Vehicular seat

Abstract

To provide a vehicular seat that is configured so that accuracy in determining seating is not impaired even when an inclination of a seating face is changed.SOLUTION: A vehicular seat 1 comprises: a seat cushion 4 that supports the hip of a user from below; a seating sensor 20 provided on the seat cushion 4; a seating face angle changing device 11 that changes a seating face angle θ which is an angle formed by a floor surface R of a vehicle and a seating face S of the seat cushion 4; and a control device 16 that determines whether the user is seated on the seat cushion 4 or not on the basis of a result of comparison of a detected pressure value detected by the seating sensor 20 with a predetermined threshold. The control device 16 corrects the threshold on the basis of the seating face angle θ, in determining whether the user is seated.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a vehicle seat having a seating sensor.

Background Art

[0002] Patent Document 1 describes a vehicle seat having a seating sensor. The seating determination is made by the seating sensor, and the determination result is used, for example, to determine the necessity of an alarm in a seat belt reminder (SBR) system that issues an alarm when the seat belt is not worn.

[0003] In addition, Patent Document 2 describes a vehicle seat in which the inclination of the seating surface of the seat cushion can be changed between a forward-downward state in which the front part of the seating surface of the seat cushion is lower than the rear part and a forward-upward state in which the front part of the seating surface is higher than the rear part.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The seating sensor detects the pressure applied to the seat cushion. Therefore, when the seating sensor is applied to a seat in which the inclination of the seating surface of the seat cushion is changed like the vehicle seat described in Patent Document 2, the pressure detected by the seating sensor changes depending on the inclination of the seating surface, and there is a risk that the accuracy of the seating determination is impaired.

[0006] In view of the above background, an object of the present invention is to provide a vehicle seat in which the accuracy of the seating determination is not impaired even when the inclination of the seating surface is changed.

Means for Solving the Problem

[0007] In order to solve the above problems, an aspect of the present invention is a vehicle seat (1) provided on the floor of a vehicle (V), having a seat cushion (4) that supports the user's buttocks from below, the vehicle seat being provided with a seating sensor (20) that is provided on the seat cushion and detects the pressure applied to the seat cushion, and a seat surface angle changing device (11) for changing the seat surface angle (θ), which is the angle formed by the floor surface (R) of the vehicle and the seating surface (S) of the seat cushion, in the forward-upward direction and the forward-downward direction from the normal position, and a control device (16) configured to receive the detected pressure value detected by the seating sensor and perform a seating determination for determining the presence or absence of the user's seating on the seat cushion based on a comparison between the detected pressure value and a predetermined threshold value. The control device is configured to correct the threshold value or the detected pressure value based on the seat surface angle in the seating determination.

[0008] According to this aspect, since the threshold value or the detected pressure value is corrected based on the seat surface angle, even if the seat surface angle affects the detected pressure value of the seating sensor, the accuracy of the seating determination is not impaired.

[0009] In the above aspect, the control device (16) may be configured to correct the threshold value or the detected pressure value in the seating determination when the seat surface angle (θ) deviates from the angle in the normal position by more than a predetermined value. Here, the "predetermined value" is a value of 0 or more, and "deviating by more than a predetermined value" includes both the case of deviating in the forward-upward direction and the case of deviating in the forward-downward direction.

[0010] According to this aspect, a predetermined range from the normal position can be set as a range in which the threshold value or the detected pressure value is not corrected, and the threshold value can be corrected only when the detected pressure value is significantly affected by the seating sensor.

[0011] In the above aspect, when the seat cushion (4) is positioned in the forward rising direction beyond the predetermined value from the normal position, the control device (16) may correct the threshold value used in the seating determination to a larger value, or correct the detected pressure value to a smaller value.

[0012] In this aspect, when the actual detected pressure value of the seating sensor becomes larger than the detected pressure value in the normal position, by setting the threshold value used in the seating determination to a larger value, the accuracy of the seating determination is not impaired.

[0013] In the above aspect, when the seat cushion (4) is positioned in the forward lowering direction beyond the predetermined value from the normal position, the control device (16) may correct the threshold value used in the seating determination to a smaller value, or correct the detected pressure value to a larger value.

[0014] In this aspect, when the actual detected pressure value of the seating sensor becomes smaller than the detected pressure value in the normal position, by setting the threshold value used in the seating determination to a smaller value, the accuracy of the seating determination is not impaired.

[0015] In the above aspect, the seating sensor (20) may be provided at a position corresponding to the thigh portion of the user on the seat cushion (4).

[0016] According to this aspect, it is difficult for abnormal values to occur in the change of the detected pressure value according to the change of the seat surface angle, and the accuracy of the seating determination is not impaired.

[0017] In the above aspect, the seating sensor (20) may be provided at a position corresponding to the buttocks of the user on the seat cushion (4).

[0018] According to this aspect, it is difficult for abnormal values to occur in the change of the detected pressure value according to the change of the seat surface angle, and the accuracy of the seating determination is not impaired.

[0019] In the above aspect, a plurality of the seating sensors (20) are provided on the seat cushion (4), and the control device (16) may weight the threshold value or the detected pressure value corresponding to the seating sensor according to the position of each of the seating sensors in the seat cushion.

[0020] According to this aspect, by using a plurality of seating sensors, the accuracy of the seating sensors is improved.

[0021] In the above aspect, the control device (16) may compare each of the detected pressure values of the seating sensors (20) with the threshold value, and determine that the user is seated when the detected pressure values of a predetermined number or more of the seating sensors exceed the threshold value.

[0022] According to this aspect, even when the detected pressure value of some of the seating sensors becomes an abnormal value, it is difficult to affect the seating determination.

[0023] In the above aspect, the control device (16) may perform the seating determination based on a comparison between a representative value obtained by weighting each of the detected pressure values of the seating sensors (20) according to the position of each of the seating sensors in the seat cushion (4) and correction based on the seat surface angle (θ), and one of the threshold values.

[0024] According to this aspect, even when the detected pressure value of some of the seating sensors becomes an abnormal value, it is difficult to affect the seating determination.

[0025] In the above aspect, further including an output device (14), the control device (16) may control the output device to issue a warning when the seat surface angle (θ) is equal to or greater than a predetermined angle and it is determined that the user is seated.

[0026] According to this aspect, when the seat cushion is tilted so much that it is not suitable for sitting, a warning can be issued to the user.

Advantages of the Invention

[0027] One aspect of the present invention is a vehicle seat (1) provided on the floor of a vehicle (V), having a seat cushion (4) that supports the user's buttocks from below, the seat cushion being provided with a seating sensor (20) for detecting the pressure applied to the seat cushion, and a seat surface angle changing device (11) for changing the seat surface angle (θ), which is the angle formed by the floor surface (R) of the vehicle and the seating surface (S) of the seat cushion, in the forward-upward direction and the forward-downward direction from the normal position, and a control device (16) configured to receive the detected pressure value detected by the seating sensor and perform a seating determination for determining the presence or absence of the user's seating on the seat cushion based on a comparison between the detected pressure value and a predetermined threshold value. The control device is configured to correct the threshold value or the detected pressure value based on the seat surface angle in the seating determination.

[0028] According to this aspect, since the threshold value or the detected pressure value is corrected based on the seat surface angle, even if the seat surface angle affects the detected pressure value of the seating sensor, the accuracy of the seating determination is not impaired.

[0029] In the above aspect, the control device (16) may be configured to correct the threshold value or the detected pressure value in the seating determination when the seat surface angle (θ) deviates from the angle in the normal position by more than a predetermined value. Here, the "predetermined value" is a value of 0 or more, and "deviating by more than the predetermined value" includes both the case of deviating in the forward-upward direction and the case of deviating in the forward-downward direction.

[0030] According to this aspect, a predetermined range from the normal position can be set as a range in which the threshold value or the detected pressure value is not corrected, and the threshold value can be corrected only when the detected pressure value is significantly affected by the seating sensor.

[0031] In the above aspect, when the seat cushion (4) is positioned in the forward-upward direction beyond the predetermined value from the normal position, the control device (16) may correct the threshold value used in the seating determination to a larger value or correct the detected pressure value to a smaller value.

[0032] In this aspect, when the actual detected pressure value of the seating sensor becomes larger than the detected pressure value in the normal position, by setting the threshold value used for the seating determination to a large value, the accuracy of the seating determination is not impaired.

[0033] In the above aspect, when the seat cushion (4) is located in the forward-downward direction beyond the predetermined value from the normal position, it is preferable that the control device (16) corrects the threshold value used in the seating determination to a small value, or corrects the detected pressure value to a large value.

[0034] In this aspect, when the actual detected pressure value of the seating sensor becomes smaller than the detected pressure value in the normal position, by setting the threshold value used for the seating determination to a small value, the accuracy of the seating determination is not impaired.

[0035] In the above aspect, the seating sensor (20) may be provided at a position corresponding to the thigh portion of the user on the seat cushion (4).

[0036] According to this aspect, it is difficult for abnormal values to occur in the change of the detected pressure value according to the change of the seat surface angle, and the accuracy of the seating determination is not impaired.

[0037] In the above aspect, the seating sensor (20) may be provided at a position corresponding to the buttocks of the user on the seat cushion (4).

[0038] According to this aspect, it is difficult for abnormal values to occur in the change of the detected pressure value according to the change of the seat surface angle, and the accuracy of the seating determination is not impaired.

[0039] In the above aspect, a plurality of the seating sensors (20) are provided on the seat cushion (4), and the control device (16) may weight the threshold value or the detected pressure value corresponding to the seating sensor according to the position of each seating sensor in the seat cushion.

[0040] According to this aspect, by using a plurality of seating sensors, the accuracy of the seating sensors is improved.

[0041] In the above aspect, the control device (16) may compare each of the detected pressure values of the seating sensors with the threshold value, and determine that the user is seated when the detected pressure values of a predetermined number or more of the seating sensors exceed the threshold value.

[0042] According to this aspect, even when the detected pressure values of some of the seating sensors become abnormal values, it is difficult to affect the seating determination.

[0043] In the above aspect, the control device (16) may perform the seating determination based on a comparison between a representative value after performing the weighting according to the position of each of the seating sensors (20) in the seat cushion (4) and the correction based on the seat surface angle (θ) for each of the detected pressure values of the seating sensors, and one of the threshold values.

[0044] According to this aspect, even when the detected pressure values of some of the seating sensors become abnormal values, it is difficult to affect the seating determination.

[0045] In the above aspect, further having an output device (14), the control device (16) may control the output device to issue a warning when the seat surface angle (θ) is a predetermined angle or more and it is determined that the user is seated.

[0046] According to this aspect, when the seat cushion is tilted so much that it is not suitable for sitting, a warning can be issued to the user.

Brief Description of the Drawings

[0047]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0048] Hereinafter, with reference to the drawings, a vehicle seat 1 according to an embodiment of the present invention will be described. FIG. 1 shows a deformed state of the vehicle seat 1, FIG. 2 shows a configuration of a vehicle V including the vehicle seat 1, and FIG. 3 is a block diagram of a system 2 related to the vehicle seat 1. In the following description, unless otherwise specified, the "front-rear direction", "left-right direction", and "up-down direction" mean the front-rear direction, left-right direction, and up-down direction of the vehicle V. Also, a direction based on the vehicle seat 1, such as the "seat front-rear direction", means the direction as seen from a user seated on the vehicle seat 1.

[0049] <<First Embodiment>> As shown in FIGS. 1 and 2, the vehicle seat 1 is installed on the floor 3 in the passenger compartment of the vehicle V. The vehicle seat 1 includes a seat cushion 4, a seat back 5 supported at the rear of the seat cushion 4, and a headrest 6 connected to the upper part of the seat back 5. The seat cushion 4 supports the user's buttocks from below, the seat back 5 supports the user's back from the rear in the seat front-rear direction, and the headrest 6 supports the user's head from the rear in the seat front-rear direction. The seat cushion 4 and the seat back 5 each include a frame, a pad supported by the frame, and a skin material covering the surface of the pad on the user side (not shown).

[0050] On the floor 3, a rotating device 8 is supported via a slide device 7. The rotating device 8 rotatably supports a support member 9 with respect to the slide device 7 about a vertical axis Z passing through substantially the center in the front-rear direction of the seat and the width direction of the seat. At the front end of the support member 9 or in the vicinity thereof, the front end of the seat cushion 4 is tiltably connected about a tilting axis Y1 in the width direction of the seat. A seat surface angle changing actuator 10 that can expand and contract in its extending direction is pivotally connected at one end to a position below and / or behind the seat with respect to the tilting axis Y1 of the support member 9 and at the other end to a position behind the seat of the seat cushion 4 about an axis in the width direction of the seat. As the seat surface angle changing actuator 10, an electric cylinder, an air cylinder or a hydraulic cylinder having a motor may be used.

[0051] An angle that varies about the tilting axis Y1 formed by a reference plane R (floor surface) orthogonal to the vertical direction and the seating surface S of the seat cushion 4 is defined as a seat surface angle θ (thigh angle). The support member 9 and the seat surface angle changing actuator 10 constitute a main part of a seat surface angle changing device 11 for changing the seat surface angle θ. Since the seating surface S deforms during actual sitting, strictly speaking, it is set with reference to the seat frame. When viewed from the side of the seat, the tilting axis Y1 and the two pivotable connection points to the support member 9 and the seat cushion 4 of the seat surface angle changing actuator 10 are not arranged on the same straight line, that is, they are arranged to form the vertices of a triangle. Therefore, when the seat surface angle changing actuator 10 expands and contracts, the seat surface angle θ is changed. The seat surface angle changing device 11 can tilt the seat cushion 4 about the tilting axis Y1 between a state where the front end of the seating surface S is tilted downward with respect to the reference plane R (a state where the seat surface angle θ is negative, see Fig. 1(A)) and a state where the front end of the seating surface S is tilted upward with respect to the reference plane R (a state where the seat surface angle θ is positive, see Fig. 1(C)).

[0052] In the illustrated example, the tilting axis Y1 is arranged at the front end of the seat cushion 4, but the tilting axis Y1 may be arranged at any position from the front end to the rear end of the seat cushion 4, and the seat surface angle changing device 11 may have a configuration that allows the seat cushion 4 to tilt with respect to the reference plane R.

[0053] As shown in FIGS. 2 and 3, the system 2 includes an in-vehicle monitoring device 12 that acquires information inside the vehicle cabin, an out-of-vehicle monitoring device 13 that acquires information outside the vehicle cabin, an input / output device 14 that receives and provides information to the user, a vehicle state monitoring device 15 that acquires information regarding the state of the vehicle V, a control device 16 that receives information from the in-vehicle monitoring device 12, the out-of-vehicle monitoring device 13, the input / output device 14, and the vehicle state monitoring device 15 and transmits the information to the input / output device 14, and a plurality of controlled devices 17 controlled by the control device 16.

[0054] The in-vehicle monitoring device 12 includes one or more in-vehicle cameras 18 that image the interior of the vehicle cabin, a plurality of object sensors 19 provided on the vehicle seat 1, a seating sensor 20 provided on the seat cushion 4, a biological sensor 21, and a seat surface angle sensor 22.

[0055] The in-vehicle camera 18 is disposed at a position where it can image the user and the periphery of the vehicle seat 1. The in-vehicle camera 18 may be configured by a CMOS image sensor. The in-vehicle camera 18 is preferably configured by a compound eye camera including a plurality of imaging elements and capable of distance imaging based on triangulation such as stereo measurement or light sectioning method.

[0056] The object sensor 19 is a sensor that detects an object inside the vehicle, and may be a proximity sensor, a lidar, an ultrasonic sensor, or the like. Alternatively, the object sensor 19 may be configured by a ToF (Time of Flight) sensor module that includes a light source and a detector and performs distance measurement by acquiring the time until the light emitted from the light source reaches the detector. The object sensor 19 may be disposed, for example, along the outer peripheral surface of the seat cushion 4, or may be provided at an appropriate position on the headrest 6. Further, the object sensors 19 may be arranged side by side in the front-rear direction on the door panel or the floor 3.

[0057] The seating sensor 20 may be a membrane switch or an electrostatic sensor provided on the seat cushion 4. The seating sensor 20 detects the pressure applied to the seat cushion 4, and the control device 16 that has received the detection result determines whether the user is sitting on the vehicle seat 1. A seat belt reminder (SBR) system that issues an alarm when the user is sitting on the vehicle seat 1 but not wearing a seat belt is adopted, and a seating determination using the seating sensor 20 is performed to determine whether an alarm is necessary or not.

[0058] The biological sensor 21 may be a heartbeat sensor, a respiration sensor, a pressure sensor, or an electroencephalogram sensor. The heartbeat sensor is provided on the front surface of the seat back 5, and preferably, is arranged at a position corresponding to the user's heart. The heartbeat sensor is a sensor that detects the user's heart rate. The heartbeat sensor may be based on any of a touch type, an optical type, and an electrocardiogram type. The respiration sensor is a sensor that detects the user's respiration rate and the depth of respiration. The respiration sensor may be, for example, a type that detects the pressure applied from the user at a position corresponding to the user's lungs on the front surface of the seat back 5 and reads the pressure change caused by the user's respiratory movement. The respiration sensor may be based on a type that provides two sheet-like electrodes along the front surface of the seat back 5 and detects the variation in the capacitance between the electrodes due to the movement of the human chest. The pressure sensor is a sensor used to detect the user's posture based on the pressure applied to the seat cushion 4 and the seat back 5. The pressure sensor is provided in a planar shape on the surfaces of the seat cushion 4 and the seat back 5 facing the user, measures the in-plane distribution (pressure distribution) of the pressure applied from the user to them, and detects the user's posture. The electroencephalogram sensor includes a magnetic sensor provided at a position facing the user's head in the headrest 6. The magnetic sensor detects the magnetic signal associated with the activity of the user's brain cells. The electroencephalogram sensor calculates the user's electroencephalogram based on the magnetic signal. As the electroencephalogram sensor, a magnetic sensor provided at a position facing the user's head in the headrest 6 may be used, and the control device 16 may calculate the user's electroencephalogram based on the magnetic signal.

[0059] The seat surface angle sensor 22 is provided between the support member 9 and the frame of the seat cushion 4, or in the seat surface angle changing actuator 10, and detects the seat surface angle θ (see FIG. 1) or information for calculating the seat surface angle θ.

[0060] The outside-vehicle monitoring device 13 includes one or more outside-vehicle photographing cameras 23, and a plurality of radars 24 and / or lidars 25 (LiDARs).

[0061] The outside-vehicle photographing camera 23 images the surroundings of the vehicle V, including objects existing around the vehicle V (for example, surrounding vehicles and pedestrians), guardrails, curbs, walls, median strips, the shape of the road, and road markings drawn on the road. The outside-vehicle photographing camera 23 may be, for example, a digital camera using a solid-state imaging device such as a CCD or a CMOS. The outside-vehicle photographing camera 23 is provided, for example, on the ceiling inside the vehicle compartment, and images the outside of the vehicle compartment through the front glass, the rear glass, or the side glass. The outside-vehicle photographing camera 23 may be, for example, a stereo camera.

[0062] The radar 24 emits radio waves such as millimeter waves around the vehicle V, and detects the position (distance and direction) of an object by capturing the reflected wave. The lidar 25 irradiates light such as infrared rays around the vehicle V, and detects the position (distance and direction) of an object by capturing the reflected light. The radar 24 and / or the lidar 25 are attached outside the vehicle compartment of the vehicle V. The radar 24 and / or the lidar 25 include, for example, those that irradiate radio waves / light forward of the vehicle V, those that irradiate radio waves / light rearward of the vehicle V, and those that irradiate radio waves / light laterally of the vehicle V. The outside-vehicle monitoring device 13 may include a sonar.

[0063] The input / output device 14 receives input operations by the user and notifies the user of various information by display or sound. The input / output device 14 may include, for example, a touch panel 26 that performs both input and output. Further, in addition to or instead of the touch panel 26, the input / output device 14 may include an input device (e.g., buttons, switches, and / or a microphone 27 that receives the user's voice input) and an output device (e.g., a display and / or a speaker 28 that notifies sound). A mobile terminal such as a smartphone may be communicable with the control device 16 wirelessly or by wire and used as the input / output device 14.

[0064] The vehicle state monitoring device 15 includes a vehicle speed sensor 29, a brake sensor 30, a steering angle sensor 31, a shift lever sensor 32, and a door sensor 33. The vehicle speed sensor 29 detects the vehicle speed of the vehicle V. The brake sensor 30 includes a brake pedal sensor that detects the depression amount of the brake pedal and a parking brake sensor that detects the operation amount of the parking brake lever. The steering angle sensor 31 detects the steering angle of the steering wheel. The shift lever sensor 32 detects where the shift lever is placed, such as in parking (P), reverse (R), neutral (N), drive (D), etc. The door sensor 33 detects the open / closed state of the door of the vehicle V.

[0065] The control device 16 is a so-called Electronic Control Unit, which controls the vehicle seat 1 based on the information acquired by the in-vehicle monitoring device 12, the out-of-vehicle monitoring device 13, and the vehicle state monitoring device 15, as well as the information input by the user to the input / output device 14. The control device 16 is composed of a computer including a processor 34 constituted by a CPU (Central Processing Unit) or the like, and a storage device 35 including a RAM (Random Access Memory), a ROM (Read Only Memory), and an SSD (Solid State Drive) and / or an HDD (Hard Disk Drive). The control device 16 is connected to the in-vehicle monitoring device 12, the out-of-vehicle monitoring device 13, the input / output device 14, the vehicle state monitoring device 15, and the control target device 17 so that signals can be transmitted and received by signal lines or wirelessly. The control device 16 and the control target device 17 are connected to a power source (not shown) mounted on the vehicle V and receive power supply from the power source. The control device 16 can acquire information regarding the vehicle seat 1, such as the state of the seat surface angle θ (see FIG. 1), based on the information acquired by the in-vehicle monitoring device 12 and the control history for the control target device 17.

[0066] The control target device 17 controlled by the control device 16 includes, in addition to the above-described slide device 7, rotation device 8, and seat surface angle changing device 11, a reclining device 36 that tilts the seat back 5, an airbag device 37 that protects the user during a collision of the vehicle V, a side support device 38 that changes the height of both side portions of the seat cushion 4, a seat heater 39 that warms the seat cushion 4, and a vibration device 40 that vibrates the seat cushion 4 to prompt the user's attention.

[0067] The control device 16 can calculate the seat surface angle θ from the detected value of the seat surface angle sensor 22. The seat surface angle sensor 22 may be, for example, an angle potentiometer provided between the support member 9 and the seat cushion 4. Further, the seat surface angle sensor 22 may be a stroke sensor that detects the length of the seat surface angle change actuator 10, and the control device 16 may calculate the seat surface angle θ based on the length of the seat surface angle change actuator 10. The control device 16 may also calculate the seat surface angle θ from the control history of the seat surface angle change actuator 10.

[0068] The user can change the seat surface angle θ by operating the input / output device 14. The input / output device 14 outputs an operation signal corresponding to the user's operation to the control device 16. The control device 16 controls the seat surface angle change actuator 10 based on the operation signal to change the seat surface angle θ to an angle within the changeable range. The changeable range is the range of angles at which the seat surface angle θ can be changed, and is defined by the minimum angle (see Fig. 1(A)) and the maximum angle (see Fig. 1(C)). The changeable range is set by the control device 16.

[0069] The reclining device 36 is a device that tilts the seat back 5 with respect to the seat cushion 4 around a tilting axis Y2 (see Fig. 1) extending in the seat width direction. The tilting axis Y2 extends to the rear end in the front-rear direction of the seat of the seat cushion 4 and the lower end of the seat back 5.

[0070] FIG. 4 is an explanatory diagram showing the magnitude of the pressure applied from the user to the seating sensor 20 in the states where (A) the seat cushion 4 is lowered forward from the normal position, (B) the seat cushion 4 is disposed at the normal position, and (C) the seat cushion 4 is raised forward from the normal position. As shown in FIG. 4, the seating sensor 20 is provided at a position corresponding to the user's thigh portion on the seat cushion 4, that is, at the front portion of the seat cushion 4. When the seat cushion 4 is displaced in the forward-rising direction from the normal position, it is considered that the user's thigh portion is pressed against the seat cushion 4, and the pressure applied to the seating sensor 20 increases. Further, when the seat cushion 4 is displaced in the forward-lowering direction from the normal position, it is considered that the user's thigh portion lifts off from the seat cushion 4, and the pressure applied to the seating sensor 20 decreases.

[0071] In addition, even when the seating sensor 20 is provided at a position corresponding to the user's buttocks on the seat cushion 4, that is, at the rear portion of the seat cushion 4, when the seat cushion 4 is displaced in the forward-rising direction, since the user's center of gravity moves backward, the pressure applied to the seating sensor 20 increases, and when it is displaced in the forward-lowering direction, since the user's center of gravity moves forward, the pressure applied to the seating sensor 20 decreases.

[0072] As shown in FIGS. 3 and 4, the seating sensor 20 detects the pressure applied to the seat cushion 4, and the control device 16 determines whether the user is seated on the seat cushion 4 based on a comparison between the detected pressure value of the seating sensor 20 and a predetermined threshold value. The seating determination is performed, for example, by determining the truth or falsehood of the following formula (1) or formula (2). P > P0 + k1 ··· (1) P > k2P0 ··· (2) Here, P is the detected pressure value detected by the seating sensor 20, P0 is the threshold value, k1 is the correction value, and k2 is the correction coefficient. In equations (1) and (2), seemingly, the threshold value is corrected. However, equation (1) can be rewritten as P - k1 > P0, and equation (2) can be rewritten as P / k2 > P0. In the rewritten equations, seemingly, the detected pressure value is corrected. Therefore, correcting the threshold value is synonymous with correcting the detected pressure value. Correcting the detected pressure value to a value smaller than the measured value corresponds to correcting the threshold value to a value larger than the standard value, and correcting the detected pressure value to a value larger than the measured value corresponds to correcting the threshold value to a value smaller than the standard value. Hereinafter, unless otherwise specified, the description of "correcting the threshold value" is used in the sense of including both the case where the control device 16 corrects the threshold value and the case where the control device 16 corrects the detected pressure value in the program executed by the control device 16.

[0073] Figure 5 shows a flowchart of the seating determination. With reference to FIGS. 3 to 5, the procedure of the seating determination will be described. The control device 16 acquires the detected pressure value of the seating sensor 20 (ST1) and acquires the seat surface angle θ at that time from the seat surface angle sensor 22 (ST2). Instead of acquiring the seat surface angle θ from the seat surface angle sensor 22, it may be acquired based on the control history of the seat surface angle changing device 11 by the control device 16.

[0074] The control device 16 determines whether the acquired seat surface angle θ exceeds a predetermined angle α above the seat surface angle θ (hereinafter referred to as "normal angle θ0") when the seat cushion 4 is disposed at the normal position (ST3), or is below the normal angle θ0 by more than the predetermined angle α (ST4). Here, α is an angle of 0° or more, and α in ST3 and α in ST4 may be the same value as each other or may be different values from each other.

[0075] When the obtained seat surface angle θ does not exceed the normal angle θ0 by more than a predetermined angle α (No in ST3) and does not fall below the normal angle θ0 by more than the predetermined angle α (No in ST4) (Fig. 4(B)), the control device 16 does not correct the threshold value used for the seating determination in relation to the seat surface angle θ (ST5). For example, when the control device 16 performs the seating determination using Equation (1), the correction value k1 is set to 0, and when using Equation (2) for the seating determination, the correction coefficient k2 is set to 1.

[0076] When the obtained seat surface angle θ is less than the normal angle θ0 by more than a predetermined angle α (No in ST3 and Yes in ST4, Fig. 4(A)), it is considered that the pressure applied to the seating sensor 20 becomes smaller than when the seat cushion 4 is in the normal position. Therefore, the control device 16 corrects the threshold value used for the seating determination to a smaller value (ST6). The smaller the seat surface angle θ, the larger the correction amount may be. For example, when the control device 16 performs the seating determination using Equation (1), the correction value k1 is set to a negative value, and when using Equation (2) for the seating determination, the correction coefficient k2 is set to a value greater than 0 and less than 1. The smaller the seat surface angle θ, the smaller the value of k1 or k2 may be.

[0077] When the obtained seat surface angle θ exceeds the normal angle θ0 by more than a predetermined angle α (Yes in ST3, Fig. 4(C)), it is considered that the pressure applied to the seating sensor 20 becomes larger than when the seat cushion 4 is in the normal position. Therefore, the control device 16 corrects the threshold value used for the seating determination to a larger value (ST7). The larger the seat surface angle θ, the larger the correction amount may be. For example, when the control device 16 performs the seating determination using Equation (1), the correction value k1 is set to a positive value, and when using Equation (2) for the seating determination, the correction coefficient k2 is set to a value greater than 1. The larger the seat surface angle θ, the larger the value of k1 or k2 may be.

[0078] The control device 16 performs the seating determination based on the threshold value set in any of ST5 to ST7 (ST8). The control device 16 may use the result of the seating determination to determine the necessity of an alarm in a seat belt reminder system (not shown).

[0079] When a plurality of seating sensors 20 are provided, the detected pressure values differ depending on the positions of the seating sensors 20 within the seat cushion 4. For example, the detected pressure value of the seating sensor 20 provided at the center in the seat width direction is higher than the detected pressure values of the seating sensors 20 provided at both side portions in the seat width direction, and the detected pressure value of the seating sensor 20 provided at the rear portion of the seat corresponding to the user's buttocks is higher than the detected pressure value of the seating sensor 20 provided at the front portion of the seat corresponding to the user's thighs. The control device 16 performs weighting on the detected pressure value or the threshold value so as to cope with such differences. The control device 16 corrects the threshold value as necessary for each of the seating sensors 20 to perform a seating determination, and may determine that the user is seated when the seating determination is affirmed for a predetermined number or more of the seating sensors 20. Further, the control device 16 performs weighting according to the position on each of the pressure values detected by the seating sensors 20 and correction according to the seat surface angle θ, and compares a representative value such as an average value, a median value, or a mode value thereof with the threshold value to perform a seating determination.

[0080] As described above, by correcting the detected pressure value of the seating sensor 20 based on the seat surface angle θ, the accuracy of the seating determination is not impaired even in the vehicle seat 1 in which the seat surface angle θ can be changed.

[0081] By setting a predetermined angle α, it is possible to provide an angle range in which the threshold value is not corrected, and the threshold value can be corrected only when the detected pressure value is significantly affected by the seating sensor 20. By providing a plurality of seating sensors 20 and performing weighting according to their positions, the accuracy of the seating determination is improved.

[0082] Although the description of the specific embodiments has been completed above, the present invention is not limited to the above embodiments and can be widely modified and implemented. For example, the vehicle seat 1 may be provided in a vehicle other than the vehicle V. The correction of the threshold value in the seating determination may be performed based on factors such as the inclination of the vehicle V in addition to the seat surface angle θ. When the control device 16 determines that the user is seated at a large seat surface angle θ (for example, 40 to 50° or more) at which there is a risk that the user cannot sit on the seat cushion 4 in a safe state, the control device 16 may control the input / output device 14 such as the touch panel 26 and the speaker 28 to issue a warning.

Explanation of Reference Numerals

[0083] 1: Vehicle seat 4: Seat cushion 11: Seat surface angle changing device 16: Control device 20: Seating sensor 22: Seat surface angle sensor R: Reference plane (floor surface) S: Seating surface V: Vehicle θ: Seat surface angle

Claims

1. A vehicle seat having a seat cushion that supports a user's buttocks from below and is provided on a floor of the vehicle, a seating sensor provided on the seat cushion and configured to detect a pressure applied to the seat cushion; a seat angle changing device for changing a seat angle, which is an angle between a floor surface of the vehicle and a seating surface of the seat cushion, from a normal position in a front upward direction and a front downward direction; a control device configured to receive a detected pressure value detected by the seating sensor and perform a seating determination to determine whether or not the user is seated on the seat cushion based on a comparison between the detected pressure value and a predetermined threshold value, The control device is configured to correct the threshold value or the detected pressure value based on the seating surface angle in the seating determination.

2. 2. The vehicle seat according to claim 1, wherein the control device is configured to correct the threshold value or the detected pressure value when, in the seating determination, the seat surface angle deviates from an angle in the normal position by more than a predetermined value.

3. 3. The vehicle seat according to claim 2, wherein the control device corrects the threshold value used in the seating determination to a larger value or corrects the detected pressure value to a smaller value when the seat cushion is positioned in the forward upward direction beyond the normal position and beyond the predetermined value.

4. 3. The vehicle seat according to claim 2, wherein the control device corrects the threshold value used in the seating determination to a smaller value or corrects the detected pressure value to a larger value when the seat cushion is positioned in the forward downward direction beyond the predetermined value from the normal position.

5. 5. The vehicle seat according to claim 3, wherein the seating sensor is provided at a position on the seat cushion corresponding to a thigh of the user.

6. 5. The vehicle seat according to claim 3, wherein the seating sensor is provided at a position on the seat cushion corresponding to buttocks of the user.

7. The seating sensor is provided in plurality on the seat cushion, 5. The vehicle seat according to claim 3, wherein the control device weights the threshold value or the detected pressure value corresponding to each of the seating sensors in accordance with a position of the seating sensor within the seat cushion.

8. 8. The vehicle seat according to claim 7, wherein the control device compares the detected pressure value of each of the seating sensors with the threshold value, and determines that the occupant is seated when the detected pressure values ​​of a predetermined number or more of the seating sensors exceed the threshold value.

9. 8. The vehicle seat according to claim 7, wherein the control device performs the seating determination based on a comparison between a representative value of the detected pressure values ​​of the seating sensors after the weighting according to the position of each of the seating sensors in the seat cushion and the correction based on the seat surface angle are performed on the detected pressure values ​​of each of the seating sensors and one of the threshold values.

10. An output device is further included. The vehicle seat according to claim 1 , wherein the control device controls the output device to issue a warning when it is determined that the seat angle is equal to or greater than a predetermined angle and the user is seated.

Images