Angular position sensor for determining an angular position and/or a torque

An angular position sensor may include a housing, and a rotor including a rotor assembly with a rotor latching device. The rotor and the housing are connected by the rotor latching device secured by a retaining ring. The retaining ring can be transferred into a secured position in an axial direction. The retaining ring is integral with the rotor assembly and features at least one retaining element with which the retaining ring secures the connection of rotor and housing. The retaining ring and the rotor latching device each feature corresponding latching elements. The rotor assembly features axial position-securing elements. The latching elements interact such that the retaining ring is secured in an axial direction along the rotary axis relative to the rotor. The axial position-securing elements interact so that the rotor is secured essentially free of play on the housing in an axial direction along the rotary axis.

FIELD OF THE INVENTION

The present invention relates to angular position sensor for determining an angular position and/or of a torque.

BACKGROUND OF THE INVENTION

Numerous embodiments of such angular position sensors are known from the state of the art. For example, DE 10 2012 105 963 A1 discloses an angular position sensor for determining a relative angle setting in relation to a reference position, comprising a housing, at least one rotor that is mounted on a bearing in the housing such that it can rotate and a printed circuit board with electric and/or electronic components and one or several stators matching the number of rotors. Among other things, the known angular position sensor should ensure precise alignment of a first one of the rotors to the stator. This is achieved by a first one of the rotors is latched to the housing without play, where a spring washer is arranged pretensioned on latching arms.

BRIEF SUMMARY OF THE INVENTION

The present invention is based on the task of improving angular position sensor for determining an angular position and/or a torque.

This task is solved by an angular position sensor that is characterized in that the retaining ring is an integral part of the rotor assembly and features at least one retaining element with which the retaining ring in its secured position secures the connection of rotor and housing, and where the retaining ring and the rotor latching device each feature latching elements to each other and the rotor assembly features axial position-securing elements, and where the latching elements interact in the secured position of the retaining ring in such a way that the retaining ring is secured in an axial direction along the rotary axis relative to the rotor, and where the axial position-securing elements interact in the secured position of the retaining ring in such a way that the rotor is secured essentially free of play on the housing in an axial direction along the rotary axis. The term “latching element” should be interpreted broadly in this context and also comprises press-fit elements.

One material advantage of the inventive angular position sensor is in particular the fact that the angular position sensor is improved. For example, the inventive angular position sensor can be manufactured in an easier and more cost-effective manner as the joining of a retaining ring designed as a separate spring washer and the welding of a retaining ring in the form of a holding ring is no longer necessary. Furthermore, the at least one retaining element of the retaining ring in combination with the axial position-securing elements of the rotor assembly ensures firstly a secure connection between the rotor and the housing and secondly securing of the rotor to the housing in a way that is essentially free of play.

One advantageous refinement of the inventive angular position sensor specifies that the housing features a housing latching device corresponding to the rotor latching device of the rotor, where the rotor and the housing are latched to each other by means of the rotor latching device and the housing latching device in the installed position of the rotor and such latching is secured by means of the retaining ring, and where the retaining ring with the retaining element in the secured position grips the rotor latching device in such a way that the latching of rotor and housing is secured. This implements the connection between the rotor on the one side and the housing on the other side using a simple and robust design.

One especially advantageous refinement of the inventive angular position sensor specifies that the retaining ring and the rotor latching device feature torque transmission devices corresponding to each other, where the torque transmission devices are designed in such a way that a torque can be transmitted around the rotary axis by means of the torque transmission devices. In this way, the torque transmission is reliably ensured between the rotor latching device and the retaining ring, i.e. within the rotor assembly of the rotor. In addition, this effectively relieves the latching elements for connecting the rotor latching device and the retaining ring with regard to its mechanical load.

In principle, it is conceivable that the rotor latching device and/or the retaining ring are/is designed as a separate component. One advantageous refinement of the inventive angular position sensor specifies that the rotor latching device and/or the retaining ring are/is designed to be a single-piece with the rotor. This reduces the number of components and thus simplifies stock keeping and logistics. It is, for example, conceivable that the rotor locking device and/or the retaining ring made of plastic and a rotor made of metal are bonded to each other to form one piece using a plastic injection molding process. In this respect, the rotor itself can be designed as one piece or several pieces.

One advantageous refinement of the aforementioned embodiment of the inventive angular position sensor provides that the rotor latching device and/or the retaining ring are/is designed as a plastic part, where the rotor latching device or the retaining ring surrounds the rotor in such a way that in the installed position of the rotor the stator is firstly protected from coming into direct contact with the rotor and secondly a visual inspection of the position of the rotor is made possible. In this way, effective protection especially of the stator from unintended damage by the rotor and at the same time it is possible to check the position of the rotor in a simple manner, using a camera, for example. This is important as with inductive measuring methods the alignment of the rotor relative to the stator play a decisive role in a high-quality measurement using the angular position sensor.

One further advantageous refinement of the inventive angular position sensor specifies that the rotor latching device, the retaining ring and the housing are designed to complement each other in such a way that the connection of the rotor with the housing in the installed position of the rotor can be checked by means of a visual inspection. A correct connection between the rotor and the housing is necessary for the proper functioning of the inventive angular position sensor even under adverse ambient conditions such as vibrations, changes in temperatures and the like. Using the angular position sensor in accordance with this refinement, it is easily possible to check the existence of a correct connection between the rotor and the housing by means of a camera, for example.

One especially advantageous refinement of the inventive angular position sensor specifies that the rotor latching device and/or the retaining ring are/is designed in such a way that the rotor latching device and/or the retaining ring can be manufactured in an injection molding process without the use of sliders. This makes it possible to implement the inventive angular position sensor in an especially easy and cost-effective manner.

Another advantageous refinement of the inventive angular position sensor specifies that the rotor latching device and the retaining ring feature adjusting devices corresponding to each other for automatically aligning the retaining ring relative to the rotor latching device when it is being transferred into its secured position. This simplifies the alignment of the retaining ring relative to the rotor latching device and thus ensures a correct connection between the retaining ring on the one hand and the rotor latching device on the other when transferring the retaining ring into its secured position.

One further advantageous refinement of the inventive angular position sensor specifies that the rotor latching device and/or the retaining ring feature/features lubricant traps filled with a lubricant that are arranged in such a way that movement of the rotor relative to the housing is promoted. This makes it possible to perform a low-wear and thus low-noise rotation of the rotor around the rotary axis.

Furthermore, a further advantageous refinement of the inventive angular position sensor specifies that the latching elements of the retaining ring are designed as locking hooks, the latching elements of the rotor latching device as detent openings and the axial position-securing elements of the rotor assembly as protrusions and/or shoulders arranged on the rotor latching device and on the retaining ring. In this way, it is firstly possible to implement a robust and simply designed connection of the retaining ring with the rotor latching device and at the same time a very compact arrangement of the axial position-securing elements.

An alternative advantageous refinement of the inventive angular position sensor specifies that the latching elements of the retaining ring are designed as press-fit elements, the latching elements of the rotor latching device as press-fit apertures and the axial position-securing elements of the rotor assembly as protrusions and/or shoulders arranged on the rotor latching device and on the retaining ring. This facilitates a very space-saving embodiment of the rotor assembly and thus of the angular position sensor.

A further advantageous refinement of the inventive angular position sensor specifies that the retaining ring is designed as an angular position detection element for determining the angular position, preferentially as an initial gearwheel. This further increases the functionality of the retaining ring. In addition, thus further reduces the number of component and the space needed.

DETAILED DESCRIPTION OF THE INVENTION

A first sample embodiment of the inventive angular position sensor is shown inFIG.1through18and is explained in more detail in the following.

In the present case, the angular position sensor2is an inductive steering-angle sensor and designed for determining an angular position sensor and shown in an exploded drawing inFIG.1. The angular position sensor2comprises a housing4with a housing lower part6and a housing upper part8, a rotor12arranged on the housing4to be rotatable around a rotary axis10and a printed circuit board14with at least one stator (not shown) corresponding to the rotor12, where the rotor12features a rotor assembly16with a rotor latching device18, and where the rotor12and the housing4are connected to each other by means of the rotor latching device18in a mounting position of the rotor12shown inFIGS.4through12and such connection is secured by means of a retaining ring20, where the retaining ring20can be transferred into a secured position shown inFIGS.4through18in an axial direction to the same along the rotary axis10.

The retaining ring20is an integral part of the rotor assembly16and in the present sample embodiment features a total of four retaining elements22with which the retaining ring20in its secured position secures the connection of rotor12and housing4, where the retaining ring20and the rotor latching device18each feature latching elements24,26corresponding to each other and the rotor assembly16features axial position-securing elements28,30, and where the latching elements24,26interact in the secured position of the retaining ring20in such a way that the retaining ring20is secured in an axial direction along the rotary axis10relative to the rotor12, and where the axial position-securing elements28,30interact in the secured position of the retaining ring20in such a way that the rotor12is secured essentially free of play on the housing4in an axial direction along the rotary axis10. In the present sample embodiment, the rotor latching device18and the retaining ring20each feature a total of four latching elements24,26and each a total of four axial position-securing elements28.30. The latching elements24of the retaining ring20are designed as locking hooks, the latching elements26of the rotor latching device18as detent openings and the axial position-securing elements28,30of the rotor assembly16are designed as shoulders30arranged on the rotor latching device18and as protrusions28arranged on the retaining ring20.

Furthermore, the angular position sensor2features an additional rotor32that is designed in a way known to a specialist and arranged on the rest of the angular position sensor2. The two rotors12,32are necessary in order to also determine the torque of a steering shaft (not shown) of a vehicle (likewise not shown) in addition to the angular position; a steering shaft on which the angular position sensor2is arranged. Over and above this, the retaining ring20is designed at the same time as an angular position detection element for determining the angular position, namely as an initial gearwheel. This makes it possible to implement a counter function by means of which, for example, also multiple rotations of the steering shaft can be determined.

To connect the rotor12with housing4, the housing4features a housing latching device34corresponding to the rotor latching device18of the rotor12, where the rotor12and the housing4by means of which the rotor latching device18and the housing latching device34are latched to each other in the installed position of the rotor12. For this purpose, the rotor latching device18features a total of four locking hooks36that engage with a locking shoulder38of the housing latching device34in the mounting position of the rotor12. This latching is secured by means of the retaining ring20, where the retaining ring20with the retaining elements22engages in the rotor latching device18in the secured position in such a way that the latching of rotor12and housing4is secured.

Furthermore, the retaining device22of the retaining ring20and the contours (not shown in more detail) of the rotor latching device18are designed as torque transmission devices corresponding to each other, where the torque transmission devices are designed in such a way that a torque can be transmitted around the rotary axis10by means of the torque transmission device. The rotor latching device18is designed as single-piece part with the rotor12, where the rotor latching device18is designed as a plastic part and surrounds the rotor12in such a way that in the mounting position of the rotor12the stator is firstly protected from coming into direct contact with the rotor12and secondly a visual inspection of the position of the rotor12is made possible. For this, see in particularFIGS.9and13from which the rotor12made of metal injection-molded with the rotor latching device18can be seen. The rotor12features rotor blades13and is not completely surrounded by the rotor latching device18made of plastic on its side facing the stator on the printed circuit board14. However, the rotor latching device18made of plastic protrudes on the sides of the rotor12, namely at the sides of each of the rotor blades13or the rotor12, in the direction of the printed circuit board14over the rotor12, namely its rotor blade13, such that a direct contact of the rotor12with the stator is effectively prevented. At the same time, the correct position of the rotor12can be checked easily by means of a camera or the like, which not be possible if the rotor12, especially its rotor blades13, was fully surrounded by the rotor latching device18made of plastic. The rotor blades13of the rotor12are arranged at a tube-like part17of the rotor12and are designed, for example, as a press-bent component made from one sheet.

The rotor latching device18made of plastic is, for example, designed as an injection molded plastic part that is molded onto rotor12. In this respect, the rotor latching device18in the present sample embodiment is designed in such a way that the rotor latching device18can be manufactured in an injection molding process without the use of sliders. For this, see in particularFIG.2from which it can be seen that production of the rotor latching device18in the aforementioned manner is possible. For example, a three-part injection molding tool can be used for this purpose in which a part forms the detent openings26in the rotor latching device18visible fromFIG.2and arranged behind the locking hooks36during the injection molding process. This part can be extended first such that the locking hooks36can expand into the space formed by the same when removing the rotor12with the rotor latching device18molded onto it.

In a similar way, in the present sample embodiment, it is also possible to check the connection of the rotor12with the housing4in the mounting position of the rotor12by means of a visual inspection, for example by means of a camera or the like. For this purpose, the rotor latching device18, the retaining ring10and the housing4are designed to be coordinated with each other. To this end, see in particularFIGS.9and10from which it can be seen that the aforementioned visual inspection of the correct connection of the rotor12with the housing4, namely correct latching of the locking hooks36of the rotor latching device18with the locking shoulder38of the housing latching device34, is made possible in the present sample embodiment.

In order to ensure correct alignment of the retaining ring20relative to the rotor latching device18and thus to the rotor12when transferring the retaining ring20into its secured position, the rotor latching device18and the retaining ring20feature adjusting devices40,42corresponding to each other for automatically aligning the retaining ring20relative to the rotor latching device18when it is being transferred into its secured position. For this purpose, the retaining ring20features a total of four fork-shaped adjusting devices40and the retaining ring a total of four strut-shaped adjusting devices42. In this context, see in particularFIGS.3and16.

How the inventive angular position sensor according to the present sample embodiment is assembled is explained in more detail in the following and on the basis ofFIGS.1through18.

Initially, the angular position sensor2is in a non-installed position of the rotor12, as can be seen fromFIG.1. The individual parts of the angular position sensor2are then connected to each other in the sequence as shown inFIG.1. When doing so, the rotor2with the rotor latching device molded to it18is connected to the housing4. For this purpose, the locking hooks36of the rotor latching device18caused to engage with the locking shoulder38of the housing latching device34of the housing4, namely latched to each other. Then the retaining ring20is connected with the rotor latching device18. In doing so, the retaining ring20is transferred into its secured position, where the locking hooks24of the retaining ring20engage with the detent openings26of the rotor latching device18and latch with the rotor latching device18. In the secured position of the retaining ring20, the retaining elements22of the retaining ring20grip the back of the locking hooks36of the rotor latching device18such that the locking hooks36are secured in their position and thus also the aforementioned latching of the rotor12with the housing4is secured. At the same time, the axial position-securing elements28,30of the retaining ring20and the rotor latching device18ensure that the rotor12is secured essentially free of play on the housing4in an axial direction along the rotary axis10.

One material advantage of the inventive angular position sensor according to the present embodiment is in particular the fact that the angular position sensor2can be manufactured in an easy and cost-effective manner as the joining of a retaining ring designed as a separate spring washer and the welding of a retaining ring in the form of a holding ring is no longer necessary. Furthermore, the at least one retaining element22of the retaining ring20in combination with the axial position-securing elements28,30of the rotor assembly16ensures firstly a secure connection between the rotor12and the housing4and secondly securing of the rotor12to the housing in a way that is essentially free of play4.

FIGS.19a-c,20a-cand21a-ceach show a further sample embodiment of the inventive angular position sensor. These further sample embodiments have been explained in the following only to the extent that they deviate from the sample embodiment mentioned above in each case. Otherwise, reference is made to the statements on the preceding sample embodiments. Identical and functionally identical components have the same reference signs.

FIGS.19athrough19cshow a second sample embodiment of the inventive angular position sensor.FIG.19ashows a perspective view,FIG.19ba side section along the reference line A-A inFIG.19candFIG.19ca top view. The angular position sensor2according to this sample embodiment differs from the angular position sensor2according to the first sample embodiment in that the rotor blades of the rotor12are not partially surrounded by the rotor latching device18but by the retaining ring20of the rotor assembly16, for example in the manner described above. Over and above this, the rotor latching device18is permanently connected to the tube-like part17of the rotor12. For example, the rotor latching device18made of plastic is molded in a similar way to the above to the tube-like part17of the rotor12. The locking hooks24of the retaining ring20point in the direction of the rotary axis10, which simplifies the manufacture of the retaining ring20, for example as an injection molded plastic part. In contrast to the first sample embodiment, the locking hooks36of the rotor latching device18are, instead of the axial position-securing elements30according to the first sample embodiment, designed to be at the same time axial position-securing elements of the rotor latching device18. These axial position-securing elements36interact in the manner already described above with the corresponding axial position-securing elements30of the rotor latching device18. This means that, unlike with the first sample embodiment, both axial position-securing elements36,30are arranged on the rotor latching device18.

FIGS.20athrough20cshow a third sample embodiment of the inventive angular position sensor.FIG.20ashows a perspective view,FIG.20ba side section along the reference line B-B inFIG.20candFIG.20ca top view. The third sample embodiment essentially corresponds to the second sample embodiment such that reference can be made to a large extent to the above statements on the second sample embodiment. In contrast to the second sample embodiment, the locking hooks24of the retaining ring20of the angular position sensor2according to the third sample embodiment point away from the rotary axis10.

FIGS.21athrough21cshow a fourth sample embodiment of the inventive angular position sensor.FIG.21ashows a perspective view,FIG.21ba side section along the reference line C-C inFIG.21candFIG.21ca top view. The angular position sensor2according to the fourth sample embodiment differs from the aforementioned sample embodiment specifically in that the latching elements24of the retaining ring20are designed as press-fit elements and the latching elements26of the rotor latching device18as press-fit apertures. Differing from the preceding sample embodiment, a surface of the retaining ring20visible inFIGS.21aand21cis designed, instead of the axial position-securing elements28according to the first sample embodiment, to be at the same time an axial position-securing element28. This axial position-securing element28interacts in the manner already described above with the corresponding axial position-securing elements30of the rotor latching device18. Furthermore, the rotor latching device18features lubricant traps44filled with a lubricant (not shown) that are arranged in such a way that movement of the rotor12relative to the housing4is promoted.

The invention is not limited to the present sample embodiments. For example, it is conceivable that the sample embodiments explained can be combined with each other in parts. Furthermore, the inventive angular position sensor can be advantageously deployed for a large number of differing applications. Over and above this, it is conceivable that the retaining ring and the rotor latching device feature torque transmission devices corresponding to each other that are designed to be separate from other elements of the retaining ring or the rotor latching device, for example separate from latching elements such as locking hooks or the like.

LIST OF REFERENCE NUMBERS

2Angular position sensor4Housing6Housing lower part8Housing upper part10Rotary axis12Rotor13Rotor blade of the rotor1214Printed circuit board16Rotor assembly17Tube-like part of the rotor1218Rotor latching device20Retaining ring22Retaining elements24Latching elements of the retaining ring2026Latching element of the rotor latching device1828Axial position-securing elements of the retaining ring2030Axial position securing elements of the rotor latching device1832Additional rotor34Housing latching device36Latching locking hooks of the rotor latching device1838Locking shoulder of the housing latching device3440Fork-shaped adjusting devices of the retaining ring2042Strut-shaped adjusting devices of the rotor latching device1844Lubricant traps of the rotor latching device18