JP-7856763-B2 - Inductive position detector

JP7856763B2JP 7856763 B2JP7856763 B2JP 7856763B2JP-7856763-B2

Inventors

成澤浩太
寳田明彦

Assignees

オリエンタルモーター株式会社

Dates

Publication Date: 20260511
Application Date: 20230612
Priority Date: 20220614

Claims (15)

A stator having a wiring board, A rotor having non-conductive components positioned opposite the stator, and rotating relative to the stator about a predetermined axis of rotation, Multiple conductive targets of the same shape and size are periodically arranged along the circumference around the rotation axis and held by the non-conductive component of the rotor, and move along a rotational trajectory around the rotation axis as the rotor rotates, It includes a plurality of chip inductors, each constituting a plurality of detection coils, which are surface-mounted on the main surface of the wiring board of the stator, arranged to face the rotational trajectory with different spatial phases relative to the plurality of conductor targets, and which detect changes in the magnetic field accompanying the passage of the conductor targets . The conductor targets are arranged along the rotational trajectory at a predetermined conductor target period, An inductive position detector comprising a plurality of chip inductors arranged with a phase difference of one-quarter of a period with respect to the conductor target period, including at least one first-phase chip inductor, at least one second-phase chip inductor, at least one third-phase chip inductor, and at least one fourth-phase chip inductor.
The conductor targets are arranged along the rotational trajectory at a predetermined conductor target period, The inductive position detector according to claim 1, wherein the chip inductor has a coil width of 25% to 75% of the period of the conductor target along the rotational trajectory.
The 4N chip inductors (where N is a natural number) are arranged at equal intervals along the entire circumference of the rotational trajectory. The inductive position detector according to claim 1, wherein the number of conductive targets Y (where Y is a natural number) is represented by Y = 4NM ± N (where M is a natural number).
A stator having a wiring board, A rotor having non-conductive components positioned opposite the stator, and rotating relative to the stator about a predetermined axis of rotation, Multiple conductive targets of the same shape and size are periodically arranged along the circumference around the rotation axis and held by the non-conductive component of the rotor, and move along a rotational trajectory around the rotation axis as the rotor rotates, It includes a plurality of chip inductors, each constituting a plurality of detection coils, which are surface-mounted on the main surface of the wiring board of the stator, arranged to face the rotational trajectory with different spatial phases relative to the plurality of conductor targets, and which detect changes in the magnetic field accompanying the passage of the conductor targets. The 4N chip inductors (where N is a natural number) are arranged at equal intervals along the entire circumference of the rotational trajectory. An inductive position detector in which the number of conductive targets Y (where Y is a natural number) is expressed as Y = 4NM ± N (where M is a natural number).
A first set of the plurality of conductor targets and the plurality of chip inductors, whose rotational orbit is a first rotational orbit, and a second set of the plurality of conductor targets and the plurality of chip inductors, whose rotational orbit is a second rotational orbit different from the first rotational orbit, are provided sharing the stator and the rotor. The inductive position detector according to claim 1, wherein the number Y1 (where Y1 is a natural number) of the first set of plurality of conductive targets and the number Y2 ( where Y2 is a natural number) of the second set of plurality of conductive targets are different from each other.
A stator having a wiring board, A rotor having non-conductive components positioned opposite the stator, and rotating relative to the stator about a predetermined axis of rotation, Multiple conductive targets of the same shape and size are periodically arranged along the circumference around the rotation axis and held by the non-conductive component of the rotor, and move along a rotational trajectory around the rotation axis as the rotor rotates, It includes a plurality of chip inductors, each constituting a plurality of detection coils, which are surface-mounted on the main surface of the wiring board of the stator, arranged to face the rotational trajectory with different spatial phases relative to the plurality of conductor targets, and which detect changes in the magnetic field accompanying the passage of the conductor targets. A first set of the plurality of conductor targets and the plurality of chip inductors, whose rotational orbit is a first rotational orbit, and a second set of the plurality of conductor targets and the plurality of chip inductors, whose rotational orbit is a second rotational orbit different from the first rotational orbit, are provided sharing the stator and the rotor. The number Y of the first set of multiple conductor targets 1 (Y 1 Y is a natural number and the number of the second set of the plurality of conductor targets. 2 (Y 2 An inductive position detector in which (a is a natural number) and are different from each other.
The inductive position detector according to claim 5 or 6 , wherein the number Y1 of the first set of plurality of conductive targets and the number Y2 of the second set of plurality of conductive targets are relatively prime.
The inductive position detector according to claim 5 or 6, further comprising an excitation coil provided on the wiring board of the stator and shared for inducing voltage in the first set of the plurality of chip inductors and the second set of the plurality of chip inductors.
The inductive position detector according to claim 8, wherein the excitation coil includes an annular first excitation coil that encloses the first set of the plurality of chip inductors and the second set of the plurality of chip inductors when viewed along the axis of rotation, and an annular second excitation coil arranged around the axis of rotation so as to be enclosed by the first set of the plurality of chip inductors and the second set of the plurality of chip inductors when viewed along the axis of rotation.
An inductive position detector according to any one of claims 1 to 6, wherein each conductive target includes a conductive solid pattern or an annular coil conductive pattern formed on the non-conductive component, and the plurality of conductive targets are insulated from one another.
The induction type position detector according to any one of claims 1 to 6 , wherein the plurality of conductive targets are connected to each other to form an annular coil conductor pattern extending around the entire circumference.
The inductive position detector according to any one of claims 1 to 6 , wherein the chip inductor is a multilayer chip inductor having a pair of connecting electrodes at both ends.
An inductive position detector according to any one of claims 1 to 6, further comprising an excitation coil provided on the wiring board of the stator, formed in an annular shape that encloses the plurality of chip inductors when viewed along the axis of rotation, and generating a magnetic field for inducing voltage in the plurality of chip inductors.
The inductive position detector according to any one of claims 1 to 6 , wherein the plurality of chip inductors are connected to form an AC bridge circuit having a pair of AC voltage application terminals and a pair of signal detection terminals.
A stator having a wiring board, A rotor having non-conductive components positioned opposite the stator, and rotating relative to the stator about a predetermined axis of rotation, Multiple conductive targets of the same shape and size are periodically arranged along the circumference around the rotation axis and held by the non-conductive component of the rotor, and move along a rotational trajectory around the rotation axis as the rotor rotates, It includes a plurality of chip inductors, each constituting a plurality of detection coils, which are surface-mounted on the main surface of the wiring board of the stator, arranged to face the rotational trajectory with different spatial phases relative to the plurality of conductor targets, and which detect changes in the magnetic field accompanying the passage of the conductor targets. An inductive position detector in which the plurality of chip inductors are connected to form an AC bridge circuit having a pair of AC voltage application terminals and a pair of signal detection terminals.

Description

Related applications This application claims priority under Japanese Patent Application No. 2022-95845, filed on 14 June 2022, and the entire contents of that application are incorporated herein by reference. This invention relates to an inductive position detector. Various detection methods are used for position detectors that detect rotational position, including optical, magnetic, capacitive, resolver, and inductive types. Inductive position detectors move a movable part holding a conductor in an alternating magnetic field and detect changes in the magnetic field caused by the current induced in the conductor. Inductive position detectors are less susceptible to dust, dirt, and external magnetic fields, making them highly environmentally resistant. In addition, they have a simple structure, can be miniaturized and thinned, and are relatively inexpensive. Inductive position detectors are disclosed, for example, in Patent Documents 1 to 4. Patent documents 1 and 4 disclose a configuration in which an excitation coil and a detection coil are formed in a conductor pattern on a printed circuit board, and a conductor target is moved relative to the detection coil. The voltage induced in the detection coil by the alternating magnetic field generated by the excitation coil changes according to the positional relationship between the detection coil and the conductor target. This makes it possible to detect the position of the conductor target. Patent Document 2 discloses a configuration in which a detection coil is formed using a conductor pattern on a printed circuit board, an AC voltage is applied to the detection coil, and the change in the inductance of the detection coil is detected when a conductor target moves relative to the detection coil. Patent Document 3 discloses a configuration in which an excitation coil and a detection coil are formed using a conductive pattern on a silicon substrate. The detection principle is the same as that of Patent Documents 1 and 4. Japanese Unexamined Patent Publication No. 159101/1986Patent No. 5226694Patent No. 5300164Japanese Patent Publication No. 2021-56176Japanese Patent Publication No. 2000-49014 Figure 1 is an exploded perspective view illustrating the configuration of an inductive position detector according to the first embodiment of this invention.Figure 2 is a side view of the inductive position detector shown in Figure 1.Figure 3 is a plan view showing the relative arrangement of the rotor's conductor target and the chip inductor placed on the stator.Figure 4 is an electrical circuit diagram showing the equivalent circuit of the stator.Figures 5A, 5B, and 5C are waveform diagrams showing examples of AC voltages generated by an excitation source and detection signals with a 90-degree phase difference.Figure 6 is an exploded perspective view of an inductive position detector according to a second embodiment of the present invention.Figure 7 is a plan view showing the relative arrangement of the rotor's conductor target and the chip inductor placed on the stator.Figure 8 is an electrical circuit diagram showing the equivalent circuit of the stator.Figure 9 is an exploded perspective view showing the configuration of an inductive position detector according to a third embodiment of the present invention.Figure 10 is an electrical circuit diagram showing the equivalent circuit of the stator of the inductive position detector shown in Figure 9.Figure 11 is an exploded perspective view illustrating the configuration of an inductive position detector according to a fourth embodiment of the present invention.Figure 12 is a plan view showing the positional relationship between the rotor's conductor target and the chip inductor placed on the stator.Figure 13 is an electrical circuit diagram showing the equivalent circuit of the stator.Figure 14A is a plan view showing an example configuration comprising a conductor target formed from a coil-shaped conductor pattern.Figure 14B is a plan view showing another configuration example that includes a conductor target formed with a coil-shaped conductor pattern.Figures 15A to 15E show examples of various conductive targets.Figures 16A to 16D show examples of conductor target divisions in a continuous annular coil conductor pattern around its entire circumference. The embodiments of this invention will be described in detail below with reference to the accompanying drawings. Figure 1 is an exploded perspective view illustrating the configuration of an inductive position detector 100 according to the first embodiment of this invention. Figure 2 is a side view of the inductive position detector 100 as seen in the direction of arrow 101 in Figure 1. The inductive position detector 100 includes a stator 1 and a rotor 2 that rotates relative to the stator 1 around a rotation axis 3a, and is configured to output a detection signal representing the relative rotational position of the rotor 2 with respect to the stator 1 around the rotat