Rotation detection device

Abstract

A rotation detecting device includes a detecting section and a signal processing section. The detecting section is configured to have a prescribed gap with respect to an outer peripheral section of a rotating body on which rotation position information is periodically set at certain intervals, to detect a change in magnetism received from the outer peripheral section due to a change in rotation position of the rotating body as the rotating body rotates, and to have a first magnetic element and a second magnetic element. When a certain interval is defined as a, the first magnetic element and the second magnetic element are disposed with a gap of a / 2 in the rotation direction of the rotating body. The first magnetic element outputs a first signal of the same period as the certain interval. The second magnetic element outputs a second signal of the same period as the first signal and in reverse phase. The signal processing section acquires a differential signal of the first signal and the second signal as rotation position information of the same period as the certain interval.

Description

[0001] This application is a divisional application of the invention patent application filed on December 19, 2019, with Chinese patent application number 201980088699.2 (international application number PCT / JP2019 / 049726) and entitled "Rotation Detection Device".

[0002] Cross-referencing of related applications

[0003] This application is based on Japanese Patent Application No. 2019-3975, filed on January 14, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0004] This disclosure relates to a rotation detection device. Background Technology

[0005] Conventionally, for example, Patent Document 1 discloses a rotation detection device that detects the rotation of a rotating body on its outer periphery, which periodically displays rotational position information at regular intervals. Specifically, the rotation detection device includes a detection unit that generates a main signal corresponding to the output of a plurality of magnetic detection elements that rotate with the rotating body, and a sub-signal having phase with the main signal.

[0006] Furthermore, the rotation detection device includes a determination circuit section that compares the main signal with a binarization threshold to generate a position signal obtained by binarizing the main signal, and compares the sub-signals with the binarization threshold to generate a phase signal obtained by binarizing the sub-signals. The determination circuit section sets the position signal as the rotational position information of the rotating body, and sets the phase signal as the rotation mode information of the rotating body.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent No. 6337842 Summary of the Invention

[0010] In recent years, in line with the desire for miniaturization and weight reduction of rotating bodies, the interval of rotational position information has become narrower. If the interval of rotational position information of a rotating body becomes narrower, the magnetic change received by the detection unit from the outer periphery of the rotating body becomes smaller. Therefore, the detection capability of the detection unit decreases.

[0011] Therefore, reducing the gap between the rotating body and the detection unit can be considered. However, to avoid the effects of vibration of the rotating body and vibration of the structure that fixes the rotating detection device, it is necessary to ensure the gap between the rotating body and the detection unit.

[0012] The purpose of this disclosure is to provide a rotation detection device that can ensure a detectable gap for the rotating body even if a certain interval of the rotation position information of the rotating body becomes narrower.

[0013] The rotation detection device disclosed herein includes a detection unit and a signal processing unit. The detection unit is configured with a predetermined gap relative to the outer periphery of a rotating body on which rotational position information is periodically provided at regular intervals. The detection unit detects changes in the magnetic field received from the outer periphery due to changes in the rotational position of the rotating body as it rotates. Based on the detection results from the detection unit, the signal processing unit obtains the rotational position information of the rotating body.

[0014] According to the first technical solution of this disclosure, the detection unit includes a first magnetic element and a second magnetic element. With a certain interval defined as 'a', the first magnetic element and the second magnetic element are configured to have a gap of a / 2 in the rotation direction of the rotating body. The first magnetic element outputs a first signal with the same period as the certain interval. The second magnetic element outputs a second signal that is inversely phase to the first signal and has the same period as the certain interval. The signal processing unit acquires the differential signal between the first signal and the second signal as rotational position information with the same period as the certain interval.

[0015] Therefore, since the first and second magnetic elements are configured with a spacing of a / 2, the first and second signals can be obtained as inverted signals. Thus, the amplitude of the differential signal between the first and second signals can be maximized. Therefore, even if the interval 'a' of the rotational position information of the rotating body becomes narrower, a detectable gap for the rotating body can be ensured.

[0016] According to the second technical solution of this disclosure, the detection unit includes a first magnetic element, a second magnetic element, and a third magnetic element. With a certain interval defined as 'a', the first and third magnetic elements are configured to have a interval of 'a' in the rotational direction of the rotating body. The first magnetic element outputs a first signal. The third magnetic element outputs a third signal that is in phase with the first signal.

[0017] The second magnetic element is positioned between the first and third magnetic elements in the rotational direction of the rotating body. The second magnetic element outputs a second signal that has phase with the first and third signals and has the same period as the rotational position information.

[0018] The signal processing unit obtains a differential signal between a first operational signal based on the second signal and having the same period as the second signal, and a second operational signal based on the first signal and the third signal and having phase relative to the first operational signal, as rotational position information with the same period as a certain interval.

[0019] Therefore, since the first and third magnetic elements are configured with a spacing of 'a', signals with the first and third signals as periods of 'a' can be obtained. That is, the amplitude of the second operational signal can be maximized. Thus, the difference between the first and second operational signals can be improved. That is, the amplitude of the differential signal can be ensured. Therefore, even if the interval 'a' of the rotational position information of the rotating body becomes narrower, a detectable gap for the rotating body can be ensured. Attached Figure Description

[0020] The above and other objects, features, and advantages of this disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings,

[0021] Figure 1 This is a diagram showing the configuration relationship between the rotation detection device and the gear in the first embodiment, as well as the various signals.

[0022] Figure 2 This is a diagram showing the circuit structure of the rotation detection device according to the first embodiment.

[0023] Figure 3 This is a diagram showing the configuration relationship of the rotary detection device and gear, and the signals, when the interval between the first magnetic detection element and the third magnetic detection element is smaller than a / 2, as a comparative example.

[0024] Figure 4 This is a diagram showing the configuration relationship between the rotation detection device and the gear in the second embodiment, as well as the various signals.

[0025] Figure 5 This is a diagram showing the circuit structure of the rotation detection device according to the second embodiment.

[0026] Figure 6 This is a diagram showing a modified example of the arrangement of the magnetic detection elements in the second embodiment.

[0027] Figure 7 This is a diagram showing a modified example of the arrangement of the magnetic detection elements in the second embodiment.

[0028] Figure 8 This is a diagram showing a modified example of the arrangement of the magnetic detection elements in the second embodiment.

[0029] Figure 9 This is a diagram showing a modified example of the arrangement of the magnetic detection elements in the second embodiment.

[0030] Figure 10 This is a diagram showing a modified example of the arrangement of the magnetic detection elements in the second embodiment.

[0031] Figure 11This is a diagram showing a modified example of the configuration of the bias magnet and sensor chip in relation to the second embodiment.

[0032] Figure 12 This is a diagram showing the configuration relationship between the rotation detection device and the gear in the third embodiment, as well as the various signals.

[0033] Figure 13 This is a diagram showing the arrangement of the magnetic detection elements in the fourth embodiment.

[0034] Figure 14 This is a diagram showing a modified example of the arrangement of the magnetic detection elements in the fourth embodiment.

[0035] Figure 15 This is a diagram showing the configuration relationship between the rotation detection device and the gear in the fifth embodiment, as well as the various signals.

[0036] Figure 16 This is a diagram showing the circuit structure of the rotation detection device according to the fifth embodiment.

[0037] Figure 17 This is a diagram showing the arrangement of the magnetic detection elements in the sixth embodiment.

[0038] Figure 18 This is a diagram showing a modified example of the arrangement of the magnetic detection elements in the sixth embodiment.

[0039] Figure 19 This is a diagram showing the configuration relationship between the rotation detection device and the magnetized rotor in the seventh embodiment, as well as the various signals.

[0040] Figure 20 This is a diagram showing a modified example of the rotation detection device according to the seventh embodiment.

[0041] Figure 21 This is a diagram showing a modified example of the rotation detection device according to the seventh embodiment.

[0042] Figure 22 This is a diagram showing the configuration relationship between the rotation detection device and the magnetized rotor in the eighth embodiment, as well as the various signals.

[0043] Figure 23 This is a diagram showing a modified example of the rotation detection device according to the eighth embodiment. Detailed Implementation

[0044] The following is a reference to the appendix. Figure 1The following describes various forms used to implement this disclosure. In each embodiment, there are instances where parts corresponding to items described in prior embodiments are given the same reference numerals, thus omitting repetitive descriptions. Even when only a portion of the structure is described in each embodiment, other previously described embodiments can be applied to the remaining parts of the structure. Not only are the combinations of combinable parts explicitly shown in each embodiment, but embodiments can also be partially combined with each other even without explicit description, provided that no particular obstacle arises in the combination.

[0045] (First Embodiment)

[0046] Hereinafter, the first embodiment will be described with reference to the accompanying drawings. The rotation detection device, for example, detects the rotation of a gear assembled in a vehicle's transmission. Figure 1 As shown, the rotation detection device 100 is arranged opposite to the outer periphery 201 of the gear 200. The gear 200 is a gear-shaped rotating body.

[0047] On the outer periphery 201 of the gear 200, protrusions 202 and recesses 203 are alternately arranged in the rotational direction. The protrusions 202 are teeth. The protrusions 202 and recesses 203 indicate the rotational position information of the gear 200 in the rotational direction. The protrusions 202 and recesses 203 have a certain width in the rotational direction. The protrusions 202 and recesses 203 are periodically arranged at certain intervals in the rotational direction. Furthermore, in... Figure 1 A portion of the outer periphery 201 of the gear 200 is shown unfolded in a straight line.

[0048] Here, a certain interval is defined as 'a'. The certain interval 'a' is the gear pitch of gear 200. The gear pitch is the interval between protrusions 202. Specifically, the gear pitch is from the rising edge of the protrusion 202 in the rotational direction of gear 200 to the rising edge of the adjacent protrusion 202. Alternatively, the gear pitch is from a predetermined position of the protrusion 202 in the rotational direction of gear 200 to a position corresponding to the predetermined position in the adjacent protrusion 202. The predetermined position is, for example, the center position of the protrusion 202 in the rotational direction of gear 200. Alternatively, the gear pitch is from the falling edge of the protrusion 202 in the rotational direction of gear 200 to the falling edge of the adjacent protrusion 202.

[0049] That is, a certain interval 'a' is the repeated period of the rotational position of the gear 200 in the rotational direction. In other words, the rotational position information is periodically set at a certain interval 'a' on the outer periphery 201 of the gear 200.

[0050] The rotation detection device 100 includes a housing (not shown) formed by resin molding of a resin material such as PPS. The housing has a front end on the side of the gear 200, a fixing part that is fixed to a peripheral mechanism, and a connector part for connecting wiring (wire harness). A sensing detection part is provided inside the front end.

[0051] Furthermore, the housing is fixed to the peripheral mechanism via a flange portion with a predetermined gap between its front end and the protrusion 202 of the gear 200. Therefore, the gear 200 moves relative to the rotation detection device 100. The rotation detection device 100 includes a bias magnet 101 and a sensor chip 102 as sensing components.

[0052] The bias magnet 101 applies a bias magnetic field to the sensor chip 102, thereby increasing the detection sensitivity of the magnetic field of the sensor chip 102 by a certain amount. The bias magnet 101 is cylindrical. The sensor chip 102 is disposed in the hollow part of the bias magnet 101.

[0053] The sensor chip 102 is configured as a semiconductor chip. The sensor chip 102 includes a detection unit 103. The detection unit 103 employs a magnetic detection method using a magnetoresistive element. The detection unit 103 detects the magnetic changes received from the outer periphery 201 due to the change in the rotational position of the gear 200 as it rotates. Specifically, the detection unit 103 outputs a signal corresponding to the position of the protrusion or depression as the gear 200 rotates. The detection unit 103 is configured with a predetermined gap relative to the outer periphery 201 of the gear 200 in the gap direction. That is, the gap direction is the radial direction of the gear 200.

[0054] like Figure 1 and Figure 2 As shown, the detection unit 103 includes a first magnetic detection element 104, a second magnetic detection element 105, a third magnetic detection element 106, a first operational amplifier 107, a second operational amplifier 108, and a third operational amplifier 109.

[0055] Each magnetic sensing element 104 to 106 is configured as a pair of magnetoresistive elements whose resistance changes with the rotation of the gear 200. Each pair of magnetoresistive elements has two resistive sections.

[0056] The magnetoresistive element is disposed on one side 110 of the sensor chip 102. In addition, the case of being disposed on one side 110 of the sensor chip 102 includes not only the case of being disposed directly on one side 110 of the sensor chip 102, but also the case of being disposed on a protective film or the like formed on one side 110.

[0057] The magnetoresistive elements are configured as a half-bridge circuit. Specifically, such as... Figure 2As shown, the first magnetic detection element 104 consists of two resistive sections connected in series between the power supply (Vcc) and the ground potential (GND). The two resistive sections are magnetoresistive elements 111 and 112. The two resistive sections are formed in a predetermined wiring pattern. The two wiring patterns are, for example, formed as quadrilateral regions.

[0058] In this embodiment, the quadrilateral shape is a square. Of course, each magnetic detection element 104 to 106 can also be formed in a rectangular area, depending on the design. Furthermore, the shapes of the areas where each magnetic detection element 104 to 106 is formed can be the same or only one can be different.

[0059] The first magnetic detection element 104 detects the change in resistance value of each magnetoresistive element 111, 112 as it is affected by the magnetic field during the rotation of the gear 200. Furthermore, based on the change in resistance value, the first magnetic detection element 104 outputs the voltage at the midpoint 113 of each magnetoresistive element 111, 112 as the first detection signal A.

[0060] The second and third magnetic detection elements 105 and 106 have the same structure as the first magnetic detection element 104. The second magnetic detection element 105 consists of two magnetoresistive elements 114 and 115. The second magnetic detection element 105 outputs the voltage at the midpoint 116 of each magnetoresistive element 114 and 115 as the second detection signal B. The third magnetic detection element 106 consists of two magnetoresistive elements 117 and 118. The third magnetic detection element 106 outputs the voltage at the midpoint 119 of each magnetoresistive element 117 and 118 as the third detection signal C.

[0061] Operational amplifiers 1 to 3, 107 to 109, are differential amplifiers. The midpoint potential of the midpoint 113 of the first magnetic detection element 104 is defined as A, and the midpoint potential of the midpoint 116 of the second magnetic detection element 105 is defined as B. Operational amplifier 107 outputs A - B as the operational result. The midpoint potential of the midpoint 119 of the third magnetic detection element 106 is defined as C. Operational amplifier 108 outputs B - C as the operational result.

[0062] The third operational amplifier 109 receives A-B from the first operational amplifier 107 and B-C from the second operational amplifier 108. Furthermore, the third operational amplifier 109 performs the operation {-(A-B)-(B-C)} and outputs the result as the main signal S1 (=2B-A-C) to the signal processing unit 120.

[0063] The signal processing unit 120 is a circuit unit that obtains the rotational position information of the gear 200 based on the detection result of the detection unit 103. The signal processing unit 120 is formed on the sensor chip 102. The signal processing unit 120 may also be formed on other semiconductor chips not shown.

[0064] The signal processing unit 120 includes a threshold generation unit 121, a comparator 122, and a control unit 123. The threshold generation unit 121 is composed of two resistors 124 and 125 connected in series between the power supply (Vcc) and the ground potential (GND). The potential at the midpoint 126 of each resistor 124 and 125 is used as the binarization threshold. The binarization threshold is used to binarize the main signal S1.

[0065] The comparator 122 receives the main signal S1 from the third operational amplifier 109 of the detection unit 103. The comparator 122 receives a binarization threshold from the threshold generation unit 121. Furthermore, the comparator 122 compares the main signal S1 with the binarization threshold to generate a position signal after binarizing the main signal S1.

[0066] The control unit 123 is a control circuit that receives a position signal from the comparator 122 as rotational position information and performs prescribed signal processing. The control unit 123 outputs the position signal to an external device (not shown) via the output terminal 127 (Vout).

[0067] The above describes the overall structure of the rotation detection device 100 according to this embodiment. Furthermore, the rotation detection device 100 includes a power supply terminal 128 (Vcc) and a ground terminal 129 (GND) for connection to an external device. The rotation detection device 100 is powered from an external device via the power supply terminal 128 and the ground terminal 129.

[0068] Next, the configuration of the magnetic detection elements 104 to 106 in the sensor chip 102 will be described. First, as... Figure 1 As shown, in the gap direction, each magnetic detection element 104 to 106 is in the same position.

[0069] All magnetic detection elements 104 to 106 are located in the hollow portion of the bias magnet 101. When the rotation detection device 100 is not affected by the gear 200, a bias magnetic field along the central axis of the bias magnet 101 is applied to the second magnetic detection element 105. On the other hand, a bias magnetic field surrounding the ends of the bias magnet 101 is applied to the first magnetic detection element 104 and the third magnetic detection element 106.

[0070] Furthermore, the first magnetic detection element 104 and the third magnetic detection element 106 are configured to have a distance 'a' between them in the rotational direction of the gear 200. That is, the distance between the first magnetic detection element 104 and the third magnetic detection element 106 is the same as the gear tooth pitch.

[0071] The second magnetic detection element 105 is disposed between the first magnetic detection element 104 and the third magnetic detection element 106 in the rotational direction of the gear 200. In this embodiment, the second magnetic detection element 105 is disposed at a position between the first magnetic detection element 104 and the third magnetic detection element 106. Therefore, the interval between the first magnetic detection element 104 and the second magnetic detection element 105 is the same as the interval between the second magnetic detection element 105 and the third magnetic detection element 106.

[0072] The spacing between the magnetic detection elements 104 to 106 is based on the center position in the rotational direction of the gear 200. The center positions of the first magnetic detection element 104 and the third magnetic detection element 106 are spaced a. The center positions of the first magnetic detection element 104 and the second magnetic detection element 105 are spaced a / 2. The center positions of the second magnetic detection element 105 and the third magnetic detection element 106 are spaced a / 2. Therefore, even if the arrangement of the magnetic detection elements 104 to 106 is different, the spacing between them is clearly determined.

[0073] Furthermore, the spacing between the magnetic detection elements 104 to 106 is actually based on the center position of one side 110 of the sensor chip 102 in one direction. One direction is the direction of the tangent to the arc along the direction of rotation.

[0074] Next, the signals of each magnetic detection element 104 to 106 will be explained. First, the first magnetic detection element 104 outputs a first detection signal A with the same period as the rotational position information. The third magnetic detection element 106 is arranged at an interval 'a' relative to the first magnetic detection element 104 in the rotational direction of the gear 200. Therefore, the third magnetic detection element 106 outputs a third detection signal C that is in phase with the first detection signal A. The amplitudes of the first detection signal A and the third detection signal C reach their maximum values ​​at the falling edge of the protrusion 202. Furthermore, the amplitudes of the first detection signal A and the third detection signal C reach their minimum values ​​at the rising edge of the protrusion 202.

[0075] On the other hand, the second magnetic detection element 105 is positioned between the first magnetic detection element 104 and the third magnetic detection element 106 in the rotational direction of the gear 200. Therefore, the second magnetic detection element 105 outputs a second detection signal B that is out of phase with respect to the first detection signal A and the third detection signal C. The amplitude of the second detection signal B reaches its maximum value at the rising edge of the protrusion 202. Furthermore, the amplitude of the second detection signal B reaches its minimum value at the falling edge of the protrusion 202.

[0076] As described above, the detection unit 103 obtains the main signal S1 based on the first detection signal A, the second detection signal B, and the third detection signal C. The main signal S1 is S1 = 2B - A - C = 2B - (A + C). That is, the main signal S1 is the differential signal between the first operational signal and the second operational signal.

[0077] The first operational signal is a signal based on the second detection signal B and has the same period as the second detection signal B. The amplitude of the first operational signal is twice the amplitude of the second detection signal B. That is, the amplitude of the first operational signal is 2B.

[0078] The second operational signal is a signal based on the first detection signal A and the third detection signal C, and has phase relative to the first operational signal. The amplitude of the second operational signal is the sum of the amplitudes of the first detection signal A and the third detection signal C. That is, the amplitude of the second operational signal is A + C.

[0079] The second detection signal B, the first detection signal A, and the third detection signal C are signals with the same period and are out of phase. Therefore, the amplitude of the main signal S1 is the difference between the maximum amplitude of the second operational signal and the maximum amplitude obtained by adding the amplitudes of the first detection signal A and the third detection signal C. Thus, the amplitude of the main signal S1 can be maximized.

[0080] like Figure 1 As shown, the main signal S1, which serves as the differential signal, is a signal with the same period as a certain interval 'a' of the gear 200. Furthermore, the main signal S1 is a waveform signal corresponding to the uneven structure of the protrusion 202 and concave portion 203 of the gear 200. The main signal S1 has the largest amplitude at the concave portion 203, the protrusion 202, and the edge portion of the gear 200. That is, the main signal S1 is a signal representing the rotational position information of the gear 200.

[0081] The signal processing unit 120 performs binarization by comparing the main signal S1 with a binarization threshold. Furthermore, the control unit 123 performs signal processing on the binarized position signal and outputs it to an external device.

[0082] As a comparative example, such as Figure 3 As shown, there is a case where the interval between the first magnetic detection element 104 and the third magnetic detection element 106 is smaller than a / 2. In this case, the periods of the first detection signal A of the first magnetic detection element 104 and the third detection signal C of the third magnetic detection element 106 are nearly out of phase. Therefore, the amplitude of the second operational signal is A+C, but the two amplitudes cancel each other out. The amplitude of the second operational signal is smaller than the amplitude of the first operational signal.

[0083] As a result, if the difference between the first and second operational signals is calculated, the amplitude of the first operational signal is weakened by the amplitude of the second operational signal. Therefore, the amplitude of the main signal S1 is smaller than when the first magnetic detection element 104 and the third magnetic detection element 106 are arranged at an interval of a.

[0084] Compared to the comparative example, in this embodiment, the first magnetic detection element 104 and the third magnetic detection element 106 are arranged with a spacing of 'a'. This allows the first detection signal A and the third detection signal C to be obtained as signals with a period of 'a'. That is, the amplitude of the second operational signal can be maximized. Furthermore, the second magnetic detection element 105 is disposed between the first magnetic detection element 104 and the third magnetic detection element 106. This allows the first operational signal and the second operational signal to be in opposite phase. That is, the differential effect between the first operational signal and the second operational signal can be maximized. Therefore, even if the interval 'a' of the rotational position information on the gear 200 narrows, the amplitude of the main signal S1 can be maximized, thus ensuring a detectable gap relative to the gear 200.

[0085] Furthermore, the spacing between the first magnetic detection element 104 and the third magnetic detection element 106 is preferably exactly the same as a, but it can also be slightly different, as long as the desired effect is achieved. Similarly, the second magnetic detection element 105 is preferably positioned between the first magnetic detection element 104 and the third magnetic detection element 106, but as long as the desired effect is achieved, it can be positioned between the first magnetic detection element 104 and the third magnetic detection element 106.

[0086] As a variation, the second magnetic detection element 105 may not be located between the first magnetic detection element 104 and the third magnetic detection element 106. However, from the viewpoint of ensuring amplitude, the position of the second magnetic detection element 105 is preferably within the range where the effect can be obtained.

[0087] Furthermore, in this embodiment, the gear 200 corresponds to the rotating body. In this embodiment, the first magnetic detection element 104, the second magnetic detection element 105, and the third magnetic detection element 106 correspond to the first magnetic element, the second magnetic element, and the third magnetic element.

[0088] Furthermore, in this embodiment, the first detection signal A, the second detection signal B, and the third detection signal C correspond to the first signal, the second signal, and the third signal, respectively. The main signal S1 in this embodiment corresponds to the differential signal.

[0089] (Second Implementation)

[0090] In this embodiment, the differences from the first embodiment will be mainly described. For example... Figure 4As shown, the detection unit 103 also has a fourth magnetic detection element 130 and a fifth magnetic detection element 131. The structure of the fourth magnetic detection element 130 and the fifth magnetic detection element 131 is the same as that of each magnetic detection element 104 to 106, and they are configured as a pair of magnetoresistive elements.

[0091] The fourth magnetic detection element 130 and the fifth magnetic detection element 131 are arranged between the first magnetic detection element 104 and the third magnetic detection element 106 in the rotational direction of the gear 200. The fourth magnetic detection element 130 and the fifth magnetic detection element 131 are formed in a square area on one side 110 of the sensor chip 102. Alternatively, the fourth magnetic detection element 130 and the fifth magnetic detection element 131 may be formed in a rectangular area depending on the design. Furthermore, the shape of the area forming the fourth magnetic detection element 130 and the fifth magnetic detection element 131 may be the same as or different from the others.

[0092] Furthermore, the fourth magnetic detection element 130 and the fifth magnetic detection element 131 are arranged with a distance of a / 2 in the rotational direction of the gear 200. Specifically, the center positions of the fourth magnetic detection element 130 and the fifth magnetic detection element 131 in the rotational direction of the gear 200 are arranged with a distance of a / 2.

[0093] The fourth magnetic detection element 130 and the fifth magnetic detection element 131 are arranged in the same position in the gap direction as the first magnetic detection element 104, the second magnetic detection element 105 and the third magnetic detection element 106.

[0094] The second magnetic detection element 105 is disposed between the fourth magnetic detection element 130 and the fifth magnetic detection element 131 in the rotational direction of the gear 200. Thus, the fourth magnetic detection element 130 is disposed between the first magnetic detection element 104 and the second magnetic detection element 105. The fifth magnetic detection element 131 is disposed between the second magnetic detection element 105 and the third magnetic detection element 106.

[0095] like Figure 5 As shown, the fourth magnetic detection element 130 consists of two magnetoresistive elements 132 and 133. The voltage at the midpoint 134 of each magnetoresistive element 132 and 133 is output as the fourth detection signal L. The fifth magnetic detection element 131 consists of two magnetoresistive elements 135 and 136. The fifth magnetic detection element 131 outputs the voltage at the midpoint 137 of each magnetoresistive element 135 and 136 as the fifth detection signal R.

[0096] The detection unit 103 also includes a fourth operational amplifier 138. The fourth operational amplifier 138 is a differential amplifier. The midpoint potential of the midpoint 134 of the fourth magnetic detection element 130 is defined as L, and the midpoint potential of the midpoint 137 of the fifth magnetic detection element 131 is defined as R. The fourth operational amplifier 138 calculates (L-R) and outputs the result as S2. Signal S2 is a sub-signal of a waveform that has a phase difference relative to the main signal S1. For example, sub-signal S2 is a waveform whose amplitude is maximum at the center of rotation of the convex portion 202 of the gear 200 and minimum at the center of rotation of the concave portion 203.

[0097] The comparator 122 shown in the first embodiment is referred to as the first comparator 122. The signal processing unit 120 also includes a second comparator 139. The second comparator 139 receives the sub-signal S2 from the fourth operational amplifier 138 of the detection unit 103 and receives a binarization threshold from the threshold generation unit 121. The second comparator 139 compares the sub-signal S2 with the binarization threshold to generate a phase signal after binarizing the sub-signal S2.

[0098] The control unit 123 receives a position signal from the first comparator 122 as rotational position information. Furthermore, the control unit 123 receives a phase signal from the second comparator 139 as rotation mode information for the gear 200. The rotation mode information indicates whether the gear 200 rotates clockwise or counterclockwise.

[0099] The control unit 123 determines whether the rotation direction of the gear 200 is clockwise or counterclockwise based on the rotational position information and rotation mode information. The control unit 123 outputs the position signal and the rotation direction information of the gear 200 to an external device (not shown) via the output terminal 127 (Vout).

[0100] Next, the signals of the fourth magnetic detection element 130 and the fifth magnetic detection element 131 will be explained. First, as... Figure 4 As shown, the fourth magnetic detection element 130 outputs a fourth detection signal L with the same period at a certain interval. The amplitude of the fourth detection signal L is at its maximum at the center of the width of the protrusion 202 in the rotational direction of the gear 200. Furthermore, the amplitude of the fourth detection signal L is at its minimum at the center of the width of the recess 203 in the rotational direction of the gear 200.

[0101] The fifth magnetic detection element 131 is arranged with an interval of a / 2 relative to the fourth magnetic detection element 130 in the rotational direction of the gear 200. Therefore, the fifth magnetic detection element 131 outputs a fifth detection signal R that is inversely phase to the fourth detection signal L and has the same period at a certain interval. That is, the amplitude of the fifth detection signal R is at its maximum value at the center of the width of the recess 203 in the rotational direction of the gear 200. Furthermore, the amplitude of the fifth detection signal R is at its minimum value at the center of the width of the protrusion 202 in the rotational direction of the gear 200.

[0102] As described above, the detection unit 103 obtains the sub-signal S2 based on the fourth detection signal L and the fifth detection signal R. The sub-signal S2 is S2 = L - R. That is, the sub-signal S2 is the differential signal between the fourth detection signal L and the fifth detection signal R. This differential signal is a signal that has phase relative to the main signal S1.

[0103] Therefore, based on the detection results of the fourth magnetic detection element 130 and the fifth magnetic detection element 131, the control unit 123 obtains a sub-signal S2 that has a phase relative to the main signal S1 as information on the rotation mode of the gear 200.

[0104] Next, the determination of the rotation direction of gear 200 will be explained. As described above, the signal processing unit 120 acquires the position signal after binarizing the main signal S1. The position signal is represented as Hi when the signal amplitude of the main signal S1 is greater than the binarization threshold, for example, and as Lo when the signal amplitude of the main signal S1 is less than the binarization threshold.

[0105] Furthermore, the signal processing unit 120 acquires the phase signal after binarizing the sub-signal S2. The phase signal is represented, for example, Hi, when the amplitude of the sub-signal S2 is greater than the binarization threshold, and for example, Lo, when the amplitude of the sub-signal S2 is smaller than the binarization threshold.

[0106] As the gear 200 rotates, a main signal S1, a sub-signal S2, a position signal, and a phase signal are generated. The position signal and phase signal are input to the control unit 123. Furthermore, the control unit 123 determines whether the rotation direction of the gear 200 is clockwise or counterclockwise based on the position signal and phase signal. That is, the signal processing unit 120 determines the rotation direction of the gear 200 based on the rotational position information and rotation mode information.

[0107] Specifically, when the gear 200 rotates in the forward direction, the amplitude of the main signal S1 is greater than the binarization threshold around time T1. Therefore, the position signal changes from Lo to Hi. Furthermore, since the amplitude of the sub-signal S2 is greater than the binarization threshold, the binarized phase signal becomes Hi. Thus, since both the position signal rising from Lo to Hi and the phase signal being Hi are satisfied, the control unit 123 determines that the gear 200 is rotating forward. The signal processing unit 120 outputs the rotation mode signal decreasing at time T1 as a signal indicating forward rotation to an external device.

[0108] On the other hand, when the rotation direction of gear 200 is reversed, around time T1, the amplitude of the main signal S1 becomes smaller than the binarization threshold. Therefore, the position signal changes from Hi to Lo. Furthermore, since the amplitude of the sub-signal S2 is larger than the binarization threshold, the binarized phase signal becomes Hi. Thus, since both the position signal decreasing from Hi to Lo and the phase signal being Hi are satisfied, the control unit 123 determines that gear 200 is rotating in reverse. The signal processing unit 120 outputs the rotation mode signal, which decreases at time T1 and has a pulse width larger than in the case of forward rotation, as a signal indicating reverse rotation to an external device. The above determination is the same at other time points such as time T2.

[0109] As explained above, the detection unit 103 includes five elements 104-106, 130, and 131. Furthermore, since the fourth magnetic detection element 130 and the fifth magnetic detection element 131 are arranged with a spacing of a / 2, the fourth detection signal L and the fifth detection signal R can be obtained as inverted signals. Therefore, the amplitude of the differential signal, i.e., the sub-signal S2, between the fourth detection signal L and the fifth detection signal R can be maximized. Thus, even if the interval a of the rotational position information in the gear 200 becomes narrower, the amplitude of the sub-signal S2 can still be maximized, thereby improving the accuracy of determining the rotational direction of the gear 200.

[0110] As a variation, the five elements 104-106, 130, and 131 can also be configured to correspond to the magnetic field generated by the bias magnet 101. For example, Figure 6 As shown, with the entire sensor chip 102 located within the hollow portion of the bias magnet 101, five elements 104-106, 130, and 131 are arranged along one of the concave magnetic force contour lines. The first magnetic detection element 104, the third magnetic detection element 106, the fourth magnetic detection element 130, the fifth magnetic detection element 131, and the second magnetic detection element 105 are located inside the hollow portion in the following order: Figure 6 Because the sensor chip 102 is located in the hollow part of the bias magnet 101, the configuration has the advantage of being more resistant to interference.

[0111] In addition, such as Figure 7 As shown, with the sensor chip 102 entirely outside the hollow portion of the bias magnet 101, five elements 104-106, 130, and 131 are arranged along one of the convex magnetic force contour lines. They are positioned away from the bias magnet 101 in the order of the first magnetic detection element 104, the third magnetic detection element 106, the fourth magnetic detection element 130, the fifth magnetic detection element 131, and the second magnetic detection element 105. Figure 7 Because the sensor chip 102 is closer to the gear 200 than the bias magnet 101, the configuration can increase the amplitude of the signal vibration.

[0112] As a variation, it can also be as follows: Figure 8 As indicated in the diagram, the five elements 104-106, 130, and 131 are arranged in a W-shape. That is, the first magnetic detection element 104, the second magnetic detection element 105, and the third magnetic detection element 106 are arranged on the side closer to the gear 200 than the fourth magnetic detection element 130 and the fifth magnetic detection element 131.

[0113] Or, it can be like Figure 9 As shown, the five elements 104 to 106, 130, and 131 are arranged in an M-shape. That is, the second magnetic detection element 105, the fourth magnetic detection element 130, and the fifth magnetic detection element 131 are arranged on the side closer to the gear 200 than the first magnetic detection element 104 and the third magnetic detection element 106. Figure 8 and Figure 9 The configuration is effective when the first magnetic detection element 104 and the third magnetic detection element 106 cannot ensure the interval of a.

[0114] As a variation, such as Figure 10 As shown, the second magnetic detection element 105 can also be positioned further from the outer periphery 201 of the gear 200 than the first magnetic detection element 104, the third magnetic detection element 106, the fourth magnetic detection element 130, and the fifth magnetic detection element 131. The first magnetic detection element 104, the third magnetic detection element 106, the fourth magnetic detection element 130, and the fifth magnetic detection element 131 are positioned at the same location in the clearance direction.

[0115] As a variation, it can also be like... Figure 11 As shown, a portion of the sensor chip 102 is located within the hollow portion of the bias magnet 101. In this case, the portion of the sensor chip 102 containing the five elements 104-106, 130, and 131 is located outside the hollow portion of the bias magnet 101. Figure 11The configuration can increase the amplitude of the signal vibration and ensure tolerance to interference.

[0116] Furthermore, in this embodiment, the fourth magnetic detection element 130 and the fifth magnetic detection element 131 correspond to the fourth magnetic element and the fifth magnetic element, respectively. In this embodiment, the fourth detection signal L and the fifth detection signal R correspond to the fourth signal and the fifth signal, respectively. In this embodiment, the sub-signal S2 corresponds to a signal that has phase relative to the differential signal.

[0117] (Third Implementation)

[0118] In this embodiment, the differences from the first and second embodiments will be mainly described. For example... Figure 12 As shown, the detection unit 103 employs a magnetic detection method using Hall elements. Therefore, the five elements 104-106, 130, and 131 are configured as Hall elements.

[0119] The bias magnet 101 has a cylindrical shape. In this embodiment, the N pole of the bias magnet 101 is located on the gear 200. The sensor chip 102 is disposed above the end face of the bias magnet 101 with one side 110 facing the gear 200. When the gear 200 rotates, the detection signal becomes maximum, corresponding to the positions of the elements 104-106, 130, and 131.

[0120] In this embodiment, the signal processing unit 120 acquires the differential signal of the fourth detection signal L and the fifth detection signal R as the main signal S3 (=L-R). The amplitude of the fourth detection signal L reaches its maximum value at the rising edge of the protrusion 202 of the gear 200. Furthermore, the amplitude of the fourth detection signal L reaches its minimum value at the falling edge of the protrusion 202. The amplitude of the fifth detection signal R is out of phase with the amplitude of the fourth detection signal L. In addition, the signal processing unit 120 acquires the sub-signal S4 (=2B-A-C) based on the first detection signal A, the second detection signal B, and the third detection signal C.

[0121] The processing of position and phase signals by the control unit 123, and the processing of determining the rotation direction of the gear 200, are the same as in the second embodiment. Furthermore, the same effects as in the first and second embodiments can be obtained. As described above, when using a Hall element, the rotational position and rotation direction of the gear 200 can also be obtained.

[0122] Furthermore, in this embodiment, the main signal S3 corresponds to the differential signal. In this embodiment, the sub-signal S4 corresponds to a signal that has phase relative to the differential signal.

[0123] (Fourth implementation)

[0124] In this embodiment, the differences from the first and second embodiments will be mainly described. For example... Figure 13 As shown, the detection unit 103 includes a first magnetic detection element 104, a second magnetic detection element 105, a third magnetic detection element 106, and a fifth magnetic detection element 131. The fifth magnetic detection element 131 is arranged between the second magnetic detection element 105 and the third magnetic detection element 106 in the rotational direction of the gear 200. That is, the detection unit 103 has four elements.

[0125] Similar to the first embodiment, the signal processing unit 120 acquires the main signal S5 (=2B-A-C). Furthermore, based on the detection results of the first magnetic detection element 104 and the fifth magnetic detection element 131, the signal processing unit 120 acquires a sub-signal S6, which has a phase relative to the main signal S5, as rotation mode information of the gear 200. The sub-signal S6 is S6=A-R. That is, the sub-signal S6 is the differential signal of the first detection signal A and the fifth detection signal R.

[0126] The processing of position and phase signals by the control unit 123, and the processing of determining the rotation direction of the gear 200, are the same as in the second embodiment. Furthermore, the same effects as in the first and second embodiments can be obtained. As described above, the rotational position and rotation direction of the gear 200 can be obtained using four components.

[0127] As a variation, such as Figure 14 As shown, the detection unit 103 may also have a fourth magnetic detection element 130 instead of a fifth magnetic detection element 131. The fourth magnetic detection element 130 is disposed between the first magnetic detection element 104 and the second magnetic detection element 105 in the rotational direction of the gear 200.

[0128] In this case, the signal processing unit 120 acquires the main signal S7 (=2B-A-C) in the same manner as described above. Furthermore, based on the detection results of the third magnetic detection element 106 and the fourth magnetic detection element 130, the signal processing unit 120 acquires L-C as the sub-signal S8. That is, the sub-signal S8 is the differential signal between the fourth detection signal L and the third detection signal C. Thus, the fourth magnetic detection element 130 can also be used.

[0129] Furthermore, in this embodiment, the fifth magnetic detection element 131 corresponds to the fourth magnetic element. The main signals S5 and S7 in this embodiment correspond to the differential signal. The sub-signals S6 and S8 in this embodiment correspond to signals that have phase relative to the differential signal.

[0130] (Fifth Embodiment)

[0131] In this embodiment, the differences from embodiments 1 to 4 will be mainly described. In this embodiment, the rotation detection device 100 uses two elements to detect the rotational position of the gear 200. Therefore, as Figure 15 and Figure 16As shown, the detection unit 103 has a fourth magnetic detection element 130 and a fifth magnetic detection element 131. The configuration and signals of the fourth magnetic detection element 130 and the fifth magnetic detection element 131 are the same as in the second embodiment.

[0132] The signal processing unit 120 acquires the main signal S9 (=L-R) of the fourth detection signal L and the fifth detection signal R as rotational position information with the same period at a certain interval. That is, the second comparator 139 receives the main signal S9 from the fourth operational amplifier 138 of the detection unit 103 and receives a binarization threshold from the threshold generation unit 121. The second comparator 139 compares the main signal S9 with the binarization threshold to generate a position signal after binarizing the main signal S9.

[0133] Based on the above structure, since the fourth magnetic detection element 130 and the fifth magnetic detection element 131 are arranged with a spacing of a / 2, the fourth detection signal L and the fifth detection signal R can be obtained as inverted signals. Therefore, the amplitude of the main signal S9 of the fourth detection signal L and the fifth detection signal R can be maximized. Thus, even if the certain interval a of the rotational position information in the gear 200 becomes narrower, the detectable gap of the gear 200 can be ensured.

[0134] Furthermore, in the detection unit 103, only two power-supplying components are needed. This reduces the power consumption of the rotation detection device 100.

[0135] Furthermore, in this embodiment, the fourth magnetic detection element 130 corresponds to the first magnetic element. In this embodiment, the fifth magnetic detection element 131 corresponds to the second magnetic element. In this embodiment, the fourth detection signal L and the fifth detection signal R correspond to the first signal and the second signal, respectively. In this embodiment, the main signal S9 corresponds to the differential signal.

[0136] (Sixth Embodiment)

[0137] In this embodiment, the differences from the fifth embodiment will be mainly described. For example... Figure 17 As shown, the detection unit 103 includes a first magnetic detection element 104, a second magnetic detection element 105, a fourth magnetic detection element 130, and a fifth magnetic detection element 131. The fourth magnetic detection element 130 is disposed between the first magnetic detection element 104 and the second magnetic detection element 105 in the rotational direction of the gear 200. That is, the detection unit 103 has four elements.

[0138] The signal processing unit 120 obtains a main signal S10 (=2B-A-R) based on the detection results of the first magnetic detection element 104, the second magnetic detection element 105, and the fifth magnetic detection element 131. Furthermore, based on the detection results of the fourth magnetic detection element 130 and the fifth magnetic detection element 131, the signal processing unit 120 obtains a sub-signal S11, which has a phase relative to the main signal S10, as information about the rotation mode of the gear 200. The sub-signal S11 is S11=L-R. That is, the sub-signal S11 is the differential signal between the fourth detection signal L and the fifth detection signal R.

[0139] The processing of position and phase signals by the control unit 123, as well as the processing of determining the rotation direction of the gear 200, are the same as in the second embodiment. Furthermore, the same effects as in the first and second embodiments can be obtained. As described above, the rotational position and rotation direction of the gear 200 can be obtained using four components. Alternatively, S11 can be used as the main signal, and S10 as the sub-signal.

[0140] As a variation, such as Figure 18 As shown, the detection unit 103 may also have a second magnetic detection element 105 and a third magnetic detection element 106. The fifth magnetic detection element 131 is disposed between the second magnetic detection element 105 and the third magnetic detection element 106 in the rotational direction of the gear 200.

[0141] In this case, the signal processing unit 120 obtains the main signal S12 (=2B-L-C) based on the detection results of the second magnetic detection element 105, the third magnetic detection element 106, and the fourth magnetic detection element 130. Furthermore, the signal processing unit 120 obtains L-R as a sub-signal S13 based on the detection results of the fourth magnetic detection element 130 and the fifth magnetic detection element 131. That is, the sub-signal S13 is the differential signal between the fourth detection signal L and the fifth detection signal R. Thus, the second magnetic detection element 105 and the third magnetic detection element 106 can also be used. Alternatively, S13 can be used as the main signal, and S12 as the sub-signal.

[0142] Furthermore, in this embodiment, the first magnetic detection element 104 corresponds to the third magnetic element. In this embodiment, the second magnetic detection element 105 corresponds to either the third or fourth magnetic element. Additionally, in this embodiment, the third magnetic detection element 106 corresponds to the fourth magnetic element. In this embodiment, the main signals S10 and S12 correspond to signals having phase relative to the differential signal. When S11 and S13 of this embodiment are used as the main signals, the main signals S11 and S13 correspond to the differential signal.

[0143] (Seventh Embodiment)

[0144] This embodiment mainly describes the parts that differ from the embodiments described above. For example... Figure 19As shown, in this embodiment, the rotating body that is being detected is a magnetized rotor 204. The magnetized rotor 204 has a first magnetic pole 205 and a second magnetic pole 206. The first magnetic pole 205 is an N pole. The second magnetic pole 206 is a S pole. The magnetized rotor 204 is a circular plate-shaped rotating body that is alternately magnetized with N and S poles in the circumferential direction of the outer peripheral portion 207.

[0145] In addition, Figure 19 A portion of the outer periphery 201 of the magnetized rotor 204 is shown unfolded in a straight line. Alternatively, the first magnetic pole 205 may be the S pole and the second magnetic pole 206 may be the N pole.

[0146] The interval 'a' is the length along the rotation direction of the magnetized rotor 204 from the center position of the first magnetic pole 205 to the center position of the next first magnetic pole 205. Alternatively, the interval 'a' can be set as the length from the center position of the second magnetic pole 206 to the center position of the next second magnetic pole 206. Or, the interval 'a' can also be set as the length from the boundary between the first and second magnetic poles 205 to the boundary between the next first and second magnetic poles 205.

[0147] Therefore, the first magnetic detection element 104 and the third magnetic detection element 106 are arranged with a spacing of 'a'. Similarly, the fourth magnetic detection element 130 and the fifth magnetic detection element 131 are arranged with a spacing of 'a / 2'. The arrangement of each element 104 to 106, 130, and 131 is the same as in the second embodiment.

[0148] Alternatively, GMR (Giant Magneto Resistance) elements are used as elements 104–106, 130, and 131. Elements 104–106, 130, and 131 can also be TMR (Tunneling Magneto Resistance) elements or AMR (Anisotropic Magneto Resistance) elements.

[0149] The sensor chip 102 is entirely located outside the bias magnet 101. That is, the sensor chip 102 is located between the outer periphery 207 of the magnetized rotor 204 and the bias magnet 101. The N pole side of the bias magnet 101 faces the outer periphery 207 of the magnetized rotor 204. Alternatively, the S pole side of the bias magnet 101 may also face the outer periphery 207 of the magnetized rotor 204.

[0150] In the rotational direction of the magnetized rotor 204, the amplitudes of the first detection signal A and the third detection signal C reach their maximum values ​​at the boundary where they switch from the first magnetic pole 205 to the second magnetic pole 206. Furthermore, the amplitudes of the first detection signal A and the third detection signal C reach their minimum values ​​at the boundary where they switch from the second magnetic pole 206 to the first magnetic pole 205. The amplitude of the second detection signal B reaches its maximum value at the boundary where it switches from the second magnetic pole 206 to the first magnetic pole 205. Furthermore, the amplitude of the second detection signal B reaches its minimum value at the boundary where it switches from the first magnetic pole 205 to the second magnetic pole 206.

[0151] In the rotation direction of the magnetized rotor 204, the amplitude of the fourth detection signal L is at its maximum at the center of the width of the second magnetic pole 206. Furthermore, the amplitude of the fourth detection signal L is at its minimum at the center of the width of the first magnetic pole 205. The amplitude of the fifth detection signal R is at its maximum at the center of the width of the first magnetic pole 205. The amplitude of the fifth detection signal R is at its minimum at the center of the width of the second magnetic pole 206. Furthermore, the amplitude of the fifth detection signal R is at its maximum at the center of the width of the first magnetic pole 205.

[0152] Similar to the second embodiment, the signal processing unit 120 acquires the main signal S14 (=2B-A-C) and the sub-signal S15 (=L-R). In addition, the control unit 123 acquires the position signal and the phase signal.

[0153] Furthermore, when the magnetized rotor 204 is rotating in the forward direction, around time T3, the amplitude of the main signal S14 becomes greater than the binarization threshold. Therefore, the position signal changes from Lo to Hi. Additionally, since the amplitude of the sub-signal S15 is less than the binarization threshold, the binarized phase signal becomes Lo. Thus, since both the position signal rising from Lo to Hi and the phase signal being Lo are satisfied, the control unit 123 determines that the magnetized rotor 204 is rotating forward. The signal processing unit 120 outputs the rotation mode signal decreasing at time T3 as a signal indicating forward rotation to an external device.

[0154] On the other hand, when the rotation direction of the magnetized rotor 204 is reversed, around time T3, the amplitude of the main signal S14 becomes smaller than the binarization threshold. Therefore, the position signal changes from Hi to Lo. Furthermore, since the amplitude of the sub-signal S15 is smaller than the binarization threshold, the binarized phase signal becomes Lo. Thus, since both the position signal decreasing from Hi to Lo and the phase signal being Lo are satisfied, the control unit 123 determines that the magnetized rotor 204 is rotating in reverse. The signal processing unit 120 outputs the rotation mode signal, which decreases at time T3 and has a pulse width larger than in the case of forward rotation, as a signal indicating reverse rotation to an external device.

[0155] As described above, a magnetized rotor 204 can also be used as the rotating body. In this embodiment, the same effects as in the first and second embodiments can be obtained.

[0156] As a variation, such as Figure 20 and Figure 21 As shown, the rotation detection device 100 may also be without the bias magnet 101. Figure 20 This indicates the use of GMR or TMR elements as elements 104-106, 130, and 131. In this case, in the rotation direction of the magnetized rotor 204, the amplitudes of the first detection signal A and the third detection signal C reach their maximum values ​​at the width center of the first magnetic pole 205. The amplitude of the second detection signal B reaches its maximum value at the width center of the second magnetic pole 206. The amplitude of the fourth detection signal L reaches its maximum value at the boundary where the first magnetic pole 205 switches to the second magnetic pole 206. The signal processing unit 120, similar to the second embodiment, acquires the main signal S16 (=2B-A-C) and the sub-signal S17 (=L-R).

[0157] Figure 21 This indicates the use of AMR elements as elements 104-106, 130, and 131. In this case, the definition of a certain interval differs from that described above. Here, the certain interval is defined as b. The certain interval b is the length between the width center of the first magnetic pole 205 and the width center of the second magnetic pole 206 in the rotation direction of the magnetized rotor 204. The first magnetic detection element 104 and the third magnetic detection element 106 are arranged with an interval of b. Similarly, the fourth magnetic detection element 130 and the fifth magnetic detection element 131 are arranged with an interval of b / 2. In this case, in the rotation direction of the magnetized rotor 204, the amplitude of the first detection signal A and the third detection signal C is zero at the width center of the second magnetic pole 206. The amplitude of the second detection signal B is zero at the boundary between the first magnetic pole 205 and the second magnetic pole 206. The amplitude of the fourth detection signal L is at its maximum value at the width center of the second magnetic pole 206. The fifth detection signal R has its maximum amplitude at the boundary between the first magnetic pole 205 and the second magnetic pole 206. The signal processing unit 120, in the same manner as in the second embodiment, acquires the main signal S18 (=2B-A-C) and the sub-signal S19 (=L-R).

[0158] Furthermore, in this embodiment, the magnetized rotor 204 corresponds to the rotating body. In this embodiment, the main signals S14 and S16 correspond to the differential signals. In this embodiment, the sub-signals S15 and S17 correspond to signals that have phase relative to the differential signals.

[0159] (Eighth Embodiment)

[0160] In this embodiment, the differences from the 7th embodiment will be mainly described. For example... Figure 22As shown, similar to the third embodiment, the detection unit 103 employs a magnetic detection method using a Hall element.

[0161] In this embodiment, in the rotation direction of the magnetized rotor 204, the amplitudes of the first detection signal A and the third detection signal C are at their maximum values ​​at the width center of the first magnetic pole 205. Furthermore, the amplitudes of the first detection signal A and the third detection signal C are at their minimum values ​​at the width center of the second magnetic pole 206. The amplitude of the second detection signal B is at its maximum value at the width center of the second magnetic pole 206. Furthermore, the amplitude of the second detection signal B is at its minimum value at the width center of the first magnetic pole 205.

[0162] In the rotational direction of the magnetized rotor 204, the amplitude of the fourth detection signal L is at its maximum at the boundary where it switches from the first magnetic pole 205 to the second magnetic pole 206. Furthermore, the amplitude of the fourth detection signal L is at its minimum at the boundary where it switches from the second magnetic pole 206 to the first magnetic pole 205. The amplitude of the fifth detection signal R is at its maximum at the boundary where it switches from the second magnetic pole 206 to the first magnetic pole 205. Furthermore, the amplitude of the fifth detection signal R is at its minimum at the boundary where it switches from the first magnetic pole 205 to the second magnetic pole 206.

[0163] The signal processing unit 120 acquires the main signal S20 (=2B-A-C) and the sub-signal S21 (=L-R) in the same manner as in the second embodiment. Furthermore, the control unit 123 processes the position signal and phase signal, and determines the rotation direction of the magnetized rotor 204, in the same manner as in the second embodiment. Therefore, the same effects as in the first and second embodiments can be obtained. As described above, a Hall element can also be used.

[0164] As a variation, it can also be like... Figure 23 As shown, the rotation detection device 100 does not have a bias magnet 101.

[0165] Furthermore, in this embodiment, the main signals S20 and S22 correspond to the differential signals. The sub-signals S21 and S23 in this embodiment correspond to signals that have phase relative to the differential signals.

[0166] This disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of this disclosure, as follows.

[0167] For example, the gear 200 and the magnetized rotor 204 may also be provided with a portion indicating the reference position of rotation.

[0168] When the rotating body is a magnetized rotor 204, two elements can be used, similar to the fifth embodiment. Alternatively, three elements can be used, similar to the first embodiment. Furthermore, four elements can be used, similar to the sixth embodiment.

[0169] The rotation detection device 100 is not limited to detecting gears and magnetized rotors assembled in the gearbox of a vehicle, but can also be used to detect the rotation of other parts of the vehicle and to detect rotating bodies outside the vehicle.

[0170] This disclosure is based on embodiments, but it should be understood that this disclosure is not limited to these embodiments and constructions. This disclosure also includes various modifications and equivalent variations. In addition, various combinations and forms, and further combinations and forms that include only one element or more thereof, also fall within the scope and spirit of this disclosure.

Claims

1. A rotation detection device, include: The detection unit, configured to have a predetermined gap with the outer periphery of a rotating body that is periodically arranged at certain intervals relative to rotational position information on its outer periphery, detects changes in the magnetic field received from the outer periphery due to changes in the rotational position of the rotating body as it rotates; and The signal processing unit, based on the detection results from the detection unit, obtains the rotational position information of the rotating body. The aforementioned detection unit includes a first magnetic element, a second magnetic element, a third magnetic element, a fourth magnetic element, and a fifth magnetic element. When the aforementioned interval is defined as 'a', the first magnetic element and the third magnetic element are configured to have an interval of 'a' in the rotational direction of the rotating body. The first magnetic element outputs a first signal, and the third magnetic element outputs a third signal that is in phase with the first signal. The second magnetic element is positioned between the first and third magnetic elements in the rotational direction of the rotating body, and outputs a second signal that has phase with the first and third signals and has the same period as the rotational position information. The fourth and fifth magnetic elements are arranged between the first and third magnetic elements in the rotational direction of the rotating body. The second magnetic element is positioned between the fourth and fifth magnetic elements in the rotational direction of the rotating body. The signal processing unit acquires the differential signal between the first processed signal and the second processed signal as rotational position information with the same period as the aforementioned fixed interval. The first processed signal is based on the second signal and has the same period as the second signal. The second processed signal is based on the first signal and the third signal and has phase relative to the first processed signal. Based on the detection results of the fourth and fifth magnetic elements, the signal processing unit obtains a signal with phase relative to the differential signal as rotation mode information of the rotating body.

2. The rotation detection device as described in claim 1, The first, second, third, fourth, and fifth magnetic elements are arranged along one of the concave magnetic contour lines. The concave magnetic contour lines bulge out relative to the outer periphery of the rotating body.

3. The rotation detection device as described in claim 1, The first, second, third, fourth, and fifth magnetic elements are arranged along one of the convex magnetic contour lines. The convex magnetic contour lines are concave relative to the outer periphery of the rotating body.

4. The rotation detection device as described in claim 1, The first, second, and third magnetic elements are configured to be closer to the outer periphery of the rotating body than the fourth and fifth magnetic elements.

5. The rotation detection device as described in claim 1, The second, fourth, and fifth magnetic elements are configured to be closer to the outer periphery of the rotating body than the first and third magnetic elements.

6. The rotation detection device as described in claim 1, The first, third, fourth, and fifth magnetic elements are configured to be closer to the outer periphery of the rotating body than the second magnetic element.

7. The rotation detection device as described in claim 1, The first, second, third, fourth, and fifth magnetic elements are each a pair of magnetoresistive elements whose resistance changes with the rotation of the aforementioned rotating body. The aforementioned detection unit includes a bias magnet that applies a bias magnetic field to the aforementioned magnetoresistive element. The bias magnet has a hollow portion in which a detection section is disposed. The first, second, third, fourth, and fifth magnetic elements are located outside the hollow portion of the bias magnet.

8. The rotation detection device as described in claim 1, The first, second, third, fourth, and fifth magnetic elements are each Hall elements. The aforementioned detection unit includes a bias magnet for applying a bias magnetic field to the aforementioned Hall element. The bias magnet has a cylindrical shape. The first, second, third, fourth, and fifth magnetic elements are arranged above the bias magnet in such a way that they face the outer periphery of the rotating body.

9. The rotation detection device as described in any one of claims 1 to 6, The first, second, third, fourth, and fifth magnetic elements are each a pair of magnetoresistive elements whose resistance changes with the rotation of the aforementioned rotating body. The aforementioned detection unit includes a bias magnet that applies a bias magnetic field to the aforementioned magnetoresistive element. The bias magnet has a hollow portion in which a detection section is disposed. The first, second, third, fourth, and fifth magnetic elements are located inside the hollow portion of the bias magnet.

10. A rotation detection device, include: The detection unit, configured to have a predetermined gap with the outer periphery of a rotating body that is periodically arranged at certain intervals relative to rotational position information on its outer periphery, detects changes in the magnetic field received from the outer periphery due to changes in the rotational position of the rotating body as it rotates; and The signal processing unit, based on the detection results from the detection unit, obtains the rotational position information of the rotating body. The aforementioned detection unit includes a first magnetic element, a second magnetic element, a third magnetic element, a fourth magnetic element, and a fifth magnetic element. When the aforementioned interval is defined as 2b, the first magnetic element and the third magnetic element are configured to have an interval of b in the rotational direction of the rotating body. The first magnetic element outputs a first signal, and the third magnetic element outputs a third signal that is in phase with the first signal. The second magnetic element is positioned between the first and third magnetic elements in the rotational direction of the rotating body, and outputs a second signal that has phase with the first and third signals and has the same period as the rotational position information. The fourth and fifth magnetic elements are arranged between the first and third magnetic elements in the rotational direction of the rotating body. The second magnetic element is positioned between the fourth and fifth magnetic elements in the rotational direction of the rotating body. The signal processing unit acquires the differential signal between the first processed signal and the second processed signal as rotational position information with the same period as the aforementioned fixed interval. The first processed signal is based on the second signal and has the same period as the second signal. The second processed signal is based on the first signal and the third signal and has phase relative to the first processed signal. Based on the detection results of the fourth and fifth magnetic elements, the signal processing unit obtains a signal with phase relative to the differential signal as rotation mode information of the rotating body.

11. The rotation detection device as described in claim 10, The fourth and fifth magnetic elements are arranged with a spacing of b / 2.

12. The rotation detection device as described in claim 10 or 11, The rotating body is a magnetized rotor having a first magnetic pole and a second magnetic pole alternately arranged along the rotation direction of the rotating body. The aforementioned interval is the length between the center position of the first magnetic pole and the center position of the adjacent second magnetic pole.

13. The rotation detection device as described in claim 12, The first, second, third, fourth, and fifth magnetic elements are each AMR elements.

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