JP5834543B2 - 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 the weight of the occupant and correctly determine the state on the seat.

  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 the many 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.

  Patent Document 2 discloses an example of a seating determination device that detects a load applied to a seat and determines whether or not a child seat is attached. In this seating determination device, load sensors are installed at two left and right positions (especially at the rear two positions) of a large number of seat mounting portions, and the load variation characteristically generated when the child seat is mounted is summed up of two load values. Whether or not the child seat is attached is determined from the difference. Thereby, it is said that load sensors are installed only at the two left and right positions, which are necessary at a minimum, and a simple and inexpensive seating determination device can be provided.

  Furthermore, Patent Document 3 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. Even if the total load is greater than or equal to the threshold value, 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, and before and after the timing at which the tongue plate is inserted. When the detection value of the 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 JP 2011-16396 A 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. As described above, in the method in which the load sensor is installed only in a part of the seat attachment portions at many places, the detected load value changes depending on the seating posture of the occupant and the vehicle inclination angle.

  Further, in the seating determination device of Patent Document 2, the change in the load in the left-right direction is captured and used to determine whether or not the child seat is mounted. Load variation is not used.

  Furthermore, the occupant detection device disclosed in Patent Document 3 can accurately determine the binding of adults, children, and child seats 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 is connected to a seat belt retractor provided at one end above a vehicle seat, and the other end is connected to the one side. A strap fixed to the lower side and a strap that is movably connected to an intermediate portion of the strap, divides the strap into a shoulder strap and a lap strap, and a buckle provided on the lower side of the vehicle seat. A seat occupant determination device for a seat belt device, comprising: a removable tongue plate; and a locking clip that couples the shoulder strap and the lap strap on the one side to fix the lap strap at a predetermined length. Seat belt wearing detection means for detecting that the tongue plate is engaged with the buckle The vehicle seat isolated disposed around at least one side of the one side and the other side in the lower side of the front load detecting means and the vehicle seat to detect a portion of the load acting on the front of the vehicle seat A rear load detection means for detecting a part of the load acting on the rear of the vehicle, and a front-rear sum by adding the front load value detected by the front load detection means and the rear load value detected by the rear load detection means The tongue is calculated by the front and rear sum load value calculation means for calculating the load value, the front and rear difference load value calculation means for calculating the front and rear difference load value by subtracting the front load value from the rear load value, and the seat belt wearing detection means. A second threshold value smaller than the first threshold value after the front-rear sum load value has risen above the first threshold value within a first predetermined time from the detection time point when the engagement of the plate with the buckle is detected. The load difference value before and after the predetermined drop width exceeds the maximum value of the difference load value detected in the second predetermined time shorter than the first predetermined time starting from the detection time point. A child seat lash determination means for determining that a child seat is lashed to the vehicle seat when it is detected that the vehicle has been lowered.

  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 a rear side portion on the other side of the vehicle seat, and The load detection means is disposed on the side where the buckle is fixed.

  In order to solve the above-described problem, in a seat occupant determination device according to a third aspect, in the first aspect, the buckle is fixed to a vehicle floor on a rear portion on the other side of the vehicle seat.

In order to solve the above-described problem, a seat occupant determination method according to a fourth aspect is configured such that one end is connected to a seat belt retractor provided on one side of the vehicle seat and the other end is on the one side. A strap fixed to the lower side and a strap that is movably connected to an intermediate portion of the strap, divides the strap into a shoulder strap and a lap strap, and a buckle provided on the lower side of the vehicle seat. A seat occupant determination method for a seat belt apparatus, comprising: a removable tongue plate; and a locking clip that joins the shoulder strap and the lap strap on the one side to fix the lap strap at a predetermined length. Seat belt attachment detection step for detecting that the tongue plate is engaged with the buckle. And flop, the isolated disposed around at least one side of the one side and the other side in the lower side of the vehicle seat, front load detecting means and the you find some of the load acting on the front of the vehicle seat A front load detecting step and a rear load detecting step for detecting a part of the load acting on the front and rear of the vehicle seat by a rear load detecting means for detecting a part of the load acting on the rear of the vehicle seat; A front-rear sum load value calculating step of calculating a front-rear sum load value by adding the front load value detected in the load detection step and the rear load value detected in the rear load detection step; The tongue plate is calculated by a front / rear differential load value calculating step for calculating a front / rear differential load value by subtracting a load value, and the seat belt wearing detection step. Within a first predetermined time from the detection time point when the engagement of the belt with the buckle is detected, the front-rear sum load value has risen above the first threshold and then dropped below a second threshold smaller than the first threshold. And the front-rear differential load value has fallen beyond a predetermined fall width from the maximum value of the front-rear differential load value detected within a second predetermined time shorter than the first predetermined time, starting from the detection time point. A child seat securing determination step for determining that a child seat is secured to the vehicle seat when detected.
In order to solve the above-described problem, in the seat occupant determination device according to claim 5, when the child seat lash determination unit further confirms that the front-rear sum load value is in a stable state, It is determined that the child seat has been secured.

  In the seat occupant determination device according to the first aspect, the child seat is secured by a locking clip that has been widely used for securing the child seat. In such a securing method, the child seat installer puts weight on the rear portion of the child seat to bend the vehicle seat, engages the tongue plate with the buckle in this state, and the child seat is loosened on the seating surface of the vehicle seat. Tighten up not to be tied up.

  At this time, when the installer moves the weight to the rear of the vehicle seat in order to bend the vehicle seat, the rear load value detected by the rear load detection means arranged behind the vehicle seat increases as the weight moves. . Further, in the front part of the vehicle seat, a rotational moment is generated with the rear part where the load is increased as a fulcrum, so that the lift occurs, and the front load value detected by the front load detection means arranged in front of the same side as the rear load detection means. Will decrease. In the present invention, a front-rear sum load value (front load value + rear load value) and a front / rear differential load value (rear load value-front load value) are calculated based on the detected front load value and rear load value. After that, when the lashing is completed and the installer starts to descend from the child seat, the front-rear sum load value and the front-rear differential load value decrease, and eventually only the load generated by the child seat and child seat lashing is detected. It reaches a state of being stably given to the means.

  Then, after the fluctuating sum load value fluctuating above the first threshold value is decreased to a second threshold value that is smaller than the first threshold value, the front and back difference load value is detected to be engaged with the tongue plate on the buckle. Each of the two characteristic phenomena of descending beyond a predetermined descending width from the maximum value detected within the second predetermined time from the detection time point appears within the first predetermined time starting from the detection time point. The variation of the load value is generated by the child seat lashing operation, and it is determined that the child seat is lashed to the vehicle seat. In this way, the characteristic load fluctuation state of the vehicle seat that occurs only by the child seat lashing operation, which cannot appear even when the adult is seated, in the front-rear direction on one side of the vehicle seat. The at least two load detecting means provided can be detected at low cost and with high accuracy, and the child seat can be suitably determined for lashing.

  According to the seat occupant determination device of the second aspect, in the first aspect, the buckle is provided on the rear side surface on the other side of the vehicle seat, and the front load detection means and the rear load detection means are on the same side as the buckle. In the so-called inner side opposite to the door. As described above, since the rear load detection means is provided below and in the vicinity of the buckle support portion, the tongue plate is pressed against the buckle while the weight is applied to the rear portion of the child seat for lashing. The load value that increases can be acquired with certainty. Further, since the front load detecting means is provided on the same other side as the rear load detecting means, the front load of the vehicle seat which has been lifted and reduced by pressing the tongue plate against the buckle can be detected well. By these, it is possible to acquire a sufficient amount of fluctuations in the front-rear sum load value and the front-rear difference load value, and to determine whether the child seat is secured with high accuracy.

  According to the seat occupant determination device of the third aspect, in the first aspect, the buckle is provided on the vehicle floor below the side surface on the other side of the vehicle seat. For this reason, the impact load input from the seat belt at the time of a vehicle collision or the like is input to the vehicle floor and is not input to the vehicle seat. Thereby, the strength of the vehicle seat can be reduced and the cost can be reduced. In addition, since the tensile load from the seat belt is not input to the rear load detection means, the design strength of the rear load detection means and the mounting portion of the rear load detection means can be reduced, and a simple structure can be achieved. Reduction can be achieved.

  According to the seat occupant determination method of the fourth aspect, the same effect as in the first aspect is achieved, and the load is reduced by each load detection step by at least two load detection means provided in the front-rear direction of the vehicle seat. In addition, the child seat can be detected with high accuracy and can be suitably determined.

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 explaining the child seat attachment state according to the first embodiment. It is a block diagram of the tongue plate which concerns on this embodiment. It is an attachment state figure of the locking clip which fixes a shoulder strap and a lap strap. 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 is the main program of a seat occupant determination apparatus. FIG. 3 is a diagram showing a flowchart 2 which is a subroutine A used in the flowchart 1. FIG. 3 is a diagram showing a flowchart 3 which is a subroutine B used in the flowchart 1. FIG. 6 is a diagram showing a flowchart 4 which is a subroutine C used in the flowchart 1. It is a simplified diagram for explaining a child seat attachment state according to another embodiment.

  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 to be movable in the front-rear direction on the vehicle floor 4 and to be fixed at a position desired by the occupant.

  Next, the seat occupant determination device 10 will be described with reference to FIGS. The seat occupant determination device 10 includes a three-point seat belt device 6 (see FIG. 3), and includes a buckle switch 65 (corresponding to the seat belt wearing detection means of the present invention) and a front load sensor FL (of the present invention). And a rear load sensor RL (corresponding to the rear load detecting means of the present invention) and a controller 3 (corresponding to the child seat securing determining means of the present invention).

  The seat belt device 6 includes a winding device having an ELR (Emergency Locking Retractor) mechanism (not shown), and as shown in FIG. 3 in a state in which the vehicle seat 1 is viewed from the front, a strap 66, a tongue plate 63, a buckle 64, and A locking clip 67 is provided. As shown in FIGS. 3 to 5, the strap 66 includes a shoulder strap 61 and a lap strap 62, and each strap 61, 62 is divided by a tongue plate 63 movably connected to an intermediate portion of the strap 66. . Here, the intermediate portion refers to a portion between one end and the other end which are both ends of the strap 66.

  The ELR mechanism normally restrains the occupant to the vehicle seat 1 by locking the shoulder strap 61 (or the strap 66), which can be wound and pulled out, in the pulling direction in an emergency such as a collision. This mechanism ensures the safety of passengers. The structure and the like of the ELR mechanism are well known and will not be described in detail because they are not related to the operation in the present invention.

  A retractor (not shown) constituting a take-up device for the seat belt device 6 is arranged in a pillar (not shown) located on the right side of the vehicle seat 1 (corresponding to one side of the present invention). The retractor is disposed below the pillar. A retractor strap (not shown) connected to the retractor and connected to the retractor so as to be rewound and retractable extends to the upper side of the pillar. The retractor strap is inserted through a slit hole (not shown) penetrating the pillar and is connected to the end of the shoulder strap 61 which is one end of the strap 66 in the vehicle interior. The end of the lap strap 62, which is the other end of the strap 66, is fixed to the lower vehicle floor 4 behind the right side of the vehicle seat 1 (corresponding to one side of the present invention). In the present embodiment, the retractor disposed in the pillar and the retractor strap connected to the retractor are collectively referred to as a winding device.

  The shoulder strap 61 constituting the strap 66 is a part for protecting the seated person by restraining the upper body of the seated person who is seated mainly with the seat belt device 6 in the worn state in an emergency such as a vehicle collision. . As described above, the end of the shoulder strap 61 (one end of the strap 66) is connected to the retractor strap of the winding device. As a result, the shoulder strap 61 (strap 66) can be retracted by the retractor and pulled out against the retracting force of the retractor at normal times.

  The lap strap 62 constituting the seat belt 66 is a part for restraining the seated person by restraining the waist part of the seated person who is seated mainly with the seat belt device 6 in the worn state in an emergency such as a vehicle collision. The other end of the strap 66, which is the end of the lap strap 62, is connected and fixed to the vehicle floor 4 below the right side (corresponding to one side of the present invention) of the vehicle seat 1 as described above. When the other end of the strap 66 is connected to the vehicle floor 4, a retractor having an automatic winding function for detecting a vehicle collision and winding the strap 66 in advance by the rotational force of the motor and applying tension to the strap 66 is strapped. The other end of 66 and the vehicle floor 4 may be interposed and fixed. This also provides the same effect. Similarly, the retractor connected to one end of the strap 66 may be a retractor having an automatic winding function.

  As shown in FIG. 4, the tongue plate 63 has a tongue portion 63a and a support portion 63b. The tongue part 63a is made of metal having conductivity, and the support part 63b is formed by covering a part of the tongue part 63a with resin. The support portion 63b has a slit-like insertion hole 63c, and the strap 66 is inserted into the insertion hole 63c, whereby the tongue plate 63 is connected to the intermediate portion of the strap 66 so as to be movable in the extending direction of the strap 66. . Then, the tongue plate 63 distributes the shoulder strap 61 and the lap strap 62 to predetermined lengths by moving the position of the tongue plate 63 in the extending direction of the strap 66 and divides it. For example, when a person seated on the vehicle seat 1 or a child seat to be placed is relatively large, a necessary length of the lap strap 62 for pressing and fixing the person or the child seat on the seating surface of the vehicle seat 1 Is relatively long. For this reason, the tongue plate 63 moves in the direction of the shoulder strap 61 and makes the length of the lap strap 62 longer according to the object, and then engages with the detachable buckle 64. At this time, the shoulder strap 61 is pulled out from the retractor by the length of the lap strap 62, and the length of the shoulder strap 61 is thereby maintained. Therefore, when it is necessary to extend the length of the shoulder strap 61, the shoulder strap 61 may be further pulled out from the retractor. Conversely, when shortening the length of the lap strap 62 in accordance with the object to be worn, the tongue plate 63 is moved in the direction of the lap strap 62 to shorten the length of the lap strap 62 and then engaged with the buckle 64. Thus, the shoulder strap 61 and the lap strap 62 are divided by using the position of the tongue plate 63 after the movement as a boundary point.

  The buckle 64 is fixed to a fixing portion 64a on the lower side surface on the left side (corresponding to the other side of the present invention) with respect to the vehicle seat 1, and an opening hole for inserting the tongue plate 63 opens upward. . The tongue plate 63 is inserted into the opening hole of the buckle 64 from above and engaged and fixed. When the tongue plate 63 of the seat belt device 6 and the buckle 64 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 locking clip 67 shown in FIG. 5 is a so-called H clip. The locking clip 67 fixes the length of the lap strap 62 formed to a predetermined length by the movement of the tongue plate 63. Specifically, first, the shoulder strap 61 on the front and rear of the tongue plate 63 and the surfaces on the same side of the lap strap 62 are bundled facing each other with the length of the lap strap 62 set to a desired length. Then, the straps 61 and 62 are passed through the slit-like space of the locking clip 67 as shown in FIG. 5 as shown in FIG. As a result, relative movement between the locking clip 67 and the straps 61 and 62 is prevented, and the length of the lap strap 62 is fixed. At this time, the tongue plate 63 is positioned at an intermediate point of the bag-shaped strap formed between the fixing point on the shoulder strap 61 side fixed by the locking clip 67 and the fixing point on the lap strap 62 side.

  Thus, when the tongue plate 63 is engaged with the buckle 64, half of the bag-shaped strap forms part of the lap strap 62, and the other half forms part of the shoulder strap 61. And the length of the lap strap 62 is fixed to a desired length. At this time, the fixing position of the locking clip 67 is preferably in the vicinity of the side surface opposite to the buckle 64 (that is, the vehicle door side) in the left-right direction, which is one side of the vehicle seat 1. This ensures good mounting workability of the locking clip 67 and visibility for checking the mounting state.

  A pair of front and rear front load sensors FL and a rear load sensor RL on the left side (the other side) of the vehicle seat 1 are interposed between the seat frame 111 and the upper rail 14L, 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. The present invention does not limit the types, types, and detection principles of the front load sensor FL and the rear load sensor RL to specific ones.

  The front load sensor FL is interposed between a front portion of the seat frame 111 and a left upper rail 14L (corresponding to the other side of the present invention), and detects a front load value Ff that the front left portion of the seat cushion 11 has. To do. Similarly, the rear load sensor RL is fixed to a fixing portion 64a between the rear portion of the seat frame 111 and the upper rail 14L on the left side (corresponding to the other side of the present invention) and on the rear side surface of the vehicle seat 1. A rear load value Rf that is interposed in the vicinity of the buckle 64 and that is handled by the rear left side portion of the seat cushion 11 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. . 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. As a result, the differential load value (Rf−Ff) becomes a positive 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 negative value, the determination may be made while paying attention to that point.

  The determination unit 34 executes a determination process for securing the child seat 5 from the time point when the buckle switch 65 detects the seat belt 66 being worn. The determination unit 34 determines whether the child seat 5 is satisfied when the following two conditions are satisfied within a first predetermined time T1 (for example, 5S) shown in FIG. 6 measured from the time when the seat belt 66 is detected. It is determined that the vehicle seat 1 is secured. FIG. 6 is an example of actual measurement data of the front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf−Ff) when the child seat 5 is attached. In FIG. 6, the solid line indicates the longitudinal load value (Ff + Rf), and the broken line indicates the longitudinal difference load value (Rf−Ff). Further, the operation signal of the buckle switch 65 is shown as BS. However, the data shown in FIG. 6 is merely an example, and is data including a case where a front load value Ff (not shown) becomes a negative value. However, the front load value Ff and the rear load value Rf vary depending on various factors such as the shape of the vehicle seat that is actually applied, the mounting method, the mounting position, and how the weight of the mounter is applied when the child seat 5 is secured. . For this reason, it will be described that the forward load value Ff may not be a negative value during the securing operation of the child seat 5 by the installer other than the data shown in FIG. 6 of the present embodiment.

  The first condition is that the front-rear sum load value (Ff + Rf) first rises above the first threshold CL1, and then falls below the second threshold CL2, which is smaller than the first threshold CL1 (see FIG. 6). That is, when the child seat 5 is secured, as shown in part a of FIG. 6, the installer first puts weight on the rear portion of the vehicle seat 1 in order to engage the tongue plate 63 with the buckle 64. Then, by inserting the tongue 63a of the tongue plate 63 into the opening of the buckle 64, the buckle switch 65 is turned on. At this time, when the load on the rear portion of the vehicle seat 1 increases, a rotational moment is generated in the vehicle seat 1 with the rear portion of the vehicle seat 1 as a fulcrum. As a result, the front portion of the vehicle seat 1 is lifted, and the forward load value Ff is changed from a positive value to a negative value on the way to decrease. In this embodiment, it has been confirmed by experiments that the amount of decrease in the forward load value Ff at this time is smaller than the amount of increase in the rear load value Rf. As a result, the front / rear sum load value (Ff + Rf) increases in calculation when the installer puts the weight on the rear portion of the vehicle seat 1, and the increase amount of the front / rear sum load value (Ff + Rf) at this time is the weight of the installer. It is confirmed by the first threshold value CL1 obtained and set by evaluation in advance.

  Thereafter, the tongue plate 63 is further pressed toward the buckle 64 and completely engaged. As a result, the rear load value Rf at the rear portion of the vehicle seat 1 increases. At this time, the front load value Ff decreases beyond the decrease in the rear load value Rf, and the total longitudinal load value (Ff + Rf) slightly decreases. (Refer to FIG. 6, part b).

  Thereafter, when the child seat 5 is completely secured and the installer moves away from the child seat 5, the increased rear load value Rf and the decreased front load value Ff given by the weight of the installer are released. As a result, the front-rear sum load value (Ff + Rf) decreases with a predetermined inclination, and eventually only the weight related to the child seat 5 is stably applied to the front load sensor FL and the rear load sensor RL (FIG. 6). , Part c).

  At this time, the behavior of the front-rear sum load value (Ff + Rf) in the middle of the decrease shows a slightly gradual decrease in calculation in the region where the front load value Ff is negative (see FIG. 6, part d). After the load value Ff shifts to a positive region, it shows a characteristic that decreases rapidly (see part e in FIG. 6). That is, in the region where the forward load value Ff is negative, the forward / reverse load value (Ff + Rf) is calculated so that the negative forward load that contributed to become a small value is released, and the forward / rearward load value is calculated together with the backward load. Exit. As a result, the front-rear load value (Ff + Rf) decreases relatively slowly in the initial period of decrease because the negative front load value Ff increases toward positive. Then, when the forward load value Ff turns to a positive value that contributed to increase the front-rear sum load value (Ff + Rf) from the middle, the rate of decrease of the front-rear sum load value (Ff + Rf) increases from the beginning. Decreases with a large inclination, and eventually, only the weights of the child seat 5 and the vehicle seat 1 are stably applied to the front load sensor FL and the rear load sensor RL (see part c in FIG. 6). Then, it is confirmed by the second threshold value CL2 whether or not the reduced longitudinal load value (Ff + Rf) has decreased to near the weight of the child seat 5 and the vehicle seat 1. The first threshold value CL1 varies depending on the assumed weight of the installer, the shape and strength of the vehicle seat 1, the mounting position of the front load sensor FL and the rear load sensor RL, the mounting position of the buckle 64, and the like. It is preferable that an appropriate value is determined by experiments or the like. The second threshold CL2 may be determined from the weight of the vehicle seat 1 and the child seat 5.

  The second condition is that, in the longitudinal load difference value (Rf−Ff), the descending width D is predetermined from the maximum value Fmax detected within the second predetermined time T2, which is shorter than the first predetermined time T1, starting from the detection time point. Is descending over a descending width Dm (see FIG. 6).

  When the child seat 5 is secured, the rear load value Rf and the front load value Ff change as described above under the first condition. At this time, when the front is lifted and the forward load value Ff is changed to a negative value, the front-rear differential load value (Rf−Ff) is greatly increased in calculation, and the maximum value Fmax is detected (see FIG. 6, part f). The maximum value Fmax is detected when the installer rides on the child seat 5 and puts his weight on the child seat 5 and engages the tongue plate 63 while pressing the tongue plate 63 in the buckle 64 direction. Therefore, in the present embodiment, the detection time of the maximum value Fmax is a second predetermined time T2 (for example, the time from when the buckle switch 65 is turned on until the tongue plate 63 is completely pushed into the buckle 64 to complete the engagement. 1 second). And the magnitude | size of the fall width D which is the reduction | decrease amount of the back-and-forth difference load value (Rf-Ff) from the maximum value Fmax generate | occur | produced when an installer leaves | separates from the child seat 5 is confirmed by predetermined fall width Dm. At this time, the second predetermined time T2, the maximum value Fmax, and the descending width Dm are appropriately determined by a prior experiment or the like.

  At this time, the behavior of the front-rear differential load value (Rf−Ff) that decreases from the maximum value Fmax shows a characteristic in which the forward load value Ff decreases with a large inclination throughout the negative region and the positive region described above. (See FIG. 6, part g). That is, when the installer starts the operation of descending from the child seat 5, the negative front load that has contributed to increase the magnitude of the front-rear differential load value (Rf−Ff) until then is released, and the rear Along with the load, the difference between the longitudinal load values (Rf−Ff) is lost. As a result, at the initial stage of the decreasing behavior, the front-rear differential load value (Rf−Ff) decreases with a large slope in terms of calculation as the negative forward load value Ff increases. And even if the forward load value Ff changes to a positive value from the middle, as the positive value increases in the calculation, it contributes to reducing the front-rear differential load value (Rf−Ff), so it decreases with a large slope as in the initial stage. . As a result, the above-described reduction characteristic of the front and rear sum load value (Ff + Rf) (see FIG. 6, d and e) and the reduction characteristic of the front and rear differential load value (Rf−Ff) (see FIG. 6 and g part) are inclined. It shows different characteristic characteristics. When each behavior of the front-rear sum load value (Ff + Rf) and the front-rear difference load value (Rf−Ff) within the first predetermined time T1 (for example, 5S) satisfies the above-described conditions, each load value Ff , Rf variation is determined to be caused by the child seat securing operation.

  As described above, in the present embodiment, the maximum value Fmax of the front-rear differential load value (Rf−Ff) is larger than the maximum value of the front-rear sum load value (Ff + Rf). However, in the case where the forward load value Ff does not become a negative value, the maximum value Fmax of the front-rear differential load value (Rf−Ff) is smaller than the maximum value of the front-rear sum load value (Ff + Rf). Nor.

  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 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, a method for attaching the child seat 5 on the seat cushion 11 of the vehicle seat 1 will be described with reference to FIG. 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. Therefore, the child seat 5 is first placed on the seat cushion 11. Then, as described above, the straps 61 and 62 are bundled and joined by the locking clip 67 so that the length of the lap strap 62 becomes a length suitable for attaching the child seat 5 (see FIG. 5). At this time, the length of the lap strap 62 suitable for attaching the child seat 5 means that the bundled straps 61 and 62 are inserted into the strap insertion holes 5a provided in the rear portion of the child seat 5 without applying a load to the child seat 5. When the tongue plate 63 is to be inserted into the buckle 64, it is preferable that the tongue plate 63 does not reach the buckle 64 slightly. However, as to how far the tongue plate 63 and the buckle 64 need to be separated, the degree of attachment is evaluated after the child seat 5 is actually secured, and if the attachment is loose, the separation distance is further increased. Adjust it.

  Next, as described above, the straps 61 and 62 bundled by the locking clip 67 are inserted into the strap insertion holes 5a provided in the rear portion of the child seat 5, and the tongue plate 63 is protruded to the left side (the other side) of the vehicle seat 1. deep. At this time, the locking clip 67 is disposed in the vicinity of the right side (one side) of the vehicle seat 1 (see FIG. 3).

  In such a state, the installer gets on the child seat 5 and shifts the center of gravity so that the weight is applied to the rear portions of the child seat 5 and the vehicle seat 1 (see a part of FIG. 6). As a result, the rear portion of the pad member 112 included in the seat cushion 11 of the vehicle seat 1 is bent and the child seat 5 sinks into the pad member 112. The length of the fixed lap strap 62 becomes an appropriate length, and the tongue plate 63 can be inserted into the opening hole of the buckle 64 fixed to the fixing portion 64a on the rear side surface of the vehicle seat 1.

  Then, the tongue plate 63 is inserted into the buckle 64 from above, and when the tongue portion 63a of the tongue plate 63 contacts the conduction portion in the buckle 64, the buckle switch 65 is turned on. Thereafter, when the tongue plate 63 is further pressed into the buckle 64, the tongue plate 63 is completely engaged with the buckle 64. As a result, a downward pressing force is applied to the rear of the buckle 64 and the vehicle seat 1 to which the buckle 64 is fixed, and the rear load value Rf detected by the rear load sensor RL further increases. At the same time, the front left side of the child seat 5 is further lifted, and the front load value Ff detected by the front load sensor FL decreases. As a result, as shown in FIG. 6, part f, the front-rear differential load value (Rf−Ff) further increases and the maximum value Fmax is detected.

  Thereafter, after the engagement between the tongue plate 63 and the buckle 64 is completed, when the installer descends from the child seat 5, the load applied to the front load sensor FL and the rear load sensor RL is released. As a result, the front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf-Ff) are greatly reduced by the different inclinations as described above, as shown in parts d, e, and g of FIG. 1 and only the weight of the child seat 5 are detected. At this time, the child seat 5 is fixed well with the bending force of the pad member 112 being restored by a predetermined amount and the restoring force of the pad member 112 and the pressing force of the lap strap 62 are balanced.

  And each behavior (a-g part of FIG. 6) of the front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf-Ff) satisfies the above-mentioned conditions within the first predetermined time T1 (for example, 5S). When satisfied, it is determined that the variation in each load value is caused by the lashing operation of the child seat 5.

  In the above, the variation in the seating load in the passenger seat vehicle seat 1 mounted on the left-hand drive vehicle has been described. 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. That is, in the case of a vehicle seat for a passenger seat of a right-hand drive vehicle, one side corresponds to the left side of the vehicle seat and the other side corresponds to the right side of the vehicle seat.

  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 to 4 of FIGS. 7 to 10. 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.

  First, the flowchart 1 of FIG. 7 which is a main program for seat occupant determination according to the present invention will be described. The flowchart 1 finally determines whether the child seat 5 is secured based on the results of the subroutines A to C of the flowcharts 2 to 4. Specifically, when the program of the flowchart 1 is started, a subroutine A of the flowchart 2 shown in FIG. 8 which will be described in detail later is executed (step S1). Subroutine A is a program for detecting ON of buckle switch 65 and sequentially acquiring front and rear load values Ff and Rf.

  Next, the subroutine B of the flowchart 3 shown in FIG. 9, which will be described in detail later, is executed (step S2). Subroutine B is for determining whether or not the longitudinal load value (Ff + Rf) satisfies a predetermined condition 1 described later. If condition 1 is not satisfied, it is determined that the child seat 5 is not secured on the vehicle seat 1 (step S6). If condition 1 is satisfied, the process moves to step S3.

  In step S3, subroutine C of flowchart 4 shown in FIG. Subroutine C determines whether or not the differential load value (Rf−Ff) satisfies a predetermined condition 2 described later. If the condition 2 is not satisfied, it is determined that the child seat 5 is not secured on the vehicle seat 1 (step S6). If condition 2 is satisfied, the process moves to step S4.

  In step S4 (child seat binding determination step), it is determined whether or not an elapsed time T since turning on the buckle switch 65 is smaller than a first predetermined time T1 set for the child seat binding determination. If the first predetermined time T1 is exceeded, the determination time has ended, so the process moves to step S5, where it is determined that the child seat 5 is secured on the vehicle seat 1, and the program ends. If the first predetermined time T1 has not been exceeded, the process proceeds to step S15, which will be described later in the flowchart 1, and the process is repeated until the first predetermined time T1 is reached.

  Next, the subroutines A to C in the flowcharts 2 to 4 will be described. First, the flowchart 2 (subroutine A) shown in FIG. 8 will be described. First, in step S9 (seat belt wearing detection step) in the flowchart 2, 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 S10 is obtained. It is initialized. In step S11, measurement of the elapsed time T from when the buckle switch 65 is turned on is started. In steps S12 to S14, flags 1 to 3 are set to 0. In step S15, 1 is added to the subscript i, and the forward load value Ff (1) and the backward load value Rf (1), which are the first data in steps S16 (forward load detection step) and S17 (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. Then, the process moves to the flowchart 3 (subroutine B) in FIG. The acquired forward load value Ff (i) and backward load value Rf (i) are used in flowcharts 3 and 4 hereinafter.

  Next, the flowchart 3 (subroutine B) shown in FIG. 9 will be described. In subroutine B, it is determined whether or not a predetermined condition 1 of the longitudinal load value (Ff + Rf) that appears characteristically when the child seat 5 is secured to the vehicle seat 1 is satisfied. Here, the condition 1 is that the back-and-forth sum load value (Ff + Rf) rises to the first threshold value CL1 or more after the buckle switch 65 is turned on, then falls to the second threshold value CL2 that is smaller than the first threshold value CL1, and then changes stably. It is to be.

  In step S18 (sub-routine B load value calculation step) of the flowchart 3 (subroutine B), the front-rear sum load value (Ff (i) + Rf (i)) is calculated and the process proceeds to step S19. In step S19, it is confirmed whether flag1 is 1. Initially, in step S12 of the flowchart 2, since flag1 is set to 0, the process proceeds to step S20 (child seat lashing determination step) with N. If flag1 is 1, the process moves to step S22.

  In step S20, it is determined whether or not the front-rear sum load value (Ff (i) + Rf (i)) exceeds the first threshold value CL1 of Condition 1 described above. If it does not exceed the first threshold value CL1, the process moves to step S25. In step S25, it is determined whether or not the elapsed time T since turning on the buckle switch 65 is smaller than the first predetermined time T1. If the first predetermined time T1 is exceeded, the determination time is over, so the process moves to step S26, and the processing is ended as Condition 1 is not satisfied. If the first predetermined time T1 is not exceeded, the process returns to step S15 of the flowchart 2. Then, the processing is continued until the front-rear sum load value (Ff (i) + Rf (i)) exceeds YES at the first threshold value CL1 at step S20 in flowchart 3 or exceeds the first predetermined time T1 at step S25.

  If the first threshold value CL1 is exceeded in step S20, it is determined that the wearer is putting weight on the child seat 5 in order to attach the child seat 5, and the process moves to step S21 in Y to set 1 to flag1.

  In step S22 (child seat binding determination step), it is determined whether the front-rear sum load value (Ff (i) + Rf (i)) is smaller than the second threshold value CL2 described above. If the front-rear sum load value (Ff (i) + Rf (i)) is still greater than or equal to the second threshold value CL2, the process after moving to step S25 and turning on the buckle switch 65 is the same as NO in step S20. It is determined whether the time T is smaller than the first predetermined time T1. If the first predetermined time T1 is exceeded, the determination time is over, so the process moves to step S26, and the processing is ended as Condition 1 is not satisfied. If the first predetermined time T1 is not exceeded, the process returns to step S15 in the flowchart 2 to add 1 to i. Then, the processing is continued until the front-rear sum load value (Ff (i) + Rf (i)) becomes smaller than the second threshold value CL2 in step S22 in the flowchart 3 or becomes YES or exceeds the first predetermined time T1 in step S25. . At this time, when step S19 is processed again after passing through step S21 (1 ← flag), since flag is 1, the process moves from step S19 to step S22.

  And if it becomes smaller than 2nd threshold value CL2 in step S22, since it will be understood that the installation person has completed the attachment of the child seat 5 and got off (separated) from the child seat 5, it moves to step S23.

  In step S23, it is confirmed whether the longitudinal load value (Ff (i) + Rf (i)) is in a stable state. Any confirmation method may be used. For example, the differential value between the longitudinal load value (Ff (i) + Rf (i)) and (Ff (i + 1) + Rf (i + 1)) is confirmed, and when the differential value is smaller than a predetermined value, What is necessary is just to determine that there exists. Note that step S23 is not necessary, and a corresponding effect can be obtained without it.

  If the stable state cannot be confirmed in step S23, the process moves to step S25 in N as in step S22. If the elapsed time T is longer than the first predetermined time T1, the process moves to step S26, and the processing is terminated as Condition 1 is not satisfied. If the first predetermined time T1 has not been exceeded, the process returns to step S15 in the flowchart 2 to add 1 to i and continue the process. Then, in step S23 of the flowchart 3, the stability of the front-rear sum load value (Ff (i) + Rf (i)) can be confirmed, and the process is continued until YES is determined or the first predetermined time T1 is exceeded in step S25. As in the case of step S22 described above, in step S19, since flag is 1, the process moves from step S19 to step S22. If the stability of the front-rear sum load value (Ff (i) + Rf (i)) can be confirmed in step S23, the process proceeds to step S24, and the condition 1 is satisfied, and the process proceeds to subroutine C.

  Next, the flowchart 4 (subroutine C) shown in FIG. 10 will be described. In the subroutine C, it is determined whether or not a predetermined condition 2 of the longitudinal difference load value (Rf−Ff) that appears characteristically when the child seat 5 is secured to the vehicle seat 1 is satisfied. Here, the condition 2 is that the descending width D exceeds the predetermined descending width Dm from the maximum value Fmax detected within the second predetermined time T2 shorter than the first predetermined time T1, starting from the detection time of the buckle switch 65. It is to descend (see FIG. 6).

  In step S31 (front / rear differential load value calculation step), the front / rear differential load value (Rf (i) −Ff (i)) is calculated, and the process proceeds to step S32. In step S32, it is confirmed whether flag2 is 1. Initially, in step S13, flag2 is set to 0, so that the process moves to step S33 (child seat lashing determination step) with N. If flag2 is 1, the process moves to step S36.

  In step S33 (child seat tying determination step), it is determined whether or not an elapsed time T after turning on the buckle switch 65 is smaller than a second predetermined time T2. The second predetermined time T2 is a time for searching for the maximum value Fmax value of the differential load value (Rf (i) −Ff (i)). If the elapsed time T does not exceed the second predetermined time T2, the process moves to step S34 (child seat binding determination step).

  In step S34, the maximum value Fmax of the longitudinal difference load value (Rf (i) −Ff (i)) measured within the second predetermined time T2 and stored in the storage unit 33 is searched and stored. As a result, between the rear load value Rf (i) in which the load increases according to the weight of the installer and the front load value Ff (i) that decreases due to the lift generated in conjunction with the increase in the rear load value Rf (i). The biggest difference can be found. That is, it is possible to accurately detect the state in which the installer applies the largest load to the rear of the vehicle seat 1, thereby detecting the mounting operation with high accuracy.

  The process moves from step S34 to step S15 in the flowchart 2 and the process is repeated until the elapsed time T becomes larger than the second predetermined time T2 in step S33. When the elapsed time T becomes longer than the second predetermined time T2, the process moves to step S35 and 1 is set in flag2.

  Next, in step S36, it is confirmed whether flag3 is 1. At first, since flag3 is set to 0 in step S14, the process moves to step S37 (child seat lashing determination step) with N. If flag3 is 1, the process moves to step S39.

  In step S37 (child seat securing determination step), the latest front-rear differential load value (Rf (i) -Ff) is calculated from the maximum value Fmax of the front-rear differential load value (Rf (i) -Ff (i)) searched and stored in step S34. It is determined whether or not a difference obtained by subtracting (i)) (hereinafter referred to as a descending width D) exceeds a predetermined descending width Dm. If the descending width D does not exceed the predetermined descending width Dm, the process moves to step S41.

  In step S41, if the elapsed time T is smaller than the first predetermined time T1, the process proceeds to step S15 of the flowchart 2. In step S37, the descending width Dm is exceeded, or in step S41, the elapsed time T is greater than the first predetermined time T1. The process continues until the value is increased and the process proceeds to step S42 and the condition 2 is not satisfied and the process ends. Since flag2 is 1 in step S32 of the intermediate process, the process moves to step S36 all at once.

  In step S37, if the descending width D exceeds the predetermined descending width Dm, the process moves to step S38 and 1 is set in flag3. Then, the process moves to step S39, where it is confirmed that flag3 is already standing and that the latest descending width D exceeds the predetermined descending width Dm. Here, in step S37, it is confirmed whether or not the descending width D once descending beyond the predetermined descending width Dm has risen again. If the lowering width D is smaller than the predetermined lowering width Dm, the process moves to step S42 in N, and condition 2 is not satisfied. If the predetermined descending width Dm is exceeded, the process proceeds to step S40, the condition 2 is satisfied, the process is terminated, and the process proceeds to step S4 in the flowchart 1.

  In step S4 of the flowchart 1, it is determined whether or not the elapsed time T is smaller than the first predetermined time T1, and if the first predetermined time T1 has elapsed, it is determined that the child seat 5 is secured to the vehicle seat 1. . If the first predetermined time T1 has not been exceeded, the process returns to step S15 in the flowchart 2 to continue the processing.

  As described above, in the flowchart 1, the subroutines A to C are sequentially executed. The establishment of condition 1 is confirmed in subroutine B (step S2), and the establishment of condition 2 is confirmed in subroutine C (step S3). Then, in step S4, it is confirmed whether or not the conditions 1 and 2 in steps S2 and S3 are continued for the first predetermined time T1. During the first predetermined time T1, when it is confirmed that continuation is established, it is determined that the child seat 5 is secured to the vehicle seat 1, and a determination result is transmitted to the airbag ECU. If any of the conditions 1 and 2 is not satisfied in step S2 and step S3, the process moves to step S6, and it is determined that the child seat 5 is not on the vehicle seat 1. Since there is a possibility that the vehicle seat 1 is heavier, for example, an adult (or a child), the temporary determination state is set and the program is terminated. At this time, an adult or a child in the provisional determination state may be determined by moving to another program. For the present invention, description of another program is omitted.

  As is clear from the above description, according to the seat occupant determination device 10 according to the present embodiment, when the child seat 5 is secured using the locking clip 67, the vehicle seat 1 is first applied by the installer applying the weight. The rear load increases. At this time, a rotational moment is generated in the front portion of the vehicle seat 1 so that the rear portion with the increased load is lifted around the fulcrum, and the load on the front portion is reduced. Thereafter, when the lashing is completed and the installer moves away from the child seat 5, the positive or negative load applied to each part supporting the vehicle seat 1 is released, and only the weight of the child seat 5 and the vehicle seat is stable. To be granted.

  Then, within the first predetermined time T1 from the detection time point when the engagement of the tongue plate 63 with the buckle 64 is detected, the fluctuations in the front-rear sum load value (Ff + Rf) and the front-rear differential load value (Rf-Ff) satisfy predetermined conditions. When it is satisfied, it is determined that the variation of each load value is caused by the child seat securing operation. As described above, when an adult is seated, the fluctuation state of the load of the vehicle seat 1 that can only occur due to the movement of the child seat 5 and that cannot occur even when the body weight is moved is indicated in the front-rear direction on the other side of the vehicle seat 1. The at least two forward load sensors FL (front load detection means) and the rear load sensor RL (rear load detection means) provided can be detected at low cost and with high precision, and the child seat 5 can be suitably determined to be secured. it can.

  In addition, according to the seat occupant determination device 10 according to the present embodiment, the buckle 64 is provided on the other side (left side) of the rear side of the vehicle seat 1, and the front load sensor FL (front load detection means) and the rear load sensor are provided. RL (rear load detection means) is provided on the so-called inner side opposite to the door in the vehicle on the same side as the buckle 64. For this reason, when the installer presses and engages the tongue plate 63 with the buckle 64 in the state where the weight is applied to the rear portion of the child seat 5 for tying the child seat 5, it is below the fixing portion 64a to which the buckle 64 is fixed. In addition, the detected load value of the rear load sensor RL (rear load detecting means) provided in the vicinity is further increased by the amount of pressing and engaging the tongue plate 63 and is reliably detected. Further, since the front load sensor FL (front load detection means) is disposed on the other side (left side), which is the same as the rear load sensor RL, the reduced load corresponding to the lift of the front portion is detected with high accuracy. As a result, the front-rear sum load value (Ff + Rf) and the front-rear difference load value (Rf-Ff) vary more greatly. Therefore, a sufficient amount of front-rear sum load value (Ff + Rf) and front-rear difference load value (Rf-Ff) Fluctuation can be acquired, and the child seat can be accurately determined.

  In the present invention, a pair of the front and rear load sensors FL, RL provided below the vehicle seat 1 may be provided at least before and after one of the left and right sides of the vehicle seat 1. Therefore, unlike the first embodiment, a pair of front and rear front and rear load sensors FR and RR (see FIGS. 1 to 3) may be attached only to the right side (one side) of the vehicle seat 1. In addition, seating sensors may be attached to the four corners of the vehicle seat 1, respectively. Further, a pair of front and rear load sensors may be provided on the left and right sides of the vehicle seat 1 and on the front and rear sides of the vehicle seat 1, and only one front or rear load sensor may be attached to either the front or rear of the other side or the one side. Even in these cases, the same result is obtained although the degree of each load value obtained is different. The appearance of each load value varies depending on the shape of the vehicle seat 1, the magnitude of the force applied to the strap 66, and the like. Therefore, each threshold value (first and second threshold values) for performing an evaluation in advance and making a determination is used. CL1, CL2, first and second predetermined times T1, T2, etc.) are preferably set appropriately.

  Next, another embodiment will be described. In the first embodiment, the buckle 64 is fixed to the rear side portion on the other side (left side) of the vehicle seat 1. However, as another embodiment, a buckle 64 may be provided on the vehicle floor 4 below the side surface on the other side of the vehicle seat 1 as shown in FIG. For this reason, the impact load input from the strap 66 at the time of a vehicle collision or the like is input to the vehicle floor 4 and is not input to the vehicle seat 1. Thereby, the intensity | strength of the vehicle seat 1 can be reduced and cost reduction can be aimed at. Further, since the tensile load from the strap 66 is not input to the rear load sensor RL (rear load detection means), the design strength of the rear load sensor RL itself and the mounting portion (upper rail 14 etc.) of the rear load sensor RL is also improved. Since it can be reduced, a simple structure can be achieved and cost reduction can be achieved.

  However, in another embodiment, even if the installer presses and engages the tongue plate 63 with the buckle 64 for securing the child seat 5, the load value detected by the rear load sensor RL (rear load detection means) is detected. There is no increase. However, even in this case, the determination may be made in the same manner as in the first embodiment. Further, in another embodiment, the fixing support of the buckle 64 is not limited to the vehicle floor 4. As another support mode, a fixing portion of the buckle 64 may be provided on the pair of left and right lower rails 41R and 41L fixed to the vehicle floor 4 or on the upper rails 14R and 14L engaged on the lower rails 41R and 41L.

  As a condition for starting the determination, instead of detecting the operation of the buckle switch 65 from OFF to ON, any of completion of vehicle seat position adjustment, opening and closing operation of the vehicle door, and operation of the ignition switch from OFF to ON It may be when there is such a detection.

  In the first embodiment, the seat belt device 6 is a seat belt device having an ELR mechanism. However, the seat belt device 6 is not limited to this aspect, and has an ALR (Automatic Locking Retractor) mechanism. May be. The ALR mechanism is a device that switches the mode to ALR when the seat belt 66 is pulled out of the retractor by a predetermined amount, locks the pull-out operation of the seat belt 66, and allows only the operation of the seat belt 66 in the winding direction. The ALR mechanism is a mechanism that is mainly used when the child seat 5 is mounted on the vehicle seat 1. In the present invention, the ALR mechanism is not used for securing the child seat 5, but the child seat 5 may have this mechanism.

  Further, in the present embodiment, the child seat 5 is determined using actual numerical values such as the first and second threshold values CL1 and CL2 and the descending width Dm for the determination of the binding of the child seat 5. However, the present invention is not limited to this, and determination may be made by converting a numerical value into a ratio (change rate). In other words, for example, when the installer completes the attachment of the child seat 5 and descends from the child seat 5, the reduction amount of each load may be determined based on the reduction rate compared to before the reduction. This also provides the same effect.

DESCRIPTION OF SYMBOLS 1 ... Vehicle seat, 3 ... Child seat securing determination means (controller), 4 ... Vehicle floor, 5 ... Child seat, 6 ... Seat belt apparatus, 10 ... Seat occupant determination apparatus, DESCRIPTION OF SYMBOLS 11 ... Seat cushion, 31 ... A / D converter, 32 ... Operation part, 33 ... Memory | storage part, 34 ... Determination part, 35 ... Front-rear sum load value calculation means, 36・ ・ ・ Front-to-back differential load value calculation means, 61 ・ ・ ・ Shoulder strap, 62 ・ ・ ・ Lap strap, 63 ・ ・ ・ Tang plate, 64 ・ ・ ・ Buckle, 65 ・ ・ ・ Seat belt wearing detection means (buckle switch) , 66 ... strap, 67 ... rocking clip, Ff ... forward load value, FL ... forward load detection means (front load sensor), Rf ... rear load value, RL ... rear load Detecting means (rear load sensor).

Claims (5)

One end is connected to a seat belt retractor provided on the upper side of the vehicle seat, and the other end is movably connected to an intermediate portion of the strap, and a strap fixed to the lower side of the one side. A tongue plate that divides the strap into a shoulder strap and a lap strap and that can be attached to and detached from a buckle provided on the lower side of the vehicle seat, and the shoulder strap and the wrap strap on the one side. A seat occupant determination device for a seat belt device comprising: a locking clip that is coupled to fix the lap strap at a predetermined length;
Seat belt wearing detection means for detecting that the tongue plate is engaged with the buckle;
The vehicle seat isolated disposed around at least one side of the one side and the other side in the lower, the front load detecting means and the vehicle seat to detect a portion of the load acting on the front of the vehicle seat A rear load detecting means for detecting a part of the load acting on the rear;
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;
A front / rear difference load value calculating means for calculating a front / rear difference load value by subtracting the front load value from the rear load value;
Within a first predetermined time from a detection time when the engagement of the tongue plate to the buckle is detected by the seat belt wearing detection means,
Detected within a second predetermined time shorter than the first predetermined time, starting from the detection time point, that the sum of the longitudinal load values has risen above the first threshold value and then decreased to a second threshold value smaller than the first threshold value. A child seat securing determination means for determining that the child seat is secured to the vehicle seat when it is detected that the longitudinal difference load value has fallen beyond a predetermined descending width from a maximum value of the front / rear differential load value When,
A seat occupant determination device. In claim 1,
The buckle is fixed to the rear side of the other side of the vehicle seat;
The front load detection means and the rear load detection means are seat occupant determination devices arranged on the side where the buckle is fixed. In claim 1,
The buckle is a seat occupant determination device fixed to a rear vehicle floor on the other side of the vehicle seat. One end is connected to a seat belt retractor provided on the upper side of the vehicle seat, and the other end is movably connected to an intermediate portion of the strap, and a strap fixed to the lower side of the one side. A tongue plate that divides the strap into a shoulder strap and a lap strap and that can be attached to and detached from a buckle provided on the lower side of the vehicle seat, and the shoulder strap and the wrap strap on the one side. A locking occupant for locking the lap strap with a predetermined length, and a seat occupant determination method for a seat belt device comprising:
A seat belt wearing detection step for detecting that the tongue plate is engaged with the buckle;
The vehicle seat isolated disposed around at least one side of the one side and the other side in the lower, the front load detecting means and the vehicle seat you find some of the load acting on the front of the vehicle seat A front load detecting step and a rear load detecting step of detecting a part of the load acting on the front and the rear of the vehicle seat by a rear load detecting means for detecting a part of the load acting on the rear, respectively;
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 difference load value calculation step of calculating a front / rear difference load value by subtracting the front load value from the rear load value;
Within a first predetermined time from the detection time point when the engagement of the tongue plate to the buckle is detected by the seat belt wearing detection step,
Detected within a second predetermined time shorter than the first predetermined time, starting from the detection time point, that the sum of the longitudinal load values has risen above the first threshold value and then decreased to a second threshold value smaller than the first threshold value. A child seat securing determination step for determining that the child seat is secured to the vehicle seat when it is detected that the longitudinal difference load value has fallen beyond a predetermined descending width from a maximum value of the front / rear difference load value When,
A seat occupant determination method comprising: In any one of Claims 1 thru | or 3,
The child seat lash determination unit is a seat occupant determination device that determines that the child seat is locked to the vehicle seat when it is further confirmed that the front-rear sum load value is in a stable state.

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