Vehicle seats

Abstract

To provide a vehicle seat that is suppressed in feeling of bottoming-out even when thickness of a cushion pad is reduced.SOLUTION: A vehicle seat 1 includes: a cushion frame 20 constituting a skeleton of a seat cushion 10; and S springs 30 hooked across the cushion frame 20 and receiving load acting on a seating face of the seat cushion 10 via a cushion pad 11. The seat cushion 10 and the S springs 30 are set so that a ratio between a deflection amount of the S springs 30 and a deflection amount of the cushion pad 11 becomes 35:65 to 70:30 when a load of 490 N is added to the seat cushion 10.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle seat. [Background Art]

[0002] It is known to provide a thinned cushion pad in a seat cushion of a vehicle seat (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a seat cushion for a vehicle seat, comprising: a seat cushion pad in which a pad thickness at a hip point is set to about 80 mm; and a skin locking wire made of a rigid material such as metal embedded along a skin locking groove formed in the seat cushion pad. [Prior Art Literature] [Patent Literature]

[0004] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2006-166987 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] Incidentally, in a vehicle seat, even when the cushion pad is thinned, it is preferable to suppress a bottoming-out sensation.

[0006] An object of the present invention is to obtain a vehicle seat in which a bottoming-out sensation is suppressed even when the cushion pad is thinned. [Means for Solving the Problem]

[0007] Regarding the first aspect The vehicle seat comprises: a cushion frame that constitutes a framework of a seat cushion; and an elastic member that is bridged over the cushion frame and receives a load acting on a seating surface of the seat cushion via a cushion pad, The thickness below the hip point is between 20mm and 55mm. the seat cushion At the center of the main section, 150mm forward from the point where it meets the seatback. When a load of 490N is applied, the ratio of the deflection of the elastic member to the deflection of the cushion pad is, 42:58~51:49 The seat cushion and the elastic member are set up in such a manner.

[0008] According to the first aspect of the present invention According to vehicle seats, seat cushion At the center of the main section, 150mm forward from the point where it meets the seatback. When a load of 490N is applied, the ratio of the deflection of the elastic member to the deflection of the cushion pad is, 42:58~51:49 The seat cushion and elastic members are set up in such a way that the cushion pad can be made thinner. (The thickness of the seat cushion below the hip point is between 20mm and 55mm.) Even in such cases, the elastic material provides an appropriate amount of deflection. Therefore, even when the cushion pad is made thinner, the hip point can be positioned as intended when the occupant is seated in the vehicle seat.

[0009] Furthermore, when an occupant sits in the vehicle seat, the elastic modulus of the elastic material can be appropriately adjusted to prevent the elastic material from becoming too hard. As a result, even when the cushion pad is made thinner, the feeling of bottoming out can be suppressed.

[0010] Furthermore, the contribution of elastic materials during normal seating by occupants in vehicle seats can be suppressed. Therefore, vibration absorption can be improved even when the cushion pad is made thinner.

[0011] As a result, even when the cushion pad is made thinner, it is possible to suppress the feeling of bottoming out while ensuring vibration absorption by the elastic material.

[0014] A second aspect of the present invention For vehicle seats, First aspect In the vehicle seat described above, the elastic member is a set of three S-springs, each having a bent portion that is curved in the width direction of the seat.

[0015] The elastic member is three S-shaped springs each having a bent portion bent in the seat width direction, so that the wire diameter of the S-shaped springs can be set larger than in a case where four S-shaped springs are provided. Therefore, the durability of each S-shaped spring can be improved.

[0016] A third aspect of the present invention In a vehicle seat, First aspect or second aspect In the vehicle seat according to , the 25% hardness of the main portion of the cushion pad is 180 to 270 N.

[0017] A third aspect of the present invention According to the vehicle seat, when the 25% hardness of the main portion of the cushion pad is set to 180 to 270 N, bottoming-out of the cushion pad is suppressed when an occupant sits on the seat cushion. Therefore, it is possible to suppress an occupant sitting on the seat cushion from feeling a sensation of a foreign object.

Effects of the Invention

[0018] According to the vehicle seat of the present invention, a feeling of bottoming-out can be suppressed even when the cushion pad is thinned.

Brief Description of Drawings

[0019] [Figure 1] FIG. 1 is a perspective view of the vehicle seat according to the present embodiment as viewed from diagonally forward left of the seat. [Figure 2] FIG. 2 is a perspective view of the seat cushion according to the present embodiment as viewed from diagonally forward left of the seat. [Figure 3] FIG. 3 is a cross-sectional view showing a state where an occupant sits on the vehicle seat according to the present embodiment, and shows the A-A cross-section in FIG. 2. [Figure 4] FIG. 4 is an FS diagram showing the relationship between load and deflection for a standard-type vehicle seat. [Figure 5] FIG. 5 is an FS diagram showing the relationship between load and deflection for a thin-type vehicle seat.

Mode for Carrying Out the Invention

[0020] The vehicle seat according to this embodiment will be described below with reference to the drawings. In this embodiment, an example will be described in which the vehicle seat is the front seat of the vehicle. Arrows FR shown as appropriate in each figure indicate the front of the seat in the front-rear direction, arrow UP indicates the top of the seat in the up-down direction, and arrow LH indicates the left of the seat in the width direction. In this embodiment, the front of the vehicle is considered the front of the seat. The hip point HP is the center of the occupant's buttocks (design value) and refers to the rotational center point connecting the torso and thigh of a three-dimensional mannequin according to the American SAE standard J-826 (SAE-3DM type).

[0021] [Vehicle seat configuration] As shown in Figure 1, the vehicle seat 1 comprises a seat back 2 that supports the occupant's upper body, a headrest 4 provided on the upper side of the seat back 2 to support the occupant's head, and a seat cushion 10 on which the occupant sits.

[0022] As shown in Figure 2, the seat cushion 10 comprises a cushion frame 20, an S-spring 30 as an elastic member, and a cushion pad 11.

[0023] (Cushion frame 20) The cushion frame 20 constitutes the framework of the seat cushion 10. The cushion frame 20 comprises a front frame 22, a rear frame 24, and side frames 26.

[0024] The side frames 26 are arranged in pairs on the left and right sides, spaced apart in the width direction of the seat. The side frames 26 extend in the front-to-back direction of the seat and are formed in a plate shape with the width direction of the seat as the thickness direction.

[0025] The front frame 22 extends in the width direction of the sheet and is formed in a plate shape with the thickness direction approximately equal to the vertical direction of the sheet. The front frame 22 connects the front sides of the pair of left and right side frames 26. The front frame 22 has three through holes 22A that penetrate in the thickness direction.

[0026] The rear frame 24 is formed in a cylindrical shape that extends in the seat width direction. The rear frame 24 connects the left and right pair of side frames 26 to the rear of the seat.

[0027] As shown in Figure 1, a pair of left and right slide rails 16 are provided on the lower sides of both ends of the cushion frame 20 in the seat width direction, extending along the seat's front-to-back direction. The slide rails 16 are fixed to the vehicle floor 8. The vehicle seat 1 is slidable along the seat's front-to-back direction via the slide rails 16.

[0028] (Cushion pad 11) As shown in Figure 2, the cushion pad 11 is formed from a foam material such as a urethane pad. The cushion pad 11 comprises a main portion 12 and a side support portion 14.

[0029] As shown in Figures 2 and 3, the main section 12 is located in the center of the seat width direction and supports the buttocks and thighs of the occupant M when the occupant M is seated. The side support sections 14 are provided on both sides of the main section 12 in the seat width direction, protruding above the main section 12.

[0030] The cushion pad 11 is used in a thin-type seat cushion 10, and the thickness T of the main portion 12 below the hip point HP can be between 20 mm and 55 mm. The lower limit thickness T of the main portion 12 of the thin-type seat cushion 10 can be any thickness that meets the manufacturing requirements. Furthermore, the thickness T of the main portion 12 below the hip point HP of the cushion pad 11 does not include any grooves or protrusions formed in the cushion pad. The cushion pad 11 is supported by an S-spring 30.

[0031] (S spring 30) As shown in Figure 2, the S-springs 30 are arranged in the front-to-back direction of the seat and attached to the cushion frame 20 in three places. The S-springs 30 are configured to receive the load acting on the seat surface of the seat cushion 10 via the cushion pad 11.

[0032] The S-spring 30 is formed by bending a rod-shaped steel material. Three S-springs 30 are arranged side by side in the width direction of the seat. The tip of the S-spring 30 is hook-shaped and is hooked into the through hole 22A of the front frame 22 via a resin protective cover. The rear end of the S-spring 30 is also hook-shaped and is hooked into the rear frame 24.

[0033] The S-spring 30 has a bent portion 38 that is bent and extends in a roughly U-shape in the width direction of the sheet. The S-spring 30 may also be provided with connecting members that connect the S-springs 30 to each other.

[0034] [Seat cushion 10 operation] As shown in Figure 3, when an occupant M sits on the vehicle seat 1, the load directed downwards on the seat is distributed and acted upon the cushion pad 11 and the S-spring 30. When the load directed downwards on the seat acts upon the cushion pad 11 and the S-spring 30, the cushion pad 11 deforms in the vertical direction of the seat, and the S-spring 30 deforms so as to bend downwards on the seat.

[0035] [Relationship between the deflection of the S-spring and the deflection of the cushion pad] In vehicle seats, it was found that thinning the cushion pad worsened the feeling of bottoming out. Furthermore, it was found that lowering the elastic modulus of the S-spring suppressed the worsening of bottoming out, but reduced vibration absorption performance, resulting in a deterioration of ride comfort. Therefore, the following tests were conducted to determine the optimal relationship between the S-spring deflection and the cushion pad deflection that best meets the required performance criteria of suppressing bottoming out while ensuring vibration absorption.

[0036] (Deflection test for a standard type seat cushion) First, a deflection test was conducted on a standard type seat cushion. For the deflection test on the standard type seat cushion, five mass-produced seat cushions 510-514 were prepared and tested.

[0037] In the deflection test, a load (JSAE Cu PAN) was used to pre-pressure up to 100 kgf at a rate of 300 mm / min, followed by unloading. This process was repeated twice. One minute after the pre-pressure was completed, the load was applied again at a rate of 300 mm / min, and the deflection of the entire seat cushion was measured from the amount of displacement of the load when a 490 N load was applied.

[0038] During the deflection measurement, a displacement meter such as a laser displacement meter was set in the loaded area, below the S-spring, to measure the deflection of the S-spring under load. The ratio of the deflection of the cushion pad to the deflection of the S-spring was calculated from the total deflection of the seat cushion and the deflection of the S-spring.

[0039] Regarding the load position, in the seat width direction, it was centered on the main part of the cushion pad, and in the seat front-to-back direction, it was centered 150 mm in front of the seat, relative to the surface of the seat back where it meets the seat cushion.

[0040] [Table 1]

[0041] As shown in Table 1, seat cushion 510 has a cushion pad thickness of 82.8 mm below the hip point HP, while seat cushion 511 has a cushion pad thickness of 60.6 mm below the hip point HP.

[0042] As a result of the tests, as shown in Figure 4, it was found that for the standard type seat cushions 510 to 514, the FS diagram showing the relationship between load and deflection falls within a predetermined range S.

[0043] (Deflection test for thin-type seat cushions) Next, a deflection test was conducted on a thin-type seat cushion. In the deflection test for the thin-type seat cushion, the relationship between the deflection of the S spring and the deflection of the cushion pad, in relation to the deflection of the seat cushion, was determined so that it fell within the predetermined range S of the FS diagram derived in the deflection test for the standard-type seat cushion.

[0044] [Table 2]

[0045] As shown in Table 2, two types of thin seat cushions were prepared: seat cushion 110 with a cushion pad thickness of 50 mm below the hip point (HP), and seat cushion 111 with a cushion pad thickness of 40 mm below the hip point (HP).

[0046] As shown in Figure 5, for the thin-type seat cushions 110 and 111, the amount of deflection of the S-spring and the amount of deflection of the cushion pad were set in relation to the amount of deflection of the seat cushion so that the FS diagram would be approximately the same as that derived from the deflection test for the standard-type seat cushions 510 and 511. In other words, for the thin-type seat cushions 110 and 111, the amount of deflection of the S-spring and the amount of deflection of the cushion pad were set in relation to the amount of deflection of the seat cushion so that it would fall within a predetermined range S of the FS diagram derived from the deflection test for the standard-type seat cushions 510 to 514.

[0047] As a result of a series of tests, as shown in Table 2, in the seat cushion 110, the amount of deflection of the S spring relative to the amount of deflection of the seat cushion and the amount of deflection of the cushion pad were set such that when a load of 490N was applied to the seat cushion 110, the ratio of the amount of deflection of the S spring to the amount of deflection of the cushion pad was 42:58.

[0048] In the seat cushion 111, the amount of deflection of the S spring relative to the amount of deflection of the seat cushion and the amount of deflection of the cushion pad relative to the amount of deflection of the seat cushion were set such that when a load of 490N is applied to the seat cushion 111, the ratio of the amount of deflection of the S spring to the amount of deflection of the cushion pad is 51:49.

[0049] In other words, when a load of 490N is applied to the seat cushion 10, it was confirmed that by setting the amount of deflection of the S spring 30 relative to the amount of deflection of the seat cushion 10, and the amount of deflection of the cushion pad 11 relative to the amount of deflection of the seat cushion 10, so that the ratio of the amount of deflection of the S spring 30 to the amount of deflection of the cushion pad 11 is approximately half, the seat cushion 10 can exhibit deflection performance equivalent to that of a normal type seat cushion.

[0050] Incidentally, especially with thin-type seat cushions, if the deflection of the S-spring 30 falls below 35% of the total deflection of the seat cushion 10, the amount of deflection will be insufficient when occupant M sits on the vehicle seat 1. As a result, the hip point HP will rise in the vertical direction of the vehicle. Also, if the deflection of the S-spring 30 falls below 35% of the total deflection of the seat cushion 10, the elastic modulus of the S-spring 30 will increase, making the S-spring 30 stiffer. As a result, occupant M will feel a bottoming-out sensation when sitting on the vehicle seat.

[0051] On the other hand, if the deflection of the S-spring 30 exceeds 70% of the total deflection of the seat cushion 10, the contribution of the S-spring 30 to the normal seating of occupant M on the vehicle seat 1 becomes large. As a result, the vibration absorption when occupant M is seated on the vehicle seat 1 is impaired.

[0052] From this, it was found that when a load of 490N is applied to the seat cushion 10, it is preferable to set the amount of deflection of the S spring 30 relative to the amount of deflection of the seat cushion 10, and the amount of deflection of the cushion pad 11 relative to the amount of deflection of the seat cushion 10, such that the ratio of the amount of deflection of the S spring 30 to the amount of deflection of the cushion pad 11 is 35:65 to 70:30.

[0053] [Relationship between cushion pad hardness] By the way, if the 25% hardness of the main part 12 of the cushion pad 11 is less than 180N, the cushion pad 11 will bottom out when occupant M sits on the seat cushion 10. As a result, occupant M sitting on the seat cushion 10 will feel a foreign object sensation.

[0054] On the other hand, if the 25% hardness of the main part 12 of the cushion pad 11 exceeds 270N, the reaction force from the cushion pad 11 when occupant M sits on the seat cushion 10 becomes too strong. As a result, occupant M sitting on the seat cushion 10 may feel uncomfortable.

[0055] Furthermore, if the cushion pad 11 is thin, or if the cushion pad 11 is too hard, the buttocks and thighs will not sink into the cushion pad 11. As a result, the occupant M sitting on the seat cushion 10 will feel unstable.

[0056] From this, it was found that the 25% hardness of the main part of the cushion pad is preferably 180-270N.

[0057] [Effect] The vehicle seat 1 of this embodiment includes a cushion frame 20 that constitutes the framework of the seat cushion 10, and an S-spring 30 that spans the cushion frame 20 and receives the load acting on the seat surface of the seat cushion 10 via a cushion pad 11. The seat cushion 10 and the S-spring 30 are set such that when a load of 490N is applied to the seat cushion 10, the ratio of the deflection of the S-spring 30 to the deflection of the cushion pad 11 is 35:65 to 70:30.

[0058] When a load of 490N is applied to the seat cushion 10, the ratio of the deflection amount of the S-spring 30 to the deflection amount of the cushion pad 11 is set to 35:65 to 70:30. This ensures that even when the cushion pad 11 is made thinner, the S-spring 30 provides an appropriate amount of deflection. Therefore, even when the cushion pad 11 is made thinner, the hip point HP can be positioned to the desired location when the occupant M is seated in the vehicle seat 1.

[0059] Furthermore, when occupant M sits on the vehicle seat 1, the elastic modulus of the S spring 30 can be appropriately adjusted to prevent the S spring 30 from becoming too stiff. As a result, even if the cushion pad 11 is made thinner, a seat cushion 10 can be made that does not feel like it is bottoming out.

[0060] Furthermore, the contribution of the S spring 30 during normal seating of occupant M on the vehicle seat 1 can be suppressed. Therefore, even when the cushion pad 11 is made thinner, vibration absorption can be improved.

[0061] As a result, even when the cushion pad 11 is made thinner, it is possible to create a vehicle seat 1 that does not feel like it is bottoming out, while still ensuring vibration absorption by the S spring 30.

[0062] In the vehicle seat 1 of this embodiment, the thickness T of the cushion pad 11 below the hip point HP is 55 mm or less.

[0063] The thickness T of the cushion pad 11 below the hip point HP is 55 mm or less, which allows for a thinner seat cushion 10. Furthermore, when a load of 490 N is applied to the seat cushion 10, the ratio of the deflection of the S spring 30 to the deflection of the cushion pad 11 is set to 35:65 to 70:30. This ensures that even with a thinner cushion pad 11, the vibration absorption provided by the S spring 30 is maintained, resulting in a vehicle seat 1 that does not feel like it is bottoming out.

[0064] In the vehicle seat 1 of this embodiment, the S-spring 30 consists of three S-springs, each having a bent portion 38 that is bent in the seat width direction (see Figure 2).

[0065] The S-spring 30 consists of three S-springs, each having a bent portion 38 that is bent in the width direction of the sheet. Compared to a case where four S-springs 30 are used, the wire diameter (thickness) of the S-springs 30 can be set to be larger. Therefore, the durability of each S-spring 30 can be improved.

[0066] Furthermore, since the S-spring 30 consists of three S-springs 30, each having a bent portion 38 that is bent in the seat width direction, the amount of S-springs 30 used is reduced compared to the case where four S-springs 30 are provided. As a result, the weight of the vehicle seat 1 can be reduced.

[0067] In the vehicle seat 1 of this embodiment, the 25% hardness of the main part 12 of the cushion pad 11 is 180 to 270 N.

[0068] The 25% hardness of the main part 12 of the cushion pad 11 is 180-270N, which prevents the cushion pad 11 from bottoming out when the occupant M sits on the seat cushion 10. Therefore, it is possible to prevent the occupant M sitting on the seat cushion 10 from feeling any foreign body sensation.

[0069] Furthermore, the 25% hardness of the main part 12 of the cushion pad 11 is 180-270N, which ensures that the reaction force from the cushion pad 11 is appropriate when an occupant M sits on the seat cushion 10. Therefore, it is possible to prevent the occupant M from feeling uncomfortable when sitting on the seat cushion 10.

[0070] Furthermore, since the 25% hardness of the main part 12 of the cushion pad 11 is 180-270N, even when the cushion pad 11 is thin, the 25% hardness of the cushion pad 11 is appropriate, allowing the buttocks and thighs to sink into the cushion pad 11 appropriately. As a result, the feeling of instability for the occupant M seated on the seat cushion 10 can be eliminated.

[0071] The vehicle seat of the present invention has been described above based on the above embodiments. However, the specific configuration is not limited to these embodiments, and changes to the design are permitted as long as they do not deviate from the gist of the invention as described in each claim of the patent.

[0072] In the above embodiment, an example was shown in which three S-springs 30, which serve as elastic members, are provided in the seat cushion 10. However, the number of S-springs provided in the seat cushion is not limited to this embodiment.

[0073] In the above embodiment, an example was shown in which the elastic member is an S-spring 30. However, other types of springs can be used as the elastic member.

[0074] In the above embodiment, an example was shown in which the S-spring 30 is stretched across the seat in the front-rear direction. However, the S-spring may also be stretched across the seat in the width direction.

[0075] The above embodiment shows an example in which the vehicle seat 1 is applied to the front seat of a vehicle. However, the vehicle seat can also be applied to the rear seat of a vehicle. [Explanation of Symbols]

[0076] 1. Vehicle seat 10 Seat Cushions 11 Cushion pads 12 Main section 20 Cushion Frames 30 S-spring (an example of an elastic member) 38. Bending section HP Hip Point

Claims

1. The cushion frame that makes up the framework of the seat cushion, The cushion frame is spanned by an elastic member that receives the load acting on the seat surface of the seat cushion via a cushion pad, The seat cushion and the elastic member are configured such that, when a load of 490N is applied to the center of the main part of the seat cushion, which has a thickness of 20 mm to 55 mm below the hip point, at a position 150 mm forward from the joint with the seat back, the ratio of the deflection of the elastic member to the deflection of the cushion pad is 42:58 to 51:

49. Vehicle seats.

2. The elastic member is a set of three S-springs, each having a bent portion that curves in the width direction of the sheet. A vehicle seat according to claim 1.

3. The 25% hardness of the main part of the cushion pad is 180 to 270 N. A vehicle seat according to claim 1.

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