JP2008239121A - Vehicle side collision detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle side collision detection device capable of enhancing determination accuracy of side collision and accurately performing collision determination at an earlier stage. <P>SOLUTION: The vehicle side collision detection device is provided with a pressure sensor 3 for detecting pressure change in a door interior space, a pressure corresponding switch 4 for outputting an ON/OFF signal in accordance with opening/closing of an electric contact part mechanically openable/closable according to pressure change in the door interior space, and a side collision determination device 5 for determining whether or not side collision occurred based on the sensor output from the pressure sensor 3 and the ON/OFF signal from the pressure corresponding switch 4. During pressure change in the door interior space, when two collision determination conditions where the sensor output output from the pressure sensor 3 exceeds a collision determination threshold value and where the electric contact part of the pressure corresponding switch 4 is mechanically opened to output an ON signal are achieved, the side collision determination device 5 determines that side collision has occurred. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a side collision detection device for a vehicle that detects an impact caused by a side collision of a vehicle and outputs an ON signal (operation signal) to an occupant protection device such as a side airbag device.

  Some recent vehicles (automobiles) are equipped with side airbag devices and head protection airbag devices to improve the passenger protection function. Based on this, the airbag bag body of the side airbag device and the head protection airbag device is instantaneously deployed (inflated) to protect the trunk side and the head portion of the occupant in the passenger compartment.

  As a collision detection sensor for detecting a side collision event of a vehicle, a pressure sensor that detects a pressure change in the space inside the door of the vehicle at the time of a side collision is used (for example, see Patent Document 1).

In addition to the pressure sensor, an acceleration sensor that detects a change in acceleration associated with the deformation of the door at the time of a side collision is used as a collision detection sensor for detecting a side collision event of a vehicle (for example, Patent Documents). 2).
Japanese Patent No. 2654428 JP 2007-30799 A

  By the way, since a pressure sensor as a collision detection sensor generally uses a semiconductor pressure sensor element such as a piezo element, the sensor output is easily affected by electromagnetic noise or the like. For this reason, in order to prevent the influence of electromagnetic noise etc. and to detect a pressure change with high accuracy, the configuration of the sensor unit becomes complicated and the cost increases.

  In addition, when an acceleration sensor is used as a collision detection sensor, the rigidity of the door is lower than the front side of the vehicle body due to the structure of the vehicle body. For example, in the initial stage of a side collision that collides with a narrow range of the door, the deceleration is small. In addition, since the transmission of impact to the acceleration sensor is delayed, it takes time for the sensor output corresponding to the acceleration to exceed a predetermined collision determination threshold. For this reason, when an acceleration sensor is used, the collision determination may be delayed depending on the collision situation.

  In addition, when both the pressure sensor and the acceleration sensor are installed in the door interior space and the collision judgment is established based on the sensor output from both sensors in order to increase the accuracy of judging the side collision by the sensor output of the collision detection sensor. It is also conceivable to output an ON signal (operation signal) for deploying (inflating) the airbag bag body to an occupant protection device (such as a side airbag device or a head protection airbag device). However, even if the collision is judged early based on the sensor output of the pressure sensor, the output of the ON signal to the occupant protection device is delayed because the collision judgment based on the sensor output of the acceleration sensor is delayed depending on the collision situation as described above. There are things to do.

  In view of the above, an object of the present invention is to provide a vehicle side collision detection apparatus that can increase the accuracy of determination of a side collision and can perform the collision determination earlier and with higher accuracy.

  To achieve the above object, a vehicle side collision detection apparatus according to the present invention is provided in a vehicle interior space, and includes a pressure sensor comprising a semiconductor pressure sensor element for detecting a pressure change in the interior space of the vehicle, A pressure corresponding switch that is provided in the interior space of the door and outputs an ON / OFF signal in response to opening / closing of an electrical contact portion that is mechanically openable / closable according to a pressure change in the interior space of the door, and is output from the pressure sensor. Side collision determination means for determining whether or not a side collision has occurred based on a sensor output and an ON / OFF signal output from the pressure corresponding switch, wherein the side collision determination means includes the door interior space. When the pressure changes, the sensor output output from the pressure sensor exceeds a preset collision judgment threshold, and the electrical contact portion of the pressure corresponding switch is opened from a mechanically closed state. Side collision when two collision determination conditions that the ON signal is outputted is satisfied becomes state is characterized by judging that occurred.

  The pressure-compatible switch includes a coil spring having a predetermined spring constant that applies a biasing force to the electrical contact portion, and when the pressure increase in the door interior space exceeds a predetermined pressure, the electrical contact portion is The coil spring is changed from a closed state to an open state against the spring force of the coil spring, and an ON signal is output to the side collision determination means.

  According to the side collision detection device for a vehicle according to the present invention, as a detection means for detecting a side collision, a pressure sensor composed of a semiconductor pressure sensor element and a mechanical opening and closing according to a pressure change in the door inner space at the time of a side collision. And a pressure corresponding switch that outputs an ON / OFF signal in response to opening / closing of a free electrical contact portion, and the side collision determination means preliminarily outputs a sensor output output from the pressure sensor when the pressure in the door interior changes. Side collision is determined by determining that a side collision has occurred when two collision determination conditions are met that exceed the set collision determination threshold and the electrical contact part of the pressure switch is mechanically opened and an ON signal is output. It is possible to improve the determination accuracy.

  The pressure-compatible switch includes a coil spring having a predetermined spring constant that applies an urging force to the electrical contact portion, and when the pressure increase in the door internal space exceeds a predetermined pressure, the electrical contact portion is a spring of the coil spring. By opening against the force and outputting an ON signal, it is possible to accurately determine the side collision without being affected by electromagnetic noise, etc. with an inexpensive configuration, and depending on the collision situation like an acceleration sensor. The collision determination can be performed in a short time without causing a delay in the collision determination.

  Hereinafter, the present invention will be described based on the illustrated embodiments. FIG. 1 is a schematic diagram showing a configuration of a vehicle side collision detection apparatus (hereinafter referred to as a side collision detection apparatus) according to an embodiment of the present invention.

  As shown in FIG. 1, a side collision detection apparatus 1 according to an embodiment of the present invention includes a semiconductor pressure sensor element provided in a space in an automobile (vehicle) door 2 (the door on the left side of the front seat in FIG. 1). Pressure sensor 3, a pressure corresponding switch 4 that mechanically outputs an ON / OFF signal according to a pressure change in the space in the door 2 at the time of a side collision, and a sensor output (pressure detection signal) output from the pressure sensor 3 And a side collision determination device 5 that determines whether or not a side collision has occurred based on the ON / OFF signal output from the pressure corresponding switch 4.

  The pressure sensor 3 is attached to a reinforcing member 6 installed along the vehicle body front-rear direction (left-right direction in FIG. 1) in a door space formed by the door outer panel 2 a and the door inner panel 2 b of the door 2. As the pressure sensor 3, a piezoelectric element as a semiconductor pressure sensor element or the like can be used.

  As shown in FIG. 2, the pressure corresponding switch 4 is installed on the vehicle interior side (upper side in FIG. 2) of the door inner panel 2b, and includes an electric contact portion 7 having first and second contact portions 7a and 7b. A coil spring 8 having a predetermined spring constant that is urged by a spring force against the first and second contact portions 7a and 7b, and a container 9 in which the electrical contact portion 7 and the coil spring 8 are housed are provided. The container 9 is formed with an air vent hole 9a.

  The first contact portion 7 a of the electric contact portion 7 is fixed to the door inner panel 2 b, and the second contact portion 7 b of the electric contact portion 7 is fixed to a thin plate-like contact holding member 10 attached to one end side of the coil spring 8. Has been. The electrical contact portion 7 is electrically turned off when the first and second contact portions 7a and 7b are in contact with each other, and is electrically connected when the first and second contact portions 7a and 7b are separated from each other. It is configured to be in an ON state. The door inner panel 2b facing the contact holding member 10 has an opening 2c.

  The other end side of the coil spring 8 is fixed to the inner surface of the container 9, and the second contact portion 7 b is connected to the first contact portion by the spring force (biasing force) of the coil spring 8 at normal time (non-side collision). The electrical contact portion 7 is held in the OFF state by being brought into contact with 7a. The spring force (biasing force) of the coil spring 8 is the pressure when the pressure change (pressure increase from atmospheric pressure) between the door outer panel 2a and the door inner panel 2b at the time of a side collision becomes about 5 to 10 kPa. Is set to such a value that the second contact portion 7b is separated (ON) from the first contact portion 7a by being applied to the contact holding member 10.

  FIG. 3A is a diagram showing a collision determination threshold B corresponding to a pressure change (A in FIG. 3A) between the door outer panel 2a and the door inner panel 2b at the time of a side collision with respect to the pressure sensor 3. Yes, when the pressure change (pressure increase) A exceeds the collision determination threshold B at the time t2 after the side collision, the side collision determination device 5 determines that the collision determination condition on the pressure sensor 3 side is satisfied.

  FIG. 3B shows an ON switching level corresponding to the pressure change switch 4 corresponding to the pressure change (A in FIG. 3B) between the door outer panel 2a and the door inner panel 2b at the time of a side collision. FIG. 6 is a diagram showing a value (C set from a spring force (biasing force)), and the second contact portion 7b is first driven by a rise in pressure change (pressure rise) A at time t1 (t1 <t2) after a side collision. When separated from the contact portion 7a and turned on (when the ON switching level C is exceeded), the side collision determination device 5 determines that the collision determination condition on the pressure corresponding switch 4 side is satisfied.

  By the way, the deployment determination of the occupant protection airbag due to the final side collision needs to be determined at an optimal timing for occupant protection. This determination is based on the collision determination calculation based on the signal from the pressure sensor 3. Depending on the result, it should be performed at the optimum timing without harm to the passengers. On the other hand, the pressure corresponding switch 4 needs to work as a safing function, and it is only necessary to be able to determine that a collision has occurred. The purpose is to prevent the pressure sensor 3 from being accidentally fired.

  For this reason, as shown in FIGS. 3A and 3B, the collision determination threshold value (ON switching level) for the pressure corresponding switch 4 is greater than the collision determination threshold value of one of the pressure sensors 3 based on these two relationships. The collision determination by the pressure corresponding switch 4 must be determined earlier than the collision determination by the pressure sensor 3. In other words, the collision determination by the pressure corresponding switch 4 is permission for the airbag deployment, and the collision determination by the pressure sensor 3 is an optimal airbag deployment timing determination for protecting the occupant.

  As shown in FIG. 3 (c), the side collision determination device 5 performs both collision determination based on the side collision determination based on the sensor output from the pressure sensor 3 and the side collision determination based on the ON signal from the pressure corresponding switch 4. When the condition is satisfied (time t2 when it is determined that a side collision has occurred based on the ON signal from the pressure sensor 3), it is determined that a side collision has occurred, and an ON signal (deployment signal) a for the occupant protection device 11 is determined. Is output.

  The collision determination threshold B and the ON switching level C shown in FIGS. 3A and 3B are values set in advance through experiments or the like, and are stored in the storage unit (not shown) of the side collision determination device 5. . In addition, the characteristic of the pressure change in the space between the door outer panel 2a and the door inner panel 2b at the time of the side collision shown in FIGS. 3A and 3B is an example, and changes according to the situation of the side collision.

  Next, the operation of the side collision detection apparatus 1 from the normal time (non-side collision) to the side collision of a vehicle (automobile) including the side collision detection apparatus 1 according to the present embodiment will be described.

  During normal operation (at the time of non-side collision), there is no pressure change between the door outer panel 2a of the door 2 and the door inner panel 2b. Therefore, in the pressure corresponding switch 4, as shown in FIG. 2, the second contact portion 7b and the first contact portion 7a are in contact with each other by the spring force (biasing force) of the spring 8, and the electric contact portion 7 is It is held in the OFF state. The pressure sensor 3 is also in a state where no pressure change is detected.

  Then, at the time of a side collision, as shown in FIG. 4, the door outer panel 2a is crushed (deformed) inward (vehicle compartment side) by the impact of the collision, so that the air between the door outer panel 2a and the door inner panel 2b is compressed. Pressure increases. At this time, the increased pressure (for example, about 5 to 10 kPa) P is applied to the contact holding member 10 through the opening 2c and exceeds the ON switching level C set from the spring force of the coil spring 8 (FIG. 3B). )), The second contact portion 7b is separated from the first contact portion 7a against the spring force of the coil spring 8, and the electrical contact portion 7 is turned on. Then, the side collision determination device 5 determines that a side collision has occurred based on the ON signal from the electrical contact portion 7 of the pressure corresponding switch 4. In addition, the compressed air b which flowed in from the opening part 2c is discharged | emitted out of the container 9 through the air vent hole 9a.

  At the same time, the pressure sensor 3 detects a pressure change (pressure increase) due to air compression between the door outer panel 2a and the door inner panel 2b at the time of a side collision. Based on the sensor output (pressure detection signal), when the pressure change exceeds the collision determination threshold B (see FIG. 3A), it is determined that a side collision has occurred.

  Then, as described above, the side collision determination device 5 is configured such that both the side collision determination based on the sensor output from the pressure sensor 3 and the side collision determination based on the ON signal from the pressure corresponding switch 4 are satisfied. Determines that a side collision has occurred and outputs an ON signal (deployment signal) a for deploying (inflating) the airbag bag body to the occupant protection device (side airbag device, head protection airbag device, etc.) 11 To do.

  As described above, the side collision detection apparatus 1 according to the present embodiment has a pressure sensor 3 including a semiconductor pressure sensor element as a detection unit that detects a side collision, and a machine according to a pressure change in the door 2 at the time of a side collision. A pressure corresponding switch 4 that outputs an ON / OFF signal, and outputs an ON signal a to the occupant protection device 11 when it is determined that both the pressure sensor 3 and the pressure corresponding switch 4 have collided sideways. As a result, it is possible to improve the determination accuracy of the side collision.

  Moreover, the pressure corresponding switch 4 includes a coil spring 8 that applies an urging force to the electrical contact portion 7 (first and second contact portions 7a and 7b), and a pressure increase between the door outer panel 2a and the door inner panel 2b. When the pressure exceeds a predetermined pressure, the electrical contact portion 7 opens against the spring force of the coil spring 8 and outputs an ON signal, so that it is possible to determine the side collision without being affected by electromagnetic noise or the like. In addition, it is possible to perform the collision determination in a short time without causing a delay in the collision determination depending on the collision situation like the acceleration sensor.

  In the above embodiment, the pressure sensor 3 for detecting a side collision and the pressure corresponding switch 4 are provided in the space in the door 2 on the left side of the front seat of the automobile (vehicle). However, the present invention is not limited to this. Without limitation, the pressure sensor 3 and the pressure corresponding switch 4 may be similarly provided in the door inner space on the right side of the front seat and the door inner space on the rear seat side.

Schematic which shows the structure of the side collision detection apparatus for vehicles which concerns on embodiment of this invention. The schematic sectional drawing which shows the structure of the pressure corresponding switch of the side collision detection apparatus for vehicles which concerns on embodiment of this invention. (A) is the figure which showed the collision judgment threshold value corresponding to the pressure change of the space in a door at the time of a side collision with respect to a pressure sensor, (b) is the pressure change of the space in a door at the time of a side collision with respect to a pressure corresponding switch. The figure which showed the ON switching level corresponding to (2), (c) is the figure which showed the ON signal (development signal) output when the side collision judgment apparatus judges that the side collision has occurred. The figure which shows the state of the pressure corresponding | compatible switch at the time of a side collision.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle side collision detection apparatus 2 Door 2a Door outer panel 2b Door inner panel 3 Pressure sensor 4 Pressure corresponding switch 5 Side collision judgment apparatus (side collision judgment means)
DESCRIPTION OF SYMBOLS 6 Reinforcement member 7 Electric contact part 7a 1st contact part 7b 2nd contact part 8 Coil spring 9 Container 10 Contact holding member 11 Crew protection device

Claims (2)

A pressure sensor comprising a semiconductor pressure sensor element that is provided in a door inner space of the vehicle and detects a pressure change in the door inner space;
A pressure-compatible switch that is provided in a vehicle door space and outputs an ON / OFF signal in response to opening and closing of an electrical contact portion that can be mechanically opened and closed according to a pressure change in the door space;
Side collision determination means for determining whether or not a side collision has occurred based on a sensor output output from the pressure sensor and an ON / OFF signal output from the pressure corresponding switch;
The side collision determination means is configured such that the sensor output output from the pressure sensor exceeds a preset collision determination threshold when the pressure in the door interior space changes, and the electrical contact portion of the pressure corresponding switch is mechanically closed. It is determined that a side collision has occurred when two collision determination conditions are established in which the ON signal is output from the state to the open state.
A side collision detection device for a vehicle characterized by the above. The pressure-compatible switch includes a coil spring having a predetermined spring constant that applies a biasing force to the electrical contact portion, and when the pressure increase in the door inner space exceeds a predetermined pressure, the electrical contact portion is the coil. From the closed state to the open state against the spring force of the spring, an ON signal is output to the side collision determination means.
The side collision detection device for a vehicle according to claim 1.

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