Vehicle seat

[0035] in figure 1 , The main part of the vehicle seat 10 according to the embodiment of the present invention is shown in a perspective view viewed from the front left of the vehicle. figure 2 Here, the main part of the vehicle seat 10 is shown in a side view viewed from the left side of the vehicle. In the drawings, the arrow FR indicates the front of the vehicle, the arrow RH indicates the right side of the vehicle (the side in the vehicle width direction), and the arrow UP indicates the upper side.

[0036] As shown in the above figure, the vehicle seat 10 includes a seat back 12. The seat back 12 is configured to be arranged in a state of being erected at the rear end of the seat cushion (not shown) constituting the vehicle seat 10 and capable of holding the upper body of the occupant.

[0037] In the seat back 12, a seat back frame 14 is provided, and the seat back frame 14 is connected to a cushion frame (not shown) provided in the seat cushion. The seat back frame 14 includes a pair of side frames 16 that are bent into a substantially U-shaped cross section ( figure 1 Only the side frame 16 on the left side of the vehicle is shown in ). Above the side frame 16, a long tubular upper frame 18 is provided. The upper frame 18 is bent into an approximately inverted U shape when viewed from the front of the vehicle, and both ends of the upper frame 18 are fixed to a pair of side frames 16 respectively.

[0038] A pair of brackets 20 made of metal (in a broad sense, elements understood as "mounting portions") are provided on the middle portion of the upper frame 18 in the longitudinal direction at a position in front of the vehicle, and the bracket 20 passes It is fixed to the upper frame 18 by welding. The bracket 20 is formed in an approximately rectangular tube shape and is arranged in the vertical direction.

[0039] Same as image 3 As shown, in the cylinders of the pair of brackets 20, there is provided a substantially rectangular cylinder-shaped grommet 22 formed of resin as a supporting mechanism and a holding member. At the upper end of the backing ring 22, an approximately rectangular plate-shaped head 24 is provided, and at the lower end of the backing ring 22, a blocking portion 25 having an approximately quadrangular pyramid shape is provided. The backing ring 22 is held in the bracket 20 in a state where the head 24 abuts against the upper end of the bracket 20 and the blocking portion 25 abuts against the lower end of the bracket 20.

[0040] Same as Figure 4 As shown, in the vehicle front portion of the backing ring 22 and at the position of the middle portion in the longitudinal direction, a convex portion 26 is integrally provided as a front side restricting portion. The convex portion 26 is formed in a substantially rectangular shape when viewed from the front of the vehicle, and protrudes from the backing ring 22 toward the front of the vehicle, and abuts against the inner peripheral portion of the bracket 20. Thereby, the convex portion 26 is bound to the bracket 20 (the seat back frame 14 ), and the vehicle front portion of the backing ring 22 is supported by the bracket 20 at one convex portion 26 location.

[0041] A pair of convex portions 28 as rear side restraining portions are provided at the vehicle rear portion of the backing ring 22 at both ends in the longitudinal direction, whereby the upper convex portion 28 is arranged above the convex portion 26 . The pair of convex portions 28 are formed in a substantially rectangular shape when viewed from the rear of the vehicle, and project from the backing ring 22 toward the rear of the vehicle, and abut against the inner peripheral portion of the bracket 20. Thereby, the convex portion 28 is tied to the bracket 20 (the seat back frame 14 ), and the vehicle rear portion of the backing ring 22 is supported by the bracket 20 at two convex portions 28.

[0042] In the backing ring 22, an insertion hole 30 (refer to image 3 ). The insertion hole 30 is formed to have a circular cross-section, and the pillar 46 of the headrest 40 described below is inserted into the insertion hole 30.

[0043] Above the seat back 12, a headrest 40 is provided. The headrest 40 has a filling part 42 formed of a polyurethane foam material, and the filling part 42 is covered by a cover 44. In the filling portion 42, a pillar 46 having a round rod shape as a support mechanism and a support member is provided. The pillar 46 is formed in an approximately inverted U shape when viewed from the front of the vehicle, and is bent so that both ends in the longitudinal direction are arranged toward the front of the vehicle when viewed from the left of the vehicle. In addition, the longitudinal middle portion of the pillar 46 is fixed to the filling portion 42, and the longitudinal ends of the pillar 46 protrude downward from the headrest 40 and are inserted into the insertion hole 30 of the backing ring 22. In addition, a lock mechanism (not shown) provided on the head 24 of the backing ring 22 prevents the pillar 46 from moving relative to the vertical direction. Thus, the headrest 40 is configured to be supported by the support 20 (chair Back frame 14) to support the head H of the occupant.

[0044] Here, as described above, the vehicle front portion of the backing ring 22 is supported by the bracket 20 at one convex portion 26, and the convex portion 26 restricts the backing ring 22 from bending toward the front of the vehicle. The vehicle rear portion of the backing ring 22 is supported by the bracket 20 at two convex portions 28, and the upper convex portion 28 restricts the backing ring 22 from bending toward the rear of the vehicle. Furthermore, since the upper convex portion 28 is arranged on the headrest 40 side with respect to the convex portion 26, the distance from the headrest 40 to the convex portion 26 is set to be longer than the distance from the headrest 40 to the upper convex portion 28. Therefore, the headrest 40 is supported by the bracket 20 (seat back frame) so that the flexural rigidity of the pillar 46 including the backing ring 22 toward the front of the vehicle is smaller than the flexural rigidity of the pillar 46 including the backing ring 22 toward the rear of the vehicle. 14).

[0045] In addition, the backing ring 22 is held by the bracket 20, and when an impact force is applied to the seat back 12 when the vehicle collides back, the impact force is input to the backing ring 22 through the seat back frame 14 and the bracket 20. As a result, the headrest 40 and the support column 46 vibrate in the front and rear directions of the vehicle using the convex portion 26 and the upper convex portion 28 of the backing ring 22 as fulcrums, so that the headrest 40 is displaced in the front and rear direction of the vehicle based on the seat back frame 14 . In addition, since the flexural rigidity of the pillar 46 (including the backing ring 22) toward the front of the vehicle is smaller than the flexural rigidity of the pillar 46 (including the backing ring 22) toward the rear of the vehicle, it is set such that when the headrest 40 vibrates, the headrest The amplitude of 40 toward the front of the vehicle is greater than the amplitude of toward the rear of the vehicle, and the period of the headrest 40 toward the front of the vehicle is longer than the period toward the rear of the vehicle.

[0046] In addition, the time until the head H of the occupant touches the headrest 40 after the vehicle collides with the vehicle (this time is referred to as the "contact time") is the time after the vehicle collides with the headrest 40 until the displacement of the headrest 40 to the front of the vehicle becomes the maximum. The method of time (this time is referred to as “peak time”) adjusts the bending rigidity of the strut 46 including the backing ring 22. That is, since the speed of the headrest 40 toward the front of the vehicle during the peak time decreases and becomes zero, the contact time is set to be the time when the speed of the headrest 40 toward the front of the vehicle is below a predetermined reference value (this time is referred to as The “reference time”) adjusts the bending rigidity of the pillar 46 including the backing ring 22 in the following manner.

[0047] Here, in the vehicle seat 10 according to the present embodiment, the following function is formed, and the function is described by comparing the function with the conventional technology described below.

[0048] When the vehicle collides backward, the seat back frame 14 is applied with an impact force to the front of the vehicle. Therefore, the impact force is input to the backing ring 22 via the seat back frame 14 and the bracket 20, and the upper frame 18 (the seat back frame 14) of the headrest 40 vibrates as a reference.

[0049] use Figure 5 The operation of the headrest 40 at this time will be described. among them, Figure 5 This is the amount of displacement of the headrest 40 with respect to the above frame 18 as a reference to the time when the vehicle collides from behind. As that Figure 5 As shown by the solid line, when the vehicle collides backward, the upper frame 18 (seat back frame 14) is inputted with the impact force from the front of the vehicle, so that the headrest 40 is temporarily displaced to the rear of the vehicle relative to the upper frame 18 due to inertial force, and then to Displacement in front of the vehicle.

[0050] At this time, since the flexural rigidity of the pillar 46 (including the backing ring 22) toward the front of the vehicle is configured to be lower than the flexural rigidity of the pillar 46 (including the backing ring 22) toward the rear of the vehicle, the headrest 40 is greatly displaced toward the front of the vehicle, and the peak The time is about 60msec.

[0051] In addition, the head H of the occupant moves to the rear of the vehicle due to the inertial force when the vehicle collides back. Furthermore, since the flexural rigidity of the strut 46 (including the backing ring 22) is adjusted so that the contact time becomes the peak time when the vehicle collides behind the vehicle, at the peak of the displacement of the headrest 40 toward the front of the vehicle, the head H and the head Pillow 40 contacts (in Figure 5 , The contact time is indicated by a circular mark). Therefore, since the speed of the headrest 40 toward the front of the vehicle when the head H is in contact with the headrest 40 is zero, a decrease in the speed at which the head H enters the headrest 40 is suppressed.

[0052] On the other hand, in the prior art, such as Image 6 As shown, a pair of convex portions 26 are provided at the position of the backing ring 22 in the front of the vehicle at both ends in the longitudinal direction, and the flexural rigidity of the pillar 46 (including the backing ring 22) toward the rear of the vehicle is set to be the same as The pillar 46 (including the backing ring 22) has the same bending rigidity toward the front of the vehicle, and the headrest 40 is supported by the seat back frame 14. When the prior art vehicle collides behind, such as Figure 5 As shown by the dashed line, the headrest 40 is temporarily displaced to the rear of the vehicle based on the frame 18 above, and then the headrest 40 is displaced to the front of the vehicle. However, in the prior art, the flexural rigidity of the pillar 46 (including the backing ring 22) toward the rear of the vehicle is set to be the same as the flexural rigidity of the pillar 46 (including the backing ring 22) toward the front of the vehicle. Will not move significantly. Therefore, sometimes before the peak time and when the speed of the headrest 40 toward the front of the vehicle is greater than the reference value, the headrest 40 may contact the head H (refer to Figure 5 Circle mark in dotted line).

[0053] Therefore, in the prior art, when the headrest 40 is in contact with the head H, due to the collision of the head H and the headrest 40, the speed of the headrest 40 toward the front of the vehicle is reduced, and the head H enters The headrest 40 slows down (see Figure 7A Inside the box indicated by the dashed line).

[0054] However, the filling portion 42 of the headrest 40 is formed of a polyurethane foam material. Furthermore, in general, the load flexibility curve of the headrest 40 formed of a relatively soft material such as polyurethane is related to the speed at which the head H enters the headrest 40. That is, if the speed at which the head H enters the headrest 40 decreases, the reaction force of the headrest 40 on the head H decreases (refer to Figure 7B Inside the box shown by the dotted line).

[0055] In the balance between the reaction force of the headrest 40 on the head H and the force of the head H on the headrest 40, since the weight of the head H is constant, if the reaction force of the headrest 40 on the head H decreases, Then the acceleration of the head H (hereinafter referred to as "head acceleration") will decrease (refer to Figure 7C Inside the box shown by the dotted line). Thus, the head acceleration of the head H becomes Figure 8 The curve shown.

[0056] Thus, as Picture 9 As shown, in the prior art shown by the dotted line, the head acceleration of the head H sometimes decreases (decreases) when the headrest 40 restrains the head H. However, in the present invention shown by the solid line, the head H is suppressed. Decrease of head acceleration.

[0057] And use Picture 9 The whipping damage index (NIC) of the present invention is compared with the prior art. Among them, in Picture 9 Here, the acceleration of the shoulder of the occupant is represented by a two-dot chain line, the head acceleration of the prior art is represented by a broken line, and the head acceleration of the present invention is represented by a solid line. In the prior art, the difference between the acceleration of the occupant’s shoulders and the head acceleration of the head H is maximum at about 75 msec (refer to Picture 9 Arrow). In the present invention, the difference between the acceleration of the occupant’s shoulders and the head acceleration of the head H is the maximum at about 65 msec (refer to Picture 9 Arrow). As illustrated in this figure, the present invention is smaller than the prior art for the maximum value of the difference between the acceleration of the shoulders of the occupant and the acceleration of the head. However, in the NIC, the smaller the difference between the acceleration of the occupant’s shoulder and the acceleration of the head at any time after the vehicle collides, the smaller the injury value. Therefore, in the present invention, compared with the prior art , Can realize the improvement of NIC.

[0058] As described above, in the vehicle seat 10, the pillar 46 (including the backing ring 22) is set so that the bending rigidity toward the front of the vehicle is smaller than the bending rigidity toward the rear of the vehicle. Therefore, when the seat back 40 is inputted with an impact force and the headrest 40 vibrates when the vehicle collides backward, the headrest 40 is temporarily displaced to the rear of the vehicle due to inertial force, but due to the bending of the pillar 46 (including the backing ring 22) toward the rear of the vehicle Since the rigidity is greater than the bending rigidity toward the front of the vehicle, the headrest 40 reverses in a short time and starts to shift toward the front of the vehicle. In addition, since the bending rigidity of the pillar 46 (including the backing ring 22) toward the front of the vehicle is smaller than the bending rigidity toward the rear of the vehicle, the headrest 40 is largely displaced toward the front of the vehicle. Thereby, the time until the headrest 40 contacts the head H of the occupant can be shortened. Therefore, the headrest 40 can immediately restrain the head H of the occupant who moves to the rear of the vehicle when the vehicle collides with the vehicle. In addition, by setting the bending rigidity of the strut 46 including the backing ring 22, the headrest 40 can be immediately displaced to the head H side of the occupant. Therefore, the headrest 40 can be shortened to contact the head of the occupant with a simple structure. Time until H.

[0059] In addition, in the vehicle seat 10, the contact time until the head H of the occupant comes into contact with the headrest 40 when the vehicle collides behind the vehicle is adjusted so that the peak time until the displacement of the headrest 40 to the front of the vehicle becomes the maximum The bending rigidity of the pillar 46 (including the backing ring 22) is improved. Therefore, it is possible to suppress a decrease in the speed of the head H when the head H of the occupant is in contact with the headrest 40 (when the headrest 40 starts to restrain the head H of the occupant). As a result, the reduction in the speed at which the head H enters the headrest 40 can be suppressed, and the reduction in the head acceleration of the head H when the headrest 40 restrains the head H of the occupant can be suppressed, and the NIC can be improved.

[0060] In addition, in the vehicle seat 10, a convex portion 26 is provided on the vehicle front portion of the backing ring 22 and on the middle portion in the longitudinal direction. The convex portion 26 is provided on the vehicle rear portion of the backing ring 22 and on both ends in the longitudinal direction. , There is a pair of convex portions 28. In addition, the upper convex portion 28 is arranged on the headrest 40 side with respect to the convex portion 26. Therefore, when the headrest 40 is displaced to the rear of the vehicle, the backing ring 22 is supported by the convex portion 28 above, and when the headrest 40 is displaced to the front of the vehicle, the holding member is supported by the convex portion 26. In addition, since the distance from the headrest 40 to the convex portion 26 is longer than the distance from the headrest 40 to the upper convex portion 28, the displacement of the headrest 40 to the front of the vehicle can be made easier than the displacement of the headrest 40 to the rear of the vehicle. Thus, by changing the position of the convex portion 26 in the axial direction (longitudinal direction) of the backing ring 22, the contact time until the headrest 40 contacts the head H of the occupant can be easily set.

[0061] In addition, in the vehicle seat 10, since the convex portion 26 and the convex portion 28 are formed integrally with the backing ring 22, the convex portion 26 and the convex portion 28 can be provided while suppressing an increase in cost.

[0062] In addition, in the vehicle seat 10, since the backing ring 22 is formed of a resin material, by changing the material of the backing ring 22, the bending rigidity of the pillar 46 including the backing ring 22 can be easily adjusted.

[0063] In addition, in the present embodiment, the flexural rigidity of the pillar 46 (including the backing ring 22) is adjusted so that the headrest 40 is brought into contact with the head H of the occupant at the peak of the displacement toward the front of the vehicle, but it may be After the peak time of the displacement of the headrest 40 to the front of the vehicle, the bending rigidity of the pillar 46 (including the backing ring 22) is adjusted so that the headrest 40 is brought into contact with the head H of the occupant. In this case, for example, by changing the position of the convex portion 26 in the longitudinal direction (axial direction) of the backing ring 22, the bending rigidity of the pillar 46 (including the backing ring 22) can be adjusted. Furthermore, even in this case, the contact time of the headrest 40 with the head H of the occupant is after the reference time, and the head H contacts the headrest 40 when the headrest 40 is displaced to the rear of the vehicle. Therefore, when the head H of the occupant is in contact with the headrest 40, the speed at which the head H enters the headrest 40 can be suppressed from decreasing. Thereby, it is possible to suppress a decrease in the acceleration of the head H when the headrest 40 restrains the head H of the occupant during a rear collision.

[0064] In addition, in this embodiment, as described above, the bending rigidity of the pillar 46 (including the backing ring 22) is adjusted so that the headrest 40 is brought into contact with the head H of the occupant at the peak time. Alternatively, the flexural rigidity of the pillar 46 (including the backing ring 22) may be adjusted so that the headrest 40 is brought into contact with the head H of the occupant before the peak time and after the reference time. Even in this case, since the speed of the headrest 40 toward the front of the vehicle when the head H collides with the headrest 40 is below the reference value, it is possible to suppress a decrease in the speed at which the head H enters the headrest 40, and the vehicle The acceleration of the head H when the headrest 40 restrains the head H of the occupant at the time of rear collision decreases.

[0065] In addition, in this embodiment, the backing ring 22 is provided with a convex portion 26 and a convex portion 28. Alternatively, the protrusion 26 and the protrusion 28 may be provided in the holder 20. For example, by bending the bracket 20, the convex portion 26 and the convex portion 28 can be formed.

[0066] In addition, in this embodiment, the convex portion 26 and the convex portion 28 are provided integrally with the backing ring 22. Alternatively, the convex portion 26 and the convex portion 28 and the backing ring 22 may be provided as separate bodies. In this case, by changing the shape and material of the convex portion 26 and the convex portion 28, the bending rigidity of the pillar 46 including the backing ring 22 can be easily adjusted.

[0067] In addition, in the present embodiment, a pair of convex portions 28 are provided at the positions of both ends in the longitudinal direction of the backing ring 22 in the vehicle rear portion. Alternatively, it may be configured such that the convex portion 28 is provided on the entire surface of the backing ring 22 at the rear of the vehicle. In addition, the number of convex portions 18 can be arbitrarily set. That is, it is sufficient to provide at least the convex portion 28 arranged on the headrest 40 side with respect to the convex portion 26.

[0068] In addition, in this embodiment, the pillar 46 of the headrest 40 is configured to be supported by the bracket 20 of the seat back frame 14 via the backing ring 22, but the headrest 40 may be configured to function as a so-called active headrest.