Magnetic transmitter

Abstract

A magnetic encoder (100) includes a magnetic scaler (101) and a position detector (105) that move relative to each other. The magnetic scaler (101) includes a magnet group (102) in which at least three magnets with the same magnetization direction are arranged in an x-direction, and a magnet group (103) in which at least three magnets, each with an opposite magnetization direction, are arranged in the x-direction, with the magnet group (103) being adjacent to the magnet group (102) in the x-direction. The position detector (105) includes a magnetic sensor (106) that detects a magnetic field generated by the magnetic scaler (101). In the magnet group (102), the magnet widths increase from the ends to a center of the magnet group (102) and are each less than one magnetic slope. In the magnet group (103), the magnet widths increase from the ends towards a center of the magnet group (103) and are each smaller than the magnet slope.

Description

Area

[0001] The present disclosure relates to a magnetic encoder including a magnetic detector and a position detector that move relative to each other. background

[0002] A magnetic encoder includes a magnetic detector and a position detector that move relative to each other. Such a magnetic encoder is used as a rotary encoder, which is a rotary detector used to control a rotary servo motor, a linear encoder, which is a position detector used to control a linear motor, and the like.

[0003] Patent Literature 1 discloses a magnetic scaler with a plurality of magnetic poles. The magnetic scaler includes an array of magnetic poles, which are a plurality of magnetic poles of the same polarity spaced at equal intervals from each other. The spacing between the magnetic poles is greater than a width of the magnetic poles measured in an array direction and less than twice the width of the magnetic poles in the array direction. A magnetic sensor outputs varied magnetic fields of the magnetic scaler as an electrical signal, and position data is obtained from voltage peaks. List of citationsPatent literature

[0004] Patent Literature 1: Japanese Patent Application Laid-Open No. 2001-227904 Brief description of the inventionProblem to be solved by the invention

[0005] According to Patent Literature 1, widths with the same polarity of multiple magnets are all the same, which leads to a problem that only peak positions of the magnetic fields and the discrete position data corresponding to the peak positions are obtained.

[0006] The present disclosure has been developed in view of the foregoing, and an object of the present disclosure is to obtain a magnetic encoder capable of obtaining a smooth sine signal with a long period, thereby enabling the acquisition of continuous and highly accurate position data over a wide range. Ways to solve the problem

[0007] To solve the above-mentioned problem and achieve the object, a magnetic encoder according to the present disclosure includes a magnetic scaler and a position detector configured to move relative to each other. The magnetic scaler includes a first magnet group in which at least three magnets having an identical first magnetization direction are arranged in a first direction, and a second magnet group in which at least three magnets, each of which has a second magnetization direction opposite to the first magnetization direction, are arranged in the first direction. The second magnet group is adjacent to the first magnet group in the first direction. The position detector includes a magnetic sensor configured to detect a magnetic field generated by the magnetic scaler.In the first magnet group, magnet widths are configured to increase from the ends to a center of the first magnet group, and each of the magnet widths is smaller than a magnet pitch. In the second magnet group, magnet widths are configured to increase from the ends to a center of the second magnet group, and each of the magnet widths is smaller than the magnet pitch. Effect of the invention

[0008] The magnetic encoder according to the present disclosure is effective to obtain a smooth sine wave signal with a long period, thereby enabling the acquisition of continuous and highly accurate position data over a wide range. Short description of the drawings Fig. 1 is a perspective view of a magnetic encoder according to a first embodiment. Fig. 2 is a perspective view of the magnetic encoder according to the first embodiment, not illustrating an upper part of a main body. Fig. 3 is a front view of the magnetic encoder according to the first embodiment. Fig. 4 is an enlarged front view illustrating how magnets are arranged in magnet groups of the magnetic encoder according to the first embodiment. Fig. 5 is a front view of a magnetic scaler as a comparative example. Fig. 6 is a diagram illustrating a waveform of a magnetic flux density applied to a magnetic detection element by the magnetic scaler, which is the comparative example. Fig. 7 is a diagram illustrating a waveform of a magnetic flux density applied to magnetic sensors by a magnetic scaler of the magnetic encoder according to the first embodiment. Fig. 8 is a front view illustrating a configuration of a magnetic encoder according to a second embodiment. Fig. 9 is a diagram illustrating waveforms of a magnetic flux density applied to a magnetic sensor by a magnetic scaler of the magnetic encoder according to the second embodiment. Fig. 10 is an enlarged front view illustrating a configuration of a magnetic scaler of a magnetic encoder according to a third embodiment. Fig. 11 is an enlarged front view illustrating a configuration of a magnetic scaler of a magnetic encoder according to a fourth embodiment. Fig. 12 is a perspective view illustrating a configuration of a magnetic encoder according to a fifth embodiment. Description of embodiments

[0009] With reference to the drawings, a detailed description of magnetic encoders according to embodiments is provided below in this document. First embodiment.

[0010] Fig. 1 is a perspective view of a magnetic encoder according to a first embodiment. Fig. 2 is a perspective view of the magnetic encoder according to the first embodiment, not illustrating an upper part of a main body. Fig. 3 is a front view of the magnetic encoder according to the first embodiment. In Fig. In Figure 2, a portion of the base body 104 located above the magnet groups 102 and 103 is not illustrated to make it clearer how magnets are arranged.

[0011] The magnetic encoder 100 according to the first embodiment includes a magnetic scaler 101 and a position detector 105 that detects magnetic fields generated by the magnetic scaler 101. The magnetic encoder 100 according to the first embodiment is a linear encoder. The magnetic scaler 101 includes: the magnet group 102 as a first magnet group; the magnet group 103 as a second magnet group; and the base body 104, which is made of a non-magnetic material and holds the magnet groups 102 and 103 in place. The position detector 105 includes: a plurality of magnetic sensors 106 that detect the magnetic fields generated by the magnetic scaler 101; and a substrate 107 on which the magnetic sensors 106 are installed. Fig. 1 to 3 illustrate three-dimensional directions denoted by x, y, and z. The x-direction corresponds to a direction along which the magnetic scale 101 moves; the z-direction corresponds to a direction in which the position detector 105 faces the magnetic scale 101; and the y-direction is a direction perpendicular to the x-direction and the z-direction. In the present disclosure, in the case of the linear encoder, the x-direction corresponds to a first direction.

[0012] The magnetic scaler 101 and the position detector 105 move relative to each other. In the first embodiment, the magnetic scaler 101 is a motor that moves along the x-direction. The position detector 105 is a stator fixed at a given distance from the magnetic scaler 101 in the z-direction. The position detector 105 detects a position of the magnetic scaler 101 based on the magnetic fields that shift as the magnetic scaler 101 passes by.

[0013] Fig. Fig. 4 is an enlarged front view illustrating how magnets are arranged in magnet groups 102 and 103 of the magnetic encoder 100 according to the first embodiment. For the magnetic encoder 100 of the first embodiment shown in Figs. Fig. 1 to 4, a magnet width modulation method is used by which magnet widths Lm vary. The arrows in the magnets that are shown in the Fig. 3 and Fig. 4 indicate the internal magnetization directions after magnetization. Each of the arrows has a pointed end indicating a north pole and a base end indicating a south pole. Therefore, each magnet 10 in the magnet group 102 has the south pole on its side facing the position detector 105. Each magnet 10 in the magnet group 103 has the north pole on its side facing the position detector 105. The internal magnetization direction of each magnet will hereinafter be referred to simply as the magnetization direction. Thus, the magnets 10 constituting the magnet group 102 are all magnetized in a first magnetization direction, and the magnets 10 constituting the magnet group 103 are all magnetized in a second magnetization direction opposite to the first magnetization direction.

[0014] The magnet groups 102 and 103 have the same number of magnets 10, which is at least three. A magnet pitch Pm is constant. The magnet pitch Pm is a pitch at which the magnets 10 are arranged and refers to a distance between centerlines of any two magnets 10 adjacent in the x-direction. The magnet widths Lm increase and decrease according to a sine function, which refers to a sinusoidal function. In other words, the magnet widths Lm increase from the ends to a center of each of the magnet groups 102 and 103 with respect to the x-direction. In other words, the magnet widths Lm in each of the magnet groups 102 and 103 gradually increase and then gradually decrease. However, each of the magnet widths Lm is smaller than the magnet pitch Pm. In other words, even the largest magnet width Lm is smaller than the constant magnet pitch Pm.

[0015] As in Fig. As illustrated in Figure 4, the magnets 10 constituting the magnet group 102 are eight in number. The magnets 10 constituting the magnet group 103 are also eight in number. A total of sixteen magnets 10 are arranged at the same magnet pitch Pm. A position - Pm / 2 away in an x-direction from the magnet 10, which is installed furthest from the magnet group 103 among the magnets 10 constituting the magnet group 102, namely a left edge of the Fig. 4, corresponds to 0 degrees of the sine function. A position Pm / 2 away in the x-direction from the magnet 10 installed furthest from the magnet group 102 among the magnets 10 forming the magnet group 103, namely a right edge of the Fig. 4 illustrated magnetic scale 101, corresponds to 360 degrees of the sine function.

[0016] In Fig. 4, the eight magnets 10 in magnet group 102 are arranged at the magnet pitch Pm; this corresponds to arranging these magnets 10 at a pitch of 22.5 degrees, starting at 11.25 degrees of the sine function. The eight magnets in magnet group 102 correspond to a range from 0 degrees to 180 degrees of the sine function, and each of their respective magnet widths Lm is defined by a value obtained by multiplying an integral over a corresponding 22.5-degree subdivision (eight equal parts) of the sine function by a constant. The eight magnets 10 in magnet group 103 are similarly arranged at the magnet pitch Pm; this corresponds to arranging these magnets 10 at the pitch of 22.5 degrees, starting at 191.25 degrees of the sine function.The eight magnets 10 in magnet group 103 correspond to a range of 180 degrees to 360 degrees of the sine function, and each of their respective magnet widths Lm is defined by a value obtained by multiplying an integral over a corresponding 22.5-degree subdivision (eight equal parts) of the sine function by a constant. Thus, magnet groups 102 and 103 each have a length in the x-direction corresponding to half a wavelength of a desired sinusoidal waveform.

[0017] As in Fig. As illustrated in Figure 3, the plurality of magnetic sensors 106 of the position detector 105 are arranged on the substrate 107 at equal intervals in the x-direction. The spacing of the magnetic sensors 106 is set to be equal to or less than the wavelength of the sinusoidal waveform formed by the magnetic scaler 101 to prevent the generation of regions where position detection is not possible.

[0018] Fig. 5 is a front view of a magnetic scaler as a comparative example. Fig. Figure 6 is a diagram illustrating a waveform of a magnetic flux density applied by the magnetic scaler to a magnetic detection element, which is the comparative example. The magnetic scaler 108, which is the comparative example, has magnets 108a and 108b that are long in the x-direction without performing any modulation of the magnet width. Magnet 108a has a magnetization direction corresponding to the positive z-direction, and magnet 108b has a magnetization direction corresponding to the negative z-direction. Fig. 6, a vertical axis represents the magnetic flux density Bz and a horizontal axis represents a position of the magnetic scale 108. “au” stands for an arbitrary unit. In Fig. 6, a solid line represents the magnetic flux density obtained from the magnetic scaler as the comparative example, and a dashed line represents an ideal sinusoidal waveform. As in Fig. As illustrated in Figure 6, the ideal sinusoidal waveform cannot be obtained from the magnetic scaler 108, which is the comparative example. The same applies to arranging magnetic poles of equal strength, with the magnet width Lm and the magnet pitch Pm specified as in Patent Literature 1, in which case, a generated signal with a long period is not an ideal sinusoidal signal.

[0019] Fig. Fig. 7 is a diagram illustrating a waveform of a magnetic flux density applied to the magnetic sensors 106 by the magnetic scaler 101 of the magnetic encoder 100 according to the first embodiment. Fig. 7, a vertical axis represents the magnetic flux density Bz and a horizontal axis represents the position of the magnetic scale 101. In Fig. 7, a solid line represents the magnetic flux density obtained from the magnetic scaler 101, and a dashed line represents the ideal sinusoidal waveform. As in Fig. As illustrated in Fig. 7, the waveform reproducing the ideal sinusoidal wave is obtained from the magnetic scaler 101 according to the first embodiment.

[0020] For one cycle of the magnetic scaler 101, a signal must be generated as long as one cycle is required for an absolute position of the magnetic scaler 101 to be detected. With the magnet groups 102 and 103, the magnetic scaler 101 according to the first embodiment enables the generation of a sinusoidal signal as long as one cycle, thereby enabling the implementation of the magnetic encoder 100 capable of detecting the absolute position.

[0021] According to the first embodiment described above, since the magnet widths of magnet groups 102 and 103 are modulated to provide a single-cycle sinusoidal waveform, a smooth, long-period sinusoidal signal can be obtained, enabling the acquisition of continuous and highly accurate position data over a wide range. Since magnet groups 102 and 103 are arranged to generate the single-cycle sinusoidal waveform, the magnets have an increased total volume, resulting in enhanced magnetic fields and higher signal strength. Second embodiment.

[0022] Fig. 8 is a front view illustrating a configuration of a magnetic encoder 200 according to a second embodiment. The magnetic encoder 200 according to the second embodiment includes a magnetic scaler 201 and a position detector 205 that detects magnetic fields generated by the magnetic scaler 201. The magnetic encoder 200 according to the second embodiment is a linear encoder. In the second embodiment, the magnetic scaler 201 is a stator, and the position detector 205 is a driver.

[0023] The magnetic scaler 201 includes: a plurality of magnet groups 202 as first magnet groups; a plurality of magnet groups 203 as second magnet groups; and a base body 204 made of a non-magnetic material that holds the magnet groups 202 and 203 in place. Fig. In Figure 8, a portion of the base body 204 located beneath the magnet groups 202 and 203 is not illustrated to clarify how the magnets 20 are arranged. The position detector 205 includes a magnetic sensor 206 that detects the magnetic fields generated by the magnetic scaler 201; and a substrate 207 to which the magnetic sensor 206 is mounted.

[0024] In the magnetic scaler 201, the plurality of magnet groups 202 and the plurality of magnet groups 203 are arranged alternately in the x-direction. Each of the magnets 20 constituting the magnet groups 202 has a magnetization direction corresponding to the positive z-direction, and each of these magnets 20 constituting the magnet groups 203 has a magnetization direction corresponding to the negative z-direction. Each magnet group 202 and each magnet group 203 has the same number of magnets 20, which is at least three. A magnet pitch is constant for any adjacent magnets 20. Magnet widths increase and decrease according to a sine function. Each of the magnet widths is smaller than the magnet pitch.

[0025] In Fig. 8, the magnets 20 that form each magnet group 202 are four in number and correspond to a range of 0 degrees to 180 degrees of the sine function. Each magnet width in each magnet group 202 is defined by a value obtained by multiplying an integral over a corresponding 45-degree subdivision (four equal parts) of the sine function by a constant. The magnets 20 that form each magnet group 203 are four in number and correspond to a range of 180 degrees to 360 degrees of the sine function. Each magnet width in each magnet group 203 is defined by a value obtained by multiplying an integral over a corresponding 45-degree subdivision (four equal parts) of the sine function by a constant. The magnet widths increase from the ends to a center of each of the magnet groups 202 and 203 with respect to the x-direction.

[0026] Fig. 9 is a diagram illustrating waveforms of the magnetic flux density applied to the magnetic sensor 206 by the magnetic scaler 201 of the magnetic encoder 200 according to the second embodiment. Fig. 9, a vertical axis represents the magnetic flux density Bz and a horizontal axis represents a position of the magnetic scaler 201. Fig. 9 illustrates the magnetic flux density obtained from the magnetic scaler 201. The waveforms of the Fig. 9 corresponds to four cycles of the magnet groups 202 and 203. As in Fig. 9, the waveforms reproducing ideal sinusoidal waves are obtained from the magnetic scaler 201 according to the second embodiment.

[0027] According to the second embodiment described above, the plurality of magnet groups 202 and 203 are arranged in pairs, each generating a sinusoidal waveform with one cycle; therefore, sinusoidal signals with a long period can be obtained, enabling the acquisition of highly accurate absolute position data over a wider range. It is assumed that the magnetic scaler 201 of the second embodiment has the same length measured in the x-direction as the magnetic scaler 101 of the first embodiment. The magnetic scaler 201 covers multiple cycles of sinusoidal waveforms for the same scale length, thereby providing a sinusoidal signal with a short wavelength compared to the first embodiment. The shorter wavelength results in improved position detection accuracy and improved stability against output fluctuations.In addition, the position detection variation with the shorter wavelength is less significant and more stable in the presence of an output fluctuation corresponding to one degree of the sinusoidal signal. Third embodiment.

[0028] Fig. Fig. 10 is an enlarged front view illustrating a configuration of a magnetic scale 301 of a magnetic encoder according to a third embodiment. A position detector of the magnetic encoder according to the third embodiment is similar to the position detector 105 of the first embodiment shown in Figs. Fig. 1 to 3, and is not illustrated or described to omit redundancy. For the magnetic scaler 301 of the third embodiment, a magnetic pitch modulation method is used, by which the magnetic pitches vary. The magnetic encoder according to the third embodiment is a linear encoder. In the third embodiment, the magnetic scaler 301 is a driver, and the position detector, which is not illustrated, is a stator.

[0029] The magnetic scaler 301 includes: a magnet group 302 having a plurality of magnets 30 as a first magnet group; a magnet group 303 having a plurality of magnets 30 as a second magnet group; and a base body 304 made of a non-magnetic material that holds the magnet groups 302 and 303 in place. Fig. In Figure 10, a portion of the base body 304 located above the magnet groups 302 and 303 is not illustrated to clarify how the magnets 30 are arranged. Each magnet in the magnet group 302 has a magnetization direction corresponding to the positive z-direction, and each magnet in the magnet group 303 has a magnetization direction corresponding to the negative z-direction.

[0030] Magnet groups 302 and 303 have the same number of magnets 30, which is at least three. Each magnet 30 in magnet group 302 and each magnet 30 in magnet group 303 are set to a constant magnet width Lm.

[0031] In the third embodiment, the magnetic pitches Pm for the magnets constituting the magnet group 302 increase and decrease according to a sine function. The magnetic pitches Pm for the magnets 30 in the magnet group 302 are defined such that integrals of the sine function over the respective magnetic pitches Pm are equal. In other words, the magnetic pitches Pm for the magnets 30 with respect to the x-direction are set to decrease from the ends to a center of the magnet group 302, where the center corresponds to a maximum value of the sine function. In other words, the magnetic pitches Pm for the magnets 30 in the magnet group 302 gradually decrease and then gradually increase. The magnetic pitches Pm for the magnets 30 in the magnet group 303 are similarly defined such that integrals of the sine function over the respective magnetic pitches Pm are equal.In other words, the magnet pitches Pm for the magnets 30 are set to decrease from the ends to a center of the magnet group 303. The magnet width Lm for magnets is smaller than the magnet pitch Pm. In other words, each of the magnet pitches Pm is larger than the constant magnet width Lm.

[0032] According to the third embodiment described above, since the magnetic pitches of the magnet groups 302 and 303 are modulated to provide a single-cycle sinusoidal waveform, a smooth, long-period sinusoidal signal can be obtained, enabling the acquisition of continuous and highly accurate position data over a wide range. Since the magnet groups 302 and 303 are arranged to generate the single-cycle sinusoidal waveform, the magnets have an increased total volume, resulting in enhanced magnetic fields and higher signal strength. In addition, the implemented magnetic encoder is capable of absolute position detection. Fourth embodiment.

[0033] Fig. Fig. 11 is an enlarged front view illustrating a configuration of a magnetic scale 401 of a magnetic encoder according to a fourth embodiment. A position detector of the magnetic encoder according to the fourth embodiment is similar to the position detector 105 of the first embodiment shown in Figs. Fig. 1 to 3, and is not illustrated or described to omit redundancy. For the magnetic scaler 401 of the fourth embodiment, a magnet width and pitch modulation method is used, by which magnet widths and pitches vary. The magnetic encoder according to the fourth embodiment is a linear encoder. In the fourth embodiment, the magnetic scaler 401 is a driver, and the position detector, which is not illustrated, is a stator.

[0034] The magnetic scaler 401 includes: a magnet group 402 having a plurality of (twelve) magnets 40 as a first magnet group; a magnet group 403 having a plurality of (twelve) magnets 40 as a second magnet group; and a base body 404 made of a non-magnetic material that holds the magnet groups 402 and 403 in place. Fig. In Figure 11, a portion of the base body 404 located above the magnet groups 402 and 403 is not illustrated to clarify how the magnets 40 are arranged. Each magnet in the magnet group 402 has a magnetization direction corresponding to the positive z-direction; and each magnet in the magnet group 403 has a magnetization direction corresponding to the negative z-direction. The magnet groups 402 and 403 have the same number of magnets 40, which is at least three.

[0035] In the fourth embodiment, the magnet widths Lmn and the magnet pitches Pmn for the magnets 40 of the magnet groups 402 and 403 each increase and decrease according to a sine function. "n" is an integer from 0 to 11 inclusive. The "n"-th magnet width Lmn is smaller than the "n"-th magnet pitch Pmn. In other words, the magnet width Lmn is smaller than the corresponding magnet pitch Pmn.

[0036] When setting the magnet pitches Pmn for the magnets 40, the 0th magnet pitch Pm0 is set first, followed sequentially by the first magnet pitch Pm1, the second magnet pitch Pm2,..., and Pm11 according to the sine function. Pm1 to Pm11 are not illustrated in the drawing for simplicity. Each of the magnet widths Lmn is defined by a value obtained by multiplying an integral of the sine function over the corresponding magnet pitch Pmn by a constant. The magnet pitches Pmn for the magnets 40 are set to increase from ends to a center of each of the magnet groups 402 and 403 with respect to the x-direction, and the magnet widths Lmn are set to increase from the ends to the center.In other words, the magnet pitches Pmn for the magnets 40 in each of the magnet groups 402 and 403 gradually increase and then gradually decrease, and the magnet widths Lmn also gradually increase and then gradually decrease.

[0037] According to the fourth embodiment described above, since the magnetic pitches of the magnet groups 402 and 403 are modulated to provide a single-cycle sinusoidal waveform, a smooth, long-period sinusoidal signal can be obtained, enabling the acquisition of continuous and highly accurate position data over a wide range. Since the magnet groups 402 and 403 are arranged to generate the single-cycle sinusoidal waveform, the magnets have an increased total volume, resulting in enhanced magnetic fields and higher signal strength. In addition, the implemented magnetic encoder is capable of absolute position detection. Fifth embodiment.

[0038] Fig. 12 is a perspective view illustrating a configuration of a magnetic encoder according to a fifth embodiment. The magnetic encoder according to the fifth embodiment is a rotary encoder, and a magnetic width modulation method is applied similarly to the first embodiment. The magnetic encoder 500 according to the fifth embodiment includes: an annular magnetic scaler 501; and a magnetic sensor 505 that detects magnetic fields generated by the magnetic scaler 501. In the fifth embodiment, the magnetic scaler 501 is a driver, and the magnetic sensor 505 is a stator.

[0039] The magnetic scaler 501 includes: a magnet group 502 as a first magnet group, a magnet group 503 as a second magnet group; and a base body 504 made of a non-magnetic material that holds the magnet groups 502 and 503 in place. The magnetic scaler 501 is installed on a rotating shaft (not illustrated) and rotates. In the present disclosure, in the case of the rotary encoder, a circumferential direction, i.e., a rotation direction of the magnetic scaler 501, corresponds to the first direction. The magnetic sensor 505 is fixed on a substrate (not illustrated) at a given distance from the magnetic scaler 501 in the z-direction. The magnetic sensor 505 detects a position of the magnetic scaler 501 based on the magnetic fields that shift as the magnetic scaler 501 rotates.

[0040] The magnetic scaler 501 includes: the magnet group 502, which has a plurality of (sixteen) magnets 50 arranged in the circumferential direction; the magnet group 503, which has a plurality of (sixteen) magnets 50 arranged in the circumferential direction; and the base body 504, which is made of the non-magnetic material and holds the magnet groups 502 and 503 in place. Each magnet in the magnet group 502 has a magnetization direction pointing from its inner diameter side to its outer diameter side; and each magnet in the magnet group 503 has a magnetization direction pointing from its outer diameter side to its inner circumferential side. The magnet groups 502 and 503 have the same number of magnets 50, which is at least three.

[0041] A magnet pitch is constant for any adjacent magnets 50 in the magnet groups 502 and 503. In each of the magnet groups 502 and 503, magnet widths increase and decrease according to a sine function similar to the first embodiment. In other words, the magnet widths increase from the ends to a center of each of the magnet groups 502 and 503 with respect to the circumferential direction. In other words, the magnet widths in each of the magnet groups 502 and 503 gradually increase and then gradually decrease. However, each of the magnet widths is smaller than the magnet pitch. In other words, even the largest magnet width is smaller than the constant magnet pitch for the magnets 50.

[0042] It should be noted that the magnetic pitch modulation method shown in the third embodiment or the magnetic width and magnetic pitch modulation method shown in the fourth embodiment can be applied to the magnetic encoder according to the fifth embodiment.

[0043] According to the fifth embodiment, since the magnet widths of magnet groups 502 and 503 are modulated to provide a single-cycle sinusoidal waveform, a smooth, long-period sinusoidal signal can be obtained, enabling the implementation of a magnetic encoder capable of obtaining continuous and highly accurate position data over a wide range. Since magnet groups 502 and 503 are arranged to generate the single-cycle sinusoidal waveform, the magnets have an increased total volume, resulting in enhanced magnetic fields and higher signal strength. Additionally, the implemented magnetic encoder is capable of absolute position detection.

[0044] While the magnet widths or pitches vary to generate a sinusoidal magnetic field variation in the first to fifth embodiments, the magnetic forces of the magnets can vary with the magnet widths and pitches being uniform to generate a sinusoidal magnetic field variation. Methods for varying the magnetic forces include gradually changing the thickness of the magnets, gradually changing the distance from the magnetic sensor, gradually changing the magnetization rates of the magnets, and gradually changing the magnetic materials of the magnets.

[0045] In this document, the term “movement” includes both linear movement and rotational movement.

[0046] The above configurations illustrated in the embodiments are illustrative of contents of the present disclosure, may be combined with other publicly known techniques, and may be partially omitted or changed without departing from the gist of the present disclosure. List of reference symbols

[0047] 10, 20, 30, 40, 50, 108a, 108b magnet; 100, 200, 500 magnetic encoder; 101, 108, 201, 301, 401, 501 magnetic scaler; 102, 103, 202, 203, 302, 303, 402, 403, 502, 503 magnet group; 104, 204, 304, 404, 504 base body; 105, 205 position detector; 106, 206, 505 magnetic sensor; 107, 207 substrate; Lm, Lmn magnet width; Pm, Pm0, Pm1, Pm2, Pmn magnet pitch. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2001-227904

[0004]

Claims

[1] A magnetic encoder comprising a magnetic scaler and a position detector configured to move relative to each other, the magnetic scaler including: a first magnet group in which at least three magnets with an identical first magnetization direction are arranged in a first direction; and a second magnet group in which at least three magnets, each having a second magnetization direction opposite to the first magnetization direction, are arranged in the first direction, wherein the second magnet group is adjacent to the first magnet group in the first direction, wherein the position detector includes a magnetic sensor configured to detect a magnetic field generated by the magnetic scaler, wherein in the first magnet group, magnet widths are configured to increase from ends to a center of the first magnet group, and each of the magnet widths is smaller than a magnet pitch; and in the second magnet group, magnet widths are configured to increase from ends to a center of the second magnet group, and each of the magnet widths is smaller than the magnet pitch. [2] The magnetic encoder according to claim 1, wherein the first magnet group and the second magnet group of the magnetic scaler have the same magnet pitch, and the magnet widths of each of the first magnet group and the second magnet group are configured to vary according to a sine function. [3] A magnetic encoder comprising a magnetic scaler and a position detector configured to move relative to each other, the magnetic scaler including: a first magnet group in which at least three magnets with an identical first magnetization direction are arranged in a first direction; and a second magnet group in which at least three magnets, each having a second magnetization direction opposite to the first magnetization direction, are arranged in the first direction, wherein the second magnet group is adjacent to the first magnet group in the first direction, wherein the position detector includes a magnetic sensor configured to detect a magnetic field generated by the magnetic scaler, wherein in the first magnet group, magnet pitches are configured to decrease from ends to a center of the first magnet group, and each of the magnet pitches is greater than a magnet width; and in the second magnet group, magnet pitches are configured to decrease from ends to a center of the second magnet group, and each of the magnet pitches is greater than a magnet width. [4] The magnetic encoder according to claim 3, wherein the first magnet group and the second magnet group of the magnetic scaler have the same magnet width, and the magnet pitches of each of the first magnet group and the second magnet group vary according to a sine function. [5] A magnetic encoder comprising a magnetic scaler and a position detector configured to move relative to each other, the magnetic scaler including: a first magnet group in which at least three magnets with an identical first magnetization direction are arranged in a first direction; and a second magnet group in which at least three magnets, each having a second magnetization direction opposite to the first magnetization direction, are arranged in the first direction, wherein the second magnet group is adjacent to the first magnet group in the first direction, the position detector includes a magnetic sensor configured to detect a magnetic field generated by the magnetic scaler, wherein in the first magnet group, magnet widths are configured to increase from ends to a center of the first magnet group, and magnet pitches are configured to increase from the ends to the center, each of the magnet widths being smaller than a corresponding one of the magnet pitches; and in the second magnet group, magnet widths are configured to increase from ends to a center of the second magnet group, and magnet pitches are configured to increase from the ends to the center, wherein each of the magnet widths is smaller than a corresponding one of the magnet pitches. [6] A magnetic encoder according to claim 5, wherein the magnet widths and the magnet pitches of each of the first magnet group and the second magnet group of the magnetic scaler each vary according to a sine function. [7] A magnetic encoder according to any one of claims 1 to 6, wherein a length of the first magnet group in the first direction and a length of the second magnet group in the first direction correspond to half a wavelength of a sinusoidal waveform. [8] Magnetic encoder according to one of claims 1 to 7, wherein the magnetic scaler is arranged as a stator and the position detector is arranged as a drive and a plurality of the first magnet groups and a plurality of the second magnet groups are arranged in the first direction. [9] Magnetic encoder according to one of claims 1 to 7, wherein the position detector is arranged as a stator and the magnetic scale is arranged as a drive and a plurality of magnetic sensors are arranged in the first direction. [10] Magnetic encoder according to one of claims 1 to 9, wherein the magnetic encoder is a linear encoder. [11] Magnetic encoder according to one of claims 1 to 9, wherein the magnetic encoder is a rotary encoder.

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