JP2005043224A - Rudder angle detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rudder angle detecting device which makes it possible for a car-side host system to detect the neutral position of a steering shaft easily and surely. <P>SOLUTION: The rudder angle detecting device 1 is provided with detecting gears 3-4 which rotate in interlock with the steering shaft, a magnetometric sensor 32 for detecting the rotation angle of the detecting gear 3, a magnetometric sensor 42 for detecting the rotation angle of the detecting gear 4, and an AND circuit 5 which outputs a neutral position signal when the magnetometric sensors 32, 42 output Z-phase pulse signals together. On this occasion, the magnetometric sensors 32, 42 output the Z-phase pulse signals together, when the steering shaft is at the neutral position, and the frequency x1 of the magnetometric sensor 32 is prime to the frequency x2 of the magnetometric sensor 42. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a steering angle detection device that detects a steering angle of a steering shaft, and more particularly to a technique that can detect a neutral position of a steering shaft.

  Conventionally, a technique for detecting a neutral position of a steering shaft and detecting a steering angle of the steering shaft based on the detected neutral position is known (for example, Patent Document 1). The neutral position means the position of the steering shaft in a straight traveling state such as a vehicle.

  In this technique, a magnetized ring that is provided along the side surface of the steering shaft and rotates integrally with the steering shaft, a magnet provided at one location of the magnetized ring, and a circumference of the magnetized ring A magnetic sensor is provided.

  Here, when the magnet passes through the magnetic sensor, the magnetic sensor detects the magnetic lines of force of the magnet and outputs a detection signal. The magnetized ring is provided so that the magnet passes through the magnetic sensor when the steering shaft is in the neutral position.

  Accordingly, since the magnetic sensor can output a detection signal when the steering shaft is in the neutral position, the neutral position of the steering shaft can be detected based on the detection signal.

  However, since the steering shaft rotates at least once in both the left and right directions, the magnet passes through the magnetic sensor even when the steering shaft is in a position other than the neutral position (for example, a position rotated once from the neutral position). For this reason, the magnetic sensor outputs a detection signal even when the steering shaft is in a position other than the neutral position.

  Therefore, in this technique, in the host system on the vehicle side, it is necessary to estimate which detection signal corresponding to the neutral position of the steering shaft among the detection signals output from the magnetic sensor.

For this reason, in this technique, the host system on the vehicle side has estimated that the detection signal output when the vehicle has traveled for a certain time or longer corresponds to the neutral position of the steering shaft.
JP 2000-180113 A

  However, in this technique, since the neutral position of the steering shaft cannot be detected unless the vehicle is driven for a certain period of time or longer, this detection takes time.

  The present invention has been made to solve such a conventional problem, and the main object of the present invention is to enable the host system on the vehicle side to easily and accurately detect the neutral position of the steering shaft. It is providing a rudder angle detection device.

  In order to achieve the above object, the invention according to claim 1 of the present application detects the rotation angle of the first detection gear and the first detection gear that rotate in conjunction with the steering shaft. When the detected rotation angle is an angle corresponding to the neutral position of the steering shaft, the first detection means for outputting the detection signal and the rotation angle of the second detection gear are detected, and the detection is performed. When the rotation angle is an angle corresponding to the neutral position of the steering shaft, the second detection means for outputting the detection signal, and the first detection means and the second detection means output the detection signal together. In this case, output means for outputting a neutral position signal indicating that the steering shaft is in the neutral position, and the first detection means and the second detection means are provided when the steering shaft is in the neutral position. Output signal and outputs together, the number of cycles of the first detecting means and the number of periods of the second detecting means, characterized in that it is a relatively prime.

  According to a second aspect of the present invention, in the rudder angle detection device according to the first aspect, the first detection means detects the detection signal when the rotation angle of the first detection gear is included in the first angle range. The second detection means outputs a detection signal when the rotation angle of the second detection gear is included in the second angle range.

  According to a third aspect of the present invention, in the rudder angle detecting device according to the second aspect, the first angle range and the second angle range are variable.

  The invention according to claim 4 is the rudder angle detection device according to claim 2 or 3, wherein the steering angle of the steering shaft corresponding to the first angle range is the first angle range and the second angle range, The steering range of the steering shaft that is smaller than the angle range obtained by dividing the period of the first detection means by the number of periods of the second detection means and that corresponds to the second angle range is the second detection means. Is set to be smaller than an angle range obtained by dividing the period by the number of periods of the first detection means.

  As described above, according to the invention described in the claims of the present application, the host system on the vehicle side can easily and accurately detect the neutral position of the steering shaft.

(First embodiment)
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. First, based on FIGS. 1-4, the structure of the steering angle detection apparatus 1 which concerns on the 1st Embodiment of this invention and the main functions of each component are demonstrated. 1 is a schematic configuration diagram showing the rudder angle detection device 1, FIG. 2 is a block diagram showing a control system of the rudder angle detection device 1, and FIG. 3 shows from the magnetic sensor 32 or the magnetic sensor 42. FIG. 4 is an explanatory diagram showing the content of the output signal, and FIG. 4 is a chart showing the relationship between the number of bits of the detection signal output from the magnetic sensors 32 and 42 and the steering angle detection resolution of the steering angle detection device 1. .

  As shown in FIG. 1, the steering angle detection device 1 is housed in a case 10, and includes a main gear 2, a detection gear (first detection gear) 3, and a detection gear (second detection). Gear) 4, magnets 31 and 41, magnetic sensor (first detection means) 32, magnetic sensor (second detection means) 42, and AND circuit (output means) 5.

  The main gear 2 rotates integrally with the steering shaft. Therefore, in the present embodiment, the steering range of the steering shaft and the rotation range of the main gear 2 coincide.

  Further, the steering range of the steering shaft is 0 to 2160 [deg] (corresponding to the steering range for three rotations in the left and right directions). The steering range may be another range.

  The detection gears 3 to 4 rotate in conjunction with the main gear 2, that is, the steering shaft. Note that the number of teeth of the detection gear 3 is larger than the number of teeth of the detection gear 4. Therefore, the detection gear 3 rotates at a slower rotational speed than the detection gear 4.

  The magnet 31 is a magnet magnetized in two poles, and is provided at the center of rotation of the detection gear 3. And it rotates with the gear 3 for a detection.

  The magnetic sensor 32 is installed in the vicinity of the magnet 31 and detects the direction of the lines of magnetic force of the magnet 31, that is, the rotation angle of the detection gear 3, in the range of 0 to 360 [deg] with the clockwise direction as the positive direction.

  Then, as shown in FIG. 3, it is possible to generate and output an n-bit (n is an integer of 6 to 10) digital signal corresponding to the detected rotation angle. In addition, the generated digital signal is converted into a three-phase (A-phase, B-phase, Z-phase) pulse signal, and the A-phase and B-phase pulse signals are output to the host system on the vehicle side as shown in FIG. The Z-phase pulse signal is output to the AND circuit 5.

Specifically, as shown in FIG. 3, when the detected rotation angle is 0 [deg], a digital signal having the lowest value (that is, 0) is generated, and the detected rotation angle is set to 0 [deg]. On the other hand, every time 360/2 ⁿ [deg] is increased, a digital signal having a larger value is generated. FIG. 3 shows an example where n = 6.

Here, 360/2 ⁿ [deg] is the rotation angle range of the detection gear 3 corresponding to each value of the digital signal, that is, the output resolution of the magnetic sensor 32. For example, when n = 6, the output resolution is 5.625 [deg]. The smaller the output resolution, the smaller the rotation angle range of the detection gear 3 corresponding to each value of the digital signal. Therefore, the magnetic sensor 32 can accurately detect the rotation angle of the detection gear 3.

  The magnetic sensor 32 outputs a pulse signal from the A phase and the B phase each time the value of the generated digital signal increases by four. The magnetic sensor 32 outputs a pulse signal in which an ON signal and an OFF signal are combined from the A phase and the B phase. In addition, after the pulse signal is output from the A phase, the pulse signal is output from the B phase at the timing when the value of the digital signal increases by one. Therefore, when the detection gear 3 rotates clockwise, the B-phase pulse signal is output with a delay of ¼ wavelength with respect to the A-phase pulse signal. Conversely, when the detection gear 3 rotates counterclockwise, the B-phase pulse signal is output 1/4 wavelength earlier than the A-phase pulse signal.

  The magnetic sensor 32 outputs a pulse signal (detection signal) from the Z phase when the value of the digital signal becomes a predetermined value (“000101” in the case shown in FIG. 3). Here, the range of the predetermined value can be freely changed, and the output timing and width of the pulse signal can be changed by changing the range.

  Here, the relationship between the output resolution of the magnetic sensor 32 and the steering angle detection resolution of the magnetic sensor 32 will be described with reference to FIG. The steering angle detection resolution means a steering range of the steering shaft corresponding to each value of the digital signal. Accordingly, the smaller the steering angle detection resolution is, the smaller the steering range of the steering shaft corresponding to each value of the digital signal is. Therefore, the magnetic sensor 32 can accurately determine the steering angle of the steering shaft. In the present embodiment, since the steering angle of the steering shaft is obtained using the magnetic sensor 32, the steering angle detection resolution of the magnetic sensor 32 becomes the steering angle detection resolution of the steering angle detection device 1 as it is.

  As shown in FIG. 4, the steering angle detection resolution of the magnetic sensor 32 is obtained by the following equation (1).

(Steering angle detection resolution of magnetic sensor 32) = (Output resolution of magnetic sensor 32) / (Speed ratio of detection gear 3) (1)
Here, the speed ratio of the detection gear 3 means an angle at which the detection gear 3 rotates while the steering shaft rotates by a unit angle, and is obtained by the following equation (2). Here, z0 is the number of teeth of the gear (in this embodiment, the main gear 2) that rotates integrally with the steering shaft, and z1 is the number of teeth of the detection gear 3.

(Speed ratio of the detection gear 3) = z0 / z1 (2)
Similarly, the steering angle detection resolution of the magnetic sensor 42 is obtained by the following equations (3) to (4). Here, z2 is the number of teeth of the detection gear 4.

(Steering angle detection resolution of magnetic sensor 42) = (Output resolution of magnetic sensor 42) / (Speed ratio of detection gear 4) (3)
(Speed ratio of the detection gear 4) = z0 / z2 (4)
For example, when the magnetic sensor 32 outputs a 6-bit digital signal and the speed ratio of the detection gear 3 is 5.625, the steering angle detection resolution of the magnetic sensor 32 is 1 [deg]. Here, it is desirable that the steering angle detection resolution is an integer or a finite decimal.

  A magnet 41 shown in FIG. 1 is a magnet magnetized in two poles, and is provided at the center of rotation of the detection gear 4. Then, it rotates together with the detection gear 4.

  The magnetic sensor 42 is installed in the vicinity of the magnet 41 and detects the direction of the magnetic lines of force of the magnet 41, that is, the rotation angle of the detection gear 4 in the range of 0 to 360 [deg] with the clockwise direction as the positive direction.

  Then, it is possible to generate and output an n-bit (n is an integer of 6 to 10) digital signal corresponding to the detected rotation angle. Further, the generated digital signal is converted into a three-phase (A phase, B phase, Z phase) pulse signal. Then, as shown in FIG. 2, among the three-phase pulse signals, a Z-phase pulse signal (detection signal) is output to the AND circuit 5. Specific generation, conversion, and output methods of the digital signal and the pulse signal are the same as those of the magnetic sensor 32.

  As shown in FIG. 2, the AND circuit 5 generates a neutral position signal indicating that the steering shaft is in the neutral position when both the Z-phase pulse signals are given from the magnetic sensors 32 and 42, and Output to the higher system.

  Next, how the cycle c1 of the magnetic sensor 32 and the cycle c2 of the magnetic sensor 42 are set will be described. Here, the period c1 of the magnetic sensor 32 is an angle at which the steering shaft rotates while the detection gear 3 rotates once, and the period c2 of the magnetic sensor 42 indicates the steering shaft while the detection gear 4 rotates once. Is an angle of rotation, and is obtained by the following equations (5) to (6).

c1 = 360 * z1 / z0 (5)
c2 = 360 * z2 / z0 (6)
The periods c1 to c2 are set so as to satisfy the following expression (7) so that the AND circuit 5 can output the neutral position signal only once within the steering range of the steering shaft.

(The least common multiple of c1 and c2) ≧ (steering range of steering shaft) (7)
Therefore, in the present embodiment, the periods c1 to c2 are set so that the least common multiple of the period c1 and the period c2 is 2160 [deg] or more.

  When the periods c1 to c2 satisfy the condition, the period number x1 of the magnetic sensor 32 and the period number x2 of the magnetic sensor 42 are relatively prime. Here, the cycle number x1 is the number of times the detection gear 3 rotates while the steering shaft rotates in the steering range. Similarly, the cycle number x2 is the number of times the detection gear 4 rotates while the steering shaft rotates in the steering range. The number of periods x1 to x2 is determined by the following formulas (8) to (9).

x1 = (the least common multiple of c1 and c2) / c1 (8)
x2 = (the least common multiple of c1 and c2) / c2 (9)
Next, the reason for setting the periods c1 to c2 in this way will be described with reference to FIGS. 5 to 6 by taking the case of (z0, z1, z2) = (135, 48, 34) as an example. 5 is a characteristic diagram showing the relationship between the steering angle of the steering shaft and the value of the digital signal output from the magnetic sensors 32 and 42, and FIG. 6 is output from the Z phase of the magnetic sensors 32 and 42. FIG. 6 is a characteristic diagram showing output timing of a pulse signal. FIG. 5 shows an example where n = 10.

  The broken line 20 shown in FIG. 5 shows the relationship between the steering angle (horizontal axis) of the steering shaft and the steering angle (vertical axis) of the steering shaft in the range of 0 to 360 [deg]. On the other hand, the broken line 30 indicates the relationship between the steering angle (horizontal axis) of the steering shaft and the value (vertical axis) of the digital signal output from the magnetic sensor 32. A broken line 40 indicates the relationship between the steering angle (horizontal axis) of the steering shaft and the value of the digital signal (vertical axis) output from the magnetic sensor 42. In addition, c0 in FIG. 5 is a cycle of a gear (main gear 2 in the present embodiment) that rotates integrally with the steering shaft.

  As shown in FIG. 5, since the period c1 is 128 [deg] and the period c2 is about 90.7 [deg], the least common multiple is about 2176 [deg]. Therefore, the periods c1 to c2 satisfy the condition of Expression (7).

  In this case, as shown in FIG. 5, within the steering range of the steering shaft, the combination of the digital signal output from the magnetic sensor 32 and the digital signal output from the magnetic sensor 42 is the steering shaft corresponding to the combination. When the steering angles are different, the steering angles are the same in the range of 0 to 360 [deg], but are different from each other.

  For example, when the steering angle of the steering shaft is 180 [deg] and 540 [deg] (in the range of 0 to 360 [deg], the steering angle is 180 [deg]), the magnetic sensor 32 is used. The digital signal values output from the magnetic sensor 42 are different values a1 and a2, respectively, and the digital signal values output from the magnetic sensor 42 are different values b1 and b2, respectively. Therefore, when the steering angle of the steering shaft is 180 [deg], the combination is (a1, b1). When the steering angle is 540 [deg], the combination is (a2, b2). It becomes.

  The magnetic sensors 32 and 42 output a Z-phase pulse signal when the value of the digital signal matches a predetermined value set in the magnetic sensors 32 and 42.

  Therefore, for example, when the steering angle of the steering shaft is 0 [deg] and the values of the digital signals output from the magnetic sensors 32 and 42 are a3 and b3, respectively, the predetermined values of the magnetic sensors 32 and 42 are respectively set. By setting a3 and b3, the magnetic sensors 32 and 42 output Z-phase pulse signals as follows. That is, as shown in FIG. 6, the magnetic sensor 32 outputs a Z-phase pulse signal when the value of the digital signal is a3, and the magnetic sensor 42 is when the value of the digital signal is b3. In addition, a Z-phase pulse signal is output.

  Here, since the speed ratio of the detection gears 3 and 4 is greater than 1, the magnetic sensors 32 and 42 output a Z-phase pulse signal a plurality of times within the steering range of the steering shaft. However, the magnetic sensors 32 and 42 output both Z-phase pulse signals only when the steering angle of the steering shaft is 0 [deg]. The combination of the digital signals is (a3, b3) because it is only when the steering angle of the steering shaft is 0 [deg].

  Therefore, when the values of the digital signals output by the magnetic sensors 32 and 42 when the steering shaft is in the neutral position are a4 and b4, respectively, the predetermined values of the magnetic sensors 32 and 42 are set to a4 and b4, respectively. The magnetic sensors 32 and 42 output Z-phase pulse signals as follows. That is, the magnetic sensor 32 outputs a Z-phase pulse signal when the value of the digital signal is a4 (an angle corresponding to the neutral position of the steering shaft). Similarly, the magnetic sensor 42 outputs a Z-phase pulse signal when the value of the digital signal is b4 (an angle corresponding to the neutral position of the steering shaft).

  Here, since the speed ratio of the detection gears 3 and 4 is greater than 1, the magnetic sensors 32 and 42 output a Z-phase pulse signal a plurality of times within the steering range of the steering shaft. However, the magnetic sensors 32 and 42 output both Z-phase pulse signals only when the steering shaft is in the neutral position. The combination of the digital signals is (a4, b4) because it is only when the steering shaft is in the neutral position.

  As described above, if the periods c1 to c2 satisfy the condition of the expression (7), the magnetic sensors 32 and 42 output the Z-phase pulse signal a plurality of times by setting the magnetic sensors 32 and 42 as described above. Even in this case, only when the steering shaft is in the neutral position, the Z-phase pulse signal is output together.

  Thereby, the AND circuit 5 can output the neutral position signal only when the steering shaft is in the neutral position.

  Therefore, in the host system on the vehicle side, the accurate neutral position of the steering shaft can be detected by determining that the steering shaft is in the neutral position when the AND circuit 5 outputs the neutral position signal. The rotation angle from the neutral position of the steering shaft can be detected based on the A-phase pulse signal and the B-phase pulse signal given from the magnetic sensor 32 thereafter. Regarding the rotation direction, if the A-phase pulse signal is given before the B-phase pulse signal, it is determined that the steering shaft rotates counterclockwise, and the B-phase pulse signal becomes the A-phase pulse signal. If given earlier than this, it can be determined that the steering shaft rotates clockwise.

  Next, a method for assembling the rudder angle detection device 1 will be described. First, the main gear 2 of the rudder angle detection device 1 is fixed to a spiral cable or a steering shaft to be detected. The spiral cable or steering shaft is then rotated to the neutral position. Next, predetermined values of the magnetic sensors 32 and 42 are set so that the magnetic sensors 32 and 42 output a Z-phase pulse signal at this position.

  Here, the predetermined value may be set to a single value, or may be set to a value having a certain range (first angle range, second angle range). When set to a single value, as described above, the magnetic sensors 32 and 42 can output a Z-phase pulse signal only when the spiral cable or the steering shaft is in the neutral position.

  On the other hand, when setting to a value having a certain range, it is desirable to set the predetermined value so that the conditions of the following formulas (10) to (11) are satisfied for the range. This is because if the condition is not satisfied, the magnetic sensors 32 and 42 may output a Z-phase pulse signal multiple times within the steering range of the steering shaft. Here, w1 is an angle at which the steering shaft rotates while the magnetic sensor 32 outputs a Z-phase pulse signal (the steering range of the steering shaft corresponding to the first angle range), that is, the Z of the magnetic sensor 32. The pulse width of the phase. Similarly, w2 is an angle at which the steering shaft rotates while the magnetic sensor 42 outputs a Z-phase pulse signal (the steering range of the steering shaft corresponding to the second angle range), that is, the Z of the magnetic sensor 42. The pulse width of the phase. Further, the denominator ((2 ^ n) * (steering angle detection resolution of the magnetic sensor 32)) of the expression (10) is the period c1 of the magnetic sensor 32, and the denominator ((2 ^ n) * ( The steering angle detection resolution of the magnetic sensor 42)) is the period c2 of the magnetic sensor 42.

w1 <(2 ^ n / x2) * (steering angle detection resolution of the magnetic sensor 32) (10)
w2 <(2 ^ n / x1) * (steering angle detection resolution of the magnetic sensor 42) (11)
Here, if both of the conditions of the above formulas (10) to (11) are satisfied for the range of the predetermined value, the magnetic sensors 32 and 42 output the Z-phase pulse signal only once within the steering range of the steering shaft. Explain why you can.

  That is, the timing at which the magnetic sensor 42 outputs the Z-phase pulse signal during one rotation of the detection gear 3 differs for each period of the magnetic sensor 32. For example, if the magnetic sensor 42 outputs a Z-phase pulse signal when the value of the digital signal of the magnetic sensor 42 is b1, the rotation angle of the detection gear 3 when the value of the digital signal is b1 is magnetic. Different for each cycle of the sensor 32 (see FIG. 5). Here, there are x2 rotation angles of the detection gear 3 corresponding to the timing, and the width between the rotation angles is (360 / x2) [deg]. The rotation angle of the steering shaft corresponding to the width is (c1 / x2) [deg]. The same applies to the magnetic sensor 32.

  Therefore, in order for the magnetic sensors 32 and 42 to output the Z-phase pulse signal only once within the steering range of the steering shaft, the width of the Z-phase pulse signal of the magnetic sensor 32 is at least a cycle c1 of x2. It is necessary to make it smaller than the value obtained by dividing by (condition of equation (10)). Similarly, the width of the Z-phase pulse signal of the magnetic sensor 42 needs to be at least smaller than a value obtained by dividing the period c2 by x1 (condition of equation (11)).

  Therefore, if both of the conditions of the above formulas (10) to (11) are satisfied for the predetermined value range, the magnetic sensors 32 and 42 output both Z-phase pulse signals only when the steering shaft is in the neutral position. Can do.

  In addition, when the steering shaft reaches the neutral position by setting in this way, the magnetic sensors 32 and 42 detect the Z-phase pulse signal while the steering shaft rotates in the overlapping range of the pulse width w1 and the pulse width w2. Can be output together.

  As described above, in the first embodiment, the magnetic sensors 32 and 42 are set to output a Z-phase pulse signal together when the steering shaft is in the neutral position, and the period of the magnetic sensor 32 is set. The number x1 and the period number x2 of the magnetic sensor 42 are relatively prime.

  Therefore, as described above, since the magnetic sensors 32 and 42 can output the Z-phase pulse signal only when the steering shaft is in the neutral position, the AND circuit 5 is provided when the steering shaft is in the neutral position. Only when the neutral position signal can be output.

  Thereby, in the host system on the vehicle side, when the AND circuit 5 outputs the neutral position signal, it is determined that the steering shaft is in the neutral position, so that the accurate neutral position of the steering shaft can be detected.

  In addition, since it is not necessary to run a vehicle or the like on which the steering shaft is mounted in order to detect the neutral position of the steering shaft, the host system on the vehicle side can easily detect the neutral position of the steering shaft.

  Further, the predetermined value of the magnetic sensor 32 can be set to a value having a certain range (first angle range), and the predetermined value of the magnetic sensor 42 has a certain range (second angle range). Can be set to a value.

  Thus, when the steering shaft reaches the neutral position, the magnetic sensors 32 and 42 can output both Z-phase pulse signals while the steering shaft rotates in the overlapping range of the pulse width w1 and the pulse width w2. it can.

  Thereby, for example, even when the steering shaft is slightly deviated from the neutral position (for example, when traveling on a gravel road) while the vehicle equipped with the steering shaft is traveling straight, the AND circuit 5 The neutral position signal can be output.

  Further, since the predetermined values of the magnetic sensors 32 and 42 are variable, changing the predetermined value allows the magnetic sensors 32 and 42 to output both Z-phase pulse signals, that is, when the steering shaft is in the neutral position. The range to be determined can be changed.

  Moreover, since the range of the predetermined value of the magnetic sensors 32 and 42 is set so as to satisfy the above-described formulas (10) to (11), the steering angle detection device 1 is magnetic when the steering shaft is not in the neutral position. It is possible to prevent the sensors 32 and 42 from outputting a Z-phase pulse signal together.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings. First, based on FIGS. 7-8, the structure of the steering angle detection apparatus 1a which concerns on the 2nd Embodiment of this invention and the main functions of each component are demonstrated. 7 is a schematic configuration diagram showing the steering angle detection device 1a, and FIG. 8 is a timing chart showing the output timings of the pulse signals output from the magnetic sensors 22 and 32. As shown in FIG.

  As shown in FIG. 7, the rudder angle detection device 1a is housed in a case (not shown), and includes a main gear (second detection gear) 2, a detection gear (first detection gear) 3, , Magnets 21 and 31, a magnetic sensor (first detection means) 32, a magnetic sensor (second detection means) 22, and an AND circuit (output means) (not shown). Therefore, in the second embodiment, the main gear 2, the magnet 21, and the magnetic sensor 22 play the same role as the detection gear 4, the magnet 41, and the magnetic sensor 42 of the first embodiment. In the following description, the configuration different from that of the first embodiment will be mainly described.

  The main gear 2 rotates integrally with the steering shaft. Therefore, in the present embodiment, the steering range of the steering shaft and the rotation range of the main gear 2 coincide.

  Further, the steering range of the steering shaft is 0 to 2160 [deg] (corresponding to the steering range for three rotations in the left and right directions). The steering range may be another range.

  Since the detection gear 3, the magnet 31, and the magnetic sensor 32 are the same as those in the first embodiment, description thereof is omitted.

  The magnet 21 is provided on the outer peripheral portion of the main gear 2 and rotates together with the main gear 2.

  The magnetic sensor 22 is provided on the moving range of the magnet 21, and generates a pulse signal and outputs it to an AND circuit (not shown) when the magnet 21 passes the magnetic sensor 22. The magnetic sensor 22 can change the width of the pulse signal in the same manner as the magnetic sensor 32. Note that the width of the pulse signal can be changed by changing the shape of the magnet 21.

  An AND circuit (not shown) has a configuration similar to that of the AND circuit 5 in the first embodiment. That is, when both the Z phase of the magnetic sensor 32 and a pulse signal are given from the magnetic sensor 22, the neutral position signal is output to the host system on the vehicle side.

  Here, how the period c1 of the magnetic sensor 32 and the period c3 of the magnetic sensor 22 are set will be described. Here, the period c3 of the magnetic sensor 22 is an angle at which the steering shaft rotates while the main gear 2 rotates once. In the second embodiment, since the main gear 2 and the steering shaft rotate integrally, the period is 360 [deg].

  The periods c1 and c3 are set so as to satisfy the following expression (13) so that the AND circuit can output the neutral position signal only once within the steering range of the steering shaft.

(The least common multiple of c1 and c3) ≧ (steering range of steering shaft) (13)
When the periods c1 and c3 satisfy the condition, the period number x3 of the magnetic sensor 22 and the period number x1 of the magnetic sensor 32 are relatively prime. Here, the cycle number x3 is the number of times the main gear 2 rotates while the steering shaft rotates in the steering range. The number of periods x3 is obtained by the following equation (14). In the second embodiment, since the main gear 2 and the steering shaft rotate integrally, the number of cycles x3 of the magnetic sensor 22 is equal to the number of rotations within the steering range of the steering shaft.

x3 = (the least common multiple of c3 and c1) / c3 (14)
As a result, when the steering shaft is in the neutral position, the magnetic sensors 22 and 32 are set so that the Z phase of the magnetic sensor 32 and the magnetic sensor 22 output both pulse signals, as shown in FIG. The Z-phase and magnetic sensor 22 of the sensor 32 outputs the pulse signal together only when the steering shaft is in the neutral position, even when the pulse signal is output a plurality of times. In FIG. 8, when the steering angle of the steering shaft is a5 [deg], the steering shaft is in a neutral state.

  Therefore, the AND circuit outputs the neutral position signal when both the Z phase of the magnetic sensor 32 and the pulse signal are given from the magnetic sensor 22, and therefore, the neutral position signal is output only when the steering shaft is in the neutral position. It can be output to the host system on the vehicle side.

  Accordingly, the host system on the vehicle side can detect the accurate neutral position of the steering shaft by determining that the steering shaft is in the neutral position when the neutral position signal is output.

  Next, a method for assembling the rudder angle detection device 1a will be described. First, the main gear 2 of the rudder angle detection device 1a is fixed to a spiral cable or a steering shaft to be detected. The spiral cable or steering shaft is then rotated to the neutral position. Next, the positions of the magnetic sensor 22 and the magnet 21 are adjusted and the magnetic sensors 22 and 32 are set so that the Z phase of the magnetic sensor 32 and the magnetic sensor 22 output pulse signals at this position.

  Note that the pulse width of the magnetic sensor 22 and the pulse width of the Z phase of the magnetic sensor 32 can both be changed. However, when the pulse width is increased, these pulse widths can be expressed by the above equations (10) to (11). It is desirable to set the magnetic sensors 22 and 32 so as to satisfy. This is because if the condition is not satisfied, the Z phase of the magnetic sensor 22 and the magnetic sensor 32 may output the pulse signal multiple times within the steering range of the spiral cable or the steering shaft. Here, the pulse width of the magnetic sensor 22 corresponds to w2 in the equation (11).

  By setting in this way, the rudder angle detection device 1a can exhibit the same function as that of the first embodiment.

  As described above, in the second embodiment, the same effects as those of the first embodiment can be obtained, and the following effects can be obtained. That is, since the detection gear 4 and the like in the first embodiment are not necessary, the steering angle detection device 1a can be reduced.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to the drawings. First, based on FIGS. 9-10, the structure of the steering angle detection apparatus 1b which concerns on the 3rd Embodiment of this invention and the main functions of each component are demonstrated. 9 is a schematic configuration diagram showing the steering angle detection device 1b, and FIG. 10 is a timing chart showing the output timing of the pulse signals output from the magnetic sensors 25 and 32. As shown in FIG.

  As shown in FIG. 9, the rudder angle detection device 1b is housed in a case (not shown), and includes a main gear (second detection gear) 2, a detection gear (first detection gear) 3, , A magnetic body 23, magnets 24 and 31, a magnetic sensor (first detection means) 32, a magnetic sensor (second detection means) 25, and an AND circuit (output means) (not shown). Therefore, in the third embodiment, the main gear 2, the magnetic body 23, the magnet 24, and the magnetic sensor 25 have the same roles as the detection gear 4, the magnet 41, and the magnetic sensor 42 of the first embodiment. Fulfill. In the following description, a configuration different from the first and second embodiments will be mainly described.

  The main gear 2 rotates integrally with the steering shaft. Therefore, in the present embodiment, the steering range of the steering shaft and the rotation range of the main gear 2 coincide.

  Further, the steering range of the steering shaft is 0 to 2160 [deg] (corresponding to the steering range for three rotations in the left and right directions). The steering range may be another range.

  Since the detection gear 3, the magnet 31, the magnetic sensor 32, and the AND circuit (not shown) are the same as those in the second embodiment, description thereof is omitted.

  The magnetic body 23 is provided on the outer peripheral portion of the main gear 2 and rotates together with the main gear 2. The magnet 24 is provided in the vicinity of the magnetic sensor 25 in the moving range of the magnetic body 23.

  When the magnetic body 23 passes through the magnetic sensor 25, the magnetic sensor 25 generates a pulse signal and outputs it to an AND circuit (not shown). The magnetic sensor 25 can change the width of the pulse signal in the same manner as the magnetic sensor 32. The width of the pulse signal can be changed by changing the size of the magnetic body 23.

  Further, the period c1 of the magnetic sensor 32 and the period c4 of the magnetic sensor 25 are set to satisfy the above-described conditions (ie, the following) so that the AND circuit can output the neutral position signal only once within the steering range of the steering shaft. The condition of the expression (15) shown) is satisfied. Here, the period c4 of the magnetic sensor 25 is an angle at which the steering shaft rotates while the main gear 2 rotates once. In the third embodiment, since the main gear 2 and the steering shaft rotate integrally, the period is 360 [deg].

(The least common multiple of c1 and c4) ≧ (steering range of steering shaft) (15)
When the periods c1 and c4 satisfy the condition, the period number x4 of the magnetic sensor 25 and the period number x1 of the magnetic sensor 32 are relatively prime. Here, the cycle number x4 is the number of times the main gear 2 rotates while the steering shaft rotates in the steering range. The number of periods x4 is obtained by the following equation (16). In the third embodiment, since the main gear 2 and the steering shaft rotate integrally, the number of cycles x4 of the magnetic sensor 25 is equal to the number of rotations within the steering range of the steering shaft.

x4 = (the least common multiple of c1 and c4) / c4 (16)
Thus, when the steering shaft is in the neutral position, the magnetic sensors 25 and 32 are set so that the Z phase of the magnetic sensor 32 and the magnetic sensor 25 output a pulse signal, as shown in FIG. The Z phase of the sensor 25 and the magnetic sensor 32 outputs the pulse signal together only when the steering shaft is in the neutral position, even when the pulse signal is output a plurality of times. In FIG. 10, when the steering angle of the steering shaft is a5 [deg], the steering shaft is in a neutral state.

  Therefore, the AND circuit outputs a neutral position signal when both the Z-phase of the magnetic sensor 32 and the pulse signal are supplied from the magnetic sensor 25. Therefore, the AND circuit outputs the neutral position signal only when the steering shaft is in the neutral position. It can be output to the host system on the vehicle side.

  Thereby, in the host system on the vehicle side, the accurate neutral position of the steering shaft can be detected by determining that the steering shaft is in the neutral position when the neutral position signal is output.

  Next, a method for assembling the rudder angle detection device 1b will be described. First, the main gear 2 of the rudder angle detection device 1b is fixed to a spiral cable or a steering shaft to be detected. The spiral cable or steering shaft is then rotated to the neutral position. Next, the positions of the magnetic sensor 25, the magnetic body 23, and the magnet 24 are adjusted and the magnetic sensors 25, 32 are set so that the magnetic sensors 25, 32 output a Z-phase pulse signal at this position. .

  Both the pulse width of the magnetic sensor 25 and the Z-phase pulse width of the magnetic sensor 32 can be changed. However, when the pulse width is widened, these pulse widths can be expressed by the above-described equations (10) to (11). It is desirable to set the magnetic sensors 25 and 32 so as to satisfy. This is because if the condition is not satisfied, the Z phase of the magnetic sensor 25 and the magnetic sensor 32 may output the pulse signal multiple times within the steering range of the spiral cable or the steering shaft. Here, the pulse width of the magnetic sensor 25 corresponds to w2 in the equation (11).

  By setting in this way, the rudder angle detection device 1b can exhibit the same functions as those in the first and second embodiments.

  As described above, in the third embodiment, the same effect as that of the second embodiment can be obtained.

  In the first to third embodiments, the main gear 2 is rotated integrally with the steering shaft. However, the main gear 2 may be rotated in conjunction with the steering shaft.

  In the second to third embodiments, a magnet and a magnetic sensor are used to obtain a neutral signal. However, an optical device such as an LED and a light receiving element, or a contact type device may be used. .

It is a schematic structure figure showing a rudder angle detection device of one embodiment of the present invention. It is a block diagram which shows the control system of a rudder angle detection apparatus. It is explanatory drawing which shows the content of the signal output from a magnetic sensor. It is a graph which shows the relationship between the bit number of the digital signal output from a magnetic sensor, and the steering angle detection resolution of a steering angle detection apparatus. It is a characteristic view showing the relationship between the steering angle of the steering shaft and the value of the digital signal output from the magnetic sensor. It is the characteristic view which showed the output timing of the pulse signal output from the Z phase of a magnetic sensor. It is a schematic block diagram which shows the steering angle detection apparatus of other embodiment of this invention. It is a timing chart which shows the output timing of the pulse signal output from a magnetic sensor. It is a schematic block diagram which shows the steering angle detection apparatus of other embodiment of this invention. It is a timing chart which shows the output timing of the pulse signal output from a magnetic sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Steering angle detection apparatus 2 ... Main gear 3 ... Detection gear (1st detection gear)
4. Detection gear (second detection gear)
5. AND circuit (output means)
DESCRIPTION OF SYMBOLS 10 ... Case 21, 24, 31, 41 ... Magnet 32 ... Magnetic sensor (1st detection means)
22, 25, 42 ... magnetic sensor (second detection means)
23 ... Magnetic material

Claims (4)

A first detection gear and a second detection gear that rotate in conjunction with the steering shaft;
First detection means for detecting a rotation angle of the first detection gear, and outputting a detection signal when the detected rotation angle is an angle corresponding to a neutral position of the steering shaft;
Second detection means for detecting a rotation angle of the second detection gear and outputting a detection signal when the detected rotation angle is an angle corresponding to a neutral position of the steering shaft;
An output means for outputting a neutral position signal indicating that the steering shaft is in a neutral position when the first detection means and the second detection means both output the detection signal;
The first detection means and the second detection means output the detection signal together when the steering shaft is in a neutral position, and the number of cycles of the first detection means and the second detection means. A rudder angle detection device characterized in that the number of periods is relatively prime. The rudder angle detection device according to claim 1,
The first detection means outputs a detection signal when the rotation angle of the first detection gear is included in the first angle range;
The second detection means outputs a detection signal when the rotation angle of the second detection gear is included in the second angle range. The rudder angle detection device according to claim 2,
The rudder angle detecting device, wherein the first angle range and the second angle range are variable. In the rudder angle detection device according to claim 2 or 3,
In the first angle range and the second angle range, the steering range of the steering shaft corresponding to the first angle range corresponds to the cycle of the first detection unit and the number of cycles of the second detection unit. The steering range of the steering shaft corresponding to the second angle range is smaller than the angle range obtained by dividing by the above, and the period of the second detection means is divided by the number of periods of the first detection means. The steering angle detection device is set so as to be smaller than the angle range obtained in the above manner.

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