JP3062431B2 - Presence determination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupancy determining device for determining whether a seat is occupied or absent when interlocking with an airbag.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 10, for example, as shown in FIG. 10, a sensor sheet 2 having a plurality of pressure-sensitive resistors 1 is arranged on a seat, and a resistance due to a load caused by a seated human body. When the resistance value of the body 1 falls below a certain set value, a determination circuit (not shown) holds the presence signal for a certain period of time (DE 4237072).

[0003]

However, in the case of a conventional occupancy determination device, for example, when this occupancy determination device is arranged in the passenger seat of an automobile and interlocked with the passenger side airbag, it is difficult for infants and infants. When using the auxiliary seat such as a child seat, if the user places the baby backward using the auxiliary seat, the load is applied to the pressure-sensitive resistor 1 and the determination circuit outputs the presence signal. . Therefore, there is a problem that the airbag is unnecessarily deployed at the time of a collision.

The present invention solves such a problem. When an occupancy determination device is provided in a seat to interlock with an airbag, when the deployment of the airbag is unnecessary, the presence of the airbag is absent. It is an object of the present invention to provide a presence determination device that determines that a user is present when the user is present.

[0005]

According to a first aspect of the present invention, in order to achieve the above object, when a human body is seated on an auxiliary seat installed on a main seat having a pressure sensing means, the pressure sensing is performed. Means are also provided below the seat surface either forward or rearward from the center of the main seat seat surface, also serving as position detection means for detecting the positional relationship between the main seat and the auxiliary seat, and an auxiliary seat is provided on the main seat. A recess is provided in a portion of the bottom surface of the auxiliary seat opposite to the upper portion of the pressure-sensitive means when installed rearward, and if the auxiliary seat is installed facing forward based on an output signal of the pressure-sensitive means, the seat is occupied. It is characterized by having a determining means for determining that the auxiliary seat is absent if the auxiliary seat is installed backward.

According to the first aspect of the present invention, only when the auxiliary seat is installed rearward on the main seat, the concave portion of the auxiliary seat is opposed to the upper portion of the position detecting means also serving as the pressure sensing means. If the auxiliary seat is rearward, the weight is transmitted to the pressure-sensitive means even if the human body is seated and is determined to be absent, and if the auxiliary seat is forward, the weight is transmitted to the pressure-sensitive means and determined to be present. When the auxiliary seat is not used, it is determined that a human body is directly seated on the main seat, and it is determined that the human body is absent. Further, since it is not necessary to separately install the pressure sensing means and the position detecting means, the cost can be reduced by reducing the number of parts, and the installation work is facilitated.

According to a second aspect of the present invention, the position detecting means has a magnetic detecting portion disposed below the seat surface either forward or rearward from the center of the seat surface of the main seat, and an auxiliary seat is provided on the main seat. A magnet is provided at a position on the bottom surface of the auxiliary seat opposite to the upper portion of the magnetic detection unit when is disposed rearward.

According to the second aspect, the magnet of the auxiliary seat is opposed to the upper part of the magnetic detection unit only when the auxiliary seat is installed rearward on the main seat, so that the human body sits on the auxiliary seat. Even if the weight is transmitted to the pressure sensing means, if the auxiliary seat is facing backward, it is determined that the user is absent, and if the auxiliary seat is facing forward, it is determined that the user is present. In addition, since the pressure sensing means can be disposed at an optimum position independent of the position detection means, the detection accuracy of the pressure sensing means can be improved.

According to a third aspect of the present invention, the position detecting means has an impedance detecting portion disposed below the seat surface either forward or rearward from the center of the seat surface of the main seat, and an auxiliary seat is provided on the main seat. An impedance variable unit is disposed at a position on the bottom surface of the auxiliary seat opposite to the upper portion of the impedance detection unit when the device is installed backward.

[0010] According to the third aspect of the invention, the impedance variable section of the auxiliary seat is opposed to the upper portion of the impedance detection section only when the auxiliary seat is installed rearward on the main seat. Even if the seat is seated and the weight is transmitted to the pressure sensing means, it is determined that the user is absent if the auxiliary seat is facing backward, and is determined to be present if the auxiliary seat is facing forward. Further, since the position detecting means detects a response of the variable impedance section to the active action of the impedance detecting section, the detection accuracy of the position detecting means can be improved.

In addition, since the pressure sensing means can be arranged at an optimum position independent of the position detecting means, the detection accuracy of the pressure sensing means can be improved.

According to a fourth aspect of the present invention, the position detecting means has a capacitance detecting portion disposed below the seat surface either forward or rearward from the center of the seat surface on the main seat. When the auxiliary seat is installed facing backward, a capacitance variable section is disposed at a position on the bottom surface of the auxiliary seat opposite to the upper portion of the capacitance detection section.

According to the fourth aspect of the present invention, the capacitance variable section of the auxiliary seat is opposed to the upper portion of the capacitance detection section only when the auxiliary seat is installed rearward on the main seat. Even if the body is seated on the auxiliary seat and the weight is transmitted to the pressure sensing means, if the auxiliary seat is facing backward, it is determined that the user is absent, and if the auxiliary seat is facing forward, it is determined that the user is present. Further, since the position detecting means detects a response of the variable capacitance unit to the active action of the capacitance detecting unit, the detection accuracy of the position detecting means can be improved. In addition, since the capacitance variable section can be formed into a thin sheet having a large area with flexibility and can be disposed in a portion closer to the seating surface, the detection accuracy of the position detecting means can be improved. Further, since the pressure sensing means can be disposed at an optimum position independent of the position detection means, the detection accuracy of the pressure sensing means can be improved.

A fifth invention of the present application is the invention according to the first to fourth inventions, wherein the pressure sensing means detects a natural vibration of a human body on the main seat and the auxiliary seat.

According to the fifth aspect of the present invention, since the pressure sensing means detects the natural vibration of the human body on the main seat and the auxiliary seat, for example, even if the luggage is placed on the main seat or the auxiliary seat, it is not present. It is judged and there is no fear of erroneous judgment.

According to a sixth aspect of the present invention, in the fourth aspect, the pressure sensing means has a piezoelectric element for detecting a natural vibration of a human body on the main seat and the auxiliary seat, and the position detecting means includes the piezoelectric element. The electrical shield member is also configured to also serve as a capacitance detection unit.

According to the sixth aspect, the piezoelectric element detects the natural vibration of the human body on the main seat and the auxiliary seat, and the electric shield member of the piezoelectric element sets the positional relationship between the main seat and the auxiliary seat. Also serves as a capacitance detection unit that detects
Since it is not necessary to install the pressure sensing means and the position detection means as separate bodies, the cost can be reduced by reducing the number of parts, and the installation work becomes easy.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a lower perspective view of the auxiliary seat 4 according to the first embodiment of the present invention, and FIG. 2 shows a perspective view of the main seat 7. As shown in FIG. 1, the auxiliary seat 4 is located at the center of the bottom surface 5 (A in FIG. 1).
−A line), a concave portion 6 is provided at a position forward. FIG. 2
The pressure sensing means 8 also serving as a position detecting means is disposed below the seating surface behind the center of the seating surface of the main seat 7 (line BB in FIG. 2). The pressure-sensitive means 8 is composed of a pressure-sensitive member such as a pressure-sensitive resistor, and outputs a signal having a magnitude proportional to an applied load. The pressure-sensitive member is not particularly limited to the pressure-sensitive resistor as described above. Further, although not shown here, there is provided a judging means for judging the presence or absence based on an output signal from the pressure sensing means 8, and the judging means is built in the main seat 7 or a frame of the main seat 7, for example. It is fixed to.

The operation of the above configuration will be described with reference to the accompanying drawings. FIG. 3 is a left side view showing a state in which the auxiliary seat 4 is installed on the main seat 7. FIG. 3A shows the case where the auxiliary seat 4 is installed forward, and FIG. This is the case when it is installed. In the case of FIG. 3A, since the concave portion 6 of the auxiliary seat does not face the upper part of the pressure sensing means 8, the auxiliary seat 4
For example, when a human body 9 such as an infant sits down, the weight is transmitted to the pressure sensing means 8 and the determination means determines that the person is present. As a determination method, for example, if the output signal from the pressure sensing means 8 is equal to or greater than a preset value, it may be determined that the user is present. The set value can be set by an experiment or the like. Next, in the case of FIG. 3B, since the concave portion 6 of the auxiliary seat 4 is opposed to the upper part of the pressure sensing means 8, even if the human body 9 is seated on the auxiliary seat 4, the weight is not transmitted to the pressure sensing means 8. The means determines that it is absent. As described above, it is determined whether the person is present or absent based on the output signal from the pressure sensing means also serving as the position detecting means. still,
When the human body is directly seated on the main seat 7, the weight is
And the determination means determines that the person is present. Further, even if a baggage such as a bag is placed on the main seat 7, the weight is light and the output signal of the pressure sensing means 8 is small, so that it is determined that there is no baggage.

According to the above-described operation, for example, when the presence of a seat is determined and interlocking with the airbag is performed, conventionally, even when the user uses the auxiliary seat backward, it is determined that the user is present and the airbag is not activated in the event of a collision. However, in the present embodiment, when the user uses the auxiliary seat in the rearward direction, the pressure sensing function also serves as a position detecting means for detecting the positional relationship between the main seat and the auxiliary seat. Since the absence is determined based on the output signal of the means, there is an effect that the airbag is not unnecessarily deployed at the time of collision.

Further, since the pressure sensing means also serving as the position detecting means is disposed below the seat surface behind the center of the main seat, and a concave portion is formed at a position forward of the center of the bottom surface of the auxiliary seat. There is an effect that it is possible to provide a practical presence detection device that determines that the user is absent when the user uses the auxiliary seat backward.

In the first embodiment, as shown in FIG. 1, the recess 6 is formed at a position forward of the center of the bottom surface 5 of the auxiliary seat 4 (line AA in FIG. 1), and as shown in FIG. The pressure sensing means 8 which also serves as a position detecting means is provided below the seat surface behind the center of the seat surface of the seat 7 (line BB in FIG. 2). 6 may be formed at a position behind the center of the bottom surface 5 of the auxiliary seat 4, and the pressure sensing means 8 may be provided below the seat surface in front of the center of the seat surface of the main seat 7.

Next, a second embodiment of the present invention will be described with reference to the drawings. 4A and 4B are external views of the case where the auxiliary seat 4 is installed on the main seat 7 as viewed from the lateral direction. FIG. 4A shows the case where the auxiliary seat 4 is installed facing forward, and FIG. Is installed backward. This embodiment is different from the first embodiment in that, as shown in FIG. 4, the position detecting means has a magnetic detection unit 10 disposed below the seat behind the center of the main seat 7. The auxiliary seat 4 has a magnet 11 disposed at a position forward of the center of the bottom surface.

The magnetic detector 10 outputs a signal having a magnitude proportional to the detected magnetism.

The pressure sensing means 8 is the same as that in the first embodiment, and is installed below the center of the main seat 7 below the seating surface. seat,
The position may be optimized so that it can be installed at a position where a load due to a load or the like can be detected, and the position is not limited to the above position.

The operation of the above configuration will be described with reference to the accompanying drawings. 4 (a) and 4 (b), when a human body 9 such as an infant sits on the auxiliary seat 4, the weight is transmitted to the pressure sensing means 8, and the output signal from the pressure sensing means 8 is set in advance in the determination means. It is determined whether the pressure is equal to or greater than the set pressure sensing value. At this time, as shown in FIG. 4A, when the auxiliary seat 4 is directed forward, the magnet 11 provided on the auxiliary seat 4 is separated from the magnetic detection unit 10, so that the magnetic detection unit 10 does not detect magnetism. When the auxiliary seat 4 faces backward as shown in FIG. 4B, the magnet 11 faces the upper part of the magnetic detection unit 10, and the magnetic detection unit 10 detects magnetism. The determination means determines whether the output signal of the magnetic detection unit 10 has a predetermined magnetic set value even when the output signal from the pressure sensitive means 8 is less than a preset pressure sensitive set value, or even if the output signal is equal to or greater than the pressure sensitive set value. In the above case, it is determined that no signal is present, and if the output signal from the pressure sensing means 8 is equal to or greater than the preset pressure sensing value and the output signal of the magnetic detection unit 10 is less than the predetermined magnetic value, the presence is determined. Judge as a seat. These two set values can be set by experiments or the like. As described above, it is determined whether the person is present or absent based on the output signals from the pressure sensing means and the magnetic detection unit serving as the position detecting means. When the main body 7 is directly occupied by the human body, the weight is transmitted to the pressure sensing means 8 but the magnetism is not detected. Further, when a baggage such as a bag is placed on the main seat 7, the output signal of the pressure sensing means 8 is small, so that it is determined that there is no baggage.

According to the above-described operation, according to the present embodiment, the magnet is provided on the auxiliary seat, and the magnetism detecting unit is provided on the main seat. Is detected, and the installation position of the pressure sensing means can be optimized independently of the magnetic detection unit as the position detecting means, so that the detection accuracy of the pressure sensing means can be improved. Therefore, when the user uses the auxiliary seat backward, it is determined that the user is absent, as in the first embodiment, so that the airbag is not unnecessarily deployed at the time of a collision, and the auxiliary seat is not installed. There is an effect that no erroneous determination is made in the presence determination in such a case.

In the second embodiment, the magnetic detector 10
Is disposed below the seating surface behind the center of the seating surface of the main seat 7 and the magnet 11 is provided at a position forward of the center of the bottom surface of the auxiliary seat 4. Detection unit 10
May be provided below the seat surface in front of the center of the seat surface of the main seat 7, and the magnet 11 may be provided at a position behind the center of the bottom surface of the auxiliary seat 4.

Next, a third embodiment of the present invention will be described.
In the second embodiment, the position detecting means has the magnetic detector 10 disposed below the seat behind the center of the seat of the main seat 7, and the auxiliary seat 4 is disposed at a position forward of the center of the bottom. The position detecting means has an impedance detecting unit disposed at the same position as described above, and has an impedance variable unit at the same position as above on the auxiliary seat 4,
Only when the auxiliary seat 4 is installed rearward on the main seat 7, the impedance variable unit of the auxiliary seat 4 may be opposed to the upper part of the impedance detection unit. In this case, the variable impedance section is configured by a circuit having a simple variable side coil, and the impedance detection section is configured by the same detection side coil and an oscillation circuit coupled to the detection side coil to oscillate the impedance change. What is necessary is just to make it the structure which comprises a frequency detection part which detects by the change of a frequency. According to the above configuration, even if the body is seated on the auxiliary seat 4 and the weight is transmitted to the pressure sensing means 8, if the auxiliary seat 4 is facing backward, the auxiliary coil approaches the upper part of the detection side coil. Greatly changes, and the oscillation frequency also changes greatly. When the auxiliary seat 4 faces forward, the variable side coil does not approach the detection side coil, so that the impedance does not change and the oscillation frequency does not change. Therefore, when the output signal from the pressure sensing means 8 is less than the preset pressure sensing set value, or even when the output signal is equal to or greater than the pressure sensing set value, the change of the frequency detected by the frequency detecting unit is preset. If the output signal from the pressure sensing means 8 is equal to or greater than the preset pressure sensing setting and the change in the frequency detected by the frequency detection unit is less than the preset setting value, it is determined that the signal is absent. If it is, it is determined that the person is present. This has the same effect as the second embodiment. When a human body is directly seated on the main seat 7, the weight is transmitted to the pressure sensing means 8, but there is no change in impedance, so that the determination means determines that the seat is present. Further, when a baggage such as a bag is placed on the main seat 7, the output signal of the pressure sensing means 8 is small, so that it is determined that there is no baggage. The set value can be obtained by, for example, an experiment. Further, the configuration for detecting the impedance change is not limited to the above. Further, the impedance detection unit may be provided below the seating surface in front of the center of the seating surface of the main seat 7, and the variable impedance unit may be provided at a position behind the center of the bottom surface of the auxiliary seat 4.

Next, a fourth embodiment of the present invention will be described.
In the second embodiment, the position detecting means is the main seat 7.
Has a capacitance detecting unit disposed at the same position as that of the same embodiment, a capacitance variable unit is disposed at the same position of the auxiliary seat 4 as that of the same embodiment, and the auxiliary seat 4 is directed backward to the main seat 7. The capacitance changing unit of the auxiliary seat 4 may be opposed to the upper part of the capacitance detecting unit only when the unit is installed in the first position. In this case, for example, the capacitance variable unit is configured by a metal plate, and the capacitance detection unit is configured by the same metal plate or a flexible conductive film as described above and an oscillation circuit to oscillate the capacitance change. What is necessary is just to make the structure which detects by the change of frequency. With the above configuration, even if the human body is seated on the auxiliary seat and the weight is transmitted to the pressure sensing means 8,
If the auxiliary seat 4 is facing backward, the above-mentioned metal plates come close to each other, causing a large change in capacitance and a large change in oscillation frequency. When the auxiliary seat 4 faces forward, the metal plates are separated from each other, so that there is no change in capacitance and no change in oscillation frequency.
Therefore, similarly to the above, when the output signal from the pressure sensing means 8 is smaller than the preset pressure sensing set value, or when the output signal is equal to or greater than the pressure sensing set value, the determination means determines the frequency of the frequency detected by the frequency detection unit. If the change is equal to or greater than a preset set value, it is determined that the user is absent, and the output signal from the pressure sensing means 8 is equal to or greater than the preset pressure sensitive setting, and the change in frequency detected by the frequency detector is set in advance. If it is less than the set value, it is determined that the person is present. This has the same effect as the second embodiment. When a human body is directly seated on the main seat, the capacitance changes and the oscillation frequency also changes, but the change is smaller than when the above-mentioned metal plates approach each other. The above-mentioned set value can be determined by, for example, experiments, taking this point into consideration. Further, the configuration for detecting a change in capacitance is not limited to the above. Further, the capacitance detecting unit is disposed below the seat surface in front of the center of the seat surface of the main seat 7, and the capacitance changing unit is connected to the auxiliary seat 4.
May be disposed at a position behind the center of the bottom surface of.

Next, a fifth embodiment of the present invention will be described.
In the second embodiment, the pressure sensing means 8 is constituted by a pressure sensing member such as a pressure sensing resistor, and outputs a signal having a magnitude proportional to the applied load. The pressure means 8 is configured to extract a natural vibration component of the human body using, for example, a piezoelectric element or a capacitance type acceleration detecting element. FIG.
The block diagram is shown in FIG. 16 is a piezoelectric element, 17 and 1
Reference numeral 8 denotes a first filtering unit and a second filtering unit for extracting a natural vibration component of a human body; 19, a position detecting unit including a metal plate capacitance detecting unit described in the second embodiment; It is a determining means. Further, when the auxiliary seat is installed facing backward, a capacitance variable section having a metal plate is provided on the bottom surface of the auxiliary seat opposite to the upper part of the capacitance detection section.

Here, the frequency characteristics of the output signal from the vibration detection unit when the human body is seated on the main seat or the auxiliary seat and when the luggage such as a bag is placed on the main seat are schematically shown. FIG. 6 shows the state shown in FIG. In FIG. 6, P is output, f is frequency, condition A is when an adult sits on a main seat, condition B is when a child sits on an auxiliary seat, and condition C is when luggage is placed. FIG. 6B shows the characteristics when no vibration is applied from the outside to the main seat, for example, when the vehicle is stopped. FIG. 6B shows the characteristics when the vibration is applied to the main seat from the outside, for example, while the vehicle is running. It is a characteristic of the case. The human body generates vibrations due to the heartbeat or body movements caused by breathing, but the luggage does not generate vibrations.
In the case where no vibration is externally applied to the main seat as shown in (a), the characteristic due to the body motion is f1 on the low frequency side.
Appear around. When vibration is externally applied to the main seat as shown in FIG. 6B, the applied vibration is larger than the vibration due to the above-mentioned body movement, but the external vibration is applied to the human body. The natural vibration component of the human body itself appears around f1. In this case, the luggage has a natural vibration characteristic centered on f2 having a higher frequency than f1. In the case of B in FIG. 6B, the natural vibration characteristic of the auxiliary seat slightly appears near f2. Generally, f1 is 10 Hz or less and f2 is 10 Hz or more. Based on such vibration characteristics, the first filtering section 17 is formed of a band-pass filtering circuit having a center frequency of f1, and the second filtering section 18 is formed of a band-pass filtering circuit having a center frequency of f2.

The operation of the above configuration will be described below. FIG. 7 is a flowchart for explaining the determination method in the determination means 20. First filtering section 17 and second filtering section 1
Assuming that the output signals from the respective signals 8 are V1 and V2, if V1 is zero in step 21, it is determined that there is no presence in step 26. If not, the ratio R between V1 and V2 is calculated in step 22. Next, at step 23, R is compared with a predetermined set value Ro. In FIG. 6B, V1 ≧ V2 when the human body is seated on the main seat or the auxiliary seat as in the conditions A and B, and V1 <V2 when the luggage is placed.
Therefore, Ro may be set to, for example, 1. If the human body is sitting on the main seat or the auxiliary seat system, R
≥ Ro and the process proceeds to step 24. If luggage is placed, R <Ro and it is determined in step 26 that the user is absent.
In step 24, if the auxiliary seat is set forward on the main seat, no change in the capacitance is detected because the capacitance variable unit does not face the upper part of the capacitance detection unit as in FIG. If it is determined in step 25 that the seat is present, and if the auxiliary seat is installed facing backward, a large change in the capacitance will occur because the capacitance variable unit is located above the capacitance detection unit as in FIG. Is detected, and it is determined in step 26 that the user is absent. In step 24, when the human body is directly seated on the main seat, the capacitance changes. However, the change is smaller than when the capacitance detecting unit and the variable capacitance unit approach each other. Is determined. Although Ro is set to 1 in the above description, it can be further optimized and set by experiments.

According to the above operation, the pressure sensing means is constituted by a pressure sensing member such as a pressure sensing resistor as in the second embodiment, and outputs a signal having a magnitude proportional to the applied load. Then, for example, when heavy luggage is placed on the main seat, a large signal is output from the pressure sensing means, and there is a risk that it is determined that there is a seat even though luggage is placed on the main seat, but according to this embodiment Since the presence of a person is determined by detecting the natural vibration characteristics of the human body as shown in FIG. 6, there is an effect that there is no possibility of erroneous determination.

Next, a sixth embodiment of the present invention will be described.
Although the piezoelectric element is used as the pressure sensing means 8 in the fifth embodiment, the piezoelectric material constituting the piezoelectric element has a high impedance, and it is necessary to electrically shield the piezoelectric element during normal use. As shown in FIG. 8, the pressure sensing means 8 is composed of a piezoelectric element 27 and an electric shield member 28 enclosing the piezoelectric element 27, and the shield member 28 also serves as a capacitance detecting unit as the position detecting means 19. You may. A shield line 29 for signal derivation is connected to the pressure sensing means 8. As shown in FIG. 9, the pressure sensing means 8 is provided below the seat surface behind the center of the main seat 7. Reference numeral 30 denotes a capacitance changing unit. According to the above configuration, since the shield member 28 of the pressure sensing means 8 also serves as the capacitance detection unit of the position detection means, the same effect as in the third embodiment can be obtained, and the installation property can be further improved. effective. still,
In the above configuration, the piezoelectric element 27 and its shield member 28
May be provided below the seat surface in front of the center of the seat surface of the main seat 7, and the capacitance variable unit 30 may be provided at a position behind the center of the bottom surface of the auxiliary seat 4.

In the above embodiment, only one pressure sensing means is used. However, a plurality of pressure sensing means may be used. The load due to the weight when sitting on the seat can be detected with higher accuracy.

In the first embodiment, the pressure sensing means is disposed below the seat surface behind the center of the main seat, and a recess is formed at a position forward of the center of the bottom surface of the auxiliary seat. Alternatively, the pressure sensing means may be arranged below both the front and rear seats from the center of the main seat.

According to this configuration, if the human body is directly seated on the main seat, a load is applied to both pressure-sensitive means, and the auxiliary seat is installed on the main seat facing forward and the human body is seated on the auxiliary seat. For example, since the concave portion of the auxiliary seat is opposed to the upper part of the front pressure sensing means, the load is applied only to the rear pressure sensing means, the auxiliary seat is installed backward on the main seat, and the human body sits on the auxiliary seat. If there is, the recess is opposed to the upper part of the pressure sensing means on the rear side, so the load is applied only to the pressure sensing means on the front side, if there is nothing on the main seat or if only luggage and auxiliary seats are placed No load is applied to both pressure-sensitive means. Based on these, the judgment means "the human body is directly sitting on the main seat", "the auxiliary seat is installed on the main seat facing forward and the human body is seated", "the auxiliary seat is facing backward on the main seat And the human body is seated on the floor, "and a more detailed determination of the seated state can be made. Similarly, in the second embodiment, the magnetism detection unit as the position detection means is provided below the seating surface behind the center of the main seating surface, and a magnet is provided at a position forward from the center of the bottom surface of the auxiliary seat. However, the magnetic detection unit may be disposed below the seating surface on both the front and rear sides from the center of the seating surface of the main seat, and if a human body sits directly on the main seat, a load is applied to the pressure sensing means, When the auxiliary seat is installed on the front and the human body is sitting on the auxiliary seat, a load is applied to the pressure-sensitive means and the magnet of the auxiliary seat is opposed to the upper part of the front magnetic detection unit, so the front magnetic field Only the detector detects magnetism,
If the auxiliary seat is installed rearward on the main seat and the human body is seated on the auxiliary seat, a load is applied to the pressure-sensitive means and the magnet of the auxiliary seat faces the upper part of the magnetic detection unit on the rear side, so the rear side Only the magnetism detecting unit detects the magnetism, and when there is nothing on the main seat or when only luggage and auxiliary seats are placed, no load is applied to the pressure sensing means. Based on these, the determination means "the human body is sitting directly on the main seat",
It is possible to judge that "the auxiliary seat is installed facing forward and the human body is seated on the main seat", and "the auxiliary seat is installed backward and the human body is seated on the main seat", and more detailed seating is possible. The state can be determined. Although the above configuration detects magnetism, it may be configured to detect impedance or capacitance.

[0039]

As described above, according to the presence detecting device of the present invention, the following effects can be obtained. (1) In the case where the presence of a seat is determined and interlocking with an automobile airbag is performed, it is conventionally determined that the user is present even when the user uses the auxiliary seat backward, and the airbag is unnecessarily deployed in the event of a collision. However, according to the present invention, when the user uses the auxiliary seat in the rearward direction, when the user is absent based on the output signals of the position detecting means for detecting the positions of the main seat and the auxiliary seat and the pressure sensing means, Since the determination is made, the airbag is not unnecessarily deployed at the time of the collision. (2) A pressure sensing means also serving as a position detection means is disposed below the seat surface either forward or rearward from the center of the main seat seat surface, and the pressure sensing means is provided when an auxiliary seat is installed rearward on the main seat. With a simple configuration in which a concave portion is formed on the bottom surface of the auxiliary seat opposite to the upper portion, cost reduction can be achieved by reducing the number of parts, installation work becomes easy, and the user uses the auxiliary seat backward. It is possible to provide a practical presence detection device that is sometimes determined to be absent. (3) The main seat is provided with a magnet, an impedance variable unit and a variable capacitance unit, and the main seat is provided with a magnetic detecting unit, an impedance detecting unit and a variable capacitance unit in correspondence with the above. When the auxiliary seat is installed on the seat, the direction of the auxiliary seat is detected, so that the same effect as the above (2) is obtained. Furthermore, since the pressure sensing means can be arranged at an optimum position independent of the position detection means, and the detection accuracy of the pressure sensing means can be increased, the erroneous determination of the presence determination when the auxiliary seat is not installed is also possible. There is no. (4) Since the presence of a person is determined by detecting the natural vibration characteristic of the human body, there is no risk of erroneous determination even if heavy luggage is placed on the main seat. (5) Since the natural vibration characteristic of the human body is detected by the piezoelectric element as the pressure sensing means, and the shield member of the piezoelectric element also serves as the capacitance detecting section of the position detecting means, the same effect as in the above (4) is obtained. In addition, the cost can be reduced by reducing the number of parts, and the installation work is facilitated.

[Brief description of the drawings]

FIG. 1 is a lower perspective view of an auxiliary seat according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a main seat in the embodiment.

3A is a left side view showing a state in which an auxiliary seat is installed on a main seat in a forward direction, and FIG. 3B is a left side view showing an auxiliary seat installed on a main seat in a first embodiment of the present invention; The left view which shows the state which performed.

4A is a left side view showing a state in which an auxiliary seat is installed on a main seat in a forward direction, and FIG. 4B is a left side view showing an auxiliary seat installed on a main seat in a second embodiment of the present invention; The left view which shows the state which performed.

FIG. 5 is a block diagram showing a signal flow to a determination unit according to a fifth embodiment of the present invention.

FIG. 6 is a frequency characteristic diagram showing an example of an output signal from a vibration detection unit in the embodiment.

FIG. 7 is a flowchart of a determination method by a determination unit in the embodiment.

FIG. 8 is a perspective view of a pressure sensing unit according to a sixth embodiment of the present invention.

9A is a left side view showing a state in which an auxiliary seat is installed on a main seat in a forward direction, and FIG. 9B is a left side view showing an auxiliary seat installed on a main seat in a sixth embodiment of the present invention. The left view which shows the state which performed.

FIG. 10 is a plan view of a pressure sensing means in a conventional presence detection device.

[Explanation of symbols]

 Reference Signs List 4 auxiliary seat 5 bottom seating surface 6 concave portion 7 main seat 8 pressure-sensitive means 9 human body 10 magnetic detection unit 11 magnet

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yasumasa Ueda 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Maki Morita 1-4-1 Chuo, Wako-shi, Saitama Stock (56) References JP-A-7-165011 (JP, A) JP-A-7-237484 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60N 2 / 44 B60N 5/00

Claims (6)

(57) [Claims] 1. A position detecting means for detecting a positional relationship between a main seat and an auxiliary seat when a human body is seated on an auxiliary seat provided on a main seat having a pressure sensing means; based on the output signal of the pressure means, the auxiliary seat is determined that presence if it is positively installed, the auxiliary seat has an absence and determination means if installed backwards, pressure sensitive means Is also used as the position detecting means.
Located below the seat either forward or backward from the center of the seat
And the auxiliary seat is installed rearward on the main seat.
Part of the bottom surface of the auxiliary seat facing the upper part of the pressure-sensitive means
A presence determination device provided with a concave portion at a position . 2. A position detecting means for detecting a positional relationship between the main seat and the auxiliary seat when a human body is seated on an auxiliary seat provided on the main seat having pressure sensing means, based on the output signal of the pressure means, the auxiliary seat is determined that presence if it is positively installed, the auxiliary seat has an absence and determination means if installed backwards, the position detection The means is located at the center of the seat surface of the main seat.
Magnetic detection located under the seat either forward or rear
Part, the auxiliary seat is arranged rearward on the main seat
The bottom of the auxiliary seat facing the upper part of the magnetic detection unit when
Presence determination device in which magnets are arranged on the surface. 3. A position detecting means for detecting a positional relationship between the main seat and the auxiliary seat when a human body is seated on an auxiliary seat provided on the main seat having pressure sensing means, based on the output signal of the pressure means, the auxiliary seat is determined that presence if it is positively installed, the auxiliary seat has an absence and determination means if installed backwards, the position detection The means is located at the center of the seat surface of the main seat.
Impedance located under the seat either forward or rearward
A dance detection section, and the auxiliary seat is located above the main seat.
When installed in the orientation,
Variable impedance part on the bottom of the auxiliary seat
Presence determining device but disposed. 4. A case where the human body installed auxiliary seat on the main seat having a pressure sensitive means is seated, position detecting means for detecting a positional relationship between the main seat and the auxiliary seat, the sense based on the output signal of the pressure means, the auxiliary seat is determined that presence if it is positively installed, the auxiliary seat has an absence and determination means if installed backwards, the position detection The means is located at the center of the seat surface of the main seat.
Capacitance placed under either the front or rear seat
Having a detection unit, the auxiliary seat on the main seat facing backward
When it is installed, the supplementary portion facing the upper part of the capacitance detecting section
A presence determination device in which a capacitance variable unit is provided at a position on a bottom surface of an auxiliary seat . Wherein the pressure sensitive means, any one of claims 1 to 4 for detecting the natural vibration of the human body on the main seat and on the auxiliary seat 1
Item presence determination device. 6. The pressure-sensitive means has a piezoelectric element for detecting a natural vibration of a human body on the main seat and the auxiliary seat, and the position detecting means comprises an electric shield member including the piezoelectric element and having a capacitance. The presence determination device according to claim 4 , wherein the presence determination device is configured to also serve as a detection unit.