JP4569044B2 - Rotation angle detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multi-rotation steering wheel rotation angle detection device used in an automobile body control system.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a rotation angle detection device that detects a rotation angle of a rotating body that rotates finitely more than one rotation, such as an automobile handle, is known as disclosed in JP-T-11-500828. . In this apparatus, the rotation angle is detected from the angle of two rotating bodies having a phase difference.
[0003]
[Problems to be solved by the invention]
However, in the above apparatus, when the angles of the two gears are shifted due to the rattling of the gears, a large measurement error may occur particularly at the start of the operation of the apparatus. I can't do that.
[0004]
The present invention intends to provide an accurate rotation angle detection device that suppresses gear rattling with a simple mechanism.
[0005]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention has a first rotating body having a first gear which is capable of multiple rotations, and a second gear engaged with the first gear of the first rotating body. A second rotating body that rotates at a higher speed than the first rotating body; a first rotation angle detecting unit that detects a rotation angle of the second rotating body; and the second rotating body. A third rotating body having a fourth gear engaged with the third gear and rotating at a lower speed than the first gear, and a second rotation for detecting a rotation angle of the third rotating body. The angle detection means, the meshing between the first gear of the first rotating body and the second gear of the second rotating body, and the third gear of the second rotating body And the fourth gear of the third rotating body includes a rattling absorbing means for absorbing one or both of the rattling, and the first rotation The angle detection means and the second rotation angle detection means are configured to detect the rotation angle of the first rotating body, and the meshing of the gear transmission system is eliminated to prevent the first rotating body from rotating. The rotation can be faithfully transmitted to the second and third rotating bodies, and a highly accurate rotation angle detection mechanism is provided.
[0006]
A second aspect of the present invention provides an accurate rotation angle detection system using an AMR element as the rotation angle detection means in the first aspect of the present invention.
[0007]
According to a third aspect of the present invention, in the first or second aspect of the present invention, as the meshing rattling absorbing means, a pressing force that applies a pressing force in a direction to reduce the interval between the respective rotating shafts of the meshing gears. It has a generating means, so that the meshing of the gears can be effectively taken.
[0008]
According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the meshing rattling absorbing unit has a rotational force imparting unit that constantly imparts a rotational force to at least one of the meshing gears. Therefore, the meshing of the gears can effectively take the rattling.
[0009]
The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the second gear provided on the first gear and the second rotor of the first rotor. Is a combination of a spur gear or a helical gear, and the third gear provided on the second rotating body and the fourth gear provided on the third rotating body are worms. The worm wheel or worm is a combination of helical gears, and has the advantage that the speed increasing portion and the speed reducing portion can be configured in a compact manner.
[0010]
The invention according to claim 6 is the invention according to claim 3, wherein the pressing force generating means is a leaf spring, and the pressing force generating means can be realized at low cost.
[0011]
According to a seventh aspect of the present invention, in the invention of the fourth aspect, the rotational force applying means is realized by a helical torsion spring, and the pressing force generating means can be realized at low cost.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
FIG. 1 shows a plan view of Embodiment 1 of the rotation angle detection device of the present invention, FIG. 2 shows a front view thereof, and FIG. 3 shows a side view thereof. FIG. 4 explains Embodiment 1 of the rotation angle detection device of the present invention. FIG. 5 shows a plan view of the state with the cover of FIG. 1 removed, and FIG. FIG. 6 shows a side view in which a part of FIG. 3 is cut so that the structure of the main part can be seen.
[0013]
7 is a plan view showing only the arrangement of the gear coupling mechanism, magnet and AMR element in FIG. 4, FIG. 8 is a front view of FIG. 7, and FIG. 9 is a side view of FIG.
[0014]
In FIGS. 1 to 3, 1 is a case as a fixed body attached to a steering section of a vehicle or the like, 2 is a first rotating body having gears on the entire circumference, and its cylindrical hub 2a is visible. In addition, a through hole 2b is formed at the center of the first rotating body 2, but has projecting engagement portions 3a and 3b on the side surfaces thereof. For example, a shaft (not shown) of the steering unit passes through the hole 2b and is engaged with the rotation direction by the engaging units 3a and 3b, and transmits the rotation of the steering unit to the first rotating body 2. Reference numerals 4a and 4b denote holes for positioning when the rotation angle detection device of the present invention is attached to a steering part (not shown). Reference numeral 5 denotes a connector for transmitting and receiving signals.
[0015]
In FIG. 4 to FIG. 6, the internal structure is easy to see through the lid. Reference numeral 1 denotes a case as a fixed body attached to a steering section of a vehicle or the like, and 2 denotes a first rotating body having a first gear 2c on the entire circumference, and is rotatably fitted in the guide hole 1a of the case 1 Has been. Reference numeral 6 denotes a second rotating body, which includes a second gear 6a that engages with the first gear 2c of the first rotating body 2 and a worm 6b that is a third gear. The bearings 7 and 8 are guided to rotate freely and are lightly pressed by a leaf spring 9 as a gear pressing means. Reference numeral 10 denotes a third rotating body, which has a fourth gear 10a that meshes with a worm 6b that is a third gear, and is fitted to a bearing portion (not shown) provided in a part of the case 1. It can be rotated. The third rotating body 10 is set such that the torsion coil spring 11 generates a rotational force in the right rotation direction or the left rotation direction.
[0016]
In FIGS. 7 to 9, only the rotation system is taken out and the relationship of the rotation angle measurement is explained in an easy-to-understand manner. A magnet 12 is attached to the rotation shaft portion of the second gear 6a of the second rotating body 6 with the magnetic pole direction aligned with the radial direction (see FIG. 10). Further, an AMR element (anisotropic magnetoresistive element) 13 is attached to a printed circuit board 14 at a distance of about 1 mm from the magnet 12. Further, a magnet 15 is attached to the rotation shaft portion of the third rotating body 10 with the magnetic pole direction aligned with the radial direction (see FIG. 11). Further, an AMR element (anisotropic magnetoresistive element) 16 is attached to a printed circuit board 17 at a distance of about 1 mm from the magnet 15. The AMR element periodically outputs a signal of 1 V to 4 V, for example, every time the corresponding magnet rotates 180 degrees. For example, when the second rotating body 6 is set to be accelerated four times as much as the first rotating body 2 and the third rotating body 10 is decelerated to 1/48 relative to the second rotating body 6. The third rotating body 10 is decelerated to 1/12 with respect to the first rotating body 2. This means that when the first rotating body 2 rotates 6 times, the second rotating body 6 rotates 24 times, and the third rotating body 10 rotates 1/2 times (that is, 180 degrees).
[0017]
The AMR element outputs a signal of one cycle every time the magnet rotates 180 degrees. When the first rotating body 2 rotates from the neutral position to the right at a constant rotational speed, the AMR element 13 receives a signal from FIG. ), Every time the first rotating body 2 rotates 45 degrees, for example, 1V to 4V sawtooth signals S ₁ , S ₂ ... Are repeatedly generated a total of 12 times. 12 S ₀ rotary member 2 gradually voltage rises beginning first of, for example, 2.5V as the curve reaches 4V in was 3 rotates (1080 ° rotation) of (b). In the left rotation, the voltage changes as shown in FIGS.
[0018]
The signal of the AMR element 16 changes only gradually with respect to the rotation of the first rotator 2 and therefore cannot give a fine value, but the absolute angle of the first rotator 2 is approximately how many times the rotation. It is possible to know from an overall perspective. Since the signal from the AMR element 13 is shown by enlarging the narrow angle range of the first rotating body 2 as shown in FIG. 12A, angle measurement with high accuracy can be performed.
[0019]
By using the signals of both the AMR element 13 and the AMR element 16, it is possible to measure with high accuracy such as a resolution of 0.1 degree over the entire range of six rotations of the first rotating body 2. Specifically, when the signal of the AMR element 16 indicates a point P _0, for example, the AMR element 16 indicates the P ₁ point in the signal S ₁ with high accuracy, and the first rotating body 2 performs accurate measurement over 6 rotations. Can do. The AMR element detects the direction of the magnetic lines of force of the magnet, and even when the measuring system is turned on, the direction of the magnet, that is, the angular position of the rotating body can be measured as an absolute value. It is completely unaffected by moving the rotating body when the power is off.
[0020]
In the rotation angle detection device of the first embodiment, the second gear 6 a of the second rotating body 6 is lightly pressed by the first gear 2 c of the first rotating body 2 by the leaf spring 9. Therefore, the teeth are engaged with each other without backlash, and even when the rotation direction is switched, the rotation is transmitted without backlash or delay, and the measurement accuracy is high. Further, for example, a torsion coil spring 11 is urged in the rotational direction between the fourth gear 10a and the case 1 on the fourth gear 10a of the third rotating body 10, and the fourth gear is generated by the rotational torque. The teeth of 10a lightly press the teeth of the worm 6b of the second rotating body 6 in the direction of the axis of rotation. Again, the backlash between the gears is absorbed and the rotation of the second rotating body 6 does not rattle and is accurate. To the third rotating body 10.
[0021]
A large backlash between the third gear 6b and the fourth gear 10a, worsens the signal accuracy of S _0, for example, point P ₁ is sweet, S ₁ and S signals of the AMR element 13 There is a possibility of mistaken for ₂ and displaying the wrong angle. The inaccuracy of the gear transmission is also caused by the movement of the second rotating body 6 and the third rotating body 10 in the axial direction, but in the first embodiment, the third rotating body 10 has its torque. Thus, the second rotating body 6 is urged in the axial direction so as to have a shakiness in the axial direction, and the third rotating body 10 itself also gives the torsion coil spring 11 the function of a compression spring, or the axial center. Shaking in the axial direction can be achieved by inserting a leaf spring (not shown).
[0022]
FIG. 13 shows the detailed pressure contact of the leaf spring 9. The shaft portion of the second rotating body 6 is biased toward a direction R substantially in the middle between the perpendicular direction N of the wall surface 7 a of the bearing portion 7 and the central direction Q of the first rotating body 2 by the pressing force of the leaf spring 9. As a result, the rotation center of the second rotating body 6 is determined as one point in both the left and right rotation directions, and the second rotation body 6 can be rotated with high accuracy. The wall surface 7a is substantially in the Q direction. The plate spring 9 may not be plate-shaped but may be a compression spring or a tension spring, as long as the second rotating body 6 can be urged in the R direction. The torsion coil spring 11 may be anything as long as it can give torque to the third rotating body 10. Further, the same effect can be obtained by using either one of these methods or by mixing these gears.
[0023]
【The invention's effect】
As described above, in the present invention, the rotation angle measurement using the AMR element and the magnet is performed by the acceleration detection unit and the deceleration detection unit with respect to the shaft to be measured, and the rattling of the gear accompanying the acceleration and deceleration is performed. This makes it possible to provide a rotation angle detection device capable of detecting an absolute angle position with high accuracy over a wide range of multiple rotations, and to provide advanced information that contributes to vehicle attitude control, etc. Is something that can be given.
[Brief description of the drawings]
FIG. 1 is a plan view showing a first embodiment of a rotation angle detection device of the present invention. FIG. 2 is a front view of the rotation angle detection device. FIG. 3 is a side view of the rotation angle detection device. FIG. 5 is a front view of the same part cutout. FIG. 6 is a side view of the same part cutout. FIG. 7 shows only the gear coupling mechanism, the arrangement of the magnet and the AMR element. FIG. 8 is a front view thereof. FIG. 9 is a side view of the same device. FIG. 10 is a plan view showing a directional relationship between a second rotating body and magnetic poles of the magnet. FIG. 12A is a waveform diagram showing an angle signal obtained from the AMR element 13 in the apparatus, and FIG. 12B is an angle signal obtained from the AMR element 16 in the apparatus. Waveform diagram [Fig. 13] The second rotating body of the device is a leaf spring. Enlarged view showing a pressurizing state EXPLANATION OF REFERENCE NUMERALS
DESCRIPTION OF SYMBOLS 1 Case 2 1st rotary body 3a, 3b Projection-like engagement part 4a, 4b Hole 5 Connector 6 2nd rotary body 7 Bearing part 8 Bearing part 9 Plate spring 10 3rd rotary body 11 Torsion coil spring 12 Magnet 13 AMR element 14 Printed circuit board 15 Magnet 16 AMR element 17 Printed circuit board

Claims (7)

A first rotating body that is capable of multiple rotations and has a first gear, and a second gear that engages with the first gear of the first rotating body, and that is faster than the first rotating body. A second rotating body that rotates, a first rotation angle detecting means that detects a rotation angle of the second rotating body, and a fourth gear that engages with a third gear provided on the second rotating body. A third rotating body that rotates at a lower speed than the first rotating body, a second rotation angle detecting means that detects a rotation angle of the third rotating body, and the first rotation The meshing between the first gear of the body and the second gear of the second rotating body, the third gear of the second rotating body and the third rotating body of the third rotating body. A meshing absorbing means for absorbing one or both of the meshing with the fourth gear is provided, and the first rotational angle detecting means and the front Rotation angle detection apparatus characterized by being configured to detect the rotation angle of said first rotary member by a second rotation angle detecting means. A rotation angle detection apparatus using an AMR element in one or both of the first rotation angle detection means and the second rotation angle detection means. The rotation angle detecting device according to claim 1 or 2, wherein the meshing absorption means includes a pressing force generating means for applying a pressing force in a direction to reduce the interval between the rotating shafts of the meshing gears. . The rotation angle detecting device according to claim 1, wherein the meshing and absorbing means includes a rotational force applying unit that constantly applies a rotational force to at least one of the meshing gears. The first gear of the first rotating body and the second gear provided on the second rotating body are a combination of a spur gear or a helical gear, and are provided on the second rotating body. 5. The third gear and the fourth gear provided on the third rotating body are a combination of a worm and a worm wheel or a helical gear. The rotation angle detection apparatus in any one of. The rotation angle detecting device according to claim 3, wherein the pressing force generating means is a leaf spring. The rotation angle detecting device according to claim 4, wherein the rotational force applying means is a helical torsion spring.

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