Inductive position sensor device and braking system having the inductive position sensor device

Abstract

The present invention relates to an inductive position sensor device (1) for detecting the position of a position transducer element (3) having a position receiving device (2), the position receiving device (2) comprising a multilayer printed circuit board (9) having a coil assembly (4), the coil assembly (4) comprising at least one excitation coil (5) and at least a first receiving coil (6) and a second receiving coil (7), the first receiving coil (6) and the second receiving coil (7) each comprising a number of windings (8, 10, 11, 12, 13, 14) at least partially surrounded by the excitation coil (5), the first receiving coil (6) comprising a compensation winding (8) arranged at least in an upper and / or lower portion of a portion (24) of the excitation coil (5).

Description

Technical Field

[0001] The present invention relates to an inductive position sensor device according to the preamble of claim 1 and a braking system comprising such an inductive position sensor device according to the preamble of claim 9.

Background Art

[0002] Inductive position sensors are widely used in the automotive field. Such position sensors are used, for example, to detect the linear or rotational angular position of a moving element. For example, a coil system that indicates the position of a moving position encoder element via mutual coupling (electric field and voltage) is used as a position receiving device. At least one excitation coil and at least two receiving coils are used. Such coils are known to be printed / applied to a printed circuit board, as is known, for example, from the document, US Patent Application Publication No. 2020400465A1.

[0003] The position encoder element is typically a moving component made of a conductive, usually non-ferromagnetic material. This may be, for example, the cylinder piston of a master brake cylinder of a brake actuator or the impeller of a drive shaft of an electric motor.

[0004] Such sensors operate according to the inductive principle. In this case, the fact that both conductive and ferromagnetic materials affect the characteristics of the electromagnetic coil is utilized. The change in the coupling between the excitation coil and the at least two receiving coils caused by the metal element results in a change in voltage, which is registered and evaluated by an evaluation unit.

[0005] In the case of an angular sensor, currently, a 360° wraparound coil assembly is commonly used. In the case of a C-shaped coil structure, the surface area can be significantly reduced by the "Pos1 / 2<>Neg1 / 2 and Pos1 / 4<>Neg1 / 2<>Pos1 / 4" receiving coil structure. The C-shaped coil structure (or C-shaped printed circuit board) provides a much more cost-effective alternative to the 360° variant. However, when compressing the available surface area required by the "Pos1 / 2<>Neg1 / 2 and Pos1 / 4<>Neg1 / 2<>Pos1 / 4" receiving coil structure to the maximum, an imbalance occurs in the generated signal. One of the two signals from the two receiving coils is asymmetrically loaded to such an extent that a large offset occurs. Therefore, the signal average value of the asymmetrically loaded receiving coil is no longer optimally adapted to a signal evaluation electronic device system, such as an analog-to-digital converter. Consequently, due to the different offset voltages of the first output signal and the second output signal, it is not possible to amplify both signals optimally to make the best use of the available voltage range. As a result, the robustness of the signal is impaired.

[0006] Therefore, an object of the present invention is to reduce the offset voltage of the cosine signal of a motor position sensor in order to enable the maximum amplitude gain of both received signals (sine and cosine). Consequently, the robustness against mechanical tolerances in the installed sensor's printed circuit board and the sensor object (e.g., impeller) is increased. As a result, waste in production is reduced, and it is robust with respect to safety-critical conditions during position drift.

[0007] An object of the present invention is to provide an inductive position sensor device in which the generation of offsets of the signals of at least two output receiving coils is small.

Summary of the Invention

Means for Solving the Problems

[0008] The present invention provides an inductive position sensor device for detecting the positional location of a position encoder element having a position receiving device, the position receiving device comprising a printed circuit board of multilayer design and having a coil assembly, the coil assembly comprising at least one excitation coil and at least a first receiving coil and a second receiving coil, the first receiving coil and the second receiving coil each comprising a plurality of windings at least partially surrounded by the excitation coil, the first receiving coil comprising compensation windings arranged in a specific region above and / or below at least a sub-section of the excitation coil.

[0009] By inserting compensation windings into the receiving coil affected by the offset, an additional magnetic field (or voltage) from the excitation coil is induced in the receiving coil. Thus, the voltage offset is shifted in the desired direction of the signal of the second receiving coil.

[0010] Depending on the position of the compensation windings relative to the excitation coil on the printed circuit board, the coupling of the excitation magnetic field is affected by the position of the position encoder element in the compensation windings. This results in a perturbation to the compensation magnetic field depending on the position of the position encoder element. The proposed compensation windings also address these adversities by virtue of the fact that they are explicitly arranged in the region of the sensor object on which they are located.

[0011] Nevertheless, in order to achieve offset compensation independent of the position encoder element, the length of the compensation windings (or the angular aperture in the case of an angular sensor) is selected such that the total surface area of the position encoder element and the clearance of the position encoder element (e.g., the non-blade of the angular sensor) always exceed the compensation windings. Thus, the influence of the position of the position encoder is offset.

[0012] This has the advantage of providing a high degree of robustness against mechanical position changes. In addition, since there are no constraints, the circuit design of the printed circuit board is made independent. As a result, the space requirements on the printed circuit board are significantly reduced, leading to cost savings.

[0013] In addition, the compensation winding assembly according to the present invention has the advantage that the position sensor device outputs good measurement results without regular calibration.

[0014] The multilayer printed circuit board preferably comprises a first layer, a second layer, and at least one intermediate layer arranged between the first layer and the second layer. The excitation coil comprises a plurality of windings applied to the first layer and the second layer. The compensation winding of the first receiving coil is applied to the first intermediate layer, and the compensation winding is arranged in a specific region in the vertical region between the windings of the excitation coil of the first layer and the windings of the excitation coil of the second layer.

[0015] In addition, the compensation winding is integrated with the excitation coil in the printed circuit board layer such that only a part of the excitation magnetic field required for compensation is coupled to the compensation winding. Therefore, there is also virtually no additional surface area required for the compensation winding for the entire printed circuit board.

[0016] According to a preferred embodiment, the first receiving coil is applied to the first intermediate layer and the second intermediate layer by its windings. According to another preferred embodiment, the second receiving coil is applied to the first intermediate layer and the second intermediate layer by its windings, and the second intermediate layer is arranged between the first layer and the second layer.

[0017] The windings of the first receiving coil and the second receiving coil preferably each comprise a plurality of positive and negative windings, and these positive and negative windings are surrounded diametrically by the windings of the excitation coil.

[0018] The first receiving coil is preferably a cosine receiving coil. The second receiving coil is preferably a sine receiving coil.

[0019] Furthermore, the excitation coil, the first receiving coil, and the second receiving coil each comprise a connection to an evaluation unit.

[0020] The inductive position sensor device according to the present invention is used in the braking system of a motor vehicle. There, the position sensor device is used to determine the movement of a brake cylinder piston or to determine the rotor position of a drive shaft having an impeller of an electric motor. In this case, the brake cylinder piston or the impeller represents the position encoder element of the position sensor device.

[0021] A further preferred embodiment of the present invention will become apparent from the following description of exemplary embodiments based on the following drawings.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0023] Figure 1 shows a first exemplary inductive position sensor device 1 comprising a position receiving device 2 and a position encoder element 3. The position receiving device 2 comprises a printed circuit board (not shown) having a coil assembly 4 including at least three coils. In the example shown, the position encoder element 3 is in the form of an impeller 26. The impeller 26 is designed to be fixed on a drive shaft (not shown) of an electric motor via its fastening ring 27. The position receiving device 2 and the position encoder element 3 are arranged spatially with a slight interval from each other, on top of each other or adjacent to each other. The impeller 26 is made of a metallic material. The impeller 26 is made of a non-ferromagnetic material. The impeller 26 is conductive.

[0024] Figure 2 shows this position sensor device 1 in more detail. The impeller 26 is shown in a slightly transparent state to illustrate the underlying coil assembly 4 below. The exact design of the coil assembly 4 will be described in more detail in FIGS. 4-6. The coil assembly 4 comprises at least one excitation coil 5 and at least one first receiving coil 6. The first receiving coil 6 comprises a plurality of windings including compensation windings 8. The impeller 26 comprises at least one blade 22 and at least one blade recess 23. The impeller 26 may be provided with a plurality of blades and blade recesses alternating in the rotational direction. The impeller 26 is made of, for example, an aluminum material and rotates by its blade 22 when driven by its coil assembly 4 via a printed circuit board (not shown) by a drive shaft of an electric motor. The blade 22 repeatedly slips over the coil assembly 4 and, in the process, affects the induced voltages of the first receiving coil 6 and the second receiving coil. The rotational position of the drive shaft of the electric motor is determined by changing the coupling of the excitation magnetic field from the excitation coil 5 to the first receiving coil and the second receiving coil, which results from the blade 22 and the subsequent blade recess 23 slipping.

[0025] The compensation winding 8 of the first receiving coil 6 is arranged in a specific region above or below at least a sub-section of the excitation coil 5. In this case, the compensation winding 8 follows the curved shape of the sub-section of the excitation coil 5.

[0026] Furthermore, the compensation winding 8 is arranged such that the fastening ring 28 of the impeller 26 is not located above it. The compensation winding 8 is arranged such that the blades 22 and the blade recesses 23 move over it.

[0027] In the embodiment, the position receiving device 2 is C-shaped according to FIGS. 1 and 2. This means that the printed circuit board (not shown) and the coil assembly 4 are also C-shaped. Such a C-shape requires less installation space, but higher requirements are imposed on the signal quality.

[0028] FIG. 3 shows a second exemplary inductive position sensor device 1 comprising a position receiving device 2 and a position encoder element 3. The position receiving device 2 similarly comprises a printed circuit board (not shown) having a coil assembly 4 including at least three coils. In the example shown, the position encoder element 3 is a cylinder piston 27. The cylinder piston 27 belongs to, for example, the master brake cylinder of a brake actuator. When the brake actuator is actuated, the cylinder piston 27 moves parallel to the position receiving device 2. As a result, the position or the movement distance of the cylinder piston 27 can be detected by the position receiving device 2. This movement distance represents, for example, the driver's brake request. The position receiving device 2 is mounted, for example, inside or on the cylinder housing of the brake actuator, in which the cylinder piston 27 moves linearly.

[0029] The coil assembly 4 also comprises an excitation coil 5 and a first receiving coil 6 having a compensation winding 8. The compensation winding 8 of the first receiving coil 6 is arranged in a specific region above or below at least a sub-section of the excitation coil 5. In this case, the compensation winding 8 follows the linear shape of the sub-section of the excitation coil 5. In the example shown, the position receiving device 2 is rectangular.

[0030] FIG. 4 shows in more detail the coil assembly 4 of the position receiving device 2 in the first exemplary inductive position sensor device 1 from FIG. 1.

[0031] The coil assembly 4 comprises an excitation coil 5 having a connection portion 15, a first receiving coil 6 having a connection portion 16, and a second receiving coil 7 having a connection portion 17. The first receiving coil 6 comprises a plurality of windings. A first positive winding 10 is provided at the connection portion 16, the first positive winding 10 transitions to a negative winding 11, and further the negative winding 11 transitions to a second positive winding 12. A compensation winding 8 branches off from the second positive winding 12. The compensation winding 8 extends over a sub-section 24 of the excitation coil 5. In this case, the compensation winding 8 is located above or below the sub-section 24 of the excitation coil 5. The receiving coil 6 is a so-called cosine receiving coil.

[0032] The second receiving coil 7 comprises a positive winding 13 that transitions to a negative winding 14 at the connection portion 17.

[0033] The windings 10, 11, and 12 of the first receiving coil 6, and the windings 13 and 14 of the second receiving coil 6 are surrounded diametrically by the excitation coil 5. Thus, a voltage is induced in the windings 10 - 14 of the first receiving coil 6 and the second receiving coil 7 by the excitation magnetic field of the excitation coil 5.

[0034] In this case, the compensation winding 8 of the first receiving coil 6 is exposed to the excitation magnetic field of the excitation coil 5 such that the portion of the excitation magnetic field passing up to the compensation winding 8 induces an additional voltage defined in the compensation winding 8. This voltage corresponds to the portion necessary to compensate for the shifted offset.

[0035] FIG. 5 shows a similar structure of the coil assembly 4 of the second exemplary inductive position sensor device 1 from FIG. 3. In this case, the coil assembly 4 is rectangular. The first receiving coil 6 and the second receiving coil 7 have the same number and type of windings 8, 10 - 14 as described in the above embodiment.

[0036] Also in this case, the compensation winding 8 extends from the first receiving coil 6 over a sub - section of the excitation coil 5.

[0037] FIG. 6 shows in cross - section a position receiving device 2 having a multilayer printed circuit board 9. The printed circuit board 9 comprises a first (upper) layer 18 and a second (lower) layer 19. Therein, a first intermediate layer 20 and a second intermediate layer 25 are provided. The first intermediate layer 20 faces the second layer 19. The second intermediate layer 25 faces the first layer 18.

[0038] As an example, the excitation coil 5 comprises a plurality of windings 29. These windings 29 are applied to the first layer 18 and the second layer 19 simultaneously. At a plurality of connection points, the excitation coil passes from the first layer 18 to the second layer 19 and back again. By energizing the excitation coil 5 with an alternating current, an excitation magnetic field 21 is generated. The excitation magnetic field 21 acts on the windings of the first receiving coil 6 and the second receiving coil 7. In particular, the excitation magnetic field 21 acts on the compensation winding 8 from the first receiving coil 6.

[0039] The positive and negative windings of the first receiving coil 6 and the second receiving coil 7 are located on the sides of the winding 29 of the exciting coil 5. The positive and negative windings are surrounded by the exciting coil 5 and are arranged slightly away from their winding 29. As a result, a weak exciting magnetic field 21 is applied to the positive and negative windings. The positive and negative windings of the first receiving coil 6 and the second receiving coil 7 are located in the intermediate layers 20 and 25 of the printed circuit board 9. The positive and negative windings of the respective receiving coils 6 and 7 can pass from the first intermediate layer 20 to the second intermediate layer 25 and return again at the corresponding connection points. As a result, the positive and negative windings of the receiving coils 6 and 7 extend vertically through the printed circuit board 9. The positive and negative windings of the receiving coils 6 and 7 run in the horizontal direction as shown in FIGS. 3 to 5.

[0040] As an example, the compensating winding 8 of the first exciting coil 5 is applied to the first intermediate layer 20. As an example, the sub-region of the compensating winding 8 is located in the vertical region between the first layer 18 and the second layer 19 of the printed circuit board 9 and the exciting coil 5 to which it is applied. This means that the compensating winding 8 is within the strong effective range of the exciting magnetic field 21.

[0041] As a result, the exciting magnetic field 21 induces a voltage not only in the positive and negative windings of the first receiving coil 6 but also in the compensating winding 8. Therefore, the signal offset of the first receiving coil 6 changes so that the signal from the first receiving coil 6 approximates the signal from the second receiving coil 7. Note that the present invention may also include the following aspects: 1. An inductive position sensor device (1) for detecting the positional location of a position encoder element (3) having a position receiving device (2), wherein the position receiving device (2) comprises a printed circuit board (9) with a multilayer design and has a coil assembly (4), and the coil assembly (4) comprises at least one excitation coil (5), at least a first receiving coil (6) and a second receiving coil (7), and the first receiving coil (6) and the second receiving coil (7) each comprise a plurality of windings (8, 10, 11, 12, 13, 14) at least partially surrounded by the excitation coil (5). In the inductive position sensor device (1), the first receiving coil (6) comprises a compensation winding (8) arranged in a specific region above and / or below at least a sub-section (24) of the excitation coil (5), and the inductive position sensor device (1) is characterized by this. 2. The printed circuit board (9) with the multilayer design comprises a first layer (18), a second layer (19), and at least one intermediate layer (20) arranged between the first layer (18) and the second layer (19). The excitation coil (5) comprises a plurality of windings (29) applied to the first layer (18) and the second layer (19). The compensation winding (8) of the first receiving coil (6) is applied to the first intermediate layer (20), and the compensation winding (8) is arranged in a specific region in a vertical region between the winding (29) of the excitation coil (5) in the first layer (18) and the winding (29) of the excitation coil (5) in the second layer (19). The inductive position sensor device (1) according to 1. above is characterized by this. 3. The first receiving coil (6) is applied to the first intermediate layer (20) and the second intermediate layer (25) by its windings (8, 10, 11, 12). The inductive position sensor device (1) according to 1. or 2. above is characterized by this. 4. The second receiving coil (6) is applied to the first intermediate layer (20) and the second intermediate layer (25) by its windings (13, 14), and the second intermediate layer (25) is disposed between the first layer (18) and the second layer (19). The inductive position sensor device (1) according to any one of 1. to 3. above, characterized in that. 5. The windings (8, 10, 11, 12, 13, 14) of the first receiving coil (6) and the second receiving coil (7) each comprise a plurality of positive and negative windings (10, 11, 12; 13, 14), and these positive and negative windings (10, 11, 12; 13, 14) are surrounded diametrically by the winding (29) of the excitation coil (5). The inductive position sensor device (1) according to any one of 2. to 4. above, characterized in that. 6. The first receiving coil (6) is a cosine receiving coil. The inductive position sensor device (1) according to any one of 1. to 5. above, characterized in that. 7. The second receiving coil (7) is a sine receiving coil. The inductive position sensor device (1) according to any one of 1. to 6. above, characterized in that. 8. The excitation coil (5), the first receiving coil (6) and the second receiving coil (7) each comprise a connection portion (15; 16; 17) to an evaluation unit. The inductive position sensor device (1) according to any one of 1. to 7. above, characterized in that. 9. A brake system for an automobile, comprising a brake actuating device having a movable brake cylinder piston (27) and / or an electric motor having a drive shaft and an impeller (26), wherein the position encoder element (3) of the position sensor device (1) according to any one of 1. to 8. above is represented by the brake cylinder piston (27) or the impeller (26). Brake system.

Explanation of Signs

[0042] 1 Position sensor device 2 Position receiving device 3 Position encoder element 4 Coil assembly 5 Excitation coil 6 First receiving coil 7 Second receiving coil 8 Compensation winding 9 Printed circuit board 10 First positive winding of the first receiving coil 11 Negative winding of the first receiving coil 12 Second positive winding of the first receiving coil 13 Positive winding of the second receiving coil 14 Negative winding of the second receiving coil 15 Connection part of the excitation coil 16 Connection part of the first receiving coil 17 Connection part of the second receiving coil 18 First layer 19 Second layer 20 First intermediate layer 21 Excitation magnetic field 22 Blade 23 Blade recess 24 Sub-section 25 Second intermediate layer 26 Impeller 27 Cylinder piston 28 Fastening ring 29 Winding

Claims

1. An inductive position sensor device (1) for detecting the positional location of a position encoder element (3) having a position receiving device (2), wherein the position receiving device (2) comprises a printed circuit board (9) of a multilayer design and has a coil assembly (4), the coil assembly (4) comprising at least one excitation coil (5) and at least a first receiving coil (6) and a second receiving coil (7), the first receiving coil (6) and the second receiving coil (7) each comprising a plurality of windings (8, 10, 11, 12, 13, 14) at least partially surrounded by the excitation coil (5). In the inductive position sensor device (1), the first receiving coil (6) comprises a compensating winding (8) arranged in a specific region above and / or below at least a sub-section (24) of the excitation coil (5), and the printed circuit board (9) of the multilayer design comprises a first layer (18), a second layer (19), a first intermediate layer (20) and a second intermediate layer (25) arranged between the first layer (18) and the second layer (19), the excitation coil (5) comprising a plurality of windings (29) applied to the first layer (18) and the second layer (19), the compensating winding (8) of the first receiving coil (6) being applied to the first intermediate layer (20), and the compensating winding (8) being arranged in a specific region in a vertical region between the winding (29) of the excitation coil (5) of the first layer (18) and the winding (29) of the excitation coil (5) of the second layer (19). The inductive position sensor device (1) is characterized in that

2. The inductive position sensor device (1) according to claim 1, characterized in that the first receiving coil (6) is applied to the first intermediate layer (20) and the second intermediate layer (25) by its windings (8, 10, 11, 12).

3. The inductive position sensor device (1) according to claim 1, characterized in that the second receiving coil (7) is applied to the first intermediate layer (20) and the second intermediate layer (25) by its windings (13, 14).

4. The windings (8, 10, 11, 12, 13, 14) of the first receiving coil (6) and the second receiving coil (7) each comprise a plurality of positive and negative windings (10, 11, 12; 13, 14), and these positive and negative windings (10, 11, 12; 13, 14) are surrounded diametrically by the winding (29) of the exciting coil (5). The inductive position sensor device (1) according to claim 1, characterized in that.

5. The first receiving coil (6) is a cosine receiving coil. The inductive position sensor device (1) according to claim 1 or 4, characterized in that.

6. The second receiving coil (7) is a sine receiving coil. The inductive position sensor device (1) according to claim 1 or 4, characterized in that.

7. The exciting coil (5), the first receiving coil (6) and the second receiving coil (7) each comprise a connection part (15; 16; 17) to an evaluation unit. The inductive position sensor device (1) according to claim 1 or 4, characterized in that.

8. A brake system for an automobile, comprising a brake actuating device having a movable brake cylinder piston (27) and / or an electric motor having a drive shaft and an impeller (26), wherein the position encoder element (3) of the inductive position sensor device (1) according to claim 1 or 4 is represented by the movable brake cylinder piston (27) or the impeller (26). Brake system.

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