JPH0749370Y2 - Steering wheel rotation angle detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of Invention] (Field of Industrial Application) The present invention relates to a steering wheel rotation angle detection device for detecting a rotation angle of a steering wheel with respect to a non-rotating portion.

(Prior Art) In recent years, automobiles have been provided that automatically switch the damping force of the front and rear absorbers to achieve both a comfortable riding comfort and good steering stability. In other words, when the car is going straight, the absorber is set to be soft and the riding comfort is emphasized.When the car changes its course, the absorber is set to be stiff according to the degree of bending and steering stability is emphasized. To do.

In order to realize such an electronically controlled suspension, it is necessary to detect whether the vehicle is going straight or changing the course and give it to the control device as control information. Therefore, as an example of such a device, there is a configuration in which the rotation angle of the steering shaft is detected by a rotary encoder. In this structure, for example, a rotary encoder is provided in the combination switch, and the rotation angle of the steering shaft is transmitted to the rotary encoder by a cam mechanism or a gear mechanism. Therefore,
The rotary encoder rotates according to the rotation angle of the steering shaft, and a pulse signal corresponding to the rotation angle of the steering shaft, that is, the steering wheel is output from the rotary encoder to the control device. The damping force of can be adjusted.

(Problems to be Solved by the Invention) However, in the case of the above-described conventional configuration, since the cam mechanism or the gear mechanism connecting the steering shaft and the rotary encoder has a rattling structure,
There is a drawback that it is difficult to accurately transmit the rotation angle of the steering shaft to the rotary encoder. For this reason, the control timing of the control device deviates from the normal timing, and thus the damping force with respect to the absorber may not be properly adjusted.

Moreover, since the cam mechanism or gear mechanism and the rotary encoder require a large space, there is also a drawback that the combination switch becomes large in size.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a steering wheel rotation angle detection device capable of accurately detecting the rotation angle of the steering wheel while achieving downsizing of the whole.

[Means for Solving the Problem] (Means for Solving the Problems) A rotation angle detection device for a steering wheel according to the present invention has a high reflection portion and a low reflection portion alternately arranged on the bottom surface of the steering wheel with the rotation center of the steering wheel as the center. A thin light and dark pattern portion formed in an annular shape is provided on the non-rotating portion, and a light projecting element that projects light toward the light and dark pattern portion is provided on the non-rotating portion, and the non-rotating portion is reflected by the light and dark pattern portion. A light receiving element for receiving light from the light projecting element is provided (Claim 1).

In addition, a thin resistor pattern portion that is formed in an annular shape around the rotation center of the steering wheel and that generates a voltage according to the distance is provided on the upper surface of the non-rotating portion, and the resistor body is on the same surface as the resistor pattern portion. A thin conductor pattern portion formed concentrically with the pattern portion is provided, and the bottom surface of the steering wheel is brought into sliding contact with the resistor pattern portion and the conductor pattern portion to electrically connect the two pattern portions. A body may be provided (Claim 2).

(Operation) In the case of the steering wheel rotation angle detecting device according to the first aspect, when the steering wheel rotates, the light-dark pattern portion provided on the bottom surface of the steering wheel moves accordingly. Then, since the high-reflecting portions and the low-reflecting portions of the light-dark pattern portion are alternately located at the light-projecting portion from the light-projecting element, the amount of reflected light of the light-dark pattern portion intermittently increases or decreases accordingly. Accordingly, the rotation angle of the steering wheel can be obtained based on the amount of light received by the light receiving element.

In the steering wheel rotation angle detecting device according to the second aspect, when the steering wheel rotates, the sliding contact body provided on the bottom surface of the steering wheel moves accordingly. Then, the positions of the resistor pattern portion and the conductor pattern portion with which the sliding contact body slides move, so that the voltage generated from the resistor pattern portion changes accordingly. Thereby, the rotation angle of the steering wheel can be obtained based on the voltage generated from the resistor pattern portion.

(Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In FIG. 3 in which the column cover is cut away, 1 is a steering shaft, which is rotatably held by the steering column 2. 3 is a combination switch having a turn signal switch and the like, which is mounted on the steering column 2 with the steering shaft 1 penetrating therethrough. A steering shaft 1 projects from the combination switch 3, and a steering wheel 4 is attached to the tip of the steering shaft 1. The steering column 2 and the combination switch 3 are covered with a column cover 5 which is a non-rotating part.

In FIG. 2 showing the upper part of the column cover 5 in a cutaway manner,
The tip of the steering shaft 1 is formed in a conical shape, and a nut (not shown) is screwed into the conical portion 1a with the mounting hole 6a of the steering wheel boss 6 fitted therein, whereby the steering wheel 4 is steered. The shaft 1 is mounted with its central axis aligned.
Here, the combination switch 3 is provided with a tubular portion 7 for canceling a turn signal, and the tubular portion 7 is provided.
The projection 7a formed on the steering wheel 4 is fitted into the hole 6b of the steering wheel boss 6 so that the rotation of the steering wheel 4 is transmitted to the combination switch 3.

Now, the optical sensor 8 is mounted at a predetermined position on the inner peripheral surface of the column cover 5. The optical sensor 8 is composed of a light projecting element 8a and a light receiving element 8b, and the spot light is projected from the light projecting element 8a to the steering wheel boss 6.

In FIG. 1 showing a state in which the steering wheel 4 is removed from the steering shaft 1, an annular thin light-dark pattern portion 9 is attached to the steering wheel boss 6 about the center of rotation of the steering wheel. The bright and dark pattern portion 9 includes a high reflection portion 9a and a low reflection portion 9b.
And are concentrically formed alternately at a predetermined pitch. The steering wheel 4 is the steering shaft 1.
When mounted on the light emitting element 8a, as shown in FIG.
Therefore, the light-dark pattern portion 9 is irradiated with the spot light. With the above configuration, a pulse signal is output from the optical sensor 8 in accordance with the movement of the light and dark pattern portion 9, and the pulse signal is given to a control device (not shown). Then, the control device appropriately adjusts the damping force of the absorber based on the pulse signal from the optical sensor 8, the signal indicating the rotation direction of the steering wheel 4, the speed signal, and the like.

Next, the operation of the above configuration will be described.

When the steering wheel 4 is rotated from the middle position in order to change the direction of the automobile, the light / dark pattern portion 9 moves accordingly.
A pulse signal corresponding to the movement of is output. Then, the control device counts the pulse signals and adjusts the damping force of the absorber to a high value based on the count value and control information such as the speed of the vehicle. Therefore, when the course of the vehicle is changed, the damping force of the absorber is increased, and the maneuverability of the vehicle is improved.

Then, when the steering wheel 4 is returned to the middle position in order to go straight on the automobile, the optical sensor 8 outputs a pulse signal corresponding to the rotation angle thereof, and after the output ends, the pulse signal is not output. The control device determines that the vehicle is traveling straight and adjusts the damping force of the absorber to be low. Therefore, when the vehicle travels straight, the damping force of the absorber decreases, and the riding comfort of the vehicle improves.

In short, according to the configuration described above, the thin and bright pattern portion 9 is provided on the bottom surface of the steering wheel 4, and the optical sensor 8 for detecting the bright and dark pattern portion 9 is provided on the column cover 5 to control the rotation angle of the steering wheel 4. Since the optical sensor 8 is directly detected, the rotation angle of the steering wheel 4 can be accurately detected, unlike the conventional configuration in which the rotation angle of the steering shaft is transmitted to the rotary encoder via the cam mechanism or the gear mechanism. Thus, the damping force of the absorber can be adjusted at precise timing.

Moreover, since the bright and dark pattern portion 9 provided on the bottom surface of the steering wheel 4 is formed thin, it is possible to reduce the overall size, and particularly to reduce the axial direction of the steering shaft 1 in the present embodiment. Even when the rotation angle detection device of 1 is newly provided, the rotation angle detection device can be implemented without significantly changing the conventional structure.

A second embodiment of the present invention is shown in FIGS. 4 to 7. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described. That is, as shown in FIGS. 4 and 6, on the upper surface of the combination switch 3, a thin resistor pattern portion 10 and a slip ring 11 as a conductor pattern portion are concentrically arranged around the rotation center of the steering wheel 4. A variable resistor 12 is provided which is formed. Further, as shown in FIG. 4, a sliding contact body 13 is fixed to the steering wheel boss 6. The sliding contact body 13 has a pair of short-circuited contacts 13a and 13b. When the steering wheel 4 is mounted on the steering shaft 1, as shown in FIG.
The contact 13a is in contact with the resistor pattern portion 10, and the contact 13b is in contact with the slip ring 11. Therefore, since the equivalent circuit of the variable resistor 12 can be shown as in FIG. 7, a voltage signal corresponding to the position of the sliding contact body 13 is given to the control device, which causes the control device to change.
The damping force of the absorber is adjusted based on the voltage signal from.

Also in the second embodiment, the rotation angle of the steering wheel 4 can be directly detected by the voltage generated from the resistor pattern portion 10, so that the control of the absorber by the control device is executed at accurate timing.

Moreover, since the resistor pattern portion 10 and the slip ring 11 arranged on the upper surface of the combination switch 3 are formed thin, the overall size is reduced, especially in the axial direction of the steering shaft 1, as in the first embodiment. Therefore, even if the rotation angle detecting device of this embodiment is newly provided, it can be implemented without significantly changing the conventional structure.

[Advantages of the Invention] As is apparent from the above description, the steering wheel rotation angle detecting device of the present invention has the following advantages.

According to the first aspect, the light and dark pattern portion and the light projecting element and the light receiving element for detecting the light and dark pattern portion are provided on the steering wheel and the non-rotating portion, respectively.
The rotation angle of the steering wheel with respect to the non-rotating portion can be directly detected based on the light receiving state of the light receiving element, and the detection accuracy can be improved. Moreover, since the bright and dark pattern portion is formed thin, the overall size can be reduced.

According to the second aspect of the present invention, the resistor pattern portion and the conductor pattern portion and the sliding contact body that slidably contacts these pattern portions are provided on the non-rotating portion and the steering wheel, respectively. The rotation angle of the steering wheel with respect to the non-rotating portion can be directly detected based on the generated voltage, and the detection accuracy can be improved.
Moreover, since the resistor pattern portion and the conductor pattern portion are formed thin, the overall size can be reduced.

[Brief description of drawings]

1 to 3 show a first embodiment of the present invention,
FIG. 1 is an exploded perspective view showing a state in which a steering wheel is removed from a steering shaft, FIG. 2 is a side view of an essential part shown by breaking a column cover, and FIG. 3 is an entire side view showing a column cover by breaking. It is a figure. FIGS. 4 to 7 show a second embodiment of the present invention. FIG. 4 is a view corresponding to FIG. 1, FIG. 5 is a sectional view of a main part, and FIG. 6 is a resistor pattern. FIG. 7 is a plan view of the part and FIG. 7 is an equivalent circuit diagram of the variable resistor. In the figure, 1 is a steering shaft, 2 is a steering column, 3 is a combination switch (non-rotating portion), 4
Is a steering wheel, 5 is a column cover (non-rotating part), 8 is an optical sensor, 8a is a light emitting element, 8b is a light receiving element, 9
Is a light and dark pattern portion, 10 is a resistor pattern portion, 11 is a slip ring (conductor pattern portion), 12 is a variable resistor, and 13 is a sliding contact body.

Claims (2)

[Scope of utility model registration request] 1. A rotation angle of a steering wheel with respect to a non-rotating portion, the high-reflecting portion and the low-reflecting portion being alternately arranged on a bottom surface of the steering wheel around a rotation center of the steering wheel. A thin light and dark pattern portion formed on the light emitting element, which is provided in the non-rotating portion to project light toward the light and dark pattern portion, and which is provided in the non-rotating portion and reflected by the light and dark pattern portion. A rotation angle detecting device for a steering wheel, comprising: a light receiving element that receives light from a light projecting element. 2. A voltage for detecting a rotation angle of a steering wheel with respect to a non-rotating portion, the voltage being provided in an upper surface of the non-rotating portion and formed in an annular shape about a rotation center of the steering wheel as a center, according to a distance. A thin-walled resistor pattern portion, a thin-walled conductor pattern portion provided on the same surface as the resistor pattern portion and formed concentrically with the resistor pattern portion, and provided on the bottom surface of the steering wheel. A rotation angle detection device for a steering wheel, comprising: a resistor pattern portion and a sliding contact body that electrically contacts the pattern portion by sliding contact with the conductor pattern portion.