JPH02210241A - Test device for optical rain sensor - Google Patents

Abstract

PURPOSE:To accomplish desired rainfall speed and rainfall interval by attaching the needle for pseudo rainfall which passes through the optical sensor of an optical rain sensor to a planet gear and making the planet gear rotate and revolve and a sun gear intermittently rotate. CONSTITUTION:The rain sensor 1 which optically detects a raindrop which passes through the optical path is tested by making the needle 21 pass instead of the rain drop. By consecutively rotating an intermittent motor 25 for driving a sun, the planet gear 22 revolves around the sun gear 23 while rotating by a consecutive motor 24 for driving a planet and the tip of the needle 21 draws a locus 30 while moving. The locus 30 of the needle periodically provides a peak 31 and trough 32. When the peak 31 of the locus gets in the optical path of the rain sensor 1, a 'rainy' state is obtained and when the trough 32 is opposed to the sensor 1, a 'fine' state is obtained. Therefore, the state is switched from 'rainy' to 'fine' and from 'fine' to 'rainy' by intermittently rotating the gear 23 by a specified angle, so that the rainfall interval is set the natural number multiple of a revolutional period according to the number of switching times.

Description

[Detailed Description of the Invention] [Summary] A needle for simulating rain that passes through the optical path of an optical raindrop sensor is attached to a planetary gear, and the planetary gear is meshed with a sun gear and rotates to achieve a predetermined rainfall speed. To realize a desired rainfall interval by realizing simulated rain and by intermittently rotating the sun gear.

[Industrial application field]

The present invention relates to an optical rain sensor testing device using a needle for simulated rain.

Since the automatic wiper device of a vehicle automatically changes the operating cycle of the wiper according to the amount of rainfall, a device that detects the amount of rainfall is essential. Since an optical rain sensor optically detects raindrops passing through an optical path and generates a raindrop pulse, the amount of rainfall per unit time can be determined by integrating the pulses in a processing circuit.

[Conventional technology]

FIG. 5 is an example of an optical rain sensor. This sensor 1 constantly receives light from a light emitting section 2 with a light receiving section 3, and when a raindrop passes through a detecting section 4 and the amount of received light decreases, it outputs it as a raindrop pulse.

When this sensor I is shipped, it is necessary to conduct a performance test to determine whether it can accurately detect various rain conditions (particularly light rain conditions).

Figure 6 shows an example of a conventional test device, in which 11 is an AC motor;
12 is a rotating disk driven by the motor, and 13 is a needle for simulating rain that is fixed to the disk and protrudes in the radial direction.

In this device, when the disk 12 rotates once, the needle 13 passes through the optical path of the sensor l once, creating a pseudo state similar to when one raindrop corresponding to the diameter of the needle 13 passes.

[Problem to be solved by the invention]

In the device shown in FIG. 6, when the radius of rotation of the needle 13 is R, the difference between the rain velocity V and the rain interval t is vt=2πR...
・Due to the relationship (1), the rainfall velocity V can be set to a general value (for example, 1
0 m/s), the rain interval is proportional to the radius R, and in order to achieve light rain of t=2 (see), for example, a huge disk 12 is required.

Moreover, in order to realize another rainfall interval t, circle vi12
need to be replaced, which is not practical.

The present invention aims to provide a small-sized rotating simulated rainfall test device that can independently set the rainfall velocity V and the rainfall interval.

[Means to solve the problem]

Figure 1 is a diagram of the principle of the present invention, where 21 is a needle for simulated rain;
2 is a planetary gear with the number of teeth Zp and radius Rp from which the cough needle is fixed and protrudes in the radial direction, and 23 is the number of teeth Z that meshes with the planetary gear.
s, a sun gear with a radius Rs; 24, a continuous planetary drive motor such as an AC motor that continuously rotates the planetary gear 22;
25 is an intermittent motor for driving the sun, such as a stepper motor, which shifts the trajectory of the needle 21 in the circumferential direction by intermittently rotating the sun gear 23 by a predetermined angle; 26 is a planetary revolution axis; 27 is a planetary rotation axis; 28 is a planetary rotation axis; The frame 29 linking both axes is the solar rotation axis.

[Effect]

When the motor 25 is continuously rotated, the planetary gear 22 revolves around the sun gear 23 while rotating.

As a result, the tip of the needle 21 moves while drawing a trajectory 30 as shown in FIG. A feature of this locus 30 is that it has periodic peaks 31 and valleys 32 because the planetary gear 22 is rotating. When the peak 31 enters the optical path of the rain sensor l as shown in FIG. When the rain sensor 1 faces the rain sensor 1, it becomes a "sunny" state.

The sun gear 23 sets the rain interval t by switching between the "rainy" and "sunny" states. Second
In the example shown, the gear ratio Z s / Z p = 4, so peaks 31 and valleys 32 appear alternately every 45''. Therefore, the sun gear 23 is rotated by 45 degrees in the direction of revolution of the planetary gear 22. It switches from "rain" to "sunny" and from "sunny" to "rain" every time, and depending on the number of switches, the rain interval t is changed to the orbital period t.
It can be set to a natural number N times p. In other words, the second
If the planetary gear 22 is made to revolve (N-1) times in the "sunny" state of FIG. After the rotation and revolution, the sun gear 23 is further rotated by 45 degrees, and then the planet teeth 22 are made to revolve again (N to 1 times) in the "clear" state as shown in (b).

By repeating these operations, the rainfall interval t can be reduced to t=N-jp...
(2) can be set.

In the above equation, N=1 is the state shown in FIG. 2(a), and at this time the sun gear 23 is kept stationary. The rotation of the sun gear 23 is necessary only at N22, and if this is done while the planetary gear 22 is in range A in FIG. 2(b), an unstable state can be avoided.

The speed at which the needle 21 crosses the optical path of the rain sensor 1 in the "rain" state (
Rainfall speed) (3) is expressed as (3), where Rr is the length from the rotation axis of the planetary gear 22 to the tip of the needle 21. - As an example, t = 0.25 (sec
).

R5=100 (mm), Rp=25 (man
), when Rr=55 (mud), v = i 0. l (m/s), which is the standard rainfall speed. At this time, the outer diameter of the device is at most Rs + Rp + Rr -18 (mm), so it can be much smaller than R = 3.2 [m] in Fig. 6.

〔Example〕

FIG. 3 is a perspective view showing an embodiment of the present invention.

In this example, the frame 28 that links the rotation axis 27 and the revolution axis 26 of the planetary gear 22 is triangular, and in addition to the planetary gear 22 to which the needle 21 is fixed, there are two planetary gears 41 for stabilizing the revolution.
．． 42 was added.

A slit plate 43 is fixed to the planetary revolution shaft 26, and by detecting the slit 44 with a photo ink clubter 45, the revolution position of the needle 21 is determined, and the rotation timing of the sun gear 23 is determined. .

The rain sensor 1 is placed on the sensor holder 46 and tested. An AC motor is used as the planetary drive motor 24, and a stepper motor is used as the sun drive motor 25.

In this example, Z s / Z p = 100 as shown in Figure 2.
/25=4, but this can also be a different value (an integer). Figure 4(a) shows Z s / Z p
= 3, and (b) is Z s / Z
This is an example where p = 5.

Mountains 31 in the locus that occur per revolution period of the planetary gear 22
and the number of valleys 32 are each equal to the tooth number ratio Z s / Zp, so the larger Z s / Z p is, the more “rainy” and “sunny” it is.
The rotation angle of the sun gear 23 for switching can be small. On the other hand, as Z s / Z p becomes larger, the difference between the peak 31 and the valley 32 decreases, so it becomes difficult to distinguish between "sunny" and "rainy". The value of Z s / Z p must be selected from these considerations.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to downsize a simulated rain test device for an optical rain sensor, and there is an advantage that the rain interval can be varied while keeping the rain speed constant.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is an explanatory diagram of the operation of the present invention, Fig. 3 is a perspective view showing one embodiment of the invention, and Fig. 4 is an explanation showing another example of the tooth number ratio. 5 is a block diagram of an optical rain sensor, and FIG. 6 is a block diagram of a conventional simulated rain test device. Applicant Fujitsu Ten Ltd. Representative Patent Attorney Minoru Aoyagi Figure 2 - 1Zs/Zp=3 tbl zs/Zp=5 (a) Front view, etc.) Perspective view Configuration diagram of optical rain sensor Configuration of conventional test equipment Figure 6

Claims (1)

[Claims] 1. A rain sensor that optically detects raindrops passing through an optical path (
In an optical rain sensor test device for testing the performance of 1) by passing a needle (21) instead of the raindrop, the planetary gear (22) has the needle (21) protruding in the radial direction.
a sun gear (23) that meshes with the planetary gear (22); a continuous planetary drive motor (24) that rotates the planetary gear (22) continuously; A testing device for an optical rain sensor, comprising: a solar drive intermittent motor (25) that shifts the locus (30) of the needle (21) in the circumferential direction by rotating the needle (21) by a predetermined angle.