DE102008053573B4 - Actuator for operating a linear unit - Google Patents

Abstract

Actuating drive (1) for actuating a linear unit, in particular an exhaust gas recirculation valve, with an electric motor (2), a reduction gear which has a rack and pinion gear (5) with a pinion (25) and a rack (26), a gear housing (6) and a housing-fixed sensor (29) for detecting a movement state of the actuator, a sensor transmitter (30) being fastened to the toothed rack (26) and being arranged between the toothed rack (26) and the gear housing (6), characterized in that the sensor (29) is arranged on a circuit board (28) which is accommodated in a pocket (38) of the gearbox housing, that the circuit board (28) has contact pins (35) which are in contact with sensor connections (34) in the gearbox housing (6), that the Sensor connections (34) with baffles (36) are in one piece, which are an integral part of the gear housing (6), that the pocket (38) in a support (27) serving as a housing projection of the gear housing s (6) so that part of the guide plates (36) are led to a plug housing (31) that is one piece with the gear housing, and plug contacts (32) form there for a connector plug, that further plug contacts (32) from the plug housing (31) are led to a brush bridge (44) and are in one piece with brush connections (33), these baffles (36) also being an integral part of the gear housing (6), that baffles (36) are led from the connector housing (31) to the brush bridge (44). and further guide plates (36) are routed from the connector housing (31) to the printed circuit board (28), the guide plates being an integral part of the gear housing (6), that the brush bridge (44) is held between the motor housing (43) and the gear housing (6), serves as an end shield and are equipped with chokes whose connections are contacted by the brush connections 33.

Description

The invention relates to an actuator (1) for actuating a linearly movable exhaust gas recirculation valve, with an electric motor (2) and a reduction gear, which has a rack and pinion gear (5) with a pinion (25) and a rack (26), a gear housing (6) and has a housing-fixed sensor (29) for detecting a movement state of the actuator, a sensor transmitter (30) being fastened to the toothed rack (26) and being arranged between the toothed rack (26) and the gear housing (6).

From the DE 101 12 033 A1 a generic actuator is known in which a sensor is arranged unprotected in the transmission housing.

The object of the invention is to protect the sensor against electrostatic discharges during assembly and on the fully assembled unit. Furthermore, the wiring and assembly effort for making the electrical connections should be reduced and the number of parts should be minimized.

According to the invention, this object is achieved in that the sensor (29) is arranged on a circuit board (28) which is accommodated in a pocket (38) of the transmission housing, that the circuit board (28) has contact pins (35) which are connected to sensor connections ( 34) in the gearbox housing (6) are in contact and the sensor connections (34) are in one piece with baffles (36) which are an integral part of the gearbox housing (6). By accommodating the sensor in a pocket (38) inside the gear housing (6), there is always a vibration-proof and precise positional assignment to the sensor transmitter (30) on the toothed rack (26). The wiring and assembly work is reduced by the guide plates and their connections integrated in the gearbox housing. Baffles can be contacted reliably.

Further developments of the invention are presented in the dependent claims. A particularly space-saving option for accommodating the printed circuit board (28) is to form the pocket (38) in a housing projection of the gear housing (6) that serves as a support (27).

Advantageously, some of the guide plates (36) are guided to a plug housing (31) that is in one piece with the transmission housing, where they form plug-in contacts (32) for a connector plug. Further plug contacts (32) are led from the plug housing (31) to a brush bridge (44) and are in one piece with brush connections (33), these guide plates (36) also being an integral part of the transmission housing (6). This measure further reduces the cabling and assembly work, because the contacting takes place in one work step during the assembly process. The integration of the baffle plates (36) in the gear housing (6) gives an exact position assignment, which increases the safety of assembly.

In the present exemplary embodiment, two guide plates (36) are routed from the connector housing (31) to the brush bridge (44) and three additional guide plates (36) from the connector housing (31) to the printed circuit board (28) in order to minimize the contact points.

The brush bridge (44) should expediently be held between the motor housing (43) and the gear housing (6), serve as an end shield and be fitted with chokes whose connections are contacted by the brush insulation displacement contacts (33). This ensures that the number of components to be assembled is as small as possible.

It is further provided that the transmission housing (6) is connected to a motor housing (43) via a seal (42). This means that only one sealing level is required, because the brush bridge is housed entirely within the gearbox housing

For reasons of reliability, a rod-shaped permanent magnet is provided as the sensor transmitter (30) and a Hall sensor is provided for the sensor (29).

In the present application example, the gear housing accommodates a planetary gear (3) and a fail-safe device (4), the electric motor (2), the planetary gear (3), the fail-safe device (4) and the pinion (25 ) of the rack and pinion gear are arranged one after the other on a common axis of symmetry. This compact arrangement enables simple assembly, because most components can be assembled in one joining direction.

The sensor connections and/or the brush connections of the guide plates can be implemented in the form of snow clamp, pinch or welded contacts.

• 1 eine Schnittansicht durch einen Stellantrieb und
• 2 eine räumliche Ansicht eines Getriebegehäuse des Stellantriebs,
• 3 eine Teilschnittansicht durch das Getriebegehäuse,
• 4 eine Innenansicht des Getriebegehäuses,
• 5a ein Zahnstangenabschnitt mit Sensorleiterplatte,
• 5b eine Variante von 5a,
• 5c eine weitere Variante von 5a,
• 6a ein komplettes Zahnstangengetriebe,
• 6b eine weitere Ansicht des Zahnstangengetriebes,
• 7a eine erste Ansicht einer Abstützung mit Leiterplatte,
• 7b eine zweite Ansicht der Abstützung mit Leiterplatte
• 8 eine Innenansicht des Getriebegehäuses ohne Bestückung
• 9 eine Ansicht des Getriebegehäuses mit montierter Bürstenbrücke
• 10 eine Ansicht der Bürstenbrücke an einem Hohlrad und der Leitbleche und
• 11 eine Ansicht der Bürstenbrücke an dem Hohlrad und der Leiterplatte mit Leitblechen.

The invention is explained in more detail below using exemplary embodiments. Show it:

• 1 a sectional view through an actuator and
• 2 a spatial view of a gear housing of the actuator,
• 3 a partial sectional view through the transmission housing,
• 4 an interior view of the gearbox housing,
• 5a a rack section with sensor circuit board,
• 5b a variant of 5a ,
• 5c another variant of 5a ,
• 6a a complete rack and pinion gear,
• 6b another view of the rack and pinion gear,
• 7a a first view of a support with circuit board,
• 7b a second view of the support with circuit board
• 8th an interior view of the transmission housing without equipment
• 9 a view of the transmission housing with mounted brush bridge
• 10 a view of the brush bridge on a ring gear and the baffles and
• 11 a view of the brush bridge on the ring gear and the circuit board with baffles.

1 shows a sectional view through an actuator 1, consisting of an electric motor 2, which is designed here as a commutator motor, a gear housing 6, in which a planetary gear 3 is housed, consisting of a sun wheel 16, which is arranged on a motor shaft 17 and drives planet wheels 18 , which are mounted on a planet carrier 19. The planet gears 18 mesh with a ring gear 20 which, in the present example, is in one piece with a brush bridge. The motor shaft 17 is mounted in a roller bearing 21. The planet carrier includes a driver 22 which is coupled to a fail-safe device 4 . The fail-safe device 4 consists of a spiral spring 23 which is fixed centrally and can be tensioned by the driver 22 at its outer end. The outer end of the coil spring 23 is coupled to a disc 24 rotatably supported on a gear shaft 7 . The gear shaft 7 is mounted in a roller bearing 8 designed as a fixed bearing and the extension of the gear shaft 7 emerges from the gear housing 6 and is firmly connected to an extension piece 41 of the rack pinion 25, which is geared to a rack 26 engaged. The toothed rack 26 is connected directly to the actuator or is designed at its other end as an actuator, for example as a valve disk. The roller bearing is fixed to the transmission housing 6 by an elastic sheet metal part 11 . The toothed rack 26 is supported on a support 27 of the gear housing 6 . A rod-shaped permanent magnet is arranged as a sensor transmitter 30 on the toothed rack. The permanent magnet moves back and forth with the rack. The sensor transmitter 30 is designed in such a way that a north pole alternates with a south pole; this pole transition is detected by a magnetic sensor, a Hall sensor 29 here. The sensor 29 is arranged on a circuit board 28 which is accommodated in a pocket 37 of the transmission housing. The pocket is located within the support 27. The printed circuit board 28 is equipped with contact pins into which sensor clamping displacement contacts of guide plates 36 are in contact. The baffles 36 are an integral part of the transmission housing and are joined therein by archetypes. A portion of the baffles 36 is routed to a connector housing which is integral with the transmission housing. The ends of these baffles form plug contacts 32 which can be connected to a plug connection of a cable harness, for example in a motor vehicle. Another part of the guide plates 36 is led to the brush bridge and contacted there with this via insulation displacement connections. The electric motor includes a pot-shaped housing with a mounting flange. This mounting flange is connected to the gearbox housing via screw connections. The gearbox housing is extended on three sides for the screw connection.

2 shows how the roller bearing 8 is connected to the transmission housing 6 in the present exemplary embodiment. The elastic sheet metal part 11 overlaps the outer ring of the roller bearing 8 and has two elastic arms 12 in which openings for receiving fastening screws 13 are left free. The fastening screws 13 are screwed directly into the plastic material of the transmission housing 6 . A projecting housing ring 14, which is concentric to the roller bearing 8 and serves as a flange, extends on the circumference of the sheet metal part 11. The gear shaft protruding from the gear housing 6 is provided with the pinion 25 by being pressed on. The pinion 25 is outside of the gear case 6 in engagement with the rack 26 which is supported on the support 27 of the gear case 6 . The extension of the rack forms a valve rod 39 on which a valve plate is formed (not shown here).

3 is a partial sectional view of gear housing 6 with connector housing 31, brush insulation displacement contacts 33, pocket 38 with circuit board 28 accommodated therein, roller bearing 8, gear shaft 7, with pinion 25 pressed on, rack 26 with sensor transmitter 30 and support 27 .

4 shows an interior view of the gear housing 6 with the gear shaft 7, the roller bearing 8, the printed circuit board 28, sensor insulation displacement contacts 34, which overlap and make contact with the contact pins 35 of the printed circuit board 28, the plug housing 31, the plug contacts 32 and the brush insulation displacement contacts 33.

5a shows a rack section 26 with a receptacle 37 for the sensor transmitter in the form of a cylinder section-shaped depression on a side adjoining the toothed side of the rack 26 and the printed circuit board 28 with the contact pins 35 and the sensor 29. In the present example, the rack is for an adhesive connection with the Sensor transmitter trained.

5b shows a variant of 5a , The sensor transmitter 30 being accommodated in a receptacle 37 of the toothed rack 26 which is in one piece with the side walls 40 . The receptacle 37 with the side walls and the sensor transmitter 30 are shaped in such a way that a snap connection between the sensor transmitter 30 and the toothed rack is possible. In this case too, the sensor transmitter 30 can also be glued in place.

5c shows a different view of 5 without sensor transmitter.

In 6a the assembly is off 5b supplemented by baffles 36 which are an integral part of the gearbox housing. The gearbox housing is largely hidden. Only the support 27 on which the rack 26 is supported is shown. The pinion 25 pressed onto the transmission shaft 7 is shown with the toothed rack. The gear shaft 7 is firmly connected to the inner ring of the roller bearing 8 .

6b indicates 6a from a different perspective. The pocket 38 in which the printed circuit board 28 is arranged can be seen more clearly here.

the 7a and 7b highlight the support 27 of the gearbox 6 in which the pocket 38 is placed. In 7b In particular, the contact connection between the guide plates 36 and the contact pins 35 of the printed circuit board via the sensor insulation displacement contacts 34 can be clearly seen.

8th shows an interior view of the transmission housing 6 without equipment, with the connector housing 31, the plug contacts 32, the sensor insulation displacement contacts 34, the brush insulation displacement contacts 33, thread 49 (where the thread can also be produced by self-tapping screws during assembly) for fastening the Motor housing 43 and screw passages 47 for attaching the gear housing 6 to a customer attachment. It can be clearly seen that the plug-in direction for the printed circuit board and for the brush bridge is the same.

In 9 shows a view of the transmission housing 6 with the brush bridge 44 mounted. The brush bridge has brushes 46 and 45 throttles. The ends of the chokes 45 make contact with the brush insulation displacement contacts 33 .

the 10 and 11 show the brush bridge 44 and the guide plates 36a, 36b, 36c, 36d, 36e, which end on the one hand as plug contacts 32a, 32b, 32c, 32d, 32e and on the other hand as clamping cutting contacts 33a, 33b or 34c, 34d and 34e. In 11 the printed circuit board 28 is also shown. The gear housing 6 is in the 10 and 11 hidden. In 11 connecting webs 48 can be seen between the guide plates 36a and 36b, 36b and 36c, 36c and 36d and between 36d and 36e. These connecting webs are separated before or during the encapsulation of the guide plates with plastic material.

Reference List

1

actuator

2

electric motor

3

planetary gear

4

Fail-safe facility

5

rack and pinion gear

6

gear case

7

gear shaft

8th

roller bearing

9

stock pick-up

10

outer ring

11

sheet metal part

12

elastic arm

13

mounting screw

14

casing ring

15

inner ring

16

motor sprocket

17

motor shaft

18

planet wheel

19

planet carrier

20

ring gear

21

engine mount

22

driver

23

spiral spring

24

disc

25

rack pinion

26

rack

27

support

28

circuit board

29

sensor

30

sensor transmitter

31

connector housing

32

plug contacts

33

brush connection

34

sensor connection

35

contact pin

36

baffle

37

Recording (for givers)

38

bag (for circuit board)

39

valve rod

40

sidewall

41

extension piece

42

poetry

43

motor housing

44

brush bridge

45

throttle

46

brush

47

screw passages

48

connecting bar

49

thread

Claims (6)

Actuating drive (1) for actuating a linear unit, in particular an exhaust gas recirculation valve, with an electric motor (2), a reduction gear, which has a rack and pinion gear (5) with a pinion (25) and a rack (26), a gear housing (6) and a sensor (29) fixed to the housing for detecting a movement state of the actuator, a sensor transmitter (30) being fastened to the rack (26) and being arranged between the rack (26) and the gear housing (6), characterized in that the sensor (29) is arranged on a circuit board (28) which is accommodated in a pocket (38) of the gearbox housing, that the circuit board (28) has contact pins (35) which are in contact with sensor connections (34) in the gearbox housing (6), that the Sensor connections (34) with guide plates (36) are in one piece, which are an integral part of the transmission housing (6), that the pocket (38) in a support (27) serving as a projection of the transmission housing it (6) is molded in such a way that part of the guide plates (36) are led to a plug housing (31) which is one piece with the gear housing, and plug contacts (32) form there for a connection plug, that further plug contacts (32) from the plug housing (31) are led to a brush bridge (44) and are in one piece with brush connections (33), these baffles (36) also being an integral part of the gear housing (6), that baffles (36) are led from the connector housing (31) to the brush bridge (44). and further guide plates (36) are routed from the connector housing (31) to the printed circuit board (28), the guide plates being an integral part of the gear housing (6), that the brush bridge (44) is held between the motor housing (43) and the gear housing (6), serves as an end shield and are equipped with chokes whose connections are contacted by the brush connections 33. actuator after claim 1 , characterized in that the transmission housing (6) is connected to a motor housing (43) via a seal (42). actuator after claim 1 , characterized in that the sensor (29) is a Hall sensor and the sensor transmitter (30) is a rod-shaped permanent magnet. actuator after claim 1 , characterized in that the gear housing accommodates a planetary gear (3) and a fail-safe device (4). actuator after claim 4 , characterized in that the electric motor (2), the planetary gear (3), the fail-safe device (4) and the pinion (25) of the rack and pinion gear are arranged one after the other on a common axis of symmetry. Actuating drive according to at least one of the preceding claims, characterized in that the sensor connections and/or the brush connections are designed in the form of insulation displacement, pinch or welded contacts.

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