Inductive position sensor device and drive device

Abstract

The present invention relates to an inductive position sensor device for detecting the position of a coupling member that can be arranged on a movable actuator member of an electric machine (2). The device comprises at least one transmitter coil (8, 8') for generating electromagnetic waves, at least one receiver coil (9, 9') for detecting the electromagnetic waves generated by the transmitter coil (8) and acted on by the actuator member, and a computing unit (11), the computing unit (11) being configured to operate the transmitter coil (8) and evaluate the electromagnetic waves detected by the receiver coil (9, 9') in order to determine the position, the coils (8, 9) being arranged on the front side of a common printed circuit board (6), and the computing unit (11) being arranged on the back side of the printed circuit board (6), the coils (8, 8', 9, 9') being electrically connected to the computing unit (11) via connecting lines (12, 13) extending along and through the printed circuit board (6). It is proposed that the connecting lines (12, 13) extend substantially parallel to each other.

Description

Technical Field

[0001] The present invention relates to an inductive position sensor device for detecting the position of a coupling member that can be arranged on a movable actuator member of an electromechanical device. The inductive position sensor device includes a transmission coil that generates electromagnetic waves, at least one reception coil that detects the electromagnetic waves generated from the transmission coil and affected by the action of the coupling member, and a calculation unit. The calculation unit is configured to operate the transmission coil and evaluate the electromagnetic waves detected by the reception coil in order to specify the position of the actuator member. The coil and the calculation unit are arranged on a common printed circuit board. The coil is arranged on the front surface of the printed circuit board, and the calculation unit is arranged on the back surface of the printed circuit board on the side opposite to the front surface. The coil is electrically connected to the calculation unit via connection lines that extend along and through the printed circuit board.

[0002] Furthermore, the present invention relates to a drive device, particularly to a drive device for a braking device of a motor vehicle. The drive device includes an electromechanical device and an inductive position sensor device associated therewith. The inductive position sensor device detects the position of a movable actuator member of the electromechanical device, particularly a rotor actuator or a linear actuator.

Background Art

[0003] Background Art Inductive position sensor devices are already known from the prior art and are known in particular in the form of rotor position sensor devices for detecting the rotor position or angular position of an electromechanical rotor. These devices utilize the effect that, in particular on the end face side, they are exposed to the electromagnetic field of the electromagnetic waves of a transmitting coil depending on the angular position of a coupling member attached to the rotor, and these electromagnetic waves are subject to a traceable effect. For the purpose of operating the transmitting coil and evaluating the results detected by the receiving coil, this type of sensor device usually also has a control unit or a computing unit, for example in the form of a microprocessor or an application-specific integrated circuit (ASIC). In that case, the computing unit is configured in particular to operate the transmitting coil in order to generate a modulated signal. For the purpose of enabling the evaluation of the signal and thus the evaluation of the effect exerted on the signal by the electromechanical rotor, the signal received by the receiving coil is then demodulated by this computing unit or, optionally, by a further computing unit. Thus, the electromagnetic waves are incident from the transmitting coil to the coupling member and further from the coupling member to the receiving coil, and thus information regarding the rotor angular position can be obtained from the electromagnetic signal detected by the receiving coil.

[0004] Generally, the computing unit, as well as at least two coils, namely the transmitting coil and the receiving coil, are arranged on the same printed circuit board for the purpose of realizing a simple electrical and / or signal-technical connection between the computing unit and the coils and further for the purpose of realizing a compact structural form. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0005] DISCLOSURE OF THE INVENTION The position sensor device according to the present invention having the features described in claim 1 has the advantage that, in particular, a so-called shielding layer or shield layer can be omitted, so that the printed wiring board can be manufactured at a lower cost with less labor than before. Conventionally, the shielding layer or shield layer is incorporated to block or limit the interfering electromagnetic field between the individual planes of the printed wiring board. However, by configuring the position sensor device according to the present invention, this type of electromagnetic interference signal or interfering electromagnetic field is blocked from the beginning or is significantly reduced to the extent that at least an additional shielding layer can be omitted. As a result, in particular, it becomes possible to reduce the number of layers or planes of the printed wiring board. According to the present invention, this is achieved by the connection lines connecting the computing unit to the coil extending at least substantially parallel to each other. By this parallel extension, the induction in the region of the connection lines is minimized, thereby preventing an offset in the output signal and thus optimizing the measurement result. Moreover, preferably, the connection lines are designed to be as short as possible.

Means for Solving the Problems

[0006] According to one preferred embodiment of the present invention, the connection lines extend parallel to each other at least in some sections on different planes of the printed wiring board. Thus, in this case, the connection lines are not located on the same plane of the printed wiring board, but are separated from each other through the planes of the printed wiring board. By extending on different planes, a particularly compact structural form of the printed wiring board is ensured, and it is also possible to form the connection lines so that they are directly above and below each other on the printed wiring board, thereby making it possible to position them particularly close to each other.

[0007] More preferably, it is proposed that the connecting lines extend parallel to each other such that at least a part of each of them is vertically positioned in different planes. When the printed circuit board is formed in an annular or annular ring shape as in the case of being configured as a rotor position sensor, these planes are vertically positioned in the axial direction, and the connecting lines extending parallel to each other are directly vertically positioned in the axial direction. Thereby, a particularly compact structural form and an advantageous reduction of the electromagnetic control effect are achieved.

[0008] According to an alternative embodiment of the present invention, a plurality of connecting lines or at least two of these connecting lines extend substantially parallel to each other on one plane of the printed circuit board. Thereby, the connecting lines are positioned side by side on or on one plane of the printed circuit board, rather than vertically. Also in this case, the electromagnetic control effect is advantageously reduced, and the arrangement on one plane can be realized at low cost in some cases.

[0009] More preferably, it is proposed that the printed circuit board has first, second, third, and fourth planes or layers positioned vertically, and at least one of the coils is at least partially arranged on the first plane and on the second plane, a computing unit is arranged on the fourth plane, and a section of connecting lines extending parallel to each other is arranged on at least the third and / or fourth planes. Thus, the printed circuit board is composed of four layers or four planes. In this case, preferably, coils are arranged on two planes, and a computing unit and a connecting line or at least a section of connecting lines extending parallel to each other are located on the remaining two planes. Thereby, a preferable separation of functions in the sensor device is ensured, and due to this separation, the printed circuit board can be manufactured at low cost together with the members arranged thereon. In the third and / or fourth planes, by routing or laying a section of the connecting lines extending parallel to each other, there is an advantage that the connecting lines can be positioned independently of the spread of the coils, whereby the extension of the connecting lines can be optimally designed.

[0010] More preferably, it is proposed that the position sensor device has at least one transmitting coil and at least two receiving coils, and these receiving coils are particularly arranged on the actuator member with a shift from each other. Thereby, a high and unambiguous resolution of the received signal, or an unambiguous and particularly absolute position determination of the actuator member is brought about.

[0011] More preferably, it is proposed that each individual receiving coil extends over at least a first plane and a second plane. Thus, the receiving coils respectively extend over the top two planes of the printed circuit board, thereby ensuring an advantageous coil extension form, according to which, in particular, a plurality of sections of the same coil can be crossed by laying them on different planes respectively.

[0012] More preferably, it is proposed that at least one transmitting coil extends only over the first plane or over at least the first plane and the second plane.

[0013] Particularly preferably, the printed circuit board is formed without a shielding layer provided, and thus the printed circuit board is not made of copper in particular and does not have an intermediate layer that prevents interference electromagnetic fields or electromagnetic signals from migrating to the next plane. Since the position sensor device is configured according to the present invention, there is no need to provide this kind of shielding layer, and thus here, providing it is preferably avoided. Thereby, in particular, the manufacturing cost for the printed circuit board is significantly reduced.

[0014] Particularly preferably, the printed circuit board is formed in an annular disk shape, particularly in an annular ring disk shape, or in a strip shape according to whether the position sensor device is configured as a rotor position sensor device or as a linear actuator position sensor device.

[0015] More preferably, for the purpose of improving the EMC compatibility of the position sensor device, it is proposed that at least one more EMC interference suppression capacitor, preferably a plurality of EMC interference suppression capacitors, be arranged on the back surface of the printed circuit board.

[0016] The drive device according to the present invention having the features of claim 12 is excellent in that the position sensor device is configured according to the present invention. Thereby, the advantages already mentioned are brought about.

[0017] Further advantages and preferred features and combinations of features will become apparent in particular from the above description and the claims. Hereinafter, the present invention will be described in detail with reference to the drawings.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0019] Figure 1 schematically shows an advantageous drive device 1 for a load, not shown in detail here, for example for an automotive braking system, in particular for a parking brake. The drive device 1 has an electromechanical machine 2, which has a drive shaft 3 that is rotatably supported within a housing (not shown here), supports a rotor 4, and a stator 4' fixed to the housing is associated with the rotor 4. For the purpose of driving the load, the drive shaft 3 is mechanically coupled to or can be coupled to the load.

[0020] A position sensor device 5 is associated with the rotor 4 of the electromechanical machine 2 here in the form of a rotor position sensor device, which detects the rotor angular position of the rotor 4 by induction. For this purpose, the position sensor device 5 has a printed circuit board 6, which is formed in an annular ring disk shape according to this embodiment and is arranged coaxially with the drive shaft 3 and associated with the end face of the rotor 4. The printed circuit board 6 supports at least one transmission coil 8 and at least two reception coils 9, 9' on its front face 7 facing the rotor 4. A calculation unit 11 is arranged on the back face 10 of the printed circuit board 6 opposite the rotor 4, which is configured as an application-specific integrated circuit (ASIC) according to this embodiment and is electrically connected to both coils 8, 9, 9'. In particular, the coils 8, 9, 9' are printed on the printed circuit board 6, in particular on different planes of the printed circuit board 6, as will be explained in detail later. In Figure 1, for the sake of clarity, the coils 8, 9, 9' are depicted as rather simplified blocks. Preferably, at least one EMC interference suppression capacitor 14 is further arranged on the back face 10, which is electrically connected in particular to the calculation unit 11 and / or the coils 8, 9, 9'.

[0021] The calculation unit 11 is configured to operate the transmission coil 8 to transmit a signal by electromagnetic waves, and these electromagnetic waves penetrate the coupling member 15 of the position sensor device 5, which is disposed opposite the printed wiring board 6 on the end face side of the rotor 4. The electromagnetic waves are affected by the action of the coupling member 15 and are reflected or guided to the reception coil 9. At this time, the electromagnetic waves are affected depending on the rotational angular position of the coupling member 15 or the rotor 4. The calculation unit 11 is configured to demodulate the signal detected by the reception coil 9 and affected by the rotor 4, and to specify the rotor angular position of the rotor 4 depending on the detected signal. Since the method of specifying the rotor angular position using an inductive rotor position sensor device, which is generally also referred to as an inductive rotor position sensor, is basically known, the specific functions and implementation of this method will not be described in detail here.

[0022] FIG. 2 shows a simplified plan view of the position sensor device 5. The printed wiring board 6 is formed in an annular ring shape as described above. The coils 8 and 9 are vertically positioned in different planes of the printed wiring board 6. Therefore, as seen in the plan view shown in FIG. 2, the coils 8 and 9 intersect at a plurality of locations. Since the calculation unit 11 is located behind the coils 8 and 9, as seen in the plan view, the coils 8 and 9 are located above the calculation unit 11. Therefore, the calculation unit 11 and the coils 8 and 9 are not only arranged on different sides of the printed wiring board 6, but are also arranged so as to be directly vertically positioned, thereby ensuring a particularly compact structural form with a short connection section to the calculation unit 11.

[0023] According to this embodiment, the printed wiring board is formed of four layers and thus has four planes. This is shown as a simplified side view in FIG. 3. On the first plane L1, a part of the transmission coil 8 and the reception coils 9 and 9' are located, and these intersect even, for example, in their extended forms.

[0024] On a second plane L2 located below this, other portions of the transmission coil 8 and the reception coils 9, 9' are respectively formed. In particular, a single transmission coil 8 and two reception coils 9, 9' are provided, and these extend across the planes L1 and L2 respectively.

[0025] As described above, on the back surface 10 of the printed wiring board 6 in the lowermost plane L4, the calculation unit 11 is arranged. In the third plane L3 located between the plane L4 and the plane L2 and in the plane L4, connection lines 12 of the transmission coil 8 and connection lines 13 of the reception coils 9, 9' are formed, and by these connection lines 12, 13, the transmission coils 8, 8' and the reception coils 9, 9' are electrically connected to the calculation unit 11. The connection lines 12, 13 of course extend through all the planes necessary to reach the individual coils 8, 8', 9, 9'. However, as shown simplified in FIG. 3, in the planes L3 and L4, the connection lines 12, 13 extend at least substantially parallel to each other.

[0026] FIG. 4 shows a simplified detailed plan view of the printed wiring board 6. In this case, the connection lines 12, 13 in the planes L3, L4 that extend radially or do not extend in the axial direction extend parallel to each other so that they are directly located above and below each other. In this case, the connection lines 12, 13 extend as long as possible between the calculation unit 11 and the coils 8, 9 and extend parallel to each other on the third and fourth layers L3, L4, or extend parallel to each other on the same layers L3, L4. As a result, since the inductive action in the connection region is minimized, the offset in the signal is also minimized. At least, it can be ignored to the extent that no mismeasurement is caused or the output signal is as linear as possible. Moreover, preferably, the connection lines 12, 13 between the calculation unit 11 and the coils 8, 9 are formed as short as possible for the purpose of minimizing the interfering electromagnetic field or signal generated by induction.

[0027] In the case of today's sensor devices, due to the induction in the coil connection area, a large offset and thus a large linear deviation are caused. Therefore, the calculation unit is usually not attached to the back of a 4-layer printed circuit board. In contrast, the advantageous embodiment of the sensor device 5 according to this embodiment is suitable for enabling this to be done even in a 4-layer printed circuit board without the need to incorporate additional shielding layers between individual planes. From the demodulated signals of the receiving coils 9, 9', sinusoidal and cosinusoidal output signals are obtained. For the purpose of obtaining a linear signal that depends on displacement or angle, ATAN is formed. The more the signal approximates a cosine wave and a sine wave, the smaller the resulting harmonic signal components and the more linear the output signal. This linearity can be quantified. If a complete ATAN (straight line) is derived from the sine wave and the cosine wave by ATAN (signal 1, signal 2), a linear deviation is obtained as the deviation from the ideal sine wave signal and cosine wave signal. Generally, since only a finite number of interpolation fulcrums of the displacement-signal curve can be stored, a large non-linearity means low accuracy or an increase in the complexity of calibration. When the electromechanical adjustment is incomplete, vibrations and noise may occur at that time. For the purpose of reducing such drawbacks, conventionally, a shielding layer made of, for example, copper is installed between planes. Due to the advantageous configuration of the position sensor device 5 shown here, this type of layer can be omitted for the above reasons, thereby making the printed circuit board 6 low-cost as a whole and more space-saving.

[0028] According to this embodiment, the actuator member to be inspected is the rotor 4, whereas according to other embodiments, the actuator member is the linear actuator member 15 as shown in FIG. 5. The difference between this embodiment and the above-described embodiments is that the printed wiring board 6 is formed not in an annular ring shape but in a strip shape, and there, the coils 8, 9, 8', 9' extend in the longitudinal extending direction of the strip-shaped printed wiring board 6. In other respects, also in this case, the calculation unit 11 is arranged in the plane L4, and the coils are arranged in the planes L1, L2. Also in this case, the connection lines from the coils to the calculation unit 11 are formed so as to be at least substantially parallel to each other in different planes, particularly directly above and below each other.

[0029] Instead of extending the connection lines 12, 13 vertically in different layers, it is also conceivable to extend the connection lines 12, 13 or at least one of the connection lines 12, 13 parallel to each other in one of the planes L1 to L4 or within a layer. Also by this, the interference signal can be reduced by parallel extension.

Claims

1. An inductive position sensor device (5) for detecting the position of a coupling member that can be arranged on a movable actuator member of an electromechanical device (2), wherein the inductive position sensor device (5) includes at least one transmitting coil (8, 8') that generates an electromagnetic wave, at least one receiving coil (9, 9') that detects the electromagnetic wave generated from the transmitting coil (8) and affected by the action of the actuator member, and a calculation unit (11). The calculation unit (11) is configured to operate the transmitting coil (8) and evaluate the electromagnetic wave detected by the receiving coil (9, 9') in order to identify the position. The coils (8, 9) are arranged on the front surface (7) of a common printed circuit board (6), the calculation unit (11) is arranged on the back surface (10) of the printed circuit board (6), and the coils (8, 8', 9, 9') are electrically connected to the calculation unit (11) via a pair of connection lines (12, 13) that extend along and through the printed circuit board (6). In the inductive position sensor device (5), the connection lines (12, 13) extend substantially parallel to each other for each pair, the printed circuit board (6) has first, second, third, and fourth planes (L1 to L4) positioned one above the other. At least one of the coils (8, 9, 8', 9') is at least partially arranged on the first plane (L1) and the second plane (L2), the calculation unit (11) is arranged on the fourth plane (L4), and sections of the connection lines (12, 13) that extend parallel to each other are located on at least the third plane (L3) and / or the fourth plane (L4), the connection lines (12, 13) extend at least substantially parallel to each other on different planes (L3, L4) of the printed circuit board (6), characterized by an inductive position sensor device (5).

2. The inductive position sensor device (5) according to claim 1, wherein the connection lines (12, 13) extend parallel to each other so as to be positioned one above the other in at least some sections on different planes (L3, L4).

3. The connecting wires (12, 13) extend at least substantially parallel to each other on one plane (L3, L4) of the printed circuit board, for the inductive position sensor device (5) according to claim 1 or 2.

4. One transmitting coil (8) and at least two receiving coils (9, 9') are provided, and the receiving coils (9, 9') are displaced from each other and arranged on the actuator member, for the inductive position sensor device (5) according to any one of claims 1 to 3.

5. Each of the receiving coils (9, 9') extends at least over the first plane and the second plane, for the inductive position sensor device (5) according to any one of claims 1 to 4.

6. At least one of the transmitting coils (8) extends only over the first plane (L1) or at least over the first plane and the second plane, for the inductive position sensor device (5) according to any one of claims 1 to 5.

7. The printed circuit board (6) is formed without a shielding layer, for the inductive position sensor device (5) according to any one of claims 1 to 6.

8. The printed circuit board (6) is formed in an annular disk shape, particularly in an annular ring disk shape, or in a strip shape, for the inductive position sensor device (5) according to any one of claims 1 to 7.

9. At least one EMC interference suppression capacitor (14) is arranged on the back surface (10), for the inductive position sensor device (5) according to any one of claims 1 to 8.

10. A drive device (1), particularly a drive device (1) for an automotive parking brake, wherein the drive device (1) comprises an electromechanic and an inductive position sensor device (5) associated with the electromechanic, and the inductive position sensor device (5) detects the position of a movable actuator member of the electromechanic, particularly a rotor (4) or a linear actuator (15), in the drive device (1). A drive device (1), characterized by having the configuration of the inductive position sensor device (5) according to any one of claims 1 to 9.

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