JP4225217B2 - Load sensor and occupant protection system - Google Patents

Description

  The present invention relates to a load sensor that detects a load state of a vehicle seat and an occupant protection system that drives an occupant protection device in response to an occupant state determined from the load state of the seat.

  The occupant protection system includes a load sensor, an occupant detection ECU (electronic control unit), and an airbag ECU. The load sensor is disposed on the seat. The occupant detection ECU determines the occupant state of the seat from the load data of the load sensor. Specifically, it is determined whether the sheet stack is an adult, a child, or a child seat. The airbag ECU determines whether or not to deploy the airbag body based on the determination result of the occupant detection ECU. Specifically, when there is no occupant on the seat, when the occupant is a child, or when a child seat is attached to the seat, the bag body is set in the unprohibited state. On the other hand, if the occupant is an adult, the bag body is allowed to be deployed.

As an example of a load sensor used in an occupant protection system, Patent Document 1 introduces a bladder type load sensor. The load sensor includes a bag body filled with fluid. The bag is disposed under the cushion of the seat. According to this load sensor, the load state of the seat can be detected by measuring the pressure in the bag. Patent Document 2 introduces a mat type load sensor. This load sensor includes a film mat and a pressure-sensitive sensor cell. Many sensor cells are dispersedly arranged on the entire surface of the film mat. The film mat is interposed between the skin of the seat and the cushion. The film mat is arranged over the entire sheet surface. However, the load sensors disclosed in Patent Documents 1 and 2 are both expensive. For this reason, the manufacturing cost of the load sensor and thus the occupant protection system increases.
JP-A-11-148855 JP 2000-296757 A JP 2001-133340 A

  Therefore, Patent Document 3 introduces a load sensor having a membrane switch-like sensor cell. The load sensor described in this document is less expensive than the load sensors described in Patent Documents 1 and 2 above.

  However, the load sensor described in this document is for a vacant seat detection system. That is, it is used to issue an alarm to a passenger who is not wearing a seat belt. The load sensor described in this document can output only on / off information. For this reason, the same ON signal is output regardless of whether the load of sheets is an adult, a child, or a child seat. Therefore, it is impossible to discriminate between adults, children and child seats. In particular, discrimination between an adult and a child seat, in other words, discrimination between an adult and an infant, is important in setting the driving conditions for the occupant protection device.

  The load sensor and occupant protection system of the present invention have been completed in view of the above problems. Accordingly, an object of the present invention is to provide a load sensor and an occupant protection system that can distinguish between an adult and a child seat at low cost.

  (1) In order to solve the above-described problem, the load sensor of the present invention is a load sensor that detects a load state of a vehicle seat by a sensor cell arranged on the seat, and the load distribution when the child seat is mounted on the seat. The center of the detection area is set in at least one area selected from an area having a large difference between the load distribution at the time of boarding an adult and at least one of the sensor cells is arranged in the detection area. .

  That is, the load sensor of the present invention pays attention to the difference between the load distribution when the child seat is mounted and the load distribution when riding an adult. And the detection area | region for sensor cell arrangement | positioning is set to the area | region with a large difference.

  The load sensor of the present invention has been completed as a result of analysis and consideration by the inventor described below. First, the analysis result about the load distribution of the seat on which the child seat is mounted will be described. FIG. 1 shows a side view of a seat on which a child seat is mounted. The child seat 101 is fixed to the seat 100 by a seat belt (not shown). By the way, on the back surface of the child seat 101, ribs are arranged to ensure the stability of the child seat 101 with respect to the seat 100 when mounted. Therefore, when the child seat 101 is mounted, the portion where the rib is disposed is pressed more strongly against the seat 101 than the portion where the rib is not disposed. That is, the shape of the rib is reflected in the load distribution (pressure distribution) of the seat.

  FIG. 2A shows a schematic diagram of a child seat having ribs extending in the front-rear direction, and FIG. 2B shows a pressure distribution of the seat on which the child seat is mounted. The direction is defined with reference to the direction from the rear to the front of the vehicle. The grid (b) is obtained by dividing the rear of the seat 100 into 20 parts in the front-rear direction and 25 parts in the left-right direction (vehicle width direction). Hatching indicates the degree of pressure in each grid. A grid with hatching has a higher pressure than a grid without hatching. Further, the closer the hatching interval, the higher the pressure. (B) was measured with the above-mentioned mat type load sensor.

  As shown to (a), from the back surface of the child seat 101, the rib 102 extended in the front-back direction is protrudingly provided. A total of two ribs 102 are arranged along both edges of the child seat in the vehicle width direction. As shown in (b), the portion of the sheet 100 where the rib 102 is pressed is higher than the portion where the rib 102 is not pressed. For this reason, the hatching pattern corresponding to the rib 102 arrangement site is drawn.

  FIG. 3A shows a schematic view of a child seat having ribs extending in the left-right direction, and FIG. 3B shows a pressure distribution of the seat on which the child seat is mounted. In addition, about the site | part corresponding to FIG. 2, it shows with the same code | symbol. Further, the expression method and measurement method of (b) are the same as in FIG. 2 (b).

  As shown to (a), from the back surface of the child seat 101, the rib 102 extended in the left-right direction is protrudingly provided. The rib 102 crosses right and left substantially in the center in the front-rear direction of the child seat. As shown in (b), the portion of the sheet 100 where the rib 102 is pressed is higher than the portion where the rib 102 is not pressed. For this reason, the hatching pattern corresponding to the rib 102 arrangement site is drawn.

  FIG. 4A shows a schematic diagram of a child seat having U-shaped ribs, and FIG. 4B shows a pressure distribution of the seat on which the child seat is mounted. In addition, about the site | part corresponding to FIG. 2, it shows with the same code | symbol. Further, the expression method and measurement method of (b) are the same as in FIG. 2 (b).

  As shown to (a), from the back surface of the child seat 101, the U-shaped rib 102 opened ahead is protrudingly provided. As shown in (b), the portion of the sheet 100 where the rib 102 is pressed is higher than the portion where the rib 102 is not pressed. For this reason, the hatching pattern corresponding to the rib 102 arrangement site is drawn.

  Next, an analysis result of the load distribution of the seat on which the adult has boarded will be described. FIG. 5 shows a side view of a seat on which an adult is boarded. In addition, about the site | part corresponding to FIG. 1, it shows with the same code | symbol. As shown in the figure, when the adult 103 sits on the seat 100, the buttocks mainly press the seat 100.

  FIG. 6A shows a schematic diagram of an adult pelvis, and FIG. 6B shows a pressure distribution of a seat on which an adult is normally seated. The expression method and measurement method of (b) are the same as in FIG. 2 (b).

  As shown in (b), the sheet 100 has a pair of high-pressure areas, one pair at the front left and right and one at the rear center. These high pressure regions are considered to correspond to the shape of the pelvis. That is, as shown to (a), the pelvis 104 is provided with a pair of seat bones 104a and 104b and the pubic bone 104c. The apex of the ischial bone 104a, the apex of the ischial bone 104b, and the apex of the pubic bone 104c are arranged in a triangular shape. The parts containing the top of the ischia 104a, the top of the ischia 104b, and the top of the pubic bone 104c in the buttocks press the sheet 100 particularly strongly. Therefore, as shown in (b), a dense hatching pattern is drawn on the grid corresponding to the top of the sciatica 104a, the top of the sciatica 104b, and the top of the pubic bone 104c. On the other hand, although not illustrated, the pressure distribution of the seat when the adult puts out the buttocks about 100 mm forward and sits on the seat corresponds to a distribution obtained by shifting the pressure distribution of (b) by 100 mm forward.

  As described above, the pressure distribution of the seat on which the child seat shown in FIGS. 2B to 4B is mounted is clearly different from the pressure distribution of the seat on which the adult is seated in FIG. 6B. In addition, when analyzed in units of grids, there is a grid in which the difference in pressure value is large when a child seat is mounted and when an adult is boarded (for example, no hatching when a child seat is mounted and dense hatching when an adult is boarding). Therefore, if the sensor cells are arranged intensively so as to cover the difference in pressure value, that is, the grid having a large differential pressure, it is not necessary to dare to arrange the sensor cells on the entire surface of the seat as in the case of the load sensor of the above-mentioned mat type. . In view of this point, the present inventor has calculated a difference, that is, a differential pressure distribution, between the pressure distribution of the seat when the child seat is mounted and the pressure distribution of the seat when riding an adult. FIG. 7 shows the differential pressure distribution. The expression method and measurement method in the figure are the same as in FIG.

  The load sensor of the present invention has been completed as a result of the above-described analysis and consideration by the present inventors. The load sensor of the present invention is selected from a region where the differential pressure is large (for example, a hatched region in FIG. 7), that is, a region where the difference between the load distribution when the child seat is mounted and the load distribution when riding an adult is large. The center of the detection area for sensor cell placement is set in at least one area. For this reason, it is not necessary to arrange sensor cells over the entire sheet surface. Therefore, the number of sensor cells arranged can be reduced. That is, the manufacturing cost of the load sensor can be reduced.

  In addition, the sensor cell is arranged in an area most effective for determining the occupant state of the seat. For this reason, although there are few sensor cell arrangement | positioning numbers, an adult and a child seat can be discriminate | determined reliably.

  (2) Preferably, in the configuration of the above (1), the seat includes, as the detection region, a front left detection region that is forward of the hip point design point of the seat and symmetrical with respect to the seat vehicle width direction. It is better to have a configuration in which a right front detection area is set.

  Here, the “hip point” refers to a point corresponding to the center of rotation of the torso and thigh of a three-dimensional human body model (3DM-JM50) for measuring the dimensions of an automobile room in JIS (Japanese Industrial Standards) D4607-1977. . The “hip point design point” means a point where the hip point is suspended and projected on the upper surface of the seat.

  As shown in FIG. 7, the region where the difference between the load distribution when the child seat is mounted and the load distribution when riding an adult is large appears symmetrically on the left and right front of the seat. In this configuration, the centers of the detection areas are arranged in these areas. That is, the left front detection area and the right front detection area are set. According to this configuration, it is possible to reliably discriminate between an adult and a child seat despite the small number of sensor cells. In addition, the manufacturing cost of the load sensor can be further reduced because the number of sensor cells arranged is small.

  (3) Preferably, in the configuration of (2) above, the length of a perpendicular drawn from the hip point design point with respect to a straight line connecting the center of the left front detection region and the center of the right front detection region is The distance from the intersection of the perpendicular and the straight line to each of the centers is preferably set to 65 mm.

  Here, the length of the vertical line is set to 100 mm, not only when an adult is seated normally, but also when an adult sits forward with the buttocks about 100 mm in front and sits down, the adult and child seat are reliably discriminated It is to do.

  That is, this configuration is a portion corresponding to the top portion of the sitting bone 104a and the top portion of the sitting bone 104b when the adult is normally seated as shown in FIG. 6 (a), and the top portion of the sitting bone 104a when the adult is sitting on the front seat. The center of the left front detection region and the center of the right front detection region are set so that both the portion corresponding to the top of the seat bone 104b can be detected. That is, focusing on the size and shape of the pelvis, the left front detection area and the right front detection area are positioned. According to this configuration, the left front detection region and the right front detection region can be positioned based on the hip point design point without depending on the size and shape of the seat. For this reason, it is easy to share a load sensor between a plurality of sheets having different specifications.

  (4) Preferably, in the configuration of (3), the left front detection region and the right front detection region are each in a rectangle having a left-right side length of 100 mm and a front-rear direction side length of 200 mm. It is better to have a configuration that presents an oval shape that touches.

  That is, in this configuration, the range of the left front detection area and the right front detection area positioned in the above (3) is an ellipse inscribed in a rectangle having a predetermined shape. According to this configuration, even if the hip point of the occupant and the hip point design point of the seat are misaligned, it is possible to reliably discriminate between an adult and a child seat.

  Here, the length of the rectangular left and right sides was set to 100 mm and the length of the front and rear sides was set to 200 mm, not only when the adult was seated normally, but also when the adult raised the buttocks forward about 100 mm. This is to ensure that an adult and a child seat are discriminated even when sitting and sitting. Note that the “center” of the detection region in the case where the detection region is an ellipse inscribed in a rectangle as in the present configuration refers to the intersection of the diagonal lines of the rectangle.

  (5) Preferably, in the configuration of (2), a plurality of sensor cells are arranged in each of the left front detection region and the right front detection region. According to this configuration, even if the hip point of the occupant and the hip point design point of the seat are misaligned, it is possible to reliably discriminate between an adult and a child seat.

  (6) Preferably, in the configuration of (2) above, the sensor cell should have a configuration in which the output changes according to the load. According to this configuration, it is possible to determine not only an adult and a child seat but also an adult and a child relatively easily.

  (7) Preferably, in the configuration of (2) above, the sensor cell has a membrane switch shape capable of outputting on / off information, and the sensor cell disposed in the left front detection region includes a left front It is preferable that a resistor is connected in parallel, and a right front resistor is connected in parallel to the sensor cell arranged in the right front detection region. According to this configuration, the manufacturing cost of the sensor cell can be reduced as compared with the above (6).

  (8) Preferably, in the configuration of (7), the resistance value of the left front resistor and the resistance value of the right front resistor are preferably different. According to this configuration, it is possible to identify which one of the sensor cells in the left front detection area and the sensor cell in the right front detection area is on (or whether both of the two detection areas are on).

  (9) Preferably, in the configuration of (7) above, the sensor cell and the left front resistor connected in parallel in the left front detection region, and the sensor cell and the right front in the right front detection region connected in parallel The resistor is preferably connected in parallel.

  That is, in this configuration, the left front detection area and the right front detection area are connected in parallel. According to this configuration, when the sensor cell of at least one of the detection regions (at least one sensor cell of the detection region) is turned on, the potential upstream of the sensor cell changes.

  (10) Preferably, in the configuration of (7), the sensor cell and the left front resistor connected in parallel in the left front detection region, and the sensor cell and the right front in the right front detection region connected in parallel The resistor is preferably connected in series.

  That is, in this configuration, the left front detection area and the right front detection area are connected in series. According to this configuration, when the sensor cell of at least one of the detection regions (at least one sensor cell of the detection region) is turned on, the potential upstream of the sensor cell changes.

  (11) Further, the passenger protection system of the present invention is based on the load sensor according to (7) above and the on / off of the left front detection area and the right front detection area based on the output and resistance value of the load sensor. An occupant detection ECU that determines an occupant state of the seat, and an occupant protection ECU that drives an occupant protection device based on a determination result of the occupant detection ECU, wherein the occupant protection ECU includes: The occupant protection device is driven when both the sensor cell in the left front detection area and the sensor cell in the right front detection area are on.

  That is, the occupant protection system of the present invention determines that an adult is on the seat and drives the occupant protection device when both the left front detection area sensor cell and the right front detection area sensor cell are on. is there. The occupant protection system of the present invention can reliably discriminate between an adult and a child seat despite having a load sensor with a small number of sensor cells. In addition, the manufacturing cost is low because the number of sensor cells is small. Also, the manufacturing cost is low in that the sensor cell has a membrane switch shape.

  (12) Preferably, in the configuration of (11), the vehicle further includes a belt tension sensor that detects tension data of a seat belt corresponding to the seat, and the occupant protection ECU includes the sensor cell in the left front detection region, It is preferable that the occupant protection device is driven when both of the sensor cells in the right front detection area are on and the tension data of the belt tension sensor is less than a predetermined threshold value.

  As described above, the child seat is fixed to the seat by the seat belt. For this reason, when the child seat is mounted on the seat, the tension data of the belt tension sensor becomes larger than when the adult gets on the seat. Focusing on this point, this configuration uses the tension data of the belt tension sensor to distinguish between adults and child seats. That is, in this configuration, when both the sensor cell in the left front detection area and the sensor cell in the right front detection area are on, and the tension data of the belt tension sensor is less than a predetermined threshold, an adult gets on the seat. And the occupant protection device is driven. According to this structure, the discrimination | determination precision between an adult and a child seat becomes high.

  (13) Further, the passenger protection system of the present invention is based on the load sensor described in (7) above and the on / off of the left front detection region and the right front detection region based on the output and resistance value of the load sensor. An occupant protection ECU that determines an occupant state of the seat and drives an occupant protection device based on the determination result, wherein the occupant protection ECU is configured to detect the sensor cell in the left front detection region. The occupant protection device is driven when both of the sensor cells in the right front detection region are on.

  The occupant protection system of the present invention can reliably discriminate between an adult and a child seat despite having a load sensor with a small number of sensor cells. In addition, the manufacturing cost is low because the number of sensor cells is small. Also, the manufacturing cost is low in that the sensor cell has a membrane switch shape. Further, the occupant protection system of the present invention requires fewer parts compared to the occupant protection system of (11) above, because the occupant detection ECU is not arranged.

  (14) Preferably, in the configuration of the above (13), a belt tension sensor that detects tension data of a seat belt corresponding to the seat is further provided, and the occupant protection ECU includes the sensor cell in the left front detection region, It is preferable that the occupant protection device is driven when both of the sensor cells in the right front detection area are on and the tension data of the belt tension sensor is less than a predetermined threshold value. According to this configuration, as described in (12) above, the discrimination accuracy between an adult and a child seat increases.

  (15) Preferably, in the configuration of (1) above, the seat has a back detection region, a left front detection region, and a right as the detection region, with each vertex of an inverted triangle spreading toward the front of the seat as a center. It is better to have a configuration in which a front detection area is set.

  As shown in FIG. 7, the region where the difference between the load distribution when the child seat is mounted and the load distribution when riding an adult is large appears symmetrically on the left and right front of the seat. In addition, an area with a large load distribution difference appears in the approximate center of the rear of the seat, though not as much as the area on the left and right front. In this configuration, the centers of the detection areas are arranged in these areas. That is, the rear detection area, the left front detection area, and the right front detection area are set. According to this configuration, it is possible to reliably discriminate between an adult and a child seat despite the small number of sensor cells. In addition, the manufacturing cost of the load sensor can be reduced because the number of sensor cells arranged is small. Further, as compared with the configurations (2) to (14), the greater the detection area, the higher the discrimination accuracy between an adult and a child seat. In addition, the load on the rear detection region is likely to appear when the occupant gets on the seat. For this reason, the determination accuracy of the vacant seat determination for determining the presence or absence of an occupant on the seat is increased.

  (16) Preferably, in the configuration of (15), the center of the rear detection region, the center of the left front detection region, and the center of the right front detection region are arranged at vertices of an isosceles triangle, The center of the rear detection area is preferably arranged 50 mm ahead of the hip point design point of the seat.

  When the occupant normally sits on the seat, the area around the hip point design point is pressed by the apex of the pubic bone 104c shown in FIG. On the other hand, when the occupant puts out the buttocks about 100 mm forward and sits down on the seat, the area around the front 100 mm of the hip point design point is pressed by the apex of the pubic bone 104 c shown in FIG. In view of this point, the rear detection area of this configuration is set based on the hip point design point. In other words, the center of the rear detection region is arranged at an intermediate point between the hip point design point and the position 100 mm ahead of the hip point. When the occupant gets on the seat, the sensor cell in the rear detection area is pressed to detect the load state, regardless of whether the seating is normal seating or front seating. According to this configuration, not only the discrimination accuracy between adults and child seats but also the discrimination accuracy for vacant seat discrimination is further increased.

  (17) Preferably, in the configuration of (16) above, a perpendicular drawn from the center of the rear detection area to a base connecting the center of the left front detection area and the center of the right front detection area Is set to 50 mm, the distance from the intersection of the perpendicular and the bottom to the center of the left front detection area, and the distance from the intersection to the center of the right front detection area, It is better to have a configuration set to 65 mm.

  That is, this configuration has a center corresponding to the apex of the pubic bone 104c, the apex of the ischial 104a, and the apex of the ischial 104b shown in FIG. The center of the front detection area is set. That is, focusing on the size and shape of the pelvis, the rear detection area, the left front detection area, and the right front detection area are positioned. According to this configuration, the rear detection area, the left front detection area, and the right front detection area can be positioned based on the hip point design point without depending on the size and shape of the seat. For this reason, it is easy to share a load sensor between a plurality of sheets having different specifications.

  (18) Preferably, in the configuration of (17), each of the rear detection area, the left front detection area, and the right front detection area has a side length of 100 mm and a side length of the front and rear direction. It is better to adopt an oval shape inscribed in a 200 mm rectangle.

  That is, in this configuration, the range of the rear detection area, the left front detection area, and the right front detection area positioned in the above (17) is an ellipse inscribed in a rectangle having a predetermined shape. According to this configuration, even if the hip point of the occupant and the hip point design point of the seat are misaligned, it is possible to reliably discriminate between an adult and a child seat.

  Here, the length of the rectangular left and right sides was set to 100 mm and the length of the front and rear sides was set to 200 mm, not only when the adult was seated normally, but also when the adult raised the buttocks forward about 100 mm. This is to ensure that an adult and a child seat are discriminated even when sitting and sitting. Note that the “center” of the detection region in the case where the detection region is an ellipse inscribed in a rectangle as in the present configuration refers to the intersection of the diagonal lines of the rectangle.

  (19) Preferably, in the configuration of (15), the sensor cell in the rear detection region is more sensitive to detect a smaller load than the sensor cell in the left front detection region and the sensor cell in the right front detection region. It is better to have a configured configuration.

  As shown in FIG. 6B, the hatching density of the rear grid is smaller than the hatching density of the left and right front grids. Therefore, the load detected in the rear detection region is smaller than the load detected in the left front detection region and the load detected in the right front detection region. In view of this point, this configuration sets the sensor cell in the rear detection region so that a smaller load can be detected than the sensor cell in the left front detection region and the sensor cell in the right front detection region. That is, in this configuration, sensor cells corresponding to the load characteristics of each detection region are arranged in each detection region. According to this configuration, load detection accuracy is increased. Therefore, the discrimination accuracy between the adult and the child seat and the vacant seat discrimination is increased.

  (20) Preferably, in the configuration of (15), a plurality of sensor cells are arranged in each of the rear detection region, the left front detection region, and the right front detection region. According to this configuration, even if the hip point of the occupant and the hip point design point of the seat are deviated, it is possible to reliably discriminate between an adult and a child seat and to determine an empty seat.

  (21) Preferably, in the configuration of (15) above, the sensor cell may have a configuration in which an output changes according to a load. According to this configuration, not only discrimination between adults and child seats and vacant seat discrimination, but also discrimination between adults and children can be performed relatively easily.

  (22) Preferably, in the configuration of (15), the sensor cell has a membrane switch shape capable of outputting on / off information, and the sensor cell disposed in the rear detection region includes a rear resistor. Are connected in parallel, a left front resistor is connected in parallel to the sensor cell arranged in the left front detection region, and a right front resistor is connected to the sensor cell arranged in the right front detection region. Are preferably connected in parallel. According to this configuration, the manufacturing cost of the sensor cell can be reduced as compared with the above (21).

  (23) Preferably, in the configuration of (22) above, the resistance value of the rear resistor, the resistance value of the left front resistor, and the resistance value of the right front resistor are preferably different. According to this configuration, since the resistance value of the rear resistor, the resistance value of the left front resistor, and the resistance value of the right front resistor are different from each other, the sensor cell in the rear detection region, the sensor cell in the left front detection region, and the right front detection region It is possible to identify which detection region of the sensor cells is on (or whether all three detection regions are on).

  (24) Preferably, in the configuration of (22), the sensor cell and the rear resistor in the rear detection region connected in parallel, and the sensor cell and the left front resistor in the left front detection region connected in parallel It is preferable that the sensor cell and the right front resistor in the right front detection region connected in parallel are connected in parallel.

  That is, in this configuration, the rear detection area, the left front detection area, and the right front detection area are connected in parallel. According to this configuration, when a sensor cell in at least one detection region (at least one sensor cell in the detection region) is turned on among the sensor cells in the three detection regions, the potential upstream of the sensor cell changes.

  (25) Preferably, in the configuration of (22), the sensor cell and the rear resistor in the rear detection region connected in parallel, and the sensor cell and the left front resistor in the left front detection region connected in parallel The sensor cell and the right front resistor that are connected in parallel in the right front detection region are preferably connected in series.

  That is, in this configuration, the rear detection area, the left front detection area, and the right front detection area are connected in series. According to this configuration, when a sensor cell in at least one detection region (at least one sensor cell in the detection region) is turned on among the sensor cells in the three detection regions, the potential upstream of the sensor cell changes.

  (26) Further, the occupant protection system of the present invention includes the load sensor according to (22) above, and the rear detection area, the left front detection area, and the right front detection area based on the output and resistance value of the load sensor. An occupant protection system comprising: an occupant detection ECU that determines an occupant state of the seat based on on / off; and an occupant protection ECU that drives an occupant protection device based on a determination result of the occupant detection ECU; The occupant protection ECU drives the occupant protection device when both the sensor cell in the rear detection region, the sensor cell in the left front detection region, and the sensor cell in the right front detection region are on.

  That is, the occupant protection system according to the present invention determines that an adult is on the seat when the sensor cell in the rear detection area, the sensor cell in the left front detection area, and the sensor cell in the right front detection area are all on, The tool is driven. The occupant protection system of the present invention can reliably discriminate between an adult and a child seat despite having a load sensor with a small number of sensor cells. In addition, the manufacturing cost is low because the number of sensor cells is small. Also, the manufacturing cost is low in that the sensor cell has a membrane switch shape.

  (27) Preferably, in the configuration of (26), further includes a belt tension sensor that detects tension data of a seat belt corresponding to the seat, and the occupant protection ECU includes the sensor cell in the rear detection region and the sensor cell A configuration in which the occupant protection device is driven when both the sensor cell in the left front detection area and the sensor cell in the right front detection area are on and the tension data of the belt tension sensor is less than a predetermined threshold; Better to do.

  As described above, the child seat is fixed to the seat by the seat belt. For this reason, when the child seat is mounted on the seat, the tension data of the belt tension sensor becomes larger than when the adult gets on the seat. Focusing on this point, this configuration uses the tension data of the belt tension sensor to distinguish between adults and child seats. That is, in this configuration, when the sensor cell in the rear detection area, the sensor cell in the left front detection area, and the sensor cell in the right front detection area are all on, and the tension data of the belt tension sensor is less than a predetermined threshold value, the seat It is determined that an adult is on board, and the occupant protection device is driven. According to this structure, the discrimination | determination precision between an adult and a child seat becomes high.

  (28) Further, the occupant protection system of the present invention includes the load sensor according to (22) above, and the rear detection area, the left front detection area, and the right front detection area based on the output and resistance value of the load sensor. An occupant protection ECU that determines an occupant state of the seat based on on / off and drives an occupant protection device based on the determination result, wherein the occupant protection ECU detects the rearward detection When the sensor cell in the region, the sensor cell in the left front detection region, and the sensor cell in the right front detection region are both on, the occupant protection device is driven.

  The occupant protection system of the present invention can reliably discriminate between an adult and a child seat despite having a load sensor with a small number of sensor cells. In addition, the manufacturing cost is low because the number of sensor cells is small. Also, the manufacturing cost is low in that the sensor cell has a membrane switch shape. Further, the occupant protection system of the present invention requires fewer parts compared to the occupant protection system of (26) above, because the occupant detection ECU is not arranged.

  (29) Preferably, in the configuration of (28), further includes a belt tension sensor that detects tension data of a seat belt corresponding to the seat, and the occupant protection ECU includes the sensor cell in the rear detection region and the sensor cell A configuration in which the occupant protection device is driven when both the sensor cell in the left front detection area and the sensor cell in the right front detection area are on and the tension data of the belt tension sensor is less than a predetermined threshold; Better to do. According to this configuration, as described in (27) above, the discrimination accuracy between an adult and a child seat increases.

  According to the present invention, it is possible to provide a load sensor and an occupant protection system that can discriminate between an adult and a child seat at low cost.

  Hereinafter, embodiments of the passenger protection system of the present invention will be described. In addition, the following description serves as description about embodiment of the load sensor of this invention.

<First embodiment>
First, the configuration of the occupant protection system of this embodiment will be described. FIG. 8 shows a transparent perspective view of a seat on which the occupant protection system of the present embodiment is arranged. The direction is defined with reference to the direction from the rear to the front of the vehicle. FIG. 9 shows a block diagram of the passenger protection system.

  As shown in these drawings, the occupant protection system 1 of the present embodiment includes a load sensor 2, an occupant detection ECU 3, and an airbag ECU 4. The airbag ECU 4 is included in the occupant protection ECU of the present invention.

  The load sensor 2 includes sensor cells A1 to A4, B1 to B4, and C1 to C4, and a film member, a conductor, and a connector (not shown). The sensor cells A1 to A4, B1 to B4, and C1 to C4 have a membrane switch shape, and are interposed between an epidermis surface (not shown) of the seat (passenger seat) 5 and a cushion upper surface. Among these, as will be described later, the sensor cells C1 to C4 are arranged in a rear detection region C (indicated by hatching in the drawing) centered about 50 mm ahead of the hip point design point HP. The sensor cells A1 to A4 are arranged in the left front detection area A (indicated by hatching in the figure). Further, the sensor cells B1 to B4 are arranged in the right front detection region B (indicated by hatching in the figure). The sensitivity of the sensor cells C1 to C4 is set so that a smaller load can be detected than the sensor cells A1 to A4 and B1 to B4. The position and range of each detection region and the arrangement of each sensor cell will be described in detail later.

  A film member consists of a branch line part and a trunk line part. The branch line part is formed by branching one end of the main line part. Sensor cells A1 to A4, B1 to B4, and C1 to C4 are arranged in the branch line portion. The trunk portion has a long plate shape. The trunk portion extends from the upper surface of the cushion to the lower surface of the cushion.

  The connector is fixed to a cushion frame (not shown) below the cushion. The other end of the trunk portion of the film member is fixed to the connector. The conductor electrically connects the sensor cells A1 to A4, B1 to B4, and C1 to C4 with the connector.

  The occupant detection ECU 3 is fixed to the lower surface of the seat 5. The occupant detection ECU 3 and the connector are electrically connected via a harness (not shown). The occupant detection ECU 3 includes a CPU 30 and a communication I / F (interface) 31. On / off information of the sensor cells A1 to A4, B1 to B4, and C1 to C4 is transmitted from the load sensor 2 to the RAM of the CPU 30 (not shown). An occupant determination program is stored in the ROM of the CPU 30 (not shown).

  The airbag ECU 4 is disposed below the instrument panel (not shown) and above the floor tunnel (not shown). The airbag ECU 4 and the occupant detection ECU 3 are electrically connected via a harness (not shown). The bag body 40 is embedded in the instrument panel in a folded state. The bag body 40 is included in the occupant protection device of the present invention. The airbag ECU 4 is electrically connected to the bag body 40.

  Next, the structure of the sensor cell of the load sensor of the passenger protection system of this embodiment will be described. FIG. 10 shows a vertical sectional view of the sensor cell A1. (A) shows an insulated state, (b) shows an energized state, respectively. As shown in the drawing, the sensor cell A1 is formed between the upper layer 200U and the lower layer 200D of the branch line portion 20 of the film member. A silver layer 201U is laminated on the lower surface of the upper layer 200U. The silver layer 201U is covered with a carbon layer 202U. A silver layer 201D is laminated on the upper surface of the lower layer 200D so as to face in the vertical direction. The silver layer 201D is covered with a carbon layer 202D. When an occupant sits on the seat, the upper carbon layer 202U bends as indicated by the white arrow in FIG. Further, when the occupant sits down, the seat cushion also bends. For this reason, the lower carbon layer 202D is also bent by the reaction force, as indicated by the white arrow in FIG. The upper carbon layer 202U and the lower carbon layer 202D are in contact with each other. The configurations of the sensor cells A2 to A4, B1 to B4, and C1 to C4 are the same. Therefore, the explanation is omitted.

  Next, the position and range of each detection area and the arrangement of each sensor cell in the passenger protection system of this embodiment will be described. FIG. 11 shows a top view of a seat on which the occupant protection system of the present embodiment is arranged. The seat back is indicated by a two-dot chain line. Each detection area is indicated by hatching.

  As shown in the drawing, the center CO of the rear detection region C is disposed in front of the hip point design point HP by Lhp (= 50 mm). On the other hand, the center AO of the left front detection area A is arranged in front of the center CO of the rear detection area C. Further, the center BO of the right front detection area B is arranged right front of the center CO of the rear detection area C. The center CO, the center AO, and the center BO describe an inverted triangle that spreads toward the front of the seat 5. The length La of the perpendicular drawn from the center CO to the base connecting the center AO and the center BO is set to 50 mm. Further, the distances Lb from the intersection between the base connecting the center AO and the center BO and the perpendicular to the centers AO and BO are set to 65 mm. That is, the center CO, the center AO, and the center BO form an isosceles triangle that spreads toward the front of the seat 5. Each of the rear detection area C, the left front detection area A, and the right front detection area B has a rectangular shape with a side length in the left-right direction Y (= 100 mm) and a length in the front-rear direction side X (= 200 mm) (in the drawing). , Indicated by a dotted line). The centers AO, BO, and CO are located at intersections of rectangular diagonal lines that circumscribe each detection area.

  In the rear detection region C, sensor cells C1 to C4 are arranged. These four sensor cells C1 to C4 are arranged at the vertices of a rectangle that is long in the front-rear direction surrounding the center CO. In the left front detection area A, sensor cells A1 to A4 are arranged. These four sensor cells A1 to A4 are arranged at each vertex of a rectangle that is long in the front-rear direction surrounding the center AO. In addition, sensor cells B1 to B4 are arranged in the right front detection region B. These four sensor cells B1 to B4 are arranged at the vertices of a rectangle that is long in the front-rear direction surrounding the center BO.

  Next, the wiring structure of the load sensor of the passenger protection system of this embodiment will be described. FIG. 12 shows a wiring diagram of the load sensor of the occupant protection system of this embodiment. On the positive electrode side, the sensor cells A1 to A4, B1 to B4, C1 to C4, and the connector are connected by a conductor 21. A resistor Rxy is interposed between the terminals x and y of the conductor 21. The resistance value R of the resistor Rxy is set to 1 kΩ. A voltmeter Vxy is connected in parallel between the terminals x and y. The voltmeter Vxy can detect the voltage between the terminals x and y. On the negative electrode side, the sensor cells A1 to A4, B1 to B4, C1 to C4 and the connector are connected by a conductor 22.

  The sensor cells A1 to A4 in the left front detection area A are connected in parallel. Further, the left front resistor RA is connected in parallel to the sensor cells A1 to A4. The resistance value R of the left front resistor RA is set to 2 kΩ. Similarly, the sensor cells B1 to B4 in the right front detection region B are connected in parallel. Further, the right front resistor RB is connected in parallel to the sensor cells B1 to B4. The resistance value R of the right front resistor RB is set to 4 kΩ. Similarly, the sensor cells C1 to C4 in the rear detection region C are connected in parallel. A rear resistor RC is connected in parallel to the sensor cells C1 to C4. The resistance value R of the rear resistor RC is set to 8 kΩ. Further, the left front detection area A, the right front detection area B, and the rear detection area C are connected in parallel. When any one of the sensor cells A1 to A4, B1 to B4, and C1 to C4 is turned on, it is energized through a path of the conductor 21 → the sensor cell that is turned on → the conductor 22.

  Next, the movement of the passenger protection system of this embodiment will be described. The load of the load on the sheet 5 is detected by any of the sensor cells A1 to A4, B1 to B4, and C1 to C4 being bent and conducting as shown in FIG. 10B. Is done. Specifically, it is detected as the voltage value of the voltmeter Vxy in FIG.

  The detection data is transmitted to the CPU 30 shown in FIG. By the way, as described above, the resistance value of the left front resistor RA (R = 2 kΩ), the resistance value of the right front resistor RB (R = 4 kΩ), and the resistance value of the rear resistor RC (R = 8 kΩ) Are different. For this reason, from the voltage value of the voltmeter Vxy, it can be determined which sensor cell of which detection region is turned on among the left front detection region A, the right front detection region B, and the rear detection region C. The CPU 30 determines from this voltage value whether the seat 5 is empty or whether the load on the seat 5 is an adult or a child seat.

  Specifically, when the off information is transmitted from the sensor cell in the left front detection area A, the off information is transmitted from the sensor cell in the right front detection area B, and the off information is transmitted from the sensor cell in the rear detection area C, the seat 5 Is determined to be empty. Further, when the on-information is transmitted from the sensor cell in the rear detection area C (at least one of the sensor cells C1 to C4 only needs to be turned on), it is determined that there is an occupant in the seat 5. On information is transmitted from the sensor cells in the left front detection area A (at least one of the sensor cells A1 to A4 only needs to be turned on), and on information is transmitted from the sensor cells in the right front detection area B (sensor cell B1). When at least one sensor cell among B4 is turned on), when on-information is transmitted from the sensor cell in the rear detection region C, it is determined that an adult is on the seat 5. In cases other than the above, it is determined that the child seat is mounted on the seat 5.

  The determination result is transmitted from the CPU 30 to the airbag ECU 4 via the communication I / F 31. The airbag ECU 4 issues an instruction to the bag body 40 based on the determination result. Specifically, in the case of “vacant seat” determination and “child seat” determination, the bag body 40 is set in a deployment prohibited state. Only in the case of “adult” determination, the bag body 40 is deployed according to the acceleration (deceleration) of the vehicle.

  Next, functions and effects of the passenger protection system and the load sensor according to the present embodiment will be described. The sensor cells A1 to A4, B1 to B4, and C1 to C4 of the load sensor 2 of this embodiment are based on the analysis and consideration of the inventor shown in FIG. Are arranged in a left front detection area A, a right front detection area B, and a rear detection area C each having a center in a large area. For this reason, it is not necessary to arrange sensor cells over the entire surface of the sheet 5. Therefore, the number of sensor cells arranged can be reduced. That is, the manufacturing cost of the load sensor 2 can be reduced.

  Further, the sensor cells A1 to A4, B1 to B4, and C1 to C4 are arranged in an area most effective for determining the occupant state of the seat 5. For this reason, although there are few sensor cell arrangement | positioning numbers, an adult and a child seat can be discriminate | determined reliably.

  In addition, the load on the sensor cells C <b> 1 to C <b> 4 in the rear detection region C is likely to appear when the occupant gets on the seat 5. For this reason, the determination accuracy of the vacant seat determination for determining the presence or absence of a passenger on the seat 5 is increased.

  In addition, the sensor cells A1 to A4, B1 to B4, and C1 to C4 of the load sensor 2 of the present embodiment are arranged based on the hip point design point HP of the seat 5. Specifically, the center CO is arranged in front of Lhp (= 50 mm) from the hip point design point HP. For this reason, according to the load sensor 2 of the present embodiment, the discrimination accuracy between the adult and the child seat is high regardless of whether the seating is normal seating or front seating.

  Further, the positions and ranges of the left front detection area A, the right front detection area B, and the rear detection area C of the load sensor 2 of the present embodiment are the actual sizes based on the hip point HP (Lhp = 50 mm in FIG. La = 50 mm, Lb = 65 mm, Y = 100 mm, X = 200 mm). For this reason, it is easy to share a load sensor between a plurality of sheets having different specifications. Further, even if the occupant's hip point and the hip point design point of the seat deviate from each other, the discrimination between the adult and the child seat and the vacant seat discrimination can be surely performed.

  In addition, the sensitivity of the sensor cells C1 to C4 of the load sensor 2 of the present embodiment is set so that a smaller load can be detected than the sensor cells A1 to A4 and B1 to B4. For this reason, load detection accuracy is high. Therefore, the discrimination accuracy between the adult and the child seat and the vacant seat discrimination is increased.

  In the left front detection area A, the right front detection area B, and the rear detection area C, four sensor cells A1 to A4, B1 to B4, and C1 to C4 are arranged, respectively. For this reason, even if the hip point of the occupant and the hip point design point of the seat deviate from each other, it is possible to reliably discriminate between an adult and a child seat and vacant seat.

  Further, according to the load sensor 2 of the present embodiment, as shown in FIG. 12, the sensor cells A1 to A4 and the left front resistor RA, the sensor cells B1 to B4 and the right front resistor RB, the sensor cells C1 to C4 and the rear resistor Each body RC is connected in parallel. In addition, the resistance value of the left front resistor RA, the resistance value of the right front resistor RB, and the resistance value of the rear resistor RC are different. For this reason, of the sensor cells C1 to C4 in the rear detection area C, the sensor cells A1 to A4 in the left front detection area A, and the sensor cells B1 to B4 in the right front detection area B, which sensor area is on (or three Whether two detection areas are on).

  Further, according to the passenger protection system 1 of the present embodiment, when the sensor cells C1 to C4 in the rear detection area C, the sensor cells A1 to A4 in the left front detection area A, and the sensor cells B1 to B4 in the right front detection area B are all on. Then, it is determined that an adult is on the seat 5, and the bag 40 is deployed. For this reason, despite having the load sensor 2 with a small number of sensor cells, it is possible to reliably distinguish an adult from a child seat. In addition, the manufacturing cost is low because the number of sensor cells is small. Also, the manufacturing cost is low in that the sensor cell has a membrane switch shape.

  Further, according to the passenger protection system 1 of the present embodiment, the rear detection area C, the left front detection area A, and the right front detection area B each have an oval shape. For this reason, not only when an adult is seated normally, but also when an adult sits forward with the buttocks out, the adult and the child seat can be reliably discriminated.

<Second embodiment>
The difference between the present embodiment and the first embodiment is that a belt tension sensor is connected to the occupant detection ECU. Therefore, only the differences will be described here.

In FIG. 13, the block diagram of the passenger | crew protection system of this embodiment is shown. In addition, about the site | part corresponding to FIG. 9, it shows with the same code | symbol. As shown in the figure, the belt tension sensor 6 is connected to the CPU 30. The belt tension sensor 6 detects seat belt tension data corresponding to the seat on which the load sensor 2 is disposed. A tension threshold value T _th (= 50 N) is stored in the ROM of the CPU 30. When the detected tension data is equal to or greater than the tension threshold value T _th , the CPU 30 determines that the child seat is fixed to the seat. On the other hand, when the detected tension data is less than the tension threshold value T _th and all the ON information is transmitted from the sensor cell in the left front detection area A, the sensor cell in the right front detection area B, and the sensor cell in the rear detection area C The CPU 30 determines that an adult is on the seat.

  The occupant protection system 1 and the load sensor 2 of the present embodiment have the same effects as the occupant protection system and the load sensor of the first embodiment. In the case of the occupant protection system 1 of the present embodiment, the belt tension sensor 6 is used for occupant discrimination. For this reason, the discrimination accuracy between an adult and a child seat increases.

<Third embodiment>
The difference between the present embodiment and the second embodiment is that no rear detection area is set. Therefore, only the differences will be described here.

  In FIG. 14, the block diagram of the passenger | crew protection system of this embodiment is shown. In addition, about the site | part corresponding to FIG. 13, it shows with the same code | symbol. As shown in the figure, the CPU 30 is connected with sensor cells A1 to A4 in the left side detection area A, sensor cells B1 to B4 in the right side detection area, a belt tension sensor 6, and a communication I / F 31. .

When the tension data detected by the belt tension sensor 6 is equal to or greater than the tension threshold value _Tth , the CPU 30 determines that the child seat is fixed to the seat. On the other hand, when the detected tension data is less than the tension threshold value T _th and both the ON information is transmitted from the sensor cell in the left front detection area A and the sensor cell in the right front detection area B, the CPU 30 detects that the adult is on the seat. It is determined that you are on board.

  The occupant protection system 1 and the load sensor 2 of this embodiment have the same effects as the occupant protection system and the load sensor of the second embodiment. In the case of the load sensor 2 of the present embodiment, no rear detection area is set. For this reason, the number of sensor cells arranged can be reduced. That is, the manufacturing cost of the load sensor 2 and thus the occupant protection system 1 can be reduced.

<Fourth embodiment>
The difference between the present embodiment and the second embodiment is that the rear detection area is set larger than the left front detection area and the right front detection area. Therefore, only the differences will be described here.

  FIG. 15 shows a top view of a seat on which the occupant protection system of this embodiment is arranged. In addition, about the site | part corresponding to FIG. 11, it shows with the same code | symbol. As shown in the figure, the rear detection area C is inscribed in a rectangle (shown by a dotted line in the figure) having a side length of Y1 (= 80 mm) and a side length of X1 (= 180 mm) in the front-rear direction. It has an oval shape. Each of the left front detection area A and the right front detection area B is a rectangle having a side length Y2 (= 50 mm) and a side length X2 (= 150 mm) (dotted line in the figure). It shows an oval shape inscribed in (shown). The centers AO, BO, and CO are located at intersections of rectangular diagonal lines that circumscribe each detection area.

  The occupant protection system and load sensor 2 of this embodiment have the same effects as the occupant protection system and load sensor of the second embodiment. Moreover, the total area of the detection area | region of the load sensor 2 of this embodiment is smaller than the total area of each detection area | region of the load sensor of 2nd embodiment. For this reason, the manufacturing cost of the load sensor 2 and thus the occupant protection system is low.

<Fifth embodiment>
The difference between the present embodiment and the second embodiment is that the wiring structure of the load sensor is connected in series. Therefore, only the differences will be described here.

  FIG. 16 shows a wiring diagram of the load sensor of the occupant protection system of this embodiment. In addition, about the site | part corresponding to FIG. 12, it shows with the same code | symbol. As shown in the figure, the left front detection area A, the right front detection area B, and the rear detection area C are connected in series. Further, the resistance value of the resistor Rxy, the resistance value of the left front resistor RA, the resistance value of the right front resistor RB, and the resistance value of the rear resistor RC are each set to 1 kΩ. When any one of the sensor cells A1 to A4 and any one of the sensor cells B1 to B4 and any one of the sensor cells C1 to C4 are turned on, the conductor 21 → the sensor cells A1 to A4. The sensor cell turned on, the sensor cell turned on among the sensor cells B1 to B4, the sensor cell turned on among the sensor cells C1 to C4, and the conductor 22 are energized.

  The occupant protection system and load sensor 2 of this embodiment have the same effects as the occupant protection system and load sensor of the second embodiment.

<Others>
The embodiments of the occupant protection system and the load sensor of the present invention have been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  For example, three detection regions are set in the first, second, fourth, and fifth embodiments, and two detection regions are set in the third embodiment. However, the number of detection areas set is not particularly limited. Further, the position of the detection region is not particularly limited. It suffices if the center of the detection region is in a region where the difference between the load distribution when the child seat is mounted and the load distribution when the adult is on board is large.

  Further, the number and position of sensor cells in each detection region are not particularly limited. In the above-described embodiments, the membrane switch type sensor cells A1 to A4, B1 to B4, and C1 to C4 are all arranged. However, the sensor cell type (for example, pressure-sensitive ink type sensor cell) whose output changes according to the load. ) May be arranged. This increases the occupant discrimination accuracy. A membrane switch type sensor cell and a sensor cell whose output changes depending on the load may be used in combination.

  Moreover, in said 1st embodiment, discrimination | determination between an adult and a child seat was performed from the output of the load sensor 2 and the output of the load sensor 2 and the belt tension sensor 6 in 2nd-5th embodiment. However, it is also possible to distinguish between an adult and a child seat by adding outputs from the image sensor and other load sensors on the seat rail to the sensor output.

  Further, in the above embodiment, the occupant detection ECU 3 is arranged, but the function of the occupant detection ECU 3 may be integrated into the airbag ECU 4 to be a single ECU. Needless to say, the left front resistor RA, the right front resistor RB, and the rear resistor RC in the above embodiment function as a diagnosis (fault diagnosis) resistor.

  In the first to fourth embodiments, the resistance value of the left front resistor RA, the resistance value of the right front resistor RB, and the resistance value of the rear resistor RC are different from each other. Good. In this case, at least “adult” and “child seat” can be discriminated. Further, since the resistor can be used in common, the manufacturing cost of the load sensor and thus the occupant protection system is reduced.

Further, the values of Lhp, La, Lb, X, Y, X1, Y1, X2, and Y2 in the above embodiment (see FIGS. 11 and 15 above), the values of Rxy, RA, RB, and RC (see FIG. 12 above). The tension threshold value T _th in the second to fifth embodiments is not particularly limited.

  In the above embodiment, the airbag ECU 4 is used as the occupant protection ECU and the bag body 40 is used as the occupant protection device. However, the types of the occupant protection ECU and the occupant protection device are not particularly limited. For example, a pretensioner ECU may be used as the occupant protection ECU, and a seat belt pretensioner may be used as the occupant protection tool.

  In the first and second embodiments, the “vacant seat” determination is performed by the sensor cells C1 to C4 in the rear detection region C. However, “child” discrimination may be performed. That is, when an adult sits on the seat 5, all of the left front detection area A, the right front detection area B, and the rear detection area C are turned on. For this reason, when only the rear detection area C is on, it can be determined that the passenger is a child.

In the second to fifth embodiments, the belt tension sensor 6 detects the tension data of the seat belt, and the tension threshold T _th set in the ROM of the CPU 30 of the occupant detection ECU 3 and the detected tension. The passenger is identified by comparing the data. However, these functions may be integrated, and the belt tension sensor may be an on / off switch. Specifically, the belt tension sensor may be an on / off switch that is turned off when the tension threshold value T ′ _{th is} greater than a certain tension threshold value T ′ _th and turned on when the belt tension sensor is less than the tension threshold value T ′ _th .

Further, when the belt tension sensor is the above-mentioned on / off switch, the belt tension sensor and a load sensor (see FIG. 16) in which each detection region is connected in series may be connected in series. In this configuration, when the tension data is equal to or greater than the tension threshold value _T′th , the belt tension sensor is turned off, and the circuit is opened regardless of whether the load sensor is turned on or off. At this time, it is determined that the child seat is fixed to the seat 5, the child is on the seat 5, or the seat 5 is empty.

On the other hand, when the tension data is less than the tension threshold value _T′th , the belt tension sensor is turned on. In this case, the determination is changed by turning on / off the load sensor. One of the sensor cells A1 to A4 in the left front detection area A, one of the sensor cells B1 to B4 in the right front detection area B, and one of the sensor cells C1 to C4 in the rear detection area C However, when all are turned on, it is determined that an adult is on the seat 5. On the contrary, when all the sensor cells in at least one detection area are off, it is determined that the child seat is fixed to the seat 5, the child is on the seat 5, or the seat 5 is empty.

  As described above, according to the configuration in which the on / off belt tension sensor and the load sensor (see FIG. 16 above) in which the detection areas are connected in series are connected in series, adult discrimination is possible without using the CPU 30. become. Accordingly, the occupant detection ECU 3 can be eliminated. That is, the manufacturing cost of the passenger protection system 1 can be reduced.

It is a side view of the sheet | seat which mounts a child seat. (A) is a schematic diagram of a child seat having ribs extending in the front-rear direction. (B) is a grid diagram showing a pressure distribution of a seat on which the child seat is mounted. (A) is a schematic diagram of the child seat with the rib extended in the left-right direction. (B) is a grid diagram showing a pressure distribution of a seat on which the child seat is mounted. (A) is a schematic diagram of a child seat having a U-shaped rib. (B) is a grid diagram showing a pressure distribution of a seat on which the child seat is mounted. It is a side view of the sheet | seat which the adult boarded. (A) is a schematic diagram of an adult pelvis. (B) is a grid diagram showing a pressure distribution of a seat on which an adult is boarded. It is a grid figure which shows the pressure difference distribution of the pressure distribution of the sheet | seat at the time of child seat mounting, and the pressure distribution of the sheet | seat at the time of adult boarding. It is a permeation | transmission perspective view of the sheet | seat in which the passenger | crew protection system of 1st embodiment is arrange | positioned. It is a block diagram of the passenger protection system. It is an up-down direction sectional view of a sensor cell of a load sensor of the crew protection system. It is a top view of the sheet | seat in which the passenger protection system is arrange | positioned. It is a wiring diagram of the load sensor of the passenger protection system. It is a block diagram of a crew member protection system of a second embodiment. It is a block diagram of a crew member protection system of a third embodiment. It is a top view of the sheet | seat in which the passenger | crew protection system of 4th embodiment is arrange | positioned. It is a wiring diagram of the load sensor of the passenger | crew protection system of 5th embodiment.

Explanation of symbols

  1: occupant protection system, 2: load sensor, 20: branch line portion, 200U: upper layer, 200D: lower layer, 201U: silver layer, 201D: silver layer, 202U: carbon layer, 202D: carbon layer, 21: conductor, 22: Conductor, 3: occupant detection ECU, 30: CPU, 31: communication I / F, 4: airbag ECU (occupant protection ECU), 40: bag body (occupant protection device), 5: seat, 6: belt tension sensor.

  A: Left front detection area, A1 to A4: Sensor cell, B: Right front detection area, B1 to B4: Sensor cell, C: Rear detection area, C1 to C4: Sensor cell, RA: Left front resistor, RB: Right front resistance Body, RC: Back resistor, HP: Hip point design point.

Claims (29)

A load sensor for detecting a load state of a vehicle seat by a sensor cell disposed on the seat,
In the seat, the center of the detection region is set in at least one region selected from a region having a large difference between the load distribution when the child seat is mounted and the load distribution when riding an adult,
A load sensor, wherein at least one sensor cell is disposed in the detection region.   The left front detection region and the right front detection region are set in the seat as the detection region in front of the hip point design point of the seat and symmetrically in the seat vehicle width direction. The load sensor described. The length of the perpendicular drawn from the hip point design point to the straight line connecting the center of the left front detection area and the center of the right front detection area is set to 100 mm,
The load sensor according to claim 2, wherein the distance from the intersection of the perpendicular and the straight line to each of the centers is set to 65 mm.   The left front detection region and the right front detection region each have an oval shape inscribed in a rectangle having a length of 100 mm in the left-right direction and a length of 200 mm in the front-rear direction. Load sensor.   The load sensor according to claim 2, wherein a plurality of the sensor cells are arranged in each of the left front detection region and the right front detection region.   The load sensor according to claim 2, wherein an output of the sensor cell changes according to a load. The sensor cell has a membrane switch shape capable of outputting on / off information,
A left front resistor is connected in parallel to the sensor cell arranged in the left front detection region,
The load sensor according to claim 2, wherein a right front resistor is connected in parallel to the sensor cell arranged in the right front detection region.   The load sensor according to claim 7, wherein a resistance value of the left front resistor is different from a resistance value of the right front resistor.   The sensor cell and the left front resistor in the left front detection region connected in parallel and the sensor cell and the right front resistor in the right front detection region connected in parallel are connected in parallel. The load sensor described.   The sensor cell and the left front resistor in the left front detection region connected in parallel and the sensor cell and the right front resistor in the right front detection region connected in parallel are connected in series. The load sensor described. The load sensor according to claim 7, and an occupant detection ECU that determines an occupant state of the seat based on on / off of the left front detection region and the right front detection region from an output and a resistance value of the load sensor, An occupant protection ECU that drives an occupant protection device based on a determination result of the occupant detection ECU, and an occupant protection system comprising:
The occupant protection ECU drives the occupant protection device when both the sensor cell in the left front detection region and the sensor cell in the right front detection region are on. Furthermore, a belt tension sensor for detecting tension data of a seat belt corresponding to the seat is provided,
When the sensor cell in the left front detection area and the sensor cell in the right front detection area are both on and the tension data of the belt tension sensor is less than a predetermined threshold, the occupant protection ECU The occupant protection system according to claim 11, wherein the occupant protection system is driven. The occupant state of the seat is determined on the basis of the load sensor according to claim 7 and on / off of the left front detection area and the right front detection area from the output and resistance value of the load sensor, and based on the determination result An occupant protection ECU for driving an occupant protection device, and an occupant protection system comprising:
The occupant protection ECU drives the occupant protection device when both the sensor cell in the left front detection region and the sensor cell in the right front detection region are on. Furthermore, a belt tension sensor for detecting tension data of a seat belt corresponding to the seat is provided,
When the sensor cell in the left front detection area and the sensor cell in the right front detection area are both on and the tension data of the belt tension sensor is less than a predetermined threshold, the occupant protection ECU The occupant protection system according to claim 13, wherein the occupant protection system is driven.   The back detection area, the left front detection area, and the right front detection area are set to the seat as the detection area, with each vertex of an inverted triangle spreading toward the front of the seat as a center. Load sensor. The center of the rear detection area and the center of the left front detection area and the center of the right front detection area are arranged at the vertices of an isosceles triangle,
The load sensor according to claim 15, wherein the center of the rear detection region is arranged 50 mm ahead of the hip point design point of the seat. The length of a perpendicular drawn from the center of the rear detection area to the bottom connecting the center of the left front detection area and the center of the right front detection area is set to 50 mm,
The distance from the intersection of the perpendicular and the base to the center of the left front detection area, and the distance from the intersection to the center of the right front detection area are each set to 65 mm. Load sensor.   Each of the rear detection area, the left front detection area, and the right front detection area has an oval shape inscribed in a rectangle having a side length of 100 mm and a side length of 200 mm. Item 18. The load sensor according to Item 17.   The load sensor according to claim 15, wherein the sensitivity of the sensor cell in the rear detection area is set so that a small load can be detected than the sensor cell in the left front detection area and the sensor cell in the right front detection area.   The load sensor according to claim 15, wherein a plurality of the sensor cells are arranged in each of the rear detection area, the left front detection area, and the right front detection area.   The load sensor according to claim 15, wherein an output of the sensor cell changes according to a load. The sensor cell has a membrane switch shape capable of outputting on / off information,
A rear resistor is connected in parallel to the sensor cell arranged in the rear detection region,
A left front resistor is connected in parallel to the sensor cell arranged in the left front detection region,
The load sensor according to claim 15, wherein a right front resistor is connected in parallel to the sensor cell arranged in the right front detection region.   The load sensor according to claim 22, wherein a resistance value of the rear resistor, a resistance value of the left front resistor, and a resistance value of the right front resistor are different.   The sensor cell and the rear resistor in the rear detection region connected in parallel, the sensor cell and the left front resistor in the left front detection region connected in parallel, and the sensor cell in the right front detection region connected in parallel The load sensor according to claim 22, wherein the right front resistor is connected in parallel.   The sensor cell and the rear resistor in the rear detection region connected in parallel, the sensor cell and the left front resistor in the left front detection region connected in parallel, and the sensor cell in the right front detection region connected in parallel The load sensor according to claim 22, wherein the right front resistor is connected in series. 23. The occupant state of the seat is determined based on on / off of the rear detection area, the left front detection area, and the right front detection area from the load sensor according to claim 22 and the output and resistance value of the load sensor. An occupant protection system comprising: an occupant detection ECU; and an occupant protection ECU that drives an occupant protection device based on a determination result of the occupant detection ECU;
The occupant protection ECU is configured to drive the occupant protection device when both the sensor cell in the rear detection region, the sensor cell in the left front detection region, and the sensor cell in the right front detection region are on. Furthermore, a belt tension sensor for detecting tension data of a seat belt corresponding to the seat is provided,
The occupant protection ECU is configured such that both the sensor cell in the rear detection region, the sensor cell in the left front detection region, and the sensor cell in the right front detection region are on, and the tension data of the belt tension sensor is predetermined. 27. The occupant protection system according to claim 26, wherein the occupant protection device is driven when it is less than a threshold value. An occupant state of the seat is determined based on on / off of the rear detection area, the left front detection area, and the right front detection area from the load sensor according to claim 22, and an output and a resistance value of the load sensor. An occupant protection ECU that drives an occupant protection device based on the determination result,
The occupant protection ECU is configured to drive the occupant protection device when both the sensor cell in the rear detection region, the sensor cell in the left front detection region, and the sensor cell in the right front detection region are on. Furthermore, a belt tension sensor for detecting tension data of a seat belt corresponding to the seat is provided,
The occupant protection ECU is configured such that both the sensor cell in the rear detection region, the sensor cell in the left front detection region, and the sensor cell in the right front detection region are on, and the tension data of the belt tension sensor is predetermined. The occupant protection system according to claim 28, wherein the occupant protection device is driven when the threshold value is less than a threshold value.

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