Furthermore, EP 1 028 239 B1 discloses an actuating device for a throttle valve in which a segment of a ring magnet communicates with a contactless sensor, the sensor and circuit board also being arranged in the gear compartment.

[0005] DE 101 25 581 C2 discloses an actuating device with gear and electronics compartments separated from each other by various housing sections. The angular position is detected on the drive shaft of the worm gear via openings in the partition.

[0006] A disadvantage of such designs is the proximity of the circuit board, and thus the circuit components, to the electric motor and transmission, which can lead to heat and contamination problems. Furthermore, if customer requirements change regarding performance, gear ratio, or the design of the electronics unit, a complete redesign is necessary, as the space for the sensors and circuit board must be completely reconfigured.

[0007] From DE 197 46 518 A1 and DE 198 51 455 A1 it is generally known to attach a circuit board in a housing via plug contacts.

[0008] Therefore, the object of the invention is to create an actuator for an internal combustion engine that can be adapted to various customer requirements with as little effort as possible. Furthermore, heat transfer from the engine to the circuit board should be avoided as much as possible, and contamination of the circuit board should be prevented.

[0009] This object is achieved in that a blind hole is formed in the wall in which the end of the output shaft opposite the actuator is mounted, wherein the circuit board has standardized electrical connection contact holes for connection to contact tongues of a lead frame for electrical contacting, and wherein a different number of circuit components can be selected with the same number and arrangement of the connection contact holes, and wherein a diametrically magnetized circular or ring magnet is arranged at the end of the output shaft opposite the actuator, which is in functional connection to a contactless sensor arranged on the circuit board for angular position detection, or two pin magnets are arranged on a circular line spaced from one another at the end of the output gear axially opposite the actuator,which are functionally connected to a contactless sensor for angular position detection arranged on the circuit board. This creates a decoupling of the electronics unit from the heat-emitting electric motor and simultaneously determines the position and arrangement of a circuit board independently of its equipment in the housing. This makes it possible to implement both a simply constructed time-controlled or electronic-free actuator and an intelligent actuator with integrated electronic position control, with an otherwise identical actuator structure. Furthermore, the arrangement of the circuit board in a separate compartment protects it from contamination. By arranging the diametrically magnetized circular or ring magnet at the end of the output shaft opposite the actuator, which is functionally connected to a contactless sensor for angular position detection arranged on the circuit board,Reliable position feedback is ensured, operating in a contactless manner and completely separated from the engine and transmission compartment. Adjustments to the position of the magnet relative to the sensor are also unnecessary when changing the desired setting angle or design. In the alternative design with two pin magnets on a circular line, a simple actuator is created without changing the rest of the actuator, with the magnets serving to detect the end positions.

[0010] Preferably, the electrical contact between the circuit board, an external connector, and the electric motor is made via the lead frame molded into the housing. The lead frames can then be inserted into the injection mold and overmolded, ensuring a tight fit in the housing and eliminating the need for an additional assembly step. This also makes it easy to adapt the electrical contact to different housings by modifying the lead frame design. Furthermore, it is also possible to use the same lead frame and only differently equipped circuit boards for different applications.

[0011] In a further embodiment, the circuit board is secured via the terminal holes using insulation displacement contact to the contact tabs of the overmolded leadframe protruding from the housing, and the electrical contact is established. Using this type of insulation displacement contact eliminates the need for additional fastening of the circuit board, for example, with screws. This ensures both mechanical and electrical connection in a single manufacturing step.

[0012] In a further embodiment, an output gear of the transmission unit is formed integrally with the output shaft, with the end of the output shaft opposite the actuator being designed as a hollow shaft, on the inner wall of which an axially extending projection is formed, which corresponds to a groove formed on the ring magnet. In this way, the position of the magnet relative to the output shaft can be easily determined during assembly or production, so that the optimal alignment of the magnet at the end points can be ensured for a defined maximum setting angle. This leads to the most linear resolution possible of the voltage generated in the sensor and thus to more precise angle data.

[0013] In a further preferred embodiment, the electric motor has contact tongues for electrical contact, and fork contacts are formed at two first ends of the stamped grid. These fork contacts are molded into the housing with the stamped grid. The contact tongues are each pressed into a gap of one of the fork contacts, creating a spring preload between the fork contacts and the contact tongues. This again ensures simple electrical contact, in this case between the electric motor and the stamped grid. A sufficiently strong connection is achieved both mechanically and electrically in a single assembly step, without the need for welding, soldering, or screwing.

[0014] In a further development, two contact tabs of the stamped grid, which serve as ground contacts, protrude from the housing toward a pole tube of the electric motor. After the electric motor is inserted into the housing, they are elastically deformed and rest against the pole tube. This creates a vibration-resistant ground connection through the elastic deformation of the contact tabs. This also eliminates additional assembly steps.

[0015] Furthermore, it is advantageous if the housing shape can be modified using various interchangeable inserts in the mold for injection molding the housing. This allows the gear ratio of the gear unit to be freely selected depending on the application by adjusting the number of teeth on a gear or the diameter of a worm, as well as the power and design of the electric motor. Since the board size and contacting, as well as the existing leadframe, are fixed, and thus only the contact points of the gear components used and the electric motor are changed, the housing can be easily adapted to these components without the need for additional redesigns regarding electrical contacting or control.

[0016] In a further design, different connector shapes and different numbers of pins can be selected according to the existing contact to the circuit board and the electric motor by using different interchangeable inserts in the tool for injection molding the housing and adapting the lead frame shape. Since the lead frames vary depending on the application and the required number of pins depending on the selected actuator intelligence, but the contact points are largely fixed, the connector shape can also be changed during one-piece production with the housing in the same operation by changing the interchangeable insert of the injection molding tool to meet different requirements, without having to make additional design changes regarding the relative position of the components. This also allows the manufacturing and assembly process to be retained.

[0017] The result is a modular actuator assembly that allows different customer requirements to be met with minimal effort on an existing production line without changing the assembly or production sequence. Only the adaptation of the corresponding interchangeable inserts of the tool for molding the housing or lead frame is required. The actuator assembly is also very easy to manufacture, requiring only a few assembly steps. This also prevents thermal contact between the electric motor and the electronics unit, as well as contamination of the circuit board by the actuator assembly's driving parts.

[0018] An embodiment is shown in the figures and is described below. Fig. 1 shows an exploded view of an actuating device according to the invention with position feedback in three-dimensional representation. Fig. 2 shows a housing part with electrical contact in three-dimensional representation. Fig. 3 shows a comparison of different equipment variants of a circuit board of the device according to the invention. Fig. 4 shows an example of a lead frame of the adjusting device according to the invention in three-dimensional representation.

[0019] The Fig. The actuating device according to the invention shown in Figure 1 consists of a two-part housing with an upper housing part 1 and a lower housing part 2, which are connected to each other in the assembled state via a clip connection 3. Additionally, the housing parts 1, 2 are glued together to ensure a tight connection. An electric motor 4 is arranged inside the housing 1, 2, via which a drive shaft 5 is driven in a known manner. A worm 6 is arranged on the drive shaft 5 between two thrust washers 41, which is mounted in corresponding receptacles in the housing 1, 2.

[0020] The worm 6 is part of a gear unit 7, which, in addition to the worm 6 in the present embodiment, includes an output gear 8 designed as a worm wheel. This is formed integrally with an output shaft 9, which extends through the output gear 8 on both sides and is mounted at an end 11 facing an actuator 10 in a cylindrical opening 13 and at an end 12 of the output shaft 9 opposite the actuator 10 in a corresponding cylindrical blind hole 14.

[0021] The opening 13 is formed in the upper housing part 1, into which the end 11 of the output shaft 9 projects. This end 11 of the shaft 9 is designed as a hollow shaft, with the inner walls being shaped such that they correspond to a coupling member 15, which is inserted from the outside into the end 11 of the output shaft 9, thereby creating an at least rotationally fixed connection. A sealing ring 16 is placed around the opening 13 from the outside of the housing. This sealing ring is fastened to the housing 1, 2 by mounting the coupling member 15 on the output shaft 9 and seals the interior of the housing 1, 2 from the outside. Connected to the coupling member 15 is the actuator 10, which in the present embodiment is designed as a metal lever for adjusting, for example, a flap.

[0022] The opposite end 12 of the output shaft 9 is also designed as a hollow shaft in the present embodiment, with an axially extending projection (not shown) formed on an inner wall of the hollow shaft, which corresponds to a groove 17 formed in a diametrically magnetized circular magnet 18, so that the position of the circular magnet 18 relative to the gear 8 is determined upon assembly. This simultaneously also determines the optimal position of the magnet relative to the actuator 10, so that with a limited adjustment angle, a largely linear range can be used for angular position detection.

[0023] As already described above, the end 12 of the shaft 9 with the circular magnet 18 is mounted in the cylindrical blind hole 14. The end of the shaft 9 extends toward a space 19, which is completely separated by a wall 20 from the space in which the electric motor 4 or the gear unit 7 are arranged.

[0024] Arranged inside the chamber 19 is a circuit board 21, which carries various circuit components 22, in the present embodiment in particular a contactless sensor 23. This corresponds to the diametrically magnetized circular magnet 18, which, after assembly, is arranged in a defined position exactly above the sensor 23. The movement of the magnet 18 with the actuator 10 or the output gear 8 induces a voltage in the contactless sensor 23 in a known manner, which serves as a measure for calculating a rotation angle by an external or internal control unit arranged on the circuit board 21.

[0025] The wall 20 between the circuit board 21 and the electric motor 4 or the gear unit 7 creates both a thermal decoupling of the chamber 19 and a significantly improved resistance of the circuit board 21 or the circuit components 22 to contamination. The chamber 19 is closed by a cover 24, on the side walls of which a groove 25 is formed, into which the side walls 26 delimiting the chamber 19 engage, thereby determining the position of the cover 24. The chamber 19 is tightly closed by the cover 24 via a simple adhesive connection.

[0026] In such an embodiment, it is possible to mount the circuit board 21, as best shown in Fig. 3, it can be implemented with different circuit components 22, thus either implementing the position control entirely within the actuator or simply measuring a voltage from sensor 23 and forwarding the data to an external electronic position control system. Pure time control or the direct, electronic-free transmission of the current via the ECU without a sensor or magnet would also be conceivable.

[0027] The circuit board 21 is secured both electrically and mechanically in the space 19 via an insulation displacement contact. For this purpose, the circuit board has standardized connection contact holes 27, which are always arranged at the same positions on the circuit board 21, regardless of the design of the actuator. When the circuit board 21 is pressed onto contact tabs 28, these contact tabs 28, which have a through hole in the upper area, are Fig. 4, is pressed together in this area. After the circuit board 21 is pressed onto the contact tongues 28, these expand again in their upper area, so that the resulting spring preload ensures a firm fit of the circuit board 21. In addition, in the embodiment shown in Fig. 2 that support surfaces 29 are formed on the wall 20, which prevent the circuit board 21 from being moved too far onto the contact tongues 28.

[0028] The contact tongues 28 are parts of a stamped grid 30, which is Fig. 4. A first side 31 of the stamped grid 30 leads from the circuit board 21 to a connector 31, which is formed integrally with the lower housing part 2. By appropriately shaping the side 32 of the stamped grid 30 in the outwardly leading connector area, various connector shapes can be realized by adapting the stamped grid 30 and the housing 1, 2. Advantageously, the contact tongues 28, which lead to the connector 31, are arranged in the immediate vicinity of the connector 31, so that the length of the lines of the stamped grid 30 is minimized.

[0029] The entire lead frame 30 is injected into the housing part 2 during the manufacture of the housing part 2. The contact tabs 28 arranged on the opposite side 33 of the circuit board 31, which engage in the connection contact holes 27 of the circuit board 21, serve for motor contact and motor power supply.

[0030] Two ends of the lead frame 30 projecting into the housing 1, 2 are designed as fork contacts 34, via which electrical contact is established with contact tongues 35 of the electric motor 4. These fork contacts 34 are also overmolded in the lower area, thus achieving high stability when inserting the contact tongues 35 of the motor 4. Accordingly, additional welding or soldering connections for contacting the electric motor 4 are not necessary.

[0031] Furthermore, the lead frame has two contact tongues 36 for grounding the electric motor 4, which also protrude from the plastic of the housing part 2 and are elastically deformed when the motor 4 is inserted and rest against a pole tube 37 of the electric motor 4. This elastic deformation ensures vibration-resistant grounding. Furthermore, Fig.4 that in the area of ​​the stamped grid 30 and connected to it, interference suppression chokes 38 are arranged, which are also injected into the housing part 2.

[0032] It should be clear that with such a defined arrangement and contacting of the circuit board 21 to the output shaft 9, modification and adaptation to different customer requirements are possible simply by changing the interchangeable inserts of the injection molding tool for producing the housing 1, 2 and the lead frame. In this case, only the shape of the housing 1, 2 needs to be adapted to the motor 4 or the gear unit 7 used. The same applies to the design of the connector 31. This means that the same production line can always be used. Both thermal decoupling between the circuit board and the electric motor and reliable contacting are maintained while maintaining the same basic design.

Claims

[1] Actuating device for an internal combustion engine, with a housing in which an electric motor is arranged, which drives an output shaft (9) coupled to an actuating element (10) via a gear unit (7) and in which a circuit board (21) for receiving electronic circuit components (22) is arranged, wherein in the housing (1, 2) a space (19) is arranged at the opposite end (12) to the actuating element (10) and closed by a cover (24) for receiving and fastening the circuit board (21), which is separated from the gear unit (7) and the electric motor (4) by a wall (20), wherein a blind hole (14) is formed in the wall (20), in which the end (12) of the output shaft (9) opposite to the actuator (10) is mounted, wherein the circuit board (21) has standardized electrical connection contact holes (27) for connection to contact tongues (28) of a lead frame (30) for electrical contacting, wherein a different number of circuit modules (22) can be selected with the same number and arrangement of the connection contact holes (27), and wherein a diametrically magnetized circular or ring magnet (18) is arranged at the end (12) of the output shaft (9) opposite the actuator (10), which is in functional connection with a contactless sensor (23) arranged on the circuit board (21) for angular position detection, or two pin magnets are arranged on a circular line spaced from one another at the end of the output gear (8) axially opposite the actuator (10), which are in functional connection with a contactless sensor (23) arranged on the circuit board (21) for angular position detection. [2] Actuating device for an internal combustion engine according to claim 1, characterized by that the electrical contact between the circuit board (21), an outwardly leading plug (31) and the electric motor (4) is made via the punched grid (30) injected into the housing (1, 2). [3] Actuating device for an internal combustion engine according to claim 2, characterized by that the circuit board (21) is fastened via the connection contact holes (27) on the contact tongues (28) of the overmolded lead frame projecting from the housing (1, 2) and the electrical contact is made. [4] Actuating device for an internal combustion engine according to one of the preceding claims, characterized bythat an output gear (8) of the gear unit (7) is formed integrally with the output shaft (9), wherein the end (12) of the output shaft (9) opposite the actuator (10) is designed as a hollow shaft, on the inner wall of which an axially extending projection is formed, which corresponds to a groove (17) formed on the circular magnet (18). [5] Actuating device for an internal combustion engine according to one of the preceding claims, characterized by that the electric motor (4) has contact tongues (35) for electrical contacting, and fork contacts (34) are formed at two first ends of the stamped grid (30), which fork contacts are injected into the housing with the stamped grid (30), wherein the contact tongues (35) are each pressed into a gap of the fork contacts (34), whereby a spring preload is created between the fork contacts (34) and the contact tongues (35). [6] Actuating device for an internal combustion engine according to one of the preceding claims, characterized by that two contact tongues (36) of the stamped grid (30), which serve as a ground contact, protrude from the housing in the direction of a pole tube (37) of the electric motor (4) and, after the electric motor (4) has been inserted into the housing (1, 2), rest against the pole tube (37) in an elastically deformed manner.

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