JP3839451B2 - Position detection device - Google Patents

Description

  The present invention relates to a position detection device (hereinafter referred to as a cordless position detection device) that does not require wiring cords for power supply or signal transmission from a fixed portion to a movable portion side.

  Rotation position detection devices include light transmission encoders, light reflection encoders, rotary transformer type resolvers, variable reluctance type resolvers, gear detectors that detect rotational positions of gears using a magnetoresistive element, etc. Although detection devices have been put into practical use, there are problems such as being vulnerable to dust, low resolution, and expensive.

  For example, as described in Japanese Patent No. 2513683, the linear position detection device uses an electromagnetic induction type cordless position detection device as a part of the coordinate input device, but cannot detect the position in real time. It is not suitable for machine positioning devices.

  As a cordless position detector, a variable reluctance linear resolver has been proposed as described in, for example, Japanese Patent Application Laid-Open No. 2000-314604, but a large number of core magnetic poles and windings corresponding to a detection length are provided on the fixed part side. Therefore, it is expensive for mass production.

  As a type that detects the rotational position, for example, a substrate type resolver as described in JP-A-2001-314069 is known. The resolver described in this document includes a stator substrate (1) on which a stator sin winding pattern (20) and a stator cos winding pattern (21) are formed, and the stator substrate facing the stator substrate (1). (1) is a substrate type resolver comprising a rotor substrate (5) that is rotatably arranged with a gap and a rotor winding pattern (30) provided on the rotor substrate (5). (1) consists of a configuration in which an excitation winding pattern (4) formed in a ring shape is disposed at the outer peripheral position of the stator sin winding pattern (20) and the stator cos winding pattern (21). Is a substrate type resolver. The rotor winding pattern (30) is connected or directly short-circuited at both ends by a capacitor (C), and the magnetomotive force generated from the rotor winding pattern (30) is substantially sin-wave. Is formed.

  However, since the excitation winding pattern (4) of the stator substrate described in this document is formed in a ring shape at the outer peripheral position of the sin winding pattern (20) and the stator cos winding pattern (21), the excitation winding pattern (4) The magnetic field strength is low, and the rotor winding pattern (30) is composed of a pair of forward and reverse windings, and the induced power due to the excitation winding pattern (4) of the rotor winding pattern (30) is low. Therefore, it is difficult to improve detection accuracy.

Further, JP-A-8-313295 discloses a transducer read head 100 having a transmitter winding 102 and a receiver winding 104 composed of loops 106 and 108 as a linear position detecting device. . However, according to the operating principle of the transducer described in this document, the excitation transmitter winding is formed in a loop around the receiver winding for detection. The magnetic flux density is insufficient, the magnetic coupling with the receiver winding is insufficient, and it is difficult to improve noise resistance and improve detection accuracy. In addition, since the eddy current of the metal piece is used, the induced power due to electromagnetic induction is small, which is disadvantageous in terms of noise resistance and detection accuracy.
Japanese Patent No. 2513683 JP 2000-314604 A JP 2001-314069 A JP-A-8-313295

  An object of the present invention is a position detection device (hereinafter referred to as a cordless position detection device) that does not require power supply from the fixed portion to the movable portion side or wiring cords for signal transmission, and has a high detection response speed. It is an object of the present invention to provide an electromagnetic induction type cordless position detection device that can be reduced in size and thickness, is inexpensive, and is useful for highly accurate linear position detection and rotational position detection.

That is, the above object is achieved by the following configuration of the present invention.
(1) An exciting coil formed on the first plane by being wound at least in a spiral shape for 2 t or more;
A detection coil having one or more pairs of coil units formed on the second plane so that forward winding and reverse winding alternately appear in one pitch unit in the same direction as at least the excitation coil;
A resonance coil having at least a resonance capacitor connected in parallel on the third plane;
At least the excitation coil in the first plane and the detection coil in the second plane have magnetic coupling;
The third plane is spaced apart from the first plane and the second plane via a space, and is freely movable in a specific direction in a detection coil forming region serving as a detection region. And / or the detection coil and the resonance coil can be magnetically coupled,
A position detection device that obtains a position detection voltage from the detection coil according to the position of the resonance coil.
(2) The excitation coil on the first plane and the detection coil on the second plane are formed so as to extend in one direction, and the third plane moves so as to slide in this formation region. Position detector.
(3) The position detection according to (1) above, wherein the excitation coil on the first plane and the detection coil on the second plane are formed rotationally symmetrically, and the third plane moves so as to rotate in this formation region. apparatus.
(4) The position detection device according to any one of (1) to (3), wherein the excitation coil and the detection coil are formed by connecting discontinuous spiral coils in series.
(5) The position detection device according to any one of (1) to (4), wherein the resonance capacitor portion of the resonance coil is short-circuited.
(6) The position detection device according to any one of (1) to (5), wherein the first plane and the second plane are configured by a laminated substrate.

  According to the present invention, an electro-magnetic circuit can be configured only by a printed board and a capacitor having no iron core or windings, so that an inexpensive, small and thin cordless position detecting device can be realized. Further, the excitation coil and the detection coil each form a plurality of loops and are strongly magnetically coupled, so that a high-output cordless position detection device can be realized with a simple configuration. In addition, since a mechanism for canceling external noise is provided in the detection loop, a cordless position detection device that is resistant to noise can be realized.

  The position detection device of the present invention includes an excitation coil formed on a first plane and wound at least 2 t in a spiral shape, and at least one pitch unit in the same direction as the excitation coil on the second plane. A detection coil having one or two or more units of a pair of coil units formed so that forward winding and reverse winding appear alternately; and a resonance coil in which at least a resonance capacitor is connected in parallel on the third plane; And at least the excitation coil on the first plane and the detection coil on the second plane have magnetic coupling, and the third plane is separated from the first plane and the second plane via a space. In addition, the detection coil can be freely moved in a specific direction in the detection coil forming region, and the excitation coil and / or the detection coil and the resonance coil can be magnetically coupled depending on the moving position. Ri is intended to obtain the position detection voltage from the detection coil according to the position of the resonance coil.

  Here, the first plane, the second plane, and the third plane do not need to be planes defined in terms of geometry, and have a certain thickness that can accommodate a conductor pattern formed on each plane. And a plate-like structure composed of front and back sides as necessary. More specifically, it is a resin plate-like body capable of forming an electronic circuit, and a material used for a prepreg, a printed board or the like is preferable. The circuit pattern can be easily configured by patterning a metal foil such as a copper foil or an aluminum foil. The first plane, the second plane, and the third plane are usually arranged in this order in the direction perpendicular to the plane, and the first plane and the second plane may be stacked. The third plane is spaced apart from these planes.

  The excitation coil forms a magnetic field for generating an electromotive force from the detection coil by the resonance coil. The exciting coil is formed of, for example, a spiral coil wound for 2 t (turns) or more. The exciting coil is formed and arranged along the measurement region of the position detection device. The loop to be formed is formed in a long and spiral shape when measuring a linearly extending region, and is formed in a shape corresponding to the rotating region when detecting a rotational position. Further, it is formed in a size and a number of loops that cover the measurement region and can provide a sufficient excitation magnetic field to the detection coil. For this reason, when the exciting coil extends linearly, it is formed longer than the detection coil by a length that does not give the detection coil the influence of magnetic flux imbalance at the folding positions at both ends. The excitation coil can be formed on the front and back surfaces of a printed circuit board or the like that forms a plane as described above.

  The detection coil generates a predetermined detection signal from the balance between the magnetic field from the excitation coil and the magnetic field generated by the resonance coil. This detection signal is normally output as an alternating voltage. The detection coil is formed, for example, by connecting in series a normal winding and a reverse winding wound for 2 t (turns) or more, and the normal winding and the reverse winding, or the normal phase and the reverse phase are alternately arranged in the coil forming direction. It has come to occur. The exciting coil is formed and arranged along the measurement region of the position detection device. The formed loop is formed so that the normal winding and the reverse winding alternately appear in one pitch unit corresponding to at least one loop, and the number of loops that can cover the measurement area with one set of forward and reverse loops as a minimum unit. Only formed. The detection coil and the excitation coil are normally fixed, and the positional relationship between the excitation coil and the detection coil is also fixed. The detection coil can also be formed on the front and back surfaces of a printed circuit board or the like that forms a plane as described above. Moreover, you may form an exciting coil and a detection coil in the printed circuit board on which the some structure layer was laminated | stacked.

  The resonance coil receives a magnetic field from the exciting coil, generates an electromotive force therein, resonates with a resonance capacitor connected in parallel, and generates a magnetic field generated from the resonance current or the power itself. Note that the resonance capacitor can be omitted. This resonance coil can be constituted by connecting a resonance capacitor in parallel with a spiral coil, for example. The resonance coil has a single unit of either a normal winding loop or a reverse winding loop as a basic unit, and is usually composed of only this basic unit. However, a loop can be further added if necessary.

  Furthermore, the first plane, the second plane, and the third plane may be shaped corresponding to the rotating body, and the excitation coil, detection coil, and resonance coil may be formed rotationally symmetrically. By setting it as such a shape, the rotation position of a rotary body is detectable.

[First embodiment]
Next, the position detection apparatus of the present invention will be described more specifically with reference to the drawings. FIG. 1 is a plan view showing a basic structure (also referred to as a first aspect) of a position detection device of the present invention.

  In the figure, an excitation loop pattern 4 serving as an excitation coil is formed on the first plane 1. The excitation loop pattern 4 is formed on the surface of the base 11, and in this example, it is a horizontally long square spiral pattern. Specifically, the width (vertical) direction is folded back with the widths s1, s2, and s3, and the longitudinal (horizontal) direction is a length p3 or more (s1) at which the influence of the vertical excitation current on the detection loop described later can be ignored. The above is formed from a rectangular spiral loop pattern that is folded back. The excitation loop pattern 4 in this example is a three-fold loop, but may be configured by one or several tens of loops depending on the excitation power supply and the current capacity of the coil pattern. In the figure, the solid line represents the pattern on the substrate surface side, the broken line represents the pattern on the back surface side, and both are connected by a conductor penetrating the substrate such as a through hole or a via hole (the same applies hereinafter).

  An excitation power source 7 is connected to the excitation loop pattern 4 via nodes n1 and n2, and an alternating current having a predetermined frequency and voltage is supplied. The frequency of the excitation power supply is not particularly limited, but is preferably 100 K to 1000 KHz, and the excitation current is preferably about 10 to 100 mA.

  A detection loop pattern 5 serving as a detection coil is formed on the second plane 2. This detection loop pattern 5 is formed on the surface of the base 12 and is composed of coil patterns c1, c2,... Cn-1, cn having the same shape. These coil patterns c1, c2,..., Cn-1, cn are arranged side by side in the longitudinal (transverse) direction at a pitch of 1p, and the winding direction of one of the coils c2, cn adjacent to each other by the pattern indicated by the dotted line Are connected in series so as to be opposite to the winding direction of the other coils c1 and cn-1, and this series circuit is connected to the detection terminals n3 and n4. The shape of c1, c2,..., cn-1, cn is a spiral shape that is folded back in the width direction with the width of s1, s2, and the longitudinal direction is folded back at p1, p2.

  In addition, the detection loop pattern of this example is composed of n coil patterns of the same shape, which are normally even numbers, but may be composed of an even number of coil patterns according to the detection length.

  The first plane 1 and the second plane 2 are normally fixed, and the positional relationship of the second plane 2 with respect to the first plane 1 is also fixed. The first plane 1 and the second plane 2 can be formed by separately preparing a base, but can also be integrated. When integrated, the first plane 1 and the second plane 2 may be stacked or stacked, but a short circuit between the excitation loop pattern 4 and the detection loop pattern 5 formed on these planes is prevented. Therefore, it is necessary to provide an insulating layer between them. This insulating layer may be air, but is preferably a laminate using the same material as the base constituting the first plane 1 and the second plane 2.

  Specifically, as shown in FIG. 2, between the first substrate 11 constituting the first plane 1 and the second substrate 12 constituting the second plane 2, these substrates 11, An insulating substrate 24 made of the same material as 12 is provided to form a laminated substrate. Here, the first substrate 11 has a conductor layer 14 that forms the excitation loop pattern 4 arranged vertically, and the second substrate 12 has a conductor layer 15 that forms the detection loop pattern 5 arranged vertically. Yes. The insulating substrate 24 prevents the conductor layers 14 and 15 from being short-circuited. Lamination of the substrate can be easily performed by a known method such as thermocompression bonding.

  A resonance loop pattern 6 serving as a resonance coil is formed on the third plane 3. Similarly to the detection loop pattern 5, the resonance loop pattern 6 is formed in a spiral shape having a size P1 indicated by a solid line, folded in the width (vertical) direction with the width of s1 and s2, and folded in the longitudinal direction with p1 and p2. ing. Further, both ends of the resonance loop pattern 6 are connected to the resonance capacitor C1.

  The capacitance of the resonance capacitor varies depending on the excitation frequency and the inductance of the resonance coil, but is preferably about 0.01 to 0.1 μF, for example.

  The third plane 3 is either the first plane 1 or the second plane 2, or both are arranged apart from each other in the stacking direction. And it can slide or move in parallel with respect to these planes freely in the measurement region, that is, the formation region of the excitation coil or the detection coil. Specifically, for example, as shown in FIG. 2, a third body 9 having conductor layers 16 on the upper and lower sides of the substrate 13 at positions separated from each other in the stacking direction of the stacked body 9 having the first plane and the second plane. A plane 3 is arranged. Although a mechanism for sliding or moving is omitted in this specification, it can be easily achieved by a known method in this type of field.

Next, the operation of the position detection apparatus of this illustrated example will be described.
First, it is assumed that the third plane 3 does not exist or exists outside the measurement region. Now, when the excitation current i flows from the excitation power source 7 to the excitation loop 4 in the direction of the solid line arrow, an electromotive force is generated in the detection loop pattern 5 in the direction of the solid line arrow in the figure, but the loop c1, the loop c2, and the loop cn- The electromotive forces of 1 and the loop cn cancel each other, and no AC induced detection voltage (hereinafter referred to as a detection voltage) is generated between the nodes n3 and n4 which are detection ends. Even if the exciting current i flows in the reverse direction as shown by the dotted line, the electromotive forces of the loop c1 and the loop c2 and the loop cn-1 and the loop cn are canceled out in the same manner, so that the detected voltage is similarly between the nodes n3 and n4. Does not occur.

  Note that such a canceling action of the detection loop similarly acts on the external common noise, so that a position detection device that is extremely resistant to noise can be realized.

  Next, as shown in the cross-sectional views of FIG. 1 and FIG. 2, the third plane 3 is on the starting end side of the excitation loop pattern 4, and is arranged with a gap from the first and second planes 1 and 2, It is assumed that the loop area Cr of the resonance loop pattern 6 overlaps the loop area of the excitation loop pattern 4 (inside from p3).

  At this time, as shown in FIG. 1, when the excitation current i flows in the excitation loop pattern 4 in the direction of the solid line arrow, the magnetic flux in the loop area of the excitation loop pattern 4 flows in the loop area Cr of the resonance loop pattern 6 on the third plane 3. Are interlinked and an electromotive force is generated in the direction of the solid arrow. On the other hand, when the excitation current i flows in the direction of the dotted arrow, the direction of the magnetic flux in the loop area Cr is reversed, and similarly, an electromotive force in the direction of the dotted arrow is generated in the resonance loop pattern 6 by the electromagnetic induction operation.

  Since the direction of the excitation current to which alternating current is applied changes periodically, the alternating current also flows through the resonance loop pattern 6 and resonates by the resonance capacitor C. When an appropriate constant capacitor is selected as the resonance capacitor C, the opposing interval is narrowed, and the position of the width s1 of the resonance loop pattern 6 and the excitation loop pattern 4 is matched to strengthen the magnetic coupling, a large resonance current flows. Since the resonance loop pattern 6 is also magnetically coupled to the detection loop pattern, a detection voltage is induced in the detection loop pattern 5.

  At the origin og position of the third plane 3 as shown in FIGS. 1 and 2, the loop area Cr of the resonance loop pattern 6 is magnetically coupled only to the loop area C1 of the detection loop pattern 5 and thus induced. The output voltage is output as detection voltage to the nodes n3 and n4 without being canceled. Assuming that the detection voltage having the same phase as the excitation power source is the positive phase and the detection voltage having a phase different by 180 ° is the negative phase detection voltage, the maximum detection voltage of the positive phase at the current position of the third plane 3 as shown in FIG. Is induced and output to nodes n3 and n4.

  Next, when the third plane 3 moves in the right direction on the drawing in the right direction and the width s1 direction as it is and is translated while maintaining the same interval, the loop area Cr of the resonance loop pattern 6 is the loop area C1 and the loop area C2 according to the movement. Both are magnetically coupled. For this reason, the magnetic flux that electromagnetically induces the detection loop pattern decreases, and the detection voltage also decreases.

  Further, when the third plane 3 moves to the right from the origin og to the position of 1 / 2P, the loop area Cr of the resonance loop pattern 6 is magnetically coupled equally to the loop areas C1 and C2, and therefore the occurrence in the loop areas C1 and C2 is caused. The power is canceled and the detection voltage becomes zero.

  When the third plane 3 moves further to the right, the loop area Cr of the resonance loop pattern 6 becomes more magnetically coupled to the loop area C2 than the loop area C1 as the movement is made, and a reverse phase detection voltage is induced to move to the right. It grows as you follow.

  At the position where the third plane 3 has moved 1P from the origin og, the loop area Cr is magnetically coupled only with the loop area C2, so that a maximum detection voltage in reverse phase is output.

  In this way, when the third plane 3 is provided with a predetermined distance from the first plane 1 and the second plane 2 and moved parallel to each other, the movement of the third plane is performed as shown in FIG. Corresponding to the quantity, a detection voltage that changes sinusoidally in a cycle 2P is output. That is, the detection loop pattern 5 cannot be AC-excited directly by the excitation loop pattern 4, but the detection loop pattern 4 can be AC-excited indirectly via the resonance loop pattern 6. Note that the amplitude of the detection voltage can be increased by arranging a plurality of resonance loops having the same winding direction on the third plane 3 at a pitch of 2p.

  Further, when both ends of the resonance capacitor C are short-circuited, an eddy current flows instead of the resonance current, so that the detection loop pattern corresponds to the movement of the movable printed board which is the third plane 3 as in the case of the resonance current. The magnetic flux in the five loop areas C1 to Cn changes, and a detection voltage that changes like a sine wave as in FIG. Furthermore, when a metal conductor plate having the same shape as the loop area Cr of the resonance loop pattern 6 is formed and arranged at a pitch P instead of the coil in the loop area, an eddy current flows through the metal conductor plate, and similarly changes into a sine wave shape. Detection voltage is output.

  As described above, it can be seen that this basic operation loop can detect a voltage that changes in a sine wave shape corresponding to the linear movement of the movable part without any wiring cords from the fixed part to the movable part.

[Second embodiment]
Next, the second aspect of the present invention will be described. FIG. 4 is a plan view showing a second aspect of the present invention. In this embodiment, the excitation loop pattern 4 is formed in double on the front and back of the base 11, and two detection loop patterns 5 are prepared, that is, an A phase detection loop pattern 4a and a B phase detection loop pattern 4b, and an AB phase detection is performed. It is a type. Other constituent elements are the same as those of the first embodiment shown in FIG. 1, and the same constituent elements are denoted by the same reference numerals and description thereof is omitted.

  As shown in the figure, the excitation loop pattern 4 on the first plane 1 is folded on the base 11 in the width (longitudinal) direction and with the widths s1, s2, and s3. This is a rectangular and spiral loop pattern that is folded back with a length p3 or more (s1 or more) that can ignore the influence on detection loop patterns 5a and 5b, which will be described later, and a loop represented by a solid line is represented by a dotted line on the surface. It is formed and arranged on the back side. This excitation loop pattern 4 is connected to an excitation power source 7 via nodes n1 and n2.

  An A-phase detection loop pattern 5a is formed and arranged on the base 12a of the A-phase second plane 2a, and is connected to the nodes n3a and n4a that are detection ends. The A phase detection loop pattern 5a is composed of coil patterns Ca1, Ca2,... Can-1, Can, which have the same shape, as shown in the figure, and is arranged at a pitch p. Each coil pattern Ca1, Ca2,. -Can-1 and Can are connected in series so that the winding direction of one Ca1, Can is opposite to the winding direction of the other Ca1, Can-1 by a pattern indicated by dotted lines in Can 1, It is connected to the nodes n3a and n4a. The coil patterns Ca1, Ca2,... Can-1, and Can have a spiral shape in which the width direction is folded at s1 and s2, and the longitudinal direction is folded at p1 and p2.

  Similarly, a B-phase detection loop pattern 5b is formed and disposed on the base 12b of the B-phase second plane 2b, and is connected to the nodes n3b and n4b which are detection ends. The B phase detection loop pattern 5b is composed of coil patterns Cb1, Cb2,... Cbn-1, Cbn having the same shape as shown in the figure, and is the same as the shape of the A phase detection loop pattern 5a. The phase detection loop pattern 5a is formed and arranged with a 1 / 2p shift to the right.

  A resonance loop pattern 6 serving as a resonance coil is formed on the third plane 3. Similarly to the detection loop pattern 5, the resonance loop pattern 6 is formed in a spiral shape having a size P1 indicated by a solid line, folded in the width (vertical) direction with the width of s1 and s2, and folded in the longitudinal direction with p1 and p2. ing. Further, both ends of the resonance loop pattern 6 are connected to the resonance capacitor C. The third plane 3 opposes the first plane 1 and the second planes 2a and 2b for the A phase and B phase with a space therebetween, and in this example, the third plane 3 is arranged so as to be able to translate in the horizontal direction of the drawing.

  The first plane 1, the second planes 2a and 2b for the A phase and the B phase, and the third plane can be configured using a multilayer substrate, as in the first mode. Specifically, as shown in FIG. 5, the first substrate 11 constituting the first plane 1, the A phase second substrate 12 a constituting the A phase second plane 2 a, and the B phase As in the first embodiment, an insulating substrate 24 made of the same material as that of these substrates 11, 12 a, 12 b is provided between the B-phase second substrate 12 b constituting the second plane 2 b for use. A laminated substrate is used. Conductive layers 14 and 15 are vertically arranged on the respective substrates 11, 12 a, and 12 b, and the short circuit of the conductive layers 14 and 15 is prevented by the insulating substrate 24. It should be noted that the thickness of the laminated body or the like is expressed larger than the actual thickness for easy understanding of the drawing.

Next, the operation of the position detection apparatus of this illustrated example will be described.
First, it is assumed that the third plane 3 does not exist or exists outside the measurement region. Now, even if an excitation current flows from the excitation power source 7 to the excitation loop 4, the operation is the same as the operation principle of the first mode described in FIG. 1, so the A phase detection loop pattern 5a and the B phase detection loop pattern 5b. No detection voltage is generated at the detection end nodes 3a and 4a and the nodes 3b and 4b.

  Next, when the third plane 3 is arranged at a distance from the second plane 2a for A phase and the second plane 2b for B phase and the excitation power source 7 is activated, the first plane of FIG. The same operation as that of the aspect is performed. At the origin og position of the third plane 3 shown in FIG. 4, the loop area Cr of the resonance loop pattern 6 is different from the loop area Ca1 and the loop with respect to the A phase detection loop pattern 5a of the second plane 2 for A phase. Since it is magnetically coupled equally to the area Ca2, the electromotive force is canceled and no detection voltage appears at the nodes n3a and n4a.

  On the other hand, since the B phase detection loop pattern 5b is magnetically coupled only with the loop area Cb1, the same positive phase maximum detection voltage as the excitation power supply 7 is output as the B phase detection voltage to the nodes n3b and n4b. The

  Next, when the third plane moves in the right direction of the drawing in the width s1 direction and is translated while maintaining the same interval, the third plane operates in the same manner as the first aspect of FIG. A sinusoidal detection voltage having a period of 2p indicated by a dotted line in FIG. 6 is output as the A-phase detection voltage to the nodes n3a and n4a which are the A-phase detection ends. On the other hand, at the nodes n3b and n4b which are the B-phase detection ends, as shown by the solid line, a sine-wave detection voltage having a period of 2p having a phase difference of 1 / 2p with respect to the A-phase detection voltage is output as the B-phase detection voltage. Is done.

  If the A phase detection voltage is a sine wave detection voltage, the B phase detection voltage is a cosine wave detection voltage. By changing the shape of the coil pattern, the change in the magnetic coupling with respect to the moving position can be made closer to a sine wave, so that highly accurate detection of sine wave and cosine wave voltages can be realized. It can be seen that an inexpensive and high-precision printed board type cordless linear resolver can be practically used as the cordless linear position detecting device.

[Third Aspect]
Next, a third aspect of the present invention will be described. 7, 8 and 9 are plan views showing a third embodiment of the present invention. FIG. 7 is a plan view showing the first plane 1 and the second A-phase plane 2a, FIG. 8 is a plan view showing the second B-phase plane 2b and the third plane 3, and FIG. It is a schematic sectional drawing which shows the state with which these were combined. In this aspect, an example applied to a rotational position detection device is shown.

  That is, the first plane, the second plane, and the third plane have a shape corresponding to the rotating body, for example, a disk shape, and the excitation coil, the detection coil, and the resonance coil are rotationally symmetric with respect to the rotation center. Is formed. By adopting such a configuration, the third plane can rotate freely with respect to the first plane and the second plane, and corresponds to the rotational movement of the third plane which is the movable portion. The rotation position can be detected by detecting two signals of phase A and phase B having a phase difference of 90 ° in electrical angle. Other constituent elements are the same as those of the first embodiment shown in FIG. 1, and the same constituent elements are denoted by the same reference numerals and description thereof is omitted.

  As shown in the figure, the conductor excitation loop pattern 4 of the first plane 1 is formed on a base body 11 having a circular hole 10 for mounting a rotating shaft in the center of a disk, and is a combination of r1 to r6. A circular coil is made up of a coil loop that turns back and changes its winding direction. Also, the solid line loop in the figure is formed and arranged on the front surface side of the base material 11 and the dotted line loop is formed on the back surface side, and is connected to the excitation power source 7 via nodes n1 and n2.

  This multiple circle excitation loop pattern 4 is equivalent to the rectangular and spiral excitation loop pattern 4 of the first embodiment shown in FIG. Further, the following A and B phase detection loop patterns 5a and 5b and the resonance loop pattern 6 are also basically formed by arranging the rectangular loop pattern of the first aspect in a circular shape like the excitation loop. The operation is similar to the operation principle of FIG.

  Further, a pattern composed of two arcuate spiral coil patterns as shown in FIG. 11 is equivalent to the excitation loop pattern 4 of FIG. 7, and can be used in place of the excitation loop pattern 4 of FIG.

  A phase A detection loop pattern 5a is formed and disposed on a base 12a having a circular hole 10 for mounting a rotating shaft in the center on the second plane 2a for A phase, and a node serving as a detection end It is connected to n3a and n4a. The A-phase detection loop pattern 5a is composed of arc coil patterns C11a and C12a having the same shape and arranged rotationally symmetrically with a pitch 1p as shown in the figure. The coil patterns C11a and C12a are connected in series so that the winding direction of the coil pattern C12a is opposite to the winding direction of the coil pattern C11a by the pattern indicated by the dotted line, and connected to the nodes n3a and n4a serving as detection ends. ing. The coil patterns C11a and C12a have a spiral shape in which the radius of the arc is the same as the radii r1 to r6 of the multiple circle of the excitation loop pattern 4 and is folded at angles θ1 to θ3.

  On the other hand, a B-phase detection loop pattern 5b is formed and disposed on a base 12b having a circular hole 10 for mounting a rotating shaft in the center in the second plane 2b for B-phase shown in FIG. Are connected to the nodes n3b and n4b which are detection ends. As shown in the figure, the B-phase detection loop pattern 5b includes arc coil patterns C11b and C12b obtained by rotating the A-phase detection loop pattern 5a to the right by 1 / 2p (90 °).

  The third plane 3 shown in FIG. 8 is formed in a disc shape having an opening 10 so as to face the first plane 1 and the second plane 2 shown in FIGS. It is formed and arranged so that it can freely rotate clockwise or counterclockwise around the center of the plate.

  On the third plane 3, a resonance loop pattern 6 is formed and arranged on a base 13 having a disc shape and a circular hole 10 for mounting a rotation shaft in the center. The resonance loop pattern 6 is an arc coil pattern that corresponds to the semicircle of the A-phase or B-phase detection loop patterns 5a and 5b, that is, either the forward winding or the reverse winding (in this example, the forward winding). The resonance capacitor C is connected to both ends of the coil.

  The first plane 1 and the second planes 2a and 2b are normally fixed, and the positional relationship of the second planes 2a and 2b with respect to the first plane 1 is also fixed. The first plane 1 and the second planes 2a and 2b can be formed by separately preparing a base, but can also be integrated. When integrated, the first plane 1 and the second plane 2 may be stacked or stacked, but a short circuit between the excitation loop pattern 4 and the detection loop pattern 5 formed on these planes is prevented. Therefore, it is necessary to provide an insulating layer between them. This insulating layer may be air, but is preferably a laminate using the same material as the base constituting the first plane 1 and the second plane 2.

  Specifically, as shown in FIG. 9, between the first substrate 11 constituting the first plane 1 and the second substrates 12a and 12b constituting the second planes 2a and 2b, these An insulating substrate 24 made of the same material as the substrates 11, 12 a, and 12 b is provided to form a laminated substrate. Here, a conductor layer 14 that forms the excitation loop pattern 4 is arranged on the first substrate 11 and a conductor layer 15 that forms the detection loop pattern 5 is arranged on the second substrate 12a and 12b. Has been. The insulating substrate 24 prevents the conductor layers 14 and 15 from being short-circuited. It should be noted that the thickness of the laminated body 9 or the like is expressed larger than the actual thickness for easy understanding of the drawing. Lamination of the substrate can be easily performed by a known method such as thermocompression bonding.

  Next, the operation of this rotational position detection device will be described. Now, if there is no third plane 3 and only the first plane 1 and the second planes 2a and 2b, the A-phase detection loop 5a and the B-phase detection loop 5b Since the operation is the same as the basic operation principle described in the first mode shown in FIG. 1, no detection voltage is generated at the detection terminals n3a and n4a and the detection terminals n3b and n4b.

  Here, as shown in FIGS. 7, 8, and 9, the third plane 3 is disposed at a distance from the first plane 1 and the second planes 2 a and 2 b, and the excitation power supply 7 is activated. At the origin position og in the illustrated example, the loop area of the resonance loop 6 is magnetically coupled only to the loop area of the excitation loop 4 and the loop area C11a of the A-phase detection loop 5a. For this reason, a detection current flows through the A phase detection loop 5a, and the maximum positive detection voltage of the same positive phase as that of the excitation power supply 7 is output to the detection terminals n3a and n4a as the A phase detection voltage as shown by the solid line in FIG.

  On the other hand, since the resonance loop pattern 6 is equally magnetically coupled to the loop area C11b and the loop area C12b of the B phase detection loop pattern, the electromotive forces cancel each other, and the detection end nodes n3b and n4b of the B phase detection loop pattern 5b The detection voltage becomes zero.

  Next, when the third plane 3 rotates around the center in the clockwise direction while maintaining the same distance, the third plane 3 operates based on the basic operation principle similar to the first mode shown in FIG. Therefore, according to the rotation, a sinusoidal detection voltage with a period 2P indicated by a solid line in FIG. 10 is output as the A-phase detection voltage to the detection ends n3a and n4a of the A-phase detection loop pattern 5a.

  On the other hand, as shown by the dotted lines at the detection ends n3b and n4b of the B phase detection loop pattern 5b, a sine wave detection voltage having a period of 2p having a phase difference of 1 / 2p with respect to the A phase detection voltage is detected as the B phase. Output as voltage. If the A phase detection voltage is a sine wave detection voltage, the B phase detection voltage is a cosine wave detection voltage. By changing the shape of the coil pattern (the angle of θ1 to θ3, etc.), the change in magnetic coupling with respect to the rotational position can be made closer to a sine wave, so that highly accurate detection of sine wave and cosine wave voltages can be realized. In addition, according to the second embodiment, it can be understood that an inexpensive and highly accurate printed board type cordless resolver can be practically used as the cordless rotational position detecting device.

  This embodiment shows an example of a 1-pole resolver that outputs a detection voltage of a sine wave and a cosine wave of one cycle with respect to a rotation of a mechanical angle of 360 °. An n-pole resolver can be realized by forming and arranging n pairs of coils in each of the B-phase detection loops. Further, an n-pole resolver capable of detecting one rotation signal can be realized by additionally arranging a C-phase detection loop comprising a pair of coils in the n-pole resolver.

  The position detection device of the present invention can be suitably applied to a linear position detection device such as a linear encoder, and a rotation position detection device such as a rotary encoder or resolver.

It is a top view which shows the 1st aspect of the position detection apparatus of this invention. It is a schematic sectional drawing which shows the 1st aspect of the position detection apparatus of this invention. It is a wave form diagram which shows the detection voltage of the 1st aspect of the position detection apparatus of this invention. It is a top view which shows the 2nd aspect of the position detection apparatus of this invention. It is a schematic sectional drawing which shows the 2nd aspect of the position detection apparatus of this invention. It is a wave form diagram which shows the detection voltage of the 2nd aspect of the position detection apparatus of this invention. It is a top view which shows the 3rd aspect of the position detection apparatus of this invention. It is a top view which shows the 3rd aspect of the position detection apparatus of this invention. It is a schematic sectional drawing which shows the 2nd aspect of the position detection apparatus of this invention. It is a wave form diagram which shows the detection voltage of the 3rd aspect of the position detection apparatus of this invention. It is a top view which shows the structure of the other excitation loop pattern in the 3rd aspect of the position detection apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st plane 2 2nd plane 3 3rd plane 4 Excitation loop pattern 5 Detection loop pattern 6 Resonance loop pattern

Claims (6)

An exciting coil formed on the first plane by being wound at least in a spiral shape for 2 t or more;
A detection coil having one or more pairs of coil units formed on the second plane so that forward winding and reverse winding alternately appear in one pitch unit in the same direction as at least the excitation coil;
A resonance coil having at least a resonance capacitor connected in parallel on the third plane;
At least the excitation coil in the first plane and the detection coil in the second plane have magnetic coupling;
The third plane is spaced apart from the first plane and the second plane via a space, and is freely movable in a specific direction in a detection coil forming region serving as a detection region. And / or the detection coil and the resonance coil can be magnetically coupled,
A position detection device that obtains a position detection voltage from the detection coil according to the position of the resonance coil.   2. The position detecting device according to claim 1, wherein the exciting coil on the first plane and the detecting coil on the second plane are formed so as to extend in one direction, and the third plane moves so as to slide in this forming region. .   The position detecting device according to claim 1, wherein the excitation coil on the first plane and the detection coil on the second plane are formed rotationally symmetrically, and the third plane moves so as to rotate in this formation region.   The position detection device according to claim 1, wherein the excitation coil and the detection coil are formed by connecting discontinuous spiral coils in series.   The position detection device according to claim 1, wherein a resonance capacitor portion of the resonance coil is short-circuited.   The position detection device according to claim 1, wherein the first plane and the second plane are configured by a laminated substrate.

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