Rotational speed detection device, rotational speed detection system and rotational speed calculation device

Abstract

Rotational speed detection device, comprising a magnet wire in which an alternating magnetic field with two or more cycles per revolution in an axial direction is provided corresponding to a rotational operation of a rotator, wherein the magnet wire outputs a pulse with a polarity that depends on a change in one direction of a magnetic field; a magnetic polarity determination unit that determines the polarity of a magnet forming the alternating magnetic field and contained in the rotator at a predetermined relative position with respect to the magnet wire; and a calculation unit that calculates a count value by counting a segment in a circumferential direction of the rotator, wherein The calculation unit calculates the count value based on a polarity of the rotator's magnet that was last detected, a polarity of the pulse from that time, and a polarity of the rotator's magnet at the time the pulse from that time is generated, and without using a polarity of the pulse from the last time.

Description

BACKGROUND 1. TECHNICAL AREA

[0001] The present invention relates to a rotational speed detection device, a rotational speed detection system and a Rotational speed calculation device. 2. STATE OF THE ART

[0002] A device for detecting multiple rotation angles using a current generation sensor is conventionally known (see, for example, patent document 1).

[0003] Patent document 1: Japanese patent application no. 2024-106245

[0004] When calculating the rotational speed of a rotator, reference information is reduced. SUMMARY

[0005] To solve the problem described above, the first aspect of the present invention provides a rotational speed detection device comprising a magnet wire in which an alternating magnetic field with two or more cycles per revolution in an axial direction is provided, corresponding to a rotational operation of a rotator. The magnet wire outputs a pulse with a polarity that depends on a change in the direction of the magnetic field. The rotational speed detection device described above may include a magnetic polarity determination unit that determines the polarity of a magnet forming the alternating magnetic field and contained within the rotator at a predetermined relative position with respect to the magnet wire. Each of the rotational speed detection devices described above may include a calculation unit that calculates a count value by counting a segment in a circumferential direction of the rotator.In each of the rotational speed detection devices described above, the calculation unit can calculate the count value based on a polarity of the rotator's magnet that was last detected, a polarity of the pulse from that time, and a polarity of the rotator's magnet at the time the pulse from that time is generated, and without using a polarity of the pulse from the last time.

[0006] In each of the rotational speed sensing devices described above, the computational unit, when triggered by the pulse to initiate a count calculation, can detect, based on the polarity of the rotator's magnet last detected, the polarity of the current pulse, and the polarity of the rotator's magnet at the time the current pulse is generated, that another segment adjacent to the segment opposite the magnet wire will move to a position opposite the magnet wire at the time the current pulse is generated. Each of the rotational speed sensing devices described above can include a storage unit that integrates the count calculated by the computational unit to store the integrated count as an integrated value.

[0007] In each of the rotational speed detection devices described above, the calculation unit can differentiate the count value for at least one polarity of the pulse from this time, depending on whether the polarity of the rotator's magnet from last time and the polarity of the rotator's magnet from this time match or not.

[0008] In each of the rotational speed detection devices described above, if the polarity of the rotator's magnet from the last measurement matches the polarity of the rotator's magnet this time, the calculation unit can output a count value where the integrated value is maintained. Conversely, in each of the rotational speed detection devices described above, if the polarity of the rotator's magnet from the last measurement differs from the polarity of the rotator's magnet this time, the calculation unit can output a count value where the integrated value is either decreased or increased.

[0009] In each of the rotational speed detection devices described above, the calculation unit can distinguish a sign of the count value, depending on whether the polarity of the rotator's magnet and the polarity of the pulse match this time or not.

[0010] In each of the rotational speed detection devices described above, the magnet wire can be arranged to output the pulse when a limit of a rotator's magnetization deviates from an opposite position.

[0011] In each of the rotational speed sensing devices described above, the magnetic wire can extend in a direction that intersects a tangent to the rotator.

[0012] In each of the rotational speed detection devices described above, the magnetic polarity determination unit can be a magnetic sensor. In each of the rotational speed detection devices described above, the magnetic sensor can be arranged so that it does not face any boundary of the rotator's magnetization, provided that the magnet wire and the boundary of the rotator's magnetization are positioned facing each other.

[0013] In each of the rotational speed detection devices described above, the magnetic sensor can be arranged to have the greatest possible distance from the limit of magnetization of the rotator when the magnet wire and the limit of magnetization of the rotator are positioned facing each other.

[0014] In each of the rotational speed detection devices described above, the rotator can be magnetized at four poles.

[0015] In each of the rotational speed detection devices described above, the magnetic sensor can be arranged in a range of 45±10 degrees or 135±10 degrees from the magnet wire around a rotational axis of the rotator.

[0016] In each of the rotational speed sensing devices described above, the rotator can be magnetized on n poles. In each of the rotational speed sensing devices described above, the magnetic sensor can be offset by any value θ within a range of ±40 / n degrees. m be arranged at an angle of the magnet wire around a rotational axis of the rotator. θm=±180×m / n

[0017] It should be noted that m can be any odd number smaller than n.

[0018] To solve the problem described above, the second aspect of the present invention provides a rotational speed detection system comprising one of the rotational speed detection devices described above and the rotator.

[0019] To solve the problem described above, the third aspect of the present invention provides a rotational speed calculation device that calculates a count value by counting a segment in a circumferential direction of a rotator, based on an output from a magnet wire and a magnetic polarity determination unit. In the rotational speed calculation device described above, the magnet wire can be provided with an alternating magnetic field of two or more cycles per revolution in an axial direction corresponding to a rotational operation of the rotator and output a pulse with a polarity that depends on a change in the direction of a magnetic field.In each of the rotational speed calculation devices described above, the magnetic polarity determination unit can determine the polarity of a magnet forming the alternating magnetic field and contained within the rotator at a predetermined relative position with respect to the magnet wire. Each of the rotational speed calculation devices described above can calculate the count value based on the polarity of the rotator's magnet last detected, the polarity of the pulse from that detection, and the polarity of the rotator's magnet at the time the pulse from that detection is generated, as well as without using the polarity of the pulse from the last detection.

[0020] To solve the problem described above, a rotational speed detection method is provided in the fourth aspect of the present invention. The rotational speed detection method described above can include detecting the polarity of a pulse from a magnet wire in which an alternating magnetic field with two or more cycles per revolution in an axial direction is provided, corresponding to a rotational operation of a rotator. The polarity of the pulse is output by the magnet wire as a function of a change in the direction of the magnetic field. Each of the rotational speed detection methods described above can include detecting, at a predetermined relative position with respect to the magnet wire, the polarity of a magnet that forms the alternating magnetic field and is contained within the rotator.Each of the rotational speed detection methods described above can include calculating a count value by counting a segment in a circumferential direction of the rotator, based on a polarity of the rotator's magnet last detected, a polarity of the pulse from that time, and a polarity of the rotator's magnet at the time the pulse from that time is generated, and without using a polarity of the pulse from the last time.

[0021] It should be noted that the summary clause does not necessarily describe all the necessary features of the embodiments of the present invention. The present invention may also be a subcombination of the features described above. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows an example of a rotational speed detection system 200. Fig. Figure 2 shows an arrangement example of a magnet wire 10, a magnetic polarity determination unit 14 and a magnet 20. Fig. 3A shows the polarity of a pulse emitted by the magnet wire 10 and the polarity of the magnet 20 determined by the magnetic polarity determination unit 14. Fig. Figure 3B shows a relationship between the polarity of the pulse, the polarity of magnet 20 and a count value. Fig. 4A shows the polarity of a pulse emitted by the magnet wire 10 and the polarity of the magnet 20 determined by the magnetic polarity determination unit 14 in patent document 1. Fig. Figure 4B shows a relationship between the polarity of the pulse, the polarity of magnet 20 and the count value in patent document 1. Fig. Figure 5A shows the polarity of the pulse and the polarity of the magnet 20 in a case where the arrangement of the magnet wire 10 and the magnetic polarity determination unit 14 in patent document 1 is the same as in Fig. 3A. Fig. 5B shows a relationship between the polarity of the pulse, the polarity of magnet 20 and the count value of Fig. 5A. Fig. Figure 6A shows the polarity of the pulse and the polarity of the magnet 20 in a case where the arrangement of the magnet wire 10 and the magnetic polarity determination unit 14 is different in the example. Fig. Figure 6B shows the relationship between the polarity of the pulse, the polarity of magnet 20, and the count value in Fig. 6A. Fig. Figure 7 is a flowchart showing an example of a rotational speed detection method for a rotator 30. Fig. Figure 8A shows a relative position of the magnetic polarity determination unit 14 relative to the magnet wire 10. Fig. Figure 8B is another figure that describes the relative position of the magnetic polarity determination unit 14 relative to the magnet wire 10. Fig. Figure 9 is a perspective view showing an example of the arrangement of the magnet 20, the magnetic polarity determination unit 14 and the magnet wire 10. DESCRIPTION OF EXAMPLE EXECUTION FORMS

[0022] The present invention is described below with reference to embodiments of the invention, the following embodiments of which do not limit the invention according to the claims. Furthermore, not all combinations of features described in the embodiments are essential for the solvents of the invention. In this description, the same part is designated by the same reference numeral in each figure of the embodiments, and its description may be omitted. Additionally, some components may not be shown to simplify the description.

[0023] In this description, technical situations can be described using orthogonal coordinate axes: an X-axis, a Y-axis, and a Z-axis. These orthogonal coordinate axes simply indicate the relative positions of the components and do not restrict any specific direction. For example, the Z-axis direction is not limited to indicating the vertical direction relative to the ground. It is important to note that a +Z-axis direction and a -Z-axis direction are opposite directions. When the Z-axis direction is described without specifying a sign, it means that the direction is parallel to both the +Z-axis and the -Z-axis.

[0024] In the present description, the terms "equal," "equivalent," "parallel," or "perpendicular" may also include a case where an error exists due to manufacturing tolerances or similar factors. For example, the error may be within 10%.

[0025] Fig. Figure 1 shows an example of a rotational speed detection system 200. Fig. Figure 1 shows a cross-section of the rotational speed detection system 200. The rotational speed detection system 200 comprises a rotator 30, a rotational speed detection device 100, a support base 40, and a support element 42. The rotational speed detection device 100 detects the rotation of the rotator 30. The rotational speed detection device 100 detects at least one of the rotational speeds or the direction of rotation of the rotator 30. The rotational speed detection system 200 may further include a single-revolution sensor that detects the angle of rotation within one rotational cycle of the rotator 30.

[0026] The rotator 30 of the present example has a rotation axis 32 and a mounting section 34. For example, the rotation axis 32 could be a rotation axis of a motor or an axis of a stage. Fig. 1. The axis of rotation 32 extends in a Z-axis direction. The mounting section 34 is attached to the axis of rotation 32. In Fig. 1. The rotator 30 rotates in the XY plane with the Z-axis direction as one axial direction.

[0027] The mounting section 34 has a magnet 20. The magnet 20 is a multipole magnet. The magnet 20 has two or more first pole sections 21 and two or more second pole sections 22. One of the first pole sections 21 and one of the second pole sections 22 is an N pole, and another is an S pole. Fig. In Figure 1 and the following drawings, the first polar section 21 is shown hatched.

[0028] The rotator 30 is magnetized along its direction of rotation at four or more poles. The fact that the rotator 30 is magnetized means that the rotator 30 itself can be magnetized, or that, as in the present example, the magnet 20 with four or more poles can be attached to the rotator 30. The first pole section 21 and the second pole section 22 of the present example are arranged alternately along the direction of rotation of the rotator 30. The direction of rotation is the direction in which the rotator 30 rotates, viewed from the axial direction of the rotator 30 (Z-axis direction) and the circumferential direction of a circle around an axis of rotation 32. For example, the first pole section 21 is arranged circumferentially adjacent to the second pole section 22, which is located in Fig. Figure 1 shows the second pole section 22 being arranged circumferentially adjacent to the first pole section 21. Viewed from the Z-axis direction, two or more of the first pole sections 21 and the second pole sections 22 can each be arranged along the circumferential direction, or three or more can be arranged.

[0029] The magnet 20 can have a columnar shape or it can have a cavity oriented in a direction perpendicular to the base of the cylinder. That is, the magnet 20 can be a cylindrical ring magnet. A cylindrical cavity section of the magnet 20 in the present example overlaps the axis of rotation 32 in the Z-axis direction. The magnet 20 rotates together with the rotator 30.

[0030] The rotational speed detection device 100 comprises a magnetic wire 10, a magnetic polarity determination unit 14, and a calculation unit 16. The rotational speed detection device 100 may also include a storage unit 18. Fig. Figure 1 shows the XZ cross-section of the rotational speed sensing device 100 and the rotator 30. It should be noted that some components may not be present in the same cross-section. Fig. 1. All components are shown in the same cross-section for illustration purposes.

[0031] The magnet wire 10, the magnetic polarity determination unit 14, the calculation unit 16, and the storage unit 18 are attached to the support base 40. The support base 40 is attached to the support element 42 and is positioned so that it faces the rotator 30 in the Z-axis direction. The shape of the rotator 30, the magnet 20, the support base 40, and the support element 42 can each be a circular shape around the axis of rotation 32 in the XY plane. In the present example, the support base 40 does not rotate.

[0032] The magnet wire 10 can be a wire having superimposed layers of materials with different magnetic sensitivities, i.e., a Wiegand wire. The magnet wire 10 has a first material 11 and a second material 12. By encasing the first material 11 with the second material 12, a double-layer structure wire is formed. A coil can be wound around the magnet wire 10.

[0033] The first material 11 and the second material 12 each exhibit different magnetic sensitivities. In this example, the first material 11 is hard magnetic and the second material 12 is soft magnetic. When the strength of an external magnetic field changes gradually, only the orientation of the magnetization of the second material 12 changes, as it exhibits high magnetic sensitivity at that magnetic field strength. At this point, a pulse is generated at the coil wound around the magnet wire 10. The pulse can be a voltage pulse, a current pulse, or both. It should be noted that the magnetic sensitivity of the first material 11 of the magnet wire 10 can be higher than the magnetic sensitivity of the second material 12.

[0034] When the rotator 30 rotates, the magnet 20 rotates relative to the magnet wire 10, thereby changing the strength and direction of the magnetic field exerted by the magnet 20 on the magnet wire 10. The magnet wire 10 emits a pulse with a polarity that depends on the change in the direction of the magnetic field. The magnet wire 10 can emit a pulse with a polarity that depends on the change in both the strength and direction of the magnetic field. There are two types of pulse polarity, depending on the direction in which the second material 12 is magnetized. In this description, the polarity of the pulse is represented by positive (+) and negative (-). That is, the magnet wire 10 generates a pulse by rotating the rotator 30.In other words, an alternating magnetic field is generated by the magnet 20 two or more times per revolution, then this alternating magnetic field is applied in the longitudinal direction of the magnet wire 10, and as a result, the magnet wire 10 emits a pulse that depends on the change in the direction of the magnetic field.

[0035] The magnetic polarity detection unit 14 determines the polarity of the magnet 20 of the rotator 30. The magnetic polarity detection unit 14 can be a magnetic sensor. The magnetic polarity detection unit 14 in the present example is a Hall effect sensor. It should be noted that the magnetic polarity detection unit 14 is not limited to the magnetic sensor, as long as the polarity of the magnet 20 of the rotator 30 can be determined. For example, the polarity of the magnet 20 can be determined by forming a recess on the rotator 30 that depends on the polarity of the magnet 20 and then measuring the recess using an optical sensor.

[0036] The computation unit 16 is a rotational speed computation device that calculates a count value representing the rotational speed of the rotator 30. The computation unit 16 calculates the count value based on the output of the magnet wire 10 and the magnetic polarity detection unit 14. A calculation method for the count value is described below. The computation unit 16 can read information from the storage unit 18 to calculate the count value. The computation unit 16 outputs the calculated count value to the storage unit 18. The computation unit 16 and the magnetic polarity detection unit 14 of this example are configured by an integrated IC with a Hall sensor. It should be noted that the computation unit 16 can be provided separately from the magnetic polarity detection unit 14.

[0037] The storage unit 18 integrates the count value calculated by the computation unit 16 to store the integrated count value as an integrated value. The storage unit 18 can be a low-power, non-volatile memory, such as FRAM (registered trademark) or similar. Although not shown, the magnet wire 10, the magnetic polarity detection unit 14, the computation unit 16, and the storage unit 18 can be coupled by wiring.

[0038] The magnetic polarity determination unit 14, the calculation unit 16, and the storage unit 18 can be powered by the electrical energy of a pulse emitted by the magnet wire 10. In this way, the rotational speed of the rotator 30 can be calculated and maintained even without a power supply from a battery or the like. The magnetic polarity determination unit 14 can determine the polarity of the magnet 20 of the rotator 30 each time a pulse is generated. The calculation unit 16 can calculate the count value by reading information from the storage unit 18 each time the pulse is generated and can write the calculated count value or the like to the storage unit 18. An external capacitor can be provided to the calculation unit 16 to charge the electrical energy of the pulse from the magnet wire 10. Furthermore, the calculation unit 16 can rectify the pulse from the magnet wire 10.

[0039] Fig. Figure 2 shows an arrangement example of a magnet wire 10, a magnetic polarity determination unit 14 and a magnet 20. Fig. Figure 2 shows an example arrangement for a case in which the magnet wire 10, the magnetic polarity determination unit 14 and the magnet 20 are inserted from the negative side in the Z-axis direction. Fig. 1. (This appears to be a fragment and is omitted.) Fig. No further component is shown for the description in section 2. Furthermore, the entire magnet wire 10 is marked with coarse hatching.

[0040] The magnet 20 of the present example has two first pole sections 21 and two second pole sections 22 on its circumference in the XY plane. The magnet 20 of the present example has a first pole section 21 and a second pole section 22 every 90 degrees in the circumferential direction.

[0041] The magnet wire 10 of the present example can extend in a predetermined direction. For example, one direction of extension of the magnet wire 10 with a columnar shape is a direction perpendicular to a circular cross-section. Fig. 2. The magnet wire 10 extends in the direction of the X-axis. In the present description, the direction of the magnet wire 10 can be the direction of extension of the magnet wire 10.

[0042] The magnet wire 10 can be arranged to emit a pulse when the boundary of the rotator 30's magnetization deviates from an opposite position. In this example, the boundary of the rotator 30's magnetization is the boundary between the first pole section 21 and the second pole section 22 of the magnet 20. The magnet wire 10 can extend in a direction that intersects a tangent to the rotator 30. The directions of the tangent to the rotator 30 and the tangent to the magnet 20 can coincide. The magnet wire 10 in this example is orthogonal to the tangent to the magnet 20. By such an arrangement, the magnet wire 10 emits a pulse, as described below, when the boundary of the rotator 30's magnetization deviates from an opposite position.

[0043] The magnetic polarity determination unit 14 is arranged at a predetermined relative position with respect to the magnet wire 10. In this example, the magnetic polarity determination unit 14 is positioned 45 degrees from the magnet wire 10, with the center of the circle of the magnet 20 serving as a reference. At this position, the magnet wire 10 can be arranged to overlap the magnet 20 in the Z-axis direction. The magnetic polarity determination unit 14 determines the polarity (an N pole, an S pole) of the magnet 20 at this position.

[0044] Fig. 3A shows the polarity of a pulse emitted by the magnet wire 10 and the polarity of the magnet 20 determined by the magnetic polarity determination unit 14. Fig. Figure 3B shows a relationship between the polarity of the pulse, the polarity of magnet 20, and a count value. In the present example, the first pole section 21 of magnet 20 is the N pole and the second pole section 22 is the S pole.

[0045] In the present example, the magnet wire 10 is arranged in a direction that intersects the tangent of the magnet 20. The magnet wire 10 emits a pulse when the magnet 20 rotates, and the boundary of the first pole section 21 and the second pole section 22 deviates from a position relative to the magnet wire 10. The points a to h marked with black circles in the figure are points whose boundary deviates from the position relative to the magnet wire 10, and the magnet wire 10 emits a pulse when each point reaches the position relative to the magnet wire 10.

[0046] The arrow shown outside each point indicates that the pulse is emitted when magnet 20 is rotated in the orientation of the arrow. The triangle shown further outside than the arrow indicates the polarity of the pulse. In this example, the pulse with positive polarity is represented by an inward-pointing triangle, and the pulse with negative polarity is represented by an outward-pointing triangle.

[0047] The circle marked further out than the triangle indicates the polarity of magnet 20 as detected by the magnetic polarity detection unit 14 at the time of pulse generation. The hatched circle marks the first pole segment 21, and the unhatched circle marks the second pole segment 22. The magnetic polarity detection unit 14 of this example detects the polarity of magnet 20 in a segment opposite the magnetic polarity detection unit 14 at the time of pulse generation.

[0048] As an example, a case is described in which magnet 20 is moved from the state of Fig. 3A is rotated clockwise. Even if the rotation continues and point d is rotated to the position opposite the magnet wire 10, no pulse is output because point d is a counterclockwise arrow. If the rotation continues subsequently and point c is rotated to the position opposite the magnet wire 10, the pulse is output because point c is a clockwise arrow. The polarity is positive at this point. This is a pulse generated by the magnet wire 10 as a result of only the second material 12 being magnetized in the opposite direction by the magnetic field of the first pole section 21, after the first material 11 and the second material 12 of the magnet wire 10 have been magnetized in the same direction by the magnetic field of the second pole section 22.Furthermore, the polarity of magnet 20, which is detected at this time by the magnetic polarity determination unit 14, is the first pole section 21 (the N pole). In the table of . Fig. In section 3B, "last time", the polarity of the pulse is shown as positive in the case of position c, and the polarity of magnet 20 (MS) is given as N(+). In the present example, when calculating the count value, the N pole is treated as +.

[0049] There are four positions: point c, point d, point f, and point a, at which the pulse can be generated after the pulse was generated at point c the last time. In the "this time" section of Fig. Figure 3B shows the individual points in each row in this order. First, a case is described in which the pulse is generated at point c this time. In this case, the magnet 20 begins a counter-rotation (counterclockwise), having barely rotated clockwise after the pulse was generated at point c the last time. At this point, the first material 11 of the magnet wire 10 is not magnetized by the magnetic field of the first pole section 21 of the magnet 20. Therefore, the pulse is not generated, even if the magnet 20 is rotated counterclockwise and point d is rotated to the position opposite the magnet wire 10. In this way, a phenomenon in which the pulse is not generated at a position where the pulse should actually be generated is called a "pulse omission".If magnet 20 is then rotated clockwise again and point c is rotated to the position opposite magnet wire 10, the pulse is generated. The polarity of the pulse is positive at this time, the polarity of magnet 20 (MS) is N(+), and these are in the row of point c in the section “this time” in . Fig. Figure 3B shows that both the pulse polarity and the polarity of magnet 20 are the same as in the case of point c from the last time. It should be noted that "last time" in this description refers to the time at which the pulse was last generated, and "this time" refers to the time at which the pulse is generated this time.

[0050] A case is then described in which the pulse is generated at point d. In this case, the magnet 20 is rotated clockwise until the first material 11 of the magnet wire 10 is magnetized by the magnetic field of the first pole section 21, after the pulse was generated at point c previously. The pulse is then generated when the direction of rotation is reversed counterclockwise, so that point d is rotated to the position opposite the magnet wire 10. The polarity of the pulse is negative at this point, and the polarity of the magnet 20 (MS) is N(+).

[0051] A case is then described in which the pulse is generated at point f. This case is similar to the case at point c, in that magnet 20 is rotated counterclockwise, the pulse omission is generated, and the pulse is not generated at point d. If magnet 20 then continues to rotate counterclockwise and point f is rotated to the position opposite the magnet wire 10, the pulse is generated. The polarity of the pulse is positive at this point, and the polarity of magnet 20 (MS) is S(-).

[0052] A case is then described in which the pulse is generated at point a. In this case, after the pulse was generated at point c the previous time, magnet 20 continues to rotate clockwise. When point a is then rotated to the position opposite the magnet wire 10, the pulse is generated. The polarity of the pulse is negative at this point, and the polarity of magnet 20 (MS) is S(-).

[0053] The calculation of the count value is then described. The count value is a value that indicates the rotational speed of rotator 30. In this example, a count value of 4 corresponds to one revolution. The count value is found in the rightmost column of the table in Fig. 3B is given. In the count value of the present example, clockwise (CW; eng. clock wise) is positive (+) and counterclockwise (CCW; eng. counter clock wise) is negative (-). In other words, as in Fig. As shown in Figure 3A, the rotator 30 or the magnet 20 is defined such that, when a rotational coordinate system is set around an axis of rotation, it has four segments (quadrants) divided by two axes passing through the axis of rotation and perpendicular to it. The count value decreases or increases depending on the change in the segments facing the magnet wire 10 due to the rotation. The determination between increasing and decreasing the count value is further determined by combining it with the result of the detection by the magnetic polarity determination unit 14. It should be noted that, in addition to the above definition, the segment can, for example, be defined as a region with a predetermined angular width in the direction of rotation around the axis of rotation.In other words, if one revolution consists of four counts, for example, an area corresponding to an angular width of 90 degrees in the direction of rotation can be designated as a segment. A segment facing the magnet wire 10 is a segment whose distance to a placement position of the magnet wire 10 is shortest among a plurality of segments contained in the rotator 30 and changes depending on the rotation operation.

[0054] In a case where the pulse generation position was point c last time and the pulse generation position is point c this time, the count value is 0. This corresponds to the fact that the pulse was generated both this time and last time at point c. Fig. 3A is generated in quadrant 2. In a case where the pulse generation position last time was point c and the pulse generation position this time is point d, the count value is 0. This also corresponds to the fact that the pulse is generated in quadrant 2 both this time and last time. Fig. 3A is generated.

[0055] In a case where the pulse generation position last time was point c and the pulse generation position this time is point f, the count value is -1. This corresponds to the fact that in Fig. 3A the pulse from last time is generated in quadrant 2 and the pulse from this time is generated in quadrant 3. In a case where the pulse generation position last time is point c and the pulse generation position this time is point a, the count value is +1. This corresponds to the fact that in Fig. 3A the pulse from last time is generated in quadrant 2 and the pulse from this time is generated in quadrant 1.

[0056] The calculation of the in Fig. The count value shown in Figure 3B is an example, and the procedure can be summarized as follows. The computation unit 16 calculates the count value based on the polarity of magnet 20 from the last time, the polarity of the pulse from this time, and the polarity of magnet 20 from this time. Furthermore, the computation unit 16 calculates the count value without using the polarity of the pulse from the last time. In other words, the computation unit 16 calculates the count value by counting the segments in a circumferential direction (here a 4-segment configuration) of the rotator 30 as a function of the rotation of the rotator 30 on which the magnet 20 is installed. The description is given in more detail below. When an alternating magnetic field generated by the rotation of the magnet 20 contained in the rotator 30 is applied to the magnet wire 10, a pulse is generated as a function of a change in the direction of the magnetic field.The magnetic polarity determination unit 14 then determines the polarity of the magnet 20 at a predetermined relative position with respect to the magnet wire 10 in response to the generation of the pulse. This operation can be viewed as counting the number of times a segment facing the magnet wire 10 is transformed into an adjacent segment due to the rotation operation of the rotator 30, for a plurality of segments virtually defined as a region with a predetermined angular width across the circumferential direction of the rotator 30.

[0057] Depending on whether the polarity of magnet 20 from the last time and the polarity of magnet 20 this time match or not, the calculation unit 16 can differentiate the count value for at least one polarity of the pulse from this time. In the Fig. In the example shown in 3B, the count value is the same regardless of the pulse polarity (count value 0) if the polarity of magnet 20 from last time and the polarity of magnet 20 this time are the same (point c and point d of "this time"). If the polarity of magnet 20 from last time and the polarity of magnet 20 this time are different (point f and point a of "this time"), the count value is differentiated for the pulse polarity as +1 and -1.

[0058] If the polarity of magnet 20 from last time and the polarity of magnet 20 from this time are the same (point c and point d from "this time"), the calculation unit 16 can output the count value, where the integrated value is retained. Fig. 3B is the count value 0. If the polarity of magnet 20 from last time and the polarity of magnet 20 from this time are different (point f and point a from "this time"), the calculation unit 16 can output the count value at which the integrated value is decreased or increased. In Fig. 3B is the count value +1 or -1.

[0059] The calculation unit 16 can differentiate the sign of the count value, depending on whether the polarity of magnet 20 and the polarity of the pulse match this time or not. Fig. 3B, if the polarity of magnet 20 from last time and the polarity of magnet 20 this time are different (point f and point a of "this time"), if the polarity of magnet 20 this time and the polarity of the pulse this time are the same (point a), the sign is negative, and if the polarity of magnet 20 this time and the polarity of the pulse this time are different (point f), the sign is positive. In this case, the absolute value of the count can be the same. Fig. 3B has a count value of +1 if point a is selected this time, and a count value of -1 if point f is selected this time. That is, the absolute value is 1.

[0060] As described above, calculation unit 16 calculates the count value without using the polarity of the last pulse. This means that when calculating one of the count values ​​described above, the count value is calculated without using the polarity of the last pulse. This reduces the amount of reference information required when calculating the count value.

[0061] During the calculation of the count value, the processing unit 16 can read the polarity of magnet 20 from memory unit 18 from the last time. The processing unit 16 cannot read the polarity of the pulse from memory unit 18 from the last time during the calculation of the count value. The processing unit 16 can only calculate the count value based on the polarity of magnet 20 from the last time, the polarity of the pulse this time, and the polarity of magnet 20 this time.

[0062] The processing unit 16 can write the calculated count value to the storage unit 18. The processing unit 16 can write information about the polarity of magnet 20 from this time to the storage unit 18. This allows the polarity to be read as the polarity of magnet 20 from the last time at the time of the next pulse generation. The processing unit 16 cannot write information about the polarity of the pulse from this time to the storage unit 18. The storage unit 18 can store the information about the polarity of magnet 20. The storage unit 18 cannot store the information about the polarity of the pulse.

[0063] Fig. Figure 4A shows the polarity of a pulse emitted by the magnet wire 10 and the polarity of the magnet 20 determined by the magnetic polarity determination unit 14 in patent specification 1. Fig. Figure 4B shows a relationship between the polarity of the pulse, the polarity of magnet 20, and the count value in patent specification 1. Fig. 1, Fig. Figures 2A to 2C of Patent Specification 1 show a current generation sensor 20 arranged in an orientation parallel to a tangent of a magnetic field source 50, which is a four-pole magnetized magnet, and a sensor element MS arranged to detect the polarity of a magnetic pole opposite the central section of the current generation sensor 20 (paragraph 0079). The arrangement of the individual components of Patent Specification 1, the polarity of the pulse to be generated, and the polarity of the magnet 20 are shown using the illustration in Fig. 3A of the present specification in Fig. 4A is shown.

[0064] Since in Fig. Since the magnet wire 10 is arranged in an orientation parallel to the tangent of the magnet 20, the pulse generation position differs from that in Fig. 3A. Furthermore, the magnetic polarity determination unit 14 detects the polarity of the magnet 20 in a section opposite the magnet wire 10.

[0065] Similar to the case in Fig. 3A describes a case in which magnet 20 moves from a state in Fig. 4A is rotated clockwise. As the rotation progresses and point d is turned to a position opposite the center of the magnet wire 10, a pulse is emitted. At this point, the polarity is negative. Furthermore, the polarity of the magnet 20, which is detected at this point by the magnetic polarity determination unit 14, is the second pole section 22. In the table of Fig. In section 4B, the polarity of the pulse in the case of position d is given as negative and the polarity of magnet 20 (MS) as S(-).

[0066] There are four positions: point d, point e, point g, and point b, at which the pulse can be generated after the pulse was generated at point d the last time. In the "this time" section of Fig. In Figure 4B, the individual points in each row are shown in this order. First, a case is described in which the pulse is generated at point d this time. In this case, magnet 20 begins a counter-rotation (counterclockwise) after the pulse was generated at point d the last time. Then, a pulse omission is generated at point e. Subsequently, when magnet 20 is rotated clockwise again and point d is rotated to the position opposite the center of the magnet wire 10, the pulse is generated. The polarity of the pulse is negative at this time, the polarity of magnet 20 (MS) is S(-), and these are shown in the row of point d in the section "this time" in Figure 4B. Fig. Figure 3B shows that both the pulse polarity and the polarity of magnet 20 are the same as in the case of point d from last time.

[0067] A case is then described in which the pulse is generated at point e. In this case, the magnet 20 is rotated clockwise until the first material 11 of the magnet wire 10 is also magnetized, after the pulse was generated at point c the previous time. Subsequently, the pulse is generated when the direction of rotation is changed counterclockwise, so that point e is rotated to the position opposite the center of the magnet wire 10. The polarity of the pulse is positive at this point, and the polarity of the magnet 20 (MS) is S(-).

[0068] A case is then described in which the pulse is generated at point g. This case is similar to the case of point d in that magnet 20 is rotated counterclockwise, the pulse omission is generated, and the pulse is not generated at point e. If magnet 20 is subsequently rotated further counterclockwise and point g is rotated to the position opposite the center of the magnet wire 10, the pulse is generated. The polarity of the pulse is negative at this point, and the polarity of magnet 20 (MS) is N(+).

[0069] Next, a case is described in which the pulse is generated at point b. In this case, after the pulse was generated at point d the previous time, magnet 20 continues to rotate clockwise. When point b is then rotated to the position opposite the center of the magnet wire 10, the pulse is generated. The polarity of the pulse is positive at this time, and the polarity of magnet 20 (MS) is N(+).

[0070] The calculation of the count value is then described. The method used to determine the count value is similar to that used in the case of Fig. 3B. In a case where the pulse generation position was point d last time and the pulse generation position is point d this time, the count value is 0. This corresponds to the fact that the pulse was generated both this time and last time at point d. Fig. 4A is generated in quadrant 2. In a case where the pulse generation position last time is point d and the pulse generation position this time is point e, the count value is -1. This corresponds to the fact that the pulse last time was in quadrant 2 and the pulse this time is in quadrant 3. Fig. 4A is generated.

[0071] In a case where the pulse generation position last time was point d and the pulse generation position this time is point g, the count value is -2. This corresponds to the fact that the pulse last time was in quadrant 2 and the pulse this time is in quadrant 4. Fig. 4A is generated. In a case where the pulse generation position last time is point d and the pulse generation position this time is point b, the count value is +1. This corresponds to the fact that the pulse last time was in quadrant 2 and the pulse this time is in quadrant 1. Fig. 4A is generated.

[0072] In Fig. In section 4B, the count value is -2. If we consider a point other than point d, the count value +2 exists, and therefore, in the example of Fig. 4A has an absolute value of 2 in the count value. In Fig. Paragraph 5 of patent specification 1 illustrates the presence of +2 or -2. Furthermore, it is shown in Fig. 4B It is impossible to calculate the count value without using the polarity of the last pulse, and the use of both the polarity of magnet 20 from the last time and the polarity of the last pulse is mandatory. Paragraphs 0104 and 0105 of patent document 1 describe how the polarity of the pulse voltage from the last time and the sensor element state from the last time are used.

[0073] In the rotational speed sensing device 100 of the present embodiment, the count value is calculated without using the polarity of the pulse from the last time, and therefore there is little reference information. If the count value has an absolute value of 2, it might be necessary to write to the memory unit 18 twice. In the rotational speed sensing device 100 of the present embodiment, the absolute value of the count value is 1, and thus the writing to the memory unit 18 is necessarily completed in one go.

[0074] Fig. Figure 5A shows the polarity of the pulse and the polarity of the magnet 20 in a case where the arrangement of the magnet wire 10 and the magnetic polarity determination unit 14 in patent specification 1 is the same as in Fig. 3A is. Fig. 5B shows a relationship between the polarity of the pulse, the polarity of magnet 20 and the count value of Fig. 5A.

[0075] In Fig. In 5A, the magnet wire 10 is arranged in a direction orthogonal to the tangent of the magnet 20, and the magnetic polarity determination unit 14 is arranged in a position 45 degrees from the magnet wire 10 about an axis of rotation. Fig. 5A and Fig. Detailed descriptions of the individual points are omitted in section 5B.

[0076] In Fig. 5B, there is 2 in the absolute value of the count. This is because the count in patent document 1 is calculated using the polarity of the pulse as a reference. In patent document 1, according to paragraphs 0099 and 0100, the count is +1 or -1 if the polarity of the pulse is different. The fact that the count changes means that the quadrant (segment) is changed. Therefore, in Fig. 5B, for example, defines a quadrant boundary between point c and point d, each exhibiting a different pulse polarity. Therefore, if the pulse at point d is generated after the pulse at point c, the count value is -1. Furthermore, if a pulse omission occurs at point d after the pulse at point c, and the next pulse is generated at point f, the count value is -2. Thus, the variations of the count value increase in four ways (0, -1, -2, +1), and both the polarity of the last pulse and the polarity of magnet 20 from the last time must be used to determine the count value.

[0077] In the present embodiment, the count value is calculated using the polarity of magnet 20 as a reference. That is, the absolute value of the count is 1 when the polarity of magnet 20 is changed, and the absolute value of the count is 0 when the polarity of magnet 20 is not changed. Therefore, if the pulse is generated at point d after the pulse has been generated at point c, the count value is 0 (see Fig. 3B). Furthermore, even if the pulse omission at point d is generated after the pulse at point c and the next pulse is generated at point f, the movement of the quadrant is one according to the change in polarity of magnet 20, and the count value is -1 (see Fig. 3B).

[0078] Fig. Figure 6A shows the polarity of the pulse and the polarity of the magnet 20 in a case where the arrangement of the magnet wire 10 and the magnetic polarity determination unit 14 is different in the example. Fig. Figure 6B shows the relationship between the polarity of the pulse, the polarity of magnet 20, and the count value in Fig. 6A. In Fig. 6A and Fig. Detailed descriptions of the individual points are also omitted in section 6B.

[0079] In Fig. 6A, since the magnet wire 10 is arranged in an orientation parallel to the tangent of the magnet 20, the pulse generation position is the same position as that of with Fig. 4A. Furthermore, the magnetic polarity determination unit 14 detects the polarity of the magnet 20 in a section relative to the magnet wire 10. It should be noted that in the present example, the count value is calculated using the polarity of the magnet 20 as a reference. Therefore, the method of subdividing the quadrants differs from that in Fig. 4A.

[0080] Out of Fig. 6B shows that in the present example, similar to that in Fig. 3B, the count value can be calculated without using the polarity of the pulse from the last time. Furthermore, the absolute value of the count value in the present example is 1. That is, regardless of the arrangement of the magnet wire 10 and the magnetic polarity determination unit 14, the effect described above can be achieved by calculating the count value using the polarity of the magnet 20 as a reference.

[0081] Fig. Figure 7 is a flowchart showing an example of a rotational speed detection method for a rotator 30. In the rotational speed detection method, the Fig. 1 to Fig. 3B, Fig. 6A or Fig. The count value described in 6B can be calculated. That is, in the rotational speed detection method, the count value can be calculated based on the polarity of magnet 20 from the last time, the polarity of the pulse from this time, and the polarity of magnet 20 from this time. Furthermore, in the rotational speed detection method, the count value can be calculated without using the polarity of the pulse from the last time. Fig. Number 7 is an example of this.

[0082] In step 1, the polarity of the pulse from magnet wire 10 is detected. The pulse can be a pulse from magnet wire 10 that is output depending on the change in the direction of the magnetic field exerted by the rotator 30, which is magnetized along the direction of rotation on four or more poles. In step 2, the polarity of magnet 20 is detected. The polarity of magnet 20 can be the polarity of magnet 20 of the rotator 30 at a predetermined relative position with respect to magnet wire 10. Steps 1 and 2 can be performed in the computation unit 16 of Fig. 1 will be carried out.

[0083] In step 3, the polarity of magnet 20 from the last time is read. In step 3, the processing unit 16 can read the polarity of magnet 20 from the last time from the storage unit 18. It should be noted that the order of steps 1 to 3 is sequential from the one in Fig. 7 may differ.

[0084] Step 4 determines whether the polarity of magnet 20 this time matches the polarity of magnet 20 last time. If the polarity of magnet 20 this time matches the polarity of magnet 20 last time (yes), the count value can be calculated, retaining the integrated count value. In this example, the procedure proceeds to step 6 to calculate the count value of 0.

[0085] If the polarity of magnet 20 this time and the polarity of magnet 20 last time do not match (No), the count value can be output, which decreases or increases the integrated value. In the present example, the procedure proceeds to step 5 to determine if the pulse polarity this time and the polarity of magnet 20 this time match. If the pulse polarity this time and the polarity of magnet 20 this time match (Yes), the count value of +1 is calculated in step 6. If the pulse polarity this time and the polarity of magnet 20 this time do not match (No), the count value of -1 is calculated in step 6. Steps 4 to 6 can be performed in computation unit 16.In other words, when the calculation unit 16 is triggered by the pulse to start calculating the count value, the calculation unit 16 detects, based on the polarity of the magnet 20 of the rotator 30 that was detected last time, the polarity of the pulse from that time, and the polarity of the magnet 20 of the rotator 30 at a time when the pulse from that time is generated, that another segment, which is adjacent to a segment that is opposite the magnet wire 14, at a placement position of the magnet wire 10 at a time of pulse generation from the last time, is moved so that it is opposite the placement position of the magnet wire 10 at a time of pulse generation from that time.More precisely, at a time of pulse generation of this time, the calculation unit 16 determines whether a segment opposite the placement position of the magnet wire 10 has reached its position by performing a rotation operation either clockwise or counterclockwise from the position it was in at the time of pulse generation of the last time, and calculates the count value according to the determination result.

[0086] In step 7, the calculated count value is integrated. The integration of the count value can be performed in memory unit 18 by outputting the count value calculated by computation unit 16 to memory unit 18. Furthermore, in step 7, the polarity of magnet 20 can be stored for this instance. Computation unit 16 can write the polarity of magnet 20 for this instance to memory unit 18. The polarity of the pulse cannot be stored for this instance in step 7.

[0087] Fig. Figure 8A shows the relative position of the magnetic polarity determination unit 14 relative to the magnet wire 10. The rotator 30 of the present example is magnetized at four poles. It should be noted that in Fig. Figure 8A shows only the interior of the rotator 30 and the magnet 20. The magnet wire 10 of the present example extends in a direction that intersects a tangent to the rotator 30 in the direction of rotation.

[0088] The magnetic polarity detection unit 14 of the present example is a magnetic sensor. The magnetic polarity detection unit 14 of the present example is arranged such that it does not face any boundary of the magnetization of the rotator 30 when the magnet wire 10 and the boundary of the magnetization of the rotator 30 are arranged in a position where they are opposite each other. Furthermore, in the present example, the boundary of the magnetization of the rotator 30 is the boundary between the first pole section 21 and the second pole section 22 of the magnet 20. Fig. Figure 8A shows a case in which the magnet wire 10 and the boundary of the rotator 30's magnetization are arranged at opposite positions. This reduces the false-positive rate of the magnetic polarity determination unit 14. "Not opposite the boundary" can mean that no boundary exists within a range of ±10 degrees around the magnetic polarity determination unit 14 in the direction of rotation. The boundaries of the first pole section 21 and the second pole section 22 can be arranged at equal angular intervals in the direction of rotation.

[0089] The magnetic polarity determination unit 14 can be positioned such that it is at its greatest distance from the boundary of the rotator 30's magnetization when the magnet wire 10 and the boundary of the rotator 30's magnetization are located at opposite positions. The distance from the boundary can be the distance from the boundary closest to the magnetic polarity determination unit 14. As long as the boundary is positioned at equal angular intervals, there will be two boundaries equidistant from the magnetic polarity determination unit 14. In the present example, the magnetic polarity determination unit 14 is positioned at a distance of either 45 degrees or 135 degrees from the magnet wire 10 about the rotation axis 32 of the rotator 30, and at this position, the distance from the boundary is greatest. In this way, the false-positive rate of the magnetic polarity determination unit 14 can be reduced.It should be noted that the arrangement or angle described above can have a width. The width can be ±10 degrees, ±5 degrees, or ±2 degrees.

[0090] Fig. Figure 8B is another figure that describes the relative position of the magnetic polarity determination unit 14 relative to the magnet wire 10. The rotator 30 of the present example is magnetized at six poles. It should be noted that in Fig. Figure 8B shows only the interior of the rotator 30 and the magnet 20. The boundary between the first pole section 21 and the second pole section 22 of this example is also arranged at the same angular distance in the direction of rotation. The magnet wire 10 of this example also extends in a direction that intersects a tangent to the rotator 30 in the direction of rotation. The magnetic polarity detection unit 14 of this example is also a magnetic sensor.

[0091] In the present example, if the magnet wire 10 and the limit of magnetization of the rotator 30 are positioned opposite each other, the position of the magnetic polarity detection unit 14 at which the distance from the limit of magnetization of the rotator 30 is greatest is a position of 30 degrees, 90 degrees, or 150 degrees from the magnet wire 10 around the rotation axis 32 of the rotator 30. The false positive rate of the magnetic polarity detection unit 14 can be reduced by positioning the magnetic polarity detection unit 14 at the position described above. The angle described above can have a width of ±5 degrees or ±2 degrees.

[0092] For the generalization of the arrangement described above, reference is made to the following. Described is an arrangement of the magnetic polarity determination unit 14 that has the greatest distance from the limit of magnetization of the rotator 30 when the magnet wire 10 and the limit of magnetization of the rotator 30 are arranged in opposite positions, in a case where the magnet wire 10 extends in a direction that intersects the tangent of the rotator 30 in the direction of rotation. The rotator is magnetized at the n pole. N is an even number. N can be an even number of 4 or more, an even number of 6 or more, or an even number of 8 or more. Furthermore, the limit of magnetization of the rotator 30 is arranged at an equal angular distance in the direction of rotation.

[0093] When the magnetic polarity determination unit 14 is at a position angle θ mThe distance from the boundary is greatest when the magnetic wire 10 is arranged around the rotation axis of the rotator 30. θm=180×m / n

[0094] It should be noted that m is any odd number less than n. The maximum value of the angle θ m The angle is 180 degrees. This means that the above expression can be used symmetrically clockwise or counterclockwise using the magnet wire 10 as a reference.

[0095] For example, if n = 4, the angle θ is m 45 degrees (m = 1) or 135 degrees (m = 3), to use the example in Fig. 8A to agree. The angle θ m can have a width. The width can be ±40 / n degrees, ±20 / n degrees, or ±8 / n degrees. Furthermore, the limit position of the magnetization of rotator 30 can also have a width similar to the angle θ. mexhibit. In this way, motion detection of the segment can be performed as described above by installing the magnet wire 10 and the magnetic polarity determination unit 14 and adjusting each segment to contain the boundary of the magnetization in a segment allocation for the rotator 30. This arrangement and segment allocation enable detection both when the segment change is generated for pulse generation and when the segment change is not generated. More precisely, if the pulse is generated when the boundary of the magnetization passes the position opposite the magnet wire 10 due to the rotation of the rotator 30, it can be detected that a segment is located at this position.Furthermore, the magnetic polarity determination unit 14, which is positioned at a relative position described above, determines the polarity of the magnet 20, which is located at a position opposite that relative position. It can then be determined that the segment opposite the magnet wire 10 is the same both last time and this time, as long as the polarity of the magnet 20 and the polarity of the magnet 20 at the time of the last measurement are the same. Furthermore, it can be determined that a segment change is generated as long as the polarity of the magnet 20 and the polarity of the magnet 20 at the time of the last measurement are different. Then, by combining this information with the polarity of the pulse, it can be determined that the segment change was caused by the rotational movement, either clockwise or counterclockwise.

[0096] Fig. Figure 9 is a perspective view showing an example of the arrangement of the magnet 20, the magnetic polarity detection unit 14, and the magnet wire 10. In the rotational speed detection system 200 described above, the magnet 20, the arrangement of the magnetic polarity detection unit 14, and the magnet wire 10 can be generalized as follows. That is, the rotational speed detection system 200 has a magnet 20 as a rotating magnet, which is magnetized along the direction of rotation at four or more poles. When the magnet 20 rotates, the magnet wire 10 outputs a pulse (voltage) with a polarity that depends on the change in one direction of a magnetic field generated by this rotation. The magnetic polarity detection unit 14 is positioned at a predetermined relative position to the magnet wire 10 and detects the polarity of the magnet 20 at its placement position.

[0097] In Fig. 9 is a direction parallel to the axis of rotation of the magnet 20 (a rotation axis direction), the Z-axis direction, and a longitudinal direction of the magnet wire 10, the X-axis direction. The magnet wire 10 can be arranged as follows. The magnet wire 10 can have one end 51 of the magnet wire 10 in a longitudinal direction that is arranged in an outer edge region 24 of the magnet 20, as seen from the rotation axis direction of the magnet 20. In Fig. Figure 9 shows a dotted line extending in the Z-axis direction from one end 51 of the magnet wire 10 to the outer edge region 24 of the magnet 20. Additionally, the magnet wire 10 can be extended in a direction orthogonal to the rotation axis of the magnet 20 (the X-axis direction in the Fig. 9) be arranged such that a midpoint 52 of a longitudinal axis of the magnet wire 10 is positioned further out than the outer edge end 25 of the magnet 20. In Fig. Figure 9 shows a dotted line extending outwards in the Z-axis direction from the center point 52 of the magnet wire 10 beyond the outer edge end 25 of the magnet 20. Additionally, with respect to the ring-shaped magnet 20, an end section of the magnet wire 10 (one end 51 in Fig. 9) be arranged such that it overlaps with an area occupied by the magnet 20, as seen from the direction of rotation of the magnet 20. In other words, the end section of the magnet wire 10 can be arranged such that it is located in a region between the inner diameter and the outer diameter of the magnet 20, as seen from the direction of rotation of the magnet 20. Furthermore, another end 53 of the magnet wire 10 can be arranged longitudinally such that it lies on a straight line passing through the axis of rotation of the magnet 20 and extending in the opposite direction to the axis of rotation. In other words, the axis of rotation of the magnet 20, one end 51 of the magnet wire 10, and the other end 53 of the magnet wire 10 can be arranged on a straight line, as seen from the direction of rotation of the magnet 20.Furthermore, the magnet wire 10 can be installed in the rotational direction of the magnet 20 in a space located above the top of the magnet 20 or below the bottom of the magnet 20. It should be noted that one end 51 and the other end 53 of the magnet wire 10 form a point in the middle of the end section of the magnet wire 10 in a direction perpendicular to the longitudinal direction of the magnet wire 10 (an axial direction). Fig. 9) may be.

[0098] The magnetic polarity determination unit 14 can be arranged as follows. The magnetic polarity determination unit 14 can be arranged such that it overlaps with the outer edge region 24 of the magnet 20, as seen from the rotational axis direction of the magnet 20. Fig. Figure 9 shows a dotted line extending in the Z-axis direction from the center of the magnetic polarity determination unit 14 to the outer edge region 24 of the magnet 20. Furthermore, the magnetic polarity determination unit 14 can be positioned relative to the ring-shaped magnet 20 such that it overlaps with a region occupied by the magnet 20, as viewed from the rotational axis of the magnet 20. In other words, the end section of the magnetic polarity determination unit 14 can be positioned in a region between the inner and outer diameters of the magnet 20, as viewed from the rotational axis of the magnet 20. Additionally, the magnetic polarity determination unit 14 can be integrated together with the computation unit 16 into an integrated circuit (IC chip).Furthermore, the magnetic polarity determination unit 14 can be positioned at 45 degrees or 135 degrees (each including an adjustment of ±10 degrees) from a line segment (corresponding to a reference line of the angle in . Fig. 8A) arranged in a direction connecting the axis of rotation to the central section of the magnet wire 10, as seen from the direction of rotation of the magnet 20. Furthermore, the magnetic polarity determination unit 14 can be installed in a space located above the top of the magnet 20 or below the bottom of the magnet 20, in the direction of rotation of the magnet 20. The magnetic polarity determination unit 14 can also be located in a space on the same side (a space closer to the positive side in the Z-axis than the magnet 20) with respect to the magnet wire 10 and in the direction of rotation of the magnet 20. Fig. 9) around the magnet 20 or in a space on the opposite side (a space that is closer to the negative side in the Z-axis direction than the magnet 20 in Fig. 9) be arranged.

[0099] The present invention has been described with reference to embodiments; however, the technical scope of the present invention is not limited to the embodiments described above. It is clear to those skilled in the art that various modifications or improvements can be made to the embodiments described above. It is also apparent from the description of the claims that embodiments with such modifications or improvements may be included within the technical scope of the present invention.

[0100] The operations, procedures, steps, and phases of each process performed by a device, system, flowchart, and method shown in the claims, embodiments, or diagrams may be performed in any order, as long as the order is not specified by "before," "previously," or the like, and as long as the output from a previous process is not used in a subsequent process. Even if the process flow is described in the claims, description, and drawings using terms such as "first" or "next," this does not necessarily mean that the process must be performed in that order. EXPLANATION OF THE REFERENCE SYMBOLS 10 magnet wire 11 first material 12 second material 14 Magnetic polarity determination unit 16 units of calculation 18 storage units 20 magnets 21 first polar section 22 second polar section 24 outer edge area 25 Outer edge end 30 Rotator 32 Rotation axis 34 Fastening section 40 support base 42 Support element 51 an end 52 Center 53 other ending 100 Rotational speed detection device 200 Rotational Speed ​​Detection System

Claims

[1] Rotational speed detection device comprising a magnet wire in which an alternating magnetic field with two or more cycles per revolution in an axial direction is provided corresponding to a rotational operation of a rotator, wherein the magnet wire outputs a pulse with a polarity that depends on a change in one direction of a magnetic field; a magnetic polarity determination unit that determines the polarity of a magnet forming the alternating magnetic field and contained in the rotator at a predetermined relative position with respect to the magnet wire; and a calculation unit that calculates a count value by counting a segment in a circumferential direction of the rotator, wherein The calculation unit calculates the count value based on a polarity of the rotator's magnet that was last detected, a polarity of the pulse from that time, and a polarity of the rotator's magnet at the time the pulse from that time is generated, and without using a polarity of the pulse from the last time. [2] Rotational speed detection device according to claim 1, wherein When the calculation unit is triggered by the pulse to start a calculation of the count value, the calculation unit, based on the polarity of the rotator's magnet last detected, the polarity of the pulse from that time, and the polarity of the rotator's magnet at the time the pulse is generated this time, detects that another segment adjacent to the segment opposite the magnet wire, at the time the pulse was last generated, is moved to a position opposite the magnet wire, at the time the pulse is generated this time. [3] Rotational speed detection device according to claim 2, comprising a storage unit which integrates the count value calculated by the computation unit in order to store the integrated count value as an integrated value. [4] Rotational speed detection device according to claim 3, wherein the calculation unit differentiates the count value for at least one polarity of the pulse from this time depending on whether the polarity of the magnet of the rotator from the last time and the polarity of the magnet of the rotator from this time are the same or not. [5] Rotational speed detection device according to claim 4, wherein the calculation unit outputs the count value, where the integrated value is retained, when the polarity of the magnet of the rotator from the last time matches the polarity of the magnet of the rotator this time, and The calculation unit outputs the count value at which the integrated value is decreased or increased if the polarity of the rotator's magnet differs from the previous time and the polarity of the rotator's magnet this time. [6] Rotational speed detection device according to claim 5, wherein the calculation unit distinguishes a sign of the count value depending on whether the polarity of the magnet of the rotator this time and the polarity of the pulse this time match or not. [7] Rotational speed detection device according to any one of claims 1 to 6, wherein the magnet wire is arranged such that it outputs the pulse when a limit of a magnetization of the rotator deviates from an opposite position. [8] Rotational speed detection device according to claim 7, wherein the magnetic wire extends in a direction that intersects a tangent to the rotator. [9] Rotational speed detection device according to any one of claims 1 to 6, wherein the magnetic polarity determination unit is a magnetic sensor and The magnetic sensor is arranged so that it does not face any limit of the rotator's magnetization, if the magnet wire and the limit of the rotator's magnetization are arranged in a position where they face each other. [10] Rotational speed detection device according to claim 9, wherein The magnetic sensor is arranged such that it has the greatest possible distance from the limit of magnetization of the rotator when the magnet wire and the limit of magnetization of the rotator are arranged in a position where they face each other. [11] Rotational speed detection device according to claim 10, wherein the rotator is magnetized on four poles. [12] Rotational speed detection device according to claim 11, wherein the magnetic sensor is arranged in a range of 45±10 degrees or 135±10 degrees from the magnet wire about a rotational axis of the rotator. [13] Rotational speed detection device according to claim 10, wherein the rotator is magnetized on n poles and the magnetic sensor within a range of ±40 / n degrees around any angle θ m is arranged at an angle from the magnet wire around a rotational axis of the rotator, wherein θm=±180×m / n, where m is any odd number smaller than n. [14] Rotational speed detection system comprising: the rotational speed detection device according to any one of claims 1 to 6; and the rotator. [15] Rotational speed calculation device which calculates a count value by counting a segment in a circumferential direction of a rotator based on an output of a magnet wire and a magnetic polarity determination unit, wherein the magnet wire is provided with an alternating magnetic field of two or more cycles per revolution in an axial direction corresponding to a rotational movement of the rotator and outputs a pulse with a polarity that depends on a change in one direction of a magnetic field; the magnetic polarity determination unit determines the polarity of a magnet that forms the alternating magnetic field and is contained in the rotator at a predetermined relative position with respect to the magnet wire; wherein The rotational speed calculation device calculates the count value based on a polarity of the rotator's magnet that was last detected, a polarity of the pulse from that time, and a polarity of the rotator's magnet at the time the pulse from that time is generated, and without using a polarity of the pulse from the last time.

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