JP2002131049A - Speed reduction mechanism of steering sensor - Google Patents

Abstract

[PROBLEMS] To provide a speed reduction mechanism of a steering sensor which can be reduced in size and cost and which can obtain a high reduction ratio. SOLUTION: This is a speed reduction mechanism of a steering sensor for detecting a steering direction and a steering position of a steering wheel 5, and a worm 2 attached to a steering shaft 1.
A worm wheel 3 that meshes with the worm 2, and a sensor 4 that reads the rotation of the worm wheel 3.
Then, the rotation of the worm wheel 3 is limited to one rotation or less before the steering shaft 1 reaches one rotation limit to the other rotation limit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed reduction mechanism of a steering sensor for detecting a steering direction and a steering position of a steering wheel, and more particularly, to a reduction in size and cost and a high reduction ratio. The present invention relates to a speed reduction mechanism of a steering sensor.

[0002]

2. Description of the Related Art As a steering sensor for detecting a rotational angle position of a steering wheel, for example, Japanese Patent Application Laid-Open
The one disclosed in Japanese Patent Application No. 87558/87 is proposed.

As shown in FIG. 3, such a steering sensor includes a planetary gear 103, a sun gear 104, and a ring gear 10 between a steering shaft 101 and a rotary plate 102.
Through the planetary gear reduction mechanism composed of 5, the rotation plate 102 is configured to make only one rotation until the steering wheel (steering shaft 101) reaches one rotation limit from the other rotation limit.

[0004]

However, in the steering sensor having the above structure, the sensor mechanism itself becomes large in order to obtain a high rotation ratio. For example, the reduction ratio i of this reduction mechanism is as follows: i = −Za / Zc (1) (Za: the number of teeth of the sun gear, Zc: the number of teeth of the ring gear). The steering shaft makes a total of four rotations each of two left and right rotations, and a reduction ratio of 1/4 is required to reduce this to one rotation. Therefore, the ring gear 105 needs at least a diameter four times the diameter of the sun gear 104 (steering shaft diameter) according to the above equation (1). Further, since the rotary plate 102 (sensing unit) is attached to the outer edge thereof, the size of the steering angle sensor is further increased.

Accordingly, an object of the present invention is to provide a speed reduction mechanism of a steering sensor which can be reduced in size and cost and can obtain a high reduction ratio.

[0006]

According to the present invention, there is provided a speed reduction mechanism for a steering sensor for detecting a steering direction and a steering position of a steering wheel, wherein the worm is attached to a steering shaft and meshes with the worm. A worm wheel, and a sensor for reading the rotation of the worm wheel, wherein the rotation of the worm wheel is limited to one rotation or less between the rotation limit of the steering shaft and the rotation limit of the steering shaft. And

According to the present invention, the number of parts can be greatly reduced as compared with the planetary gear reduction mechanism by employing the reduction mechanism composed of the worm and the worm wheel, and the size and cost can be reduced. Further, according to the present invention, since the reduction ratio is determined by the number of worms and the number of teeth of the worm wheel, a high reduction ratio can be obtained without increasing the size.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of a bracket connecting structure according to the present invention will be described below based on an embodiment shown in the drawings.

<Deceleration Mechanism for Steering Sensor> The deceleration mechanism for the steering sensor according to the present embodiment is, as shown in FIG.
A worm wheel 3 meshing with the worm 2, and a sensor 4 for reading the rotation of the worm wheel 3. The worm wheel 3 is driven by the steering shaft 1 from one rotation limit to the other rotation limit. The rotation is within one rotation.

[0010] As shown in FIG. 1, the worm 2 is attached to a steering wheel rotating shaft 6 provided at a base end of a steering wheel 5 fixed to a distal end of the steering shaft 1. It rotates with one.

"Warm wheel" Worm wheel 3
Has an axial angle of approximately 90 degrees, and is arranged so as to mesh with the worm 2 as shown in FIG. As shown in FIG. 2, a plurality of light transmitting portions 7 for reading the rotation of the worm wheel 3 by the sensor 4 are formed at predetermined intervals near the outer peripheral edge of the worm wheel 3.

The worm wheel 3 has an axial angle of 90.
It doesn't have to be the degree.

[Sensor] As shown in FIG. 1, the sensor 4 is arranged so as to sandwich the worm wheel 3, and passes light emitted from the light emitting portion through a light transmitting portion 7 formed on the worm wheel 3. The light receiving section receives light. The arithmetic unit calculates the rotation of the worm wheel 3 based on the on / off data of the light reception, and detects the steering direction and the steering position of the steering wheel 5.

[Deceleration mechanism] In the present embodiment, the rotation of the worm wheel 3 is reduced by one during the period from when the steering shaft 1 reaches one rotation limit to the other rotation limit.
Within the times. For example, if the number of worms 2 is 10,
If the number of teeth of the worm wheel 3 is 40, the rotation of the steering shaft 1 can be reduced to one rotation. At this time, the diameter of the steering shaft 1 is 50 m.
If m, the diameter of the worm wheel 3 is about 20 mm, and the worm wheel 3 can be downsized.

On the other hand, if the planetary gear reduction mechanism of FIG. 3 reduces the speed of four rotations to within one rotation in the same manner as the worm gear reduction mechanism of this embodiment, the diameter of the ring gear 105 needs to be 200 mm or more.

[Operation] As described above, by employing the worm gear reduction mechanism including the worm 2 and the worm wheel 3, the number of parts can be greatly reduced, and the size and cost can be reduced. Further, since the reduction ratio is determined by the number of the worms 2 and the number of teeth of the worm wheel 3, a high reduction ratio can be obtained without increasing the size.

When it is desired to increase the reduction ratio, the number of teeth of the worm 2 can be reduced to 9 or less when the number of worms 2 is 10, or by increasing the number of teeth of the worm wheel 3.

Although the embodiments have been described above, the present invention is not limited to the embodiments, and various modifications accompanying the gist of the configuration of the present invention are possible.

As the sensor 4 for reading the rotation of the worm wheel 3, a conventionally known reading means can be used.

[0020]

As described above, according to the first aspect of the present invention, the number of parts can be greatly reduced as compared with the planetary gear reduction mechanism by employing the reduction mechanism including the worm and the worm wheel. In addition, downsizing and cost reduction can be realized. Further, according to the present invention, since the reduction ratio is determined by the number of worms and the number of teeth of the worm wheel, a high reduction ratio can be obtained without increasing the size.

[Brief description of the drawings]

FIG. 1 is a perspective view of a speed reduction mechanism of a steering sensor according to an embodiment.

FIG. 2 is an enlarged plan view showing a worm and a worm wheel in the speed reduction mechanism of the steering sensor of FIG. 1;

FIG. 3 is a plan view of a conventional steering sensor employing a planetary gear reduction mechanism.

[Explanation of symbols]

 Reference Signs List 1 steering shaft 2 worm 3 worm wheel 4 sensor 5 steering wheel 6 handle rotation axis

Claims (1)

[Claims] 1. A deceleration mechanism of a steering sensor for detecting a steering direction and a steering position of a steering wheel, a worm attached to a steering shaft, a worm wheel meshing with the worm, and a sensor for reading rotation of the worm wheel. A rotation mechanism for the worm wheel, wherein the rotation of the worm wheel is limited to one rotation or less before the steering shaft reaches one rotation limit to the other rotation limit.