GB2468779A

GB2468779A - Displacement transmission structure, for a position sensor of a turbocharger actuator, comprising a compensating slide mechanism

Info

Publication number: GB2468779A
Application number: GB1004531A
Authority: GB
Inventors: John Gerhard
Original assignee: Tyco Electronics AMP GmbH
Current assignee: TE Connectivity Germany GmbH
Priority date: 2009-03-19
Filing date: 2010-03-18
Publication date: 2010-09-22
Anticipated expiration: 2030-03-18
Also published as: FR2943413A1; GB2468779B; DE102009013546B3; FR2943413B1; GB201004531D0

Abstract

A transmission device (37) for a position sensor (4) for detecting the position of an actuator piston (5) of a control box (1) for a turbocharger, comprising a transmission element (38) which is linearly displaceable in an adjustment direction (V), by means of which element a position signal which is representative of its position and can be detected by the position sensor (4) can be generated, and with a compensating joint (39), by means of which a relative rotation between the transmission element (38) and actuator piston (5) in at least two axes of rotation extending at right-angles to one another and at right-angles to the adjustment direction (V) can be compensated for. In order to improve the determination of the position of an actuator piston (5) of a control box (1), even if the actuator piston (5) is adjusted in roto-translational manner, a part of the compensating joint (39) forms a compensating slide (53') which is designed to be able to be attached displaceably to the actuator piston (5).

Description

I

Displacement transmission structure for a position sensor of a turbocharger actuator The present invention relates to a transmission device for a position sensor for detecting the position of an actuator piston of a control box for an exhaust gas recirculation valve or a turbocharger with variable geometry, comprising a transmission element which is linearly displaceable in an adjustment direction, by means of which a position signal which is representative of its position and can be detected by the position sensor can be generated, and with a compensating joint, by means of which a relative rotation between the transmission element and actuator piston in at least two axes of rotation extending at right-angles to one another and at right-angles to the adjustment direction can be compensated for.

The invention furthermore relates to a position sensor for detecting the position of an actuator piston of a control box for an exhaust gas recirculation valve or a turbocharger with variable geometry, comprising a sensor housing with a receptacle for guiding the transmission element, and at least one sensor element for emitting a position signal representative of the position of the transmission element.

Furthermore, the present invention relates to an assembly of a control box for an exhaust gas recirculation valve or a turbocharger with variable geometry, comprising a control box with an adjustable actuator piston for setting the exhaust gas recirculation valve or the turbocharger with variable geometry, and a position sensor.

Finally, the present invention concerns a control box for an exhaust gas recirculation valve or a turbocharger with variable geometry, comprising an adjustable actuator piston for setting the exhaust gas recirculation valve or the turbocharger with variable geometry, and a transmission device.

Pneumatic control boxes are used, for example, in pressure charging means operated by exhaust gas flow for internal combustion engines (turbochargers) or in exhaust gas recirculation valves. The control boxes are used to turn the blades of an exhaust gas recirculation valve or a turbocharger with variable geometry and to set the angle of attack thereof. In order to monitor the angle of attack, which correlates with the adjustment position of the driven actuator piston, control boxes may be equipped with a position sensor which detects the position of the piston.

Control boxes known from the prior art are usually designed as simply-acting cylinders, with a piston rod or a transmission member being connected to a membrane fastened to the cylinder or to a piston.

EP 1 852 588 discloses a boost-pressure regulator for exhaust-gas turbochargers of internal combustion engines with a box which is covered by a box cover, with a flexible first membrane which is stretched with its outer edge between the outer edge of the box and the cover, and with a control rod which is guided out of the box in sealed manner, so that its one end lies in the box, where a supporting part for the first membrane is connected securely to the control rod and lies against the first membrane. The membrane, the supporting part and a connection for a vacuum source are arranged such that the control rod is displaced if a partial vacuum is applied. The pressure generator may be coupled to a position sensor which recognises the position of a magnet arranged on the adjustable end of the control rod.

What is problematic with control boxes for an exhaust gas recirculation valve or a turbocharger with variable geometry is that the piston rod driven by the actuator is not moved linearly along the longitudinal axis of the control rod. In order to adjust the blade of a turbocharger and to change its angle of attack, the drive rod of the turbocharger must be displaced in a rotary movement, so that the piston rod of the control box, which is coupled to the drive rod of the turbocharger, likewise has to perform a rotary movement. This rotary movement of the piston rod leads to a tilting or wobbling movement of the actuator piston relative to the housing of the control box, i.e. to a roto-translational adjustment, during which the actuator piston is not displaced purely linearly. This wobbling movement makes it difficult to determine the exact position of the actuator piston, since the position sensor is usually mounted on the control box and the indicator which indicates the position of the piston is arranged on the piston.

In accordance with the known prior art, the transmission member with the indicator may be guided in the sensor itself, the transmission member being pressed against the piston via a return spring. However, such a restoring spring exerts a spring force which influences the movement of the actuator piston. Furthermore, such a spring/mass system is susceptible to the vibrations occurring in combustion engines. If on the other hand the transmission member is mounted directly on the piston, the wobbling or tilting movement of the actuator piston is transmitted to the indicator element, which has an adverse effect on the determination of position and results in measuring inaccuracies.

The object of the present invention is therefore to determine the position of an actuator piston of a control box, even if the actuator piston is adjusted roto-translationally.

This object is achieved in accordance with the invention for the transmission device mentioned first hereinbefore in that a part of the compensating joint forms a compensating slide which is designed to be able to be attached displaceably to the actuator piston.

The position sensor mentioned first hereinbefore achieves this object in accordance with the invention in that the position sensor comprises a transmission device according to the invention.

The assembly of a control box mentioned first hereinbefore achieves this object in accordance with the invention in that a position sensor according to the invention is provided, with, in the assembled state of the assembly, the transmission element being arranged at least in sections in the receptacle of the sensor housing and the part of the compensating joint which forms the compensating slide being attached displaceably to the actuator piston.

Finally, this object is achieved by the control box in accordance with the invention mentioned first hereinbefore by a transmission device according to the invention, the part of the compensating joint which forms the compensating slide being attached displaceably to the actuator piston. "Attached displaceably' in the context of this application covers both direct attachment, in the case of which the compensating slide is mounted directly on the actuator piston and is displaced along the surface thereof, and indirect attachment, in which, although the compensating slide is arranged on the actuator piston and can be displaced relative thereto, it does not have any direct contact with the piston.

The advantage of this surprising solution to the above problem is that the roto-translational movement of the piston can be converted into the linear adjustment of the transmission element by means of the compensating joint in a simple manner. According to the invention, each position of the actuator piston correlates with a given position of the transmission element in the adjustment direction. The compensating joint compensates for the tilting of the actuator piston relative to the housing of the control box, in that the transmission element is rotatably mounted about two axes of rotation arranged at right-angles to one another. The displaceable attachment to the actuator piston compensates for lateral deflection of the actuator piston. In such case, the transmission device according to the invention is particularly compact and robust, since a part of the compensating joint both permits the rotation of the transmission element and forms the displaceable compensating slide. A spring element which presses the transmission element against the piston plate is in accordance with the invention not necessary to compensate for the wobbling movement of the actuator piston. Thus the transmission device according to the invention and the position sensor of the present invention having this transmission device is particularly robust and permits accurate determination of the position of the actuator piston.

The solution according to the invention can be developed further by various embodiments, each of which are advantageous in themselves, which can be combined with each other in any desired manner. The individual advantageous configurations and the advantages associated therewith will be briefly discussed below.

In a first advantageous embodiment, the compensating joint may have a rotary joint, in particular a ball-and-socket joint. A ball-and-socket joint is stable, not susceptible to vibrations, and reliably ensures that a relative rotation between the transmission element and actuator piston in three axes of rotation extending at right-angles to one another and at right-angles to the adjustment direction can be compensated.

A particularly compact and robust construction of the transmission device according to the invention can be achieved in that a shell of the compensating joint forms the compensating slide, thus for example the shell or socket of the ball-and-socket joint can form the compensating slide. In this embodiment, the shell of the compensating joint assumes two functions. Firstly, the shell ensures the necessary rotation of the transmission element relative to the actuator piston, and secondly it represents the compensating slide which is displaceably attached to the actuator piston. In particular, the compensating joint may have a rotary joint, preferably a ball-and-socket joint, and a guide means, the rotary joint, preferably the socket of the ball-and-socket joint, and the guide means forming a sliding bearing. In such case, according to a further embodiment, the guide means may have a fastening element for attaching the transmission device to the actuator piston. The fastening means may for example be a fastening flange, which preferably has a spring seat which forms the stop for one end of the spring which acts upon the actuator piston with a spring force.

In order to facilitate the mounting and the handling of the present invention, the parts of the rotary joint, according to a further advantageous embodiment, may be designed to be able to be undetachably connected together, which can advantageously be achieved in that the parts of the rotary joint are designed to be able to be connected together in a positive manner.

In one particularly advantageous embodiment, the shell of the compensating joint may have a shell body and a shell lid, which can be connected to the shell body, with an opening, the internal width of which is smaller than the external dimension of a joint head which can be received in the shell, which head can be rotatably mounted in the shell. This embodiment enables the joint head and joint shell or shell of the rotary joint to be undetachably joined together in a structurally simple manner. For this, merely the joint head is inserted into the seat of the shell body which is provided. Then the shell body with the shell lid is connected to the shell, the joint head then being arranged in a positive manner in the seat of the shell.

In this case, the internal width of the opening in the shell lid prevents the joint head from being able to be taken out of the seat of the shell without detaching the shell lid from the shell body beforehand.

In order to facilitate the handling and mounting of such a shell or shells, the shell body and the shell lid may be undetachably connected together, preferably via a hinge which connects the shell body and shell lid together and guides the mounting or dismantling of the shell lid on/from the shell body.

The mounting and handling of the transmission device and the position sensor of the present invention can be further developed advantageously in that the compensating joint has a tilting stop which limits the tilting of the transmission element relative to the actuator piston to a maximum angle of inclination. The tilting stop ensures that the transmission device can be arranged on the actuator base such that the transmission element thereof is held in an intended position owing to the tilting stop. This facilitates in particular the introduction of the transmission element into the receptacle of the sensor housing, if the sensor is mounted on the control box.

Furthermore, the compensating joint may have a displacement stop which limits the displacement of the compensating slide on the actuator piston. In this manner, additional stability is imparted to the transmission device according to the invention, and it is ensured that the end of the transmission element which is to be introduced into the receptacle of the sensor housing cannot be displaced further on the actuator piston than is absolutely necessary in order to compensate for the roto-translational adjustment of the piston and to permit simple mounting of the sensor body on the control box. The displacement stop can advantageously be arranged on the guide means of the compensating joint.

One particularly advantageous embodiment of the transmission element provides for the latter to be designed as a transmission rod, on one end of which at least one indicator, by means of which the position signal can be generated, and on the other end of which a part of the compensating joint is arranged, preferably a part of the rotary joint and particularly preferably the joint head. In this manner, one component of the compensating joint is arranged directly on the transmission element, which facilitates mounting and improves stability, since the transmission element is connected directly to the joint via the part of the compensating joint arranged thereon.

According to a further advantageous embodiment, the receptacle of the sensor housing has an introduction opening which is surrounded by a ramp structure with a guide incline extending in the direction of the introduction opening. This embodiment facilitates the insertion of the transmission element into the receptacle of the sensor housing upon mounting of the position sensor, for example on a control box, because the distal, i.e. the free, end of the transmission element upon mounting is inserted such that it hits the ramp structure, slides along the guide incline and is guided into the introduction opening.

In one particularly advantageous embodiment, the ramp structure may be formed by guide elements, the maximum distance between adjacent guide elements being smaller than the cross-sectional width of the section of the transmission element which is introduced into the receptacle. This embodiment is particularly light and economical on material and at the same time ensures that the transmission element, upon the mounting of the position sensor on the control box, always hits the guide elements of the ramp structure. In particular, it is advisable to form the guide elements as guide ribs, the guide inclines of which, viewed at right-angles to the plane in which the introduction opening lies, are arranged in a star-shape

around the introduction opening.

Since the mounting of the position sensor on the control box is normally carried out by customers, it is desirable for blind mounting of the control box and position sensor to be possible. This can be achieved, according to a further advantageous embodiment, in that the maximum angle of inclination permitted by the tilting stop is smaller than the inclination of the guide incline relative to the introduction opening. The introduction opening of the sensor housing, which is placed on the control box substantially along the centre line, is normally oriented at right-angles to the centre line. Also, the actuator piston upon mounting usually lies at right-angles to the centre line, the transmission element of the transmission device attached to the piston being tilted with regard to the centre line at most by the maximum angle of inclination. If the maximum angle of inclination of the tilting barrier which forms the tilting stop is set to an angle which is less than the inclination of the guide incline, it is ensured that the free end of the transmission element upon mounting of the position sensor meets the ramp structure at such a mounting angle that the tip of the transmission element is guided in the direction of the introduction opening and not away therefrom.

Furthermore, the lateral distance from the centre line of the introduction opening to the outer edge of the ramp structure may be greater than the maximum possible lateral deflection of the transmission element. The centre line of the introduction opening likewise serves as reference quantity for the lateral deflection, which centre line normally coincides with the linear adjustment direction of the transmission element and the centre line of the control box and of the position sensor. Such a configuration of the ramp structure and a maximum possible lateral deflection of the transmission element adapted thereto, which deflection is limited by the displacement stop, can be ensured in that the distal end of the transmission element, upon the mounting of the position sensor on the control box, always hits the ramp structure, which permits blind mounting of the position sensor on the control box.

The invention will be explained in greater detail below by way of example using advantageous embodiments with reference to the drawings. The embodiments described merely represent possible configurations, in which however the individual features, as described above, can be realised or omitted independently of each other.

Fig. I shows a diagrammatic side view of a control box with a piston rod, which represents the actuating element of an exhaust gas recirculation valve or a turbocharger with variable geometry, according to one embodiment of the present invention; Fig. 2 shows a diagrammatic, perspective sectional view of the control box shown in Fig. I; Fig. 3 shows a diagrammatic representation of the kinematic chain from the actuating element of the turbocharger via the piston rod, the actuator piston up to the components of the transmission device; Fig. 4 shows a diagrammatic perspective view of a transmission element of the present invention according to a first embodiment; Fig. 5 shows a diagrammatic perspective view of a shell of the compensating joint of the present invention according to a first embodiment; Fig. 6 shows a diagrammatic perspective view of the transmission device according to the invention according to a first embodiment, in which a guide means of the compensating joint of the first embodiment is not yet assembled with the further elements of the transmission device; Fig. 7 shows a diagrammatic perspective view of the transmission device according to the invention according to the first embodiment of the assembled state; Fig. 8 shows a diagrammatic sectional view along the centre line of the assembly comprising the sensor and the control box of Figs. I and 2 in a pre-mounting position, in which the sensor and the control box are present separately from each other; Fig. 9 shows a perspective view of the sensor body of the previous figures; and Fig. lOshows a diagrammatic perspective sectional view of the position sensor according to the invention and control box with a transmission device according to a second embodiment.

Fig. I shows a diagrammatic side view of a control box 1, which comprises an adjustable piston rod 2 which drives an actuating element 3, e.g. an actuating member of an exhaust gas recirculation valve or of a turbocharger with variable geometry (not shown). A position sensor 4, by means of which the actuating position of the actuator piston 5 which drives the piston rod 2 can be determined, is mounted on the control box I. The control box I comprises a lower box part 6 and a box cover 7, which in the assembled state form the cylindrical actuator housing 8. In the interior of the actuator housing 8, a membrane 9 is arranged between the lower box part 6 and the box cover 7 such that the membrane 9 divides the actuator housing 8 into two pressure chambers 10, II. The two pressure chambers 10, II are arranged substantially symmetrically around a centre line M of the control box I. The edge 12 of the membrane 9 lies against a shoulder 13 which runs around the edge of the box cover 7. The edge of the lower box part 6 is designed as a fold 14 which is formed around the shoulder 13 on the box cover 7 and the edge 12 of the membrane 9 and thus compresses the membrane 9 in a sealing manner between the box cover 7 and lower box part 6 and at the same time connects the box cover 7 and the lower box part 6 together.

In this example of embodiment, the membrane 9 is in the form of a pot-type membrane 9'.

The flat membrane base 15 thereof is reinforced on the side of the base 16 of the actuator piston 5 which faces the box cover 7, which base, in the initial state shown in Fig. 2, lies substantially parallel to the underside 17 of the box cover 7 and to the base 18 of the lower boxpart6.

The base 17 of the box cover 7 has an opening 19 for mounting the position sensor 4 on the control box 1. A fastening ring 20 is attached to the outside of the base 17 of the cover 7, which ring forms a circular limitation around the opening 19. The fastening ring 20 is provided with a plurality of tongues 21 which form a folded seam connection for mounting the sensor housing 22 of the position sensor 4 on the control box 1. For mounting, the sensor housing 22 has a fastening collar 23 which projects laterally from the sensor housing 22. In the assembled state, the fastening collar 23 lies in the fastening ring 20 and the tongues 21 surround the fastening collar 23 such that the sensor housing 22 is crimped to the fastening ring 20 of the box cover 7.

If the sensor housing 22 of the position sensor 4 is connected to the control box 1, the sensor housing 22 closes the opening 19 in the base 17 of the box cover 7. In order to ensure an airtight closure between the fastening collar 23 of the sensor housing 22 and the fastening ring 20 of the cylindrical box cover 7, the fastening collar 23 is provided with a circumambient groove 24 in which a sealing ring 25 is arranged.

In this arrangement, the membrane 9 divides the actuator housing 8 into a vacuum chamber 10 and a pressurised or ambient-pressure chamber 11.

The vacuum chamber 10 is the region in the interior of the actuator housing 8 which is surrounded by the cylindrical box cover 7, the membrane 9, the actuator piston 5 and the sensor housing 22 which seals off in an airtight manner with the fastening ring 20 of the box cover 7. The casing surface of the cylindrical box cover 7 is provided with a vacuum connection 26 which is connected to the vacuum chamber 10 and to which a partial-vacuum generator (not shown) for evacuating and generating a partial vacuum in the vacuum chamber 10 can be connected.

The ambient-pressure chamber 11 is surrounded by the cylindrical lower box part 6 and the pot-type membrane 9'. The casing surface of the cylindrical lower box part 6 is provided with an aeration hole 27 so that ambient pressure always prevails in the ambient-pressure chamber 11.

In the vacuum chamber 10 there is arranged a spring 28 which is supported on one side on the base 17 of the box cover 7 and the other end of which is supported in the interior of the pot-shaped actuator piston 5. The spring exerts a spring force which pushes the actuator piston 5 downwards, i.e. in the direction of the base 18 of the cylindrical lower box part 6. If the vacuum chamber 10 is evacuated and a vacuum is generated therein via a vacuum generator connected to the vacuum connection 26, the actuator piston 5 moves counter to the spring force in the direction of the base 17 of the box cover 7, owing to the pressure difference in the vacuum chamber 10 and the ambient-pressure chamber 11 which acts on the membrane 9. The adjustment position of the actuator piston 5 can be controlled by changing and setting the partial vacuum in the vacuum chamber 10, an adjustment of the actuator piston 5 being transmitted to the piston rod 2, which is connected to the actuator piston Sin the centre of the base 16 thereof.

On the side of the membrane 9 facing the lower box part 6, a plate-shaped shim plate 29 lies with its flattened side from below against the membrane base 15. The membrane base is thus sandwiched between the base 16 of the actuator piston and the shim plate 29.

On the other side of the piston head 16, which faces in the direction of the base 17 of the box cover 7, there is arranged a further shim plate 30. The piston head 16, the membrane base 15 and the shim plates 29, 30 are provided with a bore 31, through which the one end of the piston rod 2 projects, the head 32 of which is designed such that it holds the membrane base 15, the piston plate or piston head 16 and the shim plates 29, 30 together in the manner of a riveted connection. In such case, the end of the piston rod 2 which is connected to the piston head 16 projects through an opening 33 in the base 18 of the lower box part 6. The opening 33 is arranged in the centre of a recess 34 in the base 18 of the lower box part 6, the shim plate 29 being supported on the recess 34 which stands out from the base 18 of the lower box part 6. The piston rod 2 is guided by an insert 35 which is inserted into the recess 34 in the lower box part 6 from outside the control box I and which a sealing ring 36 seals off from the lower box part 6.

The operating principle of the control box I and the position sensor 4 for detecting the position of the actuator piston 5 for a turbocharger with variable geometry will now be described with reference to Fig. 3.

The actuating element 3 of a turbocharger with variable geometry or of a exhaust gas recirculation valve moves in rotary manner on a circular path I, in order to set the angle of attack of a rotor blade (not shown). Owing to this circular movement I, the piston rod 2 of the control box 1, which acts on the actuating element 3 and moves it, has to perform a roto-translational movement II, i.e. be both displaced and turned. The actuator piston 5 is connected rigidly to the one end of the piston rod 2 and thus continues the roto-translational movement in the interior of the control box 1, so that the actuator piston 5 is not displaced linearly, but rather is tilted relative to the actuator housing 8 and executes a wobbling movement in the interior of the actuator housing 8.

This wobbling movement is converted by the transmission device 37 according to the invention, which comprises a transmission element 38 and a compensating joint 39 attached to the base 16 of the actuator piston 5, into a purely linear displacement III of the transmission element 38 in the adjustment direction V. In order to convert the roto-translational movement II into a linear displacement III, the compensating joint 39 arranged on the base 18 of the actuator piston 5 mounts the transmission element 38 in a rotatable manner about at least two axes of rotation R extending at right-angles to one another and at right-angles to the adjustment direction V. Furthermore, part of the compensating joint 39 is attached displaceably to the actuator piston 5. In the embodiment illustrated, the displaceable arrangement has an effect such that the transmission element 38 can be displaced on the base or head 16 of the actuator piston 5 along the sliding axes G, which extend at right-angles to one another and at right-angles to the adjustment axis V, relative to the actuator base 16.

In this manner, the compensating joint 39, in its function as a rotary joint, compensates for the tilting of the actuator piston 5 out of its original position, in which the piston base 16 extends substantially parallel to the base 17 of the box cover 7 or of the base 18 of the lower box part 6. The deflection of the centre of the piston base 16, on which the one end of the piston rod 2 is arranged, away from the centre line M in turn compensates for the compensating joint 39 by means of the displaceable arrangement of one of its part on the actuator piston 5.

Thus the transmission device 37 according to the invention compensates for the tilting and deflection upon the wobbling movement of the actuator piston 5 in the interior of the actuator box 8 and ensures that each actuating position of the actuator piston 5 of the control box 1 corresponds exactly to a position of the transmission element 38 in the adjustment direction V. The transmission device 37 according to the invention according to a first embodiment is shown in Figures 4 to 9. Even if the transmission device 37 according to the invention is explained in greater detail below by way of example with regard to a position sensor 4, in particular a position sensor 4 for detecting the position of an actuator piston 5 of a control box I for an exhaust gas recirculation valve or a turbocharger with variable geometry, the transmission device 37 can also be used in other devices in which non-linear guidance has to be compensated for and converted into a linear displacement, for example in regulating the ride height of vehicles.

The transmission device 37 comprises a transmission element 38 with at least one indicator 40, by which a position signal detectable by a sensor, for example the position sensor 4, is generated, and a compensating joint 39. In the embodiment shown, the compensating joint 39 is for example arranged on the base 16 of an actuator piston 5 and the indicator is for example a permanent magnet which produces a magnetic field by which the position of the indicator 40 in the adjustment direction is recognised by the position sensor 4. However, a visual marking can also be used as an indicator 40 on the transmission element 38.

The transmission element 38 in the embodiment illustrated is in the form of a transmission rod 38', on the sensor end 41 of which the magnet 40' is arranged. At least the region of the sensor end 41 of the transmission rod 38' with the magnet 40' in the mounted state, which is shown in Fig. 2 by way of example for a position sensor 4 of a control box 1, is arranged linearly displaceably along the adjustment direction V, which coincides with the centre line M of the control box I or of the position sensor 4, in a receptacle 42 of the sensor housing 22.

The receptacle 42 is formed substantially as a guide channel 43, the longitudinal axis of which corresponds substantially to the centre line M of the position sensor or of the control box 1, and which in the assembled state shown in Fig. 2 is oriented substantially in alignment with the bore 31 and the opening 33. The transmission rod 38' has a substantially constant external diameter d1.

On the sensor end 41, the transmission rod 38' is provided with a blind bore 44 on its end face. The magnet 40' is made cylindrical, with an external diameter which corresponds to the external diameter d1 of the transmission rod 38' and the cylinder bore 45 of which corresponds substantially to the blind bore 44. The magnet 40' is connected to the sensor end 41 of the transmission rod 38' via a closing cap 46. The closing cap 46 has a threaded rod 47 which in the mounted state projects through the cylinder bore 45 of the magnet 40' and is screw-connected in the blind bore 44 to the sensor end 41 of the transmission rod 38'. The cylindrical magnet 40' is screwed tightly between the closing cap 46 and the sensor end 41 of the transmission rod 38' by means of the screw connection. Overall, the magnet 40' in the assembled state represents a continuation of the transmission rod 38' which is closed off in the conical or semicircular head 48 of the closing cap 46.

On the fastening end 49 of the transmission element 38, which lies opposite the sensor end 41, in the embodiment illustrated, the transmission rod 38' is provided with a part of the compensating joint, in the embodiment illustrated, a joint head 50, which for example is in the form of a ball element 51. The external diameter d4 of the ball element 51 is greater than the external diameter d1 of the transmission rod 38'. At the point at which the transmission rod 38' merges into the ball element 50, the ball element 51 is flattened off and has a shoulder 52 facing at right-angles to the longitudinal axis of the transmission rod 38', out of which shoulder the transmission rod 38' projects.

The joint head 50 together with a shell 53 forming a joint socket, which is shown in Fig. 5, forms a ball-and-socket joint 54 which effects the rotatable mounting of the transmission element 38' in the embodiment illustrated.

The shell 53, as shown in Figs. 2, 6 and 7, can be connected undetachably to the joint head 50, so that the transmission element 38 and the shell 53 can be mounted as a unit which can be handled in one piece, as shown in Fig. 6.

The shell 53 is substantially of annular or cylindrical form, and is formed by a shell body 55 and a shell lid 56. Both the shell body 55 and the shell lid 56 are both in annular form, and complete one another in the closed state, in which the shell lid 56 lies with its lid underside 57 against the upper side 58 of the shell body 55, to form a cylindrical component with a substantially constant shell casing or outer surface 58 which is formed by the casing or outer surface 59 of the shell lid 56 and the casing or outer surface 60 of the shell body 55.

On the underside 57 of the lid there are arranged two fastening pins 62 located diametrically opposite one another and on opposite sides of a lid opening 61. The pins project out of the underside 57 of the lid substantially at right-angles thereto.

The shell body 55 has fastening openings 63 which correspond to the fastening pins 62, into which openings the fastening pins 62 can be pressed and thus the shell body 55 can be connected to the shell lid 56. The shell lid 56 can be swung away from the shell body 55 via a hinge 64 which connects the shell body 55 and shell lid 56 undetachably together. The hinge 64 is substantially a flexible connecting web which extends from the outer edge of the shell body 55, where the surface 60 merges into the upper side 58 of the casing with the edge of the shell lid 56, where the underside 57 of the lid abuts the lid surface 59.

Both the shell body 55 and the shell lid 56 are provided with a central receptacle or recess or 66 respectively, which in the closed state of the shell 53 complement one another to form the seat 67 for the joint head 50. In the closed state, the seat 67 surrounds a substantially spherical region which is adapted to the shape of the ball element 51 of the transmission element 38 which is to be received. The receptacles 65 and 66 are each formed in the manner of a shell.

For mounting the ball-and-socket joint 54, the shell lid 56 is pushed over the sensor end 41 of the transmission rod 38' such that the underside 57 of the lid points downwards, i.e. in the direction of the ball element 51. As soon as the ball element 51 comes to lie in the shell-shaped receptacle 66 of the shell lid 65, the shell 53 is closed by connecting the shell body and shell lid 56 together. In this mounted position, which can be seen in Fig. 6 and Fig. 2, the joint element 50 is arranged in the seat 67 of the shell 53, and makes it possible for the transmission rod 38', which is arranged outside the shell 53, to be rotatably mounted relative to the shell 53 about three axes of rotation which are at right-angles to one another.

The shell lid 56 is provided on its upper side 68 with a tilting stop 69, which is formed by a border 69'. The border 69' projects from the upper side 68 of the lid and surrounds the lid opening 61, through which the fastening end 43 of the fastening element 38 extends.

The border 69' has firstly the function of a tilting stop 69, which limits the tilting of the transmission element 38 relative to the shell 53 to a maximum angle of inclination a. The transmission rod 38' can only be tilted until the fastening end 49 is stopped against the border 69' on the upper side 68 of the shell lid 56.

The compensating joint 39, in the embodiment shown, given by way of example, is arranged on the upper side of the base 16 of the actuator piston 5 which faces in the direction of the base 17 of the box cover 7, such that the shell 53 is attached to the base 16; the tilting stop 69 consequently also limits the tilting of the transmission element 38 relative to the base 16 of the actuator piston 5. The tilting stop 69 of the compensating joint 39 therefore limits the maximum possible tilting of the transmission element 38 relative to the non-linearly guided component, actuator or sensor element on which the compensating joint is arranged or attached, and thus determines the maximum possible tilting which can be compensated for by the transmission device 37 according to the invention.

Thus the desired maximum angle of inclination a of the ball-and-socket joint 54 can be achieved by means of corresponding dimensioning of the external diameter of the transmission rod 38' and/or the configuration of the shell lid 56, in particular the diameter d3 of the lid opening 61 and the border 69' thereof. The maximum angle of inclination a must in each case be sufficiently large to compensate for the maximum possible tilting of the piston head 16 relative to the base 17 and 18 on the underside of the box cover 7 or lower box part 6 during operation of the control box 1.

Finally, the shell body 55 has on its underside 70 a circular cavity 71, SO that the underside of the shell body 55 in the mounted state merely lies on its edge region. In the embodiment shown in Fig. 2, the shell body 55 lies on the upper side of the piston head 16, the shim plate 30 and also the rivet head 32 being arranged at the fixed end of the piston rod 2 in the cavity 71.

The compensating joint 39 has, in addition to the ball-and-socket joint 54, a slip joint 72 with a compensating slide 53' and a guide means 73, which joint ensures that a part of the compensating joint 39, in the embodiment illustrated for example the shell 53, is attached displaceably to the actuator piston 5.

The slip joint 72, which can also be referred to a sliding bearing, in the embodiment illustrated is formed by the shell 53 as movable joint element and a guide means 73 which can be fixed in stationary manner with the upper side of the actuator, in the embodiment illustrated with the base 16 of the actuator piston 5.

The guide means 73 is in the form of a guide sleeve 73' which is substantially in the shape of a pot, the sleeve base 74 having a circular opening 75, the inner wall 76' of which in the mounted state, as is shown in Fig. 2, forms a displacement stop 76, against which the border 69' of the shell lid 56 abuts after a maximum displacement path D1, relative to the centre line M. The upper edge of the guide sleeve 73' is provided with a fastening flange 77 which forms an outward collar around this edge. This flange 77, in the mounted state shown in Fig. 2, comes to lie against the base 16 of the upper side of the actuator piston 5 and forms the piston-side seat for the spring 28. In this manner, the guide sleeve 73' is pressed by the spring 28 securely on to the base 16 of the actuator piston 5, which attaches the compensating joint 39 of the transmission device 37 to the base 16 of the actuator piston 5.

The height h of the shell 53 from the underside 70 of the shell body 55 to the upper side 68 of the shell lid 56 corresponds substantially to the internal height H of the guide sleeve 73', measured from the face of the sleeve base 74 which faces into the interior of the pot-shaped guide sleeve 73' to the upper side of the fastening flange 77, which in the fastened state lies against the base 16 of the actuator piston 5. The height h of the shell 53 is however somewhat less than the internal height H of the fastening flange, so that displacement of the shell 53 as compensating slide 53' in the guide sleeve 73' slipped over this shell 53 on the base 16 of the actuator piston 5 parallel to the piston head 16 is possible.

Fig. 2 shows a control box I with mounted position sensor 4. In this mounted state, the sensor housing or body 22 is mounted by means of the fastening collar 23 on the fastening ring 20 of the box cover 7. The guide channel 43 of the sensor body 22 extends in the mounted state substantially along the centre line M of the control box 1.

In this mounted state, the sensor end 41 of the transmission rod 38' with the magnet 40' and the closing cap 46 is received in the guide channel 43, and can be displaced along the adjustment axis V. In this case, the transmission device 37 according to the invention translates the roto-translational movement II of the actuator piston 5 into the linear displacement III of the transmission element 38 along the adjustment axis V. The magnet 40' generates a position signal representative of its position in the adjustment direction, which signal is detected and emitted by a sensor element 78. In the embodiment illustrated, the sensor element 78 is for example a magnetic-field sensor, such as a Hall sensor.

As can be seen in Fig. 2, the sensor element 78 is arranged in a chamber 79 of the housing body 22. The chamber 79 is formed in the region of the housing body 22 which lies outside the actuator housing 8 in the mounted state, and an externally accessible opening of the chamber 79 is closed by a cover means 80.

The output signal of the sensor element 78 can be transmitted to a control element (not shown), which control element regulates the vacuum generator (not shown) which generates the partial vacuum in the vacuum chamber 10 and controls the control box 1. In this manner, a closed control loop for the control box I is made possible.

The control box I according to the invention with the transmission device 37 according to the invention and a special configuration of the sensor housing 22 permits blind assembly of the control box I and position sensor 4, as is explained in greater detail below with reference to Figs. 8 and 9.

It should be pointed out that the control box I is not completely shown in Fig. 8 for clarity, but the base 17 of the box cover 7 with the fastening ring 20 has been omitted.

Due to the border 69' on the upper side 68 of the shell lid 56, which forms a displacement stop 69, the maximum angle of inclination ci of the transmission element 38 relative to the shell 53 or to the base 20 of the actuator piston 5 is limited.

Furthermore, the border 69' in co-operation with the inner wall 76' of the circular opening 75 in the sleeve base 74 of the guide sleeve 73' represents a displacement stop 76 which limits the displacement of the transmission element 38 or of the compensating slide 53' formed by the shell 53 in the guide means 73 to a maximum displacement path D1. The border 69' therefore ensures that the transmission rod 38' in the pre-mounting state which is shown in Fig. 8 and in which the position sensor 4 is not yet mounted on the control box 1, is nevertheless held relatively centrally and upright, which facilitates the mounting of the position sensor 4.

Upon mounting the position sensor 4 and the control box I, the sensor body 22 is introduced substantially along the centre line M into the opening 19 in the base 17 of the box cover 7, at least partially, until the fastening collar 23 comes to lie in the fastening ring and is fastened by crimping the tongues 21. Upon mounting the position sensor 4, the head 48 of the closing cap 46 hits a ramp structure 81 which is formed in the region of the introduction opening 82 of the guide channel 43 on the sensor housing 22. The ramp structure 81 is arranged around the introduction opening 82 and forms a guide incline 83 extending in the direction of the introduction opening 82, against which incline the closing cap 46 hits upon mounting and along which the cap 46 is guided to the introduction opening 82.

In order to achieve proper guidance, i.e. in order to guide the closing cap 46 of the transmission element 38 in the direction of the introduction opening 82 upon meeting the ramp structure 81, the inclination f3 of the guide incline 83, relative to the introduction opening 82, must be smaller than the maximum angle of inclination a permitted by the tilting stop 69. Only if a < f3 will the closing cap 46 meet the guide incline 83 of the ramp structure 81 at an acute angle which points in the direction of the introduction opening 82, so that the transmission element 38 is guided along the guide incline 83 to the introduction opening 82 and not guided away therefrom.

Fig. 9 shows a preferred embodiment of the ramp structure 81, which is formed by a plurality of guide elements 84, in the embodiment illustrated guide ribs 84', which, viewed along the centre line M, are arranged with their guide inclines 83 in a star-shape around the

introduction opening 82.

The maximum distance d5 between adjacent guide ribs 84' is less than the external diameter d1 of the transmission rod 38', which ensures that the transmission rod 38' meets the guide inclines 83 of the guide elements 84 and does not end up in the gaps between the guide ribs 84'. The external diameter d1 of the transmission rod 38' corresponds substantially to, i.e. is only slightly less than, the internal diameter d2 of the guide channel 43, which achieves an exclusively linear displacement in the adjustment direction V of the transmission element 38 in the guide channel 43.

Furthermore, the lateral distance D2 from the centre line M of the introduction opening 82 to the outer edge 85 of the ramp structure 81 is greater than the maximum possible lateral deflection Dmax of the transmission element 38 relative to the centred arrangement thereof, i.e. in the embodiment illustrated relative to the case in which the longitudinal axis L of the transmission element 38 coincides with the centre line M. In that case, the maximum possible lateral deflection Dmax in the embodiment illustrated, in which a rotary joint 54 with at least two degrees of freedom is coupled to a slip joint 72 with two degrees of freedom in the compensating joint 39, corresponds to the maximum displacement path Dl of the slip joint 72, measured from the centred position of the shell 53 to the stop of the border 69' on the inner wall 76' of the circular opening 75, plus the maximum deflection D3 which is possible due to the tilting of the transmission element 38 in the ball-and-socket joint. This corresponds substantially to D3 = sin a x I, I being the length of the transmission element, measured from the tip of the head 48 of the closing cap 46 to the point of rotation 86 of the ball element 50.

If the sum D1 + D3 ( Dmax) is smaller than the lateral distance D2 of the ramp structure 81, it is ensured that, even at maximum possible deflection Dmax of the transmission element 38 out of the centre line M, the tip of the closing cap 46 always hits the ramp structure 81.

Fig. 10 finally shows a perspective sectional view through a further embodiment of the transmission device 37 according to the invention; its differences from the first embodiment shown in Fig. 2 will merely be discussed briefly below.

The same reference numerals will be used below for components, the function and/or construction of which is similar or identical to components of the first embodiment. For clarity, the spring 28 is omitted in Fig. 10.

The transmission element 38 of the second embodiment corresponds substantially to the transmission element 38 of the first embodiment, but instead of the ball element 51 of the first embodiment a joint disc 86 is arranged as joint element 50 on the fastening end 49 of the transmission rod 38'.

The width of the joint disc 86, viewed in the direction of the longitudinal axis L of the transmission rod 38', is greater than the external diameter d1 of the transmission rod 38', SO that the transmission element 38 of the second embodiment is substantially nail-shaped, the joint disc 86 forming the nail head.

The compensating joint 39 of the second embodiment comprises, in addition to the joint disc 86 arranged on the transmission element 38, a ring clamp 87 which takes over the function of the shell 53 and the guide sleeve 73 of the first embodiment.

The ring clamp 87 in the embodiment illustrated is formed by two clamp parts 88 and 89, of which the first clamp part 88 corresponds in its shape substantially to the guide sleeve of the first embodiment and likewise has a fastening flange 77 which forms a seat for one end of the spring 28 (not shown in Fig. 10), on which the ring clamp 87 of the spring 28 presses on the base 16 of the actuator piston 5 and is arranged thereon.

The second clamp part 89 is substantially disc-shaped with a circular opening 75', the outer disc edge 90 being bent over and assuming a structure adapted to the interior of the substantially pot-shaped first clamp part 88.

In the region of the circular openings 75, 75', the first 88 and the second 89 clamp parts complete each other to form an annular receptacle 91 for the joint disc 86, which receptacle forms the guide means 73 for displacing the joint disc 86 on the actuator piston 5.

In the mounted state, which is shown in Fig. 10, the inner region, surrounding the circular opening 75, of the first clamp part 88, which forms the receptacle 91, lies against the side of the longitudinal disc 86 out of which the transmission rod 38' projects. On the outside of the joint disc 86 which faces in the direction of the base 16 of the actuator piston 5 is arranged on the region of the second clamp part 89 forming the receptacle 91 Thus the first clamp part 88 and the second clamp part 89 of the ring clamp 87 mount the joint disc 86 in the annular receptacle 91, which is formed by the ring terminal 87. Since the clamp parts 88, 89 of the ring terminal 87, which define the receptacle 91, can be deflected in the direction of the base 17 of the box cover 7 and of the base 18 of the lower box part 6, the ring clamp 87 and the joint disc 86 form a rotary joint which permits rotation of the transmission element about at least two axes of rotation extending at right-angles to one another and to the adjustment direction V. Furthermore, the diameter d6 of the receptacle 91 of the ring terminal 87 is wider than the external diameter d4 of the joint disc 86, and the circular opening 75 of that of the first clamping part is greater than the external diameter d1 of the transmission rod 38'. This makes it possible, in the second embodiment, for the transmission element 38 with its joint disc 86 as compensating slide 53' in the ring terminal 87, which is oriented parallel to the base 16 of the actuator piston 5, to be arranged displaceably on the actuator piston 5, by means of which deflection of the actuator piston 5 out of the centre line M of the control box 1 can be compensated.

In the present application, the transmission device 37 according to the invention and the position sensor 4 according to the invention which has this transmission device 37 are described by way of example with regard to the detection of the position of an actuator piston 5 of a control box 1 for an exhaust gas recirculation valve or a turbocharger with variable geometry. However, these devices according to the invention may also be used in other devices or sensors or actuators in which a non-linear movement is to be compensated and converted into a linear displacement, for example in regulating the ride height of vehicles.

Claims

Claims 1. A transmission device (37) for a position sensor (4) for detecting the position of an actuator piston (5) of a control box (1) for an exhaust gas recirculation valve or a turbocharger with variable geometry, comprising a transmission element (38) which is linearly displaceable in an adjustment direction (V), by means of which element a position signal which is representative of its position and can be detected by the position sensor (4) can be generated, and with a compensating joint (39), by means of which a relative rotation between the transmission element (38) and actuator piston (5) about at least two axes of rotation extending at right-angles to one another and at right-angles to the adjustment direction (V) can be compensated for, characterised in that a part of the compensating joint (39) forms a compensating slide (53') which is designed to be able to be attached displaceably to the actuator piston (5).
2. A transmission device (37) according to Claim 1, characterised in that the compensating joint (39) has a ball-and-socket joint (54').
3. A transmission device (37) according to Claim 1 or 2, characterised in that a shell (53) of the compensating joint (39) forms the compensating slide (53').
4. A transmission device (37) according to Claim 3, characterised in that the shell (53) of the compensating joint (39) has a shell body (55) and a shell lid (56) which can be connected to the shell body (55) with an opening (61), an internal width d3 of the opening (61) being less than an external dimension d4 of a joint head (50) which can be received in the shell (53).
5. A transmission device (37) according to Claim 4, characterised in that the shell body (55) and the shell lid (56) are undetachably connected together.
6. A transmission device (37) according to claim 5 characterised in that the shell body (55) and the shell lid (56) are undetachably connected together via a hinge (64).
7. A transmission device (37) according to one of Claims I to 6, characterised in that the compensating joint (39) has a tilting stop (69) which limits the tilting of the transmission element (38) relative to the actuator piston (5) to a maximum angle of inclination a.
8. A transmission device (37) according to one of Claims I to 7, characterised in that the compensating joint (39) has a displacement stop (76) which limits the displacement of the compensating slide (53') on the actuator piston (5).
9. A transmission device (37) according to one of Claims I to 8, characterised in that the transmission element (38) is formed as a transmission rod (38'), on one end (41) of which at least one indicator (40) by means of which the position signal can be generated and on the other end (49) of which a part of the compensating joint (39) is arranged.
10. A position sensor for detecting the position of an actuator piston (5) of a control box (1) for an exhaust gas recirculation valve or a turbocharger with variable geometry, comprising a transmission device (37) according to one of Claims I to 9, a sensor housing (22) with a receptacle (42) for guiding the transmission element (38), and at least one sensor element (78) for emitting a position signal representative of the position of the transmission element (38).
11. A position sensor according to Claim 10, characterised in that the receptacle (42) has an introduction opening (82) which is surrounded by a ramp structure (81) with a guide incline (83) extending in the direction of the introduction opening (82).
12. A position sensor according to Claim 11, characterised in that the ramp structure (81) is formed by guide elements (84), the maximum distance D1 between adjacent guide elements (84) being smaller than the cross-sectional width d1 of the section of the transmission element (38) which is introduced into the receptacle (42).
13. A position sensor according to Claim 11 or 12, characterised in that the compensating joint (39) has a tilting stop (69) which limits the tilting of the transmission element (38) relative to the actuator piston (5) to a maximum angle of inclination a and the maximum angle of inclination a permitted by the tilting stop (69) is smaller than the inclination f3 of the guide incline (83) relative to the introduction opening (82).
14. A position sensor according to one of Claims II to 13, characterised in that the lateral distance from the centre line M of the introduction opening (82) to the outer edge (85) of the ramp structure (81) is greater than the maximum possible lateral deflection Dmax of the transmission element (38).
15. An assembly of a control box (I) for an exhaust gas recirculation valve or a turbocharger with variable geometry, comprising a control box (1) with an adjustable actuator piston (5) for setting the exhaust gas recirculation valve or the turbocharger with variable geometry, and a position sensor (4) according to one of Claims 10 to 14, wherein, in the assembled state of the assembly, the transmission element (38) is arranged at least in sections in the receptacle (42) of the sensor housing (22) and the part of the compensating joint (39) which forms the compensating slide (53') is attached displaceably to the actuator piston (5).
16. A control box (1) for an exhaust gas recirculation valve or a turbocharger with variable geometry, comprising an adjustable actuator piston (5) for setting the exhaust gas recirculation valve or the turbocharger with variable geometry, and a transmission device (37) according to one of Claims I to 9, the part of the compensating joint (39) which forms the compensating slide (53') being attached displaceably to the actuator piston (5).