JP5347446B2 - Substrate type multilayer coil and displacement sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light and compact substrate type double layer coil for ensuring a desired inductance, and to provide a displacement sensor apparatus with the same. <P>SOLUTION: The substrate type double layer coil 1 includes: a double layer coil 3M having a plurality of layers including planar coils 3 spirally formed with conductive parts in the central line direction of a spiral; an insulating layer comprising a flexible printed circuit board 2 interposed between adjacent coils; and conductive paths 51-53 provided in the insulating layer, and connected in serial so as to make the turning direction of currents in all coils 3 to be identical. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a displacement sensor device that detects a displacement of a detection object, and more particularly to a coil structure of the sensor.

  In recent years, in the field of automobiles, information on loads acting on wheels has been required in order to perform operation control during traveling. In order to obtain such information, a displacement sensor device is provided in a wheel rolling bearing device (hub unit) (see, for example, Patent Document 1).

  In such a rolling bearing device, an inner shaft that is a movable raceway is rotatably supported by a fixed raceway on the vehicle body via a rolling element, and a wheel is attached to the inner shaft. The displacement sensor device is provided to face the outer periphery of the end portion of the inner shaft, and outputs the displacement of the inner shaft that occurs when a load is applied to the wheel as a change in inductance. And the signal processing circuit connected to these displacement sensor apparatuses produces | generates the signal which shows a displacement based on the change of an inductance, and provides the said signal to ECU (electronic control unit). Thereby, the ECU can determine the load acting on the wheel.

  As a sensor (detection unit) for detecting a change in inductance, a laminated steel sheet in which a coil is wound is used. Specifically, a set of a total of four coils wound every 90 degrees in the circumferential direction of the laminated steel sheet formed in a ring shape is provided as two sets in the axial direction. That is, as a whole, two laminated steel plates and eight coils are required. Such a sensor structure has a large volume and weight and a large number of components, so that the material cost is high and the number of assembly steps increases.

  On the other hand, there is also an inductor in which a spiral coil is formed on a plane such as a printed circuit board (see, for example, Patent Documents 2 and 3). Such a planar coil structure is expected to greatly contribute to light weight and compactness compared to a structure in which a coil is wound around a laminated steel sheet.

JP 2007-127253 A JP-T-2006-509189 (FIG. 1 etc.) Japanese Patent Laying-Open No. 2005-303106 (paragraph [0005])

However, in a planar coil inductor, the maximum diameter of the spiral increases as the number of turns increases. Therefore, if the outermost diameter is suppressed, a large number of turns cannot be secured, and the sensor sensitivity does not increase. Conversely, if priority is given to securing the number of turns in order to increase the sensor sensitivity, the spiral becomes larger and the area of the substrate increases.
In view of such conventional problems, an object of the present invention is to provide a substrate-type multilayer coil that is lightweight and compact and that can secure a desired inductance, and a displacement sensor device including the same.

The substrate-type multilayer coil of the present invention comprises a multilayer coil in which a planar coil formed by forming a conductive portion in a spiral shape is provided in multiple layers in the direction of the center line of the spiral, and a flexible printed circuit board, and is adjacent to it. An insulating layer interposed between the coils, and a conductive path provided in the insulating layer and connecting all the coils in series so that the current winding direction is the same, the multilayer coil is an adjacent coil The winding directions of the spirals are opposite to each other, and the conductive path is formed along a through hole provided in the insulating layer, and either the inner or outer winding end of the coil is connected to another adjacent All the coils are connected in series by connecting to the one winding end of the coil, and the through hole penetrates all the insulating layers, and the through hole is in one direction orthogonal to the center line direction. Lined up It is intended.

In the substrate-type multilayer coil configured as described above, by configuring the spiral coil in a multilayer, it is possible to secure a large number of turns and suppress an increase in the surface area where the coil is provided. .
In addition, since the insulating layer is formed of a flexible printed board, the entire substrate-type multilayer coil can be easily curved (typically cylindrical). Therefore, for example, it is suitable for constructing a sensor along the surface of a columnar or cylindrical object.

Further, in the above-mentioned substrate type multilayer coil, the multilayer coil has the spiral winding directions opposite to each other between adjacent coils, and the conductive path is formed along a through hole provided in the insulating layer. All the coils are connected in series by connecting either the inner or outer winding end to the one winding end of another adjacent coil .
In this way, the winding direction of the spirals between adjacent coils is opposite to each other, so that a current can be passed through two adjacent coils without changing the winding direction. For example, if current flows in from the outer winding end of one coil, the current goes to the center of the vortex, for example, right-handed, and when it reaches another adjacent coil, the current turns rightward to the outside of the vortex. Reach the outer winding end of the coil. Therefore, the current always flows in the clockwise direction, and the number of clockwise turns is accumulated. The same applies to the reverse direction.
Further, it is possible to connect a substantially shortest distance of the conductive path between adjacent contact coils.

Further, in the substrate type multilayer coil, the through holes penetrate all the insulating layers, and the through holes are arranged in one direction orthogonal to the center line direction .
Therefore, although the area number is increased when the multilayer coil is increasing through-holes aligned in said one direction occupied by the multilayer expands gradually in that direction, the other direction both perpendicular to the one direction and the center line direction Does not spread. Accordingly, in the other direction, a constant compact size can be obtained regardless of the number of multilayers.

On the other hand, the present invention is a displacement sensor device that detects the displacement of a metal detection object in a non-contact manner,
A planar coil formed by forming a conductive part in a spiral shape is provided in multiple layers in the direction of the center line of the spiral, and the spiral coil faces the detection object and between the adjacent coils. An insulating layer interposed in the insulating layer, a conductive path that is provided in the insulating layer and connects all the coils in series so that the current winding direction is the same, an inductance of the multilayer coil, the multilayer coil, and the detection And a signal processing circuit for extracting an output signal when an LC circuit constituted by a capacitance appearing between the object and an object is driven by an AC signal, and the multi-layer coil has a spiral direction between adjacent coils. The conductive path is formed along a through hole provided in the insulating layer, and the winding end of either one of the inner and outer sides of the coil is connected to the winding end of the other adjacent coil. Connect with All of the coils are connected in series by Rukoto, the through hole is intended to penetrate all of the insulating layer, the through-holes are those arranged in one direction perpendicular to the center line direction.
In the displacement sensor device configured as described above, it is possible to secure a large number of turns and suppress an increase in the surface area in which the coil is provided by configuring the spiral coil in multiple layers.

  ADVANTAGE OF THE INVENTION According to this invention, the board | substrate type multilayer coil which ensures lightweight and compact and desired inductance can be provided. Further, it is possible to provide a lightweight and compact displacement sensor device while ensuring the inductance necessary for the coil of the sensor in order to obtain a desired sensor sensitivity.

  FIG. 1 is a diagram for explaining the principle of a planar coil, which is a prerequisite element of the substrate type multilayer coil of the present invention. As shown in FIG. 2A, the planar coil 1p is provided with a coil 3 formed by forming a conductive portion in a spiral shape on a substrate, preferably on a flexible printed circuit board (FPC) 2. Such a planar coil 1p can be manufactured, for example, by etching from a flexible printed circuit board on which a metal foil such as copper or aluminum is adhered, leaving a spiral pattern. In addition, the edge part of the spiral center of the coil 3 can be derived | led-out to the back surface by a through hole, for example. The coil 3 has an inductance L that depends on the number of turns of the spiral (the number of times the spiral is wound), the cross-sectional area of the coil, the length of the coil, and the like. Is an element. Therefore, it is possible to obtain a desired inductance by securing the number of turns.

  FIG. 5B is a perspective view showing a state in which the planar coil 1p is brought close to and opposed to the displacement detection target 4; The detection object 4 is made of metal (for example, iron-based metal) and has conductivity. The inductance of the coil 3 is affected by the detection object 4. Further, with respect to the AC signal, a capacitance depending on the pattern area and the distance between them appears between the pattern of the coil 3 and the detection target 4. Therefore, such a planar coil 1p is equivalent to a parallel LC circuit as shown in FIG. Here, the values of the inductance L and the capacitance C vary depending on the gap between the detection object 4 and the planar coil 1p.

When the gap increases, both the inductance L and the capacitance C with respect to the AC signal decrease, and conversely, when the gap decreases, both the inductance L and the capacitance C increase. Therefore, the self-resonant frequency f (= 1 / (2π (L · C) ^1/2 )) of the LC circuit changes due to the change in the gap.
FIG. 2 is a graph showing an example of frequency characteristics of the LC circuit. The frequency characteristic is, for example, a solid curve that peaks at the self-resonant frequency f1, but when the self-resonant frequency decreases to f2, the frequency characteristic becomes a dashed curve. As a result, when the constant oscillation frequency f0 is supplied to the LC circuit, the output (amplitude) of the LC circuit changes from V1 to V2. In this way, a change in gap can be detected as a change in output.

Next, the board | substrate type multilayer coil 1 which concerns on one Embodiment of this invention is demonstrated. FIG. 3 is a perspective view showing the substrate type multilayer coil 1. Here, X, Y, and Z shown in the figure are three directions orthogonal to each other.
In the figure, a planar coil 3 formed by forming a conductive portion in a spiral shape on the XZ plane is provided in multiple layers (two layers) in the direction of the center line of the spiral (Y direction). A layer coil 3M is configured. A flexible printed circuit board 2 as an insulating layer is interposed between adjacent coils 3. A conductive path 5 is formed in the flexible printed board 2 along a through hole (not shown). The upper and lower coils 3 are connected to each other through the conductive path 5. In order to make the drawing easier to see, the two coils 3 are shown separated from each other up and down, but in reality, the two coils 3 are back to back with the thin flexible printed circuit board 2 interposed therebetween.

  The two coils 3 are spirals opposite to each other when viewed from the same direction (for example, above), but are wound in the same direction when viewed from the viewpoint of current. That is, if a current flows from the outer winding end of the upper coil 3, the current turns rightward toward the center of the vortex, and when reaching the lower coil 3, this time turns rightward toward the outside of the vortex. The outer winding end of the lower coil 3 is reached. Therefore, the current always flows in the clockwise direction, and the number of clockwise turns is accumulated. When the current flows in reverse, the current always flows counterclockwise and the number of counterclockwise turns is accumulated.

In this manner, the number of turns twice as large as that of one coil 3 can be ensured although the substrate-type multilayer coil 1 is extremely thin in the thickness direction (the direction of the center line of the spiral). Therefore, a desired inductance can be easily obtained. Moreover, the increase in the surface area in which a coil is provided can be suppressed by multilayering.
Furthermore, since the layers are connected by the conductive path 5 of the through hole, the length of the conductive path 5 is substantially the shortest distance and there is no waste. Further, since the centers of the spirals of the two coils 3 do not shift, it is difficult for the magnetic flux to cancel, and the inductance can be obtained without waste.

  On the other hand, since the two coils 3 are spirals opposite to each other and are not in the same form, the two coils 3 seen through the XZ plane have an overlapping portion and a non-overlapping portion, and this does not overlap. The presence of the part increases the pattern area as a whole as compared with one coil. Therefore, assuming that a metal object exists in the Y direction, when an AC signal is applied to the multilayer coil 3M, the capacitance that appears between the object is larger than that in the case of a single-layer coil. That is, the objective capacitance can be increased by forming the coil in multiple layers.

Next, a substrate type multilayer coil 1 according to another embodiment of the present invention will be described. FIG. 4 is a perspective view showing the substrate type multilayer coil 1. This configuration is a further development of the multi-layered substrate-type multi-layer coil 1 than in FIG.
In the figure, a planar coil 3 formed by forming a conductive portion in a spiral shape on the XZ plane is provided in multiple layers (four layers) in the direction of the center line of the spiral (Y direction). The coil 3M is configured. A flexible printed circuit board 2 as an insulating layer is interposed between adjacent coils 3. In the flexible printed circuit board 2, conductive paths 51, 52, and 53 are formed along the through holes h1, h2, and h3, respectively. The through holes h1 and h2 are arranged at a pitch P in one direction (Z direction in this example). Compared to FIG. 3, the dimension in the Z direction of the multilayer coil 3M as a whole is increased by the amount of the pitch P, but the dimension in the X direction is the same.

  Assuming that the coil 3 is the first to fourth layers in order from the top, the inner winding end of the first layer coil 3 and the inner winding end of the second layer coil 3 are connected to each other via a conductive path 51. Yes. The outer winding end of the second layer coil 3 and the outer winding end of the third layer coil 3 are connected to each other via a conductive path 53. The inner winding end of the third layer coil 3 and the inner winding end of the fourth layer coil 3 are connected to each other via a conductive path 52. Thus, a total of four layers of coils 3 are connected in series with each other.

Moreover, among the coils 3 in total of four layers, adjacent coils have the spiral winding directions reversed. That is, the first layer coil 3 and the second layer coil 3 are reversed in the spiral manner, and the second layer coil 3 and the third layer coil 3 are opposite in the spiral manner. In addition, the third layer of coil 3 and the fourth layer of coil 3 are opposite to each other in how the spirals are wound.
In order to make the figure easy to see, the four coils 3 are shown as being separated from each other up and down, but in reality, the flexible printed circuit board 2 is sandwiched between two adjacent coils so that the board is thin as a whole. A multi-layer coil 1 is configured.

The four coils 3 are spirals that are alternately reversed when viewed from the same direction (for example, from above), but are wound in the same direction when viewed from the viewpoint of current. That is, if a current flows from the outer winding end of the first layer coil 3, the current turns rightward toward the center of the vortex and passes through the conductive path 51 to reach the second layer coil 3. Goes rightward to the outside of the vortex and reaches the outer winding end of the coil 3 of the second layer. Subsequently, when the current that has reached the outer winding end of the third layer coil 3 through the conductive path 53 reaches the center of the vortex in a right-handed direction and reaches the fourth layer coil 3 through the conductive path 52. This time, it goes to the outside of the vortex to the right and reaches the outer winding end of the coil 3 of the fourth layer.
Therefore, the current always flows in the clockwise direction, and the number of clockwise turns is accumulated. When the current flows in reverse, the current always flows counterclockwise and the number of counterclockwise turns is accumulated.

In this way, the number of turns four times that of one coil 3 can be secured even though the substrate-type multilayer coil 1 is extremely thin in the thickness direction (the direction of the center line of the spiral). Therefore, a desired inductance can be easily obtained. Moreover, the increase in the surface area in which a coil is provided can be suppressed by multilayering.
Furthermore, since the layers are connected by the conductive path 5 of the through hole, the length of the conductive path 5 is substantially the shortest distance and there is no waste. Further, since the spiral centers of the four coils 3 are hardly displaced, it is difficult to cancel the magnetic flux, and a large inductance can be obtained without waste.

  On the other hand, the four coils 3 are alternately reversed spirals, and the positions of the two winding ends are not the same even if every other spiral is the same spiral. That is, the four coils 3 are not in the same form. Therefore, the four coils 3 seen through the XZ plane have an overlapping portion and a non-overlapping portion. As a result, the pattern area is larger than that of one coil as a whole. Will increase. For this reason, as in the case of the configuration of FIG. 3, the objective capacitance can be increased by the multilayering of the coil.

In FIG. 4, the coil 3 having four layers is merely an example, and a multilayer may be used as necessary, or an odd number of layers may be used. Basically, it is sufficient if there are two or more layers. In order to make both winding ends of the multilayer coil as a whole outside the spiral, an even number layer based on the configuration of FIG. 4 may be used.
In this case, as the number of multilayers increases, the number of through holes arranged in the Z direction increases and the area occupied by the multilayer coil 3M gradually expands in that direction, but does not expand in the X direction. Therefore, in the X direction, a constant compact size can be obtained regardless of the number of multilayers.

  Note that there are a through-hole type and a non-through-type in the through hole, and FIG. 4 is drawn so that the through holes h1, h2, and h3 are not through. However, in practice, through-holes are common. FIG. 5 is a perspective view showing a substrate-type multilayer coil similar to that in FIG. In this case, each through hole exists over all four layers.

4 and 5, the through holes are used based on the configuration in which the spiral winding method is reversed in order, but in principle, all the coils are connected in series so that the current winding directions are the same. I can do it.
For example, FIG. 11 is a perspective view showing a substrate-type multilayer coil 1 in which coils 3 that are spirals of the same winding method are configured in four layers. In this case, the conductive path 5 needs to connect the inner winding end of one coil 3 and the outer winding end of another adjacent coil 3. Absent. However, for example, if an extra layer including the conductive path 5 (a total of three layers in this example) is prepared, the total number of layers increases (4 + 3 layers), but this is a feasible configuration.

  The substrate-type multilayer coil 1 as described above can be easily curved (typically cylindrical) by using the flexible printed circuit board 2. Therefore, for example, it is suitable for constructing a sensor along the surface of a columnar or cylindrical object.

Next, a displacement sensor device according to an embodiment of the present invention using the substrate type multilayer coil 1 as described above will be described.
FIG. 6A is a development view of the substrate type sensor 10 used in the displacement sensor device. In this substrate type sensor 10, a total of eight multi-layer coils 3 </ b> M (symbols common to each unit) are provided in two stages on the flexible printed circuit board 2. In addition, although the multilayer coil 3M is simplified and drawn like a concentric circle in the figure, it is actually a spiral as shown in FIGS. 3 and 4 (the same applies hereinafter).

Here, the individual codes for the coils correspond to the X direction and Z direction orthogonal to the Y direction and orthogonal to each other when the axial direction of the rotating body described later is the Y direction. The combination number, +,-represents a set in the X and Z directions. That is, the combination of coils for detecting displacement is as follows.
X-direction displacement: (X1 +, X1-), (X2 +, X2-)
Z-direction displacement: (Z1 +, Z1-), (Z2 +, Z2-)
Two winding ends (not shown) in each multilayer coil 3M are led to the terminal electrode portion 2a through the conductive paths 6 on both the front and back surfaces of the flexible printed circuit board 2.

  When such a substrate-type sensor 10 is rolled into a cylindrical shape, it becomes as shown in (b), and the coils X1 + and X1-, and X2 + and X2- each exist in pairs in the X direction. . In addition, the coils Z1 + and Z1-, and Z2 + and Z2- each form a set of two in the Z direction. In addition, each of the four coils on the upper side and the lower side is arranged every 90 degrees in the circumferential direction.

  FIG. 7 is a perspective view showing a state in which the flexible printed circuit board 2 in a rolled state is supported and attached to the inner peripheral surface of the cylindrical support portion 11 so as to maintain the cylindrical shape. In order to fix the flexible printed circuit board 2 to the inner peripheral surface, for example, a heat-resistant resin adhesive can be used. The support portion 11 may be made of resin, but here it is made of metal. In the case of being made of metal, the mechanical strength can be easily ensured, so that the support portion can be made thinner than that of resin. This contributes to downsizing. Even when the support portion is made of metal, it was confirmed that the displacement detection is not affected by driving the LC circuit with a high-frequency signal (100 kHz to 500 kHz).

  On the inner side of the flexible printed circuit board 2 fixed to the inner peripheral surface of the support portion 11, a rotating body 12 as a detection target is inserted with a small radial gap. The rotating body 12 is, for example, an automobile axle. In that case, the support portion 11 is attached to a fixed wheel of the rolling bearing device, and a rotating body (axle) 12 is attached to the movable wheel. And said clearance gap is maintained by the rolling bearing apparatus.

  FIG. 8A shows a state where the support 11 is omitted and the rotating body 12 is inserted inside the flexible printed circuit board 2. (B) is the figure which looked at this from the axial direction of the rotary body 12. FIG. There is a radial gap (for example, about 3 mm) between the flexible printed circuit board 2 and the surface of the rotating body 12, and the above-described inductance L and capacitance C change due to the change in the gap. Accordingly, the radial displacement of the axle that occurs when a load is applied to the wheel can be detected as the change in output described above.

  FIG. 9 is a circuit diagram illustrating an example of a circuit configuration of the displacement sensor device 20. The displacement sensor device 20 includes a signal processing circuit 17 in addition to the multilayer coil 3M mounted on the substrate type sensor 10. Each coil is equivalently an LC circuit as described above, and an AC signal having a predetermined oscillation frequency f0 is supplied from the oscillation circuit 13 via the resistor 14. The output of the LC circuit is input to the differential amplifier circuit 16 through a buffer circuit (voltage follower circuit) 15 that performs impedance conversion.

The differential amplifier circuit 16 linearizes and amplifies the signal by taking the difference between the signal voltages from the two LC circuits forming a pair. By the linearization, the displacement of the rotating body 12 in the radial direction can be accurately detected. That is, it is possible to accurately detect the displacement of the rotating body 12 in the radial direction by providing a pair of two coils in a direction orthogonal to the axial direction and taking a difference in output. The signals after differential amplification are output as two outputs (X1, X2) in the X direction and two outputs (Z1, Z2) in the Z direction. Based on these four outputs, the ECU (not shown) calculates the load acting on the wheels. Further, the moment load can be obtained based on the two outputs in the same direction.
The signal processing circuit 17 is provided separately from the board-type sensor 10, but can be mounted in an empty space of the flexible printed board 2.

As described above, according to the displacement sensor device 20 according to the above-described embodiment, the inductance necessary for the coil of the sensor in order to obtain a desired sensor sensitivity by using the substrate-type multilayer coil 3M as a displacement detection sensor. Thus, a lightweight and compact displacement sensor device can be provided.
Moreover, the flexible printed circuit board 2 is easily deformable and can be freely brought close to the surface of the rotating body 12. Since the capacitance appears between the conductive portion of the multilayer coil 3M and the rotating body 12 due to the proximity, the LC circuit can be configured without separately preparing a capacitor as a circuit component.
In addition, a necessary number of multilayer coils 3M can be provided on one substrate, whereby the functions necessary for only one flexible printed circuit board 2 can be integrated.

The displacement sensor device 20 according to each of the above embodiments can be mounted on, for example, a rolling bearing device that rotatably supports a wheel of an automobile.
FIG. 10 is a cross-sectional view of a hub unit which is a kind of rolling bearing device. The hub unit 100 is attached to a vehicle, and in the attached state, the right side in FIG. 10 is the outer side of the vehicle (the outside of the vehicle), and the left side is the inner side of the vehicle (the inside of the vehicle). In FIG. 10, the direction along the central axis C of the hub unit 100 is defined as the Y direction, the direction perpendicular to the paper surface orthogonal thereto is defined as the X direction, and the vertical direction perpendicular to both the Y direction and the X direction is defined as the Z direction. To do. Therefore, in a state where the hub unit 100 is attached to the automobile, the X direction is the front-rear horizontal direction of the wheel, the Y direction is the left-right horizontal direction (axial direction) of the wheel, and the Z direction is the vertical direction.

  The hub unit 100 includes an outer ring 101, an inner shaft 102, an inner ring member 103, a nut 104, and a rolling element 105 as main structural parts. The outer ring 101 has a cylindrical portion 101a and a flange portion 101b extending radially outward from a part of the outer peripheral surface of the cylindrical portion 101a. The flange portion 101b is fixed to a fixing member (not shown) on the vehicle body side, whereby the hub unit 100 is fixed to the vehicle body. The inner shaft 102 has a main shaft portion 102a that is inserted into the outer ring 101, and a flange portion 102b that extends on the outer side of the vehicle and extends radially outward. The flange portion 102b serves as a mounting portion for a wheel or a brake disk of the wheel. The main shaft portion 102a is a portion corresponding to the above-described rotating body 12 (FIG. 7).

A cylindrical inner ring member 103 is fitted on the inner side of the inner shaft 102 on the vehicle inner side, and a nut 104 is screwed onto a male screw portion 102d formed on the end of the inner shaft 102, whereby the inner ring member 103 is fitted. Is fixed to the inner shaft 102. The rolling element 105 has a double-row configuration including a plurality of balls arranged in the circumferential direction. The balls in each row are held at predetermined intervals in the circumferential direction by a cage (not shown).
In the hub unit 100, the outer ring 101 is a fixed race that is fixed to a fixing member on the vehicle body side. Further, the inner shaft 102 and the inner ring member 103 are rotating raceways that are rotatably supported by the outer ring 101 via rolling elements 105. The outer ring 101, the inner shaft 102, and the inner ring member 103 are arranged coaxially (center axis C).

In the hub unit 100 configured in this manner, the displacement of the inner shaft 102 can be detected by mounting the substrate type sensor 10 of FIG. 7 together with the support portion 11 on the inner peripheral surface of the outer ring 101.
In this case, it is possible to provide a compact hub unit 100 while mounting the substrate type sensor 10 or the like. That is, the substrate type sensor can be mounted in a narrow place between the inner and outer rings of the rolling bearing device, which could not be mounted conventionally.

In addition, the board | substrate type multilayer coil 1 of said each embodiment can be used as an inductor of various uses besides a displacement sensor.
Further, the displacement sensor device 20 of the above embodiment can be used not only for the rolling bearing device but also for detecting the displacement of various devices. If the target is detected periodically, speed detection and rotation speed detection can be performed based on the displacement detection.
In addition, the detection target in the displacement sensor device is not limited to a rotating body, and an object that causes displacement in various devices such as an axial-type device and a reciprocating device can be detected.

It is a figure explaining the principle of the plane coil used as the fundamental element of the board | substrate type multilayer coil of this invention. It is a graph which shows an example of the frequency characteristic of LC circuit. It is a perspective view showing a substrate type multilayer coil concerning one embodiment of the present invention. It is a perspective view which shows the board | substrate type multilayer coil which concerns on other embodiment. FIG. 5 is a perspective view showing a substrate-type multilayer coil similar to that in FIG. 4 on the assumption of the existence of a through-through hole. It is the expanded view of the board | substrate type sensor used for the displacement sensor apparatus which concerns on one Embodiment of this invention, and the perspective view of the state rounded to the cylindrical shape. It is a perspective view which shows the state which attaches the flexible printed circuit board of the rolled state on the internal peripheral surface of a cylindrical support part. (A) abbreviate | omits illustration of a support part and shows the state by which the rotary body is penetrated inside the flexible printed circuit board, (b) is the figure which looked at this from the axial direction of the rotary body. It is a circuit diagram which shows an example of the circuit structure of a displacement sensor apparatus. It is sectional drawing of the hub unit which is a kind of rolling bearing apparatus. It is a perspective view which shows the board | substrate type multilayer coil which comprised the coil which is the spiral of the same winding method as 4 layers as further embodiment of a board | substrate type multilayer coil.

Explanation of symbols

1 PCB multilayer coil 2 Flexible printed circuit board (insulating layer)
3 Coil 3M Multi-layer coil 5 Conductive path 12 Rotating body (detection target)
17 Signal processing circuit 20 Displacement sensor device 51-53 Conductive path h1, h2, h3 Through hole

Claims (2)

A multilayer coil in which a planar coil formed by forming a conductive portion in a spiral shape is provided in multiple layers in the direction of the center line of the spiral;
An insulating layer that is configured by a flexible printed circuit board and is interposed between the adjacent coils; and a conductive path that is provided in the insulating layer and that connects all the coils in series so that the current winding direction is the same .
In the multilayer coil, adjacent coils have mutually opposite spiral winding directions,
The conductive path is formed along a through-hole provided in the insulating layer, and the winding end of either the inner or outer side of the coil is connected to the one winding end of another adjacent coil. All the coils are connected in series,
The substrate-type multilayer coil , wherein the through holes penetrate all the insulating layers, and the through holes are arranged in one direction orthogonal to the center line direction . A displacement sensor device for detecting a displacement of a metal detection object in a non-contact manner,
A coil formed by forming a conductive portion in a spiral shape in a multilayer in the direction of the center line of the spiral, and a multilayer coil in which the spiral surface faces the detection object;
An insulating layer interposed between adjacent coils;
A conductive path provided in the insulating layer and connecting all the coils in series so that the current winding direction is the same;
A signal processing circuit that extracts an output signal when an LC circuit constituted by an inductance of the multilayer coil and a capacitance appearing between the multilayer coil and the detection object is driven by an AC signal ;
In the multilayer coil, adjacent coils have mutually opposite spiral winding directions,
The conductive path is formed along a through-hole provided in the insulating layer, and the winding end of either the inner or outer side of the coil is connected to the one winding end of another adjacent coil. All the coils are connected in series,
The through-hole penetrates all the insulating layers, and the through-hole is arranged in one direction orthogonal to the center line direction .

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