JP4299704B2 - Rotational speed reduction mechanism for steering sensor - Google Patents

Description

  The present invention relates to a rotation speed reduction mechanism for a steering sensor that detects a steering angle of a steering wheel.

FIG. 7 shows a speed reduction mechanism shown in Patent Document 1 as a conventional configuration example of this type of rotation speed reduction mechanism. A worm 2 attached to the steering shaft 1 and a worm wheel 3 meshing with the worm 2 are shown. And a sensor 4 that reads the rotation of the worm wheel 3, and the rotation of the worm wheel 3 is within one rotation until the steering shaft 1 reaches the rotation limit from one rotation limit to the other rotation limit. Yes.
The worm 2 is attached to a handle rotating shaft 6 provided at a base end portion of a steering wheel 5 fixed to the distal end of the steering shaft 1, and rotates together with the steering shaft 1. The sensor 4 is arranged so as to sandwich the worm wheel 3, and the light emitted from the light emitting part is received by the light receiving part through the light transmitting part formed on the worm wheel 3. The rotation of the worm wheel 3 is read based on the above.
JP 2002-131049 A

Incidentally, the rotational speed reduction mechanism shown in FIG. 7 does not have a mechanism for limiting the rotation speed of the steering wheel, that is, the rotation speed of the steering wheel cannot be limited by itself.
Therefore, for example, the steering shaft and the wheels (steering wheels) are not mechanically coupled through a mechanism such as a rack and pinion, and the rotation of the steering shaft to which the steering wheel is attached is electrically detected by a sensor to steer. In the case of a steer-by-wire system configured to actually steer by obtaining the angle and sending the steering angle command value to the steering actuator, the wheel does not have a mechanism for limiting the rotation speed of the steering wheel. It is possible to rotate the steering wheel even after reaching the turning limit, in this case, the steering angle of the wheel does not increase beyond the turning limit, despite the steering wheel turning, As a result, a situation occurs in which the judgment of the relationship between the steering angle of the steering wheel and the turning angle of the wheel is wrong, and safety , A major problem.

  In view of such problems, an object of the present invention is to provide a rotation speed reduction mechanism for a steering sensor having a simple structure that also has a mechanism for limiting the rotation speed of a steering wheel.

  According to the first aspect of the present invention, the rotation reduction mechanism for the steering sensor is attached to the steering shaft, and the steering-side rotation plate having a plurality of spiral grooves centered on the axis thereof formed on the plate surface. A sensor-side rotating plate in which a spiral groove is formed on the plate surface, and the steering-side rotating plate between the steering-side rotating plate and the sensor-side rotating plate. The movable body is inserted into the groove of the sensor-side rotating plate, and the other end is inserted into the groove of the sensor-side rotating plate, and a guide that holds the moving body in the radial direction of the steering-side rotating plate.

  According to a second aspect of the present invention, in the first aspect of the present invention, the moving body has a structure in which a spherical body is rotatably attached to both ends of the rod-shaped body around the axis of the rod-shaped body.

In the present invention, the rotation of the steering side rotating plate is performed through a moving body in which one end is inserted into the multiple spiral groove and the other end is inserted into the single spiral groove of the sensor side rotating plate. Is transmitted to the sensor-side rotating plate, whereby the sensor-side rotating plate can be rotated at a reduced speed, and the rotation number of the steering-side rotating plate is limited by the number of turns of the spiral groove. It has become.
Therefore, according to the present invention, it is possible to realize a rotation speed reduction mechanism for a steering sensor having a simple structure having a mechanism for limiting the rotation speed of the steering wheel.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of the present invention. In this example, a steering-side rotating plate 12 is attached to a steering shaft 11, and the sensor-side rotating plate 13 is partially opposed to the steering-side rotating plate 12. Is arranged.
On the plate surface of the steering side rotating plate 12, spiral grooves (indicated by dots in the figure) 14 centering on the axis of the steering shaft 11 are formed. The number of turns of the spiral groove 14 is as follows. In this example, there are 3 turns (3 rotations). On the other hand, a spiral groove (hatched in the figure) 15 is also formed on the surface of the sensor-side rotary plate 13, and the number of turns of the spiral groove 15 is one (one rotation). Has been.

The sensor-side rotating plate 13 is attached to the rotating shaft 16, and the rotating shaft 16 is parallel to the steering shaft 11 and shifted by a required amount, and the circumferential surface of the sensor-side rotating plate 13 is close to the circumferential surface of the steering shaft 11. Has been.
Thus, the movable body 17 is interposed between the mutually opposing plate surfaces of the steering-side rotating plate 12 and the sensor-side rotating plate 13 that face each other so that one radius portion substantially overlaps. The moving body 17 has a structure in which spherical bodies 17b are attached to both ends of a rod-like body 17a which is a round bar in this example, and one end is inserted into the groove 14 of the steering side rotating plate 12 as shown in FIG. The other end is inserted into the groove 15 of the sensor side rotating plate 13. The spherical body 17b of the moving body 17 is attached to the rod-like body 17a so as to be rotatable around its axis.

  The guide 18 holds the movable body 17 so as to be movable, has a long and narrow block shape, and has a long and narrow guide that is inserted between the opposing plate surfaces of the steering side rotating plate 12 and the sensor side rotating plate 13. A window 19 is formed, and an intermediate portion of the moving body 17 is accommodated in the guide window 19 as shown in FIG. Since the moving body 17 is positioned in the guide window 19 of the guide 18 as described above, the moving body 17 can be moved in the radial direction of the steering side rotating plate 12, and the movement of the moving body 17 in the rotating direction of the steering side rotating plate 12 can be performed. Limited. The other half of the guide 18 is fixed to, for example, a sensor-side housing or the like (not shown).

In the rotation reduction mechanism for a steering sensor having the above-described structure, when the steering side rotating plate 12 rotates, one end is accommodated in the spiral groove 14 and the intermediate portion is accommodated in the guide window 19 of the guide 18. The moving body 17 is moved in the radial direction of the steering side rotating plate 12, and while the steering side rotating plate 12 is rotated by the number of turns of the spiral groove 14, the center portion and the outer peripheral portion of the steering side rotating plate 12 are rotated. Will move between.
Further, since the other end of the moving body 17 is accommodated in the spiral groove 15 of the sensor side rotating plate 13, the sensor side rotating plate 13 rotates with the movement of the moving body 17, and the sensor side rotating plate 13. The number of turns of the spiral groove 15 is 1, so that the moving body 17 moves between the center portion and the outer peripheral portion of the steering side rotating plate 12, in other words, the outer peripheral portion and the center of the sensor side rotating plate 13. While moving between the two parts, the sensor side rotating plate 13 makes one rotation.

  FIG. 4 shows this state, and FIGS. 4A to 4C show how the sensor-side rotating plate 13 rotates every time the steering-side rotating plate 12 makes one rotation from the state shown in FIG. 1A. While the steering side rotating plate 12 rotates once, the sensor side rotating plate 13 rotates 120 °, and when the steering side rotating plate 12 rotates three times, the sensor side rotating plate 13 rotates once. Thus, the rotation speed of the steering side rotating plate 12 is decelerated, and with the rotation of the steering side rotating plate 12, the sensor side rotating plate 13 rotates to make one rotation. FIG. 4D shows the state of FIG. 4C viewed from a direction orthogonal to the axial direction of the steering shaft 11.

When the moving body 17 moves and reaches the start or end of the spiral groove 14, the steering-side rotating plate 12 cannot rotate any further, and therefore the rotational speed of the steering-side rotating plate 12 is spiral. The number of turns in the groove 14 is limited, and in this example, the number of turns is limited to three.
Although the rotation of the sensor-side rotating plate 13 is not particularly shown in the figure, it can be detected by installing a sensor capable of detecting 360 ° rotation on the rotating shaft 16, and thereby the steering angle of the steering wheel can be detected. The absolute angle can be discriminated over the entire rotation limit of the steering wheel. As such a sensor, for example, a sensor having a configuration in which a magnet is attached to the rotating shaft 16 and a 360 ° rotation of the magnet is detected using a plurality of magnetoresistive elements, Hall elements, and the like is used.

According to the rotation reduction mechanism for a steering sensor described above, the number of rotations of the steering shaft 11 can be limited by the number of turns of the spiral groove 14 of the steering side rotating plate 12, that is, the steering wheel The number of rotations can be mechanically limited.
Normally, that is, in the case of a non-steer-by-wire system, the other end of the steering shaft having a steering wheel attached to one end is mechanically coupled to the wheel via a mechanism such as a rack and pinion. The number of rotations of the steering wheel is limited by the limit. Therefore, when the above-described rotation speed reduction mechanism is used, the number of rotations of the steering wheel is limited by two mechanisms.

On the other hand, in the case of the steer-by-wire system, if the rotation reduction mechanism described above is used, the rotation speed of the steering wheel can be limited to a predetermined rotation speed at which the wheel can be steered. It is possible to avoid problems such as misjudgment of the relationship between and the safety in that respect.
In the steer-by-wire system, the steering shaft only needs to be the steering-side rotating plate. Therefore, in this case, the configuration shown in FIG. 5 can be adopted, that is, the rotating shaft 16 of the sensor-side rotating plate 13 is connected to the steering shaft 11. Since the steering side rotating plate 12 and the sensor side rotating plate 13 can be completely opposed to each other, the whole can be made more compact.

In the above-described example, the moving body 17 is configured such that the spherical body 17b is attached to both ends of the rod-shaped body 17a so as to be rotatable around the axis thereof, so that the moving body 17 is smooth in the spiral grooves 14 and 15. However, the moving body 17 is not limited to such a configuration, and may have other configurations.
FIG. 6 shows another configuration example of the moving body together with the moving body 17 described above. In the moving body 21 shown in FIG. 6B, the spherical body 21b is rotatably held at both ends of the plate-like body 21a. In the moving body 22 shown in FIG. 6C, each half of the rod-shaped body 22a has a cylindrical shape, and a cylindrical body 22b whose tip is spherical is rotatable about the axis of the rod-shaped body 22a. It has been attached. The moving body can be a simple rod-shaped body.

  In the example described above, the number of turns of the spiral groove 14 provided on the steering-side rotating plate 12 is three, and the number of rotations of the steering wheel is limited to three. The number of turns of the spiral groove 14 for restriction is appropriately set according to the application. Further, the rotation angle of the sensor-side rotating plate 13 may be arbitrarily set according to the characteristics of the sensor installed on the sensor-side rotating plate 13. Further, the number of turns of the spiral groove 15 of the sensor-side rotating plate 13 is one turn (one turn) in this example. However, the number of turns is not limited to one turn, and may be an arbitrary spiral state of one turn or less. it can.

The figure which shows one Example of the rotation deceleration mechanism for steering sensors by this invention, A is a top view, B is a front view, C is a bottom view. The expanded sectional view of FIG. The perspective view which shows the relationship between the guide in FIG. 1, and a moving body. The figure for demonstrating a mode that the sensor side rotating plate rotates decelerating with rotation of a steering side rotating plate. The figure which shows the other Example of the rotation deceleration mechanism for steering sensors by this invention, A is a top view, B is a front view. The perspective view which shows the various structural examples of a moving body. The perspective view which shows the conventional rotation deceleration mechanism.

Claims (2)

A steering-side rotating plate that is attached to the steering shaft and has a plurality of spiral grooves centered on the axis thereof formed on the plate surface;
A sensor-side rotating plate in which a spiral groove is formed on the plate surface, and the number of turns of the spiral groove is 1 or less;
The steering-side rotating plate and the sensor-side rotating plate are interposed between mutually opposing plate surfaces, one end is inserted into the groove of the steering-side rotating plate, and the other end is inserted into the groove of the sensor-side rotating plate. Moving body,
A rotation decelerating mechanism for a steering sensor, comprising a guide for holding the movable body so as to be movable in a radial direction of the steering side rotating plate. The rotation reduction mechanism for a steering sensor according to claim 1,
A rotating speed reduction mechanism for a steering sensor, wherein the moving body has a structure in which a sphere is attached to both ends of a rod-shaped body so as to be rotatable around the axis of the rod-shaped body.

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