JP5699816B2 - Seat occupant determination device and determination method - Google Patents

Description

  The present invention relates to a seat occupant determination device and a determination method for determining whether or not a child seat is secured to a vehicle seat.

  In recent years, in order to improve the performance of various safety devices such as seat belts and airbags installed in automobiles, there is a technique for controlling the operation of these safety devices in accordance with the weight of an occupant seated on the seat. For example, when an occupant sits on a seat and does not wear a seat belt, a warning light “seat belt not attached” is generally displayed after the seating is detected. North American legislation stipulates that airbags should be deployed in the event of an accident when an adult is seated in the passenger seat, and the child seat is tied to the driver seat with the child seat tied backwards. When facing each other, the airbag is prohibited from being deployed. This is because the impact of the airbag deployment is counterproductive for infants. In these cases, the determination of being an adult is performed using the weight of a small adult woman as a determination criterion, and the determination criterion is also set for the determination of an infant. Thus, it is extremely important in terms of safety to detect and correctly determine the weight of the passenger.

  An example of an occupant detection device that detects a load acting on a seat and determines the presence or absence of an occupant is disclosed in Patent Document 1. In this occupant detection device, load sensors are installed only at two of a large number of seat mounting portions, and the presence or absence of an occupant is determined from the sum of two obtained load values. As a result, it is said that load sensors are usually installed only at the minimum two required positions among the four seat mounting portions, and an occupant detection device that is simple and inexpensive as a whole can be provided.

  Further, Patent Document 2 discloses an example of an occupant detection device that determines whether an occupant seated on a seat is an adult or a child. The occupant detection device includes first and second load sensors that detect a seat load applied to the vicinity of the buckle of the seat belt and the opposite side, detection means that detects that a tongue plate has been inserted into the buckle, and first and first Determination means for determining that the occupant is an adult when the total load obtained from the detection value of the two-load sensor is equal to or greater than a predetermined threshold value. Further, the determination means has a history that the difference between the detection values of the first and second load sensors has increased to a predetermined value or more even before the total load is greater than or equal to a threshold value, and before and after the timing at which the tongue plate is inserted. When the detection value of the first load sensor increases, it is determined that the occupant is a child. Accordingly, it is possible to prevent erroneous determination when a child whose weight is slightly less than the threshold value is seated on the seat and the seat belt is worn by another occupant. According to the description of the embodiment, there are two each of the first and second load sensors, and the total load is obtained by detecting the load at all of the four seat mounting portions.

JP-A-9-207638 Japanese Patent No. 399740

  However, in the occupant detection device of Patent Literature 1, the number of load sensors is minimized to identify the presence or absence of occupants in order to reduce the cost and weight of the device. In the method in which the load sensor is installed only in a part of the multiple seat attachment portions, the detected load value changes depending on the seating posture of the occupant and the vehicle inclination angle.

  The occupant detection device of Patent Document 2 can accurately determine adult, child, child seat lashing, etc. by eliminating the influence of the load value that temporarily increases due to the seat belt wearing operation. Since the load sensor is installed on the entire seat mounting portion, the device is expensive and heavy.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a low-cost seat occupant determination device and a determination method that can accurately determine that a child seat is secured to a vehicle seat.

  In order to solve the above-described problem, a seat occupant determination device according to a first aspect of the present invention locks the seat belt withdrawing operation in a state where the seat belt is withdrawn from the seat belt retracting device, and winds the seat belt. A seat occupant determination device for a seat belt device having an ALR mechanism that allows only an operation in a taking direction, wherein the seat belt detects that a tongue plate of the seat belt is engaged with a buckle fixed to the rear of a vehicle seat. A mounting detection means, a front load detection means and a rear load detection means, which are arranged separately on the left and right sides of the lower side of the vehicle seat and detect a part of the load acting on the vehicle seat, respectively, and the front Add the front load value detected by the load detection means and the rear load value detected by the rear load detection means. Front / rear sum load value calculation means for calculating a rear sum load value, front / rear difference load value calculation means for calculating a difference between the rear load value and the front load value, and the seat belt attachment detection means In the determination period after the point in time when the load is detected, the variation of the front-rear sum load value over a first predetermined value within a first predetermined time and the second predetermined value within a second predetermined time of the front-rear differential load value A child seat securing determination means for determining that a child seat is secured to the vehicle seat when the above variation is detected within a predetermined period.

  In order to solve the above-described problem, a seat occupant determination device according to a second aspect of the present invention is the seat occupant determination device according to the first aspect, wherein the buckle is fixed to either the left or right side surface of the vehicle seat, and the front load detecting means and the rear load are The detection means is arranged on the left and right sides of the vehicle seat on the side where the buckle is provided.

  In order to solve the above-described problem, a seat occupant determination method according to a third aspect of the present invention locks the withdrawal of the seat belt in a state where the seat belt is withdrawn from the seat belt retractor, and winds the seat belt. A seat occupant determination method for a seat belt apparatus having an ALR mechanism that allows only an operation in a taking direction, wherein the seat belt detects that a tongue plate of the seat belt is engaged with a buckle fixed to the rear of a vehicle seat. A front load for detecting a part of the load acting on the vehicle seat by the mounting detection step and the front load detection means and the rear load detection means that are separated from each other on the left and right sides of the lower side of the vehicle seat. And a rear load detection step, a front load value detected in the front load detection step, and the rear load. A front-rear sum load value calculation step for calculating a front-rear sum load value by adding the rear load value detected in the detection step, and a front-rear difference load value calculation step for calculating a difference between the rear load value and the front load value And a variation of the front-rear sum load value that is greater than or equal to a first predetermined value within a first predetermined time and the front-rear difference within a determination period after the time when the seat belt is detected to be detected by the seat belt mounting detection step. A child seat securing determination step for determining that a child seat is secured to the vehicle seat when a change of a load value within a second predetermined time is detected within a predetermined period.

  According to the seat occupant determination device of the first aspect, the seat belt device has the ALR mechanism that enables the seat belt to move only in the winding direction. For this reason, when the child seat is fixed on the vehicle seat using the ALR mechanism, the operator needs to pull the seat belt in the winding direction of the ALR mechanism and apply tension to the seat belt.

  At this time, every time the seat belt is pulled in the winding direction, the buckle support portion provided on the vehicle seat and connected to the seat belt is pulled upward, and the center of gravity of the child seat and the vehicle seat is the diagonal direction of the vehicle seat with the buckle support portion as the center. Move to. In the vehicle seat, the load near the buckle support portion decreases, and the load decreases in accordance with the amount of movement of the center of gravity in the front and side directions of the vehicle seat with the buckle support portion as a fulcrum. The load detecting means arranged in the position respectively acquire the changed load values corresponding to the respective arrangement positions. After that, the front-rear sum load value that is the sum of the load values and the front-rear difference load value that is the difference are calculated, and the behavior of the front-rear sum load value and the front-rear difference load value within the determination period after the seat belt is attached When a predetermined condition is satisfied, it is determined that each behavior is caused by the pulling of the seat belt. When each behavior due to pulling of the front-rear sum load value and the front-rear differential load value is detected within a predetermined period, each behavior is assumed to be a result generated by one pulling operation, and this is applied to the vehicle seat. It can be determined that the child seat has been secured. In this way, when an adult is seated, at least two load detections provided in the front-rear direction of the vehicle seat can detect the fluctuation state of the center of gravity of the vehicle seat, which cannot occur even when the body weight changes, etc. The child seat can be detected at low cost and with high accuracy by means, and the child seat can be suitably determined.

  According to the seat occupant determination device of the second aspect, in the first aspect, the front load detection means and the rear load detection means are provided on the so-called inner side opposite to the door in the vehicle on the same side as the buckle. For this reason, when the seat belt is pulled to fix the child seat on the vehicle seat, the detection load value of the rear load detection means provided below and in the vicinity of the buckle support portion on the inner side is greatly reduced. Further, the load value detected by the front load detecting means also decreases according to the distance away from the rear load detecting means. As a result, the front-rear sum load value decreases, the front-rear difference load value fluctuates, and it can be determined that the child seat is secured to the vehicle seat when the decrease and fluctuation are detected within the predetermined conditions described in claim 1. . In this way, by providing the front load detection means and the rear load detection means on the inner side, which is the same side as the buckle, a sufficient amount of change in the front-rear sum load value and fluctuation in the front-rear difference load value can be obtained. As a result, the child seat can be stably determined.

  The seat occupant determination method according to claim 3 has the same effect as that of claim 1, and is low in cost by each load detection step by at least two load detection means provided in the front-rear direction of the vehicle seat, and It can detect with high precision and can suitably determine the binding of the child seat.

1 is a perspective view of a vehicle seat provided with a seat occupant determination device according to an embodiment of the present invention. It is the block diagram which showed the outline | summary of the seat occupant determination apparatus. It is a simplified diagram for demonstrating a child seat attachment state. It is a graph which shows the example of the experimental data of the front-and-rear sum load value at the time of a child seat attachment, and a front-back difference load value. It is the figure which showed the flowchart 1 which determines the back-and-forth sum load of a seat occupant determination apparatus. It is the figure which showed the flowchart 2 which determines the front-back differential load of a seat occupant determination apparatus.

  Hereinafter, a first embodiment of a seat occupant determination device 10 for a vehicle seat 1 according to the present invention will be described with reference to the drawings. In addition, the directions of “front and rear, left and right, and up and down” used in this specification are described with reference to each direction of the vehicle viewed from the occupant seated on the vehicle seat 1. In the present embodiment, the vehicle is a left steering wheel, and the child seat 5 is installed in the passenger seat.

  As shown in FIG. 1, a vehicle seat 1 for a passenger seat includes a seat cushion 11 on which an occupant is seated, and a seat back that is attached to the rear end portion of the seat cushion 11 so as to be pivotable in the front-rear direction and serves as a backrest for the occupant. 12. A headrest 13 that supports the head of the occupant is attached to the upper end of the seat back 12.

  The seat cushion 11 is formed by a seat frame 111, a pad member 112 disposed above the seat frame 111, and a skin 113 that covers the surface of the pad member 112. A pair of left and right upper rails 14 </ b> R and 14 </ b> L are attached to the lower surface of the seat frame 111. The upper rails 14R and 14L are engaged with a pair of lower rails 41R and 41L fixed on the vehicle floor 4 so as to be movable in the front-rear direction. Thus, the vehicle seat 1 is formed so as to be movable in the front-rear direction on the floor 4 and fixed at a position desired by the occupant.

  Next, the seat occupant determination device 10 will be described with reference to FIGS. 1 to 3. The seat occupant determination device 10 includes a three-point seat belt device 6 (see FIG. 3) having an ALR mechanism (not shown), a buckle switch 65 (corresponding to the seat belt wearing detection means of the present invention), and The front load sensor FL (corresponding to the forward load detecting means of the present invention), the rear load sensor RL (corresponding to the backward load detecting means of the present invention), and the controller 3 (corresponding to the child seat binding determining means of the present invention) ) And.

  As shown in FIG. 3, when the vehicle seat 1 is viewed from the front, the seat belt device 6 is attached to and detached from the shoulder strap 61, the lap strap 62, and the tongue plate 63 whose one ends are connected to each other by the tongue plate 63. A buckle 64 forming a buckle switch 65 is provided. A retractor (corresponding to the winding device of the present invention) is disposed in a pillar (not shown) located on the right side of the vehicle seat 1. The upper end of the shoulder strap 61 is connected to the retractor, and the shoulder strap 61 is pulled out against the winding force by the retractor.

  On the other hand, the other end of the lap strap 62 is connected and fixed to the vehicle floor 4 on the right side of the vehicle seat 1. The buckle 64 has a support portion 64a supported on the rear left side of the vehicle seat 1 and has an opening hole for inserting a tongue plate 63 to be described later fixed upward. The tongue plate 63 connected to the shoulder strap 61 and the lap strap 62 is inserted from the opening hole of the buckle 64 and fixed by engagement. Hereinafter, the shoulder strap 61 and the lap strap 62 are collectively referred to as a seat belt 66.

  When the tongue plate 63 and the buckle 64 of the seat belt device 6 are in the disengaged state, the buckle switch 65 is in the open state (off). When the tongue plate 63 and the buckle 64 are engaged, the buckle switch 65 is closed (ON), and the controller 3 detects that the seat belt device 6 is attached.

  The seat belt device 6 has an ALR (Automatic Locking Retractor) mechanism. The ALR mechanism is a device that locks the pull-out operation of the seat belt 66 and allows only the operation in the take-up direction of the seat belt 66 in a state where the seat belt 66 is pulled out from the retractor. The ALR mechanism is a mechanism that is mainly used when the child seat 5 is mounted on the vehicle seat 1. Since the ALR mechanism is well known, detailed description thereof is omitted.

  A pair of front and rear front load sensors FL and a rear load sensor RL are interposed between the seat frame 111 and the upper rail 14L so as to be separated from each other by a predetermined distance. As shown in FIG. 1, the front load sensor FL is provided in the front part of the front and rear center of the seat cushion 11. Further, the rear load sensor RL is provided in the rear part of the seat cushion 11 from the front and rear center.

  Each of the front load sensor FL and the rear load sensor RL is a load sensor formed by a strain gauge or the like. The load values Ff and Rf of the front load sensor FL and the rear load sensor RL are both reset to 0 when the vehicle is shipped, and are lowered downward with respect to the seat cushion 11 due to seating of an occupant on the vehicle seat 1 or placement of luggage. Detect the applied load. In the present invention, the type, model, and detection principle of the front load sensor FL and the rear load sensor RL are not limited to specific ones.

  The front load sensor FL is interposed between the front portion of the seat frame 111 and the left upper rail 14L, and detects a front load value Ff that the front left portion of the seat cushion 11 has. Similarly, the rear load sensor RL is interposed between the rear portion of the seat frame 111 and the left upper rail 14L and in the vicinity of the support portion 64a of the buckle 64 supported by the vehicle seat 1, and the seat cushion 11 The rear load value Rf that the rear left portion is responsible for is detected.

  As shown in FIG. 2, the front load sensor FL and the rear load sensor RL include sensor units 21F and 21R, and amplifier units 22F and 22R that amplify detection signals generated by the sensor units 21F and 21R, respectively. Yes. Each of the sensor portions 21F and 21R is formed by a Wheatstone bridge circuit including four strain gauges.

  A controller 3 is connected to the front load sensor FL and the rear load sensor RL. The controller 3 is necessary for determining a seating state, an A / D converter 31 that converts an analog detection signal from the front load sensor FL and the rear load sensor RL into a digital value, a calculation unit 32 that performs a calculation based on the detection signal. A storage unit 33 for storing various data such as a calculation result in the calculation unit 32 and a determination unit 34 for determining whether the child seat is secured to the vehicle seat 1 based on the calculation result of the calculation unit 32 are provided.

  The computing unit 32 includes a longitudinal sum load value computing means 35 and a longitudinal difference load value computing means 36 according to the present invention. The front-rear sum load value calculation means 35 adds the front load value Ff detected by the front load sensor FL and the rear load value Rf detected by the rear load sensor RL to calculate the front-rear sum load value (Ff + Rf). The front / rear differential load value calculating means 36 calculates a front / rear differential load value (Rf−Ff) by subtracting the front load value Ff from the rear load value Rf. The calculated front-rear sum load value (Ff + Rf) and front-rear difference load value (Rf−Ff) are stored in the storage unit 33 and then transmitted to the determination unit 34. In this embodiment, the front-rear differential load value is obtained by subtracting the front load value Ff from the rear load value Rf. Thereby, the fluctuation | variation of a back-and-forth difference load value (Rf-Ff) becomes a negative value. However, the present invention is not limited to this form, and the front-rear differential load value may be obtained by subtracting the rear load value Rf from the front load value Ff. In this case, since the fluctuation of the front / rear differential load value (Ff−Rf) is a positive value, it should be noted.

  The determination unit 34 monitors a determination period T measured from the time when the buckle switch 65 detects the wearing of the seat belt 66. Then, when the determination period T is within a predetermined period Tm (for example, 10 minutes) and the value of the front-rear sum load value (Ff + Rf) is within the predetermined value Ts, the determination of securing of the child seat 5 is executed. The predetermined value Ts is a value smaller than the front-rear sum load value (Ff + Rf) generated when a child or an adult is seated. Therefore, if the front-rear sum load value (Ff + Rf) is within the predetermined value Ts, the seating possibility of a child or an adult can be eliminated, and the child seat 5 can be accurately detected.

  Furthermore, when the determination period T is within the predetermined period Tm, the determination unit 34 determines that a decrease in the longitudinal load value (Ff + Rf) equal to or greater than the first predetermined value Fm (corresponding to the variation of the present invention) is the first predetermined value. It is confirmed that the error occurs within time trm (for example, 1S) and then returns. Further, it is confirmed that a decrease in front-to-back differential load value (Rf−Ff) equal to or greater than the second predetermined value Fn (corresponding to the variation of the present invention) occurs within a second predetermined time trn (for example, 1S) and then returns. . Then, the decrease and return of the front-rear sum load value (Ff + Rf) within the first predetermined time trm to be greater than or equal to the first predetermined value Fm and the second predetermined load value (Rf−Ff) within the second predetermined time trn. It is determined that the child seat 5 is secured to the vehicle seat 1 when a decrease or return of the value Fn or more is detected within the predetermined period Tp. In this case, the predetermined period Tp is a value determined in advance based on the result of an experiment or the like, and includes a decrease in the longitudinal load value (Ff + Rf) and a decrease in the longitudinal difference load value (Rf−Ff). It means the period of time that the interval of mutual operation overlaps, and it does not need to be completely coincident. In the above description, the first predetermined value Fm and the second predetermined value Fn are thresholds for preventing erroneous determination, and these should also be determined by a prior experiment or the like. The first predetermined value Fm and the second predetermined value Fn can be determined with reference to the fluctuation amount of the longitudinal load value (Ff + Rf) and the differential load value (Rf−Ff) when the seat belt is actually pulled. Good.

  The buckle switch 65 is connected to the controller 3. A battery 72 of the vehicle is connected to the buckle switch 65 via a DC resistor 71. When the buckle switch 65 is in the open state, no current flows through the DC resistor 71, so the controller 3 detects the positive terminal voltage (high) of the battery 72. When the buckle switch 65 is closed, a current flows through the DC resistor 71, and the controller 3 can detect a voltage drop (low) due to the DC resistor 71. Thereby, the controller 3 detects that the buckle 64 is engaged with the tongue plate 63 (described later) and the seat belt device 6 is attached.

  Further, the vehicle ignition switch 8 is connected to the controller 3. The controller 3 can detect whether the ignition switch 8 is in an on state or an off state.

  Next, based on the graphs of FIG. 3 and FIG. 4, a method of attaching the child seat 5 on the seat cushion 11 of the vehicle seat 1, and when the child seat 5 is attached, are detected by the front load sensor FL and the rear load sensor RL. The behavior of each load will be described. The graph of FIG. 4 is an example of measured data of the front and rear sum load value (Ff + Rf) and the front and rear differential load value (Rf−Ff) measured by the inventor when the child seat 5 is attached. In FIG. 4, the solid line indicates the front-rear sum load value (Ff + Rf), and the broken line indicates the front-rear differential load value (Rf−Ff). Further, the operation signal of the buckle switch 65 is shown as BS.

  As shown in FIG. 3, in the present embodiment, the child seat 5 is attached to the vehicle seat 1 in a rearward direction so that the seated infant faces the rear of the vehicle. After the child seat 5 is placed on the seat cushion 11, all (or a predetermined length) of the seat belt 66 is first pulled out from a retractor (corresponding to the winding device of the present invention) not shown. As a result, the seat belt 66 is switched to the ALR mode in which only the operation in the winding direction is allowed. In this state, a part of the lap strap 62 of the seat belt 66 is passed through a seat belt attaching portion (not shown) of the child seat 5 and the tongue plate 63 is inserted into the buckle 64 and engaged therewith. At this time, the tongue plate 63 is inserted and engaged with the buckle 64 at the rear of the vehicle seat 1 from above, so that a force pressing downward is applied to the rear of the buckle 64 and the vehicle seat 1 and the rear of the rear load sensor RL. The load value Rf increases. At the same time, the front left side of the child seat 5 is lifted and the front load value Ff detected by the front load sensor FL provided on the front left side of the vehicle seat 1 is slightly reduced. As a result, the front-rear sum load value (Ff + Rf) greatly increases and the front-rear difference load value (Rf-Ff) also increases as shown in FIG.

  Thereafter, when the engagement between the tongue plate 63 and the buckle 64 is completed, the load that presses the vehicle seat 1 downward by the tongue plate 63 is released. Therefore, after this, the front load sensor FL and the rear load sensor RL detect the load of the child seat 5 itself, so that the front-rear sum load value (Ff + Rf) decreases (see part b in FIG. 4).

  Next, the person who attaches the child seat 5 pushes the shoulder strap 61 and the lap strap 62, which are slack, in the retracting direction of the retractor and causes the retractor to wind the retracted shoulder strap 61 and the wrap strap 62. Then, after the slack of the seat belt 66 is completely removed, the shoulder strap 61 is further pulled to fix the child seat 5 on the vehicle seat 1.

  As shown by the solid line arrow in FIG. 3, when the shoulder strap 61 is pulled in the retracting direction of the retractor at this time, the buckle 64 and the buckle support portion 64a connected to the shoulder strap 61 are pulled upward, so The rear load value Rf of the provided rear load sensor RL decreases. At the same time, the seat belt 66 is pulled in the winding direction so that the lap strap 62 of the seat belt 66 is moved between the buckle 64 and the vehicle floor 4 opposite to the buckle 64 in the rear portion of the child seat 5. The child seat 5 is pressed against the upper surface of the vehicle seat 11. For this reason, the center of gravity of the child seat 5 moves rearward, the front portion of the child seat 5 rises, and the front load value Ff of the front load sensor FL decreases.

  A load obtained by combining these load values is input to the front load sensor FL and the rear load sensor RL. Specifically, the front load value Ff of the front load sensor FL decreases due to the effect of pulling up the buckle 64 and the effect of pressing the rear of the child seat 5 against the upper surface of the vehicle seat 11. Further, the rear load value Rf of the rear load sensor RL increases due to the effect that the rear of the child seat 5 is pressed against the upper surface of the vehicle seat 11, but greatly decreases as a result of taking into account the effect of raising the buckle 64 that exceeds the increase.

  As a result, the front-rear sum load value (Ff + Rf) is greatly reduced, and the front-rear difference load value (Rf-Ff) is also reduced (see FIG. 4, part c and part d). Then, the respective reduction amounts at this time both exceed the first and second predetermined values Fm and Fn, decrease (fluctuate) within the first and second predetermined time (for example, 1S), and then decrease again. If it returns to a value close to the previous front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf-Ff), the seat belt tensioning operation for securing the child seat 5 is performed even if the condition is cleared. It is determined that It should be noted that the return to the vicinity of the front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf-Ff) before the decrease is a phenomenon that occurs when the installer stops pulling the seat belt. As a result, the load due to the tension is released in a short time, and the load applied to the rear load sensor RL and the front load sensor FL is only the original weight of the child seat 5, and the load value is restored (see FIG. 4, part c and part d). .

  Such a pulling operation is performed a plurality of times for securing the actual child seat 5. Therefore, as shown in FIG. 4, a plurality of reduction and recovery behaviors of the front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf−Ff) can be seen. Then, the decrease and return behaviors of the front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf−Ff) appear within the predetermined period Tp within the predetermined determination period Tm (for example, 10 minutes) as described above. Sometimes it can be determined that each behavior has occurred as a result of one pulling operation of the seat belt. As a result, it is determined that the child seat 5 is secured to the vehicle seat 1, and the airbag is prohibited from being deployed. In the present embodiment, after the reduction exceeds the first and second predetermined values Fm and Fn, the vicinity of the front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf−Ff) before the decrease again. It is confirmed that it returns to the value. However, the present invention is not limited to this, and the return may not be confirmed. This also provides a reasonable effect. In addition, the change in the seating load in the passenger seat vehicle seat 1 mounted on the left-hand drive vehicle has been described above. However, in the case of the passenger seat vehicle seat mounted on the right-hand drive vehicle, Needless to say, the left-right relationship is reversed.

  Next, a seat occupant determination method by the seat occupant determination device 10 in the present embodiment will be described based on the flowcharts 1 and 2 in FIGS. The seat occupant determination device 10 is in a state where the ignition 8 is in an OFF state, the load on the vehicle seat 1 is not more than a predetermined value, and the buckle switch 65 (seat belt wearing detection means) of the seat belt device 6 is not turned on. The vehicle seat 1 is determined to have no occupant and stored.

  When the tongue plate 63 is inserted into the buckle 64 and the buckle switch 65 is turned on, the controller 3 is activated, and it is determined whether the adult (or child) or the child seat 5 has got on the vehicle seat 1. Start judgment. In this embodiment, it is a determination method in the case where the buckle switch 65 is turned on from such a state where there is no passenger. The ignition 8 is not limited to OFF but may be ON.

  Flowchart 1 is a determination chart for front-rear sum load value (Ff + Rf) and child seat 5 lashing, and flowchart 2 is a determination chart for front-rear differential load value (Rf-Ff). The front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf−Ff) are separated into two charts because they are processed in parallel after obtaining the front load value Ff and the rear load value Rf.

  First, the flowchart 1 shown in FIG. 5 will be described. First, in step S11 (seat belt wearing detection step) of the flowchart 1, it is determined whether or not the buckle switch 65 (seat belt wearing detecting means) of the seat belt device 6 is turned on. In the present embodiment, a main controller (not shown) of the vehicle monitors the operating state of the buckle switch 65 regardless of the operating state of the ignition switch 8. As described above, when the ignition switch 8 is in the off state, if it is detected that the buckle switch 65 is turned on, the controller 3 of the seat occupant determination device 10 is activated by the main controller, and thereafter the seat occupant determination device. 10 is performed to determine whether the child seat 5 is secured.

  If it is determined that the buckle switch 65 is turned on, the subscript i indicating the respective data numbers of the front load value Ff detected by the front load sensor FL and the rear load value Rf detected by the rear load sensor RL in step S12 is obtained. It is initialized. In step S13, measurement of the determination period T is started. In step S14, 1 is substituted into the subscript i, and the forward load value Ff (1) and the backward load value Rf (1) which are the first data in steps S15 (forward load detection step) and S16 (rear load detection step). And the acquired forward load value Ff (1) and backward load value Rf (1) are stored in the storage unit 33 of the controller 3.

  In step S17 (child seat binding determination step), it is confirmed whether or not the determination period T exceeds a predetermined value Tm set in advance. If it does not exceed Tm, the process proceeds to step S18 (front / rear sum load value calculation step), and the front / rear sum load value (Ff (i) + Rf (i)) is calculated and the process proceeds to step S19. If it exceeds the predetermined value Tm, the determination period has already ended, so the process moves to step S33, and the program ends.

  In step S19, it is determined whether the longitudinal load value (Ff (i) + Rf (i)) does not exceed a predetermined value Ts set in advance. When the predetermined value Ts is exceeded, there is a possibility that it is not the child seat 5 but the heavier, for example, an adult (or a child) on the vehicle seat 1, so that a temporary determination state is set and the program is terminated. At this time, about the adult or child made into the temporary determination state, it transfers to another program and determines. For the present invention, description of another program is omitted.

  In step S20, it is confirmed whether the longitudinal load value (Ff (i) + Rf (i)) is the maximum value. Since it is always the maximum value for the first time, the process moves to step S21, where the maximum value Fa is updated and stored in the storage unit 33 of the controller 3. In step S22, the time when the maximum value Fa is updated is stored in the storage unit 33. Thereafter, the process returns to step S14, and the processes of steps S14 to S20 are performed.

  When the maximum value Fa is not updated in step S20, the process moves to step S23. In step S23, it is confirmed whether the front-rear sum load value (Ff (i) + Rf (i)) is the minimum value Fb. If it is the first time, the minimum value is always set. In step S24, the minimum value Fb is updated and stored in the storage unit 33 of the controller 3. In step S25, the time when the minimum value Fb is updated is stored in the storage unit 33. Thereafter, the process returns to step S14, and the processes of steps S14 to S23 are performed.

  In step S23, when the minimum value Fb is not updated, the process moves to step S26. In step S26, it is confirmed whether or not the back-and-forth sum load value (Ff + Rf) has returned to the vicinity of the maximum value Fa that is the starting point of the decrease stored in step S21. If not, the process returns to step S14 again, and the process is repeated until the process returns in step S26. However, if it returns to the vicinity of Fa, it moves to step S27.

  In step S <b> 27, (Fa−Fb) indicating the amount of change in the decrease in the longitudinal load value (Ff (i) + Rf (i)) is calculated. Next, in step S28, each time when the maximum value Fa and the minimum value Fb stored in step S22 and step S25 are detected, tr1 and tr2, the change time (tr2-tr1) required from the maximum value Fa to the minimum value Fb. ) Is calculated.

  In step S29 (child seat binding determination step), it is confirmed whether or not the variation (Fa−Fb), which is the difference between the maximum value Fa and the minimum value Fb, is greater than or equal to a first predetermined amount Fm set in advance. To do. If it is equal to or greater than the first predetermined amount Fm, it is found that the load is reduced by pulling the seat belt 66, and at this time, the process proceeds to step S30. If it is less than the first predetermined amount Fm, the variation amount (Fa-Fb) is not sufficient, so the process returns to step S14 again, and processing is performed until the variation amount (Fa-Fb) becomes greater than or equal to the first predetermined amount Fm in step S29. repeat.

  In step S30 (child seat lashing determination step), the time (tr2-tr1) required to decrease the longitudinal load value (Ff + Rf) is confirmed, and the time (tr2-tr1) is less than or equal to the first predetermined time trm set in advance. If there is, the process proceeds to step S31 which is the final confirmation step. If the time (tr2-tr1) is equal to or longer than the first predetermined time trm, the process returns to step S14 and is repeatedly processed from step S14 to step S30.

  In step S31 (child seat binding determination step), the time tr4 when the decrease in the front-rear differential load value (Rf (i) -Ff (i)) calculated according to the flowchart 2 described later is completed and the before / after calculation calculated according to the flowchart 1. When the difference from the time tr2 at which the reduction of the sum load value (Ff (i) + Rf (i)) ends is calculated, and the magnitude of the difference is within a predetermined period Tp set in advance, step S32 (child seat fixing) In the binding determination step), it is determined that the child seat 5 is secured to the vehicle seat 1, and the determination result is transmitted to the airbag ECU. If the predetermined period Tp is exceeded, the process returns to step S14.

  Next, the flowchart 2 for processing the front-rear differential load value (Rf−Ff) will be described. Since the flowcharts 1 and 2 are partially the same, the description of the common parts is omitted.

  Flowchart 1 and flow chart 2 are the same from step S10 to step S17. In step S17, it is confirmed whether or not the determination period T has exceeded a predetermined period Tm. If the predetermined period Tm has not been exceeded, the process proceeds to step S40 (front / rear differential load value calculation step), and the front / rear differential load value (Rf (i) −Ff (i)) is calculated and the process proceeds to step S41. If the predetermined period Tm of the determination period T is exceeded, since the determination period has already ended, the process moves to step S53 and the program ends.

  In step S41, it is confirmed whether the front-rear differential load value (Rf (i) −Ff (i)) is the maximum value. Since it is always the maximum value for the first time, the process moves to step S42, where the maximum value Fc is updated and stored in the storage unit 33 of the controller 3. In step S43, the time when the maximum value Fc is updated is stored in the storage unit 33. Thereafter, the process returns to step S14, and the processes of steps S14 to S17, and steps S40 and S41 are repeated until the maximum value Fc is not updated.

  In step S41, when the maximum value Fc is not updated, the process moves to step S44. In step S44, it is confirmed whether the longitudinal difference load value (Rf (i) −Ff (i)) is the minimum value Fd. If it is the first time, the minimum value is always set. In step S45, the minimum value Fb is updated and stored in the storage unit 33 of the controller 3. In step S46, the time when the minimum value Fd is updated is stored in the storage unit 33. Thereafter, the process returns to step S14, and the processes of step S14 to step S17, step S40, step S41, and step S44 are repeated until the minimum value Fd is not updated.

  In step S44, when the minimum value Fd is not updated, the process moves to step S47. In step S47, it is confirmed whether or not the longitudinal difference load value (Rf (i) −Ff (i)) has returned to the vicinity of the maximum value Fc that is the starting point of the decrease stored in step S42. If not, the process returns to step S14 again, and the process is repeated until the return is confirmed in step S47. However, if it has returned to the vicinity of Fc, the process moves to step S48.

  In step S48, Fc-Fd indicating the amount of change in the decrease in the front-rear differential load value (Rf (i) -Ff (i)) is calculated. Next, in step S49, the time required for the maximum value Fc and the minimum value Fd stored in step S43 and step S46 to be detected, tr3 and tr4, and the variation time (tr4-tr3) required from the maximum value Fc to the minimum value Fd. ) Is calculated.

  In step S50 (child seat securing determination step), it is confirmed whether or not the variation (Fc−Fd), which is the difference between the maximum value Fc and the minimum value Fd, is equal to or larger than a second predetermined amount Fn set in advance. To do. If it is equal to or greater than the second predetermined amount Fn, it can be determined that the load is reduced by pulling the seat belt 66, and at this time, the process proceeds to step S51. If the amount is less than the second predetermined amount Fn, the variation amount (Fc−Fd) is not sufficient, so the process returns to step S14 again, and processing is performed in step S29 until the variation amount (Fc−Fd) becomes equal to or greater than the second predetermined amount Fn. repeat.

  In step S51 (child seat lashing determination step), the time (tr4-tr3) required to decrease the longitudinal load value (Ff + Rf) is confirmed, and the time (tr4-tr3) exceeds the preset second predetermined time trn. If so, the process returns to Step S14, and Steps S14 to S17 and Steps S40 to S51 are repeated.

  However, if the time (tr4-tr3) is less than or equal to the second predetermined time trn set in advance, the process proceeds to step S52, and the time tr4 is inserted into step S31 of the flowchart 1. As described above, in step S31 of the flowchart 1, the time tr4 (the time when the minimum value Fd was last updated) at which the decrease in the front-to-back differential load value (Rf−Ff) has ended and the front-to-back sum calculated by the flowchart 1 are used. When the difference with the time tr2 (the time when the minimum value Fb was last updated) when the decrease of the load value (Ff + Rf) is completed is calculated, and the magnitude of the difference is within a predetermined period Tp set in advance, In step S32, it is determined that the child seat 5 is secured to the vehicle seat 1, and the determination result is transmitted to the airbag ECU.

  As is apparent from the above description, in the present embodiment in which the seatbelt device 6 has the ALR mechanism, the front load sensor FL (front load detection means) and the left and right front and rear sides of the lower side of the vehicle seat 1 are provided. A rear load sensor RL (rear load detection means) is disposed in isolation. That is, the front load sensor FL (front load detection means) and the rear load sensor RL (rear load detection means) are provided on the so-called inner side opposite to the door in the vehicle on the same side as the buckle 64. The buckle support 64a provided on the vehicle seat 1 is pulled upward each time the seat belt 66 is pulled in order to secure the child seat 5, and the center of gravity of the child seat 5 and the vehicle seat 1 is centered on the buckle support 64a. Move in the diagonal direction. Thereby, each load detection means arranged before and after acquires each load value Ef, Rf after decrease (fluctuation) according to each arrangement position. Thereafter, in order to use as a stable determination index, the front-rear sum load value (Ff + Rf) obtained by adding the load values Ef, Rf and the front-rear difference load value (Rf-Ff) obtained by calculating the difference between the load values Ef, Rf are calculated. . Then, within the determination period T after the detection of the seat belt 66 being attached, the front-rear sum load value (Ff + Rf) that is less than or equal to the predetermined value Ts and decreased (varied) by the first predetermined value Fm within the first predetermined time trm. The child seat is locked to the vehicle seat 1 when the front-rear differential load value (Rf−Ff) decreased (varied) by the second predetermined value Fn within the second predetermined time trn is detected within the predetermined period Tp. It is determined that As described above, the front load sensor FL and the rear load sensor RL are provided on the inner side, which is the same side as the buckle, so that when an adult is seated, it occurs due to the pulling of the seat belt that cannot appear even if the body weight shifts or the like. A sufficient amount of decrease variation of each load value Ef, Rf can be stably acquired. As a result, it is possible to determine whether the child seat is secured with low cost and high accuracy.

  In the present invention, a pair of front and rear load sensors FL, RL provided on the seat cushion 11 may be provided at least before and after one of the left and right sides of the seat cushion 11. Therefore, a pair of front and rear load sensors FR and RR may be attached only to the right side of the seat cushion 11. In addition, seating sensors may be attached to the four corners of the seat cushion 11, respectively. Furthermore, a pair of front and rear load sensors may be provided on either side of the left and right sides of the seat cushion 11, and only one front or rear load sensor may be attached to either the front or rear of the other side.

  Here, another embodiment in which the front and rear load sensors FR and RR are arranged on the right and front sides of the seat cushion 11 described above will be briefly described (see FR and RR in FIG. 1).

  In another embodiment, a so-called outer side (door side) which is the right side of the vehicle seat 1 is one side, and a front load sensor FR (front load detection means) and a rear load sensor RR (rear load detection) are provided before and after the outer side. Means) are arranged in isolation.

  In another embodiment, as in the first embodiment, when the seat belt 66 is pulled in the retracting direction of the retractor in order to fix the child seat 5 on the vehicle seat 1, a buckle provided on the inner side of the vehicle seat 1 is used. The support part 64a is lifted. As a result, a large load is input to the front load sensor FR (front load detection means) disposed on the outer side (right side) on the diagonal line in the vehicle seat 1 with respect to the buckle support portion 64a, and the front load value Ff increases. (fluctuate. At this time, the rear load value Rf of the rear load sensor RR (rear load detection means) decreases (fluctuates) due to the effect of lifting the buckle support portion 64a.

  Further, as described in the first embodiment, when the seat belt 66 is pulled in the retracting direction of the retractor, the lap strap 62 of the seat belt 66 is simultaneously attached to the buckle 64, the buckle 64, and the rear portion of the child seat 5. The child seat 5 is pressed against the upper surface of the vehicle seat 11 between the opposite vehicle floor 4. For this reason, the center of gravity of the child seat 5 moves rearward, and the rear load value Rf of the rear load sensor RR (rear load detection means) is increased (varied), and the front portion of the child seat 5 is lifted to act as a front load. The forward load value Ff of the sensor FR is decreased (varied).

  A load obtained by combining these load values is input to the front load sensor FR and the rear load sensor RR. Thus, even when the load sensors FR and RR are arranged on the right side, there is an input value of a characteristic load that cannot be generated when an adult is seated by pulling the seat belt 66 to secure the child seat 5. can get. As a result, as in the case of the first embodiment, the front-rear sum load value (Ff + Rf) and the front-rear difference load value (Rf-Ff) are calculated, and by observing the appearance of each load value, at least two The load sensor can determine whether the child seat 5 is secured with low cost and high accuracy. The appearance of each load value varies depending on the shape of the seat, the magnitude of the force pulling the seat belt, and the like. Therefore, it is preferable to perform evaluation in advance and set each threshold value.

  Also, as a condition for starting the seating determination, instead of detecting the operation of the buckle switch 65 from OFF to ON, the vehicle seat position adjustment is completed, the vehicle door is opened and closed, and the ignition switch is turned OFF to ON. It may be a case where any one of them is detected.

DESCRIPTION OF SYMBOLS 1 ... Vehicle seat, 3 ... Child seat securing determination means (controller), 5 ... Child seat, 6 ... Seat belt apparatus, 10 ... Seat occupant determination apparatus, 11 ... Seat cushion, 31 ... A / D converter, 32 ... calculation unit, 33 ... storage unit, 34 ... determination unit, 35 ... front-rear sum load value calculation means, 36 ... front-rear differential load value Calculation means, 61 ... shoulder strap, 62 ... lap strap, 63 ... tongue plate, 64 ... buckle, 65 ... seat belt wearing detection means (buckle switch), Ff ... forward load Value, FL, FR: forward load detection means (front load sensor), Rf: rear load value, RL: rear load detection means (rear load sensor), RR: rear load detection means (rear) Load center Sa).

Claims (3)

A seat occupant determination device for a seat belt device having an ALR mechanism that locks the seat belt withdrawing operation and permits only the operation in the seat belt winding direction in a state where the seat belt is withdrawn from the seat belt winding device by a predetermined amount. Because
Seat belt wearing detection means for detecting that the tongue plate of the seat belt is engaged with a buckle fixed to the rear of the vehicle seat;
A front load detection means and a rear load detection means, which are arranged separately on the front and rear sides of the left and right sides of the vehicle seat, respectively detecting a part of the load acting on the vehicle seat;
A front-rear sum load value calculating means for calculating a front-rear sum load value by adding the front load value detected by the front load detecting means and the rear load value detected by the rear load detecting means;
Front-rear differential load value calculating means for calculating a difference between the rear load value and the front load value;
Within a determination period after the time when the seat belt wearing is detected by the seat belt wearing detection means,
When a fluctuation of the front-rear sum load value over a first predetermined value within a first predetermined time and a fluctuation of the front-back difference load value over a second predetermined value within a second predetermined time are detected within a predetermined period. A child seat lash determination means for determining that a child seat is lashed to the vehicle seat;
A seat occupant determination device. In claim 1,
The buckle is fixed to either the left or right side of the vehicle seat;
The front load detection means and the rear load detection means are seat occupant determination devices arranged on the left and right sides of the vehicle seat on the side where the buckle is provided. A seat occupant determination method for a seat belt apparatus having an ALR mechanism that locks the withdrawal of the seat belt in a state in which the seat belt is pulled out from the seat belt retractor and allows only the operation in the seat belt retracting direction. Because
A seat belt wearing detection step for detecting that the tongue plate of the seat belt is engaged with a buckle fixed to the rear of the vehicle seat;
A front load and a rear load detection step of detecting a part of the load acting on the vehicle seat by the front load detection means and the rear load detection means arranged separately on the left and right sides of the lower side of the vehicle seat, respectively. When,
A front-rear sum load value calculation step of calculating a front-rear sum load value by adding the front load value detected in the front load detection step and the rear load value detected in the rear load detection step;
A front-rear differential load value calculation step for calculating a difference between the rear load value and the front load value;
Within a determination period after the time when the seat belt wearing is detected by the seat belt wearing detection step,
When a fluctuation of the front-rear sum load value over a first predetermined value within a first predetermined time and a fluctuation of the front-back difference load value over a second predetermined value within a second predetermined time are detected within a predetermined period. A child seat securing determination step for determining that a child seat is secured to the vehicle seat;
A seat occupant determination method comprising:

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