EP2054634A2

EP2054634A2 - Actuating device with position sensing device

Info

Publication number: EP2054634A2
Application number: EP07802690A
Authority: EP
Inventors: Werner Schnabel; Alessandro Spathas; Uwe Grass
Original assignee: Mahle International GmbH
Current assignee: Mahle International GmbH
Priority date: 2006-08-23
Filing date: 2007-08-17
Publication date: 2009-05-06
Also published as: WO2008022975A2; DE102006039521A1; CN101523060A; US20100089168A1; WO2008022975A3; DE102006039521B4

Abstract

The present invention relates to an actuating device (12) with a pressure cell (1) for actuating mechanical systems by means of an actuating rod (13). To determine intermediate positions of the actuating rod (13) in a simple and inexpensive way, a housing (17) of the pressure cell (1) consists entirely or partially of a translucent plastic. Furthermore, a lug (4, 5) that is firmly connected to the actuating rod (13) is provided inside a chamber (14) of the pressure cell (1), with a light barrier (3, 6) arranged outside the pressure cell (1) to detect the position of the lug (4, 5).

Description

Actuating device with position detection device

The present invention relates to an actuating device with a pressure cell for actuating mechanical systems by means of an actuating rod, wherein the pressure cell having two divided by a membrane chambers having different pressure ratios. The invention also relates to a position detection device for generating an electrical position signal correlating with a relative position between two components. Furthermore, the invention relates to an actuator with such an actuator and with such a position detection device.

For the actuation of mechanical systems, eg for the adjustment of flaps or for the actuation of valves, electrically operated, hydraulic and pneumatic actuators can be used. Pneumatically operating actuators regularly include a pressure cell, so a pneumatic system in which one side of a membrane is loaded by negative pressure, while the other side is loaded by pressure or ambient pressure. From the resulting pressure difference results in a force the membrane, which passes these by means of an actuating rod. This is a linear force movement. The force on the membrane is counteracted by a spring force which assigns the membrane a path corresponding to the pressure difference. A position report on where the actuating rod is currently located, does not take place.

In order to obtain position reports or position reports, it is possible to use mechanical switches or magnetic systems, e.g. Hall probes, use, for example, to determine the respective end positions of the actuating rod. Hall sensors can also be used to detect liners. The disadvantage here is that switches and Hall sensors are expensive, in particular fall the large or long magnets for the operation of the Hall sensors in the weight. Since the magnetic position detection works without contact, so far the associated increased costs are accepted.

From DE 20 2006 000 528 Ul a made of a plastic for optical radiation of a sensor transparent sensor housing is known.

From US 3,100,997 a pressure cell is known in which a membrane separates an evacuated space from a measuring space and carries a screen with juxtaposed transparent and opaque strips, wherein the screen is positioned adjustable in an optical path of a light barrier. The pressure cell has a glass housing and works with a light barrier whose transmitter and receiver are arranged on the outside of the housing and which deflects the light of the transmitter through the light path to the receiver via a mirror arrangement.

The present invention is concerned with the problem of providing for an actuator of the type mentioned above or for a position detection device of the type mentioned or for an equipped with an actuator and a position detection actuator actuator an improved embodiment, which is particularly characterized in that liners and End positions of a component, in particular an actuating rod, can be determined in a simple and inexpensive manner.

This problem is solved according to the invention by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The present invention proposes for the solution of this problem, three different, independent solutions, namely an actuator, a position detecting device and an actuator. In this case, all three solutions are based on the common superordinate idea, with two components which are adjustable relative to one another, which equip one with a flag and the other with a light barrier, which cooperates with the lug for generating an electrical position signal. The position detection thus also works without contact and comes doing without expensive magnets, which makes them relatively inexpensive to implement. In particular, photoelectric barriers can nowadays be realized with extremely inexpensive semiconductor elements, such as light-emitting diodes and transistors.

For working with a pressure cell actuator, this object is achieved in that a housing of this pressure cell is wholly or partially made of a translucent plastic, wherein within one of the two chambers of the pressure cell, which forms a clean room, a firmly attached to the operating rod flag is provided , wherein outside of the pressure cell, a light barrier for detecting the position of the flag is arranged. As a result, with simple and inexpensive means, a contactless system can be provided in an operating device operating with a pressure cell in order to determine a position report or a position signal for the actuating rod. In the proposed actuator thus a position detection device is integrated, which is formed by the flag and the cooperating photocell.

The problem underlying the present invention is solved in the proposed position detection device in that it comprises two bidirectionally arranged in a stroke direction adjustable components, one of which is equipped with the flag and the other with the light barrier. As a result, the light barrier interacting with the flag can be varied as a function of the lativlage between the flag and the light barrier generate a correlated with the relative position of the two components electrical position signal. The position detection device formed in this way can likewise be realized inexpensively. Furthermore, it is particularly easy to use with an actuator that serves to bidirectionally drive an actuator. For this purpose, only the component of the position detection device carrying the flag has to be coupled to an actuating rod serving to drive the actuator.

The problem underlying the invention is also solved by an actuator which either comprises the actuator according to the invention with integrated position detection or any actuator and the position detection device according to the invention.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are shown in the drawings and will be described in the following. Described spelling, wherein like reference numerals refer to the same or similar or functionally identical components.

Show, in each case schematically,

1 is an actuating device with a pressure cell with an actuating rod, an uncoded flag and a fork light barrier,

2 an actuator with a pressure cell with an actuating rod, a flag with coding and a light barrier,

3 shows an embodiment of a coded flag,

4 is a partial view of another embodiment of an actuator with a pressure box with an actuating rod and a flag with coding,

5 shows a position detection device with an uncoded flag and a fork light barrier,

6 shows a position detection device with a coded flag and a light barrier,

7 shows an embodiment of a coded flag, 8 is a partial view of another embodiment of a position detection device with a coded flag.

1 to 8 are schematic representations, with only the essential components for understanding the invention are shown.

For some time, translucent plastics have been known. These are also permeable to laser light. Particular embodiments of these translucent plastics look black to the human eye, but are transparent to light of a particular wavelength. If, for example, a housing of a vacuum side of a pressure cell is manufactured from this material and a flag is positioned in the housing on the negative pressure side of the diaphragm, then a light barrier can be placed externally on the pressure cell, which can cooperate with the inner lug. The light of the light barrier passes almost unhindered through the at least for the wavelength of the light of the light barrier permeable plastic and thus no expensive cable bushings are necessary. The light barrier, which is actuated by the inner flag or interacts with the inner flag, may be a forked light barrier or a reflex light barrier or consist of a light barrier arrangement, which consists of at least two components, namely a transmitter, for example in the form of an emitter diode, and a receiver, eg of a photosensitive transistor. Fig. 1 shows an embodiment of an actuator with a pressure box with a non-coded flag and a fork light barrier.

According to FIG. 1, an actuating device 12 comprises a pressure cell 1 with an actuating rod 13, which has a lug 4 in a chamber 14. The pressure cell 1 also includes a diaphragm 15 which separates one chamber 14 from another chamber 16. 2 denotes a vacuum connection. With the help of a forked light barrier 3, a so-called end position of the actuating rod 13 can be determined. This may in particular be an upper or lower limit position. The end position can be checked most easily by means of a fork light barrier 3 or a reflex light barrier, since both devices consist of only one unit. This unit is attached to or on the pressure box 1 so that no dirt can penetrate into the light path.

The pressure cell 1 has a housing 17, which consists of a plastic which is permeable to the light of the light barrier 3. Accordingly, the light barrier 3 can be arranged on the outside of the housing 17 and nevertheless interact with the lug 4 arranged in the interior of the housing 17. The chamber 14, in which the flag 4 is arranged, is preferably designed as a clean room. This clean room is sealed, for example, from the environment. The light barrier 3 together with the lug 4 forms a position detection device 18. This position detection device 18 is structurally integrated here into the actuating device 12, resulting in a total of one unit, which can also be referred to as an actuator 19. Such an actuator 19 can be used for bidirectional driving of an actuator, not shown here, of an essentially any mechanical system. For this purpose, the actuating rod 13, at its remote from the flag 4 end portion 20 can be coupled with said actuator.

Fig. 2 shows an actuating device 12 with a pressure cell 1, which is equipped with an actuating rod 13. In this embodiment, the recognition of intermediate layers of the actuating rod 13 is possible. For this purpose, a plurality of light barriers 6 are installed, wherein in the illustrated embodiment, only one light barrier 6 is shown. The illustrated in Fig. 2 pressure cell 1 has a coded flag 5. The coded flag 5 is shown in detail in Fig. 3. In this embodiment too, the at least one light barrier 6 and the lug 5 form a position detection device 18, which is integrated into the actuating device 12. The unit thus formed again forms an actuator 19 for bidirectionally driving an actuator, not shown here, of any mechanical system.

According to FIG. 3, the flag 5 can be divided into regions or areas or fields, whereby unshaded areas let the light pass, while hatched areas do not let the light through. This light transmission refers to at least the wavelength of the light barrier used 6. If now four areas in a row, so-called Prüfreihe 7, arranged over the width of the flag 5, four light barriers are required and it is a position report of four bits possible. If, for example, a flap is adjusted by 90 °, this means a positioning of 5.6 °.

For example, in another less expensive solution, only a single transmitter, e.g. a corresponding emitter diode may be used which sends light through a mirror array onto the photosensitive receivers, for example transistors. The mirror arrangement can be formed for example by injected mirrors, which work with total reflection in the plastic material. As a result, significantly more bits can be realized inexpensively. Fig. 4 shows an embodiment in which this solution is realized. In this case, in Fig. 4 with 9 a translucent housing, with 8 the mirror assembly, with 5 the coded flag, with the emitter diode 10 and 11, the photosensitive transistors, which serve as a receiver, characterized.

In another embodiment, not shown here, the position of the flag can basically be determined in the same way as the cursor position is determined using a ballless computer mouse. In such an embodiment, a reflection light barrier is used. det, wherein the relative movement of the flag is determined by a corresponding chip. However, this adjustment is required now and then for the present application. This can for example always be done when reaching the end position. Accordingly, the position of the flag from the end position should be calculated again and again.

The fact that a laser-suitable plastic material for the housing 9 or 17 of the pressure cell 1 is used, the pressure cell 1 can also be welded by means of a laser. In the following, the advantages of the present invention will be briefly enumerated, at least for the embodiments shown in FIGS. 1 to 4:

1. Use of a light barrier as a switching element. This is inexpensive and provides a safe signal.

2. Use of a permeable for the wavelength of the emitter diodes black plastic.

3. The components of the light barrier are located outside of the under- or over-pressurized space, so no expensive and unsafe feedthroughs are necessary.

4. The flag for actuating the light barrier is located in the clean room on the lower or overpressure side of the pressure cell. 5. By using multiple receive transistors intermediate positions can be detected. The flag has a corresponding digital encoding.

6. The plastic part of the under- or overpressure side can be sprayed so that mirrors are formed, so that the light of a single emitter diode can be distributed.

According to FIGS. 5 and 6, a position detection device 21 comprises a first component 22 and a second component 23. With the aid of the position detection device 21, an electrical position signal can be generated which correlates with the relative position between the two components 22, 23. For this purpose, the two components 22, 23 within the position detection device 21 to each other in a direction indicated by a double arrow stroke direction 24 are arranged bidirectionally adjustable relative to each other. For example, the first component 22 is mounted on the second component 23 in a stroke-adjustable manner. For this purpose, purely by way of example and without limiting the generality, the second component 23 may have a rail (not shown here) for longitudinal guidance of the first component 22.

The first component 22 has a lug 25, which is stationary relative to the first component 22. The second component 23 has at least one light barrier 26, which is stationary relative to the second component 23. This light barrier 26 is arranged in an unspecified adjustment of the flag 25. In that regard, the light barrier 26 with the Flag 25 cooperate to generate depending on the relative position between the flag 25 and light barrier 26, an electrical position signal, which then correlates with the relative position of the two components 22, 23 to each other.

The light barrier 26 may in principle be arranged outside a housing 27 indicated by a broken line, which then forms a component of the second component 23. In this case, the housing 27 consists of a material permeable to the light of the light barrier 26, in particular plastic. However, the embodiment shown here is preferred, in which the light barrier 26 is disposed within the housing 27, of which only a small portion is shown here. This housing 27 expediently also forms part of the second component 23.

In the embodiment shown in Fig. 5, the light barrier 26 is configured as a fork light barrier. Such fork light barrier 23 can be prefabricated and assembled as a unit, which simplifies their handling.

According to Fig. 6, the use of a coded flag 28 may be provided in another embodiment. According to FIG. 7, the coded lug 28 can consist of a large number of adjacent fields or areas or regions 29, of which one areas 29, shown hatched, are not permeable at least to the light of the light barrier 26 and of which the others, here unshaded, represent Asked areas 29 are permeable at least for the light of the light barrier 26. The selected arrangement of adjacent light-transmissive and opaque regions 29 forms a digital coding of the lug 28. In the example, in the width direction of the lug 28, four such regions 29 are arranged side by side in a test series 30. Accordingly, a 4-bit coding can be realized. It is clear that in the respective test series 30, more or fewer regions 29 can be arranged next to one another.

In the embodiment shown in FIG. 6, in the width direction of the lug 28, which extends transversely to the stroke direction 24, four or more or fewer light barriers 26 can be arranged next to one another corresponding to the number of juxtaposed regions 29 within the respective test lane 30. In Fig. 6, however, only one such light barrier 26 is shown. In another embodiment, it is basically possible to provide a single transmitter that sends light to multiple receivers. In this case, the respective light barrier 26 according to FIG. 8 can operate with a mirror arrangement 31 which divides the light originating from a common light transmitter (emitter diode) 32 onto a receiver arrangement 33. The receiver arrangement 33 can have a number of separate receivers, in particular photosensitive transistors, corresponding to the bit depth of the coding of the lug 28. Likewise, the receiver arrangement 33 can consist of a common receiver, in particular in the form of a photosensitive transistor, which has a ne the bit depth of the coding of the flag 28 can separately detect and evaluate corresponding number of adjacent areas.

In FIG. 8, the coded lug 28 and, purely by way of example, the housing 27, which is likewise configured to be light-permeable here, can be seen, at least for the light of the light barrier 26.

The cooperating with this coded flag 28 photocell 26 thus has on one side of the flag 28 at least one light emitting emitter diode and on the other side of the flag 28 at least one photosensitive transistor.

The mirror assembly 31 can be injected in particular in plastic, working with total reflection. In particular, the mirror assembly 31 may be injected into the housing 27.

In another embodiment, not shown here, the light barrier 26 may be designed as a reflection light barrier, which detects by means of a corresponding chip (integrated circuit), the movement of the flag 28 and the movement of the flag 25 and converted into a corresponding position signal. Such reflection light barriers, which cooperate with such a chip for position determination, are known for example from computer technology and are used to determine a cursor position on the image. screen, which is operated with a mouse. The computer mouse used for this purpose works without a ball, but with at least one such reflection light barrier, whereby the relative movement of the mouse relative to a background can be detected. The movement signal that can be determined thereby can be used to control the cursor. This principle can be used here for the position detection of the flag. It is expedient to carry out a position comparison with a reference position from time to time. This can be carried out particularly easily when an end position of the flag or components is reached.

As already explained above, the second component 23 can form a housing into which the first component 22 protrudes. The light barrier 26 can then be arranged within the housing 27. According to the embodiments of FIGS. 5 and 6, the position detection device 21 may preferably form part of an actuator 34. Said actuator is used for bidirectional driving of an actuator, not shown here of an essentially any mechanical system. The actuator 34 comprises, in addition to the position detection device 21 also an actuator 35, which is here purely by way of example and without limiting the generality indicated by a piston-cylinder unit. The actuating device 35 serves to actuate a bidirectionally adjustable actuating rod 36, which is formed here by the first component 22. Likewise, it may be a separate actuating rod 36, in which case the first component 22 of the position sensor The detection device 21 is suitably coupled to this actuating rod 36. The actuating rod 36 can be drive-connected, for example, via a connecting region 37 with the actuator to be driven by means of the actuator 34.

The actuating device 35 can basically be formed by the actuating device 12 explained in more detail with reference to FIGS. 1 to 4. The position detection device 21 is then virtually integrated in the actuating device 35. Alternatively, the actuating device 35 and the position detection device 21 are fundamentally separate systems which interact in a suitable manner. In this case, it is possible, in particular, to completely accommodate the position detection device 21 in a housing of the actuating device 35. Thereby, an integrated actuator 34 may be provided which integrally includes the actuator 35 and the position detecting device 21.

The actuating device 35 can thus operate pneumatically and accordingly have in particular a pressure cell 1. Alternatively, the actuator 35 may also operate hydraulically. Likewise, an electrically operating actuator 35 is possible.

The actuator 34 may for example be used to actuate a valve member in an exhaust gas recirculation device. For example, the actuating rod 36 may be the Actuate valve member of an exhaust gas recirculation valve to thereby adjust the exhaust gas recirculation rate can. Alternatively, with the aid of the actuator 34, for example, an actuator of an exhaust gas turbocharger can be actuated. For example, an exhaust gas turbocharger has a wastegate valve with which, for low loads, the high pressure side of the turbine can be connected to the low pressure side of the turbine. Furthermore, the exhaust gas turbocharger can be equipped with an adjustable vane geometry. The actuator 34 can thus be used to operate the wastegate valve or the vane adjustment.

*****

Claims

claims

1. actuating device for actuating mechanical systems by means of an actuating rod (13),

- wherein a pressure cell (1) is provided, the two by means of a membrane (15) partitioned chambers (14, 16) having different pressure ratios,

- wherein the membrane (15) is drive-connected to the actuating rod (13),

- Wherein a housing (9, 17) of the pressure cell (1) consists wholly or partly of a translucent plastic,

- Wherein within one of the two chambers (14) which forms a clean room, with the actuating rod (13) fixedly connected flag (4, 5) is provided,

- Outside of the pressure cell (1) at least one light barrier (3, 6) for detecting the position of the flag (4, 5) is arranged.

2. Actuating device according to claim 1, characterized in that the light barrier (3) is a fork light barrier, which is arranged in the end region of the flag (4) and with which the end position of the flag (4) can be detected.

3. Actuating device according to claim 1 or 2, characterized,

- that the flag (5) has an array of adjacent translucent and non-translucent surfaces which together form an encoding,

- That at least one light-emitting emitter diode and on the other side of the flag (5) at least one photosensitive transistor are arranged outside the chamber (14) on one side of the flag (5).

4. Actuating device according to one of claims 1 to 3, characterized in that the plastic part of one of the chambers (14) is injection molded in such a way that on its inside mirror (31) arise, which distribute the light of an emitter diode.

5. Actuating device according to one of claims 1 to 4, characterized in that the light barrier is a reflection light barrier, wherein the movement of the flag (4, 5) is registered by means of a chip.

6. Position detection device for generating a correlation with a relative position between two components (22, 23) electrical position signal,

- Wherein one component (22) on the other component (23) in a stroke direction (24) is arranged bidirectionally adjustable, - wherein the first component (22) has a lug (25, 28),

- Wherein the second component (23) at least one in the adjustment path of the flag (25, 28) arranged light barrier (26), which in dependence of the relative position between flag

(25, 28) and the light barrier (26) generates an electrical position signal correlated with the relative position of the two components (22, 23).

7. Position detecting device according to claim 6, characterized

- that the lug (28) has an array of adjacent translucent and non-translucent surfaces (29) which together form an encoding,

- That the light barrier (26) on one side of the flag

(28) at least one light-emitting transmitting device and on the other side of the flag (28) has at least one photosensitive receiving device.

8. Position detecting device according to claim 7, characterized in that the second component (23) has a mirror arrangement (31) for dividing the light of a transmitting device (32) on a plurality of receiving devices or on a receiver arrangement (33).

9. Position detecting device according to one of claims 6 to 8, characterized in that the light barrier (26) is designed as a reflection light barrier, which determines the movement of the flag (25, 28) by means of a corresponding chip and converts it into a position signal.

10. Position detecting device according to one of claims 6 to 9, characterized

- That the second component (23) has a housing (27) into which the first component (22) protrudes, and / or

- That the housing (27) at least partially made of a translucent plastic, wherein the light barrier

(26) transmitter side and / or receiver side outside the housing (27) is arranged.

11. Actuator for bidirectionally driving an actuator of a mechanical system,

- with an actuating device (12, 35) for actuating a bidirectionally adjustable actuating rod (13, 36) which can be drive-connected to the actuator to be driven,

- with a position detection device (18; 21) for generating an electrical position signal correlated with a relative position of the actuating rod (13; 36),

wherein either the actuating device (12) according to one of claims 1 to 5 is configured and the position detection device (18) by the with the flag (4, 5) cooperating light barrier (3, 6) is formed or the position detection device (21) according to one of claims 6 to 10 is configured.