JP6133589B2 - Inductive detection type rotary encoder - Google Patents

Description

  The present invention relates to an induction detection type rotary encoder that detects a change in a physical quantity associated with rotation of a rotor relative to a stator and measures a rotation angle of an object based on the change.

  The inductive detection type rotary encoder includes a stator in which a transmission winding and a reception winding are disposed, and a rotor in which a magnetic flux coupling body that is magnetically coupled with these is disposed. In this inductive detection type rotary encoder, at least four tracks or more are required to measure the absolute position (see, for example, Patent Document 1).

  However, when the four tracks are arranged concentrically as in Patent Document 1, the outer diameter of the induction detection type rotary encoder becomes large.

JP 2011-85504 A

  The present invention has been made in view of such problems, and an object thereof 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 first rotor that is engaged with a rotation shaft and rotates together with the rotation shaft, and faces the stator in the axial direction, and an outer peripheral side of the first rotor. A second rotor arranged and rotatable with respect to the first rotor and facing the stator in the axial direction; and transmitting the rotation of the rotary shaft to make the second rotor different from the first rotor A rotation transmitting means that rotates at a speed; a first surface of the stator that is coaxially formed with respect to the rotating shaft and having an equivalent diameter on the facing surface of the first rotor of the stator and the facing surface of the stator of the first rotor; The angle detection track, the second angle detection track, the opposing surface of the second rotor of the stator, and the opposing surface of the stator of the second rotor have the same diameter and are coaxial with the rotating shaft A third angle detection track and a fourth angle detection track formed, and the first angle detection track generates a periodic change of N1 times in one rotation of the first rotor, The second angle detection track generates N2 periodic changes per revolution of the first rotor, and the third angle detection track is N3 periodic changes per revolution of the second rotor. A change is generated, and the fourth angle detection track generates N4 periodic changes in one rotation of the second rotor, wherein N1 is different from N2 and N3 is different from N4.

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

It is sectional drawing which shows the micrometer head 1 which concerns on 1st Embodiment. 3 is a perspective view of a first rotor 42 and a second rotor 51 that constitute the inductive detection type rotary encoder 4 according to the same embodiment. FIG. 4 is an exploded perspective view of a first rotor 42 and a second rotor 51 that constitute the same inductive detection type rotary encoder 4. FIG. It is sectional drawing of the stator 41 and the rotors 42 and 51 which concern on the embodiment. FIG. 4 is a plan view showing first to third transmission windings 412a to 412c, a first reception winding 413a, and a third reception winding 413c according to the same embodiment. It is a top view which shows receiving winding 413aa and 413ca which concerns on the same embodiment. It is a top view which shows the 2nd receiving winding 413b and the 4th receiving winding 413d which concern on the embodiment. It is a top view which shows receiving winding 413ba and 413da which concern on the embodiment. It is a top view which shows the 1st magnetic flux coupling body 422a which concerns on the same embodiment. It is a top view which shows the 3rd magnetic flux coupling body 512a which concerns on the same embodiment. It is a top view which shows the 2nd magnetic flux coupling body 422b which concerns on the same embodiment. It is a top view which shows the 4th magnetic flux coupling body 512b which concerns on the same embodiment. It is a circuit diagram which shows the electric current supply means to the 1st-3rd transmission winding 412a-412c which concerns on the same embodiment. It is the schematic which shows the induced current which arises in the 1st-4th magnetic flux coupling body 422a, 422b, 512a, 512b by the electric current which flows through the 2nd transmission winding 412b which concerns on the embodiment. It is the schematic which shows the induced current which arises in the 1st-4th magnetic flux coupling bodies 422a, 422b, 512a, 512b by the current which flows through the 1st and 3rd transmission windings 412a, 412c concerning the embodiment. It is a figure which shows the signal obtained by the 1st-4th receiving winding 413a-413d which concerns on the same embodiment. It is a block diagram which shows the structure of the transmission / reception control part 6 and the arithmetic processing part 7 of 1st Embodiment. It is sectional drawing which shows the micrometer head 1a which concerns on 2nd Embodiment. It is a disassembled perspective view of the induction | guidance | derivation detection type rotary encoder 4a of 2nd Embodiment. It is a circuit diagram which shows the electric current supply means to the 1st-3rd transmission windings 412a-412c which concern on 3rd Embodiment. It is a block diagram which shows the structure of the transmission / reception control part 6 and the arithmetic processing part 7 of 3rd Embodiment.

  Hereinafter, an embodiment of an inductive detection type rotary encoder according to the present invention will be described with reference to the drawings.

[First Embodiment]
First, an overall configuration of a micrometer head 1 equipped with an inductive detection type rotary encoder 4 according to a first embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a micrometer head 1 according to a first embodiment.

  The micrometer head 1 includes a main body 2, a spindle 3 extending from the main body 2, and an inductive detection type rotary encoder 4 provided around the spindle 3. The micrometer head 1 includes a transmission / reception control unit 6, an arithmetic processing unit 7, and a display unit 8. The transmission / reception control unit 6 controls transmission / reception with the induction detection type rotary encoder 4. The arithmetic processing unit 7 executes arithmetic processing based on a signal from the transmission / reception control unit 6 (inductive detection type rotary encoder 4). The display unit 8 displays the calculation result by the calculation processing unit 7.

  The main body 2 is formed in a substantially cylindrical shape and includes storage spaces 21 and 22 therein. The storage spaces 21 and 22 are partitioned by a partition plate 23. Through holes 24 and 25 through which the spindle 3 passes are respectively formed in the wall on the spindle front end side (left side in the figure) of the substantially cylindrical main body 2 and the partition plate 23, and the base end side (see FIG. A female screw 26 is formed at the end of the middle and right side. The through holes 24 and 25 and the female screw 26 are arranged coaxially.

  The spindle 3 is formed in a substantially cylindrical shape, has a contact surface 31 with an object to be measured (not shown) at a distal end portion, and a knob portion 32 at a proximal end portion. The knob portion 32 is for rotating the spindle 3 from the outside. The spindle 3 is inserted into the through holes 24 and 25 of the main body 2, and both ends protrude from the main body 2. A feed screw 33 is formed on the outer periphery of the spindle 3 and is screwed to the female screw 26 of the main body 2. In this way, when the knob portion 32 is rotated, the spindle 3 is advanced and retracted along the through holes 24 and 25 by the screwing of the feed screw 33 and the female screw 26. The feed screw 33 is formed, for example, for 40 rotations at a pitch of 0.5 mm, and can move the spindle 3 forward and backward by 20 mm. Further, a linear key groove 34 is formed in the substantially central portion of the spindle 3 along the axial direction.

  Next, the configuration of the first rotor 42 and the second rotor 51 constituting the inductive detection type rotary encoder 4 will be described with reference to FIGS. FIG. 2 is a perspective view of the first rotor 42 and the second rotor 51 that constitute the inductive detection type rotary encoder 4. FIG. 3 is an exploded perspective view of the inductive detection type rotary encoder 4. As shown in FIG. 1, the inductive detection type rotary encoder 4 includes a first rotary encoder 40 and a second rotary encoder 50, and is stored in the storage space 22 of the main body 2.

  The first rotary encoder 40 includes a stator 41, a first rotor 42, and a first rotating cylinder 43.

  The stator 41 has an insertion hole 44 through which the spindle 3 is inserted in the center of the disk, and is fixed to the partition plate 23. Specifically, the stator 41 is externally fitted to an edge member 27 formed around the through hole 25 of the partition plate 23.

  The first rotor 42 has an insertion hole 45 through which the spindle 3 is inserted in the center of the disk, and is disposed opposite to the stator 41 by a predetermined dimension and facing the stator 41 in the axial direction.

  The first rotating cylinder 43 is disposed closer to the tip of the spindle 3 than the stator 41 in a state where the spindle 3 is inserted through the first rotating cylinder 43, and the first rotor 42 is arranged around the axis of the spindle 3. It is rotatably supported. That is, the rotor support portion 46 is formed along the outer periphery of the spindle 3 at the end portion of the first rotating cylinder 43 on the stator 41 side, and the first rotor 42 is fitted on the outer periphery of the rotor support portion 46. ing.

  The first rotating cylinder 43 includes a screw-like key 47 screwed from the outer periphery toward the center. The tip of the key 47 protrudes from the inner periphery of the first rotating cylinder 43 and engages with the key groove 34 on the outer periphery of the spindle 3. That is, when the spindle 3 rotates, the key 47 is engaged with the key groove 34 of the spindle 3, so that the first rotating cylinder 43 rotates in synchronization with the spindle 3.

  A first gear 48 is formed on the outer periphery of the first rotating cylinder 43. The gear 48 is provided at the end of the first rotating cylinder 43 on the tip side of the spindle 3 and has a larger outer diameter than the outer periphery of the other part of the rotating cylinder 43. The number of teeth of the first gear 48 is set to 40, for example.

  The second rotary encoder 50 includes the aforementioned stator 41, the second rotor 51, a second rotating cylinder (holding body) 52, and a relay gear 53.

  The stator 41 is the stator 41 of the first rotary encoder 40 and is a component common to the rotary encoders 40 and 50.

  The 2nd rotor 51 has the hole 54 which can arrange | position the 1st rotor 42 in the center of a disc, and is arrange | positioned so that the outer periphery of the said 1st rotor 42 may surround it. Similarly to the first rotor 42, the second rotor 51 is disposed so as to face the stator 41 in the axial direction at a position separated from the stator 41 by a predetermined dimension. In this way, the surfaces of the rotors 42 and 51 facing the stator 41 form substantially the same plane.

  The second rotating cylinder 52 is supported by the first rotating cylinder 43 with the first rotating cylinder 43 (excluding the first gear 48) inserted therein. A second rotor 51 is affixed to the end of the second rotating cylinder 52 on the stator 41 side. In this way, the second rotor 51 is supported so as to be rotatable around the spindle 3. That is, the first rotor 42 and the second rotor 51 are disposed on the inner side and the outer side, respectively, to form a double cylindrical structure.

  A second gear 55 is formed on the outer periphery of the second rotating cylinder 52. The gear 55 is provided at the end of the spindle 3 in the second rotating cylinder 52 and has substantially the same outer diameter as the gear 48 of the first rotating cylinder 43. The number of teeth of the second gear 55 is set to 41, for example, and is larger by one than the number of teeth of the first gear 48.

  The relay gear 53 is rotatably supported by the main body 2 and is disposed in a state where it is engaged with both the first gear 48 and the second gear 55. That is, the relay gear 53 includes a first relay gear 53A that meshes with the first gear 48, a second relay gear 53B that meshes with the second gear 55, and these relay gears 53A and 53B on the same axis. And a shaft portion 53 </ b> C that pivotally supports the shaft. The number of teeth of the relay gears 53A and 53B is set to the same number, for example, 12 pieces. Here, the modules of the first gear 48 and the first relay gear 53A that form a pair of gears coincide with each other, and the modules of the second gear 55 and the second relay gear 53B that form the other pair of gears. The modules also coincide with each other, so that when the first rotating cylinder 43 rotates, the second rotating cylinder 52 can smoothly rotate via the relay gear 53.

  At this time, due to the difference in the number of teeth between the gear 48 and the gear 55, the rotors 42 and 51 rotate at different speeds. For example, when the number of teeth of the gear 48 is 40 and the number of teeth of the gear 55 is 41 as in the present embodiment, the first rotation is performed while the spindle 3 rotates 40 times within the advancing / retreating movement range. The rotor 42 rotates 40 times, and the second rotor 51 rotates 39 times.

  Further, the first rotary encoder 40 and the second rotary encoder 50 can detect an absolute angle within one rotation of the respective rotors 42 and 51. That is, the stator 41 outputs a phase signal indicating a change in one cycle per rotation of the first rotor 42. Since the first rotor 42 rotates in synchronization with the spindle 3, the phase signal related to the first rotor 42 indicates a change in the first cycle of the present invention by one rotation of the spindle 3. For example, a change of 40 cycles is shown while the spindle 3 rotates 40 times.

  The stator 41 also outputs a phase signal indicating a change in one cycle per rotation for the second rotor 51. Since the second rotor 51 rotates 39 times while the spindle 3 rotates 40 times, the phase signal related to the second rotor 51 shows a change of 39 cycles due to 40 rotations of the spindle 3.

  Next, the configuration of the stator 41, the first rotor 42, and the second rotor 51 will be described with reference to FIG. FIG. 4 is a cross-sectional view of the stator 41, the first rotor 42, and the second rotor 51.

  As illustrated in FIG. 4, the stator 41 includes stacked insulating layers 411 </ b> A to 411 </ b> D. The stator 41 has first to third transmission windings 412a to 412c on the surface of the insulating layer 411A on the rotors 42 and 51 side. The first to third transmission windings 412 a to 412 c are formed in an annular shape around the insertion hole 44.

  Further, the stator 41 has a first reception winding 413a on the insulating layer 411A on the rotor 42, 51 side, and a second reception winding 413b on the intermediate insulating layer 411C. The stator 41 has a third reception winding 413c in the insulating layer 411A and a fourth reception winding 413d in the insulating layer 411C. Part of the first and third reception windings 413a and 413c is formed on the surface of the insulating layer 411A on the rotor 42 and 51 side, and the remaining part of the first and third reception windings 413a and 413c is insulated. It is formed on the surface of the layer 411B on the side of the rotors 42 and 51, and both are connected to each other by through holes or vias that penetrate the insulating layer 411A. Part of the second and fourth reception windings 413b and 413d is formed on the surface of the insulating layer 411C on the rotor 42 and 51 side, and the remaining part of the second and fourth reception windings 413b and 413d is the insulation layer. 411D is formed on the surface of the rotors 42 and 51, and both are connected to each other by through holes or vias penetrating the insulating layer 411C.

  The first to fourth reception windings 413 a to 413 d are formed in an annular shape with the insertion hole 44 as the center. The first and second receiving windings 413a and 413b have the same diameter and are stacked at positions overlapping each other in the stacking direction via the insulating layer 411B. The third and fourth reception windings 413c and 413d are provided closer to the outer periphery of the stator 41 than the first and second reception windings 413a and 413b. The third and fourth reception windings 413c and 413d have the same diameter and are stacked at positions overlapping each other in the stacking direction via the insulating layer 411B.

  On the other hand, the first rotor 42 has laminated insulating layers 421A and 421B as shown in FIG. The first rotor 42 has a first magnetic flux coupling body 422a on the surface of the insulating layer 421A on the stator 41 side, and has a second magnetic flux coupling body 422b on the surface of the insulating layer 421B on the stator 41 side. The first magnetic flux coupling body 422a and the second magnetic flux coupling body 422b are formed in an annular shape with the insertion hole 45 as the center. The first and second magnetic flux coupling bodies 422a and 422b have the same diameter and are stacked at positions overlapping each other in the stacking direction via the insulating layer 421A.

  As shown in FIG. 4, the second rotor 51 includes stacked insulating layers 511A and 511B. The second rotor 51 has a third magnetic flux coupling body 512a on the surface of the insulating layer 511A on the stator 41 side, and has a fourth magnetic flux coupling body 512b on the surface of the insulating layer 511B on the stator 41 side. The third magnetic flux coupling body 512 a and the fourth magnetic flux coupling body 512 b are formed in an annular shape with the hole 54 as the center. The third and fourth magnetic flux coupling bodies 512a and 512b have the same diameter and are stacked at positions overlapping each other in the stacking direction via the insulating layer 511A.

  The first to third transmission windings 412a to 412c flow a transmission current whose current direction changes periodically in a time-sharing manner, and generate a magnetic field generated thereby by the first to fourth magnetic flux coupling bodies 422a, 422b, and 512a. 512b.

  The first and second magnetic flux coupling bodies 422a and 422b generate an induced current based on the magnetic field generated by the transmission current flowing through the first and second transmission windings 412a and 412b. The third and fourth magnetic flux coupling bodies 512a and 512b generate an induced current based on the magnetic field generated by the transmission current flowing through the second and third transmission windings 412b and 412c.

  The first reception winding 413a has a magnetic flux coupling based on an induced current generated in the first magnetic flux coupling body 422a by the magnetic flux coupling between the second transmission winding 412b and the first magnetic flux coupling body 422a. The induced voltage generated by is detected. The second reception winding 413b has a magnetic flux coupling based on an induced current generated in the second magnetic flux coupling body 422b by the magnetic flux coupling between the first transmission winding 412a and the second magnetic flux coupling body 422b. The induced voltage generated by is detected.

  The third reception winding 413c has a magnetic flux coupling based on an induced current generated in the third magnetic flux coupling body 512a by the magnetic flux coupling between the third transmission winding 412c and the third magnetic flux coupling body 512a. The induced voltage generated by is detected. The fourth reception winding 413d has a magnetic flux coupling based on an induction current generated in the fourth magnetic flux coupling body 512b by the magnetic flux coupling between the second transmission winding 412b and the fourth magnetic flux coupling body 512b. The induced voltage generated by is detected.

  In FIG. 4, the first receiving winding 413a faces the first magnetic flux coupling body 422a. Further, the first reception winding 413a and the first magnetic flux coupling body 422a are arranged between the second reception winding 413b and the second magnetic flux coupling body 422b. With this arrangement, the signal intensity received by the first reception winding 413a can be increased. This arrangement is preferable when the reception signal of the first reception winding 413a affects the measurement accuracy.

  Similarly, in FIG. 4, the third reception winding 413 c faces the third magnetic flux coupling body 512 a. Further, the third reception winding 413c and the third magnetic flux coupling body 512a are arranged between the fourth reception winding 413d and the fourth magnetic flux coupling body 512b. With this arrangement, the signal strength received by the third reception winding 413c can be increased. This arrangement is preferable when the reception signal of the third reception winding 413c affects the measurement accuracy.

  Next, planar shapes of the first to third transmission windings 421a to 412c, the first to fourth reception windings 413a to 413d, and the first to fourth magnetic flux coupling bodies 422a, 422b, 512a, and 512b are described. explain.

  FIG. 5 is a plan view showing the first to third transmission windings 412a to 412c and the first and third reception windings 413a and 413c. As shown in FIG. 5, the first to third transmission windings 412 a to 412 c are formed coaxially with the spindle 3 and have a substantially circular current path. The second transmission winding 412b is formed on the outer peripheral side of the first transmission winding 412a, and the third transmission winding 412c is formed on the outer peripheral side of the second transmission winding 412b.

  As shown in FIG. 5, the first and third reception windings 413 a and 413 c are formed coaxially and annularly with respect to the spindle 3. The first reception winding 413a is provided at a position on the outer peripheral side of the first transmission winding 412a and on the inner peripheral side of the second transmission winding 412b. The third reception winding 413c is provided at a position on the outer peripheral side of the second transmission winding 412b and on the inner peripheral side of the third transmission winding 412c. That is, the third reception winding 413c is provided on the outer periphery of the first reception winding 413a. Each of the first and third reception windings 413a and 413c is composed of three reception windings 413aa to 413ac and 413ca to 413cc whose phases are different in the rotation direction. The reception windings 413aa to 413ac and 413ca to 413cc are arranged such that portions intersecting each other are arranged vertically via an insulating layer 411A so that the intersection portions are not short-circuited, and are connected through through holes or via holes, respectively. Insulated and separated.

  Next, the shapes of the reception windings 413aa and 413ca will be described with reference to FIG. FIG. 6 is a plan view showing the reception windings 413aa and 413ca.

  As shown in FIG. 6, the reception winding 413aa has a loop shape (diamond shape) that periodically changes with a pitch λ1 in the rotation direction of the rotors 42 and 51. In the receiving winding 413aa, in the example shown in FIG. 6, ten (N1) diamond-shaped pairs PA1 are provided. The reception windings 413ab and 413ac have the same shape as the reception winding 413aa.

  As shown in FIG. 6, the reception winding 413 ca has a loop shape (diamond shape) that periodically changes with a pitch λ 3 in the rotation direction of the rotors 42 and 51. In the receiving winding 413ca, in the example shown in FIG. 6, ten (N3) diamond-shaped pairs PA3 are provided. The reception windings 413cb and 413cc have the same shape as the reception winding 413ca.

  Next, the shapes of the second and fourth reception windings 413b and 413d will be described with reference to FIG. FIG. 7 is a plan view showing the second and fourth reception windings 413b and 413d.

  As shown in FIG. 7, the second and fourth reception windings 413 b and 413 d are formed coaxially and annularly with respect to the spindle 3. The second reception winding 413b is formed so as to overlap the first reception winding 413a in the stacking direction. The fourth reception winding 413d is located on the outer peripheral side of the third reception winding 413b, and is formed so as to overlap the third reception winding 413c in the stacking direction. The second and fourth reception windings 413b and 413d are respectively configured by three reception windings 413ba to 413bc and 413da to 413dc whose phases are different in the rotation direction. The receiving windings 413ba to 413bc and 413da to 413dc are arranged such that the intersecting portions are arranged vertically via the insulating layer 411C so that the intersecting portions are not short-circuited, and are connected by through holes or via holes, respectively. Insulated and separated.

  Next, the shapes of the reception windings 413ba and 413da will be described with reference to FIG. FIG. 8 is a plan view showing the reception windings 413ba and 413da.

  As shown in FIG. 8, the reception winding 413ba has a loop shape (diamond shape) that periodically changes with a pitch λ2 (λ2 ≠ λ1) different from the pitch λ1 in the rotation direction of the rotors 42 and 51. In the receiving winding 413ba, in the example shown in FIG. 8, nine (N2) diamond-shaped pairs PA2 are provided. In the present embodiment, the pitch λ1 is shorter than the pitch λ2 (λ1 <λ2). The reception windings 413bb and 413bc have the same shape as the reception winding 413ba.

  As shown in FIG. 8, the reception winding 413da has a loop shape (diamond shape) that periodically changes with a pitch λ4 (λ4 ≠ λ3) different from the pitch λ3 in the rotation direction of the rotors 42 and 51. In the receiving winding 413da, in the example shown in FIG. 8, nine (N4) diamond-shaped pairs PA4 are provided. In the present embodiment, the pitch λ3 is shorter than the pitch λ4 (λ3 <λ4). The reception windings 413db and 413dc have the same shape as the reception winding 413da.

  Next, the shape of the first magnetic flux coupling body 422a will be described with reference to FIG. 9A. FIG. 9A is a plan view showing the first magnetic flux coupling body 422a. As shown in FIG. 9A, the first magnetic flux coupling body 422a is formed coaxially with the spindle 3, and is formed so as to overlap the first reception winding 413a via a gap. The first magnetic flux coupling body 422a has a continuous gear-shaped wiring portion that periodically changes in the rotation direction of the rotors 42 and 51 at the same pitch λ1 as the first receiving winding 413a, and the gear-shaped wiring portion. A wiring having a shape overlapping an inscribed circular wiring portion is provided. More specifically, the first magnetic flux coupling body 422a alternately includes concave portions 422aa that are recessed in a direction approaching the spindle 3 and convex portions 422ab that protrude in a direction away from the spindle 3. The first magnetic flux coupling body 422a has an annular coupling portion 422ac that couples the plurality of recesses 422aa. That is, the plurality of concave portions 422aa and the convex portions 422ab form a gear-shaped current path, and the plurality of concave portions 422aa and the connecting portion 422ac form an annular current path. In the example shown in FIG. 9A, ten (N1) combinations PA5 of the concave portion 422aa, the convex portion 422ab, and the connecting portion 422ac are provided.

  Next, the shape of the third magnetic flux coupling body 512a will be described with reference to FIG. 9B. FIG. 9B is a plan view showing the third magnetic flux coupling body 512a. As shown in FIG. 9B, the third magnetic flux coupling body 512a is formed coaxially with the spindle 3, and is formed so as to overlap the third reception winding 413c via a gap. The third magnetic flux coupling body 512a includes a continuous gear-shaped wiring portion that periodically changes in the rotation direction of the rotors 42 and 51 at the same pitch λ3 as the third reception winding 413c, and the gear-shaped wiring portion. A wiring having a shape overlapping an inscribed circular wiring portion is provided. More specifically, the third magnetic flux coupling body 512 a alternately includes concave portions 512 aa that are recessed in a direction approaching the spindle 3 and convex portions 512 ab that protrude in a direction away from the spindle 3. The third magnetic flux coupling body 512a has an annular coupling portion 512ac that couples the plurality of recesses 512aa. That is, the plurality of recesses 512aa and the protrusions 512ab form a gear-shaped current path, and the plurality of recesses 512aa and the connection part 512ac form an annular current path. In the example shown in FIG. 9B, ten (N3) combinations PA6 of the recesses 512aa, the protrusions 512ab, and the connection parts 512ac are provided.

  Next, the shape of the second magnetic flux coupling body 422b will be described with reference to FIG. 10A. FIG. 10A is a plan view showing the second magnetic flux coupling body 422b. As shown in FIG. 10A, the second magnetic flux coupling body 422b is formed coaxially with the spindle 3, and is formed so as to overlap in the stacking direction via the first magnetic flux coupling body 422a and the insulating layer 421A. . The second magnetic flux coupling body 422b includes a continuous gear-shaped wiring portion that periodically changes in the rotation direction of the rotors 42 and 51 with a pitch λ2, and a circular wiring portion that circumscribes the gear-shaped wiring portion. Overlapping shapes are provided. More specifically, the second magnetic flux coupling body 422b alternately includes concave portions 422ba that are recessed in a direction approaching the spindle 3 and convex portions 422bb that protrude in a direction away from the spindle 3. Further, the second magnetic flux coupling body 422b has an annular coupling portion 422bc that couples the plurality of convex portions 422bb. That is, the plurality of convex portions 422bb and the connecting portion 422bc form an annular current path, and the plurality of concave portions 422ba and the convex portion 422bb form a gear-shaped current path. In the example shown in FIG. 10A, nine (N2) combinations PA7 of the concave portion 422ba, the convex portion 422bb, and the connecting portion 422bc are provided.

  Next, the shape of the fourth magnetic flux coupling body 512b will be described with reference to FIG. 10B. FIG. 10B is a plan view showing the fourth magnetic flux coupling body 512b. As shown in FIG. 10B, the fourth magnetic flux coupling body 512b is formed coaxially with the spindle 3, and is formed so as to overlap in the stacking direction via the third magnetic flux coupling body 512a and the insulating layer 511A. . The fourth magnetic flux coupling body 512b includes a continuous gear-shaped wiring portion that periodically changes in the rotation direction of the rotors 42 and 51 with a pitch λ4, and a circular wiring portion that circumscribes the gear-shaped wiring portion. Overlapping shapes are provided. More specifically, the fourth magnetic flux coupling body 512b alternately includes concave portions 512ba that are recessed in a direction approaching the spindle 3 and convex portions 512bb that protrude in a direction away from the spindle 3. The fourth magnetic flux coupling body 512b has an annular coupling portion 512bc that couples the plurality of convex portions 512bb. That is, the plurality of convex portions 512bb and the connecting portion 512bc form an annular current path, and the plurality of concave portions 512ba and the convex portion 512bb form a gear-shaped current path. In the example illustrated in FIG. 10B, nine (N4) combinations PA8 of the recesses 512ba, the protrusions 512bb, and the connection parts 512bc are provided.

  3 to 10B, the first receiving winding 413a and the first magnetic flux coupling body 422a have the first track having a shape that periodically changes in the rotation direction of the rotor 42 with the pitch λ1. Form. This first track generates 10 (N1) periodic changes in one rotation of the rotor 42. The second receiving winding 413b and the second magnetic flux coupling body 422b form a second track having a shape that periodically changes in the rotation direction of the rotor 42 with a pitch λ2 different from the pitch λ1. This second track generates nine (N2) periodic changes in one revolution of the rotor 42. In the present embodiment, the pitch λ1 of the first track is shorter than the pitch λ2 of the second track, and more than the distance between the second reception winding 413b of the second track and the second magnetic flux coupling body 422b. The distance between the first receiving winding 413a of the first track and the first magnetic flux coupling body 422a is short. As a result, the signal intensity of the first track at the pitch λ1 is higher than the signal intensity of the second track, so that high measurement accuracy can be obtained.

  The third reception winding 413c and the third magnetic flux coupling body 512a form a third track having a shape that periodically changes in the rotation direction of the rotor 51 with a pitch λ3. The third track generates 10 (N3) periodic changes in one rotation of the rotor 51. The fourth reception winding 413d and the fourth magnetic flux coupling body 512b form a fourth track having a shape that periodically changes in the rotation direction of the rotor 51 with a pitch λ4 different from the pitch λ3. This fourth track generates nine (N4) periodic changes in one rotation of the rotor 51. In the present embodiment, the pitch λ3 of the third track is shorter than the pitch λ4 of the fourth track, and more than the distance between the fourth receiving winding 413d of the fourth track and the fourth magnetic flux coupling body 512b, The distance between the third receiving winding 413c of the third track and the third magnetic flux coupling body 512a is short. As a result, the signal intensity of the third track with the pitch λ3 is higher than the signal intensity of the fourth track, so that high measurement accuracy can be obtained.

  FIG. 11 shows current supply means for supplying current to the first to third transmission windings 412a to 412c. One end of each of the first to third transmission windings 412a to 412c is grounded, and the other end is connected to the AC power source V via the switch S1. At the time of measurement, a transmission current whose current direction changes periodically is supplied to the first to third transmission windings 412a to 412c by switching the switch S1. Specifically, the transmission current is supplied only to the second transmission winding 412b, and then the transmission current is supplied to only the first and third transmission windings 412a and 412c simultaneously. These steps are repeated.

  Next, signals obtained by the first to fourth reception windings 413a to 413d will be described with reference to FIGS. 12A, 12B, and 13. FIG. As described above, the first to third transmission windings 412a to 412c flow the transmission current whose current direction changes periodically in a time division manner.

  First, with reference to FIG. 12A, a case where a current is passed through the second transmission winding 412b will be described. When a current flows clockwise through the second transmission winding 412b, a magnetic field is generated in the right-handed direction in each current path. This magnetic field is generated by the first to fourth magnetic flux coupling bodies 422a, 422b, 512a, and 512b. The current flows through the first to fourth magnetic flux coupling bodies 422a, 422b, 512a, and 512b counterclockwise.

  In the first magnetic flux coupling body 422a, as shown in FIG. 12A, a large amount of current is mainly induced in the convex portion 422ab. Therefore, the current induced in the first magnetic flux coupling body 422a mainly flows through a gear-shaped current path formed by the concave portion 422aa and the convex portion 422ab. As a result, a magnetic field is generated in the concave portion 422aa of the first magnetic flux coupling body 422a from the front surface to the rear surface in FIG. 12A and from the rear surface to the front surface in the convex portion 422ab. A periodic magnetic pattern is formed. These magnetic fields are received by the first reception winding 413a.

  In the second magnetic flux coupling body 422b, as shown in FIG. 12A, a current is induced in the convex portion 422bb and the connecting portion 422bc, and the current flows mainly through an annular current path. The current flowing through the gear-shaped current path formed by the recesses 422ba and the protrusions 422bb has a value of about one-tenth of the current flowing through the annular current path. Therefore, the magnetic field forming the magnetic pattern having the pitch λ2 generated in the second magnetic flux coupling body 422b is extremely small as compared with the magnetic field forming the magnetic pattern having the pitch λ1 generated in the first magnetic flux coupling body 422a. In addition, the first magnetic flux coupling body 422a has a pitch of λ1 × 10 while the second magnetic flux coupling body 422b has a length of one round of the pitch λ2 × 9. As shown in FIG. 13, the influence of the magnetic field coupled to the first reception winding 413a cancels the influence of the magnetic field from the second magnetic flux coupling body 422b in one round. That is, the induced voltage caused by the second magnetic flux coupling body 422b cancels out in the first reception winding 413a due to the different pitches λ1 and λ2, so that the signal is not detected. The first reception winding 413a can suppress crosstalk from the second magnetic flux coupling body 422b.

  In the third magnetic flux coupling body 512a, as shown in FIG. 12A, a current is induced in the recess 512aa and the connecting portion 512ac, and the current mainly flows through an annular current path. Therefore, as in the case described above, almost no magnetic field is generated from the third magnetic flux coupling body 512a, and even if a slight magnetic field induces a current in the fourth receiving winding 512b, the third magnetic flux coupling body 512a The current cancels out due to the difference in phase between the magnetic flux coupling body 512a and the fourth receiving winding 413d, and is not detected.

  On the other hand, in the fourth magnetic flux coupling body 512b, a large amount of current is induced in the recess 512ba. For this reason, an electric current mainly flows through the gear-shaped current path formed by the concave portion 512ba and the convex portion 512bb. As a result, a magnetic field is generated in the concave portion 512ba of the fourth magnetic flux coupling body 512b from the front surface to the back surface of FIG. 12A, and the convex portion 512bb is generated from the back surface to the front surface of the paper surface. A periodic magnetic pattern is formed. These magnetic fields are received by the fourth reception winding 413d.

  Next, with reference to FIG. 12B, the case where a current is passed through the first and third transmission windings 412a and 412c will be described. When a current flows clockwise through the first and third transmission windings 412a, 412c, the first to fourth magnetic flux coupling bodies 422a, 422b, A current flows counterclockwise through 512a and 512b.

  In the first magnetic flux coupling body 422a, as shown in FIG. 12B, a current is induced in the recess 422aa and the connecting portion 422ac, and the current mainly flows through an annular current path. Therefore, as in the case described above, a magnetic field with a pitch λ1 is hardly generated from the first magnetic flux coupling body 422a, and a magnetic field with a slight pitch λ1 induces a current in the second receiving winding 413b. Even if the induced voltage caused by the first magnetic flux coupling body 422a cancels out in the second receiving winding 413b due to the difference in pitch between the first magnetic flux coupling body 422a and the second receiving winding 413b, It is never detected.

  On the other hand, in the second magnetic flux coupling body 422b, as shown in FIG. 12B, a large amount of current is induced in the recess 422ba. For this reason, an electric current mainly flows through the gear-shaped current path formed from the concave portion 422ba and the convex portion 422bb. As a result, a magnetic field is generated in the concave portion 422ba of the second magnetic flux coupling body 422b from the front surface to the back surface of FIG. 12B, and in the convex portion 422bb, the magnetic field is generated from the back surface to the front surface of the paper surface. A periodic magnetic pattern is formed. These magnetic fields are received by the second reception winding 413b.

  In the third magnetic flux coupling body 512a, a large amount of current is induced in the convex portion 512ab as shown in FIG. 12B. For this reason, an electric current mainly flows through the gear-shaped current path formed from the concave portion 512aa and the convex portion 512ab. As a result, a magnetic field is generated in the concave portion 512aa of the third magnetic flux coupling body 512a from the front surface to the rear surface in FIG. 12B, and the convex portion 512ab is generated from the rear surface to the front surface in the paper surface. A periodic magnetic pattern is formed. These magnetic fields are received by the third reception winding 413c.

  On the other hand, in the fourth magnetic flux coupling body 512b, as shown in FIG. 12B, current is induced in the convex portion 512bb and the connecting portion 512bc, and the current mainly flows through the annular current path. Therefore, as in the case described above, the fourth magnetic flux coupling body 512b generates almost no magnetic field with the pitch λ4, and a slight magnetic field with the pitch λ4 induces a current in the third receiving winding 413c. Even if the induced voltage caused by the third magnetic flux coupling body 512a cancels out in the fourth receiving winding 512b due to the difference in pitch between the third magnetic flux coupling body 512a and the fourth receiving winding 512b, It is never detected.

  As described above, as shown in FIG. 13, reception signals that change in accordance with the positions of the rotors 42 and 51 with respect to the stator 41 are obtained from the first to fourth reception windings 413 a to 413 d. Since the reception signals obtained by the first and second reception windings 413a and 413b are shifted by one turn while the rotor 42 makes one rotation, the absolute position in one rotation is detected from these two reception signals. Can do. Similarly, the reception signals obtained by the third and fourth reception windings 413c and 413d are shifted by one turn while the rotor 51 makes one rotation, so the absolute position in one rotation is determined from these two reception signals. Can be detected. Note that FIG. 13 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 413a and 413b can be stacked in the longitudinal direction of the spindle 3 via the insulating layer, and similarly, the third and fourth receiving windings are arranged. The wires 413c and 413d can be overlapped in the longitudinal direction of the spindle 3 via an insulating layer. The first and second magnetic flux coupling bodies 422a and 422b can also be stacked in the longitudinal direction of the spindle 3 through the insulating layer. Similarly, the third and fourth magnetic flux coupling bodies 512a and 512b also have an insulating layer. And can be stacked in the longitudinal direction of the spindle 3. Therefore, the outer diameter of the encoder can be reduced and the occurrence of crosstalk can be suppressed. Furthermore, since four tracks can be driven by the three transmission windings 412a to 412c, the configuration of the inductive detection type rotary encoder can be further simplified.

  Next, the configuration of the transmission / reception control unit 6 and the arithmetic processing unit 7 will be described in detail with reference to FIG. FIG. 14 is a block diagram illustrating configurations of the transmission / reception control unit 6 and the arithmetic processing unit 7.

  First, the transmission / reception control unit 6 will be described. The transmission / reception control unit 6 includes a transmission control unit 60, a first reception control unit 64, and a second reception control unit 66.

  The transmission control unit 60 controls transmission of signals to the first and second rotary encoders 40 and 50. The transmission control unit 60 transmits a predetermined AC signal for the first and second rotors 42 and 51 (for the first to third transmission windings 412a to 412c) to the stator 41.

  The first reception control unit 64 receives the phase signal of the first rotor 42 from the stator 41 (the first reception winding 413a and the second reception winding 413b). Here, the phase signal is a signal indicating a phase difference between a signal based on the first magnetic flux coupling body 422a and a signal based on the second magnetic flux coupling body 422b.

  The second reception control unit 66 receives the phase signal of the second rotor 51 from the stator 41 (the third reception winding 413c and the fourth reception winding 413d). Here, the phase signal is a signal indicating a phase difference between a signal based on the third magnetic flux coupling body 512a and a signal based on the fourth magnetic flux coupling body 512b. The first reception control unit 64 and the second reception control unit 66 output the phase signals of the rotors 42 and 51 received from the stator 41 to the arithmetic processing unit 7.

  Next, the arithmetic processing unit 7 will be described. The arithmetic processing unit 7 includes a rotation angle calculation unit 71, a rotation phase calculation unit 72, and a spindle position calculation unit 73. The rotation angle calculation unit 71 calculates the rotation angles θ1 and θ2 of the first rotor 42 and the second rotor 51, respectively. The rotation phase calculation unit 72 calculates the rotation phase of the spindle 3 based on the rotation angles θ1 and θ2 of the rotors 42 and 51 calculated by the rotation angle calculation unit 71. The spindle position calculation unit 73 calculates the absolute position of the spindle 3 based on the rotation phase of the spindle 3 calculated by the rotation phase calculation unit 72.

  The rotation angle calculation unit 71 includes a first rotation angle calculation unit 74 and a second rotation angle calculation unit 75. The first rotation angle calculation unit 74 calculates the rotation angle θ1 of the first rotor 42 based on the phase signal from the first reception control unit 64. The second rotation angle calculation unit 75 calculates the rotation angle θ2 of the second rotor 51 based on the phase signal from the second reception control unit 66.

  Based on the phase signal from the first reception control unit 64, the first rotation angle calculation unit 74 sets the rotation angle θ1 of the first rotor 42 as an absolute angle within one rotation (0 ° <θ1 <360 °). calculate. Here, the phase signal from the first reception control unit 64 does not produce the same phase within one rotation of the first rotor 42. In the first rotation angle calculation unit 74, the rotation angle θ1 of the first rotor 42 and the phase signal are set and stored in a one-to-one relationship. Thus, the rotation angle θ1 of the first rotor 42 is uniquely determined according to the phase signal output from the first reception control unit 64, and the absolute angle within one rotation of the first rotor 42 is calculated. The

  Similarly to the first rotation angle calculation unit 74, the second rotation angle calculation unit 75 rotates the rotation angle θ2 of the second rotor 51 by one rotation based on the phase signal from the second reception control unit 66. It is calculated as an absolute angle.

  The rotation phase calculation unit 72 includes a difference calculation unit 76 and a total rotation phase calculation unit 77. The difference calculation unit 76 calculates a difference θ3 between the rotation angles θ1 and θ2 of the rotors 42 and 51 calculated by the rotation angle calculation unit 71. The total rotation phase calculation unit 77 calculates the total rotation phase of the spindle 3 based on the difference θ3.

  In the total rotation phase calculation unit 77, the difference θ3 and the total rotation phase of the spindle 3 are set and stored in a one-to-one relationship. That is, the difference θ3 is set to 0 ° to 360 ° because the difference between the rotation angles θ1 and θ2 of the rotors 42 and 51 is set to one rotation while the spindle 3 rotates 40 times within the range of forward / backward movement. The total rotation phase θT of the spindle 3 is uniquely calculated according to the difference θ3.

  In the spindle position calculation unit 73, a movement pitch (0.5 mm) per rotation of the spindle 3 is set and stored in advance. Then, the spindle position calculation unit 73 multiplies the movement pitch (0.5 mm) and the total rotation phase θT, thereby calculating the total movement amount of the spindle 3, that is, the absolute position of the spindle 3. The display unit 8 displays the absolute position of the spindle 3 by digital display, for example.

  Next, the mechanical operation of this embodiment will be described. When the spindle 3 is rotated by the knob portion 32, the spindle 3 is advanced and retracted in the axial direction by screwing between the female screw 26 of the main body 2 and the feed screw 33 of the spindle 3. When the spindle 3 rotates, the first rotating cylinder 43 rotates with the spindle 3 by the key 47 engaged with the key groove 34 of the spindle 3.

  When the first rotating cylinder 43 rotates, the first rotor 42 rotates together with the first rotating cylinder 43. The rotation of the first rotor 42 is detected by the stator 41 and sent to the first reception control unit 64. Subsequently, the first rotation angle calculation unit 74 calculates the rotation angle θ1 within one rotation of the first rotor 42.

  Here, since the first rotor 42 rotates in synchronization with the spindle 3, the rotation angle θ 1 within one rotation of the first rotor 42 indicates the rotation angle within one rotation of the spindle 3.

  When the first rotating cylinder 43 rotates, the first relay gear 53A of the relay gear 53 that meshes with the gear 48 of the first rotating cylinder 43 rotates. Further, the gear 55 of the second rotating cylinder 52 meshed with the second relay gear 53 B of the relay gear 53 rotates, and the second rotor 51 rotates together with the second rotating cylinder 52. A phase signal within one rotation of the second rotor 51 is detected by the stator 41 and sent to the second reception control unit 66. Subsequently, the second rotation angle calculation unit 75 calculates the rotation angle θ2 within one rotation of the second rotor 51.

  Subsequently, the rotation phase calculation unit 72 calculates the difference θ3 between the rotation angles θ1 and θ2 of the rotors 42 and 51, and the total rotation phase θT of the spindle 3 is calculated based on the difference θ3. Finally, the spindle position calculation unit 73 calculates the absolute position of the spindle 3 based on the total rotational phase θT and the feed pitch (0.5 mm) of the spindle 3 and displays it on the display unit 8.

[Second Embodiment]
Next, the overall configuration of the micrometer head 1a equipped with the inductive detection type rotary encoder 4a according to the second embodiment will be described with reference to FIG. FIG. 15 is a cross-sectional view showing a micrometer head 1a according to the second embodiment. Note that in the second embodiment, identical symbols are assigned to configurations similar to those in the first embodiment and descriptions thereof are omitted.

  As shown in FIG. 15, the micrometer head 1a includes a spindle 3a different from the first embodiment, and an inductive detection type rotary encoder 4a provided around the spindle 3a. The micrometer head 1a has the same configuration as that of the first embodiment.

  As in the first embodiment, the spindle 3a is formed in a substantially cylindrical shape, has a contact surface 31 with an object to be measured (not shown) at the end on the distal end side, and has an end on the proximal end side. A knob portion 32 is provided.

  Unlike the first embodiment, two key grooves 34a and 34b having different lead angles are provided at the center of the spindle 3a. The first keyway 34a is provided in a straight line parallel to the axis of the spindle 3a. The second key groove 34b is provided spirally with respect to the spindle 3a. The positions of the start point and the end point of the first key groove 34a and the second key groove 34b are substantially the same in the axial direction of the spindle 3a. That is, the first key groove 34a and the second key groove 34b are formed in substantially the same range in the axial direction of the spindle 3a.

  When the spindle 3a moves back and forth, the key grooves 34a and 34b come out of the main body 2 together with the spindle 3a, but the key grooves 34a and 34b are exposed to the outside even when the spindle 3a moves forward to the maximum. An outer frame 11 is provided so as not to cause a failure.

  Next, the induction detection type rotary encoder 4a will be described. FIG. 16 is an exploded perspective view of the inductive detection type rotary encoder 4a. As shown in FIG. 16, the inductive detection type rotary encoder 4 a includes a first rotary encoder 40 a and a second rotary encoder 50 a, and is disposed in the storage space 22 of the main body 2.

  The first rotary encoder 40a includes a stator 41a and a first rotor 42a that has a key 47a that engages with the key groove 34a and is provided to be rotatable about the spindle 3a.

  The stator 41a is fixed to the front end side inner wall 28 of the storage space 22 in a state where the spindle 3a is inserted.

  The first rotor 42a is disposed just outside the spindle 3a. The first rotor 42a is disposed at a position separated from the stator 41a by a predetermined distance so as to face the stator 41a in the axial direction. The first rotor 42a supports the rotation of the first rotor plate 48a that rotates in a state of being opposed to the stator 41a as a pair with the stator 41a, and the first rotor plate 48a around the spindle 3a. 1 rotating cylinder 43a and a first key 47a engaged with the first key groove 34a. The first rotor plate 48a is a small disk having a hole through which the spindle 3a is inserted.

  The first rotating cylinder 43a has a cylindrical shape that is fitted on the spindle 3a, is connected to the back surface of the first rotor plate 48a, and supports the rotation of the first rotor plate 48a. The first rotating cylinder 43a is provided with two holes 43aa and 43ab penetratingly formed in a direction orthogonal to the axis, and a first key 47a is screwed into the first hole 43aa. The second hole 43ab is formed in a long hole shape having a length in the circumferential direction of the first rotating cylinder 43a.

  The second rotary encoder 50a includes a stator 41a and a second rotor 51a that has a key 47b that engages with the key groove 34b and is provided to be rotatable about the spindle 3a.

  The second rotor 51a is arranged outside the first rotor 42a so as to surround it. The second rotor 51a is disposed at a position separated from the stator 41a by a predetermined distance so as to face the stator 41a in the axial direction. Similarly to the first rotor 42a, the second rotor 51a is paired with the stator 41a and rotated in a state of facing the stator 41a, and a second rotor plate 55a centered on the spindle 3a. A second rotating cylinder 52a that supports the rotation of the rotor plate 55a and a second key 47b that engages with the second key groove 34b are provided.

  The second rotor plate 55a is an annular plate having an inner hole enough to loosely fit the first rotor plate 48a inside. The second rotating cylinder 52a is connected to the back surface of the second rotor plate 55a, and has a cylindrical shape having a hole in which the first rotating cylinder 43a is loosely fitted.

  The second rotating cylinder 52a has a hole 52aa formed through from a direction orthogonal to the axis, and the second key 47b is screwed into the hole 52aa. The second key 47b is engaged with the second key groove 34b through the second hole 43ab which is a long hole of the first rotating cylinder 43a.

  The second rotating cylinder 52a has a bearing portion 52ab for bearing the spindle 3a on the opposite side of the stator 41a with the first rotor 42a interposed therebetween. In the spindle axis direction, the position of the second key 47b is substantially the same as the position of the first key 47a provided on the first rotating cylinder 43a.

  A spindle bearing 27a extends slightly toward the rear end side of the stator 41a on the front end side inner wall 28 of the storage space 22 to which the stator 41a is fixed. A spindle bearing 43ac of the first rotating cylinder 43a is slightly extended from the first rotor plate 48a toward the stator 41a. When the spindle bearing 43ac of the first rotating cylinder 43a abuts on the spindle bearing 27a of the main body 2, a gap between the stator 41a and the first rotor plate 48a is appropriately secured.

  In addition, a coil spring (biasing means) (not shown) is interposed between the second rotating cylinder 52a and the partition plate 23, and the second rotor 51a is biased toward the stator 41a side. The first rotor 42a is also urged toward the stator 41a by pressing one rotor 42a on the inner wall of the second rotating cylinder 52a.

  Next, the operation of the micrometer head 1a according to the second embodiment having such a configuration will be described. When the spindle 3a is rotated by the knob portion 32, the spindle 3a is advanced and retracted in the axial direction by screwing between the female screw 26 of the main body 2 and the feed screw 33 of the spindle 3a.

  When the spindle 3a is rotated, the first key 47a of the first rotating cylinder 43a and the second key of the second rotating cylinder 52a are inserted into the first key groove 34a and the second key groove 34b of the spindle 3a. Since the keys 47b are respectively engaged, the first rotating cylinder 43a and the second rotating cylinder 52a are rotated with the rotation of the spindle 3a. At this time, since the first rotating cylinder 43a supports the spindle 3a by the spindle bearing 43ac, the first rotating cylinder 43a rotates with reference to the spindle 3a. Further, since the second rotating cylinder 52a supports the spindle 3a by the bearing portion 622, the second rotating cylinder 52a also rotates on the basis of the spindle 3a.

  Since the first key groove 34a and the second key groove 34b have different lead angles, the first rotating cylinder 43a and the second rotating cylinder 52a differ from each other when the spindle 3a rotates once. It is rotated by a rotation amount (rotation phase). When the first and second rotating cylinders 43a and 52a are rotated by the rotation of the spindle 3a, the first rotor plate 48a is rotated together with the first rotating cylinder 43a, and the second rotor together with the second rotating cylinder 52a. The plate 55a is rotated. That is, also in the second embodiment, as in the first embodiment, the first rotor 42a rotates at a rotational speed different from that of the second rotor 51a.

  In the second embodiment, as in the first embodiment, the first and second magnetic flux coupling bodies 422a and 422b are formed on the first rotor 42a facing the stator 41. (Not shown). Third and fourth magnetic flux coupling bodies 512a and 512b are formed on the second rotor 51a facing the stator 41 (not shown). First to third transmission windings 412a to 412c and first to fourth reception windings 412a to 412d are formed on the stator 41a facing the first and second rotors 42a and 51a. (Not shown).

  Since the micrometer head 1a according to the second embodiment is configured in substantially the same manner as the first embodiment, the same effects as those of the first embodiment can be obtained.

[Third Embodiment]
Next, an inductive detection type rotary encoder according to a third embodiment will be described. Note that in the third embodiment, identical symbols are assigned to configurations similar to those in the first embodiment and descriptions thereof are omitted.

  FIG. 17 is a diagram showing current supply means for supplying current to the first to third transmission windings 412a to 412c according to the third embodiment. As shown in FIG. 17, in the third embodiment, transmission currents are separately supplied to the first to third transmission windings 412a to 413c via the switch S1. In this respect, the first embodiment and the third embodiment in which the transmission current is simultaneously supplied to the first and third transmission windings 412a and 412c are different.

  Next, the configuration of the transmission / reception control unit 6 according to the third embodiment will be described with reference to FIG. FIG. 18 is a block diagram illustrating configurations of the transmission / reception control unit 6 and the arithmetic processing unit 7 according to the third embodiment.

  As shown in FIG. 18, the transmission / reception control unit 6 controls the transmission / reception of signals to / from the first rotary encoder 40 and the second transmission / reception control unit 61 to control transmission / reception of signals to / from the second rotary encoder 50. The transmission / reception control unit 62 is provided.

  The first transmission / reception control unit 61 includes a first transmission control unit 63 and a first reception control unit 64. The first transmission control unit 63 transmits a predetermined AC signal for the first rotor 42 (for the first and second transmission windings 412a and 412b) to the stator 41.

  The second transmission / reception control unit 62 includes a second transmission control unit 65 and a second reception control unit 66. The second transmission control unit 65 transmits a predetermined AC signal for the second rotor 51 (for the second and third transmission windings 412b and 412c) to the stator 41.

  Even the third embodiment has the same effect as the first embodiment.

[Other embodiments]
As described above, one embodiment of the inductive detection type rotary encoder according to the present invention has been described. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. , Addition, replacement, etc. are possible. For example, the first to fourth magnetic flux coupling bodies may be electrodes, holes formed in the conductive plate, recesses, or the like.

  In the above-described embodiment, the number of rotations of the first rotor 42 is detected based on the positional relationship between the first rotor 42 and the second rotor 51. However, the present invention may detect how many rotations the second rotor 51 is based on the positional relationship between the first rotor 42 and the second rotor 51.

  In the above embodiment, N1 = N3, N2 = N4, and N4-N3 = N2-N1 = 1, but N1 ≠ N3, N2 ≠ N4, and N4-N3 ≠ N2-N1 ≠ 1. Or N1 = N4 and N2 = N3. Alternatively, N1, N2, N3, and N4 may all be different.

  For example, the second reception winding 413b is opposed to the second magnetic flux coupling body 422b, and the second reception winding 413b and the second magnetic flux coupling body 422a are interposed between the first reception winding 413a and the first magnetic flux coupling body 422a. Two magnetic flux coupling bodies 422b may be arranged. Similarly, the fourth receiving winding 413d faces the fourth magnetic flux coupling body 512b, and the fourth receiving winding 413d and the third magnetic flux coupling body 512a are interposed between the fourth receiving winding 413d and the third magnetic flux coupling body 512a. A fourth magnetic flux coupling body 512b may be arranged.

  The second reception winding 413b faces the first magnetic flux coupling body 422a, and the second reception winding 413b and the second magnetic flux coupling body 422b are interposed between the first reception winding 413a and the second magnetic flux coupling body 422b. One magnetic flux coupling body 422a may be arranged. Similarly, the fourth reception winding 413d faces the third magnetic flux coupling body 512a, and the fourth reception winding 413d and the fourth magnetic flux coupling body 512b are interposed between the third reception winding 413d and the fourth magnetic flux coupling body 512b. A third magnetic flux coupling body 512a may be arranged.

  The first reception winding 413a is opposed to the second magnetic flux coupling body 422b, and the first reception winding 413a and the first magnetic flux coupling body 422a are interposed between the first reception winding 413a and the first magnetic flux coupling body 422a. Two magnetic flux coupling bodies 422b may be arranged. Similarly, the third reception winding 413c faces the fourth magnetic flux coupling body 512b, and the third reception winding 413c and the third magnetic flux coupling body 512a are interposed between the fourth reception winding 413c and the third magnetic flux coupling body 512a. A fourth magnetic flux coupling body 512b may be arranged.

  For example, although the above embodiment is an electromagnetic induction type rotary encoder, the present invention is also applicable to a capacitance type or photoelectric type rotary encoder.

  DESCRIPTION OF SYMBOLS 1,1a ... Micrometer head, 2 ... Main body, 3, 3a ... Spindle, 4, 4a ... Inductive detection type rotary encoder, 40 ... 1st rotary encoder, 50 ... 2nd rotary encoder, 7 ... Arithmetic processing part, 41, 41a ... stator, 42, 42a ... first rotor, 51, 51a ... second rotor, 43 ... first rotating cylinder, 48 ... first gear, 52 ... second rotating cylinder, 53 ... relay Gears, 53A ... first relay gear, 53B ... second relay gear, 53C ... shaft portion of relay gear, 55 ... second gear, 412a to 412c ... first to third transmission windings, 413a to 413d ... 1st-4th receiving winding, 422a, 422b ... 1st, 2nd magnetic flux coupling body, 512a, 512b ... 3rd, 4th magnetic flux coupling body.

Claims (7)

A stator,
A first rotor engaged with a rotating shaft and rotating together with the rotating shaft and facing the stator in the axial direction;
A second rotor disposed on an outer peripheral side of the first rotor and rotatable with respect to the first rotor and opposed to the stator in the axial direction;
Rotation transmitting means for transmitting rotation of the rotating shaft to rotate the second rotor at a speed different from that of the first rotor;
First, second and third transmission windings provided in order from the inner peripheral side to the outer peripheral side of the stator and formed in an annular shape around the rotation axis;
A first portion provided between the first and second transmission windings of the stator, formed in an annular shape around the rotation axis along the first and second transmission windings, and overlapping in the axial direction. A receiving winding and a second receiving winding;
A third portion provided between the second and third transmission windings of the stator, formed in an annular shape around the rotation axis along the second and third transmission windings, and overlapping in the axial direction. A receiving winding and a fourth receiving winding;
First and second magnetic flux coupling bodies provided in the first rotor, formed in an annular shape around the rotation axis, and overlapping the first and second receiving windings in the axial direction;
Third and fourth magnetic flux coupling bodies provided in the second rotor, formed in an annular shape around the rotation axis, and overlapping the third and fourth reception windings in the axial direction;
Current supply means for supplying current to the first, second and third transmission windings in a time-sharing manner;
With
The first receiving winding and the first magnetic flux coupling body have a shape that periodically changes N1 times in one rotation in the rotation direction of the first rotor,
The second receiving winding and the second magnetic flux coupling body have a shape that periodically changes N2 times in one rotation in the rotation direction of the first rotor,
The third reception winding and the third magnetic flux coupling body have a shape that periodically changes N3 times in one rotation in the rotation direction of the second rotor,
The fourth reception winding and the fourth magnetic flux coupling body have a shape that periodically changes N4 times in one rotation in the rotation direction of the second rotor,
N1 is different from N2, N3 is Unlike N4,
When a current is supplied to the first transmission winding by the current supply means, a signal is received by the second reception winding,
When a current is supplied to the second transmission winding by the current supply means, a signal is received by the first and fourth reception windings,
An inductive detection type rotary encoder, wherein when the current is supplied to the third transmission winding by the current supply means, a signal is received by the third reception winding .   N3 is greater than N4
  The inductive detection type rotary encoder according to claim 1.   The third receiving winding faces the third magnetic flux coupling body;
  The third receiving winding and the third magnetic flux coupling body are disposed between the fourth receiving winding and the fourth magnetic flux coupling body.
  The inductive detection type rotary encoder according to claim 2. N1, N2, N3, N4 is inductive detection type rotary encoder according to claim 1 to claim 3, wherein different from each other. Difference N1 and N2 is "1", N3 a difference of N4 is inductive detection type rotary encoder according to claim 1 to claim 4, wherein the is "1". N1 = N3 and N2 = N4. The inductive detection type rotary encoder according to claim 1, 2, 3 or 5 . It said first magnetic flux coupling body has a first current path toothed to have a first N1 times periodically varying shape 1 rotates in the rotational direction of the rotor, of said first current path An annular second current path connecting the peripheral sides,
The second magnetic flux coupling body has an annular third current path and an outer peripheral side connected by the third current path, and has a shape that periodically changes N2 times in one rotation in the rotation direction of the first rotor. to have a and a fourth current path toothed,
It said third flux coupling body includes a fifth current path toothed to have a second N3 times periodically varying shape 1 rotates in the rotational direction of the rotor, of the fifth current path An annular sixth current path connecting the peripheral sides;
The fourth magnetic flux coupling body has an annular seventh current path and an outer peripheral side connected by the seventh current path , and a shape that periodically changes N4 times in one rotation in the rotation direction of the second rotor. inductive detection type rotary encoder according to claim 1 to claim 6, wherein further comprising an eighth current path toothed to have a.

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