JP2013152163A - Induction detecting type rotary encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact induction detecting type rotary encoder.SOLUTION: An induction detecting type rotary encoder comprises: a first receiving coil and a second receiving coil formed in a stator; and a first magnetic flux coupling coil and a second magnetic flux coupling coil formed on a rotor and respectively flux coupled with the first receiving coil and the second receiving coil. The first receiving coil and the first magnetic flux coupling coil together form a first track having a shape periodically changing at a first pitch along a rotation direction of the rotor. The second receiving coil and the second magnetic flux coupling coil together form a second track having a shape periodically changing at a second pitch along the rotation direction of the rotor. The first receiving coil and the second receiving coil have similar radiuses and are stacked with a first insulating layer sandwiched therebetween along an extending direction of a rotation axis. The first magnetic flux coupling coil and the second magnetic flux coupling coil have similar radiuses and are stacked with a second insulating layer sandwiched therebetween along the extending direction of the rotation axis.

Description

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

  The rotary encoder includes a stator in which a transmission winding and a reception winding are arranged, and a rotor in which a magnetic flux coupling body capable of magnetic flux coupling is arranged (see Patent Document 1). When a rotary encoder is applied to a hand tool such as a micrometer, it is necessary to aggregate a plurality of tracks (transmitting winding, receiving winding, and magnetic flux coupling body) that generate signals having different wavelengths and to reduce the outer diameter thereof. .

JP 2006-322927 A

  An object of the present invention is to provide a miniaturized inductive detection type rotary encoder.

  An inductive detection type rotary encoder according to the present invention includes a stator, a rotor that is rotatable about a rotation axis and disposed opposite to the stator, and a transmission that is annularly formed around the rotation axis in the stator. A winding, a first receiving winding and a second receiving winding formed in an annular shape around the rotation axis along the transmission winding in the stator, and an annular shape around the rotation axis in the rotor A first magnetic flux coupling body and a second magnetic flux coupling body, which are formed to be magnetically coupled to the transmission winding, the first reception winding, and the second reception winding, respectively. The receiving winding and the first magnetic flux coupling body form a first track having a shape that periodically changes in a rotation direction of the rotor with a first pitch, and the second receiving winding and the second magnetic flux coupling body. The magnetic flux coupling body of the first Forming a second track having a shape that periodically changes in a rotation direction of the rotor with a second pitch different from the pitch, and the first reception winding and the second reception winding have the same radius. The first magnetic flux coupling body and the second magnetic flux coupling body are stacked in the extending direction of the rotating shaft with the same radius. It is characterized by being laminated through an insulating layer.

  According to the present invention, a miniaturized inductive detection type rotary encoder can be provided.

1 is a front view of a digital micrometer 1 equipped with an inductive detection type rotary encoder according to a first embodiment. It is sectional drawing of the induction | guidance | derivation detection type | formula rotary encoder 11 which concerns on 1st Embodiment. It is sectional drawing of the stator 13 and the rotor 15 which concern on 1st Embodiment. It is a top view which shows the transmission coil | winding 31 and the 1st receiving coil | winding 32a which concern on 1st Embodiment. It is a top view which shows the receiving winding 321a which concerns on 1st Embodiment. It is a top view which shows the 2nd receiving winding 32b which concerns on 1st Embodiment. It is a top view which shows the receiving winding 321b which concerns on 1st Embodiment. It is a top view which shows the 1st magnetic flux coupling body 41a which concerns on 1st Embodiment. It is a top view which shows the 2nd magnetic flux coupling body 41b which concerns on 1st Embodiment. It is a figure which shows the signal obtained by the 1st and 2nd receiving winding 32a, 32b which concerns on 1st Embodiment. It is sectional drawing which shows the stator 13 and the rotor 15 which concern on 2nd Embodiment. It is a top view which shows the 1st transmission coil | winding 31a and the 1st receiving coil | winding 32a which concern on 2nd Embodiment. It is a top view which shows the 2nd transmission coil | winding 31b and the 2nd receiving coil | winding 32b which concern on 2nd Embodiment. It is a top view which shows the 2nd magnetic flux coupling body 41c which concerns on 2nd Embodiment. It is the schematic which shows the induced current which arises in the 1st, 2nd magnetic flux coupling bodies 41a and 41c by the electric current Id1 which flows through the 1st transmission winding 31a which concerns on 2nd Embodiment. It is the schematic which shows the induced current which arises in the 1st, 2nd magnetic flux coupling bodies 41a and 41c by the electric current Id1 which flows through the 2nd transmission winding 31b which concerns on 2nd Embodiment. It is the schematic which shows the transmission coil | winding 31c which concerns on 3rd Embodiment.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  With reference to FIG. 1, the configuration of a digital micrometer equipped with the inductive detection type rotary encoder according to the first embodiment of the present invention will be described. FIG. 1 is a front view of a digital micrometer. A thimble 5 is rotatably attached to the frame 3 of the digital micrometer. The spindle 7 serving as a measuring element is rotatably supported inside the frame 3.

  One end side of the spindle 7 protrudes to the outside, and this one end comes into contact with the object to be measured. On the other hand, a feed screw (not shown in FIG. 1) is cut on the other end side of the spindle 7. This feed screw is fitted into a nut in the thimble 5.

  In this configuration, when the thimble 5 is rotated in the forward direction, the spindle 7 moves forward along the axial direction of the spindle 7, and when the thimble 5 is rotated in the reverse direction, the spindle 7 moves backward along the axial direction of the spindle 7. The frame 3 is provided with a liquid crystal display unit 9 capable of displaying the measured value of the digital micrometer.

[Configuration of Inductive Detection Type Rotary Encoder 11 According to the First Embodiment]
Next, the configuration of the inductive detection type rotary encoder 11 according to the first embodiment incorporated in the digital micrometer of FIG. 1 will be described with reference to FIG. FIG. 2 is a cross-sectional view of the inductive detection type rotary encoder 11.

  The inductive detection type rotary encoder 11 includes a stator 13 and a rotor 15 that is rotatable about a spindle 7 (rotating shaft) and disposed opposite to the stator 13. The rotor 15 is fixed to an end face of a cylindrical rotor bush 19. The spindle 7 is inserted into the rotor bush 19. The stator bush 21 is fixed to the frame 3.

  A feed screw 23 is formed on the surface of the spindle 7 to be fitted into a nut disposed inside the thimble 5 of FIG. Further, a key groove 25 is dug on the surface of the spindle 7 along the longitudinal direction of the spindle 7 (that is, the forward and backward direction of the spindle 7). The key groove 25 is fitted with the tip of a pin 27 fixed to the rotor bush 19. When the spindle 7 rotates, the rotational force is transmitted to the rotor bush 19 via the pin 27 and the rotor 15 rotates. In other words, 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.

  Next, the configuration of the stator 13 and the rotor 15 will be described with reference to FIG. FIG. 3 is a cross-sectional view of the stator 13 and the rotor 15. As shown in FIG. 3, the stator 13 includes stacked insulating layers 33 </ b> A to 33 </ b> D. The stator 13 includes a transmission winding 31 and a first reception winding 32a in the insulating layer 33A on the rotor 15 side, and a second reception winding 32b in the intermediate insulating layer 33C. The insulating layers 33A to 33D are formed with through holes 34 for passing the spindle 7, and the transmission winding 31, the first reception winding 32a, and the second reception winding 32b have the through holes 34 formed therein. It is formed in an annular shape as the center.

  On the other hand, as shown in FIG. 3, the rotor 15 includes laminated insulating layers 42A and 42B. The rotor 15 includes a first magnetic flux coupling body 41a in the insulating layer 42A, and a second magnetic flux coupling body 41b in the insulating layer 42B. The insulating layers 42A and 42B are formed with through holes 43 through which the spindle 7 passes, and the first magnetic flux coupling body 41a and the second magnetic flux coupling body 41b are formed in an annular shape with the through hole 43 as the center. Has been.

  The transmission winding 31 passes a transmission current whose current direction changes periodically, and applies a magnetic field generated thereby to the first and second magnetic flux coupling bodies 41 a and 41 b formed in the rotor 15. The transmission winding 31 is provided on the surface of the insulating layer 33A on the rotor 15 side.

  The first and second magnetic flux coupling bodies 41 a and 41 b each generate an induced current based on a magnetic field generated by a transmission current flowing through the transmission winding 31. The first magnetic flux coupling body 41a is provided on the surface of the insulating layer 42A on the stator 13 side. The second magnetic flux coupling body 41b is provided on the surface of the insulating layer 42B on the stator 13 side. The first and second magnetic flux coupling bodies 41a and 41b have the same diameter and are stacked at positions overlapping each other in the stacking direction via the insulating layer 42A.

  The first reception winding 32a is generated by the magnetic flux coupling based on the induction current generated in the first magnetic flux coupling body 41a by the magnetic flux coupling between the transmission winding 31 and the first magnetic flux coupling body 41a. Detect induced voltage. The second reception winding 32b is generated by the magnetic flux coupling based on the induced current generated in the second magnetic flux coupling body 41b by the magnetic flux coupling between the transmission winding 31 and the second magnetic flux coupling body 41b. Detect induced voltage.

  A part of the first receiving winding 32a is formed on the surface of the insulating layer 33A on the rotor 15 side, and the remaining part of the first receiving winding 32a is formed on the surface of the insulating layer 33B on the rotor 15 side, Both are connected to each other by through holes or vias penetrating the insulating layer 33A. A part of the second receiving winding 32b is formed on the surface of the insulating layer 33C on the rotor 15 side, and the remaining part of the second receiving winding 32b is formed on the surface of the insulating layer 33D on the rotor 15 side. Are mutually connected by through holes or vias penetrating the insulating layer 33C. The first reception winding 32a and the second reception winding 32b have the same diameter and are stacked at positions overlapping each other in the stacking direction via the insulating layer 33B.

  In FIG. 3, the first receiving winding 32a faces the first magnetic flux coupling body 41a. In addition, the first receiving winding 32a and the first magnetic flux coupling body 41a are arranged between the second receiving winding 32b and the second magnetic flux coupling body 41b. With this arrangement, the signal intensity received by the first reception winding 32a can be increased. This arrangement is preferable when the reception signal of the first reception winding 32a affects the measurement accuracy.

  Next, planar shapes of the transmission winding 31, 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.

  FIG. 4 is a plan view showing the transmission winding 31 and the first reception winding 32a. As shown in FIG. 4, the transmission winding 31 is formed coaxially with the spindle 7 and has a substantially circular current path on the outer peripheral side and the inner peripheral side. The transmission winding 31 is formed so that the direction of the current flowing in the current path on the outer peripheral side of the transmission winding 31 is the same as the direction of the current flowing in the current path on the inner peripheral side of the transmission winding 31 (see arrow). ).

  As shown in FIG. 4, the first reception winding 32 a is formed coaxially with the spindle 7, and is annularly positioned so as to be positioned between the outer and inner current paths of the transmission winding 31. It is formed. The first reception winding 32a includes three reception windings 321a to 323a having different phases in the rotation direction. The receiving windings 321a to 323a are arranged so that the intersecting portions do not short-circuit with each other vertically through the insulating layer 33A, and are mutually insulated and separated by being connected through through holes or via holes. Be placed.

  Next, the shape of the reception winding 321a will be described with reference to FIG. FIG. 5 is a plan view showing the reception winding 321a. As shown in FIG. 5, the reception winding 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 receiving winding 321a, in the example shown in FIG. 5, ten diamond-shaped pairs PA1 are provided. The reception windings 322a and 323a have the same shape as the reception winding 321a.

  Next, the shape of the second reception winding 32b will be described with reference to FIG. FIG. 6 is a plan view showing the second reception winding 32b. As shown in FIG. 6, the second receiving winding 32b is formed coaxially with the spindle 7, and is formed in an annular shape so as to overlap the first receiving winding 32a in the stacking direction. The second reception winding 32b includes three reception windings 321b to 323b having different phases in the rotation direction. The receiving windings 321b to 323b are arranged so that the intersecting portions are not vertically short-circuited via the insulating layer 33C and are insulated and separated by being connected to each other through through holes or via holes. Be placed.

  Next, the shape of the reception winding 321b will be described with reference to FIG. FIG. 7 is a plan view showing the reception winding 321b. As shown in FIG. 7, the reception winding 321b has a loop shape (diamond shape) that periodically changes in the rotation direction of the rotor 15 with a pitch λ2 (λ2 ≠ λ1) different from the pitch λ1. In the receiving winding 321b, nine rhombus-shaped pairs PA2 are provided in the example shown in FIG. In the present embodiment, the pitch λ1 is shorter than the pitch λ2 (λ1 <λ2). The reception windings 322b and 323b have the same shape as the reception winding 321b.

  Next, the shape of the first magnetic flux coupling body 41a will be described with reference to FIG. FIG. 8 is a plan view showing the first magnetic flux coupling body 41a. 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 receiving 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 pairs PA3 of the concave portion 411a and the convex portion 412a are provided.

  Next, the shape of the second magnetic flux coupling body 41b will be described with reference to FIG. FIG. 9 is a plan view showing the second magnetic flux coupling body 41b. As shown in FIG. 9, the second magnetic flux coupling body 41b is formed coaxially with respect to the spindle 7, and is formed to overlap the first magnetic flux coupling body 41a and the insulating layer 42A in the stacking direction. . The second magnetic flux coupling body 41b has a continuous gear-like shape that periodically changes in the rotation direction of the rotor 15 with a pitch λ2. The second magnetic flux coupling body 41 b alternately includes concave portions 411 b that are recessed in a direction approaching the spindle 7 and convex portions 412 b that protrude in a direction away from the spindle 7. In the example shown in FIG. 9, nine pairs PA4 of the concave portion 411b and the convex portion 412b are provided.

  3 to 9, the first receiving winding 32a and the first magnetic flux coupling body 41a have the first track having a shape that periodically changes in the rotation direction of the rotor 15 with the pitch λ1. Form. The second receiving winding 32b and the second magnetic flux coupling body 41b form a second track having a shape that periodically changes in the rotation direction of the rotor 15 with a pitch λ2 different from the pitch λ1. In the present embodiment, since the pitch λ1 of the first track is shorter than the pitch λ2 of the second track, the first track affects the measurement accuracy more than the second track. Since the signal intensity of the first track at the pitch λ1 is higher than the signal intensity of the second track, high measurement accuracy can be obtained.

  Next, with reference to FIG. 10, signals obtained by the first reception winding 32a and the second reception winding 32b will be described. When a current flows clockwise in the current paths on the outer peripheral side and the inner peripheral side of the transmission winding 31 as shown in FIG. 4, for example, a magnetic field is generated in the right-handed direction in each current path. Coupled with the first and second magnetic flux coupling bodies 41a and 41b, a current flows counterclockwise through the first and second magnetic flux coupling bodies 41a and 41b. Accordingly, the concave portions 411a and 411b of the first and second magnetic flux coupling bodies 41a and 41b proceed from the front surface to the rear surface in FIGS. 8 and 9, and the convex portions 412a and 412b proceed from the rear surface to the front surface. Magnetic field is generated. These magnetic fields are received by the first and second receiving windings 32a and 32b. Not only the magnetic field from the first magnetic flux coupling body 41a but also the magnetic field from the second magnetic flux coupling body 41b is coupled to the first reception winding 32a. However, the first magnetic flux coupling body 41a has a pitch of λ1 × 10 while the second magnetic flux coupling body 41b has a pitch of λ2 × 9. The influence of the magnetic field coupled to the first receiving winding 32a is due to the magnetic field from the first magnetic flux coupling body 41a being offset by the influence of the magnetic field from the second magnetic flux coupling body 41b in total for one turn. Only the impact. Thereby, a reception signal determined only by the coupling phase with the first magnetic flux coupling body 41a is obtained in the first reception winding 32a. Similarly, a reception signal determined only by the coupling phase with the second magnetic flux coupling body 41b is obtained in the second reception winding 32b. As described above, the induced voltage caused by the second magnetic flux coupling body 41b cancels out in the first reception winding 32a with different pitches λ1 and λ2, and thus the signal is not detected. That is, the first receiving winding 32a can suppress crosstalk from the second magnetic flux coupling body 41b, and the second receiving winding 32b can suppress crosstalk from the first magnetic flux coupling body 41a. be able to.

  As a result, as shown in FIG. 10, a reception signal that varies depending on the position of the rotor 15 with respect to the stator 13 is obtained from the first reception winding 32a and the second reception winding 32b. Since both the received signals are shifted by one turn while the rotor 15 makes one rotation, the absolute position in one rotation can be detected from the two received signals. Note that FIG. 10 shows only a signal for one phase, but actually, three-phase received signals shifted by 120 ° are obtained.

  As described above, according to the present embodiment, the first and second receiving windings 32a and 32b can be stacked via the insulating layer in the longitudinal direction of the spindle 7, and the first and second magnetic flux coupling bodies 41a. 41b can also be stacked in the longitudinal direction of the spindle 7 via an insulating layer, so that the outer diameter of the encoder can be reduced. Moreover, there is no crosstalk.

[Second Embodiment]
Next, with reference to FIG. 11, the stator 13 and the rotor 15 which concern on 2nd Embodiment are demonstrated. FIG. 11 is a sectional view showing the stator 13 and the rotor 15 according to the second embodiment. As shown in FIG. 11, the stator 13 according to the second embodiment includes a first transmission winding 31a and a second transmission winding 31b. In this respect, the first embodiment having only one transmission winding 31 is different from the second embodiment. The second magnetic flux coupling body 41c provided on the rotor 15 has a shape different from that of the first embodiment. In addition, since the first and second receiving windings 32a and 32b, the first magnetic flux coupling body 41a, and the like according to the second embodiment are the same as those in the first embodiment, description thereof is omitted.

  The first transmission winding 31a flows a transmission current whose current direction changes periodically, and gives a magnetic field generated thereby to the first magnetic flux coupling body 41a. The second transmission winding 31b flows a transmission current whose current direction changes periodically, and applies a magnetic field generated thereby to the second magnetic flux coupling body 41c. Supply of current to the first and second transmission windings 31a and 31b is performed at different timings.

  As shown in FIG. 11, the first transmission winding 31a is formed on the surface of the insulating layer 33A on the rotor 15 side. The second transmission winding 31b is formed on the surface of the insulating layer 33C on the rotor 15 side.

  Next, the shape of the first transmission winding 31a will be described with reference to FIG. FIG. 12 is a plan view showing the first transmission winding 31a and the first reception winding 32a. As shown in FIG. 12, the first transmission winding 31a is formed coaxially with the spindle 7 and has substantially circular current paths on the outer peripheral side and the inner peripheral side. The first transmission winding so that the direction of the current flowing in the current path on the outer peripheral side of the first transmission winding 31a is the same as the direction of the current flowing in the current path on the inner peripheral side of the first transmission winding 31a. A line 31a is formed (see arrow). The first reception winding 32a is disposed between the current paths on the outer peripheral side and the inner peripheral side of the first transmission winding 31a.

  Next, the shape of the second transmission winding 31b will be described with reference to FIG. FIG. 13 is a plan view showing the second transmission winding 31b and the second reception winding 32b. As shown in FIG. 13, the second transmission winding 31b is formed coaxially with the spindle 7 and has substantially circular current paths on the outer peripheral side and the inner peripheral side. The second transmission winding so that the direction of the current flowing in the current path on the outer peripheral side of the second transmission winding 31b is opposite to the direction of the current flowing in the current path on the inner peripheral side of the second transmission winding 31b. Line 31b is formed (see arrow). A second reception winding 32b is disposed between the current paths on the outer peripheral side and the inner peripheral side of the second transmission winding 31b.

  Next, the shape of the second magnetic flux coupling body 41c will be described with reference to FIG. FIG. 14 is a plan view showing the second magnetic flux coupling body 41c. As shown in FIG. 14, the second magnetic flux coupling body 41 c is formed coaxially with the spindle 7, and is an island like a plurality of isolated rectangular loops arranged at a constant pitch λ2 in the rotation direction of the rotor 15. It is formed in a shape. In the example shown in FIG. 14, nine second magnetic flux coupling bodies 41c are provided. In addition, since the shape of the 1st magnetic flux coupling body 41a which concerns on 2nd Embodiment is the same as that of 1st Embodiment, the description is abbreviate | omitted.

  Next, an induced current generated in the first and second magnetic flux coupling bodies 41a and 41c by the current Id1 flowing through the first transmission winding 31a will be described with reference to FIG. In the example shown in FIG. 15, the current Id1 flows clockwise in the current path on the outer peripheral side of the first transmission winding 31a. In this case, the current Id1 flows clockwise also in the current path on the inner peripheral side of the first transmission winding 31a. Thereby, in the current paths on the outer peripheral side and the inner peripheral side of the first and second magnetic flux coupling bodies 41a and 41c, the induced current Id2 flows counterclockwise. Therefore, an induced current is generated in the entire current path of the first magnetic flux coupling body 41a due to its shape. On the other hand, since the induced currents Id2 flowing through the current paths on the outer peripheral side and the inner peripheral side of the second magnetic flux coupling body 41c cancel each other out of the shape, the induced current is substantially reduced in the entire current path of the second magnetic flux coupling body 41c. Does not occur.

  Next, an induced current generated in the first and second magnetic flux coupling bodies 41a and 41c by the current Id1 flowing through the second transmission winding 31b will be described with reference to FIG. In the example shown in FIG. 16, the current Id1 flows clockwise in the current path on the outer peripheral side of the second transmission winding 31b. In this case, the current Id1 flows counterclockwise in the current path on the inner peripheral side of the second transmission winding 31b. As a result, in the current path on the outer peripheral side of the first and second magnetic flux coupling bodies 41a and 41c, the induced current Id2 flows counterclockwise, and on the inner circumferential side of the first and second magnetic flux coupling bodies 41a and 41c. In the current path, the induced current Id2 flows clockwise. Therefore, since the induced currents Id2 flowing through the current paths on the outer peripheral side and the inner peripheral side of the first magnetic flux coupling body 41a cancel each other out of the shape, the induced current is substantially reduced in the entire current path of the first magnetic flux coupling body 41a. Does not occur. On the other hand, an induced current is generated in the entire current path of the second magnetic flux coupling body 41c due to its shape.

  Here, in the first embodiment, if the arrangement of the stator and rotor (alignment, shaft eccentricity, inclination, etc.) is not accurately matched, crosstalk occurs and measurement accuracy deteriorates. On the other hand, in the second embodiment, as shown in FIGS. 15 and 16, no induced current is generated in the second magnetic flux coupling body 41c by the current Id1 flowing through the first transmission winding 31a. No induced current is generated in the first magnetic flux coupling body 41a by the current Id1 flowing through the second transmission winding 31b. That is, even if the pitch is not adjusted accurately, in the second embodiment, the current is alternately passed through the first transmission winding 31a and the second transmission winding 31b, so that the first embodiment is more effective than the first embodiment. Crosstalk is suppressed and measurement accuracy can be improved. The second embodiment also has the same effect as the first embodiment.

[Third Embodiment]
Next, an inductive detection type rotary encoder according to a third embodiment will be described. In the third embodiment, the first and second transmission windings 31a and 31b of the second embodiment are replaced with one transmission winding 31c, and the direction in which the current flows is switched. The transmission winding 31c is for supplying a first and second magnetic flux coupling bodies 41a and 41c with a transmission current in which the current direction changes periodically and generating a magnetic field generated thereby. In addition, the third embodiment has the same configuration as that of the second embodiment. Therefore, hereinafter, only the transmission winding 31c and its peripheral circuit according to the third embodiment will be described with reference to FIG.

  As shown in FIG. 17, the rotary encoder of the present embodiment includes switches S1 and S2 for reversing the direction of the current flowing in the current path on the inner peripheral side of the transmission winding 31c. By switching the switches S1 and S2, the transmission winding 31c can be set to the state A shown in FIG. 17B and the state B shown in FIG. In the state A shown in FIG. 17B, the direction of the current flowing through the path on the outer peripheral side of the transmission winding 31c is the same as the direction of the current flowing through the path on the inner peripheral side of the transmission winding 31c (see arrows). . In the state B shown in FIG. 17C, the direction of the current flowing through the path on the outer peripheral side of the transmission winding 31c is opposite to the direction of the current flowing through the path on the inner peripheral side of the transmission winding 31c (see arrow). . The transmission winding 31c is arranged with the first and second reception windings 32a and 32b between the current paths on the inner peripheral side and the outer peripheral side, similarly to the transmission winding 31 according to the first embodiment. doing. The first and second transmission windings 31a and 31b in the second embodiment are provided on the surface of the insulating layers 33A and 33C on the rotor 15 side, whereas the transmission winding in the third embodiment. The current paths on the inner peripheral side and the outer peripheral side of 31c are provided only on the surface of the insulating layer 33A on the rotor 15 side in order to obtain higher signal strength.

  As described above, the third embodiment has the same effects as those of the second embodiment. In addition, since the third embodiment has only one transmission winding 31c, the configuration around the winding is simplified compared to the second embodiment having two transmission windings 31a and 31b. Can be The current paths on the inner and outer peripheral sides of the transmission winding 31c may be provided only on the surface of the insulating layer 33C on the rotor 15 side. Further, the current path on the inner peripheral side of the transmission winding 31c may be provided on the surface of the insulating layer 33A on the rotor 15 side, and the current path on the outer peripheral side of the transmission winding 31c may be provided on the surface of the insulating layer 33C on the rotor 15 side. good. Alternatively, the current path on the outer peripheral side of the transmission winding 31c may be provided on the surface of the insulating layer 33A on the rotor 15 side, and the current path on the inner peripheral side of the transmission winding 31c may be provided on the surface of the insulating layer 33C on the rotor 15 side. Good.

  Although the embodiments of the invention have been described above, the present invention is not limited to these embodiments, and various modifications and additions can be made without departing from the spirit of the invention. For example, the second reception winding 32b faces the second magnetic flux coupling body 41b, and the second reception winding 32b and the second magnetic flux coupling body 41a are interposed between the first reception winding 32a and the first magnetic flux coupling body 41a. Two magnetic flux coupling bodies 41b may be arranged. The second reception winding 32b faces the first magnetic flux coupling body 41a, and the second reception winding 32b and the second magnetic flux coupling body 41b are interposed between the first reception winding 32a and the second magnetic flux coupling body 41b. One magnetic flux coupling body 41a may be arranged. The first reception winding 32a faces the second magnetic flux coupling body 41b. Between the second reception winding 32b and the first magnetic flux coupling body 41a, the first reception winding 32a and the first magnetic flux coupling body 41a are arranged. Two magnetic flux coupling bodies 41b may be arranged.

  Further, the transmission winding 31 in the first embodiment may have a shape having a current path only on the outer peripheral side or only on the inner peripheral side. The second transmission winding 31b in the second embodiment may be formed on the surface of the insulating layer 33B on the rotor 15 side.

DESCRIPTION OF SYMBOLS 3 ... Frame, 5 ... Thimble, 7 ... Spindle, 9 ... Liquid crystal display part, 11 ... Inductive detection type rotary encoder, 13 ... Stator, 15 ... Rotor, 19 ... Rotor bush, 21 ... Stator bush, 23 ... Feed screw, 25 ... key groove, 27 ... pin, 31, 31c ... transmission winding, 31a ... first transmission winding, 31b ... second transmission winding, 32a ... first reception winding, 32b ... second reception winding Lines, 33A to 33D ... insulating layer, 41a ... first magnetic flux coupling body, 41b, 41c ... second magnetic flux coupling body, 42A, 42B ... insulating layer.

Claims (5)

A stator,
A rotor that is rotatable about a rotation axis and disposed opposite the stator;
A transmission winding formed in an annular shape around the rotation axis in the stator;
A first reception winding and a second reception winding formed in an annular shape around the rotation axis along the transmission winding in the stator;
A first magnetic flux coupling body and a second magnetic flux which are annularly formed around the rotation axis of the rotor and are magnetically coupled to the transmission winding, the first reception winding, and the second reception winding, respectively. A combined body,
The first reception winding and the first magnetic flux coupling body form a first track having a shape that periodically changes in a rotation direction of the rotor with a first pitch,
The second receiving winding and the second magnetic flux coupling body form a second track having a shape that periodically changes in a rotation direction of the rotor with a second pitch different from the first pitch,
The first reception winding and the second reception winding are stacked with a similar radius through a first insulating layer in a direction in which the rotation shaft extends,
The first magnetic flux coupling body and the second magnetic flux coupling body are laminated with a similar radius in a direction in which the rotating shaft extends through a second insulating layer. Encoder. The transmission winding comprises a first transmission winding and a second transmission winding having a similar radius,
The first transmission winding has a current path on the outer peripheral side and a current path on the inner peripheral side, and surrounds the first reception winding with these current paths,
The second transmission winding has a current path on the outer peripheral side and a current path on the inner peripheral side, and surrounds the second reception winding with these current paths,
The direction of the current flowing in the current path on the outer peripheral side of the first transmission winding is the same as the direction of the current flowing in the current path on the inner peripheral side of the first transmission winding,
The direction of the current flowing in the current path on the outer peripheral side of the second transmission winding is opposite to the direction of the current flowing in the current path on the inner peripheral side of the second transmission winding,
The first magnetic flux coupling body is continuously formed in a gear shape,
The inductive detection type rotary encoder according to claim 1, wherein the second magnetic flux coupling body is divided into islands. The transmission winding has a current path on the outer peripheral side and a current path on the inner peripheral side, and surrounds the first reception winding and the second reception winding by these current paths, and has a connection relationship with the first. It is configured to be switchable between the first state and the second state,
In the first state, the direction of the current flowing through the current path on the outer peripheral side of the first transmission winding is the same as the direction of current flowing through the current path on the inner peripheral side of the transmission winding;
In the second state, the direction of the current flowing through the current path on the outer peripheral side of the transmission winding is opposite to the direction of the current flowing through the current path on the inner peripheral side of the transmission winding;
The first magnetic flux coupling body is continuously formed in a gear shape,
The inductive detection type rotary encoder according to claim 1, wherein the second magnetic flux coupling body is divided into islands. The first receiving winding is opposed to the first magnetic flux coupling body,
The first receiving winding and the first magnetic flux coupling body are arranged between the second receiving winding and the second magnetic flux coupling body. Item 6. The inductive detection type rotary encoder according to item 3. The inductive detection type rotary encoder according to claim 4, wherein the first pitch is shorter than the second pitch.

Images