WO2017017903A1

WO2017017903A1 - Vehicle collision detection device

Info

Publication number: WO2017017903A1
Application number: PCT/JP2016/003194
Authority: WO
Inventors: 皓太天野; 田辺　貴敏; 大祐中根; 吉田　智一; 和久橋本
Original assignee: 株式会社デンソー
Priority date: 2015-07-28
Filing date: 2016-07-05
Publication date: 2017-02-02
Also published as: JP6323722B2; JP2017024685A; DE112016003398T5

Abstract

A vehicle collision detection device comprises: a detection tube member (2) having a hollow section (2a) formed in the interior thereof; a pressure sensor (3) that detects the pressure within the hollow section; and a collision detection unit that detects a collision of a physical object with a bumper on the basis of the pressure detection results from the pressure sensor. The pressure sensor has a sensor body (30) provided with a sensing unit (31), and a pressure introduction tube (32) for introducing pressure into the sensor body. The pressure introduction tube is inserted into the inner side of an end section of the detection tube member and introduces the pressure within the hollow section into the sensor body. The pressure introduction tube is provided with a deceleration section (321) for reducing the propagation velocity of pressure waves generated within the hollow section as a result of a collision.

Description

Vehicle collision detection device

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2015-148701 filed on July 28, 2015, the contents of which are incorporated herein by reference.

The present disclosure relates to a vehicle collision detection device for detecting a collision with a pedestrian or the like of a vehicle.

Conventionally, there are vehicles equipped with a pedestrian protection device for reducing the impact on the pedestrian when the pedestrian collides with the vehicle. In this vehicle, a bumper unit is provided with a collision detection device, and when this sensor detects that a pedestrian or the like has collided with the vehicle, the pedestrian protection device is activated to reduce the impact on the pedestrian. . An example of a pedestrian protection device is a pop-up hood. The pop-up hood raises the rear end of the engine hood when a vehicle collision is detected, increases the clearance between the pedestrian and hard parts such as the engine, and absorbs collision energy to the pedestrian's head using that space. And reduce the impact on the head.

In the above-described vehicle collision detection device, a chamber member having a chamber space is disposed in front of a bumper reinforcement in the bumper of the vehicle, and the pressure in the chamber space is detected by a pressure sensor. There is something. When an object such as a pedestrian collides with the bumper cover, the chamber member is deformed with the deformation of the bumper cover, and a pressure change is generated in the chamber space. The pressure sensor detects this pressure change to detect a pedestrian collision.

In recent years, a tube-type vehicle collision detection device that detects a collision using a tube member that is smaller and more easily mounted than the above-described chamber-type vehicle collision detection device has been proposed. This vehicle collision detection device includes a bumper absorber disposed in a bumper of a vehicle, a hollow tube member mounted in a groove formed in the bumper absorber along the vehicle width direction, and a pressure in the tube member. A pressure sensor to detect, and a collision detection unit to detect occurrence of a collision based on a pressure detection value detected by the pressure sensor. When a pedestrian or the like collides with the front of the vehicle, the bumper absorber is deformed while absorbing the impact, and at the same time, the tube member is also deformed. At this time, the pressure in the tube member rises, and this pressure change is detected by the pressure sensor. A collision detection part detects the collision with the pedestrian of a vehicle based on the pressure detection value by a pressure sensor.

Special table 2014-505629

Here, the pressure sensor used in the above-described vehicle collision detection device includes a sensor main body provided with a sensing unit for pressure detection, and a pressure introduction pipe for introducing pressure into the sensor main body. . The pressure introducing tube is inserted inside the end of the detection tube member, and introduces the pressure in the tube member into the sensor body.

A pressure wave is generated in the tube member with a collision with a pedestrian or the like of the vehicle, and the pressure wave propagates from the tube member to the sensor body through the pressure introducing pipe. At this time, the amplitude of the pressure wave detected by the sensing unit may increase due to an increase in the propagation speed of the pressure wave. In this case, the pressure output from the pressure sensor is mixed with a negative value (that is, the pressure value when the pressure decreases), or the pressure wave accuracy is large, which affects the accuracy of the pressure value acquired by the collision detection unit. There is a problem that it is necessary to improve collision detection accuracy.

This disclosure is intended to provide a vehicle collision detection device that improves the accuracy of collision detection by adjusting the output of a pressure sensor at the time of a collision.

In one aspect of the present disclosure, a vehicle collision detection device includes a detection tube member that is disposed in a bumper of a vehicle and has a hollow portion formed therein, and a pressure that detects a pressure in the hollow portion of the detection tube member. A sensor, and a collision detection unit that detects a collision of an object with the bumper based on a pressure detection result by the pressure sensor. The pressure sensor has a sensor main body provided with a sensing unit for pressure detection, and a pressure introduction pipe for introducing pressure into the sensor main body. The pressure introducing tube is inserted inside the end of the detection tube member to introduce the pressure in the hollow portion into the sensor body. The pressure introducing pipe has a speed reducing portion that reduces the propagation speed of the pressure wave generated in the hollow portion due to the collision.

According to this configuration, the velocity of the pressure wave detected by the sensing unit is reduced by reducing the propagation speed of the pressure wave generated in the hollow part due to the collision by the speed reducing unit provided in the pressure introduction pipe of the pressure sensor. Can be small. Thereby, it can suppress that a negative value is mixed with the pressure detection value from a pressure sensor, and the pressure detection value output from a pressure sensor can be correctly acquired by a collision detection part. Therefore, the collision detection accuracy of the vehicle collision detection device can be improved.

1 is a diagram illustrating an overall configuration of a vehicle collision detection device according to a first embodiment. It is an enlarged view of the bumper part of FIG. FIG. 3 is a III-III cross-sectional view of the bumper portion of FIG. 2. It is sectional drawing which shows the internal structure of a pressure sensor. It is a graph which shows the waveform of the pressure wave which arises with a collision. It is a graph which shows the waveform of the pressure wave in a reference example. It is sectional drawing which shows the internal structure of the pressure sensor in 2nd Embodiment. FIG. 8 is a VIII-VIII cross-sectional view of the pressure introducing pipe of FIG. It is sectional drawing which shows the internal structure of the pressure sensor in 3rd Embodiment. FIG. 10 is a cross-sectional view of the pressure introducing pipe of FIG. 9 taken along the line XX.

[First Embodiment]
A vehicle collision detection apparatus according to a first embodiment will be described with reference to FIGS. As shown in FIGS. 1 and 2, the vehicle collision detection device 1 of this embodiment includes a hollow detection tube member 2, a pressure sensor 3, a speed sensor 4, a collision detection ECU 5 (corresponding to a collision detection unit), and the like. It is prepared for. The vehicle collision detection device 1 detects a collision of an object (that is, a pedestrian or the like) with a bumper 6 provided in front of the vehicle. As shown in FIG. 3, the bumper 6 is mainly composed of a bumper cover 7, a bumper absorber 8, and a bumper reinforcement 9.

As shown in FIGS. 1 and 2, the detection tube member 2 is a tube-shaped member having a hollow portion 2a formed therein and extending in the vehicle width direction (that is, the vehicle left-right direction). The tube member 2 for detection is arrange | positioned in the bumper 6 of a vehicle in the position facing the front surface 9a of the bumper reinforcement 9, ie, the vehicle front side. Both ends of the tube member for detection 2 are curved on the left and right outer sides of the bumper reinforcement 9 in the vehicle width direction and connected to a pressure sensor 3 described later.

As shown in FIG. 3, the tube member for detection 2 has a circular cross-sectional shape and is made of synthetic rubber, for example, silicone rubber. The outer diameter of the detection tube member 2 is about 7 mm to 10 mm. Further, the thickness of the peripheral wall of the detection tube member 2 is about 1 mm to 3 mm. In this embodiment, the outer dimensions of the detection tube member 2 are set to an outer diameter of 8 mm and a wall thickness of 2 mm. The material of the detection tube member 2 may be ethylene propylene rubber (EPDM) or the like.

1 and 2, the pressure sensor 3 is disposed on the vehicle rear side of the front surface 9a of the bumper reinforcement 9. Specifically, two pressure sensors 3 are installed on the left and right ends of the bumper cover 7, and are fixedly attached to the rear surface 9 b of the bumper reinforcement 9 by fastening with a bolt or the like (not shown). In this embodiment, redundancy and detection accuracy are ensured by installing two pressure sensors 3 in this way.

The pressure sensor 3 is connected to both left and right ends of the detection tube member 2 and is configured to detect the pressure in the hollow portion 2a of the detection tube member 2. Specifically, the pressure sensor 3 is a sensor device that detects a change in the pressure of gas, and detects a change in the pressure of air in the hollow portion 2 a of the tube member 2 for detection. As shown in FIG. 1, the pressure sensor 3 is electrically connected to a collision detection ECU (Electronic Control Unit) 6 via a signal line, and outputs a signal proportional to the pressure to the collision detection ECU 5. The collision detection ECU 5 detects a pedestrian collision with the bumper cover 7 based on the pressure detection result by the pressure sensor 3. Further, the collision detection ECU 5 is electrically connected to the pedestrian protection device 10.

As shown in FIG. 4, the pressure sensor 3 includes a sensor main body 30, a sensing unit 31 for pressure detection, a pressure introduction pipe 32, and a connector unit 33. The sensor body 30 is a box-shaped case for accommodating the sensing unit 31.

The sensing unit 31 includes a substrate on which a sensor element for detecting pressure and the like are provided. The sensing unit 31 detects a pressure change in the hollow portion 2 a of the detection tube member 2 through the pressure introduction tube 32. The sensing unit 31 is electrically connected to a connector 34 provided in the connector unit 33, and transmits a pressure signal proportional to the pressure to the collision detection ECU 5 via the connector 34 and the signal line (see FIG. 1). .

The pressure introducing tube 32 is a substantially cylindrical tube that is inserted inside the end portion of the detection tube member 2 and introduces the pressure in the hollow portion 2 a into the sensing unit 31 provided in the sensor body 30. is there. The pressure introduction pipe 32 has a pressure inlet 32 a that communicates with the hollow portion 2 a of the detection tube member 2 and a pressure discharge port 32 b that communicates with the sensor body 30 of the pressure sensor 3. The cross-sectional shape of the pressure introducing tube 32 is similar to the cross-sectional shape of the detection tube member 2 and is circular in this case. The outer diameter of the pressure introducing tube 32 is set larger than the inner diameter of the detection tube member 2.

In the present embodiment, a speed reduction portion 321 is provided in the middle of a pressure propagation path formed inside the pressure introduction pipe 32. The deceleration part 321 reduces the propagation speed of the pressure wave which arises with a collision in the hollow part 2a.

The deceleration portion 321 is configured to include an expanded portion 321a and a bent portion 321b. In the expanded portion 321a, the cross-sectional area of the internal space of the pressure introducing tube 32 is larger on the sensor body 30 side than on the hollow portion 2a side. Specifically, the expanding portion 321a is formed in a tapered shape whose inner wall surface gradually increases in the cross-sectional area of the internal space of the pressure introducing tube 32 along the direction from the hollow portion 2a toward the sensor body 30. .

The bent portion 321b has a shape in which the propagation path of the pressure wave in the internal space of the pressure introducing pipe 32 is bent at a substantially right angle. The bent portion 321b is formed between the expanded portion 321a and the pressure discharge port 32b. In the pressure discharge port 32b, the cross-sectional area of the internal space of the pressure introduction pipe 32 is larger than that of the pressure intake port 32a.

The speed sensor 4 is a sensor device that detects the speed of the vehicle, and is electrically connected to the collision detection ECU 5 via a signal line. The speed sensor 4 transmits a speed signal proportional to the vehicle speed to the collision detection ECU 5.

The collision detection ECU 5 is composed mainly of a CPU and controls the overall operation of the vehicle collision detection apparatus 1, and is electrically connected to each of the pressure sensor 3, the speed sensor 4, and the pedestrian protection apparatus 10. (See FIG. 1). The collision detection ECU 5 receives a pressure signal from the pressure sensor 3, a speed signal from the speed sensor 4, and the like. The collision detection ECU 5 executes a predetermined collision determination process based on the pressure signal from the pressure sensor 3 and the speed signal from the speed sensor 4, and detects a collision of an object such as a pedestrian on the bumper cover 7. Is output to activate the pedestrian protection device 10.

The bumper 6 is for reducing a shock at the time of a vehicle collision, and includes a bumper cover 7, a bumper absorber 8, a bumper reinforcement 9, and the like. The bumper cover 7 is provided so as to cover the components of the bumper 6 and is a resin member such as polypropylene. The bumper cover 7 constitutes the appearance of the bumper 6 and at the same time constitutes a part of the appearance of the entire vehicle.

The bumper absorber 8 is disposed at a position facing the front surface 9a of the bumper reinforcement 9 (that is, the vehicle front side). The bumper absorber 8 is a member responsible for shock absorption in the bumper 6, and is made of, for example, foamed polypropylene. As shown in FIG. 3, a groove 8a for mounting the detection tube member 2 is formed in the rear surface 8b of the bumper absorber 8 along the vehicle width direction. The groove 8a has a rectangular cross-sectional shape and extends in the vehicle width direction.

The length of the groove portion 8a in the vehicle vertical direction is set to be longer than the length of the detection tube member 2 in the vehicle vertical direction (that is, the length of the outer diameter). The vertical length of the groove 8a of this embodiment is set to about 10 mm. Further, the length of the groove portion 8a in the vehicle front-rear direction is set to the same length as the length of the detection tube member 2 in the vehicle front-rear direction (that is, the length of the outer diameter). In addition, the vertical length of the groove part 8a should just be more than the length of the outer diameter of the tube member 2 for a detection, and can be changed suitably.

The bumper reinforcement 9 is a rigid member made of metal such as aluminum which is disposed in the bumper cover 7 and extends in the vehicle width direction. As shown in FIG. It is. The bumper reinforcement 9 has a front surface 9a which is a surface on the vehicle front side and a rear surface 9b which is a surface on the vehicle rear side. As shown in FIGS. 1 and 2, the bumper reinforcement 9 is attached to the front end of a side member 11 that is a pair of metal members extending in the vehicle front-rear direction.

Usually, in a vehicle collision accident, there are many cases where the vehicle collides with a pedestrian or vehicle existing in the traveling direction of the vehicle, that is, in front of the vehicle. For this reason, in this embodiment, the pressure sensor 3 is disposed on the rear surface 9b of the bumper reinforcement 9, and a bumper cover 7 provided with an impact caused by a collision with a pedestrian or vehicle in front of the vehicle is provided in front of the vehicle. The presence of the bumper reinforcement 9 protects the direct transmission to the pressure sensor 3.

Although not shown, the fitting convex portion provided on the rear surface 8b of the bumper absorber 8 is fitted into the fitting concave portion provided on the front surface 9a of the bumper reinforcement 9, so that the bumper rain of the bumper absorber 8 is provided. Assembly to the force 9 is performed.

For example, a pop-up hood is used as the pedestrian protection device 10. The pop-up hood raises the rear end of the engine hood instantly after detecting the collision of the vehicle, increases the clearance between the pedestrian and hard parts such as the engine, and uses that space to impact energy on the pedestrian's head. Absorbs and reduces the impact on the pedestrian's head. Instead of the pop-up hood, a cowl airbag or the like that cushions a pedestrian's impact by deploying the airbag from the engine hood outside the vehicle body to the lower part of the front window may be used.

Next, the operation at the time of collision of the vehicle collision detection apparatus 1 in the present embodiment will be described. When an object such as a pedestrian collides with the front of the vehicle, the bumper cover 7 of the bumper 6 is deformed by an impact caused by the collision with the pedestrian. Subsequently, the bumper absorber 8 is deformed while absorbing the impact, and at the same time, the detection tube member 2 is also deformed. At this time, the pressure in the hollow part 2a of the tube member 2 for detection rises rapidly. That is, a pressure wave is generated in the hollow portion 2a with the collision. This pressure wave propagates from the hollow portion 2 a through the pressure introduction pipe 32 to the sensor body 30 of the pressure sensor 3.

Here, in this embodiment, since the spreading part 321a is provided in the speed reduction part 321, when the pressure wave passes through the spreading part 321a, the propagation speed of the pressure wave decreases. That is, the following continuous equation is established for the fluid flowing through the pipeline, so that the fluid velocity decreases as the sectional area of the pipeline increases.

ρvA = constant (Formula 1)
In Equation 1, ρ is the density of the fluid, v is the velocity of the fluid, and A is the cross-sectional area of the pipe. In this case, it is assumed that the density ρ of air, which is a fluid, is constant, and the propagation velocity v of the pressure wave is reduced by increasing the pipe cross-sectional area A in the spread portion 321a.

Further, in the present embodiment, since the speed reducing portion 321 is provided with the bent portion 321b, the propagation speed of the pressure wave further decreases when passing through the bent portion 321b. This is because the bending portion 321b has a bending loss due to the generation of vortices in the air flow in the pipe. Here, “bending loss” means that the mechanical energy of the fluid is lost due to the presence of a bent portion in the air flow path. Specifically, the amount corresponding mechanical energy loss head h _b in the following equation is lost.

_{_{_{^{h b = ζ b · (v}}}} m 2 / 2g) ··· ( Equation 2)
In Equation 2, ζ _b is a loss factor, v _m is the fluid velocity at the bend, and g is the gravitational acceleration. In the present embodiment, the bent portion 321b which corresponds to the bent portion with the fact that the pressure wave passes, an amount corresponding mechanical energy loss head h _b is lost. Thereby, the propagation speed of the pressure wave on the sensor body 30 side after passing through the bent portion 321b further decreases.

In this embodiment, the pressure discharge port 32b communicating with the sensor body 30 has a larger cross-sectional area of the internal space of the pressure introducing pipe 32 than the pressure intake port 32a communicating with the hollow portion 2a. For this reason, the propagation velocity of the pressure wave is more reliably reduced by the above-described formula 1.

As described above, in the present embodiment, the pressure wave generated in the hollow portion 2a due to the collision is introduced into the sensor body 30 of the pressure sensor 3 after the propagation speed of the pressure wave is reduced by the speed reduction portion 321. The pressure value is detected by the sensing unit 31. The sensing unit 31 outputs a pressure signal proportional to the pressure value to the collision detection ECU 5 via the connector 34 and the signal line.

When the propagation speed of the pressure wave is decreased, the amplitude of the pressure wave detected by the sensing unit 31 can be reduced as shown in FIG. On the other hand, when the propagation speed of the pressure wave is large, the amplitude of the pressure wave detected by the sensing unit 31 is large as shown in the reference example of FIG. Here, the collision detection ECU 5 executes a predetermined collision determination process based on acquiring the pressure detection value from the pressure sensor 3 at a predetermined sampling period. When the amplitude of the pressure wave is large, a negative value may be mixed with the pressure detection value of the pressure sensor 3 (see FIG. 6), and the calculation of the effective mass of the collision object described later may not be performed accurately. Moreover, the pressure detection value output from the pressure sensor 3 may not be accurately acquired by the collision detection ECU 5. Therefore, in the present embodiment, the collision determination processing by the collision detection ECU 5 can be performed accurately by reducing the propagation speed of the pressure wave and reducing the amplitude of the pressure wave.

In the collision determination process by the collision detection ECU 5, for example, the effective mass of the collision object is calculated based on the detection results of the pressure sensor 3 and the speed sensor 4, and when this effective mass is larger than a predetermined threshold, the collision with the pedestrian is detected. It is determined that it has occurred. Furthermore, when the vehicle speed is within a predetermined range (for example, a range of 25 km to 55 km / h), it is determined that a collision with a pedestrian requiring the operation of the pedestrian protection device 10 has occurred.

“Effective mass” refers to the mass calculated from the detected value of the pressure sensor 3 at the time of collision using the relationship between momentum and impulse. When a collision between a vehicle and an object occurs, the value of the detected pressure sensor 3 is different for a collision object having a mass different from that of a pedestrian. For this reason, by setting a threshold value between the effective mass of the human body and the mass of another assumed collision object, it is possible to classify the types of the collision object. The effective mass is calculated by dividing the constant integral value of the pressure value detected by the pressure sensor 3 at a predetermined time by the vehicle speed detected by the speed sensor 4 as shown in the following equation.

M = (∫P (t) dt) / V (Equation 3)
M is an effective mass, P is a value detected by the pressure sensor 3 at a predetermined time, t is a predetermined time (for example, several ms to several tens of ms), and V is a vehicle speed at the time of collision detected by the speed sensor 4. ing. As another method for calculating the effective mass, it is possible to calculate using an equation E = 1/2 · MV ² representing the kinetic energy E of the collided object. In this case, the effective mass is calculated by M = 2 · E / V ² .

When the collision detection ECU 5 determines that a collision has occurred with a pedestrian that requires the operation of the pedestrian protection device 10, the collision detection ECU 5 outputs a control signal for operating the pedestrian protection device 10 to operate the pedestrian protection device 10. As described above, the impact on the pedestrian is reduced.

As described above, the vehicle collision detection device 1 according to the first embodiment includes the detection tube member 2 disposed in the vehicle bumper 6 and having the hollow portion 2a formed therein, and the detection tube member. A pressure sensor 3 for detecting the pressure in the hollow portion 2a of the two, and a collision detection ECU 5 as a collision detection unit for detecting a collision of an object with the bumper 6 based on a pressure detection result by the pressure sensor 3. Yes. The pressure sensor 3 includes a sensor main body 30 provided with a sensing unit 31 for pressure detection, and a pressure introduction pipe 32 for introducing pressure into the sensor main body 30, and the pressure introduction pipe 32 is the detection tube member 2. The pressure inside the hollow portion 2 a is introduced into the sensor body 30 by being inserted inside the end portion. The pressure introducing pipe 32 is provided with a speed reducing portion 321 for reducing the propagation speed of the pressure wave generated in the hollow portion 2a due to the collision.

According to this configuration, the sensing unit 31 detects the propagation speed of the pressure wave generated in the hollow portion 2a due to the collision by the speed reducing unit 321 provided in the pressure introduction pipe 32 of the pressure sensor 3. The pressure wave amplitude can be reduced. Thereby, it can suppress that a negative value is mixed with the pressure detection value from the pressure sensor 3, and the pressure detection value output from the pressure sensor 3 can be correctly acquired by the collision detection ECU 5. Therefore, the collision detection accuracy of the vehicle collision detection apparatus 1 can be improved.

Further, the speed reduction part 321 has an expanded part 321a in which the cross-sectional area of the internal space of the pressure introduction pipe 32 is larger on the sensor body 30 side than on the hollow part 2a side. According to this configuration, the expanded portion 321a causes the cross-sectional area of the internal space of the pressure introduction pipe 32 to be larger on the sensor body 30 side than on the hollow portion 2a side, so that the pressure wave is based on the above-described continuous equation. The propagation speed of can be effectively reduced.

Further, the inner wall surface of the pressure introducing pipe 32 is formed in a tapered shape in which the cross-sectional area of the internal space of the pressure introducing pipe 32 gradually increases along the direction from the hollow portion 2a to the sensor body 30 in the expanded portion 321a.

According to this configuration, the expanding portion 321a is formed in a tapered shape in which the cross-sectional area of the internal space of the pressure introducing tube 32 gradually increases along the direction from the hollow portion 2a toward the sensor body 30. By rapidly increasing the cross-sectional area of the internal space of the tube 32, the flow of the pressure wave can be prevented from being disturbed, and the amplitude of the pressure wave can be effectively reduced.

Further, the speed reduction part 321 has a bent part 321b in which the propagation path of the pressure wave in the internal space of the pressure introduction pipe 32 is bent. According to this configuration, when the pressure wave propagates through the bent portion 321b, a bending loss due to the generation of vortices or the like occurs in the air flow in the pipe, so that the propagation speed of the pressure wave can be reliably reduced. .

Further, the cross-sectional area of the internal space of the pressure introducing pipe 32 is larger in the pressure discharge port 32b communicating with the sensor body 30 than in the pressure intake port 32a communicating with the hollow portion 2a.

According to this configuration, since the cross-sectional area of the internal space of the pressure introduction pipe 32 is larger in the pressure discharge port 32b than in the pressure intake port 32a, the propagation speed of the pressure wave based on the above-described continuous equation. Can be reliably reduced.

Further, the cross-sectional shape of the pressure introducing tube 32 is similar to the cross-sectional shape of the detection tube member 2. According to this configuration, since the cross-sectional shape of the pressure introduction tube 32 is similar to the cross-sectional shape of the detection tube member 2, it is possible to ensure the sealing property of the connection portion between the pressure introduction tube 32 and the detection tube member 2. it can.

Further, the outer diameter of the pressure introducing pipe 32 is set larger than the inner diameter of the detection tube member 2. According to this configuration, since the outer diameter of the pressure introduction tube 32 is set larger than the inner diameter of the detection tube member 2, the hermeticity of the connection portion between the pressure introduction tube 32 and the detection tube member 2 is improved. Can do.

[Second Embodiment]
A second embodiment will be described with reference to FIGS. 7 and 8, the same parts as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different parts are described. In the second embodiment, as shown in FIGS. 7 and 8, the speed reducing portion 322 is configured to have a plurality of protruding portions 322 a on the inner wall surface of the pressure introducing pipe 32.

The protrusions 322a are formed integrally with the pressure introduction pipe 32, and as shown in FIG. 7, a plurality of protrusions 322a are provided at predetermined intervals in the longitudinal direction of the inner wall surface of the pressure introduction pipe 32. In this case, a total of six projecting portions 322 a are provided in each of three on the vehicle upper side and the lower side on the inner wall surface of the pressure introducing pipe 32. Further, as shown in FIG. 8, the protruding portion 322a protrudes radially inward from the inner wall surface of the pressure introducing tube 32 by a predetermined length (for example, several mm).

Further, similarly to the first embodiment, the speed reduction portion 322 has a bent portion 322b. The bent portion 322b has a shape in which the propagation path of the pressure wave in the internal space of the pressure introducing tube 32 is bent at a substantially right angle. The bent portion 322b is formed in the vicinity of the pressure discharge port 32b. Further, in the pressure discharge port 32b, the cross-sectional area of the internal space of the pressure introduction pipe 32 is larger than that of the pressure intake port 32a.

In the vehicle collision detection apparatus 1 according to the second embodiment described above, the speed reduction portion 322 has at least one protrusion 322a that protrudes radially inward from the inner wall surface of the pressure introduction pipe 32 by a predetermined length. is doing.

In the second embodiment, the same effect as that of the first embodiment can be obtained. That is, the speed reduction part 322 has at least one or more protrusions 322a that protrude inward in the radial direction by a predetermined length from the inner wall surface of the pressure introduction pipe 32, so that the pressure wave collides with the protrusions 322a. Thus, the propagation speed of the pressure wave can be reliably reduced, and the amplitude of the pressure wave can be reliably reduced.

[Third Embodiment]
A third embodiment will be described with reference to FIGS. 9 and 10. 9 and 10, the same parts as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different parts are described. In the third embodiment, as shown in FIGS. 9 and 10, the speed reducing portion 323 is provided on the inner wall surface of the pressure introducing pipe 32 with a filter member 323 a that reduces the propagation speed of the pressure wave below a predetermined speed. Have. Further, in the speed reduction portion 323, the frictional resistance of the inner wall surface of the pressure introduction pipe 32 is larger than the other portions.

As shown in FIG. 10, the filter member 323 a is configured to have a breathable mesh filter, and is attached to the inner wall surface of the pressure introduction pipe 32 on the pressure inlet 32 a side. This filter is designed so that the flow velocity of air is a predetermined velocity (for example, 40 m / s) or less. In the third embodiment, when the pressure wave passes through the filter member 323a, the propagation speed of the pressure wave is reduced to a predetermined speed (for example, 40 m / s) or less. In addition, the arrangement | positioning position of the filter member 323a can be changed suitably, for example, may be provided in the inner wall surface by the side of the pressure discharge port 32b of the pressure introduction pipe 32. FIG.

Although not shown, the inner wall surface of the speed reducing portion 323 is formed to have a rougher surface than other portions. Thereby, in the deceleration part 323, the flow of air receives friction loss, and the propagation speed of a pressure wave reduces gradually. In addition, you may make it the frictional resistance of the inner wall surface of the deceleration part 323 become larger than the other part by making the inner wall surface of the deceleration part 323 into an uneven shape.

Further, similarly to the first embodiment, the speed reduction portion 323 has a bent portion 323b. The bent portion 323b has a shape in which the propagation path of the pressure wave in the internal space of the pressure introducing tube 32 is bent at a substantially right angle. The bent portion 323b is formed in the vicinity of the pressure discharge port 32b. Further, in the pressure discharge port 32b, the cross-sectional area of the internal space of the pressure introduction pipe 32 is larger than that of the pressure intake port 32a.

In the vehicle collision detection apparatus 1 according to the third embodiment described above, the speed reduction unit 323 includes the filter member 323a that is provided on the inner wall surface of the pressure introduction pipe and reduces the propagation speed of the pressure wave to a predetermined speed or less. In addition, the frictional resistance of the inner wall surface of the pressure introducing pipe 32 is larger than that of the other portions.

In the vehicle collision detection apparatus 1 of the third embodiment, the same effect as that of the first embodiment can be obtained. That is, the speed reduction part 323 has a filter member 323a provided on the inner wall surface of the pressure introducing pipe to reduce the pressure wave propagation speed to a predetermined speed or less, so that the pressure wave propagation speed is predetermined by the filter member 323a. It can be reliably reduced below the speed. Moreover, since the frictional resistance of the inner wall surface of the pressure introducing pipe 32 is larger than that of the other portions of the speed reducing portion 323, the speed wave propagation speed can be gradually reduced by the speed reducing portion 323. In this way, the amplitude of the pressure wave detected by the sensing unit 31 of the pressure sensor 3 can be reduced more reliably.

[Other Embodiments]
The present disclosure is not limited to the above-described embodiments, and various modifications or expansions can be made without departing from the spirit of the present disclosure. For example, in the above embodiment, the pressure introducing pipe 32 is provided with the bent portions 321b to 323b. However, the present invention is not limited to this, and the bent portions 321b to 323b may not be provided.

In addition, it is assumed that the arrangement position, the number, and the protrusion length of the protrusions 322a in the second embodiment can be changed as appropriate. Further, the protruding portion 322 a may not be integrally formed with the pressure introducing tube 32, and the protruding portion 322 a made of another member may be integrated with the pressure introducing tube 32.

In the above embodiment, the effective mass is calculated based on the pressure detection result, and when the effective mass exceeds the collision determination threshold in the collision determination process, the collision with the pedestrian that requires the operation of the pedestrian protection device 10 is performed. However, the present invention is not limited to this. That is, the pressure detection result may be used as it is. For example, a configuration may be used in which the collision determination is performed by comparing the pressure detection result with the respective collision determination thresholds using a pressure value, a pressure change rate, or the like.

Claims

A detection tube member (2) disposed in a vehicle bumper (6) and having a hollow portion (2a) formed therein, and a pressure sensor (3) for detecting the pressure in the hollow portion of the detection tube member And a collision detection unit (5) for detecting a collision of an object with the bumper based on a pressure detection result by the pressure sensor,
The pressure sensor includes a sensor body (30) provided with a sensing unit (31) for pressure detection, and a pressure introduction pipe (32) for introducing pressure into the sensor body. Inserting the pressure in the hollow part into the sensor body by being inserted inside the end of the tube member for detection,
The vehicle collision detection device, wherein the pressure introduction pipe is provided with a speed reduction portion (321, 322, 323) for reducing a propagation speed of a pressure wave generated in the hollow portion due to a collision.
The said deceleration part (321) has the expansion part (321a) from which the cross-sectional area of the internal space of the said pressure introduction pipe | tube became larger at the said sensor main body side rather than the said hollow part side. Vehicle collision detection device.
The inner wall surface of the pressure introduction pipe is formed in a tapered shape in which the cross-sectional area of the internal space of the pressure introduction pipe gradually increases along the direction from the hollow portion toward the sensor body in the expanded portion. The vehicle collision detection device according to claim 1.
The said deceleration part (322) has at least 1 or more protrusion part (322a) which protruded in the radial direction inner side only predetermined length from the inner wall face of the said pressure introduction pipe | tube. The vehicle collision detection device according to the item.
The vehicular collision detection device according to any one of claims 1 to 4, wherein the deceleration portion (323) has a frictional resistance of an inner wall surface of the pressure introducing pipe larger than that of the other portion.
The said deceleration part (323) has the filter member (323a) which is provided in the inner wall face of the said pressure introduction pipe | tube, and reduces the propagation speed of the said pressure wave below to predetermined speed. The vehicle collision detection device according to the item.
The vehicle according to any one of claims 1 to 6, wherein the speed reducing portion includes a bent portion (321b, 322b, 323b) in which a propagation path of the pressure wave in the internal space of the pressure introducing pipe is bent. Collision detection device.
The cross-sectional area of the internal space of the pressure introduction pipe is larger in the pressure discharge port (32b) communicating with the sensor body than in the pressure intake port (32a) communicating with the hollow portion. The vehicle collision detection device according to claim 7.