JPH068824B2 - Vehicle wind sensor device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a vehicle wind sensor device, and more particularly to a vehicle wind sensor device capable of detecting absolute wind speed and / or absolute wind direction.

[Prior Art] Conventionally, there has been a demand for a wind sensor having a simple configuration for knowing the wind direction, but none of them satisfies the demand.

[Object of the Invention] The present invention has been devised in view of the above circumstances, and an object thereof is to provide an absolute wind speed and / or an absolute wind speed capable of detecting a wind direction with a simple configuration.
Another object is to provide a vehicle wind sensor device capable of detecting the absolute wind direction.

[Configuration of the Invention] A wind sensor of the present invention has a traveling speed detecting means for detecting a traveling speed of a vehicle and / or a direction detecting means for detecting a traveling direction of the vehicle, and a pressure hole opened in a predetermined direction. A plurality of pressure chambers fixed to the vehicle, detection means for respectively detecting the pressure in the pressure chambers, and absolute wind direction and / or wind speed are calculated based on each signal output from each detection means. A wind sensor device for a vehicle, comprising: a calculating unit.

The pressure chamber has a function of converting a fluctuation of a flow velocity component in the specific direction of an air flow flowing in through a pressure hole opened in a specific direction into a fluctuation of a pressure in the pressure chamber.

The piezoelectric conversion means converts the fluctuation of the pressure into an electric signal. This is composed of a diaphragm formed as a part of the wall surface of the pressure chamber and a piezoelectric element attached to the diaphragm. Here, as the piezoelectric element, for example, a semiconductor strain gauge utilizing the piezoresistive effect can be used.

[Examples of the Invention] Hereinafter, the present invention will be described in detail based on specific examples.

1 and 2 show the first embodiment of the wind sensor of the present invention.
It is a partially crushed top view and sectional drawing of an Example. Book first
In the embodiment, the sensor is made compact by stacking the diaphragms.

In this embodiment, as shown in FIG. 2, the pressure chambers 6a to 6d are formed.
Is a separator 2, which is laminated and fixed on the flange 1,
The casing 3 formed by the casing 3 and the diaphragms 4a to 4d and constituting the side walls of the pressure chambers 6a to 6d.
Are provided with pressure holes 7a to 7d in directions orthogonal to each other and communicate with the outside air.

The diaphragms 4a to 4d are made of stainless steel having a diameter of 20 mm and a thickness of 0.05 mm, which can obtain a sufficient amount of strain even at a slight wind speed, and the peripheral edges thereof are fixedly supported by the casing 3 by being tightened together. Furthermore, each diaphragm 4a-4d
Strain gauges 8a to 8d as detection means are bonded to the back side of the, i.e., the central portion on the side not facing the pressure chamber,
The amount of strain of the diaphragms 4a to 4d corresponding to the pressure is detected as an electric signal.

The lead wires of the four strain gauges 8a to 8d are the casing 3
After passing through a hole (not shown) formed in the flange, it is drawn out through a connector 9 attached to the center of the flange 1 and connected to a detection circuit described later.

It should be noted that slits 5 are arranged on the outer periphery of the casing 3 such that the leaves are oriented downward by 45 ° with respect to the horizontal plane. This is to prevent water droplets or the like from entering the sensor.

The sensor of the present embodiment having the above-described structure is manufactured with a response frequency of about 1 kHz, and since it is compact, it can be mounted on the roof of a vehicle or the like.

Next, the principle and operation when the wind sensor having such a configuration is attached to the roof of a vehicle to detect wind from all directions will be described.

3 (a) and 3 (b) are configuration diagrams of an experiment in which the peripheral edge of the diaphragm 4 is fixedly supported and a strain gauge 8 is adhered to the back surface of the diaphragm 4 to change the wind direction θ of the wind W, and graphs showing the results. Is. Here, the horizontal axis of the graph in FIG. 3B represents the wind direction θ [degree], and the vertical axis represents the output level from the strain gauge 8.

As shown by the curve 101, when the wind speed is constant,
If the wind direction θ is determined, the output of the strain gauge 8 is uniquely determined.
Therefore, if the wind sensor is manufactured as described above using the diaphragm having such a fixed characteristic, the wind direction and the wind speed can be obtained from the output of the strain gauge 8.

For example, as shown in FIG. 1, it is assumed that air flows in from the direction of arrow W. The air flow passes through the slit 5 and flows into the pressure holes 7a and 7b. Therefore, the pressure in the pressure chambers 6a and 6b rises, and a positive strain corresponding to the increased pressure causes the diaphragms 4a and 4b in the pressure chambers 6a and 6b to rise.
occur in b. In this case, since the angle θ of the wind direction W is small, the pressure chamber 6a has a higher degree of increase in the above-described degree of increase.
higher than that of b. Therefore, the diaphragm strain is 4a
Is larger than 4b. Therefore, the strain gauge output is 8a.
Is larger than 8b. The wind direction and speed are uniquely determined by comparing the two outputs.

FIG. 4 is a block diagram of a circuit for detecting the wind direction and the wind speed from the output of the window sensor of the first embodiment.

In Figure 4, a Wheatstone bridge by strain gauges 8a and the resistor R ₁ to R ₃ for detecting the pressure in the pressure chamber 6a are formed.

When the input voltage ei is applied to the Wheatstone bridge, the output voltage e ₀ corresponding to the pressure change of the pressure chamber 6a is obtained. Here, the output voltage e ₀ is set to zero level when the pressure chamber 6a is at the reference pressure.

The output voltage e ₀ is amplified by the amplifier 10, and the switch circuit 1
It is output to 1.

Note that, like the circuit A ₁ (circuit within the broken line in the figure),
The output of circuit _A 2 to A ₄ for each strain gauges 8b~8d the other pressure chamber 6a~6d also input to the switch circuit 11.

The switch circuit 11 selects two analog signals relating to the pressure from the diaphragm in which positive distortion has occurred, and the two selected analog signals are input to the A / D converter 12 and converted into digital signals.

The two digitally converted signals are input to the arithmetic / control unit (calculating means in the present invention) 13. The calculation / control section 13
Then, the relative wind speed and wind direction are calculated based on the digital signal. Further, based on the result and the data from the vehicle speed detecting section (vehicle speed detecting means in the present invention) 14 for detecting the vehicle speed and the direction detecting section (direction detecting means in the present invention) 15 for detecting the direction, the absolute value is obtained. The wind direction and wind speed are calculated.

The calculated wind direction and wind speed data are output to and displayed on the instrument panel display unit 16 as shown in FIG.
Further, FIG. 6 is an explanatory view for showing the second embodiment of the present invention, in which correction control for the traveling direction of the vehicle is performed by being output to the actuator 17, and FIG. 7 is a sectional view of the sensor of the second embodiment. It is a figure.

The wind sensor of the first embodiment is installed outside the vehicle to detect wind directions and wind speeds in all directions. However, in the second embodiment, the wind sensor is installed inside the vehicle and the wind direction is within a range of ± 45 ° in the traveling direction of the vehicle.
Detect the wind speed. This is because it is sufficient for steering control to detect only the range as described below.

In FIG. 6, it is assumed that the relative wind W is generated in the vehicle 18 running at high speed. At this time, the pressure applied to the vehicle 18 is represented by the distribution curve 102, and the central portion of the front surface of the vehicle has a positive pressure (+) and both end portions of the front surface have a negative pressure (−). Therefore, as shown by the distribution curve 102, in the case of steering control for cross wind during high speed traveling, it is sufficient if the wind direction detected by the wind sensor is within ± 45 ° with respect to the traveling direction of the vehicle. For this reason, the sensor according to the second embodiment is installed inside the vehicle and guides pressure from the pressure conduits 19 arranged at both ends of the front surface of the vehicle where the pressure difference is the largest to detect the wind speed and the wind direction.

As shown in FIG. 7, in the sensor of the second embodiment, the flanges 21 and 21 ', the casing 22 and the diaphragms 23 and 24, which are laminated in parallel between the flanges 21 and 21' and are fastened together, and the flanges are attached. The strain gauges 25 and 26 are bonded to the diaphragms 23 and 24, respectively. The pressure chamber consists of a flange, casing and diaphragm.
Are formed and communicate with the pressure conduit 19 through passages in the center of the respective flanges 21, 21 '.

As described above, when the steering control is intended, the structure of the window sensor is simpler as described above and can be installed in the vehicle.

FIG. 9 is a sectional view of the sensor of the third embodiment of the present invention.

As shown in FIG. 9, in the third embodiment, four diaphragms 29 are arranged in a mutually orthogonal relationship. When such a configuration is adopted, since the pressure is detected more directly, a window sensor having a good response frequency characteristic can be obtained.

[Effects of the Invention] In summary, according to the present invention, the fluctuation of the wind direction and the wind speed is converted into the fluctuation of the pressure, the fluctuation of the pressure is converted into an electric signal, and the relative wind speed and the relative wind direction with respect to the vehicle thus detected are calculated. A wind sensor device for a vehicle that obtains an absolute wind speed and / or an absolute wind direction by calculation based on a vehicle speed and / or a traveling direction of the vehicle itself.

According to the present invention, regardless of the vehicle speed and traveling direction of the vehicle,
Absolute wind speed and / or absolute wind direction can be detected.

[Brief description of drawings]

FIG. 1 is a plan view of a partially crushed window sensor according to a first embodiment of the present invention, and FIG. 2 is a sectional view thereof. Fig. 3 (a)
Is a configuration diagram of an experimental apparatus for examining the characteristics of the diaphragm, FIG. 3 (b) is a graph showing the relationship between the wind direction θ and the strain gauge output level, and FIG. 4 is the wind direction wind speed using the sensor of the first embodiment. Block diagram of electrical components of the detector, fifth
The figure is a block diagram of the instrument panel display unit. FIG. 6 is an explanatory view showing a usage example of the second embodiment of the present invention, FIG. 7 is a sectional view of the second embodiment, and FIG. 8 is a sectional view of a third embodiment of the present invention. 4, 23, 24, 29 ... Diaphragm 6a to 6d, 27, 28 ... Pressure chamber 8, 25, 26, 31 ... Strain gauge

Claims (1)

[Claims] 1. A traveling speed detecting means for detecting a traveling speed of a vehicle and / or a direction detecting means for detecting a traveling direction of the vehicle, and a pressure hole which opens in a predetermined direction, respectively, and is fixed to the vehicle. A plurality of pressure chambers, a detection unit that detects the pressure in each of the pressure chambers, and a calculation unit that calculates an absolute wind direction and / or wind speed based on each signal output from each detection unit. Characteristic vehicle wind sensor device.