Vehicle seats

Abstract

To provide a seat for a vehicle capable of securing safety of an occupant even when there is abnormality in a headrest.SOLUTION: A seat S for a vehicle has a seat cushion 2, a seatback 1, a reclining mechanism 7 for angle-adjustably supporting the seatback 1 to the seat cushion 2, a headrest 3 having a projection mechanism 31 of projecting a side part forward, an abnormality detection part 40 for detecting abnormality of the projection mechanism 3 and a control part 50 for controlling operation of the reclining mechanism 7 and the projection mechanism 31, and when the abnormality detection part 40 detects the abnormality of the projection mechanism 31, and when a backward projection angle θ of the seatback 1 exceeds a prescribed angle β, the control part 50 performs seatback reinstall processing for rotating the seatback 1 until the backward inclination angle θ of the seatback 1 becomes the prescribed angle β, and when the backward inclination angle θ of the seatback 1 is equal to or less than the prescribed angle β, the control part 50 performs seatback rotation prohibition processing for prohibiting rotation of the seatback 1.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a vehicle seat, and more particularly to a vehicle seat having a headrest with a protruding mechanism. [Background technology]

[0002] Patent Document 1 discloses a vehicle seat that, when the seatback is fully reclined rearward (relaxed state), the side portions of the headrest provided on the outer sides in the vehicle width direction protrude forward to cover the sides of the occupant's head, thereby protecting the occupant's head from a side collision. It also describes that the function of the side portions protruding forward is activated when the vehicle seat is the driver's seat and the vehicle is in autonomous driving mode, but is not activated when the vehicle is in manual driving mode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-46208 Summary of the Invention [Problem to be solved by the invention]

[0004] The vehicle seat described in Patent Document 1 uses a curtain airbag to protect the occupant's head during a side collision. If the seatback is tilted rearward too far, the occupant's head falls outside the area that can be protected by the curtain airbag, and the occupant's head is protected by the side portions of the headrest. However, if the headrest malfunctions for some reason and the side portions no longer protrude forward, the occupant's head may not be adequately protected if the seatback is relaxed. Therefore, there is a need for a vehicle seat that ensures the safety of the occupant even when there is a problem with the headrest.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a vehicle seat that can ensure the safety of an occupant even if there is an abnormality in the headrest. [Means for solving the problem]

[0006] The above problem is solved by a vehicle seat provided in a vehicle, the vehicle seat comprising: a seat cushion; a seat back rotatably attached to the seat cushion; a reclining mechanism supporting the seat back so that the angle of the seat back is adjustable relative to the seat cushion; a headrest provided at the upper end of the seat back and having a protrusion mechanism whose sides protrude forward; an abnormality detection unit that detects an abnormality in the protrusion mechanism; and a control unit that controls the operation of the reclining mechanism and the protrusion mechanism; when the abnormality detection unit detects an abnormality in the protrusion mechanism, if the rearward tilt angle of the seat back exceeds a predetermined angle with respect to the vertical direction, the control unit performs a seat back return process that rotates the seat back using the reclining mechanism until the rearward tilt angle of the seat back reaches the predetermined angle, and when the rearward tilt angle of the seat back is equal to or less than the predetermined angle, the control unit performs a seat back rotation prohibition process that prohibits the seat back from being rotated by the reclining mechanism.

[0007] In the vehicle seat described above, if the abnormality detection unit detects an abnormality in the headrest protruding mechanism, the control unit rotates the seat back until the rearward tilt angle reaches a predetermined angle, and prohibits the seat back from rotating if the rearward tilt angle of the seat back falls below the predetermined angle. Because the seat back does not tilt further rearward than the predetermined angle, the occupant's head can be positioned within the protection range of, for example, a curtain airbag installed in the vehicle, ensuring the safety of the occupant even if an abnormality occurs in the protruding mechanism.

[0008] In addition, in the above-mentioned vehicle seat, the side portions that protrude forward are provided on each of the left and right sides of the headrest, and the abnormality in the protruding mechanism is that at least one of the side portions provided on the left and right sides cannot protrude forward. By detecting an abnormality in one of the left and right side portions, the seat back can be returned to its original position or the seat back rotation can be inhibited, thereby ensuring the safety of the occupants.

[0009] In addition, in the above-mentioned vehicle seat, the side portions that protrude forward are provided on each of the left and right sides of the headrest, and the abnormality in the protruding mechanism is that at least the side portion of the left and right side portions that is closest to the window of the vehicle cannot be protruded. By performing the seat back return process and the seat rotation prohibition process only when an abnormality is detected at least in the side area close to the window side of the vehicle, it is possible to avoid performing the seat back return process and the seat rotation prohibition process when, for example, only an abnormality is detected in the side area inside the vehicle. This allows the occupant to continue in a relaxed state in the vehicle seat. On the other hand, if an abnormality is detected in the side area close to the window side, the seat back return process and the seat rotation process are performed, thereby ensuring the safety of the occupant.

[0010] Furthermore, in the above-mentioned vehicle seat, when the abnormality detection unit detects an abnormality in the protruding mechanism, the control unit may transmit an abnormality detection signal to a vehicle control unit that controls the vehicle, indicating that the abnormality in the protruding mechanism has occurred. The control unit transmits an abnormality detection signal to the vehicle control unit, allowing the vehicle control unit to perform control corresponding to the abnormality in the protrusion function.

[0011] Furthermore, in the above-mentioned vehicle seat, when the abnormality detection unit detects an abnormality in the protruding mechanism, the control unit may notify the vehicle occupant via the vehicle control unit or directly that the seat back return process or the seat back rotation prohibition process is being performed due to the detection of the abnormality in the protruding mechanism. The occupant is notified that a seat return process or a seat back rotation prohibition process is being performed due to the detection of an abnormality in the protruding mechanism, thereby giving the occupant a sense of security.

[0012] In the vehicle seat, the notification may be performed using at least one of a sound generating means, a video display means, a lighting means, and a vibration generating means provided in the vehicle. By using at least one of the sound generating means, the image display means, the lighting means, and the vibration generating means, it is possible to reliably notify the occupant of the detection of an abnormality.

[0013] Furthermore, in the above-mentioned vehicle seat, the vehicle control unit can switch the vehicle between an automatic driving mode and a manual driving mode, and when the abnormality detection unit detects an abnormality in the protrusion mechanism, if the vehicle is in the automatic driving mode, the control unit may send a mode switching signal to the vehicle control unit to switch from the automatic driving mode to the manual driving mode. When the side portions of the headrest cannot be protruded, the vehicle can be driven more safely by switching to the manual driving mode.

[0014] Furthermore, in the above-mentioned vehicle seat, the vehicle control unit can switch the vehicle between an automatic driving mode and a manual driving mode, and when the abnormality detection unit detects an abnormality in the protrusion mechanism, an automatic driving prohibition signal that prohibits the vehicle from switching to the automatic driving mode is sent to the vehicle control unit. When the side portions of the headrest cannot be protruded, the vehicle can be driven more safely by prohibiting the transition to the automatic driving mode and leaving only the manual driving mode.

[0015] Furthermore, in the vehicle seat described above, the side portions that protrude forward are provided on each of the left and right sides of the headrest, and the abnormality in the protruding mechanism is that at least one of the side portions provided on the left and right sides cannot return from the protruding state to its normal state, and when the abnormality detection unit detects the abnormality in the protruding mechanism, the control unit may send an abnormality detection signal to a vehicle control unit that controls the vehicle, indicating that the abnormality in the protruding mechanism has occurred. If the abnormality in the protruding mechanism is that the side cannot be returned from the protruding state to the normal state, the control unit sends an abnormality detection signal to the vehicle control unit indicating that the abnormality has occurred, and the vehicle control unit can then perform control corresponding to the abnormality.

[0016] Furthermore, in the above-mentioned vehicle seat, the vehicle control unit can switch the vehicle between an automatic driving mode and a manual driving mode, and when the abnormality detection unit detects an abnormality in the protrusion mechanism, if the vehicle is in manual driving mode, the control unit switches the vehicle to the automatic driving mode using the vehicle control unit and performs safety operation processing to cause the vehicle to move safely. If the side cannot be returned to its normal state from its protruding state, it would be dangerous to drive manually, so the vehicle can be driven safely by switching to automatic driving mode and performing safety operation processing.

[0017] In the vehicle seat described above, the control unit may prohibit the vehicle control unit from switching to the manual driving mode. By prohibiting switching to the manual driving mode, the vehicle can be driven more safely.

[0018] In addition, in the above-mentioned vehicle seat, the control unit may notify the vehicle occupant, via the vehicle control unit or directly, that the safety operation processing is being performed because an abnormality in the protruding mechanism has been detected. By notifying the occupant that a safety operation process is being carried out due to the detection of an abnormality in the protruding mechanism, the occupant is given a sense of security.

[0019] In the vehicle seat, the notification may be performed using at least one of a sound generating means, a video display means, a lighting means, and a vibration generating means provided in the vehicle. By using at least one of the sound generating means, the image display means, the lighting means, and the vibration generating means, it is possible to reliably notify the occupant of the detection of an abnormality.

[0020] In the vehicle seat described above, the vehicle control unit can switch the vehicle between an automatic driving mode and a manual driving mode, and when the abnormality detection unit detects the abnormality of the protrusion mechanism, the vehicle is in the automatic driving mode and Vehicle When the manual driving mode is selected by the occupant, the control unit may perform a second safety operation process by using the vehicle control unit to switch the vehicle to the manual driving mode and cause the vehicle to move safely. Even while in manual driving mode, the control unit can ensure the safety of occupants while driving manually by having the vehicle control unit notify, for example, a dealer or the like, that a malfunction has occurred in the headrest as a second safety operation process. [Effects of the Invention]

[0021] According to the vehicle seat of the present invention, when an abnormality detection unit provided in the seat back detects an abnormality in the headrest protruding mechanism, if the rearward tilt angle of the seat back exceeds a predetermined angle, the control unit rotates the seat back until the rearward tilt angle reaches the predetermined angle, and if the rearward tilt angle of the seat back is below the predetermined angle, the control unit prohibits the seat back from rotating. Because the seat back does not tilt further rearward than the predetermined angle, the occupant's head can be positioned within the protection range of, for example, a curtain airbag provided in the vehicle, ensuring the safety of the occupant even if there is an abnormality in the protruding mechanism. Furthermore, by detecting an abnormality in one of the left and right side portions, the seat back can be returned to its original position or the seat back rotation can be inhibited, thereby ensuring the safety of the occupants. Furthermore, by performing the seat back return process and the seat rotation process only when an abnormality is detected at least in the side portion close to the window side of the vehicle, for example, if only an abnormality is detected in the side portion on the interior side, the seat back return process and the seat rotation process can be omitted, allowing the relaxed state of the vehicle seat to continue.On the other hand, if an abnormality is detected in the side portion close to the window side, the seat back return process and the seat rotation process can be performed, thereby ensuring the safety of the occupant. Furthermore, the control unit transmits an abnormality detection signal to the vehicle control unit, which allows the vehicle control unit to perform control in response to the abnormality in the protruding function. In addition, the occupant is notified that a seat return process or a seat back rotation prohibition process is being performed due to the detection of an abnormality in the protruding mechanism, thereby providing the occupant with a sense of security. Furthermore, by using at least one of the sound generating means, the image display means, the lighting means, and the vibration generating means, it is possible to reliably notify the occupant of the detection of an abnormality. Furthermore, when the side portions of the headrest cannot be protruded, the vehicle can be driven more safely by switching to the manual driving mode. Furthermore, if the side portions of the headrest cannot be protruded, the vehicle can be driven more safely by prohibiting the vehicle from switching to the automatic driving mode and leaving only the manual driving mode. Furthermore, if the abnormality in the protruding mechanism is that the side portion cannot be returned from the protruding state to the normal state, the control unit will send an abnormality detection signal to the vehicle control unit indicating that the abnormality has occurred, allowing the vehicle control unit to perform control corresponding to the abnormality. Furthermore, if the side cannot be returned to its normal state from its protruding state, it would be dangerous to drive manually, so the vehicle can be driven safely by switching to automatic driving mode and performing safety operation processing. Furthermore, by prohibiting switching to the manual driving mode, the vehicle can be driven more safely. In addition, by notifying the occupant that a safety operation process is being carried out due to the detection of an abnormality in the protruding mechanism, the occupant is given a sense of security. Furthermore, by using at least one of the sound generating means, the image display means, the lighting means, and the vibration generating means, it is possible to reliably notify the occupant of the detection of an abnormality. Even while in manual driving mode, the control unit can ensure the safety of the occupants by having the vehicle control unit perform a second safety operation process, for example, notifying a dealer or the like that a malfunction has occurred in the headrest. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a perspective view showing the appearance of a vehicle seat according to an embodiment of the present invention; [Figure 2] FIG. 1 is a side view showing a vehicle seat. [Figure 3] FIG. 1 is a plan view of a headrest used in a vehicle seat. [Figure 4] FIG. 1 is a front view of a headrest used in a vehicle seat. [Figure 5] 1 is a schematic side view showing a state in which a seat back is tilted rearward beyond a predetermined angle with respect to the vertical direction in a vehicle equipped with a vehicle seat; [Figure 6] 1 is a block diagram showing the configuration of a vehicle seat, a seat control device mounted in the vehicle, and a vehicle control device; [Figure 7] 10 is a flowchart showing an example of a control flow of the control device when the side portion of the headrest does not enter a protruding state. [Figure 8] 10 is a flowchart showing an example of a control flow of the control device when a side portion of the headrest does not return from a protruding state. DETAILED DESCRIPTION OF THE INVENTION

[0023] The configuration of a vehicle seat according to one embodiment of the present invention will be described below with reference to the drawings. However, the embodiment described below is intended to facilitate understanding of the present invention and is not intended to limit the present invention. In other words, the present invention may be modified or improved without departing from the spirit thereof, and of course, the present invention also includes equivalents thereof. In the following description, the contents regarding the materials, shapes, and sizes of the seat components are merely examples and do not limit the present invention.

[0024] In the following, a vehicle seat mounted on a vehicle will be taken as an example of a vehicle seat, and an example of its configuration will be described. However, the present invention is not limited to vehicle seats mounted on ground vehicles having wheels such as automobiles and trains, and can also be applied to seats mounted on aircraft, ships, and other vehicles that move on non-ground surfaces.

[0025] In the following description, the "front-rear direction" refers to the front-rear direction of the vehicle seat, which is the direction that coincides with the direction of travel when the vehicle is traveling. The "seat width direction" refers to the width direction of the vehicle seat (in other words, the width direction of the seat body), which is the direction that coincides with the left-right direction as seen by an occupant seated in the vehicle seat. The "up-down direction" refers to the up-down direction of the vehicle seat, which is the direction that coincides with the vertical direction when the vehicle is traveling on a horizontal plane.

[0026] In addition, the "outside" and "window side" in the seat width direction refer to the side closer to the outside of the vehicle body (or, more simply, the side closer to the nearest door or window), while the "inside" and "interior" refer to the side closer to the inside of the vehicle body (or, more simply, the side farthest from the nearest door). In the following description, unless otherwise specified, "rotation" means a rotational movement about an axis along the sheet width direction.

[0027] The shapes, positions, and postures of the various parts of the vehicle seat described below will be described assuming that the vehicle seat is in an occupied state, unless otherwise specified.

[0028] The basic configuration of a vehicle seat (hereinafter referred to as vehicle seat S) according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a perspective view of a vehicle seat S mounted on a vehicle V such as an automobile, and for convenience of illustration, a cushion trim cover T and a pad P are removed from part of the vehicle seat S in Fig. 1.

[0029] <<Vehicle Seat S>> The vehicle seat S is disposed on a vehicle body floor F that defines the bottom of the vehicle interior R, and is a seat in which an occupant H of the vehicle V sits. In this embodiment, the vehicle seat S is used as a front seat corresponding to the front seat of the vehicle. It is disposed to the side of the driver's seat and forms a passenger seat. However, the vehicle seat S is not limited to this, and may be used as a driver's seat or a rear seat. In a vehicle with three rows of seats in the longitudinal direction, the vehicle seat S may be used as a middle seat in the second row or a rear seat in the third row. As shown in FIG. 1, doors D are provided on the exterior sides of the driver's seat and passenger seat for occupants to get in and out of the vehicle V. Each door D is provided with a window W for occupants to view the left and right sides of the vehicle V.

[0030] As shown in FIG. 1, the vehicle seat S includes a seat back 1, which serves as a backrest portion supporting the back of the seated occupant, a seat cushion 2, which serves as a seating portion supporting the buttocks of the seated occupant, and a headrest 3, which supports the head of the occupant. The seatback 1 is also provided with a reclining mechanism 7 that supports the seatback 1 so that the angle can be adjusted relative to the seat cushion 2, and the seatback 1 is attached to the seat cushion 2 so that it can rotate. The headrest 3 is also provided with protruding mechanisms 31 that protrude forward on the left and right side portions. Below, the seat back 1 and the seat cushion 2 will be described, and then the headrest 3 having the protruding mechanisms 31 will be described in detail.

[0031] <Seatback 1> The seat back 1 extends in the vertical direction and has a roughly rectangular parallelepiped shape with a surface facing roughly in the front-to-rear direction. The front surface of the seat back 1 forms a support surface 1a that supports the back of the occupant H. The support surface 1a is recessed rearward at roughly the center in the left-to-right direction and is inclined slightly rearward upward. As a result, the support surface 1a is shaped to correspond to the back of the occupant H, and the back of the occupant H is supported by the support surface 1a.

[0032] <Seat cushion 2> The seat cushion 2 is a substantially rectangular parallelepiped with a surface facing substantially in the vertical direction, and the upper surface of the seat cushion 2 forms a seating surface 2a for one occupant. The seating surface 2a is recessed downward approximately in the center in the left-right direction and is inclined slightly downward toward the rear in the front-to-rear direction. As a result, the seating surface 2a is shaped to accommodate the buttocks and thighs of the occupant H, and when the occupant H sits, the buttocks and thighs of the occupant H are placed on the seating surface 2a. The seat back 1 and the seat cushion 2 may be collectively referred to as a seat body Sh.

[0033] <Pad P and cushion trim cover T> A seat back frame (not shown) that forms the framework of the seat back 1 is provided inside the seat back 1. A seat cushion frame (not shown) that forms the framework of the seat cushion 2 is also provided inside the seat cushion 2. A pad P and a cushion trim cover T (cushion cover) are provided around the seat cushion frame and the seat back frame. The pad P is a urethane base material molded by foam molding using, for example, a urethane foam material, and the cushion trim cover T is made of a covering material such as cloth, synthetic leather, or genuine leather.

[0034] <Reclining mechanism 7> As shown in Fig. 2, the vehicle seat S has a reclining function that changes the rearward tilt angle θ of the seat back 1 relative to the vertical direction. More specifically, a known reclining mechanism 7 is provided at the lower end of the seat back 1, and the seat back 1 is rotatably supported on the rear end of the seat cushion 2. The seat back 1 is connected to the seat cushion 2 so that it can rotate and adjust its angle relative to the seat cushion 2. The reclining mechanism 7 is a mechanism that adjusts the rearward tilt angle θ of the seat back 1 relative to the vertical direction, and the seat back 1 is connected to the rear end of the seat cushion 2 at the lower end so that it can be tilted forward and backward.

[0035] As an example, the reclining mechanism 7 includes a reclining rod 71 (rotating shaft) connected to a rod (not shown) arranged in the seat width direction at the lower end of the seatback 1, and a guide 72 that rotatably supports the reclining rod 71. The vehicle seat S further includes a reclining drive unit 73 (see FIG. 6) that rotates the reclining rod 71. The reclining drive unit 73 that rotates the reclining rod 71 is configured by, for example, a motor.

[0036] The vehicle seat S also includes a reclining angle detector 74 (see FIG. 6) that detects the rearward tilt angle θ of the seat back 1 relative to the vertical direction. The reclining angle detector 74 is provided, for example, on the reclining rod 71 at a position opposite to the guide 72.

[0037] <Slide Rail 21> 1, a slide rail 21 is installed under the vehicle seat S. The slide rail 21 allows the vehicle seat S to be attached to the vehicle floor F in a state where it can slide in the front-rear direction.

[0038] The slide rail 21 is a device for sliding the vehicle seat S in the front-rear direction and has a known structure (the structure of a general slide rail mechanism). The slide rail 21 has a lower rail fixed to the vehicle body floor F and an upper rail that is slidable relative to the lower rail. The upper rail is slidable relative to the lower rail that is fixed to the vehicle body. The vehicle seat S is also provided with a seat belt device 22 (see FIG. 2) equipped with a shoulder belt for restraining the occupant H.

[0039] <Headrest 3> As shown in Figures 1 to 4, the headrest 3 is disposed above the seat back 1 along the seat width direction, and is formed in a horizontally elongated shape such that the length in the seat width direction is longer than the length in the seat front-rear direction.

[0040] The headrest 3 is of a so-called butterfly type, and has a protruding mechanism 31 that protrudes forward on both left and right side portions. In this embodiment, the headrest 3 has, as the protruding mechanism 31, a main portion 32 connected to the upper end of the seatback 1 via two headrest pillars 32a, a left portion 33L provided on the left side of the main portion 32, and a right portion 33R provided on the right side of the main portion 32. The main portion 32 faces substantially forward and has a substantially rectangular surface (main contact surface 34). The main portion 32 abuts against the rear surface of the head of a seated occupant H at the main contact surface 34, and supports the rear surface of the head of the occupant H from behind.

[0041] The left side portion 33L has a substantially rectangular parallelepiped shape. As shown in FIG. 3 , the left side portion 33L is connected to the left edge of the main contact surface 34 at one ridgeline via a hinge 35L and is rotatably connected to the main portion 32 about an axis extending in the vertical direction. This allows the left side portion 33L to be displaced between a use position where one wall surface (hereinafter, the left contact surface 36L) faces substantially forward and is continuous with the main contact surface 34, and a support position where the left contact surface 36L faces rightward and is located to the left of the head of the occupant H. When the left side portion 33L is in the support position, the angle between the left contact surface and the main contact surface is preferably 85 degrees or more and 105 degrees or less, and is approximately 95 degrees in this embodiment. The hinge 35L is provided with a coil spring (not shown) that biases the left side portion 33L toward the use position.

[0042] The right side portion 33R has a substantially rectangular parallelepiped shape. One ridge of the right side portion 33R is connected to the right edge of the main contact surface via a hinge 35R, and is rotatably connected to the main portion 32 about an axis extending in the vertical direction. This allows the right side portion 33R to be displaced between a use position (dashed two-dot line) in which one wall surface (hereinafter, the right contact surface 36R) faces substantially forward and is continuous with the main contact surface 34, and a support position (solid line) in which the right contact surface 36R faces leftward and is positioned to the right of the occupant's head. When the right side portion 33R is in the support position, the angle between the right contact surface 36R and the main contact surface 34 is preferably between 85 degrees and 105 degrees, both inclusive, and is approximately 95 degrees in this embodiment. The hinge 35R is provided with a coil spring (not shown) that biases the right side portion 33R toward the use position.

[0043] <Left drive unit 37L, right drive unit 37R> An actuator (hereinafter, referred to as left drive unit 37L) that rotates the left side portion 33L relative to the main portion 32 is provided between the main portion 32 and the left side portion 33L. An actuator (hereinafter, referred to as right drive unit 37R) that rotates the right side portion 33R relative to the main portion 32 is provided between the main portion 32 and the right side portion 33R. In this embodiment, as shown in FIG. 3 , the left drive unit 37L and the right drive unit 37R are supported on the left and right sides of the corresponding main portion 32 so as to be rotatable about an axis extending in the vertical direction. The left drive unit 37L and the right drive unit 37R are each extendable and retractable. As shown in FIG. 3 , extension and retraction of the left drive unit 37L rotates the left side portion 33L about the axis of the hinge 35L, displacing it between a use position (dashed two-dot line) and a support position (solid line). Extension and retraction of the right drive unit 37R also displaces the right side portion 33R between a use position and a support position.

[0044] <Left display 38L, right display 38R> 4, displays 38L and 38R are provided as image display means on the left contact surface 36L of the left side portion 33L and the right contact surface 36R of the right side portion 33R, respectively. The displays 38L and 38R are thin-film organic EL displays, and are adhered to the left contact surface 36L and the right contact surface 36R, respectively. Hereinafter, the display provided on the left side portion 33L will be referred to as the left display 38L, and the display provided on the right side portion 33R will be referred to as the right display 38R.

[0045] <Light-emitting device> In the headrest 3 of this embodiment, displays 38L, 38R are provided on the left side 33L and right side 33R, but the displays 38L, 38R may be replaced by a light-emitting device 42 (illumination means) made up of a plurality of LED elements arranged substantially horizontally. The light-emitting device 42 is connected to a seat control device 50, which will be described later. The light-emitting device 42 can notify the occupant H of a message or the like by the seat control device 50 controlling the light emission and timing of each of the LED elements included in the light-emitting device 42.

[0046] <Left speaker 39L, right speaker 39R> As shown in FIG. 4, the left contact surface 36L of the left side portion 33L and the right contact surface 36R of the right side portion 33R are provided with speakers 39L and 39R, respectively, as sound generating means. The speakers 39L and 39R are disposed above the displays 38L and 38R, respectively, and are adhered to the left and right contact surfaces 36L and 36R, respectively. The speakers 39L, 39R are each connected to the seat control device 50, which will be described later. The seat control device 50 can emit beeps, alarms, voice messages, music, etc. from the speakers 39L, 39R. Hereinafter, the speaker provided on the left side part 33L will be referred to as the left speaker 39L, and the speaker provided on the right side part 33R will be referred to as the right speaker 39R.

[0047] An abnormality detection unit 40 that detects abnormalities in the left drive unit 37L and the right drive unit 37R is also provided inside the main unit 32. The abnormality detection unit 40 measures, for example, the number of rotations of a motor provided to extend and retract the left drive unit 37L and the right drive unit 37R. If the number of rotations of the motor does not reach a predetermined number of rotations even though the left drive unit 37L and the right drive unit 37R are being driven, the abnormality detection unit 40 determines that the left side section 33L or the right side section 33R has not rotated and is not at an appropriate angle. The abnormality detection unit 40 is not limited to this detection method, and may use optical sensors 41 provided on the left and right sides of the main unit 32 to detect whether the left side unit 33L and the right side unit 33R are in the use position or the support position. When the abnormality detection unit 40 detects an abnormality in the protrusion mechanism 31, it outputs an abnormality detection signal indicating the abnormality to the seat control device 50, which will be described later. The optical sensors 41 may be laser sensors, lidar sensors, etc.

[0048] <Seat control device 50> The vehicle seat S is provided with a seat control device 50 that controls the reclining mechanism 7, the protruding mechanism 31, etc. The seat control device 50 is disposed, for example, below the seat cushion 2. FIG. 6 is a block diagram showing the configuration of the seat control device 50. The seat control device 50 is a microcomputer that includes a central processing unit (CPU 51), storage devices such as a ROM 52 and a RAM 53, a communication interface 54, etc. The CPU 51, ROM 52, RAM 53, and communication interface 54 are connected via a bus 55.

[0049] The seat control device 50 is also connected to the reclining mechanism 7, the protruding mechanism 31 of the headrest 3, the left display 38L, the right display 38R, the left speaker 39L, the right speaker 39R, the vibrator 11, and the abnormality detection unit 40, which are provided in the headrest 3. More specifically, the seat control device 50 outputs signals via a communication interface 54 to the left drive unit 37L and the right drive unit 37R of the protruding mechanism 31, the left display 38L and the right display 38R of the headrest 3, the speakers 39L and 39R, the vibrator 11, and the light-emitting device 42. The seat control device 50 also receives a signal from the abnormality detection unit 40 via the communication interface 54. The ROM 52 stores a program for controlling the positions of the seat back 1 and the side portions of the headrest 3 of the vehicle seat S. The program stored in the ROM 52 is loaded into the RAM 53 and executed by the CPU 51, thereby controlling the seat back 1 to tilt backward (recline) to a predetermined angle β and the side portions 33L, 33R of the headrest 3 to protrude forward.

[0050] In the vehicle seat S, for example, when the seat back 1 is not tilted backward and the seat is in an upright position, the left side portion 33L and the right side portion 33R are arranged so as to be aligned on an extension line of the main portion 32 in the seat width direction, as shown in Figure 1. For example, when the seat back 1 is tilted backward and in a relaxed state, the seat control device 50 causes the left drive unit 37L to move the left side section 33L from the support position to the use position protruding forward of the vehicle. At the same time, the seat control device 50 causes the right side section 33R to move from the support position to the use position protruding forward of the vehicle by the right drive unit 37R, as shown by the solid lines in Figures 3 and 4. When the left side portion 33L and the right side portion 33R are moved to the use position, as shown in Figure 2, the left side portion 33L and the right side portion 33R cover the sides of the head of the occupant H, thereby protecting the head of the occupant H in the event of a side collision.

[0051] The vehicle V is provided with, for example, a vehicle control device 60 (vehicle control unit) that controls the traveling of the vehicle V. The vehicle control device 60 is provided, for example, inside a dashboard or an instrument panel located at the front of the vehicle interior (see FIG. 5). 6 is a block diagram showing the configuration of the vehicle control device 60. The vehicle control device 60 is a microcomputer equipped with a central processing unit (CPU 61), storage devices (storage units) such as a ROM 62 and a RAM 63, and a communication interface 64. The CPU 61, ROM 62, RAM 63, and communication interface 64 are connected by a bus 65.

[0052] The communication interface 64 is connected to the communication interface 54 of the seat control device 50 and can receive abnormality detection signals and the like transmitted from the seat control device 50. It is also connected to a driving mode switching unit 66 that switches the driving mode of the vehicle V and an automatic driving control unit 67 and can control the driving mode switching unit 66 and the automatic driving control unit 67. It is also connected to a monitor 68A (video display means), a speaker 68B (audio generating means), a lighting device 68C (lighting means), and a vibration device 68D (vibration generating means) provided in the vehicle cabin and can control them.

[0053] The driving mode switching unit 66 is capable of switching between an automatic driving mode and a manual driving mode. The occupant H can select the driving mode using a switch or touch panel mounted on the vehicle V, thereby switching between the automatic driving mode and the manual driving mode using the driving mode switching unit 66. When the automatic driving mode is selected, the vehicle V is driven automatically by the automatic driving control unit 67.

[0054] Furthermore, the vehicle control device 60 can control the operation of the reclining mechanism 7 via the seat control device 50. More specifically, by operating the reclining drive unit 73 of the reclining mechanism 7 and rotating the reclining rod 71, the seat back 1 can be tilted backward or returned to an upright position.

[0055] When the seat control device 50 receives a signal indicating that the autonomous driving mode has been selected from the vehicle control device 60, it activates the reclining drive unit 73 of the reclining mechanism 7 to tilt the seat back 1 significantly backward (reclined state). More specifically, it drives the reclining mechanism 7 until the rearward tilt angle θ detected by the reclining angle detection unit 74 becomes, for example, 50 degrees or more.

[0056] When the vehicle V is in automatic driving mode and the vehicle seat S is in a reclined position, the seat control device 50 activates the protruding mechanism 31 of the headrest 3 and moves the left side 33L and right side 33R of the headrest 3 to a usage position at the front of the vehicle. When the driving mode is switched from the automatic driving mode to the manual driving mode, the seat control device 50 rotates the seat back 1 forward to return it to the upright position. At this time, the left drive unit 37L and the right drive unit 37R move the left side portion 33L and the right side portion 33R of the headrest 3 to the support positions.

[0057] Fig. 5 shows the relationship between the rearward tilt angle θ of the seat back 1 relative to the vertical direction in the autonomous driving mode and the positions of the side portions 33L, 33R of the headrest 3. As shown in Fig. 5, in the autonomous driving mode, the seat back 1 is tilted backward significantly so that the rearward tilt angle θ is 50 degrees or more. At this time, the side portions 33L, 33R protrude forward, protecting the head of the occupant H.

[0058] As shown in FIG. 5 , a vehicle V has roof side rails 81 provided on an upper portion of the vehicle substantially along the longitudinal direction of the vehicle. A curtain airbag 82, serving as a head-protecting airbag for protecting the head of an occupant H in a side collision, is provided on the inner side of the roof side rail 81 in the vehicle width direction and on the rear surface side of the outer end of the roof headlining in the vehicle width direction. The vehicle V also has a front airbag 83 provided on the dashboard on the front side of the vehicle in the longitudinal direction. FIG. 5 shows the curtain airbag 82 and the front airbag 83 deployed. The curtain airbag 82 is inflated and deployed in a curtain-like manner downward in the vehicle vertical direction in a side collision, protecting the head of the occupant H in an area (protection range) overlapping with the curtain airbag 82. However, as shown in FIG. 5 , if the seatback 1 is tilted backward significantly, the head of the seated occupant H may fall outside the protection range of the curtain airbag 82. Therefore, when the rearward tilt angle θ exceeds a predetermined angle β, the side of the headrest 3 is caused to protrude forward to protect the head of the occupant H in a side collision. The predetermined angle β with respect to the vertical direction is an angle that can be protected by the curtain airbag 82, and is set to, for example, 30 degrees, between 10 degrees and 50 degrees depending on the protection range of the curtain airbag 82.

[0059] As described above, the headrest 3 is provided with the protruding mechanism 31 to protect the head of the occupant H from a side collision even when the seatback 1 is in a relaxed state. However, the protruding mechanism 31 may malfunction for some reason. If the side portions 33L, 33R of the headrest 3 do not protrude forward due to a malfunction, the occupant's head may not be adequately protected. Therefore, in the vehicle seat S of this embodiment, an abnormality detection unit 40 is provided in the headrest 3 to detect an abnormality in the protruding mechanism 31. When the abnormality detection unit 40 detects an abnormality, the seat control device 50 is configured to perform a seatback return process to return the vehicle seat S, which is in a relaxed state, to its original upright state, for example, and to prohibit transition to the relaxed state even after the vehicle seat S has returned to the upright state.

[0060] <<Control when the side does not protrude>> Next, a description will be given of an example of a specific control flow performed by the seat control device 50. Fig. 7 is a flowchart showing the control flow when either the left side portion 33L or the right side portion 33R of the protrusion mechanism 31 is unable to move from the support position to the use position, i.e., when either side portion is no longer in a state of protruding forward.

[0061] The seat control device 50 uses the abnormality detection unit 40 to check whether there is an abnormality in the protrusion mechanism 31 (step S01). At this time, for example, the abnormality detection unit 40 checks whether the motor rotates to a predetermined number of revolutions when the seat control device 50 activates the left drive unit 37L and the right drive unit 37R to move the left side section 33L and the right side section 33R from the support position to the use position. If the predetermined number of revolutions is not reached, the abnormality detection unit 40 determines that the left drive unit 37L or the right drive unit 37R is not operating normally, and sends an abnormality detection signal to the seat control device 50 indicating that the left side section 33L or the right side section 33R has not moved to the use position. Note that the method of detecting an abnormality by measuring the number of rotations of the motor is one example, and an optical sensor 41 may be used as the abnormality detection unit 40 to check whether the left side section 33L and the right side section 33R have moved to the use position when they are moved. If an abnormality detection signal is not received from the abnormality detection unit 40 (No in step S01), the seat control device 50 ends the process without taking any particular action. When the seat control device 50 receives an abnormality detection signal indicating that an abnormality has been detected from the abnormality detection unit 40, the seat control device 50 performs the next step S02. At this time, the seat control device 50 may transmit an abnormality detection signal indicating that an abnormality has been detected to the vehicle control device 60.

[0062] If an abnormality in the protruding mechanism 31 is detected (Yes in step S01), that is, if the seat control device 50 receives an abnormality detection signal, the seat control device 50 checks the state of the seat back 1 using the reclining angle detection unit 74. Specifically, the seat control device 50 obtains the rearward tilt angle θ of the seat back 1 from the reclining angle detection unit 74 and checks whether this rearward tilt angle θ exceeds a predetermined angle β (step S02).

[0063] If the backward tilt angle θ is greater than the predetermined angle β (Yes in step S02), the seat back 1 is in a relaxed state, and there is a risk that the head of the occupant H may be outside the protection range of the curtain airbag 82. Therefore, a seat back return process is performed (step S03) to rotate the seat back 1 so that the head of the occupant H returns to the protection range of the curtain airbag 82. At this time, the seat back 1 is rotated using the reclining mechanism 7 so that at least the backward tilt angle θ is equal to or less than the predetermined angle β. In addition, the rearward tilt angle θ at which the seat back 1 is in an upright state may be set as a second predetermined angle β2, and the seat back 1 may be rotated until the rearward tilt angle θ of the seat back 1 becomes the second predetermined angle β2. After the rearward tilt angle θ of the seat back 1 becomes equal to or smaller than the predetermined angle β, a seat back rotation prohibition process (step S04) is executed to prohibit the seat back 1 from returning to the relaxed state.

[0064] If the rearward tilt angle θ is smaller than the predetermined angle β (No in step S02), the head of the occupant H is within the protection range of the curtain airbag 82, and therefore a seatback rotation prohibition process is implemented to prohibit the seatback 1 from transitioning to a relaxed state (step S04). Specifically, the seatback 1 is prohibited from being rotated by the reclining mechanism 7 beyond the predetermined angle β. By prohibiting the rotation of the seatback 1, the head of the occupant H is prevented from moving out of the protection range of the curtain airbag 82.

[0065] Next, the seat control device 50 notifies the seated occupant H that it is performing the seat back return process and the seat back rotation prohibition process due to the detection of an abnormality in the headrest (step S05). By notifying the occupant H, the occupant H can know the reason why the seat back 1 has returned to the upright position, and the seat control device 50 can give the occupant H a sense of security.

[0066] This notification to the occupant H may be performed using the displays 38L, 38R, which are video display means provided in the vehicle seat S. At this time, a message indicating that the protrusion mechanism 31 has failed is displayed on the displays 38L, 38R. This notification may also be made using speakers 39L, 39R, which are sound generating means provided in the vehicle seat S. A sound indicating that the protruding mechanism 31 has failed is emitted from the speakers. At this time, the sound to be notified may be an alarm sound or the like. The seat control device 50 may also notify the driver by using a vibrator 11, which is a vibration generating means, provided in the vehicle seat S. If light-emitting devices 42, which are illumination means, are provided on the left side 33L and right side 33R of the headrest 3 instead of the displays 38L and 38R, the seat control device 50 may also notify the driver by using a combination of these. That is, the seat control device 50 notifies the occupant H by using sounds, voice, lighting, images, vibrations, etc., via the displays 38L, 38R, speakers 39L, 39R, vibrator 11, and light-emitting device 42. The notification may be performed by combining sounds, voice, lighting, images, vibrations, etc.

[0067] The notification to the occupant may be made not only using the displays 38L, 38R, etc. provided in the vehicle seat S, but also using a monitor 68A, etc. provided in the vehicle V. This notification is made by the vehicle control device 60 after the vehicle control device 60 receives an abnormality detection signal from the seat control device 50. The notification is made by sound, voice, lighting, video, vibration, etc. using the monitor 68A, speaker 68B, lighting device 68C, vibration device 68D, etc. provided in the vehicle V. The notification may be made by a combination of sound, voice, lighting, video, vibration, etc.

[0068] If the vehicle control device 60 is capable of switching between the automatic driving mode and the manual driving mode using the driving mode switching unit 66, the seat control device 50 may perform a mode switching process to send a mode switching signal to the vehicle control device 60 to switch from the automatic driving mode to the manual driving mode (step S06). In the mode switching process, when the vehicle control device 60 receives a mode switching signal from the seat control device 50, it checks the driving mode of the vehicle V, and if it is in the automatic driving mode, it switches to the manual driving mode by the driving mode switching unit 66.

[0069] If the vehicle control device 60 is capable of switching between the automatic driving mode and the manual driving mode using the driving mode switching unit 66, the seat control device 50 may send an automatic driving prohibition signal to the vehicle control device 60 prohibiting the vehicle control device 60 from switching to the automatic driving mode (step S07). When the vehicle control device 60 receives the automatic driving prohibition signal and is in the manual driving mode, it performs an automatic driving prohibition process to prevent the mode from being switched back to the automatic driving mode.

[0070] 7 is performed when an abnormality in the protruding mechanism 31 of the headrest 3 prevents at least one of the left and right side portions 33L, 33R from protruding forward. However, this control is merely an example, and the seatback return process and the seatback rotation prohibition process may be performed when an abnormality in the protruding mechanism 31 prevents at least the side portion of the left and right side portions 33L, 33R that is closest to the vehicle window, i.e., the window side portion that is closest to the curtain airbag 82, from protruding. If the window-side side portion can be protruded, the head of the occupant H can be protected even if an abnormality is detected in the opposite side portion inside the interior. Therefore, if an abnormality is detected only in the side portion inside the interior, the seat control device 50 does not need to perform the seatback return process and the seatback rotation prohibition process.

[0071] <<Control when the side part does not return from the protruding state>> Next, a description will be given of another example of the flow of control performed by the seat control device 50. Fig. 8 is a flowchart showing the flow of control when an abnormality in the protruding mechanism 31 of the headrest 3 prevents at least one of the left and right sides from returning from the use position to the support position, i.e., when the protruding state cannot be returned to the normal state. If the protruding state cannot be restored, particularly when the vehicle seat S is the driver's seat, the occupant may not be able to check the surroundings from the sides, which may make it impossible to drive safely. Therefore, it is preferable that the seat control device 50 switches the driving mode from the manual driving mode to the automatic driving mode by the vehicle control device 60, so that the vehicle V can move safely.

[0072] The seat control device 50 uses the abnormality detection unit 40 to check whether there is an abnormality in the protrusion mechanism 31 (step S101). Specifically, at this time, for example, the abnormality detection unit 40 activates the left drive unit 37L and the right drive unit 37R to move them from the use position to the support position, and checks whether the motors rotate up to a predetermined number of rotations. If the predetermined number of rotations is not reached, it is determined that the left drive unit 37L or the right drive unit 37R is not operating normally, and the abnormality detection unit 40 sends an abnormality detection signal to the seat control device 50 indicating that the left side section 33L or the right side section 33R cannot move to the support position. At this time, the abnormality detection unit 40 may use the optical sensor 41 to detect the position of the left side portion 33L or the right side portion 33R and detect that it has not been returned to the support position normally, i.e., that it has not been returned from the protruding state to the normal state.

[0073] When the abnormality detection unit 40 detects an abnormality in the protrusion mechanism 31 (Yes in step S101), that is, when the seat control device 50 receives an abnormality detection signal, the seat control device 50 checks the state of the seat back 1 using the reclining angle detection unit 74. Specifically, the seat control device 50 acquires the rearward tilt angle θ of the seat back from the reclining angle detection unit 74 and checks whether this rearward tilt angle θ exceeds a predetermined angle β (step S102).

[0074] If the backward tilt angle θ is greater than the predetermined angle β (Yes in step S102), the seat back 1 is in a relaxed state, and so a seat back return process is performed to rotate the seat back 1 (step S103). By placing the seat back 1 in an upright state, the occupant H can be notified of an abnormality in the protruding mechanism 31. At this time, the seat back is rotated using the reclining mechanism 7 at least until the backward tilt angle θ becomes equal to or less than the predetermined angle β. Alternatively, the rearward tilt angle θ at which the seat back 1 is in an upright state may be set as a second predetermined angle β2, and the seat back 1 may be rotated until the rearward tilt angle θ reaches the second predetermined angle β2. After the rearward tilt angle θ of the seat back 1 becomes equal to or smaller than the predetermined angle β, the seat back rotation prohibition process (step S104) is executed.

[0075] If the rearward tilt angle θ is smaller than the predetermined angle β (No in step S102), or after the seatback return process has been performed, the seat control device 50 performs a seatback rotation prohibition process to prohibit the seatback 1 of the vehicle seat S from transitioning to a relaxed state (step S104). Specifically, the seatback 1 is prohibited from being tilted backward by the reclining mechanism 7 and rotated to an angle equal to or greater than the predetermined angle β.

[0076] At this time, if the seat control device 50 receives an abnormality detection signal from the abnormality detection unit 40, it transmits an abnormality detection signal to the vehicle control device 60 indicating that the protruding state cannot be returned to the normal state (step S105).

[0077] The vehicle control device 60 checks whether the driving mode of the vehicle V is an automatic driving mode or a manual driving mode. If the driving mode is an automatic driving mode, the vehicle control device 60 controls the vehicle V to move safely while remaining in the automatic driving mode (safety operation processing). At this time, for example, as the safety operation processing, the vehicle control device 60 controls the vehicle V to decelerate or to move the vehicle V to a safe place. At this time, the vehicle control device 60 may turn on the hazard lights (step S106).

[0078] When the vehicle V is traveling in the automatic driving mode, the vehicle control device 60 may perform a manual driving prohibition process that prohibits switching to the manual driving mode, so that the driver cannot drive the vehicle manually (step S107).

[0079] Next, the seat control device 50 notifies the seated occupant H that an abnormality in the headrest 3 has been detected, and that the seatback 1 has been returned to the upright position, seatback rotation prohibition processing has been performed, and safety operation processing is being performed in automatic driving mode (step S108). By notifying the occupant H, the occupant H can know the reason why the seatback 1 has been returned to the upright position and safety operation processing is being performed, and the seat control device 50 can give the occupant H a sense of security.

[0080] This notification to the occupant H may be performed using the displays 38L, 38R, which are video display means provided in the vehicle seat S. A message indicating that the protruding mechanism 31 has failed is displayed on the displays 38L, 38R. This notification may also be made using speakers 39L, 39R, which are sound generating means provided in the vehicle seat S. A sound indicating that the protruding mechanism 31 has failed is emitted from the speakers. At this time, the seat control device 50 may notify the user by using an alarm sound or the like. Alternatively, the notification may be made by a vibrator 11, which is a vibration generating means provided in the vehicle seat S. If light emitting devices 42, which are illumination means, are provided on the left side 33L and right side 33R of the headrest 3 instead of the displays 38L and 38R, the notification may be made by the light emitting devices 42. Alternatively, the seat control device 50 may make a notification by combining these.

[0081] The notification to the occupant may be made not only using a display or the like provided in the vehicle seat S, but also using a monitor 68A or the like provided in the vehicle V. This notification is made by the vehicle control device 60 after the vehicle control device 60 receives an abnormality detection signal from the seat control device 50. The vehicle control device 60 makes the notification using at least one of the monitor 68A, speaker 68B, lighting device 68C, vibration device 68D, or the like provided in the vehicle V. This notification may be made using a combination of the monitor 68A, speaker 68B, lighting device 68C, and vibration device 68D.

[0082] In the above embodiment, when the side portion of the headrest 3 cannot be returned from the protruding state to the normal state, the vehicle V is put into automatic driving mode to automatically make a safe movement of the vehicle V. However, this is just one example, and there is also a case where the occupant H desires manual driving during automatic driving mode and the manual driving mode is selected. In this case, as a second safety operation process for putting the vehicle V into manual driving mode and making a safe operation, the seat control device 50 or the vehicle control device 60 of the vehicle V may automatically notify a dealer or the like that a malfunction has occurred in the headrest. In this way, when an abnormality in the headrest is detected, the seat control device 50 makes the vehicle V make a safe operation via the vehicle control device 60, thereby ensuring the safety of the occupants. [Explanation of symbols]

[0083] V vehicle H Crew F body floor D-door S Vehicle seat (vehicle seat) T Cushion trim cover (surface) P Pad Sh seat body 1 seat back 1a Support surface 11 Vibrator (vibration generating means) 2 seat cushions 2a Seating surface 21 Slide rail 22 Seatbelt device 3 Headrest 31 Ejection mechanism 32 Main Section 32a Headrest pillar 33L Left side (side) 33R Right side (side) 34 Main contact surface 35L hinge 35R hinge 36L Left contact surface 36R Right contact surface 37L left drive unit 37R Right drive unit 38L Left display (video display means) 38R Right display (video display means) 39L Left speaker (audio generating means) 39R Right speaker (sound generating means) 40 Abnormality detection unit 41 Optical Sensor 42 Light-emitting device (lighting means) 50 Seat control device (control unit) 51 CPU 52 ROM 53 RAM 54 Communication Interface 55 Bus 60 Vehicle control device (vehicle control unit) 61 CPU 62 ROM 63 RAM 64 Communication Interface 65 Bus 66 Operation mode switching section 67 Automatic driving control unit 68A Monitor (video display means) 68B Speaker (sound generating means) 68C Lighting device (lighting means) 68D Vibration device (vibration generating means) 7 Reclining mechanism 71 Reclining rod 72 Guide 73 Reclining drive unit 74 Reclining angle detector 81 Roof side rail 82 Curtain airbag 83 Front airbag

Claims

1. A vehicle seat provided in a vehicle, Seat cushion and a seat back rotatably attached to the seat cushion; a reclining mechanism that supports the seat back so that the angle of the seat back can be adjusted relative to the seat cushion; a headrest provided at an upper end of the seat back and having a protruding mechanism whose side portions protrude forward; an abnormality detection unit that detects an abnormality in the protrusion mechanism; a control unit that controls the operation of the reclining mechanism and the protruding mechanism, When the abnormality detection unit detects an abnormality in the protruding mechanism, if the rearward tilt angle of the seat back exceeds a predetermined angle with respect to the vertical direction, the control unit performs a seat back return process to rotate the seat back using the reclining mechanism until the rearward tilt angle of the seat back reaches the predetermined angle, and if the rearward tilt angle of the seat back is equal to or less than the predetermined angle, the control unit performs a seat back rotation prohibition process to prohibit the seat back from rotating using the reclining mechanism.

2. The side portions protruding forward are provided on the left and right sides of the headrest, 2. The vehicle seat according to claim 1, wherein the abnormality in the protrusion mechanism is that at least one of the left and right side portions cannot be protruded forward.

3. The side portions protruding forward are provided on the left and right sides of the headrest, 2. The vehicle seat according to claim 1, wherein the abnormality in the protrusion mechanism is that at least one of the left and right side portions closest to the window of the vehicle cannot be protruded.

4. A vehicle seat as described in any one of claims 1 to 3, characterized in that when the abnormality detection unit detects the abnormality in the protrusion mechanism, the control unit sends an abnormality detection signal to a vehicle control unit that controls the vehicle, indicating that the abnormality in the protrusion mechanism has occurred.

5. The vehicle seat according to claim 4, characterized in that, when the abnormality detection unit detects the abnormality in the protruding mechanism, the control unit notifies the occupant of the vehicle via the vehicle control unit or directly that the seat back return process or the seat back rotation prohibition process is being performed due to the detection of the abnormality in the protruding mechanism.

6. 6. The vehicle seat according to claim 5, wherein the notification is performed using at least one of a sound generating means, a video display means, a lighting means, and a vibration generating means provided in the vehicle or the vehicle seat.

7. The vehicle control unit can switch the vehicle between an automatic driving mode and a manual driving mode, A vehicle seat as described in any one of claims 4 to 6, characterized in that when the abnormality detection unit detects the abnormality in the protrusion mechanism, and when the vehicle is in the automatic driving mode, the control unit sends a mode switching signal to the vehicle control unit to switch from the automatic driving mode to the manual driving mode.

8. The vehicle control unit can switch the vehicle between an automatic driving mode and a manual driving mode, A vehicle seat as described in any one of claims 4 to 6, characterized in that when the abnormality detection unit detects the abnormality in the protrusion mechanism, it sends an automatic driving prohibition signal to the vehicle control unit to prohibit the vehicle from transitioning to the automatic driving mode.

9. The side portions protruding forward are provided on the left and right sides of the headrest, the abnormality of the protrusion mechanism is that at least one of the side portions provided on the left and right sides cannot return from a protruding state to a normal state, The vehicle seat according to claim 1, characterized in that, when the abnormality detection unit detects the abnormality in the protrusion mechanism, the control unit transmits an abnormality detection signal to a vehicle control unit that controls the vehicle, indicating that the abnormality in the protrusion mechanism has occurred.

10. The vehicle control unit can switch the vehicle between an automatic driving mode and a manual driving mode, The vehicle seat of claim 9, characterized in that when the abnormality detection unit detects the abnormality in the protrusion mechanism, if the vehicle is in manual driving mode, the control unit switches the vehicle to the automatic driving mode using the vehicle control unit and performs safety operation processing to cause the vehicle to move safely.

11. The vehicle seat according to claim 10, wherein the control unit prohibits the vehicle control unit from switching to the manual driving mode.

12. The vehicle seat according to claim 10 or 11, characterized in that the control unit notifies an occupant of the vehicle, via the vehicle control unit or directly, that the safety operation processing is being performed because the abnormality in the protrusion mechanism has been detected.

13. 13. The vehicle seat according to claim 12, wherein the notification is performed using at least one of a sound generating means, a video display means, a lighting means, and a vibration generating means provided in the vehicle or the vehicle seat.

14. The vehicle control unit can switch the vehicle between an automatic driving mode and a manual driving mode, The vehicle seat of claim 9, characterized in that when the abnormality detection unit detects an abnormality in the protrusion mechanism, and when the vehicle is in the automatic driving mode and a manual driving mode is selected by an occupant of the vehicle, the control unit performs a second safety operation process by switching the vehicle to the manual driving mode via the vehicle control unit, causing the vehicle to move safely.

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