JP2005061964A - Rotation angle sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation angle sensor capable of detecting a rotation angle of a rotating body with high accuracy.
A relay electrode substrate 3 is formed by equally dividing a circumferential direction at a predetermined wide-range angle and forming electrodes in some of the divided regions, thereby forming a desired electrode pattern as a whole. A wide-area relay electrode 11 to be formed and a narrow-area relay electrode 12 formed at a predetermined interval along the circumferential direction are provided. The transmission / reception electrode substrate 4 transmits a detection signal for wide-range angle detection, and receives a detection signal relayed by the wide-range relay electrode 11, a wide-range detection transmission electrode 13, a reception electrode 14, and a circumference. The two electrodes are arranged along the direction and opposed in the radial direction, and the two electrodes have a shape that gradually changes as the radial width moves in the circumferential direction. A narrow-range detection transmitting electrode 15 and a receiving electrode 16 are provided for transmitting a detection signal for detection and receiving a detection signal relayed by the narrow-range relay electrode.
[Selection] Figure 2

Description

  The present invention relates to a rotation angle sensor that detects a rotation angle of a rotating body.

As a rotation angle sensor for detecting the rotation angle of a rotating body, a sensor described in, for example, Japanese Patent Application Laid-Open No. 10-213411 (Patent Document 1) has been known. FIG. 11 is an explanatory diagram showing the configuration of the rotation angle detection device described in Patent Document 1. As shown in the figure, a rotation electrode 102 whose width varies along the circumferential direction is provided around the rotation shaft 101. In addition, a narrow fixed electrode 103 is provided on the fixed side which is the outer peripheral portion of the rotating electrode 102. Since the capacitance between the rotating electrode 102 and the fixed electrode 103 changes according to the rotation angle of the rotating shaft 101, the rotation of the rotating shaft 101 is measured by measuring the capacitance between the two electrodes. The angle can be determined.
JP-A-10-213411

  However, in the conventional example disclosed in Patent Document 1 described above, there is a problem in that the detection accuracy of the rotation angle is deteriorated when an axial deviation occurs between the rotation shaft 101 and the fixed electrode 103. In addition, since the rotation angle of the rotation shaft 101 is obtained using only one pattern of the rotation electrode 102, there is a problem that reliability is lacking.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a rotation angle sensor capable of detecting the rotation angle of a rotating body with high accuracy. is there.

  In order to achieve the above object, the invention according to claim 1 of the present application is a rotation angle sensor for detecting a rotation angle of a rotating body, and is attached to a first disk attached to a rotating shaft of the rotating body and a fixed side. And a second disk disposed oppositely in close proximity to the first disk, the first disk equally dividing the circumferential direction at a predetermined wide-range angle, and for each of the divided areas. A wide range relay electrode that forms a desired electrode pattern as a whole by forming electrodes in some of the regions, and a narrow range relay electrode formed at a predetermined interval along the circumferential direction, A plurality of the second disks are arranged at equiangular intervals at positions facing the wide-area relay electrode, transmit detection signals for wide-range angle detection, and detect signals relayed by the wide-area relay electrode Transmission / reception means for wide-range detection The two electrodes are arranged along the circumferential direction and opposed in the radial direction, and the two electrodes have a shape that gradually changes as the radial width moves in the circumferential direction; A transmission / reception unit for narrow-range detection that transmits a detection signal for narrow-range angle detection and receives a detection signal relayed by the narrow-range relay electrode, and further includes the transmission / reception unit for wide-range detection, and the Control means for outputting a transmission signal to the narrow-range detection transmitting / receiving means and processing the received reception signal to obtain the rotation angle of the rotating body is provided.

  According to a second aspect of the present invention, the wide range relay electrode is configured so that the opposing relationship with the wide range detection transmitting / receiving means is all changed by moving the wide range angle by setting the presence / absence of an electrode for each wide range angle. It is characterized by setting differently.

  The invention described in claim 3 is characterized in that the two electrodes of the narrow-range detection transmitting / receiving means are each configured in a right triangle shape, and the hypotenuses of each right triangle face each other.

  According to a fourth aspect of the present invention, the narrow range relay electrode is formed in a narrow bar shape, and the control means includes the narrow range relay electrode and two electrodes of the narrow range detection transmitting / receiving means. An angle smaller than the wide-range angle is detected based on the capacitance between them.

  The invention described in claim 5 is characterized in that the center angle of the two electrodes of the narrow-width detecting transmission / reception means with respect to the arc along the circumferential direction is larger than the wide range angle.

  The invention described in claim 6 is characterized in that two of the narrow width detecting transmission / reception means are arranged at an angle different from the central angle with respect to the arc.

  The invention according to claim 7 further includes a third disk that is arranged coaxially with the rotating shaft and is rotatable with respect to the rotating shaft, wherein the second disk is a signal for detecting the number of turns. The third disk rotates at a predetermined reduction ratio with respect to the first disk, and the detection signal output from the circulation number detecting transmission / reception means is provided. The circuit includes a circulation number relay electrode to be relayed, transmits a detection signal for the number of circulation detection from the circulation number detection transmission / reception means, receives a detection signal relayed by the circulation number relay electrode, and the control means The number of rotations of the rotating shaft is obtained based on the received detection signal.

  According to an eighth aspect of the present invention, the third disk is disposed opposite to a surface of the second disk opposite to the surface facing the first disk with a predetermined distance therebetween. Features.

  According to a ninth aspect of the present invention, the number-of-turns relay electrode is divided at an angle corresponding to one rotation of the first disk along the circumferential direction, and is formed in the divided area. The electrodes are different from each other in the area facing the transmitting / receiving means for detecting the number of turns.

  According to a tenth aspect of the present invention, the control unit detects a capacitance between the circulation number detecting transmission / reception unit and the circulation number relay electrode, and based on the capacitance, the first It is characterized by obtaining the number of rounds of the disk.

  According to an eleventh aspect of the present invention, the rotating body is a steering shaft mounted on a vehicle.

  In the rotation angle sensor according to the present invention, since the detection signal transmitted from the wide-range detection transmitting / receiving means receives the signal relayed by the wide-area relay electrode, the rotation at every angle set as a wide range (for example, 15 degrees). The rotation angle of the body can be obtained. Furthermore, since the detection signal transmitted from the narrow-range detection transmission / reception means receives the signal relayed by the narrow-range relay electrode, it is possible to detect an angle smaller than a wide range and to accurately detect the rotation angle of the rotating body. Can be requested.

  In addition, by setting the signals received by the wide-range detection transmission / reception means to be different for each angle set as a wide range, it is possible to uniquely identify the wide-range angle and further improve the detection accuracy. Can do.

  Furthermore, by forming the narrow-area relay electrode into two right-angled triangles and facing these hypotenuses, the capacitance between the narrow-area relay electrode and the narrow-area relay electrode formed in a narrow bar shape can be reduced. Therefore, the angle detection accuracy in a narrow range can be improved.

  Further, the center angle of the two electrodes of the narrow width detecting transmission / reception means with respect to the arc along the circumferential direction is set to an angle (for example, 45 degrees) larger than an angle (for example, 15 degrees) set as a wide range. Therefore, angle detection is performed in a narrow range with a margin before and after each wide angle detected by the wide-range detection transmission / reception means, so even if a detection error occurs in the wide-range detection transmission / reception means However, angle detection that compensates for this is possible.

  Further, two narrow range detecting transmission / reception means are arranged, and the central angle between the two is set as an angle (for example, 30 degrees) different from the central angle (for example, 45 degrees) of the narrow range detection transmitting / receiving means. By doing so, the two narrow-range detection transmitting / receiving means can receive a signal having a phase difference. Since it can be determined whether or not a detection error has occurred based on this phase difference, the detection accuracy can be further improved.

  In addition, by arranging a third disk that rotates at a reduced speed with respect to the first disk, the detection signal output from the circulation number detection transmitting / receiving means receives a signal obtained by relaying the circulation number relay electrode, Since the number of rotations of the rotating body can be detected, an absolute rotation angle over a plurality of rotations of the rotating body that rotates a plurality of times can be obtained.

  Furthermore, the circulation relay electrode is divided for each angle corresponding to one rotation of the first rotating disk, and the area facing the circulation detection transmitting / receiving means is set to be different for each angle. Since the number of rotations of the rotating body is obtained based on the electrostatic capacitance between the electrode and the number-of-turns detecting transmission / reception means, it is possible to detect the number of rotations with higher accuracy.

  Further, if the rotation angle of the steering shaft of the vehicle is obtained as the rotating body, the absolute rotation angle of the steering shaft that rotates 4 to 5 in total can be obtained with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a configuration of a rotation angle sensor according to the first embodiment of the present invention. As shown in the figure, the rotation angle sensor 1 detects the rotation angle of a rotating shaft (rotating body) 2 such as a steering shaft of a vehicle, and is connected to a relay electrode substrate (first electrode) that rotates with the rotating shaft 2. A disc 3) and a transmission / reception electrode substrate (second disc) 4 provided on the fixed side that is disposed to face the relay electrode substrate 3 with a predetermined interval and does not rotate with the rotary shaft 2. Further, the transmission / reception electrode substrate 4 is connected to a control circuit (control means) 5.

  2A is an explanatory diagram showing the configuration of the surface of the transmission / reception electrode substrate 4 facing the relay electrode substrate 3, and FIG. 2B is the diagram of the surface of the relay electrode substrate 3 facing the transmission / reception electrode substrate 4. FIG. It is explanatory drawing which shows a structure. In addition, the figure (a), (b) has shown the surface which mutually faces. Therefore, the code “A” and the code “A ′” face each other, and the code “B” and the code “B ′” face each other.

  As shown in FIG. 2B, a wide-area relay electrode 11 is formed on the inner peripheral side of the relay electrode substrate 3, and a narrow-area relay electrode 12 is formed on the outer peripheral side. The wide-area relay electrode 11 includes predetermined electrode patterns 11a to 11e formed in units of 15 degrees along the circumference (360 degrees).

  The electrode pattern 11a is formed in an arc shape with a central angle of 30 degrees, the electrode pattern 11b is formed in an arc shape with a central angle of 15 degrees, and the electrode pattern 11c is formed in an arc shape with a central angle of 30 degrees. 11d is formed in an arc shape with a central angle of 75 degrees, and the electrode pattern 11e is formed in an arc shape with a central angle of 15 degrees.

  A space for a central angle of 30 degrees is provided between the electrode patterns 11a and 11b, a space for a central angle of 60 degrees is provided between the electrode patterns 11b and 11c, and a space between the electrode patterns 11c and 11d is provided. A space for a central angle of 30 degrees is provided, a space for a central angle of 60 degrees is provided between the electrode patterns 11d and 11e, and a space for a central angle of 15 degrees is provided between the electrode patterns 11e and 11a. Is provided.

  On the other hand, the narrow-area relay electrode 12 is configured as a narrow bar-shaped electrode, and is formed at eight intervals of 45 degrees along the circumference.

  Further, as shown in FIG. 2 (a), five wide areas arranged at intervals of 30 degrees at positions facing the above-described wide-area relay electrode 11 on the inner peripheral side of the transmission / reception electrode substrate 4 are provided. Detection transmission electrodes 13-1 to 13-5 and wide-range detection reception electrodes 14-1 to 14-5 are formed.

  Further, two narrow-range detection transmission electrodes 15-1 and 15-2 and a narrow-range detection reception electrode 16- are provided at positions on the outer peripheral side of the transmission / reception electrode substrate 4 that face the narrow-range relay electrode 12 described above. 1, 16-2 are provided. Each of the narrow range detection transmission electrodes 15-1 and 15-2 and the narrow range detection reception electrodes 16-1 and 16-2 is formed in an arc shape having a central angle of 45 degrees, and two narrow range detection transmission electrodes are formed. A space for a central angle of 30 degrees is provided between the electrodes 15-1 and 15-2.

  Further, as shown in FIG. 3, the narrow-range detection transmitting electrodes 15-1 and 15-2 are separated into two electrodes, a first electrode 15a and a second electrode 15b, each having a right triangular shape. The hypotenuses of the electrodes 15a and 15b are arranged facing each other. Then, according to the relative positional relationship with the narrow range relay electrode 12, the capacitance C1 between the first electrode 15a and the narrow range relay electrode 12, and the second electrode 15b and the narrow range relay electrode 12 are provided. The capacitance C2 between and changes.

  FIG. 4 is a block diagram showing a configuration of the control circuit 5. As shown in the figure, the control circuit 5 outputs a pulse signal for detection to the microcomputer 5a serving as a control center and the transmission electrodes 13-1 to 13-5 for wide range detection, and also receives for each wide range detection. A wide-range signal detection circuit 5b for detecting signals received by the electrodes 14-1 to 14-5, and a pulse signal for detection to each of the narrow-range detection transmission electrodes 15-1 and 15-2, and each narrow-band detection signal A narrow-range signal detection circuit 5c that detects signals received by the range detection receiving electrodes 16-1 and 16-2, and a multiplexer 5d that performs time-division processing on a digital signal output from the wide-range signal detection circuit 5b are provided. Yes.

  Next, the operation of the rotation angle sensor 1 according to this embodiment configured as described above will be described.

  When the rotating shaft 2 rotates, the relative positional relationship between the relay electrode substrate 3 rotating together with the rotating shaft 2 and the fixed transmitting / receiving electrode substrate 4 changes. Here, in the state shown in FIGS. 2 (a) and 2 (b), the positions where the two substrates 3 and 4 face each other, that is, "A" and "A '", "B" and "B'" Is a rotation angle of 0 degree, and the direction indicated by the arrow “Y1” in FIG.

  Now, when the rotation angle of the relay electrode substrate 3 is in the range of 0 degrees to 15 degrees, the electrode 14-4 of the five wide-range detection receiving electrodes 14-1 to 14-5 faces the wide-area relay electrode 11a. The other electrodes 14-1 to 14-3 and 14-5 do not face any wide-area relay electrodes 11a to 11e. Accordingly, the received signal is detected only by the wide-range detection receiving electrode 14-4.

  Furthermore, when the rotation angle of the relay electrode substrate 3 is in the range of 15 degrees to 30 degrees, the electrode 14-4 of the five wide-area relay electrodes 14-1 to 14-5 faces the wide-area relay electrode 11a, In addition, the electrode 14-3 faces the wide-area relay electrode 11e. Accordingly, the reception signal is detected by the wide-range detection receiving electrodes 14-3 and 14-4.

  Similarly, when the relay electrode substrate 11 rotates in the direction of the arrow “Y1”, detection signals are output from the wide-range detection receiving electrodes 14-1 to 14-5 as shown in the characteristic diagram of FIG. In the waveform diagram shown in the figure, “H” level is detected and “L” level is not detected.

そして、上記の表１から理解されるように、２進５桁で示される各デジタル信号は、１５度毎に区切った各区間で、それぞれ異なる値となるように設定されているので、このデジタル信号に基づいて、中継電極基板１１、ひいては回転軸２の、１５度単位での回転角度を求めることができる。 When this detection result is represented by a digital signal, a binary 5-digit signal as shown in Table 1 below is obtained. For example, when the rotation angle is in the range of 0 to 15 degrees, a digital signal “00010” is obtained.

As can be understood from Table 1 above, each digital signal indicated by 5 binary digits is set to have a different value in each section divided every 15 degrees. Based on the signal, the rotation angle of the relay electrode substrate 11 and thus the rotation shaft 2 in units of 15 degrees can be obtained.

  Further, the narrow-range detection transmitting electrodes 15-1 and 15-2 each have an angle that becomes a central angle of 45 degrees, and therefore, of the eight narrow-range relay electrodes 12 provided at intervals of 45 degrees. It will face either one. And, as shown in FIG. 3, the narrow range detection transmission electrodes 15-1 and 15-2 are divided into a first electrode 15a and a second electrode 15b formed in a triangular shape, The narrow range relay electrode 12 is positioned so as to straddle the two electrodes 15a and 15b, and according to the relative positional relationship between the narrow range transmission electrodes 15-1 and 15-2 and the narrow range relay electrode 12. Thus, the capacitances C1 and C2 change. In the microcomputer 5a shown in FIG. 4, the relative positional relationship between the narrow-range transmission electrodes 15-1 and 15-2 and the narrow-range relay electrode 12 is calculated by calculating the capacitance ratio, that is, Thus, it is possible to detect at which angular position of the narrow-range transmission electrodes 15-1 and 15-2 having an arc of 45 degrees as a whole, the narrow-range relay electrode 12 exists.

  Next, a specific rotation angle detection process in the microcomputer 5a will be described with reference to the flowchart shown in FIG. First, a signal detected by the wide range signal detection circuit 5b is read (step ST1). Then, in order to perform highly accurate detection, this reading operation is repeated three times (step ST2).

  If the detection signals are the same in the three detections (step ST3), a wide range of angles are determined (step ST4). That is, by applying the binary 5-digit digital signal detected by the wide-range signal detection circuit 5b to the above-mentioned Table 1, the rotation angle of the relay electrode substrate 12 is specified in the range of 15 degrees.

  Next, a voltage signal output based on the positional relationship between the narrow range detection transmission electrodes 15-1 and 15-2 and the narrow range relay electrode 12 is detected and A / D converted (step ST5). That is, as shown in FIG. 3, the narrow-range relay electrode 12 is arranged so as to straddle the two electrodes 15a and 15b of the narrow-range detection transmitting electrodes 15-1 and 15-2 having an angle of 45 degrees. Therefore, by measuring the ratio of the reception voltage that varies depending on the magnitudes of the capacitances C1 and C2, it is possible to detect at which position of the 45-degree range the narrow-range relay electrode 12 exists. , A fine angle detection within a range of 45 degrees is possible.

  Then, based on the signal detected by the wide-range signal detection circuit 5b and the signal detected by the narrow-range signal detection circuit 5c, the rotation angle of the rotary shaft 2 is obtained (step ST6). Thereafter, this data is output (step ST7). Thus, the rotation angle of the rotating shaft 2 can be obtained with high accuracy.

  Since the rotation angle in units of 15 degrees is specified by the wide-range detection transmission electrodes 13-1 to 13-5, the narrow-range detection transmission electrodes 15-1 and 15-2 are at the center of at least 15 degrees. In this embodiment, in order to improve the detection accuracy, there is a margin before and after the 15-degree range detected by the wide-range detection transmission electrodes 13-1 to 13-5. Is set to 15 degrees, and a narrow range of angles is detected within a range of 45 degrees as a whole.

  Furthermore, in the present embodiment, by providing the two narrow range detection transmitting electrodes 15-1 and 15-2, more accurate angle detection is possible. That is, the voltage received by the narrow-range detection receiving electrodes 16-1 and 16-2 by using the two narrow-range detection transmitting electrodes 15-1 and 15-2 arranged at an interval of 30 degrees. The signal should be 15 degrees out of phase (45-30 = 15 degrees). In the microcomputer 5a shown in FIG. 4, this phase difference is detected, and if the deviation is not 15 degrees, it can be determined that a detection error has occurred.

  If such a function is not required, it is not necessary to provide two narrow-range detection transmitting electrodes 15-1 and 15-2 and narrow-range detection receiving electrodes 16-1 and 16-2. It is also possible to use either one.

  In this manner, in the rotation angle sensor 1 according to the present embodiment, the detection signal is transmitted from the wide-range detection transmission electrodes 13-1 to 13-5 and is opposed to the wide-area relay electrode 11, thereby detecting the wide-range detection. Based on the signals received by the receiving electrodes 14-1 to 14-5, the rotation angle of the relay electrode substrate 3 can be detected in units of 15 degrees. Further, by using the narrow range detection transmission electrodes 15-1 and 15-2 and the narrow range detection reception electrodes 16-1 and 16-2, a fine angle signal of 15 degrees or less can be detected. Based on these detection signals, it is possible to detect the rotation angle of the relay electrode substrate 3, and thus the rotation shaft 3, with extremely high accuracy.

  Further, in each of the narrow-range detection receiving electrodes 16-1 and 16-2, a method for obtaining the rotation angle of the rotating shaft 2 based on the capacitance ratio between the two electrodes 15a and 15b and the relay electrode 12 is used. Since it is employed, even when the distance between the relay electrode substrate 3 and the transmission / reception electrode substrate 4 changes, the measurement accuracy does not decrease. In addition, since various electrode patterns formed on the relay electrode substrate 3 are designed to be large in the radial direction, even when an axial deviation occurs, the influence is small, and highly accurate detection can be maintained. .

  Next, a second embodiment of the present invention will be described. FIG. 7 is a cross-sectional view showing the configuration of the rotation angle sensor according to the second embodiment. As shown in the figure, the rotation angle sensor 21 includes a relay electrode substrate 22 that rotates together with the rotating shaft 2, a transmission / reception electrode substrate 23 attached to the fixed side, and a rotation angle relay electrode substrate 22 of the transmission / reception electrode substrate 23. And is provided with a circulation relay electrode substrate (third disk) 24 that can be rotated with respect to the rotary shaft 2.

  Further, the transmission / reception electrode substrate 23 is provided with a speed reduction mechanism including a first gear 25 and a second gear 26. The first gear 25 has a larger diameter than the second gear 26 (that is, has a larger number of teeth) and meshes with gear teeth formed on the outer peripheral portion of the rotation angle relay electrode substrate 22. On the other hand, the second gear 26 meshes with gear teeth formed on the outer peripheral portion of the circulation relay electrode substrate 24.

  Accordingly, the rotation operation of the rotation angle relay electrode substrate 22 is decelerated and transmitted to the circulation relay electrode substrate 24. In this embodiment, the reduction ratio is set to 1/5 as an example. That is, when the rotation angle relay electrode substrate 22 rotates five times, the number of rotations relay electrode substrate 24 rotates once.

  The surface of the rotation angle relay electrode substrate 22 facing the transmission / reception electrode substrate 23 is the same as the configuration shown in FIG. 2B shown in the first embodiment, and the transmission / reception electrode substrate 23. The surface facing the rotation angle relay electrode substrate 22 is the same as FIG. Therefore, the description of the configuration is omitted. In the rotation angle sensor 1 shown in the first embodiment, the content of obtaining the rotation angle of the rotation shaft 2 in the range of 360 degrees has been described, but in this embodiment, the number of rotations of the rotation shaft 2 is also measured.

  FIG. 8A is an explanatory diagram showing the configuration of the surface (hereinafter referred to as A surface) of the circulation relay electrode substrate 24 facing the transmission / reception electrode substrate 23, and FIG. 8B shows the configuration of the transmission / reception electrode substrate 23. It is explanatory drawing which shows the structure of the surface (henceforth B surface) facing the frequency | count relay electrode substrate 24. FIG.

  As shown in FIG. 4B, the B surface has a narrow and rod-shaped number-of-times-detecting transmission electrode 27 formed on the outer peripheral side across the center line that divides the radial direction into two, and the inner peripheral side. In addition, a reception electrode 28 for detecting the number of rounds of a narrow bar-like shape is formed.

  Further, as shown in FIG. 5A, the A surface is divided into five in the circumferential direction (that is, equally divided at 72 degrees), and each region is centered on a central line that divides the radial direction into two substantially. The circular arc-shaped number-of-times relay electrodes 32-1 to 32-5 are formed. The electrode width is gradually increased from the circulation relay electrodes 32-1 to 32-5.

  FIG. 9 is a block diagram illustrating a circuit number detection processing circuit of the rotation angle sensor 21 according to the second embodiment. As shown in the figure, the circuit number detection processing circuit includes a CV conversion circuit 29 that converts capacitance detected by the circuit number detection receiving electrode 28 into a voltage signal, and a CV conversion circuit 29. Is provided with a comparator 30 that compares the voltage signal obtained in step 1 with a preset threshold voltage, and a microcomputer 31 that obtains the number of rotations of the rotating shaft 2 based on the comparison result by the comparator 30.

  Next, the operation of the rotation angle sensor 21 according to the second embodiment configured as described above will be described. As described above, when the rotation angle relay electrode substrate 22 is rotated five times, the circulation relay electrode substrate 24 is rotated once. Accordingly, when the rotation angle relay electrode substrate 22 rotates once, the circulation relay electrode substrate 24 rotates 72 degrees. That is, it is rotated by an angle corresponding to one area shown in FIG.

  When the number of turns is the first rotation, the number-of-turns detection transmitting electrode 27 and the receiving electrode 28 face the number-of-turns relay electrode 32-1.

  At this time, since the detection signal transmitted from the circulation number detection transmitting electrode 27 is received by the circulation number detection receiving electrode 28 via the circulation number relay electrode 32-1, the reception signal is The level according to the electrostatic capacitance between the transmission electrode 27 for frequency detection and the relay relay electrode 32-1 and the capacitance between the reception electrode 28 for frequency detection and the relay relay electrode 32-1. Signal. This signal is converted into a voltage signal by the C-V conversion circuit 29 and compared with a preset threshold voltage by the comparator 30.

  As shown in FIG. 10, the threshold voltage is set so as to change stepwise from the region of the circulation relay electrode 32-1 to the region of the electrode 32-5.

  If the detected voltage signal is in the range of threshold values Th0 to Th1, the number of turns is determined to be the first rotation. Similarly, if it is in the range of threshold values Th1 to Th2, the number of laps is determined to be the second rotation. Hereinafter, in the case of the third rotation in Th2 to Th3, the fourth rotation in the range of Th3 to Th4, and Th4 or more. The fifth rotation is determined. Thus, the number of rotations of the rotating shaft 2 is detected.

  As described above, in the rotation angle sensor 2 according to the present embodiment, the rotation angle within 360 degrees of the rotation shaft 2 can be obtained by the method shown in the first embodiment described above, and the number of rotations is relayed. Since the electrode substrate 24 is provided, and the transmitter / receiver electrode substrate 23 is equipped with the transmission electrode 27 for detecting the number of rotations and the reception electrode 28 for detecting the number of rotations, the number of rotations of the rotating shaft 2 can also be measured. The rotation angle over a plurality of rotations can be measured with high accuracy.

  Further, since the number of rotations of the rotating shaft 3 is obtained using the change in capacitance, the power consumption can be significantly reduced. Moreover, the rotation angle over a plurality of rotations of the rotation shaft can be obtained without using an auxiliary power source.

  Therefore, for example, when measuring the rotation angle of the steering shaft of the vehicle as the rotation shaft 2, the rotation angle of the steering shaft that rotates a plurality of times can be detected together with the number of revolutions, which is extremely useful.

  The rotation shaft to be detected by the rotation angle sensor according to the present invention can be applied to a throttle sensor, a television turntable, a cam position sensor, or the like in addition to the above-described steering shaft.

  Although the rotation angle sensor of the present invention has been described based on the illustrated embodiment, the present invention is not limited to this, and the configuration of each part is replaced with an arbitrary configuration having the same function. Can do.

  It is extremely useful for devices and devices that need to detect the rotation angle with high accuracy.

It is a perspective view which shows the structure of the rotation angle sensor which concerns on the 1st Embodiment of this invention. (A) is explanatory drawing which shows the structure of the surface facing a relay electrode board | substrate of a transmission / reception electrode board | substrate, (b) is explanatory drawing which shows the structure of the surface of a relay electrode board | substrate facing a transmission / reception electrode board | substrate. It is explanatory drawing which shows the positional relationship of the transmission electrode for narrow range detection, the reception electrode for narrow range detection, and a narrow range relay electrode. It is a block diagram which shows the structure of the control circuit mounted in the rotation angle sensor which concerns on 1st Embodiment. It is a characteristic view showing a change of a signal detected with each receiving electrode for wide range detection when a rotating shaft rotates. It is a flowchart which shows the detection process of the rotation angle by the rotation angle sensor which concerns on 1st Embodiment. It is a cross-sectional view which shows the structure of the rotation angle sensor which concerns on the 2nd Embodiment of this invention. (A) is explanatory drawing which shows the structure of the surface which opposes the frequency | count relay electrode substrate of a transmission / reception electrode board | substrate, and (b) opposes the transmission / reception electrode board | substrate of a frequency relay electrode substrate according to 2nd Embodiment. It is explanatory drawing which shows the structure of a surface. It is a block diagram of a processing circuit for detecting the number of laps. It is a characteristic view which shows the relationship between the magnitude | size of the voltage signal at the time of detecting the frequency | count, and a threshold value. It is explanatory drawing which shows the structure of the conventional rotation angle detection apparatus.

Explanation of symbols

1 Rotation angle sensor 2 Rotating shaft (Rotating body)
3 Relay electrode substrate (first disk)
4 Transmitting and receiving electrode substrate (second disk)
5 Control circuit (control means)
DESCRIPTION OF SYMBOLS 11 Wide-range relay electrode 12 Narrow-range relay electrode 13 Wide-range detection transmission electrode 14 Wide-range detection reception electrode 15 Narrow-range detection transmission electrode 16 Narrow-range detection reception electrode 21 Rotation angle sensor 22 Rotation-angle relay electrode substrate (first disk) )
23 Transmission / reception electrode substrate (second disk)
24 relay electrode substrate (third disk)
25 1st gear 26 2nd gear 27 Transmitting electrode for detecting the number of laps 28 Receiving electrode for detecting the lap times 29 CV conversion circuit 30 Comparator 31 Microcomputer 32 Repeating electrode for the lap times

Claims (11)

In the rotation angle sensor that detects the rotation angle of the rotating body,
A first disk attached to the rotating shaft of the rotating body, and a second disk attached to the fixed side and disposed in close proximity to the first disk,
The first disk has a wide area that forms a desired electrode pattern as a whole by equally dividing the circumferential direction at a predetermined wide range angle and forming electrodes in some of the divided areas. A relay electrode, and a narrow-range relay electrode formed at a predetermined interval along the circumferential direction,
A plurality of the second disks are arranged at equiangular intervals at positions facing the wide-area relay electrode, transmit detection signals for wide-range angle detection, and detect signals relayed by the wide-area relay electrode A transmission / reception means for wide-range detection for receiving
The two electrodes are arranged along the circumferential direction and are opposed to each other in the radial direction, and the two electrodes have a shape that gradually changes as the radial width moves in the circumferential direction. Transmitting a detection signal for detecting a range angle, and receiving and transmitting a detection signal relayed by the narrow range relay electrode, narrow range detection transmitting and receiving means,
And a control means for outputting a transmission signal to the wide-range detection transmission / reception means and the narrow-range detection transmission / reception means and processing the received reception signal to obtain a rotation angle of the rotating body. A rotation angle sensor. The wide-area relay electrode is set so that the facing relationship with the wide-range detection transmitting / receiving means is different every time the wide-angle angle moves by setting the presence / absence of an electrode for each wide-angle angle. The rotation angle sensor according to claim 1. The two electrodes of the narrow-range detection transmitting / receiving means are each formed in a right triangle shape, and the hypotenuses of each right triangle face each other and are arranged to face each other. The rotation angle sensor described. The narrow-range relay electrode is formed in a narrow bar shape, and the control means is based on a capacitance between the narrow-range relay electrode and two electrodes of the narrow-range detection transmitting / receiving means, The rotation angle sensor according to any one of claims 1 to 3, wherein an angle smaller than the wide range angle is detected. The center angle with respect to the circular arc along the circumferential direction of the two electrodes of the transmission / reception means for narrow width detection is larger than the wide range angle, according to any one of claims 1 to 4. The rotation angle sensor described. 6. The rotation angle sensor according to claim 5, wherein two of the narrow width detecting transmission / reception means are arranged at an angle different from a central angle with respect to the arc. A third disk disposed coaxially with the rotation axis and rotatable with respect to the rotation axis;
The second disk includes a frequency detection transmitting / receiving means for transmitting and receiving a frequency detection signal,
The third disk includes a circulation relay electrode that rotates at a predetermined reduction ratio with respect to the first disk and relays a detection signal output from the circulation detection transmitter / receiver.
A detection signal for detecting the number of laps is transmitted from the transmission / reception means for detecting the number of laps, and a detection signal relayed by the lap number relay electrode is received, and the control means is based on the received detection signal. The rotation angle sensor according to claim 1, wherein the rotation number of the rotation shaft is obtained. 8. The third disk according to claim 7, wherein the third disk is disposed opposite to a surface of the second disk opposite to the surface facing the first disk with a predetermined distance therebetween. Rotation angle sensor. The number-of-turns relay electrode is divided at an angle corresponding to one rotation of the first disk along the circumferential direction, and the relay electrode formed in the divided region is used for the number-of-turns detection transmission / reception. 9. The rotation angle sensor according to claim 7, wherein areas facing the means are different from each other. The control means detects a capacitance between the circulation number detecting transmission / reception means and the circulation frequency relay electrode, and obtains the circulation number of the first disk based on the capacitance. The rotation angle sensor according to claim 9. The rotation angle sensor according to any one of claims 7 to 9, wherein the rotating body is a steering shaft mounted on a vehicle.

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