Buckle, judgment system and judgment method

Abstract

To determine whether an object on a seat is an occupant or a child seat, accurately.SOLUTION: A buckle comprises: a body part which can be coupled to a tongue fitted to a seat belt of a vehicle; a buckle switch which detects presence of coupling between the tongue and the body part; a sensor for detecting tension change of the seat belt; a detecting part for, on the basis of tension change detected by the sensor, detecting a vital sign which is breathing or a pulse; and a determining part for, on the basis of a detection state of the buckle switch, and a detection state of the vital sign, determining whether an object on a seat of the vehicle is a child seat or an occupant.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a buckle, a determination system, and a determination method. [Background technology]

[0002] Conventionally, there is known a technology that determines that a child seat is attached to a seat when it detects that the tongue plate attached to the seat belt is inserted into the buckle and the seat belt is fastened with a predetermined tension or more (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-95060 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the child car seat is not attached with a tension equal to or greater than a predetermined tension, there is a risk of the child car seat being misjudged.

[0005] The present disclosure provides a buckle, a determination system, and a determination method that can determine with high accuracy whether an object on a seat is a passenger or a child seat. [Means for solving the problem]

[0006] The present disclosure provides: a main body portion connectable to a tongue attached to a seat belt of a vehicle; a buckle switch that detects whether the tongue and the main body are connected; a sensor for detecting a change in tension of the seat belt; a detection unit that detects a vital sign, such as respiration or pulse, based on the change in tension detected by the sensor; The buckle includes a determination unit that determines whether an object on the vehicle seat is a passenger or a child seat based on the detection state of the buckle switch and the detection state of the vital signs.

[0007] The present disclosure also provides: a buckle that can be coupled to a tongue attached to a seat belt of a vehicle; a determination device that determines an object on a seat of the vehicle, The buckle is a buckle switch that detects whether the tongue and the buckle are connected; a sensor for detecting a change in tension of the seat belt; a detection unit that detects a vital sign, such as respiration or pulse, based on the change in tension detected by the sensor; The determination device provides a determination system that determines whether the object is a passenger or a child seat based on the detection state of the buckle switch and the detection state of the vital signs.

[0008] The present disclosure also provides: Detects whether the tongue attached to the vehicle's seat belt is connected to the buckle, Detecting a change in tension of the seat belt; Detecting a vital sign, such as respiration or pulse, based on the detected tension change; A determination method is provided for determining whether an object on the vehicle seat is a passenger or a child seat based on the connection detection state and the vital sign detection state. [Effects of the Invention]

[0009] According to the technology of the present disclosure, it is possible to determine with high accuracy whether an object on a seat is an occupant or a child seat. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a seat belt device. [Figure 2]1 is a block diagram showing an example of the configuration of a buckle according to a first embodiment. FIG. [Figure 3] 10 is a table showing a first example of a determination method performed by a determination unit. [Figure 4] 10 is a flowchart showing a first example of a determination method performed by a determination unit. [Figure 5] 10 is a table showing a second example of a determination method performed by the determination unit. [Figure 6] 10 is a flowchart showing a second example of a determination method performed by the determination unit. [Figure 7] 10 is a table showing a third example of a determination method performed by the determination unit. [Figure 8] 10 is a flowchart showing a third example of a determination method performed by the determination unit. [Figure 9] 10 is a table showing a fourth example of a determination method performed by the determination unit. [Figure 10] 10 is a flowchart showing a fourth example of a determination method performed by the determination unit. [Figure 11] 1 is a front view of the appearance of a buckle according to an embodiment of the present invention. [Figure 12] 2 is a cross-sectional view of the buckle according to the present embodiment taken along the line AA. FIG. [Figure 13] FIG. 2 is an exploded perspective view of the buckle according to the embodiment. [Figure 14] FIG. 2 is an exploded perspective view of some components of the buckle according to the present embodiment. [Figure 15] FIG. 4 is a cross-sectional view illustrating a mechanism for detecting tension of a seat belt. [Figure 16] FIG. 4 is a cross-sectional view illustrating a mechanism for detecting tension of a seat belt. [Figure 17] FIG. 4 is a cross-sectional view illustrating a mechanism for detecting tension of a seat belt. [Figure 18] FIG. 10 is a block diagram showing an example of the configuration of a buckle according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment will be described below.

[0012] 1 is a diagram showing an example of the configuration of a seat belt device. The seat belt device 1 is an example of an in-vehicle system installed in a vehicle. The seat belt device 1 includes, for example, a seat belt 4, a retractor 3, a shoulder anchor 6, a tongue 7, and a buckle 8.

[0013] The seat belt 4 is an example of a seat belt that restrains an occupant 11 seated in a vehicle seat 2, and is a belt-shaped member that is retracted and retracted around a retractor 3. The seat belt is also called a webbing. A belt anchor 5 at the tip of the seat belt 4 is fixed to the seat 2 or to a vehicle body in the vicinity of the seat 2.

[0014] The retractor 3 is an example of a retracting device that enables retracting or unreeling of the seat belt 4, and when deceleration equal to or greater than a predetermined value is applied to the vehicle, such as during a vehicle collision, the retractor 3 restricts the seat belt 4 from being unreeled from the retractor 3. The retractor 3 is fixed to the seat 2 or to the vehicle body near the seat 2.

[0015] The shoulder anchor 6 is an example of a belt insertion tool through which the seat belt 4 is inserted, and is a member that guides the seat belt 4 pulled out from the retractor 3 toward the shoulder of the occupant 11. The shoulder anchor 6 is fixed to the seat 2 or to a vehicle body in the vicinity of the seat 2.

[0016] The tongue 7 is an example of a belt insertion tool through which the seat belt 4 is inserted, and is a component slidably attached to the seat belt 4 guided by the shoulder anchor 6.

[0017] The buckle 8 is a component to which the tongue 7 is detachably connected, and is fixed to the seat 2 or a part of the vehicle body in the vicinity of the seat 2, for example.

[0018] The buckle 8 has a main body 8a and a stay 8b. The main body 8a is a portion to which the tongue 7 is detachably connected. The stay 8b is an example of a support member that supports the main body 8a of the buckle 8. The stay 8b is fixed to the seat 2 or to a portion of the vehicle body near the seat 2.

[0019] When the tongue 7 is connected to the buckle 8, the portion of the seat belt 4 between the shoulder anchor 6 and the tongue 7 is a shoulder belt portion 9 that restrains the chest and shoulders of the occupant 11. When the tongue 7 is connected to the buckle 8, the portion of the seat belt 4 between the belt anchor 5 and the tongue 7 is a lap belt portion 10 that restrains the waist of the occupant 11.

[0020] Fig. 2 is a block diagram showing an example of the configuration of a buckle according to the first embodiment. In the first embodiment, the buckle 8 shown in Fig. 2 includes a buckle switch 13, a sensor 20, a detection unit 30, a determination unit 70, and an output unit 80.

[0021] The buckle switch 13 is an example of a connection detection means that detects connection between the tongue 7 and the main body 8a of the buckle 8. The buckle switch 13 detects whether the tongue 7 and the main body 8a are connected, thereby detecting whether the seat belt 4 is fastened. The buckle switch 13 detects a state in which the tongue 7 and the main body 8a are not connected as a state in which the seat belt 4 is not fastened (seat belt 4 not fastened state). On the other hand, the buckle switch 13 detects a state in which the tongue 7 and the main body 8a are connected as a state in which the seat belt 4 is fastened (seat belt 4 fastened state).

[0022] The sensor 20 detects the tension (hereinafter also referred to as "tension F") acting on the seat belt 4, and outputs an output signal that changes in accordance with the detected tension F. When the seat belt 4 is fastened by the occupant 11, the movement of the chest and abdomen of the occupant 11 caused by the body movement and breathing of the occupant 11 is transmitted to the seat belt 4, thereby changing the tension F of the seat belt 4. The change in the tension F of the seat belt 4 is transmitted to the tongue 7, and then transmitted to the buckle 8 via the tongue 7. The sensor 20 may be provided on the main body 8a of the buckle 8, or on the stay 8b of the buckle 8.

[0023] The sensor 20 detects, for example, deformation or displacement caused by a change in tension F of the seat belt 4 as tension F of the seat belt 4. For example, the sensor 20 may be a strain sensor that detects a change in load input from the seat belt 4 to the buckle 8 via the tongue 7, or a capacitance sensor that detects a change in capacitance caused by a change in tension F of the seat belt 4. Furthermore, when the tension F of the seat belt 4 changes, the buckle 8 itself, which is connected to the seat belt 4 via the tongue 7, is displaced. Therefore, the sensor 20 may be a device that detects the displacement of the buckle 8 itself as a change in tension F of the seat belt 4. For example, a non-contact sensor that detects the relative distance to a reflective object by sending and receiving light or radio waves may be used.

[0024] The detection unit 30 detects a vital sign, such as respiration or pulse, based on the tension change detected by the sensor 20. For example, the detection unit 30 detects the vital sign, such as respiration or pulse, by detecting periodicity of a signal component representing a change in tension F from the output signal of the sensor 20. This is because if periodicity is detected, it is estimated that the periodic movement of the respiration or pulse of the occupant 11 wearing the seat belt 4 is being detected as a tension change by the sensor 20. The detection unit 30 detects the vital sign by extracting, using a predetermined filter, frequency components corresponding to the vital sign from the signal component representing the change in tension F detected by the sensor 20. The respiration signal has a period of about 3 to 6 seconds, and the pulse signal has a period of about 0.5 to 1 second.

[0025] The detection unit 30 may detect the magnitude of a signal component that represents a change in tension F from the output signal of the sensor 20. The detection unit 30 detects the magnitude of the tension F by detecting the magnitude of the signal component that represents a change in tension F. This is because the magnitude of the signal component corresponds to the magnitude of the tension F.

[0026] The determination unit 70 determines whether the object on the vehicle seat 2 is a passenger or a child car seat based on the detection state of the buckle switch 13 and the detection state of the vital signs by the detection unit 30. The detailed determination method will be described later. A child car seat, also known as a CRS (Child Restraint System), is one type of child restraint device. The child car seat is not limited to a car seat for infants, but may also be a car seat for school-age children.

[0027] The detection unit 30 and the determination unit 70 are, for example, integrated circuits including one or more computers (specifically, microcomputers). The detection unit 30 and the determination unit 70 may be realized by different integrated circuits, or may be integrated into a single integrated circuit. The computer has a processor such as a CPU (Central Processing Unit) and a memory. The functions of the detection unit 30 and the determination unit 70 are realized by the processor operating according to a program stored in the memory. The functions of the detection unit 30 and the determination unit 70 may also be realized by an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0028] The output unit 80 outputs the determination result by the determination unit 70 (determination result of whether it is an occupant or a child seat) to an external device of the buckle 8 via wired or wireless communication. The external device executes predetermined control based on the determination result. For example, if the external device determines that the object on the seat 2 is an occupant, it determines that an airbag needs to be deployed, and if the external device determines that the object on the seat 2 is a child seat, it determines that an airbag does not need to be deployed.

[0029] The output unit 80 outputs the determination result by the determination unit 70 to the outside of the buckle 8, for example, by a signal, light, sound, vibration, or any combination thereof.

[0030] Fig. 3 is a table showing a first example of a determination method by the determination unit. Fig. 4 is a flowchart showing a first example of a determination method by the determination unit. Note that "Empty" indicates a state in which no object is on the seat 2, and "CRS" indicates a child seat.

[0031] In step S11, the determination unit 70 determines whether or not the connection between the tongue 7 and the main body 8a is detected by the buckle switch 13. If the connection is not detected by the buckle switch 13, the determination unit 70 determines that the buckle 8 is in an unused state (step S15). On the other hand, if the connection is detected by the buckle switch 13, the determination unit 70 determines whether or not a vital sign is detected by the detection unit 30 (step S12).

[0032] If the vital signs are detected by the detection unit 30, the determination unit 70 determines that the object on the seat 2 is an occupant (step S13). On the other hand, if the vital signs are not detected by the detection unit 30, the determination unit 70 determines that the object on the seat 2 is a child seat (step S14).

[0033] 3 and 4, the determination unit 70 determines that the object is an occupant when the connection between the tongue 7 and the main body 8a is detected by the buckle switch 13 and the vital signs are detected by the detection unit 30. On the other hand, the determination unit 70 determines that the object is a child car seat when the connection between the tongue 7 and the main body 8a is detected by the buckle switch 13 and the vital signs are not detected by the detection unit 30. In this way, by using the vital signs to determine whether the object on the seat 2 is an occupant or a child car seat, it is possible to determine with high accuracy whether the object on the seat 2 is an occupant or a child car seat.

[0034] Fig. 5 is a table showing a second example of the determination method by the determination unit. Fig. 6 is a flowchart showing a second example of the determination method by the determination unit. In the second example, the same parts as in the first example will not be described.

[0035] If the connection between the tongue 7 and the main body 8a is detected by the buckle switch 13 in step S11, the determination unit 70 determines whether or not a vital sign is detected by the detection unit 30 (step S12).If a vital sign is not detected by the detection unit 30, the determination unit 70 determines whether or not the magnitude of the tension F of the seat belt detected by the detection unit 30 using the sensor 20 is equal to or greater than a predetermined threshold (step S16).

[0036] In step S16, if the magnitude of the tension F is equal to or greater than a predetermined threshold, the determination unit 70 determines that the object on the seat 2 is a child seat (step S14). This is because the tension F is relatively large when the child seat is properly secured to the seat 2 by the seat belt 4 connected to the buckle 8. On the other hand, if the magnitude of the tension F is less than the predetermined threshold, the determination unit 70 determines that the seat belt is being used improperly (step S17). This is because the tension F is relatively small when the child seat is not properly secured to the seat 2 by the seat belt 4 connected to the buckle 8.

[0037] Improper use conditions in step S17 include, for example, a state in which the child seat is not properly secured, a state in which an object other than the child seat is secured to the seat 2, a state in which the dummy tongue 7 is connected to the buckle 8, a state in which the seat belt 4 is clipped and the seat belt 4 is loose, etc.

[0038] The output unit 80 may output a warning when the determination unit 70 determines in step S17 that the seat belt is being used improperly, thereby making the occupant aware of the improper use and encouraging them to resolve the improper use.

[0039] Fig. 7 is a table showing a third example of the determination method by the determination unit. Fig. 8 is a flowchart showing a third example of the determination method by the determination unit. In the third example, the same parts as in the first and second examples will not be described.

[0040] In step S18, the determination unit 70 determines whether the presence of an object on the seat 2 has been detected by the seat sensor 90 provided on the seat 2.

[0041] The seat sensor 90 (see FIGS. 1 and 2) detects the presence of an object on the seat 2 and outputs the detection result. The seat sensor 90 is provided, for example, on the cushion (seat portion) or seat rail of the seat 2. The detection result by the seat sensor 90 is input to the determination unit 70 in the buckle 8 via a wired or wireless connection. The seat sensor 90 outputs an output signal that changes depending on whether or not an object is present on the seat 2.

[0042] The seat sensor 90 is, for example, a load sensor that detects the load applied to the seat 2 by strain or capacitance. If there is no object on the seat 2 or if the object on the seat 2 is a relatively light item, the load applied to the seat 2 is less than a predetermined load value, and it is detected that there is no object. If there is a passenger or a child seat on the seat 2, the load applied to the seat 2 is equal to or greater than the predetermined load value, and it is detected that there is an object.

[0043] 8, if the seat sensor 90 does not detect the presence of an object, the determination unit 70 determines that the seat 2 is vacant (step S19). On the other hand, if the seat sensor 90 detects the presence of an object, the determination unit 70 determines whether the object on the seat 2 is a passenger or a child seat (steps S11 to S15). By using the detection result of the seat sensor 90, it is possible to determine whether the seat is vacant or not.

[0044] Fig. 9 is a table showing a fourth example of the determination method by the determination unit. Fig. 10 is a flowchart showing a fourth example of the determination method by the determination unit. The fourth example is a method in which the processes of steps S18 and S19 of the third example (Figs. 7 and 8) are added to the second example (Figs. 5 and 6). According to the fourth example, the effects of both the second and third examples can be obtained.

[0045] Next, a specific example of a buckle according to the present embodiment will be described. For ease of understanding, the scale of each part in the drawings may differ from the actual scale. Misalignment in directions such as parallel, right-angled, orthogonal, horizontal, vertical, up-down, and left-right is permitted to the extent that it does not impair the effects of the embodiment. The shape of the corners is not limited to right angles and may be rounded like an arch. The X-axis, Y-axis, and Z-axis directions represent directions parallel to the X-axis, Y-axis, and Z-axis, respectively. The X-axis, Y-axis, and Z-axis directions are perpendicular to each other. The XY plane, YZ plane, and ZX plane represent imaginary planes parallel to the X-axis and Y-axis directions, imaginary planes parallel to the Y-axis and Z-axis directions, and imaginary planes parallel to the Z-axis and X-axis directions, respectively.

[0046] Fig. 11 is a front view of the appearance of the buckle according to the first embodiment. Fig. 12 is a cross-sectional view of the buckle according to this embodiment taken along line AA. The X-axis direction represents the width direction of the buckle 8. The Y-axis direction represents the height direction of the buckle 8 when mounted on a vehicle. The Z-axis direction represents the thickness direction of the buckle 8.

[0047] Fig. 13 is an exploded perspective view of the buckle according to this embodiment. Fig. 14 is an exploded perspective view of some components of the buckle according to this embodiment. As shown in Figs. 13 and 14, the buckle 8 (main body 8a) includes a buckle main body 8c, a circuit board 16, an upper cover 12, a lower cover 14, a lever 40, and a leaf spring 50.

[0048] The buckle body 8c is a sub-assembly that can be connected to a tongue attached to a seat belt. The buckle body 8c has, for example, a button 31 that is pushed by the occupant's finger to release the connection between the tongue and the buckle, and a buckle base 37 that holds the components of the buckle body 8c, such as the button 31. The buckle body 8c is formed with an insertion opening 15 through which the metal plate of the tongue is inserted.

[0049] The upper cover 12 is a resin part that covers the buckle body 8c so as to expose the button 31. The upper cover 12 holds the buckle body 8c by sandwiching it between itself and the lower cover 14. In this embodiment, a lever 40 is attached to the upper cover 12. The lever 40 has a pivot 41 that protrudes in the X-axis direction and is supported by the upper cover 12 so as to be rotatable about the pivot 41.

[0050] In this embodiment, the circuit board 16 includes the components shown in FIG. 2 (the sensor 20, the Hall sensor 13a of the buckle switch 13, the detection unit 30, the determination unit 70, and the output unit 80).

[0051] The lower cover 14 is an example of a buckle cover having an inner surface to which the circuit board 16 is fixed. The lower cover 14 is a resin part that covers the circuit board 16.

[0052] The upper cover 12 and the lower cover 14 are outer covers of the buckle 8, and are housings that house the buckle body 8c, the circuit board 16, the lever 40, and the leaf spring 50. In this embodiment, in order to house these components, the outer cover of the buckle 8 is made up of two components, the upper cover 12 and the lower cover 14, but it may be made up of three or more components.

[0053] When the buckle 8 is attached to the vehicle, the upper cover 12 faces the side opposite to the occupant wearing the seat belt connected to the buckle 8 via the tongue, and the lower cover 14 faces the occupant.

[0054] 15, 16, and 17 are cross-sectional views illustrating a mechanism for detecting the tension of a seat belt. When the tongue 7 is inserted into the buckle 8 (see FIG. 15), the tip of the tongue 7 comes into contact with the ejector 33. The ejector 33 is pushed by the contact with the tip of the tongue 7 and moves in the direction in which the tongue 7 is inserted, causing the latch 34 to rotate and the slider 32 to move down. As the latch 34 rotates, the latch 34 engages with the tongue 7, and the slider 32 moves below the lock pin 35 (see FIG. 16).

[0055] The insertion opening 15 is a gap between the button 31 and the lever 40. The opening height e of the insertion opening 15 (see FIG. 15) is determined by the height of the gap. The lever 40 and the leaf spring 50 are formed so that the opening height e of the insertion opening 15 when the lever 40 is in its initial position is slightly narrower than the plate thickness d of the tongue 7. Therefore, in FIG. 16, when the tongue 7 is inserted into the insertion opening 15, the lever 40 is pushed by the tongue 7 at the application point P2, causing it to rotate slightly clockwise around the pivot 41. The leaf spring 50 is pushed in by the lever 40, which is rotating slightly. The elastic force of the leaf spring 50 pushed in by the lever 40 suppresses rattle of the tongue 7 between the button 31 and the lever 40. As a result, minute changes in the tension F of the seat belt are accurately transmitted to the sensor 20 via the tongue 7, the lever 40, and the leaf spring 50. As a result, the sensor 20 can detect minute changes in the tension F with high accuracy.

[0056] In FIG. 17 , a load (tension F) applied to a force point P1 of the tongue 7 causes the tongue 7 to press the upper surface of the lever 40 at a point of application P2, with the upper wall 37a of the buckle base 37 as a fulcrum P3. The lever 40, pressed by the tongue 7 at the point of application P2, rotates clockwise around the pivot 41 and presses the leaf spring 50. The leaf spring 50 receives the load and transmits the force to the sensor 20 while bending. The lower wall 37b of the buckle base 37 has a mechanical stopper that restricts movement of the tongue 7 toward the lower wall 37b. When the tongue 7 comes into contact with the mechanical stopper, movement of the tongue 7 toward the lower wall 37b is stopped. The mechanical stopper limits the force applied to the sensor 20 via the lever 40 and the leaf spring 50, thereby protecting the sensor 20 from large loads due to collisions, etc.

[0057] 18 is a block diagram showing an example of the configuration of a buckle according to the second embodiment. Descriptions of the second embodiment that are similar to those of the first embodiment, in terms of configuration, action, and effect, will be omitted or simplified by citing the above description.

[0058] In the first embodiment (see FIG. 2), the determination unit 70 and the output unit 80 are provided in the buckle 8, whereas in the second embodiment (see FIG. 18), the determination unit 70 and the output unit 80 are provided in a separate device located in a different location from the buckle 8. The determination system 100 shown in FIG. 18 includes the buckle 8, the determination unit 70, and the output unit 80, and may further include a seat sensor 90.

[0059] In the second embodiment, the buckle 8 includes a buckle switch 13, a sensor 20, and a detection unit 30. The determination unit 70 and the output unit 80 are realized by a determination device such as an electronic control unit (ECU) mounted on the vehicle. According to the second embodiment, the determination device (determination unit 70) outside the buckle 8 can determine with high accuracy whether an object on the vehicle seat 2 is an occupant or a child seat.

[0060] Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and various modifications and improvements are possible, such as combinations with or substitutions for part or all of other embodiments.

[0061] For example, the seat 2 may be a front seat or a rear seat of the vehicle. In addition, in Fig. 18, the detection unit 30 may be provided in a separate device disposed at a location different from the buckle 8, and the separate device may be the same device as the determination unit 70 or a different device. [Explanation of symbols]

[0062] 1 Seat belt device 4 Seatbelts 7 Tongue 8 Buckle 8a Main body 8b Stay 8c buckle body 12 Upper cover 13 Buckle switch 13a Hall sensor 14 Lower cover 15 Insertion port 16 Circuit Board 20 sensors 30 Detection unit 40 Lever 41 Pivot 50 Leaf spring 70 Judgment section 80 Output section 90 Sheet Sensor 100 Judgment System

Claims

1. a main body portion connectable to a tongue attached to a seat belt of a vehicle; a buckle switch that detects whether the tongue and the main body are connected; a sensor for detecting a change in tension of the seat belt; a detection unit that detects a vital sign, such as respiration or pulse, based on the change in tension detected by the sensor; a determination unit that determines whether an object on a seat of the vehicle is a passenger or a child seat based on a detection state of the buckle switch and a detection state of the vital signs, A buckle in which, when the connection is detected by the buckle switch and the vital signs are not detected by the detection unit, the determination unit determines the state of the child seat based on the magnitude of tension of the seat belt detected using the sensor.

2. 2. The buckle according to claim 1, wherein the determination unit determines that the object is an occupant when the connection is detected by the buckle switch and the vital signs are detected by the detection unit, and determines that the object is a child seat when the connection is detected by the buckle switch and the vital signs are not detected by the detection unit.

3. 3. The buckle according to claim 2, wherein the determination unit determines that the object is a child seat when the connection is detected by the buckle switch, the vital signs are not detected by the detection unit, and the tension of the seat belt detected using the sensor is equal to or greater than a threshold value.

4. 4. The buckle according to claim 3, wherein the determination unit determines that the seat belt is being used improperly when the connection is detected by the buckle switch, the vital signs are not detected by the detection unit, and the tension of the seat belt detected using the sensor is less than a threshold value.

5. 5. The buckle according to claim 4, wherein the improper use state is a state in which the child car seat is not properly secured.

6. The buckle according to claim 1 , wherein the determination unit determines whether the object is a passenger or a child seat when the presence of the object is detected by a seat sensor provided in the seat.

7. The buckle according to claim 6 , wherein the determination unit determines that the seat is vacant when the presence of the object is not detected by the seat sensor.

8. a buckle that can be coupled to a tongue attached to a seat belt of a vehicle; a determination device disposed at a location different from the buckle, The buckle is a buckle switch that detects whether the tongue and the buckle are connected; a sensor for detecting a change in tension of the seat belt; a detection unit that detects a vital sign, such as respiration or pulse, based on the change in tension detected by the sensor; the determination device determines whether an object on a seat of the vehicle is an occupant or a child seat based on a detection state of the buckle switch and a detection state of the vital signs, The determination device determines the state of the child seat based on the magnitude of tension of the seat belt detected using the sensor when the connection is detected by the buckle switch and the vital signs are not detected by the detection unit.

9. a seat sensor provided on the seat to detect the presence of the object; The determination system according to claim 8 , wherein the determination device determines whether the object is a passenger or a child seat when the presence of the object is detected by the seat sensor.

10. The buckle switch detects whether the tongue attached to the vehicle's seat belt is connected to the buckle, A sensor provided in the buckle detects a change in tension of the seat belt, Detecting a vital sign, such as respiration or pulse, based on the detected tension change; a determination method for determining whether an object on a seat of the vehicle is a passenger or a child seat based on the detection state of the connection and the detection state of the vital sign, A determination method in which, when the connection is detected by the buckle switch and the vital signs are not detected by the detection unit, the state of the child seat is determined based on the magnitude of the tension of the seat belt detected using the sensor.

11. The buckle according to claim 1 , wherein the determination unit determines whether the vital sign is detected by the detection unit when the connection is detected by the buckle switch.

12. The buckle according to claim 11, wherein the determination unit determines that the object is an occupant when the vital sign is detected by the detection unit, and determines that the object is a child seat when the vital sign is not detected by the detection unit.

13. The buckle according to claim 12, wherein the determination unit, when the vital signs are not detected by the detection unit, determines whether the magnitude of the tension of the seat belt detected by the detection unit using the sensor is equal to or greater than a predetermined threshold.

14. The buckle according to claim 13, wherein the determination unit determines that the object is a child seat when the magnitude of the tension is equal to or greater than a threshold, and determines that the seat belt is being used improperly when the magnitude of the tension is less than the threshold.

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