Patent Description:
Such sensor devices often comprise at least one sender member for emitting a magnetic field and at least two receiving members for receiving the magnetic field.

A disadvantage of the prior art sensor devices is that they are often imprecise.

In order to provide a solution that gives a higher precision each of the at least two receiving members can comprise two conductors that together delimit at least two surrounded areas, wherein each of the surrounded areas tapers in and against a circumferential direction at its ends. Such a configuration avoids artifacts and thus allows a more precise measurement.

<CIT> and <CIT> show inductive rotation sensors with a sender member and one or more receiving members. <CIT> discloses inductive position sensors with a sender member and at least one receiving member having a periodic shape.

The object of the invention is to provide a solution that compensates inhomogeneities in the magnetic field.

According to the invention, this is achieved, when at least one of the surrounded area is a non-convex surrounded area.

The solution according to the invention can further be improved by the following further developments and advantageous embodiments, which are independent of each other and can be combined arbitrarily, as desired.

The term delimit can here be understood as circumscribe, surround and/or substantially enclose. The conductors do not have to be entirely closed around the surrounded areas. They can have small gaps for example in a contact section in which the conductors can be contacted.

The surrounded areas can be planar or substantially planar to achieve a compact configuration. The surrounded areas can be arranged one behind the other in the circumferential direction. This can help to save space.

Each of the surrounded areas tapers in and against the circumferential direction. That means that each of the surrounded areas tapers in one direction and in the opposite direction and not just in one of the two directions. Each of the surrounded areas can expand in the middle. The middle can be the widest part, the width being measured in a radial direction pointing away from the axis. End sections of the surrounded areas at circumferential ends can have a wedge-shape, in particular with an angled or sharp tip.

The two conductors can form two loops delimiting or surrounding the surrounded areas.

The surrounded areas can each expand and contract in a circumferential direction about the axis of rotation.

The other surrounded areas can be convex areas each expanding and contracting in a circumferential direction about the axis of rotation. In an advantageous development, each of the two surrounded areas is eye-shaped. The surrounded areas can be generally oval and/or lentil-shaped.

In order to further improve the precision, the first and the last of the surrounded areas in the circumferential direction can expand and contract.

In order to further improve the precision, the first and the last of the surrounded areas in the circumferential direction can taper in and against a circumferential direction at their ends.

The circumferential direction can run around the axis.

Two neighboring surrounded areas can be separated from each other by a crossing of the two conductors. The two conductors can be partially located on different levels in order to avoid unwanted contacting. In particular in the area of the crossing, the two conductors can be arranged on two levels. The levels can for example be separated by insulating layers or the conductors can be arranged on a front and a back side of a PCB.

Each of the two conductors can have an elongated shape that is sinusoidal. Each of the two conductors can have an elongated shape that is spatially periodic, i.e. has a pattern that repeats itself in the circumferential direction. Such configurations can allow an easy processing of the data.

The conductor can have the shape of a path or a wire.

In an advantageous embodiment, the at least two receiving members have an identical shape and are shifted by a quarter of a period to each other along the circumferential direction. This can allow an easy determination of the angle. The quarter of the period is a mechanical spacing. It can in particular correspond to approximately half a length of a surrounded area. Electrically, the two receiving members can be shifted by Pi/<NUM> or <NUM> degrees.

The two conductors can be substantially symmetrical or mirror symmetrical to each other with respect to a cylindrical circumferential surface.

In a further advantageous embodiment, the sections of the two conductors that enclose the surrounded areas comprise mainly or only curved sections. This can further improve the signal quality. In particular, no straight sections may be present in this area. Such straight sections can however be present in other parts of the conductors. For example, parts of the conductors that do not surround the surrounded areas and/or do not bound/limit the surrounded areas in particular in the radial direction but lead towards the surrounded areas and are used for contacting, e.g. end in a terminal or solder part, can comprise straight sections.

In a further advantageous embodiment, sections of the two conductors that enclose the surrounded areas comprise straight sections. This can make the production easier.

The two conductors can comprise no straight sections running in a radial direction. This can again avoid the occurrence of artifacts and thus improve the precision. The radial direction can be a direction pointing away from the axis of rotation. It can be perpendicular to the axis.

The sender member can comprise a coil in order to generate the magnetic field. In order to save space, the coil can be planar. In particular, the coil can be a spiral coil.

In a space-saving configuration, the sender member surrounds the receiving members.

Advantageously, at least on one side, preferably on both sides, a distance between the sender member and the receiving members along a circumferential direction is less than ¼ of the period. Preferably, this distance is less than <NUM>/<NUM> of the period. This can help to save space.

In a further advantageous development, at least on one side, preferably on both sides, a distance between the sender member and the receiving members along a circumferential direction is less than ¼ of the length of the sender member along the circumferential direction. Preferably, this distance is less than <NUM>/<NUM> of the length of the sender member along the circumferential direction.

Similarly, a distance between the sender member and the receiving members along a circumferential direction can be less than ¼ of the length of the receiving member along the circumferential direction. Preferably, this distance is less than <NUM>/<NUM> of the length of the receiving member along the circumferential direction.

The distance can moreover be less than ½ a length of the surrounded area along the circumferential direction.

To keep the sensor device compact, the sender member and/or at least one receiving member can lie substantially in a plane. Preferably, the members lie in the same plane. The plane can be perpendicular to the axis of rotation. Such a plane has to be understood as a substantially flat object where one dimension is much smaller than the other two dimensions. Parts of the sensor device can for example be located on a front side of a PCB and other parts can be located on a back side of the PCB. In such an embodiment the sensor device would still lie substantially in a plane.

In an easy-to-manufacture embodiment, the sender member and/or at least one receiving member can comprise a conductive path on a PCB. The conductive paths can comprise or be the conductors.

The magnetic field can be an alternating magnetic field. This can for example be achieved by applying an alternating current at the sender member.

The invention will now be described in greater detail and in an exemplary manner using advantageous embodiments and with reference to the drawings. The described embodiments are only possible configurations in which, however, the individual features as described above can be provided independently of one another or can be omitted.

The scope of the present invention is defined by claim <NUM>.

Sensor devices <NUM> for measuring the rotational position of an element <NUM> that is rotatable about an axis of rotation <NUM> are shown. The rotatable element <NUM> can be a shaft <NUM>, for example a shaft of a car engine.

Each sensor device <NUM> comprises an electromagnetic transducer <NUM>, wherein each transducer <NUM> has at least one sender member <NUM> for emitting a magnetic field and at least two receiving members <NUM> for receiving the magnetic field. A metallic element is attached to the rotatable element <NUM> such that it rotates with the element <NUM>. In this example, four flaps <NUM> are connected to the shaft <NUM> and protrude sideways away from the shaft <NUM> perpendicular to the axis <NUM>.

The flaps <NUM> disturb the magnetic field generated by the sender member <NUM> so that the receiving members <NUM> receive different magnetic strengths of the magnetic field depending on the position of the flaps <NUM> and thus on the rotational position of the element <NUM>. From the signals received by the receiving members <NUM>, the rotational position of the element <NUM> can hence be deduced.

The sensor device <NUM> can comprise an arcuate carrier <NUM>, see for example <FIG>. The sensor device <NUM> and in particular the arcuate carrier <NUM> has a substantially partially annular shape or C-shape. An inner edge <NUM> and an outer edge <NUM> of the arcuate carrier are arc-shaped.

In the depicted example, the sensor device <NUM> comprises one controller <NUM> which is embodied as an integrated circuit <NUM>. The controller <NUM> is used for controlling the transducer <NUM>. The data of the controller <NUM> can then be processed in a further, non-depicted module. The controller <NUM> is arranged on the arcuate carrier <NUM>.

The sender member <NUM> comprises conductive paths <NUM> that form a coil <NUM>, in particular a spiral coil <NUM> on the arcuate carrier <NUM>, which is embodied as a PCB <NUM>. When running a current through the sender member <NUM>, a magnetic field results which is then disturbed by the flaps <NUM> and received by the receiving members <NUM>. Depending on whether the current runs in one direction or the other, for example clockwise or counterclockwise in the sender member <NUM>, the magnetic field is directed in one direction or the other.

Advantageously, the magnetic field that is generated is an alternating magnetic field. This magnetic field can be generated by applying an alternating current at the sender member <NUM>.

Each of the receiving members <NUM> comprises two conductors <NUM> embodied as conductive paths <NUM> on the PCB <NUM>. The conductive paths <NUM> resemble graphs of a periodic function, in particular a sine function. The conductors <NUM> thus have an elongated shape that is sinusoidal. The first conductor <NUM>, <NUM> starts at a contact section <NUM> and runs over one period of the periodic function along a circumferential direction C. At a junction <NUM>, it is connected to the second connector <NUM>, <NUM> which runs against the circumferential direction over one period back to the contact section <NUM>.

Each of the receiving members <NUM> and in particular the conductors <NUM>, <NUM>, <NUM> enclose or surround two surrounded areas <NUM> and resemble two eyes.

In the transducer <NUM>, the two receiving members <NUM> are shifted by a quarter of a period <NUM> of the periodic function.

In order to avoid a crossing of the conductive paths <NUM>, parts of the conductive paths <NUM> can be arranged on different levels which are for example separated by insulating layers or which can be arranged on a front side and a back side of the PCB <NUM>.

In the transducer <NUM>, the sender member <NUM> surrounds the receiving members <NUM> to save space.

The sender member <NUM> and the receiving members <NUM> are basically flat or planar and lie in the plane <NUM> that is perpendicular to the axis <NUM>. The entire sensor device <NUM> is basically a flat element arranged in this plane <NUM>.

In <FIG>, the details of a transducer <NUM> are shown. In <FIG>, a receiving member <NUM> is depicted in detail.

Each of the two receiving members <NUM>, 14A, 14B comprises two conductors <NUM>, <NUM>, <NUM> that together delimit two surrounded areas <NUM>, the surrounded areas <NUM> each expanding and contracting in a circumferential direction C about the axis of rotation <NUM>. The combination of the two conductors <NUM>, <NUM>, <NUM> is not entirely closed. In particular around the first surrounded areas <NUM>, 51A, 52A the conductors are slightly spaced apart at the contact section <NUM> at which contact to the conductors <NUM> is made. The conductors <NUM> circumscribe or surround or substantially enclose the surrounded areas <NUM>.

The surrounded areas <NUM> are basically planar. They lie one behind the other in the circumferential direction C. The two neighbouring surrounded areas <NUM> are separated from each other by a crossing <NUM> of the conductors <NUM>. In this area of crossing, the two conductors <NUM> can be located at different levels to avoid a current flow. For example, they can be located on a front side and a back side of the PCB <NUM>.

Each of the surrounded areas <NUM> tapers in and against the circumferential direction C at their ends. The surrounded area <NUM> is widest at a middle section <NUM>, the width being measured in a radial direction R that points away from the axis <NUM> and is perpendicular to the axis <NUM>. The radial direction R is further perpendicular to the circumferential direction C. At end sections <NUM> and <NUM>, the surrounded areas <NUM> are wedge-like with sharp tips. Each of the surrounded areas <NUM> is thus eye-shaped or lentil-shaped.

Each of the two conductors <NUM>, <NUM>, <NUM> has an elongated shape that resembles a graph of a spatially periodic function, in particular a sine function.

The two receiving members <NUM> have an identical shape and are shifted by a quarter of a period <NUM> to each other along the circumferential direction C. Such a mechanical shifting relates to an electrical shifting of Pi/<NUM> and is approximately half a length <NUM> of a surrounded area <NUM>.

The two conductors <NUM> are substantially symmetrical to each other with respect to a reflection at a cylindrical circumferential surface.

The sections of the two conductors <NUM> that enclose the surrounded areas <NUM> comprise mainly or only curved sections in order to improve the signal quality. No straight sections are present in these sections. Moreover, the two conductors <NUM> comprise no straight sections that run in the radial direction R. Although in the area of the contact sections <NUM>, straight sections are present, these sections do not run in the radial direction R.

The sender member <NUM> surrounds the receiving members <NUM>.

Each distance <NUM>, <NUM> between the sender member <NUM> and the receiving members <NUM> along the circumferential direction C is less than a quarter of the period <NUM> and less than one quarter of the length <NUM> of the sender member <NUM> along the circumferential direction C and further less than one quarter of the length <NUM> of the receiving member <NUM> along the circumferential direction <NUM>.

In <FIG>, a further embodiment of a sensor device <NUM> is shown. The transducer <NUM> again comprises a sender member <NUM> and two receiving members <NUM>. In each of the two receiving members <NUM>, the conductors <NUM> surround two convex surrounded areas <NUM>. At each of their ends in and against the circumferential direction C the surrounded areas <NUM> taper. The surrounding areas <NUM> thus have an eye-shape.

In <FIG>, the rotatable element <NUM> is shown. Four flaps <NUM> are arranged behind each other in the circumferential direction C and each protrudes along the radial direction R. The number of flaps can be different in different embodiments. For example, three flaps <NUM> or five flaps <NUM> could be present.

In <FIG>, a further embodiment of a sensor device <NUM> is shown. Similar to the one shown in <FIG>, a transducer <NUM> is present. Further, this embodiment comprises a controller <NUM> in the form of an integrated circuit <NUM> that is located on a PCB <NUM>.

Claim 1:
Sensor device (<NUM>) for measuring the rotational position of an element (<NUM>) that is rotatable about an axis of rotation (<NUM>), the sensor device (<NUM>) comprising at least one sender member (<NUM>) for emitting a magnetic field and at least two receiving members (<NUM>) for receiving the magnetic field, wherein each of the at least two receiving members (<NUM>) comprises two conductors (<NUM>) that together delimit at least two surrounded areas (<NUM>), wherein each of the surrounded areas (<NUM>) tapers in and against a circumferential direction (C) at their ends, characterized in that at least one of the surrounded areas (<NUM>) is a non-convex surrounded area.