JP2014169899A - Position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive position sensor that imparts an offset effect to an output waveform to be obtained by a detection coil with a simple method.SOLUTION: In a rotary encoder 8 including a stator 9 having a planar excitation coil 30 and a detection coil 20 laminated and disposed and a rotor 10 disposed to face the stator 9, in which the excitation coil 30 includes a first excitation coil pattern 30A and a second excitation coil pattern 30B that are wound and arranged so that an excitation current flows in a mutually inverse direction, the detection coil 20 includes a first detection coil 21 to be arranged so as to be interposed in a movement direction of the rotor 10 by the first excitation coil pattern 30A and the second excitation coil pattern 30B, and an output of the first detection coil 21 varies accompanied by a movement of the rotor 10, a first coupling part 40A in which a first connection line 21A connecting the first detection coil 21 and a first output terminal 22A, and the first excitation coil pattern 30A run side by side is provided.

Description

  The present invention is used to detect an operating position of a mover, and is provided with a stator on which a stator coil is formed, and a movable provided so as to be able to operate while facing the stator through a gap. And a position sensor having a child.

  Conventionally, as a technique related to the position sensor, for example, a rotation angle sensor widely used in each field can be cited. 2. Description of the Related Art A rotary encoder that detects a crank angle, which is one of rotation angle sensors, is employed in an engine mounted on an automobile in order to detect its rotation speed and rotation phase.

  Patent Document 1 discloses a technique related to a position detection sensor of a linear pulse motor. An excitation coil and a detection coil are arranged on the mover so as to detect a positional variation with respect to a stator formed of a comb-like magnetic body. This is a position sensor that detects the position of the mover by fluctuation in output from the detection coil.

  Patent Document 2 discloses a technique related to a resolver. This is a phase difference type resolver, which has an excitation coil to which an excitation signal is input and a detection coil to be detected by a detection signal, and is based on a detection signal that is displaced according to the displacement amount of a passive body provided with the excitation coil or the detection coil. A resolver that detects the amount of displacement employs a method in which a detection signal is obtained by demodulating a modulation signal obtained by modulating a high-frequency signal with an excitation signal in an excitation coil.

JP-A-61-226613 JP 2000-292205 A

  However, when the technique of Patent Document 1 or Patent Document 2 is applied to a position sensor, the following problems can be considered.

  Although position sensors are used in various fields, there are many cases where downsizing and high accuracy are desired, such as in-vehicle use. In order to reduce the size, it is conceivable to use a technique used in a resolver as disclosed in Patent Document 2. However, in any of the techniques disclosed in Patent Document 1 and Patent Document 2, in order to increase the position accuracy, it is necessary to increase the placement accuracy of the excitation coil and the detection coil and the pitch accuracy of the magnetic material. However, in order to increase the manufacturing accuracy of a stator including an excitation coil and a detection coil and a rotor having a pattern to be detected, costs are required.

  Accordingly, an object of the present invention is to provide a position sensor capable of increasing detection accuracy in order to solve such a problem.

  In order to achieve the above object, the position sensor according to the present invention has the following characteristics.

(1) A stator having four detection coils and three exciting coils formed in a planar shape, and a rotor having two rows of rotor patterns in which portions having different magnetic properties are alternately arranged along the moving direction. In the position sensors arranged so as to face each other, the four detection coils (first detection coil, second detection coil, third detection coil, and fourth detection coil) move in the moving direction of the rotor with respect to the rotor pattern. The first detection coil and the second detection coil are arranged side by side. Similarly, the third detection coil and the fourth detection coil are arranged side by side, and the first detection coil and the third detection coil are arranged side by side. The detection coils are arranged in a direction perpendicular to the moving direction of the rotor with respect to the rotor pattern, and the three excitation coils (first excitation coil, second excitation coil, and third excitation coil) are arranged. ) Are connected in series, and the first exciting coil, the second exciting coil, and the third exciting coil are arranged in this order in the moving direction of the rotor such that the winding directions of the adjacent exciting coils are different from each other. The right side of one excitation coil is along the left side of the first detection coil and the third detection coil, and the left side of the second excitation coil is along the right side of the first detection coil and the third detection coil. The right side of the coil is disposed along the left side of the second detection coil and the fourth detection coil, and the left side of the third excitation coil is disposed along the right side of the second detection coil and the fourth detection coil. The three detection coils and the fourth detection coil are arranged such that the phases thereof are shifted from each other by a quarter of the period in the rotor pattern.

  According to the aspect described in (1) above, the position sensor can be highly accurate. The first detection coil to the fourth detection coil are arranged so that electromotive forces are generated in opposite directions on the left side and the right side, and the first detection coil, the third detection coil, the second detection coil, The fourth detection coils are arranged in a direction orthogonal to the traveling direction of the rotor. For this reason, it becomes difficult to produce each shift | offset | difference of the 1st detection coil and 3rd detection coil used as the object which takes a differential, and a 2nd detection coil and a 4th detection coil. This is because gap deviation caused by the assembly accuracy of the rotor is less likely to occur. As a result, the amplitude ratio of the signal obtained by the detection coil can be increased without increasing the excitation signal output to the excitation coil. As a result, the detection accuracy of the position sensor can be increased.

(2) In the position sensor according to (1), the rotor pattern is configured in two rows of a first rotor pattern and a second rotor pattern, and portions having different magnetic characteristics are arranged in a staggered manner in the moving direction of the rotor. As described above, the second rotor pattern is shifted from the first rotor pattern, and the first detection coil, the third detection coil, the second detection coil, and the fourth detection coil are: Arranged in a direction orthogonal to the moving direction of the rotor, A phase signals are generated from the first detection coil and the third detection coil, and B phase signals are generated from the second detection coil and the fourth detection coil. Forming.

  According to the aspect described in (2) above, an A-phase signal is generated from the first detection coil and the third detection coil of the stator, and a B-phase signal is output from the second detection coil and the fourth detection coil. Accordingly, since the A phase signal and the B phase signal are output using the same set of exciting coils, they are similarly affected by the magnetic flux generated at portions other than the adjacently arranged exciting coils. For this reason, it is possible to cancel the influence of the magnetic flux, and as a result, it is possible to improve the accuracy of the angle sensor.

(3) In the position sensor according to (1) or (2), the side of the excitation coil on the side where the lead-out line connected to the excitation coil or the detection coil and the excitation coil are arranged close to each other Is arranged on the side of the stator facing the rotor so as to be covered with a shield pattern made of a nonmagnetic conductor.

  In the above (3), according to the aspect described above, it is possible to prevent the detection coil lead-out line from picking up a change in magnetic flux generated with the movement of the rotor by the shield pattern arranged on the stator. As a result, noise mixed with the output of the position sensor can be reduced.

(4) In the position sensor according to any one of (1) to (3), the excitation coil, the detection coil, and a lead wire connected to the excitation coil or the detection coil are stacked and formed. The lead wire connected to the exciting coil is arranged so as to be sandwiched between shield patterns made of a nonmagnetic conductor.

  According to the aspect described in (4) above, generation of unnecessary magnetic flux in the coil portion that does not contribute to position detection can be reduced. Although the lead wire connected to the detection coil does not contribute to position detection, noise may be mixed in the output due to the influence of magnetic flux. However, the noise mixed in the output of the position sensor can be reduced by sandwiching the shield pattern.

(5) In the position sensor according to any one of (1) to (4), the excitation coil and the extraction line of the detection coil have a portion formed in a separate layer, and at least a part thereof A shield pattern made of a non-magnetic conductor corresponding to is disposed between the layers.

  According to the aspect described in (5) above, unnecessary coupling between the detection coil and the excitation coil can be prevented and there is an effect of reducing crosstalk, so that it is possible to reduce noise mixed with the output of the position sensor.

(6) In the position sensor according to any one of (1) to (5), the take-out line connected to the excitation coil or the detection coil includes the excitation coil or the detection coil and the rotor pattern. It arrange | positions in the surface different from the opposing opposing surface, It is characterized by the above-mentioned.

  According to the aspect described in (6) above, it is difficult to be affected by the inductance change accompanying the movement of the rotor, and noise can be reduced.

It is a perspective view which shows the outline of the rotary encoder of 1st Embodiment. It is a top view showing the pattern provided in a stator of 1st Embodiment. It is a schematic diagram which shows the rotary encoder of 1st Embodiment. It is a detection block diagram of a rotary encoder of a 1st embodiment. It is the schematic diagram of the rotary encoder prepared for the comparison. It is a schematic diagram which shows the structure of the rotary encoder of 2nd Embodiment. It is typical which shows the structure of the rotary encoder of 3rd Embodiment. It is a top view which shows the wiring pattern provided in a stator of 4th Embodiment. It is a schematic cross section of the rotary encoder of 4th Embodiment. It is a top view which shows the surface of the wiring pattern provided in a stator of 5th Embodiment. It is a top view which shows the back surface of the wiring pattern provided in a stator of 5th Embodiment. It is a schematic cross section of the rotary encoder of 5th Embodiment. It is a top view which shows the 2nd layer of the wiring pattern provided in a stator of 6th Embodiment. It is a top view which shows the 3rd layer of the wiring pattern provided in a stator of 6th Embodiment. It is a schematic cross section of the rotary encoder of 6th Embodiment. It is the top view which performed the permeation | transmission process of the rotary encoder of 7th Embodiment. It is a right view of the rotary encoder of 7th Embodiment. It is a left view of the rotary encoder of 7th Embodiment. It is a top view of the rotary encoder of 7th Embodiment.

  Next, a first embodiment of the present invention will be described with reference to the drawings using a specific example used for a rotary encoder for detecting a rotation angle prepared for a crankshaft of an automobile.

  FIG. 1 is a perspective view schematically showing a rotary encoder 8 according to the first embodiment. A rotary encoder 8 as a kind of position sensor includes a rotor 10 corresponding to a mover attached to a rotating shaft (not shown) and a stator 9 corresponding to a stator fixed to a part of the outer periphery of the rotor 10. Since the rotor 10 is preferably made of a nonmagnetic conductive metal, the first embodiment uses a cylindrical body having an outer diameter of 80 mm and a width of 10 mm using nonmagnetic stainless steel. As long as the material is non-magnetic and conductive metal, for example, aluminum can be used in addition to stainless steel.

  In FIG. 2, the top view showing the wiring pattern 50 provided in the stator 9 is shown. FIG. 3 shows a schematic diagram of the rotary encoder 8. The wiring pattern 50 provided on the stator 9 includes the detection coil 20 and the excitation coil 30 and is formed so as to be overlapped. Four detection coils 20 and three excitation coils 30 are provided. The detection coil 20 includes a first detection coil 21, a second detection coil 22, a third detection coil 23, and a fourth detection coil 24. On the other hand, the excitation coil 30 includes a first excitation coil 31, a second excitation coil 32, and a third excitation coil 33.

  The left sides of the first detection coil 21 and the third detection coil 23 are formed along the right side of the first excitation coil 31, and the right sides of the first detection coil 21 and the third detection coil 23 are the second excitation coil 32. It is formed along the left side. The right side of the second excitation coil 32 is formed along the left side of the second detection coil 22 and the fourth detection coil 24, and the right side of the second detection coil 22 and the fourth detection coil 24 is the third excitation coil. It is formed along the left side of 33. Further, the first detection coil 21 and the second detection coil 22 are arranged so as to be shifted so that the phase is advanced by 90 degrees in terms of electrical angle.

  As shown in FIG. 1, two rotor patterns 13 are prepared concentrically on the side surface of the rotor 10, and are provided with an outer peripheral pattern 13A and an inner peripheral pattern 13B. However, in FIG. 3, they are arranged in parallel for convenience of explanation. The outer peripheral pattern 13A and the inner peripheral pattern 13B are formed so that the magnetic body portions 11 and the nonmagnetic body portions 12 are alternately arranged. The magnetic body portion 11 is formed of a resin binder on a magnetic powder using ferrite or the like. The mixture is applied to the end face of the rotor 10 by screen printing. The nonmagnetic body portion 12 is a bare metal portion of the rotor 10 to which the magnetic body portion 11 is not applied. The magnetic body portions 11 and the nonmagnetic body portions 12 are alternately arranged, and the magnetic body portions 11 and the nonmagnetic body portions 12 are arranged. The width is set to advance by 180 ° in electrical angle. Further, the outer peripheral pattern 13A and the inner peripheral pattern 13B have a positional relationship such that the magnetic body portions 11 are arranged in a staggered manner as shown in FIG.

  FIG. 4 shows a detection block diagram of the rotary encoder 8. A high-frequency sine wave of about 2 MHz is input to the exciting coil 30. As a result, the number of windings of the exciting coil 30 can be reduced. The terminal of the first detection coil 21 is connected to the amplifier 51 and inputs the signal S1 to the amplifier 51. The amplifier 51 amplifies the signal S1 to obtain a signal S5. The third detection coil 23 is connected to the amplifier 52 and inputs the signal S2 to the amplifier 52. The second detection coil 22 is connected to the amplifier 53 and inputs the signal S3 to the amplifier 53. The fourth detection coil 24 is connected to the amplifier 54 and inputs the signal S4 to the amplifier 54.

  Next, the envelope detection of the outer envelope of the high frequency signal S5 obtained from the amplifier 51 is performed by the envelope detector 61 to obtain a signal S8. Similarly, a high frequency signal S6 obtained from the amplifier 52, a high frequency signal S7 obtained from the amplifier 53, and a high frequency signal S8 obtained from the amplifier 54 are respectively an envelope detector 62, an envelope detector 63, and an envelope. The signal S10, the signal S11, and the signal S12 are input to the detector 64. The signal S10 is 180 ° out of phase with the signal S9, the signal S11 is 90 ° out of phase, and the signal S12 is 270 ° out of phase. This is because the first detection coil 21 to the fourth detection coil 24 are arranged as shown in FIG.

  The output waveform S9 of the envelope detector 61 and the output waveform S10 of the envelope detector 62 are input to the differential amplifier 55, and both are differentially amplified to obtain a signal S13. The signal S13 is input to the comparator 65 to obtain a pulse signal S15. The output waveform S11 of the envelope detector 63 and the output waveform S12 of the envelope detector 64 are input to the differential amplifier 56, and both are differentially amplified to obtain a signal S14. The signal S14 is input to the comparator 66 to obtain the pulse signal S16. The rotation angle of the rotor 10 with respect to the stator 9 can be calculated using the pulse signal S15 and the pulse signal S16.

  Since the rotary encoder 8 which is the position sensor of the first embodiment has the above-described configuration, the following operations and effects are achieved.

  First, according to the aspect of the first embodiment, it is possible to increase the accuracy of the rotary encoder 8 that is a position sensor. This includes a stator having four detection coils 20 and three excitation coils 30 formed in a planar shape, and two rows of rotor patterns 13 in which portions having different magnetic properties are alternately arranged along the moving direction. In the rotary encoder 8 arranged so as to face the rotor 10, the four detection coils 20 (first detection coil 21, second detection coil 22, third detection coil 23, and fourth detection coil 24) are rotor patterns. 13, the first detection coil 21 and the second detection coil 22 are arranged side by side in the moving direction of the rotor 10. Similarly, the third detection coil 23 and the fourth detection coil 24 are arranged side by side. ing. The first detection coil 21 and the third detection coil 23 are arranged in a direction perpendicular to the moving direction of the rotor 10 with respect to the rotor pattern 13.

  The three excitation coils 30 (the first excitation coil 31, the second excitation coil 32, and the third excitation coil 33) are connected in series, and the first excitation coil 31, the second excitation coil 32, and the second excitation coil 31 are connected in the moving direction of the rotor 10. In order of the three excitation coils 33, the winding directions of the adjacent excitation coils are arranged differently. The right side of the first excitation coil 31 is along the left side of the first detection coil 21 and the third detection coil 23, and the left side of the second excitation coil 32 is along the right side of the first detection coil 21 and the third detection coil 23. The right side of the second excitation coil 32 is arranged along the left side of the second detection coil 22 and the fourth detection coil 24, and the left side of the third excitation coil 33 is arranged along the right side of the second detection coil 22 and the fourth detection coil 24. Has been.

  And the 3rd detection coil 23 and the 4th detection coil 24 are arrange | positioned at the rotor pattern 13 so that a phase may shift | deviate by 1/4 (90 degree | times) with respect to a period. As a result, in the first detection coil 21 to the fourth detection coil 24 shown in FIG. 3, an electromotive force is generated in which the right side and the left side are opposite to each other. At this time, since the positions of the magnetic body portions 11 are different by 180 degrees between the outer peripheral pattern 13A and the inner peripheral pattern 13B, different outputs are obtained between the first detection coil 21 and the third detection coil 23. Also, different outputs can be obtained by the second detection coil 22 and the fourth detection coil 24. By taking this output differential, the pulse signal S15 and the pulse signal S16 shown in FIG. 4 are obtained, and the angle of the rotary encoder 8 can be detected.

  FIG. 5 shows a schematic diagram of the rotary encoder 108 prepared for comparison. FIG. 4 is a diagram corresponding to FIG. 3. The rotary encoder 108 includes a rotor 110 and a stator 109. On the rotary encoder 108, the magnetic body parts 11 are arranged at equal intervals so that the magnetic body parts 11 and the non-magnetic body parts 12 are alternately arranged. In the stator 109, five exciting coils 30 are arranged, and a first detection coil 21, a second detection coil 22, a third detection coil 23, and a fourth detection coil 24 are arranged therebetween. The second detection coil 22 is advanced by 90 degrees with respect to the first detection coil 21. The third detection coil 23 and the fourth detection coil 24 are similarly arranged.

  Since the rotary encoder 108 having such a configuration has a configuration in which the stator 109 is long horizontally, the component mounting accuracy and the position accuracy of the detection coil 20 and the excitation coil 30 are the same as the accuracy of the position information from the rotary encoder 108. A big influence. Such mounting accuracy depends on the machining accuracy and manufacturing accuracy of the stator 9 and the rotor 10, and therefore an increase in cost is inevitable in order to improve accuracy. On the other hand, like the rotary encoder 8 of the first embodiment, the first detection coil 21 and the third detection coil 23 are arranged in a direction orthogonal to the traveling direction of the rotor 10, and the second detection coil 22 and the fourth detection coil are arranged. By arranging 24, the error due to the gap is less likely to occur even in the case where the stator 9 is attached to the rotor 10 at an inclination.

  The pulse signal S15 has a differential output between the first detection coil 21 and the third detection coil 23, and the pulse signal S16 has a differential output between the second detection coil 22 and the fourth detection coil 24. It can be understood that it is more resistant to errors due to the gap in the longitudinal direction than the rotary encoder 108. Therefore, the accuracy of the rotary encoder 8 can be improved, and in addition, the cost can be reduced.

  In addition, the rotor pattern 13 is configured in two rows of an outer peripheral pattern 13A serving as a first rotor pattern and an inner peripheral pattern 13B serving as a second rotor pattern, and portions having different magnetic characteristics in the moving direction of the rotor 10 are staggered. As shown, the inner peripheral pattern 13B is shifted from the outer peripheral pattern 13A, and the first detection coil 21 and the third detection coil 23, and the second detection coil 22 and the fourth detection coil 24 move the rotor 10. They are arranged in directions orthogonal to the direction. Then, S15 that is an A-phase signal is generated from the first detection coil 21 and the third detection coil 23, and a pulse signal S16 that is a B-phase signal is formed from the second detection coil 22 and the fourth detection coil 24.

  Therefore, the pulse signal S15 that is an A-phase signal is generated from the first detection coil 21 and the third detection coil 23 that are arranged in a direction orthogonal to the moving direction of the rotor 10, and is a pulse signal that is a B-phase signal. S <b> 16 is generated from the second detection coil 22 and the third detection coil 23. As a result, the influence of the magnetic flux generated in the portion other than the portion of the exciting coil 30 arranged adjacently is similarly affected. That is, since the first detection coil 21 and the third detection coil 23 and the second detection coil 22 and the fourth detection coil 24 are affected by the same magnetic flux, the influences can be offset. Therefore, the detection accuracy of the rotary encoder 8 can be improved.

  Next, a second embodiment of the present invention will be described with reference to the drawings. Although the second embodiment has the same configuration as the first embodiment, the layout of the stator is slightly different.

  FIG. 6 is a schematic diagram showing the configuration of the rotary encoder 8 of the second embodiment. FIG. 6 corresponds to FIG. 3 of the first embodiment. In the rotary encoder 8 of the second embodiment, the distance between the first detection coil 21 and the second detection coil 22 is shifted so as to advance by 180 degrees in electrical angle. The relationship between the third detection coil 23 and the fourth detection coil 24 is the same. Further, the difference between the outer peripheral pattern 13A and the inner peripheral pattern 13B of the rotor 10 is different in that the electrical angle is set to 90 degrees.

  Next, a third embodiment of the present invention will be described with reference to the drawings. The third embodiment has the same configuration as that of the first embodiment, but the layout of the stator and the rotor is slightly different, so that point will be described.

  FIG. 7 schematically shows the configuration of the rotary encoder 8 according to the third embodiment. FIG. 7 corresponds to FIG. 3 of the first embodiment. In the rotary encoder 8 of the third embodiment, the distance between the first detection coil 21 and the second detection coil 22 is shifted so as to advance by 180 degrees in electrical angle. The same applies between the third detection coil 23 and the fourth detection coil 24. On the other hand, the first detection coil 21 and the third detection coil 23 are set to advance 90 degrees in electrical angle. Further, the outer peripheral pattern 13 </ b> A and the inner peripheral pattern 13 </ b> B of the rotor 10 are arranged in a direction orthogonal to the traveling direction of the rotor 10.

  Also in the second embodiment and the third embodiment, the same effect as the first embodiment can be obtained, and the accuracy of the rotary encoder 8 can be improved. Further, it is possible to contribute to cost reduction of the rotary encoder 8.

  Next, the 4th Embodiment of this invention is described using figures. The fourth embodiment has the same configuration as that of the first embodiment, but differs in that shield members are provided on the stator and the rotor. Hereinafter, different parts will be described.

  In FIG. 8, the wiring pattern 50 provided in the stator 9 of 4th Embodiment is shown in a top view. FIG. 8 corresponds to FIG. 2 of the first embodiment. FIG. 9 shows a schematic cross-sectional view of the rotary encoder 8. In FIG. 9, the hatching process showing the cross section is not performed for convenience of explanation. The wiring pattern 50 according to the fourth embodiment is substantially the same as the wiring pattern 50 according to the first embodiment, but differs in that the copper solid pattern 40 is provided. The copper solid pattern 40 includes a first pattern 41 arranged corresponding to the left side of the first excitation coil 31 and a second pattern 42 arranged corresponding to the right side of the third excitation coil 33. The first pattern 41 is a metal plate made of a non-magnetic material (diamagnetic material) such as copper, and is installed for the purpose of preventing the connection between the wiring 35 and the first excitation coil 31 due to the influence of the rotor 10. . Similarly, the second pattern 42 is provided for the purpose of preventing the routing wiring 36 and the third excitation coil 33 from being combined due to the influence of the rotor 10.

  The rotary encoder 8 of the fourth embodiment can improve the position detection accuracy by including the first pattern 41 and the second pattern 42 as the nonmagnetic shield pattern. This is because the wiring 35 and the wiring 36 and the first excitation coil 31 and the third excitation coil 33 are coupled to generate a magnetic flux unnecessary for position detection of the rotary encoder 8, which becomes noise of the signal detected by the detection coil 20. This is because it can be prevented. As a result, the detection accuracy of the rotary encoder 8 can be improved. Note that even the shield using either the first pattern 41 or the second pattern 42 is effective in improving the detection accuracy of the rotary encoder 8, and therefore does not hinder the proper use according to the design concept.

  Next, a fifth embodiment of the present invention will be described with reference to the drawings. The fifth embodiment has the same configuration as the first embodiment, but differs in that shield members are provided on the stator 9 and the rotor 10. Hereinafter, different parts will be described.

  FIG. 10 is a plan view showing the surface of the wiring pattern 50 provided on the stator 9 of the fifth embodiment. FIG. 10 corresponds to FIG. 2 of the first embodiment. FIG. 11 is a plan view showing the back surface of the wiring pattern provided on the stator 9. FIG. 12 is a schematic cross-sectional view of the rotary encoder 8. In FIG. 12, the hatching process showing the cross section is not performed for the sake of explanation. The wiring pattern 50 of the fifth embodiment is substantially the same as the wiring pattern 50 of the first embodiment, but differs in that the copper solid pattern 40 is provided. The stator 9 is formed by laminating the detection coil 20 and the excitation coil 30, and the copper solid pattern 40 includes a first pattern 43 </ b> A and a second pattern 43 </ b> B.

  The copper solid pattern 40 is a metal plate made of a non-magnetic material (diamagnetic material) such as copper as in the fourth embodiment, and the first pattern 43A and the second pattern 43B are excited as shown in FIG. It arrange | positions so that the coil 30 may be pinched | interposed. Therefore, as shown in FIG. 12, the detection coil 20 is formed in the first layer, the first pattern 43A is formed in the second layer, the excitation coil 30 is formed in the third layer, and the second pattern 43B is formed in the fourth layer. Is done. Thus, the first pattern 43A and the second pattern 43B shield the lead wires of the first excitation coil 31, the second excitation coil 32, and the third excitation coil 33, thereby blocking magnetic flux leakage and detecting coils. Reduce dive into 20. As a result, the detection accuracy of the rotary encoder 8 can be improved.

  Next, a sixth embodiment of the present invention will be described with reference to the drawings. The sixth embodiment has the same configuration as that of the first embodiment, but differs in that shield members are provided on the stator and the rotor. Hereinafter, different parts will be described.

  FIG. 13 is a plan view showing the second layer of the wiring pattern provided on the stator 9 of the sixth embodiment. FIG. 13 corresponds to FIG. 2 of the first embodiment. FIG. 14 is a plan view showing the third layer of the wiring pattern provided on the stator 9. 13 and 14 show the detection coil 20 and the excitation coil 30 and their connection lines in an overlapping manner in order to show the positional relationship. FIG. 15 is a schematic cross-sectional view of the rotary encoder 8. In FIG. 15, the hatching process showing the cross section is not performed for convenience of explanation. The wiring pattern 50 of the sixth embodiment is substantially the same as the wiring pattern 50 of the first embodiment, but differs in that the copper solid pattern 40 is provided. The copper solid pattern 40 includes a first pattern 44A, a second pattern 44B, a third pattern 44C, a fourth pattern 44D, and a fifth pattern 44E.

  The stator 9 according to the sixth embodiment is formed in multiple layers as shown in FIG. 15, the detection coil 20 is formed in the first layer, and the first pattern 44A to the fourth pattern 44D are formed in the second layer. The fifth pattern 44E is formed in the third layer, and the exciting coil 30 is formed in the fourth layer. The copper solid pattern 40 is a metal plate made of a non-magnetic material (diamagnetic material) such as copper, and is arranged so as to shield the exciting coil 30 and its lead wire. By arranging the copper solid pattern 40 in this way, it is possible to suppress the occurrence of crosstalk between the wirings. As a result, the detection accuracy of the rotary encoder 8 is improved.

  Next, a seventh embodiment of the present invention will be described with reference to the drawings. The seventh embodiment has the same configuration as the first embodiment, but differs in that the configuration of the stator is changed. Hereinafter, different parts will be described.

  FIG. 16 is a plan view of the rotary encoder 8 according to the seventh embodiment. For convenience of explanation, it is drawn so that one surface of the stator 9 is transparent. FIG. 17 shows a right side view of the rotary encoder 8. FIG. 18 shows a left side view of the rotary encoder 8. FIG. 19 shows a plan view of the rotary encoder 8. The rotary encoder 8 of the seventh embodiment uses substantially the same wiring pattern 50 shown in FIG. 2 of the first embodiment, but the wiring 35 is arranged on one side of the stator 9 as shown in FIG. Further, as shown in FIG. 17, the routing wiring 35 and a part of the routing wiring 36 are extended so that the routing wiring 36 can be arranged on the other side of the side surface of the stator 9.

  The detection coil 20 and the excitation coil 30 are provided on the surface of the stator 9 facing the rotor 10, while the lead portion 37 is provided on the back side of the stator 9 as shown in FIG. Therefore, the wiring pattern 50 is formed across the four surfaces of the stator 9.

  In the seventh embodiment, since the wiring pattern 50 of the stator 9 is formed in this way, the influence of the change in inductance due to the movement of the rotor 10 is handled, and the wiring 35 and the handling wiring 36 are difficult to receive. As a result, noise generated in the output obtained by the detection coil 20 can be reduced, and the detection accuracy of the position data obtained by the rotary encoder 8 can be improved.

  While the present invention has been described with reference to the embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and can be appropriately modified and applied without departing from the scope of the invention. For example, in the first to third embodiments, a pattern is disclosed in which the positions of the detection coil 20 and the excitation coil 30 and the positions of the outer peripheral pattern 13A and the inner peripheral pattern 13B of the rotor 10 are changed. Does not interfere with the placement change without changing. In addition, the materials shown in the embodiment are not prevented from being changed to other materials that perform this function. In addition, the illustrated sizes and the like are shown only for reference, and thus are not prevented from being changed according to the design concept.

8 Rotary encoder 9 Stator 10 Rotor 11 Magnetic part 12 Nonmagnetic part 13 Rotor pattern 13A Outer pattern 13B Inner pattern 20 Detection coil 21 First detection coil 22 Second detection coil 23 Third detection coil 24 Fourth detection coil 30 Excitation coil 31 First excitation coil 32 Second excitation coil 33 Third excitation coil 35 Wiring 36 Wiring 37 Lead portion 40 Copper solid pattern 50 Wiring pattern

Claims (6)

A stator having four detection coils and three exciting coils formed in a plane and a rotor having two rows of rotor patterns in which portions having different magnetic properties are alternately arranged along the moving direction are opposed to each other. In the position sensor arranged in
The four detection coils (first detection coil, second detection coil, third detection coil, and fourth detection coil) are in the moving direction of the rotor with respect to the rotor pattern,
The first detection coil and the second detection coil are arranged side by side;
Similarly, the third detection coil and the fourth detection coil are arranged side by side,
The first detection coil and the third detection coil are arranged in a direction orthogonal to the moving direction of the rotor with respect to the rotor pattern,
The three excitation coils (first excitation coil, second excitation coil, and third excitation coil) are connected in series,
The winding directions of the adjacent excitation coils are arranged differently in the order of the first excitation coil, the second excitation coil, and the third excitation coil in the moving direction of the rotor,
The right side of the first excitation coil is along the left side of the first detection coil and the third detection coil,
The left side of the second excitation coil is along the right side of the first detection coil and the third detection coil,
The right side of the second excitation coil is along the left side of the second detection coil and the fourth detection coil,
The left side of the third excitation coil is disposed along the right side of the second detection coil and the fourth detection coil,
The third detection coil and the fourth detection coil are arranged in the rotor pattern so that a phase is shifted by 1/4 with respect to a period;
A position sensor characterized by. The position sensor according to claim 1,
The rotor pattern is configured in two rows of a first rotor pattern and a second rotor pattern, and the rotor pattern is arranged in a staggered manner with respect to the first rotor pattern such that portions having different magnetic characteristics are arranged in a staggered manner in the moving direction of the rotor. The second rotor pattern is shifted and arranged;
The first detection coil and the third detection coil, the second detection coil and the fourth detection coil are arranged in a direction orthogonal to the moving direction of the rotor, respectively.
A phase signal is generated from the first detection coil and the third detection coil,
Forming a B-phase signal from the second detection coil and the fourth detection coil;
A position sensor characterized by. The position sensor according to claim 1 or 2,
The stator is arranged such that a lead wire connected to the excitation coil or the detection coil and the excitation coil are covered with a shield pattern made of a nonmagnetic conductor so that the side of the excitation coil on the side where the excitation coil is disposed is covered. Arranged on the side facing the rotor,
A position sensor characterized by. The position sensor according to any one of claims 1 to 3,
The excitation coil, the detection coil, and the lead wire connected to the excitation coil or the detection coil are formed by being laminated,
Arranging the lead wire connected to the exciting coil so as to be sandwiched between shield patterns made of a non-magnetic conductor;
A position sensor characterized by. The position sensor according to any one of claims 1 to 4,
The excitation coil and the extraction line of the detection coil have a portion formed in a separate layer, and a shield pattern made of a nonmagnetic conductor corresponding to at least a portion thereof is disposed between the layers,
A position sensor characterized by. The position sensor according to any one of claims 1 to 5,
The lead wire connected to the excitation coil or the detection coil is disposed on a surface different from the facing surface where the excitation coil or the detection coil and the rotor pattern face each other;
A position sensor characterized by.

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