JP2016125834A - Induction detection type rotary encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction detection type rotary encoder with which it is possible to downsize and conduct a stroke-suppressed and high-accuracy position detection.SOLUTION: An induction detection type rotary encoder comprises a first transmission winding and a second transmission winding provided in a stator, a first reception winding provided in a first area, a second reception winding provided in a second area, a first magnetic flux coupling element provided in a third area of a rotor, and a second magnetic flux coupling element provided in a fourth area. The second area, the first area, the third area, and the fourth area are arranged in an axial direction in the order stated. A shortest distance between the first transmission winding and the first magnetic flux coupling element is shorter than a shortest distance between the second transmission winding and the first magnetic flux coupling element. A shortest distance between the second transmission winding and the second magnetic flux coupling element is shorter than a shortest distance between the first transmission winding and the second magnetic flux coupling element. The shortest distance between the first transmission winding and the first magnetic flux coupling element is shorter than a shortest distance between the first transmission winding and the second magnetic flux coupling element. The shortest distance between the second transmission winding and the second magnetic flux coupling element is shorter than the shortest distance between the second transmission winding and the first magnetic flux coupling element.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an inductive detection type rotary encoder that measures a rotation angle by using magnetic flux coupling generated between wirings provided on a rotor and a stator.

  The inductive detection type rotary encoder includes a stator provided with a transmission winding and a reception winding, and a rotor provided with a magnetic flux coupling body. In this inductive detection type rotary encoder, a transmission current whose current direction changes periodically flows through the transmission winding. The magnetic flux coupling body generates an induced current based on a magnetic field generated by a transmission current that flows through the transmission winding. The receiving winding detects an induced voltage based on a magnetic field generated by an induced current flowing through the magnetic flux coupling body.

  For example, in the inductive detection type rotary encoder disclosed in Patent Document 1, a plurality of transmission windings and a plurality of reception windings are laminated on a stator via an insulating layer. In addition, a plurality of magnetic flux coupling bodies are stacked on the rotor via an insulating layer.

  The absolute encoder described in Patent Document 1 includes two tracks each including a transmission winding, a reception winding, and a magnetic flux coupling body, and has a configuration in which these tracks are arranged concentrically.

  In addition, in the inductive detection type rotary encoder described in Patent Document 2, the induction detection type rotary encoder can be reduced in size by forming a plurality of transmission windings, a plurality of reception windings, and a plurality of magnetic flux coupling bodies in a laminated structure. doing.

JP 2006-322927 A JP 2013-152163 A

  However, the absolute encoder described in Patent Document 1 has a problem in that the outer diameter of the encoder increases because the two tracks are arranged concentrically. In this regard, the inductive detection type rotary encoder described in Patent Document 2 has a merit that the size of the encoder can be reduced because two tracks having the same outer diameter are stacked. However, there is a problem that crosstalk (noise component) from a track different from the track to be measured is likely to occur, resulting in a decrease in measurement accuracy.

  An object of the present invention is to provide an inductive detection type rotary encoder that can perform position detection with high accuracy while miniaturizing an encoder and suppressing crosstalk.

  In order to solve the above-described problems, an inductive detection type rotary encoder according to the present invention includes a stator, a rotor facing the stator and rotatably provided around a rotation axis, a stator provided, and the rotation axis as a center. The first transmission winding having the first radius, the second transmission winding provided on the stator and having the second radius around the rotation axis, and the annular first transmission winding provided on the stator and centering on the rotation axis. A first receiving winding formed in one region and having a first inner radius and a first outer radius centered on the rotation axis, and provided in the stator and formed in an annular second region centered on the rotation axis. A second receiving winding formed between the first receiving winding and the first receiving layer and having a second inner radius and a second outer radius around the rotation axis; and the rotor, An annular region centered on the rotation axis and along the rotation axis A first magnetic flux coupling body having a third inner radius and a third outer radius with the rotation axis as a center, and a rotor provided at a third region that overlaps the first region in the direction, with the rotation axis as a center. A fourth inner radius that is formed in a fourth region that is an annular region and overlaps the second region in the axial direction, and is formed through a second insulating layer between the first magnetic flux coupling body and centering on the rotation axis And a second magnetic flux coupling body having a fourth outer radius, and the second region, the first region, the third region, and the fourth region are arranged in this order in the axial direction, The shortest distance from the first magnetic flux coupling body is shorter than the shortest distance between the second transmission winding and the first magnetic flux coupling body, and the shortest distance between the second transmission winding and the second magnetic flux coupling body is the first transmission winding. The shortest distance between the first transmission winding and the first magnetic flux coupling body is shorter than the shortest distance between the line and the second magnetic flux coupling body. The shortest distance between the second transmission winding and the first magnetic flux coupling body is shorter than the shortest distance between the second transmission winding and the first magnetic flux coupling body. To do.

  According to such a configuration, the outer diameter of the encoder can be reduced by the laminated structure of the first receiving winding, the second receiving winding, the first magnetic flux coupling body, and the second magnetic flux coupling body. In addition, the shortest distance between the first transmission winding and the first magnetic flux coupling body is shorter than the shortest distance between the second transmission winding and the first magnetic flux coupling body. The influence of crosstalk from the winding is suppressed. In addition, by making the shortest distance between the second transmission winding and the second magnetic flux coupling body shorter than the shortest distance between the first transmission winding and the second magnetic flux coupling body, the second magnetic flux coupling body performs the first transmission. The influence of crosstalk from the winding is suppressed.

  In the inductive detection type rotary encoder of the present invention, the first inner radius is larger than the second inner radius, the second outer radius is greater than or equal to the first inner radius, and the first outer radius is larger than the second outer radius. It can be large. According to such a configuration, a space for arranging the second transmission winding is ensured between the second reception winding and the second magnetic flux coupling body in the axial direction while suppressing an increase in the outer diameter of the encoder. can do.

  In the inductive detection type rotary encoder of the present invention, the third inner radius is larger than the fourth inner radius, the fourth outer radius is greater than or equal to the third inner radius, and the third outer radius is larger than the fourth outer radius. May be larger. According to such a configuration, a space for arranging the second transmission winding is ensured between the second reception winding and the second magnetic flux coupling body in the axial direction while suppressing an increase in the outer diameter of the encoder. can do.

  In the inductive detection type rotary encoder of the present invention, the first radius may be larger than the first outer radius, and the second radius may be smaller than the first inner radius. According to such a configuration, it is possible to realize an arrangement that suppresses the influence of crosstalk while suppressing an increase in the outer diameter of the encoder.

  In the inductive detection type rotary encoder of the present invention, the first transmission winding may be provided in the same layer as the second transmission winding. According to such a configuration, the encoder can be thinned.

  In the inductive detection type rotary encoder of the present invention, the first magnetic flux coupling body and the first reception winding are provided in a shape that periodically changes at a first pitch in the rotation direction around the rotation axis, and the second magnetic flux coupling The body and the second receiving winding may be provided in a shape that periodically changes at a second pitch different from the first pitch in the rotation direction about the rotation axis. According to such a configuration, an absolute value in the rotation angle of the rotor can be obtained.

  In the inductive detection type rotary encoder of the present invention, the first magnetic flux coupling body includes a first annular current path provided in an annular shape with the same radius as the third inner radius around the rotation axis, and the second magnetic flux coupling body is A second annular current path provided in an annular shape with the same radius as the fourth outer radius about the rotation axis may be included. According to such a configuration, the first annular current path serves as a shield, and the influence of crosstalk from the second transmission winding to the first magnetic flux coupling body can be suppressed. In addition, the second annular current path serves as a shield, and the influence of crosstalk from the first transmission winding to the second magnetic flux coupling body can be suppressed.

  In the inductive detection type rotary encoder of the present invention, a first annular current path provided in an annular shape around the rotational axis inside the first magnetic flux coupling body, and an annular shape around the rotational axis outside the second magnetic flux coupling body. And a second annular current path provided. According to such a configuration, the first annular current path serves as a shield, and the influence of crosstalk from the second transmission winding to the first magnetic flux coupling body can be suppressed. In addition, the second annular current path serves as a shield, and the influence of crosstalk from the first transmission winding to the second magnetic flux coupling body can be suppressed.

It is a front view which illustrates a digital micrometer. It is sectional drawing which illustrates the structure of the induction | guidance | derivation detection type rotary encoder which concerns on 1st Embodiment. It is a typical sectional view which illustrates the composition of a stator and a rotor. It is a top view which illustrates the 1st transmission winding, the 2nd transmission winding, and the 1st reception winding. It is a top view which illustrates one receiving winding part of the 1st receiving winding. It is a top view which illustrates the 2nd receiving winding. It is a top view which illustrates one receiving winding part of the 2nd receiving winding. It is a top view which illustrates the 1st magnetic flux coupling body. It is a top view which illustrates the 2nd magnetic flux coupling body. It is sectional drawing which illustrates the induction | guidance | derivation detection type rotary encoder which concerns on 2nd Embodiment. It is a top view which illustrates the magnetic flux coupling body which concerns on 2nd Embodiment. It is a top view which illustrates the magnetic flux coupling body which concerns on 2nd Embodiment. It is sectional drawing which illustrates the induction | guidance | derivation detection type rotary encoder which concerns on 3rd Embodiment. It is a top view which illustrates the magnetic flux coupling body which concerns on 3rd Embodiment. It is a top view which illustrates the magnetic flux coupling body which concerns on 3rd Embodiment.

[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. In the following description, the same members are denoted by the same reference numerals, and the description of the members once described is omitted as appropriate.
FIG. 1 is a front view illustrating a digital micrometer to which the inductive detection type rotary encoder according to the first embodiment is applied. As shown in FIG. 1, the digital micrometer 1 includes a frame 3, a thimble 5, a spindle 7, and a display unit 9. The frame 3 includes a main body portion 3a that supports the thimble 5 and the spindle 7, and an anvil portion 3b that is provided at a distance from the main body portion 3a. The thimble 5 is rotatably attached to the main body 3 a of the frame 3. The spindle 7 that is a measuring element is rotatably supported by the main body 3 a of the frame 3.

  One end 7 a side of the spindle 7 protrudes from the main body portion 3 a of the frame 3 toward the anvil portion 3 b. An anvil 3c is attached to the anvil portion 3b so as to face one end 7a of the spindle 7. The other end side of the spindle 7 enters the main body 3 a of the frame 3. A feed screw (not shown in FIG. 1) is provided on the other end side of the spindle 7. This feed screw is fitted into a nut (not shown in FIG. 1) provided in the thimble 5.

  A display unit 9 is provided on the exterior surface of the main body 3 a of the frame 3. The display unit 9 is a liquid crystal display panel that displays a numerical value or the like by a segment method, for example. In such a configuration, when the thimble 5 is rotated in the forward direction, the spindle 7 moves to the anvil 3c side along the axis of the spindle 7 (rotation axis AX). Thereby, the space | interval of the spindle 7 and the anvil 3c becomes narrow. On the other hand, when the thimble 5 is rotated in the reverse direction, the spindle 7 moves along the rotation axis AX to the opposite side to the anvil 3c. Thereby, the space | interval of the spindle 7 and the anvil 3c becomes wide.

  When measuring the size of the object, the object is placed between the anvil 3c and one end 7a of the spindle 7, and the thimble 5 is rotated in the forward direction so that the anvil 3c and one end 7a of the spindle 7 are To sandwich the object. The distance between the anvil 3c and the one end 7a of the spindle 7 at this time is displayed on the display unit 9 as a measurement result.

Next, the configuration of the inductive detection type rotary encoder according to the present embodiment will be described.
FIG. 2 is a cross-sectional view illustrating the configuration of the inductive detection type rotary encoder according to this embodiment.
As shown in FIG. 2, the inductive detection type rotary encoder 11 is provided in the main body 3 a of the frame 3.

  The induction detection type rotary encoder 11 includes a stator 14 and a rotor 15. The stator 14 is fixed to the main body 3 a of the frame 3 via the stator bush 21. The rotor 15 faces the stator 14 and is provided to be rotatable about the rotation axis AX. The rotor 15 is fixed to the end face of the cylindrical rotor bush 19. The spindle 7 is inserted into the rotor bush 19 and the stator bush 21.

  On the surface of the spindle 7, a feed screw 23 that is fitted into a nut disposed inside the thimble 5 is formed. Further, a key groove 25 is provided on the surface of the spindle 7 in the longitudinal direction of the spindle 7 (advancing and retracting direction of the spindle 7). The key groove 25 is fitted with a tip portion of a pin 27 fixed to the rotor bush 19. As a result, when the spindle 7 rotates, the rotational force is transmitted to the rotor bush 19 via the pin 27 and the rotor 15 rotates. That is, the rotor 15 rotates in conjunction with the rotation of the spindle 7. Since the pin 27 is not fixed to the key groove 25, the rotor 15 can be rotated without moving the rotor 15 together with the spindle 7. On the other hand, the stator bush 21 does not rotate even if the spindle 7 is rotated. That is, the stator 14 remains fixed even when the spindle 7 is rotated.

Next, the configuration of the stator 14 and the rotor 15 will be described.
FIG. 3 is a schematic cross-sectional view illustrating the configuration of the stator and the rotor.
As illustrated in FIG. 3, the stator 14 includes stacked insulating layers 33A, 33B, 33C, and 33D. The insulating layers 33A, 33B, 33C, and 33D are stacked in this order in the direction away from the rotor 15. The insulating layers 33A, 33B, 33C and 33D are provided with a through hole 34 through which the spindle 7 passes.

  The rotor 15 has laminated insulating layers 42A and 42B. The insulating layers 42 </ b> A and 42 </ b> B are stacked in this order in a direction away from the stator 14. The insulating layers 42A and 42B are provided with a through hole 43 through which the spindle 7 passes.

  The stator 14 is provided with a first reception winding 32a and a second reception winding 32b. The first reception winding 32a is formed in an annular first region R1 centered on the rotation axis AX. A part of the first reception winding 32a is formed on the rotor 15 side of the insulating layer 33A, and the other part is formed between the insulating layer 33A and the insulating layer 33B. These are connected through a through hole or a via penetrating the insulating layer 33A.

  The second reception winding 32b is formed in an annular second region R2 centered on the rotation axis AX. A part of the second reception winding 32b is formed between the insulating layer 33B and the insulating layer 33C, and the other part is formed between the insulating layer 33C and the insulating layer 33D. These are connected through a through hole or a via penetrating the insulating layer 33C.

  Further, the stator 14 is provided with an annular first transmission winding 31a and second transmission winding 31b centered on the rotation axis AX. The first transmission winding 31 a is provided on the outer peripheral side of the stator 14, and the second transmission winding 31 b is provided on the inner peripheral side of the stator 14. The direction of the current flowing through the first transmission winding 31a changes periodically. A magnetic field generated by this current is applied to the first magnetic flux coupling body 41 a formed on the rotor 15. Further, the direction of the current flowing through the second transmission winding 31b changes periodically. A magnetic field generated by this current is applied to the second magnetic flux coupling body 41 b formed in the rotor 15.

  The rotor 15 is provided with a first magnetic flux coupling body 41a and a second magnetic flux coupling body 41b. The first magnetic flux coupling body 41a is formed in an annular third region R3 centered on the rotation axis AX. The first magnetic flux coupling body 41a is provided on the stator 14 side of the insulating layer 42A. The second magnetic flux coupling body 41b is formed in an annular fourth region R4 centered on the rotation axis AX. The second magnetic flux coupling body 41b is formed between the insulating layer 42A and the insulating layer 42B.

  In the present embodiment, the second region R2, the first region R1, the third region R3, and the fourth region R4 are arranged in this order. As a result, the first receiving winding 32a faces the first magnetic flux coupling body 41a, and the second receiving winding 32b faces the second magnetic flux coupling body 41b.

Here, the operation of the inductive detection type rotary encoder 11 will be described.
In the inductive detection type rotary encoder 11, the direction of the transmission current flowing through the first transmission winding 31a is periodically changed, and a magnetic field generated by this transmission current is applied to the first magnetic flux coupling body 41a formed on the rotor 15. . An induced current due to magnetic flux coupling flows through the first magnetic flux coupling body 41a. The first receiving winding 32a detects an induced voltage based on a magnetic field generated by an induced current flowing through the first magnetic flux coupling body 41a.

  Further, in the inductive detection type rotary encoder 11, the direction of the transmission current flowing through the second transmission winding 31b is periodically changed, and the magnetic field generated by the transmission current is changed to the second magnetic flux coupling body 41b formed in the rotor 15. To give. An induced current caused by magnetic flux coupling flows through the second magnetic flux coupling body 41b. The second receiving winding 32b detects an induced voltage based on a magnetic field generated by the induced current flowing through the second magnetic flux coupling body 41b.

  In the inductive detection type rotary encoder 11 according to this embodiment, the shortest distance between the first transmission winding 31a and the first magnetic flux coupling body 41a is smaller than the shortest distance between the second transmission winding 31b and the first magnetic flux coupling body 41a. Is also shorter. Furthermore, the shortest distance between the second transmission winding 31b and the second magnetic flux coupling body 41b is shorter than the shortest distance between the first transmission winding 31a and the second magnetic flux coupling body 41b. Furthermore, the shortest distance between the first transmission winding 31a and the first magnetic flux coupling body 41a is shorter than the shortest distance between the first transmission winding 31a and the second magnetic flux coupling body 41b. Further, the shortest distance between the second transmission winding 31b and the second magnetic flux coupling body 41b is shorter than the shortest distance between the second transmission winding 31b and the first magnetic flux coupling body 41a.

In such a configuration, a magnetic field is generated by a current flowing through the first transmission winding 31a, and an induced current flows through the first magnetic flux coupling body 41a by this magnetic field. At this time, the second magnetic flux coupling body 41b is affected by the magnetic field generated by the first transmission winding 31a and the first magnetic flux coupling body 41a. In the present embodiment, since the second magnetic flux coupling body 41b is located away from the first transmission winding 31a and the first magnetic flux coupling body 41a, the magnetic field of the first transmission winding 31a and the first magnetic flux coupling body 41a is reduced. The second magnetic flux coupling body 41b is not easily affected.
Similarly, when a current flows through the second transmission winding 31b, a magnetic field is generated, and an induced current flows through the second magnetic flux coupling body 41b due to this magnetic field. At this time, the first magnetic flux coupling body 41a is affected by the magnetic field generated by the second transmission winding 31b and the second magnetic flux coupling body 41b. In the present embodiment, since the first magnetic flux coupling body 41a is located away from the second transmission winding 31b and the second magnetic flux coupling body 41b, the magnetic field of the second transmission winding 31b and the second magnetic flux coupling body 41b is reduced. The first magnetic flux coupling body 41a is not easily affected.
As a result, in the first magnetic flux coupling body 41a, the influence of crosstalk from the second transmission winding 31b is suppressed. Further, in the second magnetic flux coupling body 41b, the influence of crosstalk from the first transmission winding 31a is suppressed.

  In order to realize the above distance relationship, in the present embodiment, the diameters of the first reception winding 32a and the first magnetic flux coupling body 41a are made different from the diameters of the second reception winding 32b and the second magnetic flux coupling body 41b. Thus, the first transmission winding 31a and the first magnetic flux coupling body 41a are brought close to each other, and the second transmission winding 31b is placed close to the second magnetic flux coupling body 41b.

Here, a specific example for realizing the above positional relationship will be described.
First, an inner radius around the rotation axis AX of the first reception winding 32a is a first inner radius r11, and an outer radius is a first outer radius r12. An inner radius around the rotation axis AX of the second reception winding 32b is a second inner radius r21, and an outer radius is a second outer radius r22. The inner radius around the rotation axis AX of the first magnetic flux coupling body 41a is the third inner radius r31, and the outer radius is the third outer radius r32. The inner radius around the rotation axis AX of the second magnetic flux coupling body 41b is the fourth inner radius r41, and the outer radius is the fourth outer radius r42. Further, a radius around the rotation axis AX of the first transmission winding 31a is a first radius r10, and a radius around the rotation axis AX of the second transmission winding 31b is a second radius r20.

  Here, the inner radius is a radius on the inner side of the ring when the region where the winding and the magnetic flux coupling body are provided as a ring-shaped region having a certain width as viewed in the direction along the rotation axis AX. Say. Further, the outer radius means a radius outside the ring of this ring-shaped region. The first radius means a radius at the center position of the winding when the first transmission winding 31a is circular. The second radius is a radius at the center position of the winding when the second transmission winding 31b is circular.

  In the inductive detection type rotary encoder 11 according to the present embodiment, the first inner radius r11 is larger than the second inner radius r21, the second outer radius r22 is greater than or equal to the first inner radius r11, and the first outer radius r12. Is larger than the second outer radius r22. Thereby, the outer diameter of the encoder can be reduced as compared with the case where the first reception winding 32a and the second reception winding 32b are arranged in the same layer.

  In the inductive detection type rotary encoder 11 according to the present embodiment, the third inner radius r31 is larger than the fourth inner radius r41, the fourth outer radius r42 is equal to or greater than the third inner radius r31, and the third outer radius r31 is greater than the third inner radius r31. The radius r32 is larger than the fourth outer radius r42. Thereby, the outer diameter of an encoder can be made small compared with the case where the 1st magnetic flux coupling body 41a and the 2nd magnetic flux coupling body 41b are arranged in the same layer. Further, the second transmission winding 31b can be disposed between the second reception winding 32b and the second magnetic flux coupling body 41b as viewed in the axial direction, and the first magnetic flux coupling body 41a is formed by the second transmission winding 31b. Crosstalk can be suppressed.

  In the example shown in FIG. 3, the first transmission winding 31a is provided in the same layer as the second transmission winding 31b. The second radius r20 is smaller than the second inner radius r21, and the first radius r10 is larger than the first outer radius r12. Thereby, the 1st transmission winding 31a can be arrange | positioned near the 1st magnetic flux coupling body 41a, and the 2nd transmission winding 31b can be arrange | positioned near the 2nd magnetic flux coupling body 41b.

  Next, planar shapes of the first transmission winding 31a, the second transmission winding 31b, the first reception winding 32a, the second reception winding 32b, the first magnetic flux coupling body 41a, and the second magnetic flux coupling body 41b will be described. To do.

FIG. 4 is a plan view illustrating the first transmission winding, the second transmission winding, and the first reception winding.
As shown in FIG. 4, the first transmission winding 31 a is disposed on the side close to the outer periphery of the insulating layer 33 </ b> A, and the second transmission winding 31 b is disposed on the side close to the through hole 34. The lead-out wiring of the second transmission winding 31b is routed between the insulating layer 33B and the insulating layer 33C through a through hole at a position inside the first receiving winding 32a in the insulating layer 33A. As a result, wiring can be performed without increasing the outer diameter of the stator 14 and without interfering with the first receiving winding 32a. Note that the take-out wiring of the second transmission winding 31b may be routed from the through hole 34 side of the second reception winding 32b to the lower layer.

  The first reception winding 32a is disposed at a position close to the first transmission winding 31a between the first transmission winding 31a and the second transmission winding 31b. The first reception winding 32a includes three reception winding portions 321a to 323a having different phases in the rotation direction. The portions of the reception winding portions 321a to 323a that intersect with each other are arranged vertically via the insulating layer 33A and are connected to each other by through holes or vias. Thereby, each is insulated and arranged.

FIG. 5 is a plan view illustrating one receiving winding portion of the first receiving winding.
As shown in FIG. 5, the reception winding portion 321 a has a loop shape (diamond shape) that periodically changes with a pitch λ <b> 1 in the rotation direction of the rotor 15. In the reception winding part 321a, ten rhombus pattern pairs PA1 are provided. The reception winding portions 322a and 323a have the same shape as the reception winding portion 321a.

FIG. 6 is a plan view illustrating the second reception winding.
As shown in FIG. 6, the second receiving winding 32b has the same shape as the first receiving winding 32a, and is configured by three receiving winding portions 321b to 323b having different phases in the rotation direction. Is done. However, the overall size of the second reception winding 32b is smaller than that of the first reception winding 32a. Further, the pitch in the rotation direction of the second reception winding 32b is different from the pitch in the rotation direction of the first reception winding 32a.

FIG. 7 is a plan view illustrating one receiving winding portion of the second receiving winding.
As shown in FIG. 7, the reception winding portion 321 b has a loop shape (diamond shape) that periodically changes in the rotation direction of the rotor 15 with a pitch λ 2 different from the pitch λ 1. For example, the pitch λ2 is longer than the pitch λ1. In other words, the pitch λ1 is shorter than the pitch λ2. Eight rhombus pattern pairs PA2 are provided. The reception winding portions 322b and 323b also have the same shape as the reception winding portion 321b.

FIG. 8 is a plan view illustrating the first magnetic flux coupling body.
As shown in FIG. 8, the first magnetic flux coupling body 41a is formed coaxially with the spindle 7 and is formed so as to overlap the first reception winding 32a with a gap. The first magnetic flux coupling body 41a has a continuous gear-like shape that periodically changes in the rotation direction of the rotor 15 with the same pitch λ1 as that of the first reception winding 32a.

  The first magnetic flux coupling body 41 a alternately includes concave portions 411 a that are recessed in a direction approaching the spindle 7 and convex portions 412 a that protrude in a direction away from the spindle 7. In the example shown in FIG. 8, ten pattern pairs PA3 of the concave portions 411a and the convex portions 412a are provided.

FIG. 9 is a plan view illustrating a second magnetic flux coupling body.
As shown in FIG. 9, the second magnetic flux coupling body 41b is formed coaxially with the spindle 7, and has a gear shape in which concave portions 411b and convex portions 412b similar to the first magnetic flux coupling body 41a are alternately repeated. It has the shape of The pitch of the concave portion 411b and the convex portion 412b of the second magnetic flux coupling body 41b is λ2. In the example shown in FIG. 9, nine pattern pairs PA4 of the concave portions 411b and the convex portions 412b are provided. The first magnetic flux coupling body 41a and the second magnetic flux coupling body 41b may have other shapes such as a gear shape, a sin wave shape, and an island shape.

  The inductive detection type rotary encoder 11 according to the present embodiment having such a configuration can perform highly accurate position detection while suppressing the influence of crosstalk while reducing the outer diameter of the encoder.

[Second Embodiment]
Next, 2nd Embodiment of this invention is described based on drawing.
FIG. 10 is a cross-sectional view illustrating an inductive detection type rotary encoder according to the second embodiment.
11 and 12 are plan views illustrating the magnetic flux coupling body according to the second embodiment.
In the inductive detection type rotary encoder 12 according to the second embodiment, the first magnetic flux coupling body 41a includes a first annular current path 413a, and the second magnetic flux coupling body 41b includes a second annular current path 413b.

  As shown in FIG. 11, the first magnetic flux coupling body 41 a of the inductive detection type rotary encoder 12 according to the second embodiment is provided in an annular shape with the same radius as the third inner radius r <b> 31 around the rotation axis AX. One annular current path 413a is included. A part of the first annular current path 413a is shared with the convex portion 412a.

  In addition, as illustrated in FIG. 12, the second magnetic flux coupling body 41b includes a second annular current path 413b that is annularly provided with the same radius as the fourth outer radius r42 around the rotation axis AX. A part of the second annular current path 413b is shared with the recess 411b.

  In the inductive detection type rotary encoder 12 according to the second embodiment, the configuration other than the first magnetic flux coupling body 41a and the second magnetic flux coupling body 41b is the same as that of the first embodiment. According to the inductive detection type rotary encoder 12 according to the second embodiment, each of the first annular current path 413a and the second annular current path 413b serves as a shield.

  For example, since the first annular current path 413a is provided on the second transmission winding 31b side of the first magnetic flux coupling body 41a, the first magnetic flux coupling body 41a is affected by the magnetic field generated in the second transmission winding 31b. Before receiving, it can be received by the first annular current path 413a. That is, the first annular current path 413a serves as a shield against the magnetic field of the second transmission winding 31b. As a result, the first magnetic flux coupling body 41a is hardly affected by the magnetic field of the second transmission winding 31b, and can sufficiently flow the current due to the magnetic field of the first transmission winding 31a.

  Similarly, since the second annular current path 413b is provided on the first transmission winding 31a side of the second magnetic flux coupling body 41b, the influence of the magnetic field generated in the first transmission winding 31a is affected by the second magnetic flux coupling body 41b. Can be received by the second annular current path 413b. That is, the second annular current path 413b serves as a shield against the magnetic field of the first transmission winding 31a. As a result, the second magnetic flux coupling body 41b is hardly affected by the magnetic field of the first transmission winding 31a, and can sufficiently flow the current due to the magnetic field of the second transmission winding 31b.

  According to the inductive detection type rotary encoder 12 according to the second embodiment, highly accurate position detection is performed with the influence of crosstalk suppressed by the shielding effect of each of the first annular current path 413a and the second annular current path 413b. be able to.

[Third Embodiment]
Next, 3rd Embodiment of this invention is described based on drawing.
FIG. 13 is a cross-sectional view illustrating an inductive detection type rotary encoder according to the third embodiment.
14 and 15 are plan views illustrating the magnetic flux coupling body according to the third embodiment.
The inductive detection type rotary encoder 13 according to the third embodiment includes a first annular current path 413a provided annularly around the rotation axis AX inside the first magnetic flux coupling body 41a, and an outer side of the second magnetic flux coupling body 41b. And a second annular current path 413b provided annularly around the rotation axis AX. That is, the first annular current path 413a is provided in an annular shape independently of the first magnetic flux coupling body 41a, and the second annular current path 413b is provided in an annular shape independently of the second magnetic flux coupling body 41b. Other configurations are the same as those in the first embodiment.

  Even if the first annular current path 413a is provided independently of the first magnetic flux coupling body 41a, the first annular current path 413a serves as a shield against the magnetic field of the second transmission winding 31b as in the second embodiment. Fulfill. Even if the second annular current path 413b is provided independently of the second magnetic flux coupling body 41b, the second annular current path 413b serves as a shield against the magnetic field of the first transmission winding 31a.

  In the third embodiment, since the first annular current path 413a and the second annular current path 413b are provided independently, each of the first magnetic flux coupling body 41a and the second magnetic flux coupling body 41b has the first transmission winding. Current due to the magnetic field from each of the line 31a and the second transmission winding 31b flows efficiently.

  According to the inductive detection type rotary encoder 13 according to the third embodiment, highly accurate position detection is performed in which the influence of crosstalk is suppressed by the shielding effect of each of the first annular current path 413a and the second annular current path 413b. be able to.

  As described above, according to the embodiment, it is possible to provide inductive detection type rotary encoders 11, 12, and 13 that can perform position detection with high accuracy while miniaturizing an encoder and suppressing crosstalk. .

  Although the present embodiment has been described above, the present invention is not limited to these examples. For example, those in which the person skilled in the art appropriately added, deleted, and changed the design of each of the above-described embodiments, and combinations of the features of each embodiment as appropriate, also have the gist of the present invention. As long as it is within the scope of the present invention.

  As described above, the present invention can be suitably used for various measuring instruments such as a digital indicator, which detect a rotation amount and obtain a measurement value, in addition to a digital micrometer.

DESCRIPTION OF SYMBOLS 1 ... Digital micrometer 3 ... Frame 5 ... Thimble 7 ... Spindle 9 ... Display part 11, 12, 13 ... Inductive detection type rotary encoder 14 ... Stator 15 ... Rotor 31a ... 1st transmission winding 31b ... 2nd transmission winding 33A, 33B, 33C, 33D ... insulating layer 41a ... first magnetic flux coupling body 41b ... second magnetic flux coupling body 42A, 42B ... insulating layer R1 ... first region R2 ... second region R3 ... third region R4 ... fourth region

Claims (8)

A stator,
A rotor facing the stator and rotatably provided around a rotation axis;
A first transmission winding provided on the stator and having a first radius around the rotation axis;
A second transmission winding provided on the stator and having a second radius around the rotation axis;
A first receiving winding provided on the stator, formed in an annular first region centered on the rotating shaft, and having a first inner radius and a first outer radius centered on the rotating shaft;
Provided in the stator, formed in an annular second region centered on the rotating shaft, formed with a first insulating layer between the first receiving winding and the first centered on the rotating shaft; A second receiving winding having two inner radii and a second outer radius;
A third region that is provided in the rotor and that is an annular region that is centered on the rotation axis and that overlaps the first region in the axial direction along the rotation axis, and that is centered on the rotation axis. A first magnetic flux coupling body having an inner radius and a third outer radius;
A second insulating layer provided in the rotor and formed in a fourth region that is an annular region centered on the rotation axis and overlaps the second region in the axial direction. A second magnetic flux coupling body having a fourth inner radius and a fourth outer radius about the rotation axis;
With
The second region, the first region, the third region, and the fourth region are arranged in this order in the axial direction,
The shortest distance between the first transmission winding and the first magnetic flux coupling body is shorter than the shortest distance between the second transmission winding and the first magnetic flux coupling body,
The shortest distance between the second transmission winding and the second magnetic flux coupling body is shorter than the shortest distance between the first transmission winding and the second magnetic flux coupling body,
And,
The shortest distance between the first transmission winding and the first magnetic flux coupling body is shorter than the shortest distance between the first transmission winding and the second magnetic flux coupling body. The second transmission winding and the second magnetic flux. An inductive detection type rotary encoder characterized in that a shortest distance to a coupling body is shorter than a shortest distance between the second transmission winding and the first magnetic flux coupling body. The first inner radius is greater than the second inner radius;
The second outer radius is greater than or equal to the first inner radius;
The inductive detection type rotary encoder according to claim 1, wherein the first outer radius is larger than the second outer radius. The third inner radius is greater than the fourth inner radius;
The fourth outer radius is greater than or equal to the third inner radius;
The inductive detection type rotary encoder according to claim 1, wherein the third outer radius is larger than the fourth outer radius. The first radius is greater than the first outer radius;
The inductive detection type rotary encoder according to claim 1, wherein the second radius is smaller than the first inner radius.   The inductive detection type rotary encoder according to any one of claims 1 to 4, wherein the first transmission winding is provided in the same layer as the second transmission winding. The first magnetic flux coupling body and the first reception winding are provided in a shape that periodically changes at a first pitch in a rotation direction around the rotation axis,
The second magnetic flux coupling body and the second receiving winding are provided in a shape that periodically changes at a second pitch different from the first pitch in a rotation direction around the rotation axis. The inductive detection type rotary encoder according to any one of claims 1 to 5. The first magnetic flux coupling body includes a first annular current path provided in an annular shape with the same radius as the third inner radius around the rotation axis,
The second magnetic flux coupling body includes a second annular current path provided in an annular shape with the same radius as the fourth outer radius around the rotation axis. The inductive detection type rotary encoder described in 1. A first annular current path provided in an annular shape around the rotation axis inside the first magnetic flux coupling body;
The induction according to any one of claims 1 to 6, further comprising a second annular current path provided in an annular shape around the rotation axis outside the second magnetic flux coupling body. Detection type rotary encoder.

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