JPH06324060A - Speed measuring apparatus of space filter type and speed controlling system and automobile equipped with the apparatus - Google Patents

Abstract

PURPOSE:To provide a speed measuring apparatus of a space filter type which can obtain correct measuring results in spite of its compact and low-cost structure, and a speed controlling system and an automobile equipped with the measuring apparatus. CONSTITUTION:A speed measuring device 1 is set to a shaft 3 which shows little change in the distance to a road surface 4 while a vehicle 2 is running, so that the distance between the device 1 and the road surface 4 is maintained to be approximately constant. In consequence, a light shielding plate with a small hole formed on the focal plane of a photodetecting lens is eliminated in the device 1, the reflected light from the road surface 4 can be efficiently utilized and a light source part of the device 1 can be made smaller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatial filter type velocity measuring device, a velocity control system including the velocity measuring device, and an automobile.

[0002]

2. Description of the Related Art Conventionally, as a spatial filter type velocity measuring device of this type, there is one disclosed in Japanese Patent Application Laid-Open No. 52-143081. In this device, a light shielding plate having a small hole is arranged on the focal point of the lens between the lens that introduces the reflected light from the object to be measured and the detector. With this configuration, the light introduced into the detector can be limited to the light passing through the focal point of the lens, and the measurement can be performed regardless of the distance between the object to be measured and the detector.
More specifically, when the spatial filter type velocity measuring device is mounted on a vehicle, the distance between the device and the object to be measured is determined by the vehicle posture such as a dive, a squat, a shift squat and a roll as shown in FIG. Fluctuates, which causes a measurement error, but with the above configuration, such a measurement error can be reduced.

[0003]

However, in the spatial filter type velocity measuring device as described above, most of the reflected light from the object to be measured is cut off by the small hole arranged at the lens focal point, and the light receiving element. The rate of reaching to becomes extremely small. In order to eliminate this adverse effect, it is conceivable to increase the amount of light projected onto the measurement object, but in that case, the light source unit such as the LED array becomes large. Furthermore, there is a problem that the cost increases as the size of the light source unit increases. These problems become more prominent particularly when mounted as a vehicle device that requires space saving and low cost.

The present invention solves the above-mentioned problems by providing a device in which the mounting position of the device is such that there is little variation in the distance from the road surface during traveling, and which is excellent in vibration resistance and impact resistance. By doing so, it is an object of the present invention to provide a spatial filter type speed measuring device which can obtain an accurate measurement result, a speed control system including the same, and an automobile, despite being compact and low cost.

[0005]

In order to achieve the above-mentioned object, the invention of claim 1 irradiates light to a measurement object which moves relatively, and receives the reflected light to receive the light, and thereby the measurement object is measured. In the spatial filter type velocity measuring device for measuring the velocity of the vehicle, the device main body is provided at a portion where the distance from the axle of the vehicle or the distance to the road surface during traveling is small. According to a second aspect of the present invention, in a spatial filter type velocity measuring device that measures the velocity of the measurement target by irradiating light to the measurement target that moves relatively and receiving reflected light thereof, The periphery of the light passage space is filled with resin. The invention according to claim 3 comprises the spatial filter type speed measuring device according to claim 1 or 2 and a wheel speed sensor, and the speed is controlled by controlling the brake or the accelerator by the output of these. System. The invention according to claim 4 is an automobile equipped with the speed control system according to claim 3.

[0006]

According to the structure of the first aspect, by providing the speed measuring device at a portion where the distance between the device and the road surface does not fluctuate during traveling of the vehicle, the distance between the device and the road surface is always kept substantially constant. As a result, it becomes unnecessary to provide a light shielding plate having a small hole on the focal plane of the light receiving lens of the device. According to the configuration of claim 2, since the resin is filled except for the portion through which the reflected light from the measurement object passes, the optical components and circuit components in the speed measuring device are fixed by the resin, and the resin is fixed against vibration. Become stronger. In addition, it is also resistant to external vibration and shock. According to the configurations of claims 3 and 4, efficient braking and acceleration can be performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below with reference to FIG. The spatial filter type speed measuring device 1 is attached to the axle 3 of the vehicle 2 and irradiates the road surface 4 with light and receives reflected light to measure the traveling speed of the vehicle 2. Since the axle 3 of the vehicle 2 is a portion unrelated to the spring 5 and the shock absorber 6 which support the vehicle body while vertically moving during traveling of the vehicle 2, the speed measuring device 1 and the road surface 4 are in contact with each other while the vehicle 2 is traveling. The distance is always kept almost constant. The distance between the detection area 4a on the road surface 4 and the surface 4b on which the tire 7 passes should be as short as possible so that the distance between the speed measuring device 1 and the road surface 4 does not change due to the influence of ruts or the like. desirable. The mounting position of the speed measuring device 1 is not limited to the axle 3 of the vehicle 2 and may be provided at a portion of the vehicle 2 where the distance between the speed measuring device 1 and the road surface 4 does not fluctuate during traveling.

As described above, according to the present invention, since the distance between the speed measuring device 1 and the road surface 4 is always kept substantially constant, the shading plate having the small hole in the focal plane of the light receiving lens as in the conventional case. Is not required, and the reflected light from the road surface 4 can be efficiently used. Therefore, the amount of light projected from the speed measuring device 1 to the road surface 4 can be small, the light source unit can be downsized, and the device 1 can be downsized and the cost can be reduced.

Next, a specific structure of the speed measuring device 1 will be described with reference to FIG. The speed measuring device 1 includes an LED 11 that is a light source that irradiates the road surface 4 with light, a light receiving lens 12 that receives the reflected light from the road surface 4, and a photodetector 13 that receives the light introduced through the light receiving lens 12. It is composed of a circuit component 14. Light passing space 1 inside the velocity measuring device 1
The periphery of 5 is filled with resin 16. Since the resin 16 fixes the optical components such as the light receiving lens 12 and the photodetector 13 and the circuit component 14, the vibration resistance and impact resistance of the speed measuring device 1 can be improved.
Further, by filling the resin 16, the heat dissipation effect and the waterproof effect inside the device 1 can be enhanced.

An antilock brake system (ABS) for controlling the brake so as not to lock by using both outputs of the above-mentioned spatial filter type speed measuring device and a wheel speed sensor provided separately, and an accelerator. Traction control system (T
It is also possible to construct a speed control system such as CL).

[0011]

As described above, according to the invention of claim 1,
Since the device body is provided on the axle of the vehicle or at a portion where the distance between the device and the road surface does not fluctuate significantly during traveling, the distance between the device and the road surface can be kept substantially constant. Therefore, unlike the conventional case, it is not necessary to provide a light shielding plate having a small hole on the focal plane of the light receiving lens, so that the reflected light from the road surface can be efficiently used. Therefore, since the amount of light projected can be small, the light source unit can be downsized, the entire device can be downsized, and the cost can be reduced. Further, the current consumption can be reduced, which is economical.
According to the invention of claim 2, since the peripheral portion of the light passage space inside the device is filled with the resin, the vibration resistance and the shock resistance are improved, and the heat dissipation effect inside the device is enhanced. The inside of the device is prevented from becoming extremely hot. Further, since it is filled with resin, the device can have a reliable waterproof structure. From the above, accurate measurement results are obtained,
The reliability of the device is improved. According to the invention of claim 3, since an accurate speed measurement value can be obtained, efficient braking or accelerator control can be performed by this output, and a short braking distance or good acceleration can be expected. . According to the invention of claim 4, since the braking distance is shortened and the acceleration performance is improved, the safety of the automobile is enhanced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a state in which a spatial filter type velocity measuring device according to an embodiment of the present invention is attached to a vehicle.

FIG. 2 is a cross-sectional view showing a configuration of an embodiment of a spatial filter type velocity measuring device.

FIG. 3 is a diagram showing four forms of vehicle attitude.

[Explanation of symbols]

 1 Spatial filter type speed measuring device 2 Vehicle 3 Axle 4 Road surface 15 Light passing space 16 Resin

Claims (4)

[Claims] 1. A spatial filter type speed measuring device for measuring the speed of a measuring object by irradiating a moving object to be measured with light and receiving reflected light from the measuring object. A spatial filter type speed measuring device, characterized in that the speed measuring device is provided on a portion of an axle or a portion of which a distance from a road surface does not fluctuate during traveling. 2. A spatial filter type velocity measuring device which measures the velocity of the measurement target by irradiating light to the measurement target that moves relatively and receiving the reflected light thereof. A space filter type velocity measuring device characterized in that a resin is filled in the peripheral portion of the space. 3. A spatial filter type speed measuring device according to claim 1 or 2, and a wheel speed sensor, wherein the speed is controlled by controlling a brake or an accelerator by the output of these. Speed control system. 4. An automobile equipped with the speed control system according to claim 3.