JP2015131549A - Seating state determination device and air bag system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seating state determination device which does not need difficult maintenance, has an inexpensive structure, and is less likely to cause false recognition.SOLUTION: A seating state determination device is used to determine a seating state in a seat 10 at a vehicle including the seat 10 and a seat belt mechanism 20. The seating state determination device includes: a displacement sensor 50 capable of detecting vertical displacement of each S shaped spring 44 supporting a cushion pad 30 relative to a support frame 42 supporting the cushion pad 30 of the seat 10; a belt drawing sensor 60 capable of detecting whether or not predetermined length or more of a belt 21 of the seat belt mechanism 20 is drawn from an initial state; and a determination processing part 70 which determines the seating state on the seat 10 on the basis of the displacement detected by the displacement sensor 50 and a detection result of the belt drawing sensor 60 and outputs an output signal indicating the seating state.

Description

  The present invention relates to an airbag system provided in a vehicle, and more particularly to a seating state discriminating apparatus that discriminates a seating state of a seat used for airbag deployment control.

  Conventionally, an airbag system for protecting an occupant at the time of a vehicle collision is known. Regarding the operation of this airbag system, for example, US Federal Vehicle Safety Standard FMVSS208 is based on whether a passenger is seated in the seat or whether a child seat (Child Restraint System (CRS)) is installed in the seat. Therefore, it is required to control the deployment / non-deployment of the airbag.

  Specifically, when the CRS is installed in the seat, it is necessary not to operate the airbag, but to operate and deploy the airbag when an occupant is sitting on the seat. In order to realize such deployment / non-deployment of an airbag, it is necessary to determine whether an occupant is sitting on the seat, a CRS is installed, or no one is sitting.

  In order to make such a determination, a method using a strain gauge sensor attached to a leg portion of a seat frame is known (for example, see Patent Document 1). In this method, the weight of the load on the seat is measured by a strain gauge attached to the leg portion of the seat frame, and whether the occupant is sitting on the seat based on the CRS reference weight and the occupant reference weight It is determined whether it is installed or no one is sitting.

  However, in this method, it is necessary to attach two to four strain gauges to the leg portion of the seat frame, and there is a problem that the cost of the entire system increases.

  Another method is known in which a capacitance sensor in which electrodes are arranged in a membrane film is embedded in a seat (for example, see Patent Document 2). In this method, the dielectric constant of the load on the seat is detected by applying an AC voltage to the electrode, and whether the occupant is seated in the seat or the CRS is installed based on the detected dielectric constant Or whether no one is sitting.

  However, since the above-described capacitance sensor reacts sensitively even if the elements constituting the sensor are slightly changed, accurate measurement can be performed unless the maintenance and management of the membrane film and electrodes are performed at a high level. difficult. Further, since the determination is made based on the dielectric constant, a plastic bottle containing water may be erroneously recognized as an occupant.

JP 2001-91347 A JP 2006-10490 A

  The present invention has been made in view of the above-described problems of the prior art, and is capable of accurately determining the seating state of a seat with an inexpensive configuration without requiring difficult maintenance. It is a first object to provide

  A second object of the present invention is to provide an airbag system that can appropriately deploy an airbag according to the seating state of the seat.

  According to the first aspect of the present invention, there is provided a seating state determination device capable of accurately determining the seating state of a seat with an inexpensive configuration without requiring difficult maintenance. This seating state discriminating device is used for discriminating the seating state in the seat in a vehicle including a seat and a seat belt mechanism for restraining an occupant seated in the seat with a belt. The seating state determination device includes a displacement sensor capable of detecting a vertical displacement of the cushion pad with respect to a support frame that supports the cushion pad of the seat or a vertical displacement of a spring that supports the cushion pad, and the seat belt. Based on a belt withdrawal sensor capable of detecting whether or not the belt of the mechanism has been pulled out by a predetermined length or more from an initial state, the displacement detected by the displacement sensor, and a detection result of the belt withdrawal sensor, the seat And a discrimination processing unit that discriminates the upper seating state and outputs an output signal indicating the seating state.

  The determination processing unit may include a storage device that stores a predetermined first displacement threshold and a second displacement threshold. In this case, the discrimination processing unit compares the displacement detected by the displacement sensor with the first displacement threshold and the second displacement threshold, and the detected displacement is more than the first displacement threshold. If it is smaller, an output signal indicating the first seating state may be output. When the detected displacement is larger than the second displacement threshold, an output signal indicating the second seating state may be output. When the detected displacement is between the first displacement threshold and the second displacement threshold, the belt withdrawal sensor has detected that the belt has not been withdrawn for a predetermined length or more. If the output signal indicating the third seating state is output, and the detection result of the belt pull-out sensor indicates that the belt has been pulled out more than the predetermined length, An output signal indicating the seating state 4 may be output.

  The output signal indicating the first seating state may indicate that no occupant is seated on the seat, and the output signal indicating the second seating state is seated on the seat. It may be a signal indicating this. The output signal indicating the third seating state may be a signal indicating that an occupant is seated in the seat, and the child seat is installed in the seat as the output signal indicating the fourth seating state. It may be a signal indicating this.

  The displacement sensor is preferably fixed relatively to the support frame. Further, the seating state determination device may further include a magnet fixed to the bottom surface of the cushion pad or the spring. A magnetic sensor that detects the displacement of the cushion pad or the displacement of the spring based on a change in the magnetic field generated by the magnet may be used as the displacement sensor.

  The belt pull-out sensor may detect that the belt has been pulled more than the predetermined length by detecting a slit formed in the belt. Alternatively, the belt pull-out sensor detects that the belt has been pulled more than the predetermined length by detecting the thickness of the belt wound on the retractor reel that winds the belt. Also good.

  According to the 2nd aspect of this invention, the airbag system which can expand | deploy an airbag appropriately according to the seating state of a seat is provided. The airbag system controls the operation of the airbag based on output signals from an airbag for protecting an occupant seated in a seat, the seating state determination device, and a determination processing unit of the seating state determination device. And an airbag control unit.

  According to the 3rd aspect of this invention, the airbag system which can expand | deploy an airbag appropriately according to the seating state of a seat is provided. The airbag system includes an airbag for protecting an occupant seated in a seat, a plurality of inflators that generate gas for deploying the airbag by igniting a gas generating agent, and ignition of the inflator. An airbag control unit for controlling, a displacement sensor capable of detecting a vertical displacement of the cushion pad relative to a support frame supporting the cushion pad of the seat or a vertical displacement of a spring supporting the cushion pad, and a seat belt Based on the belt withdrawal sensor capable of detecting whether or not the belt of the mechanism has been pulled out by a predetermined length or more from the initial state, the displacement detected by the displacement sensor and the detection result of the belt withdrawal sensor, And a discrimination processing unit that discriminates the seating state of the vehicle and outputs an output signal indicating the seating state. The discrimination processing unit includes a storage device that stores a predetermined first displacement threshold and a second displacement threshold. The discrimination processing unit compares the displacement detected by the displacement sensor with the first displacement threshold value and the second displacement threshold value, and when the detected displacement is smaller than the first displacement threshold value. When the detected displacement is larger than the second displacement threshold, an output signal indicating the second seating state is output. When the detected displacement is between the first displacement threshold value and the second displacement threshold value, the discrimination processing unit has a detection result of the belt withdrawal sensor equal to or longer than the predetermined length. If the signal indicates that the belt is not pulled out, an output signal indicating the third seating state is output, and the detection result of the belt pull-out sensor indicates that the belt is pulled out more than the predetermined length. If so, an output signal indicating the fourth seating state is output. The airbag control unit does not ignite any of the plurality of inflators when the output signal from the discrimination processing unit indicates the first seating state or the fourth seating state, and the discrimination is performed. When the output signal from the processing unit indicates the third seating state, n inflators among the plurality of inflators are ignited, and the output signal from the determination processing unit is the second seating state. , More than n inflators among the plurality of inflators are ignited.

  According to the seating state discriminating apparatus according to the present invention, the seating state of the seat can be accurately discriminated with an inexpensive configuration without requiring difficult maintenance. In other words, since the seating state on the seat can be determined by combining the displacement detected by the displacement sensor and the detection result of the belt withdrawal sensor, an expensive strain gauge or a capacitance sensor is required as in the past. And not. Further, unlike the conventional capacitance sensor, difficult maintenance such as maintenance and management of the membrane film and the electrode is not required. Furthermore, since the displacement detected by the displacement sensor and the detection result of the belt withdrawal sensor are combined, a plastic bottle containing water is not erroneously identified as an occupant.

  Further, according to the airbag system of the present invention, since the airbag is controlled based on the seating state determined by the seating state determination device, the airbag is appropriately deployed according to the seating state of the seat. be able to.

It is a mimetic diagram showing an air bag system in a 1st embodiment of the present invention. It is a perspective view which shows typically the seat support part of the state which removed the cushion pad of the seat in the airbag system of FIG. It is a figure which shows typically the III-III sectional view of FIG. It is a figure which shows typically the seat support part of the state in which the passenger | crew sat down on the seat. It is a schematic diagram which shows the belt withdrawal sensor of the airbag system of FIG. 1 with a seat belt mechanism. FIG. 6 is a plan view schematically showing a relationship between a belt withdrawal sensor and a belt in FIG. 5. It is a figure which shows typically a part of belt used in the 1st Embodiment of this invention. FIG. 6 is a schematic diagram showing a state in which the belt is pulled out by a predetermined length in FIG. 5. It is a flowchart which shows the drawer | drawing-out detection process in the belt drawer sensor of FIG. It is a flowchart which shows the seating state discrimination | determination process in the discrimination | determination process part of the airbag system of FIG. It is a schematic diagram which shows the belt extraction sensor in the 2nd Embodiment of this invention with a seatbelt mechanism. FIG. 12 is a plan view schematically showing the relationship between the belt withdrawal sensor and the belt of FIG. 11. FIG. 12 is a plan view schematically showing the relationship between the belt withdrawal sensor and the belt of FIG. 11.

  Hereinafter, embodiments of an airbag system and a seating state determination device according to the present invention will be described in detail with reference to FIGS. 1 to 13. 1 to 13, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic diagram showing an airbag system 100 according to the first embodiment of the present invention. As shown in FIG. 1, an airbag system 100 according to this embodiment includes an airbag 12 provided corresponding to a seat 10, and two inflators 14 </ b> A that supply the high-pressure gas to the airbag 12 and deploy the airbag 12. , 14B, an impact detection sensor 16 for detecting an impact caused by a vehicle collision or the like, and an airbag control unit 18 for controlling the operation of the inflators 14A, 14B. Each of the inflators 14 </ b> A and 14 </ b> B includes an igniter and a gas generating agent, and is connected to the airbag control unit 18. Further, the impact detection sensor 16 can be constituted by one or more acceleration sensors, for example, and is connected to the airbag control unit 18.

  Inflator 14A, 14B will act | operate an igniter and will ignite a gas generating agent, if the signal (airbag deployment signal) which instruct | indicates deployment of the airbag 12 from the airbag control part 18 is received. A high pressure gas is generated by a chemical reaction of the ignited gas generating agent, and the high pressure gas is supplied to the airbag 12 so that the airbag 12 is deployed. In the present embodiment, two inflators 14A and 14B are provided, and the deployment speed of the airbag 12 can be adjusted in two stages. That is, when an airbag deployment signal is transmitted from the airbag control unit 18 to both the inflators 14A and 14B, high-pressure gas is supplied from both the inflators 14A and 14B to the airbag 12, and the deployment speed of the airbag 12 is increased. If the airbag deployment signal is transmitted to only one of the inflators 14A and 14B, the amount of high-pressure gas supplied to the airbag 12 decreases, and the deployment speed of the airbag 12 decreases.

  Further, as shown in FIG. 1, the airbag system 100 is in a seated state of the seat 10 (whether an occupant is seated in the seat 10, a CRS is installed, or no one is seated). A discrimination processing unit 70 that discriminates and outputs an output signal indicating the seating state is provided. The discrimination processing unit 70 includes a memory 72 that stores a threshold value and the like described later. The discrimination processing unit 70 is connected to the airbag control unit 18, and an output signal indicating the seating state of the seat 10 is input from the discrimination processing unit 70 to the airbag control unit 18. The airbag control unit 18 transmits an airbag deployment signal to one or both of the inflators 14A and 14B described above based on the output signal from the discrimination processing unit 70 and the output signal from the impact detection sensor 16. Details of this will be described later.

  As shown in FIG. 1, the airbag system 100 includes a seat belt mechanism 20 that restrains an occupant seated on the seat 10. The seat belt mechanism 20 fixes a belt 21, a retractor 22 that winds up the belt 21, a support anchor 23 that supports the belt 21 above the retractor 22, and an end of the belt 21 that is opposite to the retractor 22. A fixed anchor 24, a tongue 25 attached to the belt 21 between the support anchor 23 and the fixed anchor 24, and a buckle 26 fixed to another anchor (not shown). The tongue 25 can be detachably attached to the buckle 26.

  The occupant seated in the seat 10 pulls out the belt 21 from the retractor 22 and attaches the tongue 25 to the buckle 26, so that his / her waist is restrained by the belt 21 </ b> A from the fixed anchor 24 to the tongue 25. You can restrain your shoulders with up to 23 belts 21B. Alternatively, by pulling out the belt 21 from the retractor 22 and attaching the tongue 25 to the buckle 26, a child seat (not shown) can be fixed to the seat 10 with the belt 21A and the belt 21B.

  As shown in FIG. 1, the seat 10 includes a cushion pad 30, a backrest member 31, and a headrest 32. A backrest member 31 is connected to the rear end portion of the cushion pad 30, and a headrest 32 is connected to the upper end portion of the backrest member 31. The cushion pad 30 is made of an elastic member such as urethane foam, and is deformed by receiving a load from an occupant or a child seat (hereinafter referred to as CRS). The cushion pad 30 is supported by a seat support portion 40 disposed below the cushion pad 30.

  FIG. 2 is a perspective view schematically showing the seat support portion 40 with the cushion pad 30 removed. As shown in FIGS. 1 and 2, the seat support portion 40 includes a support frame 42 as a substantially rectangular frame, a plurality of S-shaped springs 44 provided on the upper surface of the support frame 42, and the support frame 42. And four legs 46 extending downward. The legs 46 of the seat support portion 40 are fixed to a pair of rails 48 attached to the vehicle body, whereby the seat 10 is fixed to the vehicle body. The support frame 42, the legs 46, and the rails 48 have such rigidity that they are not deformed by the load on the occupant or CRS applied to the cushion pad 30. As the material of the support frame 42 and the legs 46, for example, metal or ceramic can be used.

  As shown in FIG. 2, the support frame 42 is formed with a rectangular opening 42A, and the S-shaped spring 44 is bridged over the opening 42A. Each S-shaped spring 44 is composed of a wire-shaped metal member that is repeatedly bent into an S-shape. The cross-sectional shape of the S-shaped spring 44 is circular, for example. The plurality of S-shaped springs 44 extend in parallel with each other in the front-rear direction, and the front end portion and the rear end portion thereof are attached to the upper surface of the support frame 42. The cushion pad 30 is placed on these S-shaped springs 44, and the cushion pad 30 is elastically supported by the plurality of S-shaped springs 44.

  As shown in FIG. 1, the airbag system 100 in this embodiment includes a displacement sensor 50 attached to a support frame 42. The displacement sensor 50 detects the vertical displacement of the S-shaped spring 44 relative to the support frame 42 (in other words, the vertical displacement of the cushion pad 30), and determines the seating state of the seat 10. 70. Although the displacement sensor 50 in this embodiment is attached to the support frame 42, it is sufficient that the position of the displacement sensor 50 is fixed relative to the support frame 42. Therefore, the displacement sensor 50 may be attached to the leg 46 or the rail 48 and the displacement sensor 50 may be fixed relatively to the support frame 42.

  FIG. 3 is a diagram schematically showing a cross section taken along line III-III in FIG. As shown in FIG. 3, a sensor support 52 that supports the displacement sensor 50 is fixed to the front member 42 </ b> B of the support frame 42. The sensor support 52 is composed of, for example, a metal plate or a resin plate. The displacement sensor 50 is fixed to the upper surface of the sensor support 52 with an adhesive or the like.

  As shown in FIG. 3, a permanent magnet 54 is attached to one S-shaped spring 44. As the permanent magnet 54, for example, a ferrite magnet, a metal magnet, a bond magnet, or the like can be used. The permanent magnet 54 is disposed so as to be positioned above the displacement sensor 50 supported by the sensor support portion 52 in the vertical direction. The permanent magnet 54 is attached to the S-shaped spring 44 by a magnet attachment 56. The magnet attachment 56 has a shape corresponding to the shape of the S-shaped spring 44 and has a spring holding portion 57 that holds the S-shaped spring 44 and a shape corresponding to the shape of the permanent magnet 54 and holds the permanent magnet 54. A magnet holding part 58 is provided.

  The displacement sensor 50 measures the magnetic field generated by the permanent magnet 54 disposed below the S-shaped spring 44, and based on the change in the magnetic field, the displacement of the permanent magnet 54, and hence the displacement of the S-shaped spring 44 and the cushion pad 30, is detected. To detect. For example, a magnetic sensor using a reed switch, a coil, a Hall element, or a magnetoresistive effect element (MR element) can be used as such a displacement sensor 50.

  FIG. 4 shows a state in which an occupant is seated on the seat 10. When an occupant sits on the seat 10, the occupant's load is applied to the cushion pad 30, whereby pressure is applied to the S-shaped spring 44 from the seating surface of the cushion pad 30. As a result, as shown in FIG. 4, both end portions of the S-shaped spring 44 are bent downward in the vertical direction, and the cushion pad 30 and the S-shaped spring 44 located in the opening 42A of the support frame 42 are moved downward. Thus, when an occupant sits on the seat 10, the cushion pad 30 and the S-shaped spring 44 are displaced downward, and the position of the permanent magnet 54 attached to the S-shaped spring 44 in the vertical direction is not seated. It becomes lower than the time position (FIG. 3). Thereby, since the permanent magnet 54 approaches the displacement sensor 50, the magnetic field measured by the displacement sensor 50 becomes strong. The displacement sensor 50 outputs the change in the magnetic field to the discrimination processing unit 70 as the displacement of the permanent magnet 54 (the displacement of the cushion pad 30 or the S-shaped spring 44).

  Thus, the displacement of the permanent magnet 54 relative to the displacement sensor 50 (the displacement of the cushion pad 30 or the S-shaped spring 44) is detected, and this displacement is output from the displacement sensor 50 to the discrimination processing unit 70. In the determination processing unit 70, the seating state in the seat 10 is determined using the displacement of the cushion pad 30 or the S-shaped spring 44 detected by the displacement sensor 50. The airbag control unit 18 controls the deployment of the airbag 12 based on the seating state determined by the determination processing unit 70.

Here, when the seat 10 is empty (case 1), when the CRS is installed on the seat 10 (in a state where it is not strongly tightened by the belt 21) (case 2), the occupant AF05 (adult female 5th percentile dummy) ) Is seated (case 3), when an occupant AM50 (adult male 50th percentile dummy) is seated on the seat 10 (case 4), and when an occupant AM95 (adult male 95th percentile dummy) is seated on the seat 10 (case 3) When the displacement of the cushion pad 30 described above was measured for each of the cases 5), the measurement results were as shown in Table 1 below.

  When deploying the airbag 12, the airbag system 100 according to the present embodiment deploys the airbag 12 relatively weakly when the occupant AF05 is seated on the seat 10, and the occupant AM50 or the occupant AM95 is seated. If so, the airbag 12 is configured to be deployed relatively strongly. That is, the discrimination processing unit 70 of the present embodiment includes (A) a seating state in which the airbag 12 does not need to be deployed, (B) a seating state in which the airbag 12 is deployed weakly, and (C) a airbag that is deployed strongly. The seating state is determined.

  (A) The seating state in which the airbag 12 does not need to be deployed corresponds to “(1) Vacant seat” and “(2) CRS” in Table 1, and (B) the seated state in which the airbag 12 is deployed weakly is “ Corresponding to (3) AF05 ”, (C) the seating state where the airbag 12 is strongly deployed corresponds to“ (4) AM50 ”and“ (5) AM95 ”. In Table 1 above, the difference in displacement between “(3) AF05” and “(1) Vacant seat” or “(2) CRS” is 4.5 mm or more. If this difference is used, “(3) It is possible to distinguish between “AF05” and “(1) Vacant seat” or “(2) CRS”. Further, since there is a displacement of 4 mm or more between “(3) AF05” and “(4) AM50” or “(5) AM95”, if this difference is used, “(3) AF05” and “(4) It can be distinguished from “AM50” or “(5) AM95”.

By the way, the above-mentioned US Federal Vehicle Safety Standard FMVSS208 defines that the CRS is fastened and fixed so that the tension of the seat belt is 134N. For this reason, when the CRS was tightened by the belt 21 with a tension of 134 N and fixed to the seat 10 (case 6), the displacement of the cushion pad 30 was measured, and the measurement results shown in Table 2 below were obtained.

  When the CRS is fastened to the seat 10 by the belt 21 with a tension of 134 N, it is not necessary to deploy the airbag 12 as in “(2) CRS”. However, as shown in Table 2, “(6 ) CRS (tension 134N) ", the displacement of the cushion pad 30 was 8 mm, the same as" (3) AF05 "in Table 1 above. Therefore, “(6) CRS (tension 134N)” and “(3) AF05” cannot be determined only by the displacement of the cushion pad 30 or the S-shaped spring 44.

Therefore, in the present embodiment, “(6) CRS (tension 134N)” and “(3) AF05” are discriminated using the pull-out length from the initial state of the belt 21 in the seat belt mechanism 20. . That is, for each case of Table 1 and Table 2, the pulling length from the initial state of the belt 21 was measured, and the measurement result was as shown in Table 3 below.

  As shown in Table 3, the pull-out length from the initial state of the belt 21 is 72 cm for “(3) AF05” and 135 cm for “(6) CRS (tension 134N)”. Then, “(3) AF05” and “(6) CRS (tension 134N)” can be discriminated. In order to detect the pull-out length of the belt 21 from the initial state, the airbag system 100 in this embodiment uses a belt pull-out sensor 60.

  FIG. 5 is a schematic diagram showing the belt pull-out sensor 60 of FIG. 1 together with the seat belt mechanism 20 and shows an initial state before the belt 21 is pulled out. FIG. 6 is a plan view schematically showing the relationship between the belt withdrawal sensor 60 and the belt 21. As shown in FIG. 5, the belt withdrawal sensor 60 of the present embodiment is provided in a belt case 28 that houses the retractor 22, and is close to the belt 21 from the reel 27 of the retractor 22 to the support anchor 23. Are arranged. As shown in FIGS. 5 and 6, the belt withdrawal sensor 60 includes a pair of element mounting portions 61 and 62 arranged with the belt 21 interposed therebetween, and a connection portion 63 that connects these element mounting portions 61 and 62. A light emitting element 64 attached to one element attaching portion 61 and a light receiving element 65 attached to the other element attaching portion 62 are provided. The element mounting portions 61 and 62 both extend parallel to the surface of the belt 21.

  As shown in FIG. 6, the light receiving element 65 is provided at a position facing the light emitting element 64 across one edge of the belt 21. The light emitting element 64 emits detection light having a predetermined wavelength. If the belt 21 does not exist between the light emitting element 64 and the light receiving element 65, the detection light emitted from the light emitting element 64 is received. The element 65 can receive and detect light. In the state shown in FIG. 5, the detection light emitted from the light emitting element 64 is blocked by one edge of the belt 21 and is not received by the light receiving element 65.

  FIG. 7 is a diagram schematically showing a part of the belt 21. As shown in FIG. 7, in this embodiment, a slit 29 is formed at a predetermined position of the belt 21. The slit 29 is formed at the edge of the belt 21 sandwiched between the light emitting element 64 and the light receiving element 65, and the portion where the slit 29 is formed is between the light emitting element 64 and the light receiving element 65 of the belt withdrawal sensor 60. When passing, the detection light emitted from the light emitting element 64 passes through the slit 29 and is received by the light receiving element 65.

  FIG. 8 is a schematic diagram showing a state in which the belt 21 is pulled out by a predetermined length from the initial state shown in FIG. As shown in FIG. 8, when the belt 21 is pulled out by a predetermined length from the initial state shown in FIG. 5, the above-described slit 29 of the belt 21 is located between the light emitting element 64 and the light receiving element 65 of the belt withdrawal sensor 60. The position of the slit 29 is set so as to be positioned. Therefore, when the belt 21 is pulled out from the initial state by a predetermined length, the slit 29 is positioned between the light emitting element 64 and the light receiving element 65, and the detection light emitted from the light emitting element 64 passes through the slit 29. Light is received by the light receiving element 65. This predetermined length is a value (for example, 90 cm) between the belt withdrawal length at “(3) AF05” and the belt withdrawal length at “(6) CRS (tension 134N)” shown in Table 3. To do. For example, the slit 29 is formed so that the slit 29 of the belt 21 is positioned between the light emitting element 64 and the light receiving element 65 of the belt withdrawal sensor 60 when the belt 21 is pulled out by 90 cm from the initial state.

As shown in FIG. 1, the displacement sensor 50 and the belt withdrawal sensor 60 described above are connected to the discrimination processing unit 70, and the output of the displacement sensor 50 and the output of the belt withdrawal sensor 60 are input to the discrimination processing unit 70. It has become. The discrimination processing unit 70 has a memory 72 as a storage device therein, in order to discriminate “(1) vacant seat” or “(2) CRS” and “(3) AF05”. The first displacement threshold d ₁ , the second displacement threshold d ₂ for discriminating between “(3) AF05” and “(4) AM50” or “(5) AM95”, and the belt 21 in the initial state And a withdrawal flag indicating whether or not a predetermined length or more has been pulled out. For example, 5 mm is stored as the first displacement threshold d _{1 and} 10 mm is stored as the second displacement threshold d ₂ .

  FIG. 9 is a flowchart showing the drawer detection process in the discrimination processing unit 70. As shown in FIG. 9, the discrimination processing unit 70 constantly monitors whether or not the detection light is detected by the light receiving element 65 of the belt pull-out sensor 60 (step S101). When the detection light is detected, the determination processing unit 70 determines whether or not the extraction flag in the memory 72 is OFF (that is, the state where the belt 21 is not extracted more than a predetermined length) (step S102). ). If the pull-out flag is OFF, the pull-out flag is rewritten to ON, and the fact that the length of the belt 21 pulled out is a predetermined length (for example, 90 cm) or more is stored in the memory 72 (step S103). . If the drawing flag is ON, the drawing flag is rewritten to OFF, and the fact that the length of the drawn belt 21 is shorter than a predetermined length (for example, 90 cm) is stored in the memory 72 (step S104). . In such a pull-out detection process, if the belt 21 is pulled out by a predetermined length (for example, 90 cm) or more, the pull-out flag is turned ON. Is turned off.

FIG. 10 is a flowchart showing the seating state determination process in the determination processing unit 70. As shown in FIG. 10, the determination processing unit 70 first determines whether or not the displacement represented by the output signal from the displacement sensor 50 is equal to or greater than the first displacement threshold d ₁ (step S201). When the displacement detected by the displacement sensor 50 is smaller than the _first displacement threshold value d ₁ (for example, 5 mm), it is a case of “(1) vacant seat” or “(2) CRS”. Then, an output signal indicating that the passenger is not seated (first seating state) is output (step S202).

On the other hand, when the displacement detected by the displacement sensor 50 is equal to or greater than the first displacement threshold d ₁ , the determination processing unit 70 determines whether the displacement is equal to or less than the _second displacement threshold d ₂ (for example, 10 mm). (Step S203). When the displacement detected by the displacement sensor 50 is larger than the _second displacement threshold d ₂ (for example, 10 mm), it is the case of “(4) AM50” or “(5) AM95”, so the discrimination processing unit 70 Outputs an output signal indicating that an occupant who strongly deploys the airbag 12 is seated (second seating state) (step S204).

If the displacement detected by the displacement sensor 50 is less than or equal to the second displacement threshold d ₂ (for example, 10 mm), it cannot be determined whether “(3) AF05” or “(6) CRS (tension 134N)”. The determination processing unit 70 determines whether or not the extraction flag stored in the memory 72 is ON (step S205). When the pull-out flag is OFF instead of ON, the belt 21 is not pulled out to a predetermined length (for example, 90 cm), and therefore it can be determined that “(3) AF05”. Therefore, in this case, the discrimination processing unit 70 outputs an output signal indicating that an occupant who should deploy the airbag 12 weakly is seated (third seating state) (step S206). When the pull-out flag is ON, the belt 21 is pulled out by a predetermined length (for example, 90 cm), so that it can be determined that “(6) CRS (tension 134N)”, and the determination processing unit 70 outputs an output signal indicating that the CRS is installed (fourth seating state) (step S207).

  As described above, in the present embodiment, the displacement sensor 50 capable of detecting the displacement in the vertical direction of the cushion pad 30 or the S-shaped spring 44 and whether the belt 21 is pulled out from the initial state by a predetermined length or more are detected. A possible belt withdrawal sensor 60, and a discrimination process for discriminating the seating state on the seat 10 based on the displacement detected by the displacement sensor 50 and the detection result of the belt withdrawal sensor 60, and outputting an output signal indicating the seating state The unit 70 constitutes a sitting state determination device that determines the sitting state of the seat 10.

  As shown in FIG. 1, the output signal from the discrimination processing unit 70 is input to the airbag control unit 18. When the impact detection sensor 16 detects an impact caused by a vehicle collision or the like, the detection signal is input to the airbag control unit 18. When the airbag control unit 18 receives the detection signal from the impact detection sensor 16, the airbag control unit 18 checks the output signal from the discrimination processing unit 70 and controls the driving of the inflators 14A and 14B. Specifically, when the output signal from the discrimination processing unit 70 is an output signal indicating the first seating state or the fourth seating state (the occupant is not seated or the CRS is installed), The airbag control unit 18 does not transmit an airbag deployment signal to any of the inflators 14A and 14B. Thereby, the airbag 12 is not deployed. When the output signal from the discrimination processing unit 70 is an output signal indicating the second seating state (the occupant to strongly deploy the airbag 12 is seated), the airbag control unit 18 includes the inflator 14A, An airbag deployment signal is transmitted to both 14B. As a result, high-pressure gas is supplied from both inflators 14A and 14B to the airbag 12, and the airbag 12 is deployed at high speed (strongly). When the output signal from the discrimination processing unit 70 is an output signal indicating the third seating state (the occupant to weakly deploy the airbag 12 is seated), the airbag control unit 18 controls the inflators 14A and 14B. An airbag deployment signal is transmitted to only one side. As a result, high-pressure gas is supplied from one of the inflators 14A and 14B to the airbag 12, and the airbag 12 is deployed at a low speed (weakly).

  As described above, according to the present embodiment, the seating state on the seat 10 can be determined by combining the displacement detected by the displacement sensor 50 and the detection result of the belt pull-out sensor 60. There is no need for expensive capacitance sensors or strain gauges. Further, unlike the conventional capacitance sensor, difficult maintenance such as maintenance and management of the membrane film and the electrode is not required. Furthermore, since the displacement detected by the displacement sensor 50 and the detection result of the belt withdrawal sensor 60 are combined, a plastic bottle containing water is not erroneously identified as an occupant.

  In recent years, there is a method of fixing the CRS to the seat without using a seat belt mechanism as in the ISOFIX standard, but even when the CRS of such a standard is fixed to the seat 10, the cushion at that time is used. Since the displacement of the pad 30 is equivalent to the case of “(2) CRS”, according to the seating state discriminating apparatus according to the present embodiment, the installation of the CRS according to the ISOFIX standard is discriminated similarly to “(2) CRS”. Can do.

  In addition, since the airbag system 100 according to the present embodiment controls the airbag 12 based on the seating state determined as described above, the airbag 12 is appropriately set according to the seating state of the seat 10. Can be deployed.

  FIG. 11 is a schematic diagram showing the belt pull-out sensor 260 in the second embodiment of the present invention together with the seat belt mechanism 20 described above, and shows an initial state before the belt 21 is pulled out. FIG. 12 is a plan view schematically showing the relationship between the belt withdrawal sensor 260 and the belt 21 at this time. As shown in FIG. 11, the belt withdrawal sensor 260 of the present embodiment is provided in a belt case 28 that houses the retractor 22, and is disposed close to the reel 27 of the retractor 22. As shown in FIGS. 11 and 12, the belt pull-out sensor 260 includes a pair of element mounting portions 261 and 262 arranged with the belt 21 wound around the reel 27 interposed therebetween, and these element mounting portions 261 and 262. A connecting portion 263 to be connected, a light emitting element 264 attached to one element attaching portion 261, and a light receiving element 265 attached to the other element attaching portion 262 are provided. The element mounting portions 261 and 262 both extend perpendicular to the surface of the belt 21.

  As shown in FIG. 12, the light receiving element 265 is provided at a position facing the light emitting element 264 with the belt 21 wound around the reel 27 interposed therebetween. Detection light having a predetermined wavelength is emitted from the light emitting element 264. If the belt 21 does not exist between the light emitting element 264 and the light receiving element 265, the detection light emitted from the light emitting element 264 is received. The element 265 can receive and detect light. In the state shown in FIG. 12, the detection light emitted from the light emitting element 264 is blocked by the belt 21 wound around the reel 27 and is not received by the light receiving element 265.

  When the belt 21 is pulled out from the reel 27, the thickness of the belt 21 wound around the reel 27 decreases. However, the light emitting element 264 and the light receiving element 265 in the present embodiment remove the belt 21 from the initial state to a predetermined value. It is arranged at a position corresponding to the thickness of the belt 21 around the reel 27 when the length (for example, 90 cm) is pulled out. That is, as shown in FIG. 13, the detection light emitted from the light emitting element 264 is received by the light receiving element 265 when the belt 21 is pulled out by a predetermined length or more from the initial state shown in FIG. ing.

  In the present embodiment, whether or not the belt 21 is pulled out by a predetermined length or more from the initial state can be determined by detection of the detection light by the light receiving element 265, so that the seating situation as in the first embodiment. There is no need to use an extraction flag for the discrimination process. That is, as shown in the flowchart of FIG. 10, in the first embodiment, it is determined whether the third seating state is output or the fourth seating state is output depending on whether the withdrawal flag is ON or OFF. In this embodiment, when the light receiving element 265 of the belt pull-out sensor 260 has not detected the detection light from the light emitting element 264, the determination processing unit 70 determines that “(3) AF05” and the air An output signal indicating that a passenger who should unfold the bag 12 is seated (third seating state) is output. On the other hand, when the light receiving element 265 of the belt pull-out sensor 260 detects the detection light from the light emitting element 264, it is determined that “(6) CRS (tension 134N)”, and no occupant is seated. Alternatively, an output signal indicating that the CRS is installed (fourth seating state) is output. Since other points are the same as those of the first embodiment described above, description thereof is omitted.

  In the embodiment described above, the example in which the permanent magnet 54 is attached to the S-shaped spring 44 has been described, but the attachment position of the permanent magnet 54 is not limited to this. For example, the permanent magnet 54 may be fixed to the lower surface of the cushion pad 30 with an adhesive or the like. Alternatively, a plate may be bridged between adjacent S-shaped springs 44, and the permanent magnet 54 may be fixed to the lower surface of the plate with an adhesive or the like.

  In the above-described embodiment, the example in which the S-shaped spring 44 is used as the spring that supports the cushion pad 30 has been described. However, the spring that supports the cushion pad 30 is not limited to the S-shaped spring. Any spring may be used as long as it can support.

  Furthermore, in the above-described embodiment, an example in which a magnetic sensor is used as the displacement sensor 50 has been described. However, the displacement sensor 50 is not limited to the magnetic sensor, and the displacement or cushion of the cushion pad 30 relative to the support frame 42 in the vertical direction. Any displacement sensor may be used as long as the displacement in the vertical direction of the S-shaped spring 44 supporting the pad 30 can be detected. For example, a laser sensor or an eddy current sensor can be used as the displacement sensor 50.

  In the above-described embodiment, when the output signal from the discrimination processing unit 70 is an output signal indicating the second seating state, the two inflators 14A and 14B are ignited and the output signal indicating the third seating state. Although one of the two inflators 14A and 14B is ignited, the present invention can be applied to the case where three or more inflators are used. In this case, the number of inflators that are ignited when the output signal from the discrimination processing unit 70 is the output signal indicating the second seating state is the inflator that is ignited when the output signal is the third seating state. It may be more than the number of. On the contrary, the present invention can be applied to a case where one inflator is used. In this case, when the output signal from the discrimination processing unit 70 is an output signal indicating the first seating state or the fourth seating state, the inflator is not ignited, and the second seating state or the third seating state is set. When the output signal indicates, the inflator is ignited.

In the above-described embodiment, the first to fourth seating states are determined using the _two displacement threshold values d ₁ and d ₂ , but the number of seating states that can be determined by increasing the number of displacement threshold values. May be increased. When the number of seating states that can be discriminated in this way is increased, three or more inflators may be provided to ignite the number of inflators corresponding to the respective seating states. For example, a third displacement threshold value may be introduced and the number of inflators may be three in order to discriminate between “(3) AM50” and “(4) AM95” described above. That is, when the displacement detected by the displacement sensor 50 is smaller than the third displacement threshold value, it is determined as “(3) AM50” and the two inflators are ignited and larger than the third displacement threshold value. In this case, it may be determined that “(4) AM95” and the three inflators may be ignited. Similarly, a displacement threshold value can be set in order to discriminate between “(3) AF05” and “(4) AM50”.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and it goes without saying that the present invention may be implemented in various forms within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 10 Seat 12 Airbag 14A, 14B Inflator 16 Impact detection sensor 18 Airbag control part 20 Seat belt mechanism 21 Belt 22 Retractor 23 Support anchor 24 Fixed anchor 25 Tongue 26 Buckle 27 Reel 28 Belt case 29 Slit 30 Cushion pad 31 Backrest member 32 Headrest 40 Seat support portion 42 Support frame 42A Opening portion 42B Front side member 44 S-shaped spring 46 Leg 48 Rail 50 Displacement sensor 52 Sensor support portion 54 Permanent magnet 56 Magnet attachment 60 Belt pull-out sensor 61, 62 Element attachment portion 63 Connection portion 64 Light emitting element 65 Light receiving element 70 Discrimination processing part 72 Memory 100 Air bag system 260 Belt pull-out sensor 261,262 Element attaching part 263 Connection part 264 Light emitting element 265 Light receiving Child

Claims (9)

A seating state discriminating device for discriminating a seating state in the seat in a vehicle provided with a seat and a seat belt mechanism for restraining an occupant seated in the seat with a belt,
A displacement sensor capable of detecting a vertical displacement of the cushion pad relative to a support frame supporting the cushion pad of the seat or a vertical displacement of a spring supporting the cushion pad;
A belt withdrawal sensor capable of detecting whether or not the belt of the seat belt mechanism is withdrawn more than a predetermined length from an initial state;
A discrimination processing unit that discriminates the seating state on the seat based on the displacement detected by the displacement sensor and the detection result of the belt pull-out sensor and outputs an output signal indicating the seating state;
A seating state discriminating apparatus comprising: The discrimination processing unit
A storage device for storing a predetermined first displacement threshold and a second displacement threshold;
Comparing the displacement detected by the displacement sensor with the first displacement threshold and the second displacement threshold;
When the detected displacement is smaller than the first displacement threshold, an output signal indicating a first seating state is output,
If the detected displacement is greater than the second displacement threshold, an output signal indicating a second seating state is output;
If the detected displacement is between the first displacement threshold and the second displacement threshold,
If the detection result of the belt pull-out sensor indicates that the belt is not pulled out beyond the predetermined length, an output signal indicating a third seating state is output;
The output signal indicating the fourth seating state is output if the detection result of the belt pull-out sensor indicates that the belt is pulled out for the predetermined length or more. The sitting state discriminating apparatus described. The output signal indicating the first seating state is a signal indicating that no occupant is seated in the seat,
The output signal indicating the second seating state is a signal indicating that an occupant is seated in the seat,
The output signal indicating the third seating state is a signal indicating that an occupant is seated in the seat. The output signal indicating the fourth seating state is that a child seat is installed in the seat. A signal indicating
The seating state discriminating apparatus according to claim 2.   The seating state discriminating apparatus according to any one of claims 1 to 3, wherein the displacement sensor is fixed relative to the support frame. A magnet fixed to the bottom surface of the cushion pad or the spring;
The displacement sensor is a magnetic sensor that detects displacement of the cushion pad or displacement of the spring based on a change in a magnetic field generated by the magnet.
The seating state discriminating apparatus according to any one of claims 1 to 4, wherein   6. The belt withdrawal sensor according to claim 1, wherein the belt withdrawal sensor detects that the belt has been withdrawn more than the predetermined length by detecting a slit formed in the belt. The sitting state discriminating apparatus described.   The belt pull-out sensor detects that the belt is pulled out more than the predetermined length by detecting a thickness of a belt wound around a reel of a retractor that winds up the belt. Item 6. The sitting state determination device according to any one of Items 1 to 5. An air bag for protecting an occupant seated in the seat;
The sitting state determination device according to any one of claims 1 to 7,
An airbag control unit that controls the operation of the airbag based on an output signal from a determination processing unit of the seating state determination device;
An air bag system comprising: An air bag for protecting an occupant seated in the seat;
A plurality of inflators for generating a gas for deploying the airbag by igniting a gas generating agent;
An airbag control unit for controlling ignition of the inflator;
A displacement sensor capable of detecting a vertical displacement of the cushion pad relative to a support frame supporting the cushion pad of the seat or a vertical displacement of a spring supporting the cushion pad;
A belt withdrawal sensor capable of detecting whether or not the belt of the seat belt mechanism is withdrawn more than a predetermined length from the initial state;
A discrimination processing unit that discriminates the seating state on the seat based on the displacement detected by the displacement sensor and the detection result of the belt pull-out sensor and outputs an output signal indicating the seating state;
With
The discrimination processing unit
A storage device for storing a predetermined first displacement threshold and a second displacement threshold;
Comparing the displacement detected by the displacement sensor with the first displacement threshold and the second displacement threshold;
When the detected displacement is smaller than the first displacement threshold, an output signal indicating a first seating state is output,
If the detected displacement is greater than the second displacement threshold, an output signal indicating a second seating state is output;
If the detected displacement is between the first displacement threshold and the second displacement threshold,
If the detection result of the belt pull-out sensor indicates that the belt is not pulled out beyond the predetermined length, an output signal indicating a third seating state is output;
If the detection result of the belt pull-out sensor indicates that the belt is pulled out more than the predetermined length, the belt pull-out sensor is configured to output an output signal indicating a fourth seating state;
The airbag control unit
When the output signal from the discrimination processing unit indicates the first seating state or the fourth seating state, none of the plurality of inflators is ignited,
When the output signal from the determination processing unit indicates the third seating state, n inflators among the plurality of inflators are ignited,
When the output signal from the discrimination processing unit indicates the second seating state, more than n inflators among the plurality of inflators are ignited.

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