JP6046816B2 - Seat cushion - Google Patents

Description

  The present invention relates to weight reduction of a vehicle seat, and particularly relates to a seat cushion characterized by being highly recyclable and having a good fit and cushioning.

  In general, a seat cushion includes a metal seat frame and a wire, and generally uses urethane foam as a cushioning material and is entirely covered with a skin material. The weight of the occupant is supported mainly by bending the urethane foam layer sandwiched between the seat frame or wire and the skin material in the compression direction, and the cushioning and fitting properties are mainly in the compression direction of the urethane foam layer. It was obtained by the reaction force, the restoring force, and the bending when bent.

  In addition, as a technique related to weight reduction of the seat cushion, Patent Document 1 has a frame shape, and the cross section of the seat frame has a mountain shape, and one side of the mountain shape is formed on the inner peripheral side of the frame shape of the seat frame. The seat frame has an inclined surface facing the seated person, and the seat frame is covered with an elastic net, and its periphery is drawn from the top of the chevron of the seat frame and fixed to the other side of the chevron to make a seat with a concave curved surface A technique has been disclosed in which a stretch is formed so as to form a surface, and an angle is provided between the net and the inclined surface of the seat frame.

  As another technique related to weight reduction, Patent Document 2 discloses a base plate detachably attached to a seat frame, a block disposed on the base plate, a spring plate disposed on the block, and the spring plate. And the block is disposed so as to form a predetermined space between the base plate and the spring plate, and the spring plate is PP (elastic foam). Polypropylene) beads foam, PE (polyethylene) beads foam, PP foam, PE foam, AS resin (acrylonitrile / styrene resin) foam, EVA (ethylene vinyl acetate copolymer resin) and urethane foam material The spring seat is molded from the foam that is formed , Technical relates to a vehicle seat deflected into said space is disclosed when a force to said base plate direction was added.

JP 2002-28044 A Japanese Patent No. 4009490

In conventional general seat cushions, urethane foam is used as a cushioning material, and the cushioning properties are extremely high and the comfort is excellent. However, the urethane foam has a problem that it is inferior in recycling performance. Furthermore, the seat cushion is required to have a function of supporting the occupant's body at an optimum position against the longitudinal and lateral acceleration applied to the occupant as the automobile moves, in addition to the general cushioning property. It is necessary to support the body in an optimal position to reduce fatigue when riding for a long time. For this reason, the function cannot be satisfied with only a very lightweight and flexible urethane foam, and in order to obtain a certain degree of rigidity, the density of the urethane foam needs to be a certain level or more. There was no problem.

In the technology described in Patent Document 1, the net material that supports the load by the occupant is drawn into the seat frame installed around the seat cushion and firmly fixed, and the load applied by the occupant's seating is finally transmitted through the net material. It was supported by the rigidity of the seat frame. Therefore, the structure of the seat frame must maintain a certain level of strength. For this reason, although the weight of the net material itself corresponding to the conventional cushion material is light, the weight of the seat frame tends to increase and the overall weight There was a problem that the reduction effect was not sufficient.

Furthermore, the cushioning property of the net material is limited because it is obtained mainly by the elongation of the material, and there is a tendency that sagging occurs due to long-term use and the merchantability is inferior. In addition, since the flat net material is stretched around the seat frame, the basic seat cushion shape is flat, and the three-dimensional shape necessary to support the occupant's body in an optimal position is obtained. As a result, there is a problem that the passengers feel uncomfortable. This is because an unstable hammock-like net material cannot stably support the occupant's body when a lateral G is applied to the occupant by the movement of the automobile.

Next, as for the technique of Patent Document 2, the spring plate is a plate-like foam having a substantially rectangular outer shape, and a plurality of grooves are formed in the lateral direction on the side of the spring plate on which an occupant sits. However, if the groove is shallow, flexibility cannot be given, and if the groove is deep, when the cushion material bends, excessive tensile force concentrates on the connecting part of the remaining groove bottom, causing large elongation deformation. There was a high risk of permanent deformation that could not be restored or fracture. If even a part of the connecting portion at the groove bottom is broken, the support is lost at once, the apparent hardness of the entire cushioning material is drastically lowered, and the function as the cushioning material is greatly impaired. Therefore, it is practically difficult to design the deflection of the cushion material to a certain level or more in order to avoid breakage, and it is difficult to provide a sufficient fit and comfort when seated.

Moreover, although the technique of patent document 2 has described that it can obtain a favorable seating feeling personally by selecting suitably the block from which height differs according to a passenger | crew's physique, There was a problem that in reality it had to be difficult to implement, because it had to be changed to a block of height suitable for me before sitting down by light weight.

Accordingly, an object of the present invention is to provide a seat cushion that is rich in fit and cushioning when a passenger is seated, can be reduced in weight, and is highly recyclable.

In the present invention, the synthetic resin foam is flexible and capable of bending deformation and is excellent in resilience. The method described in JIS K7221-2: 2006 (23 ° C. ± 2 ° C., relative humidity 50 ± 350mm long with skin removed in 5% atmosphere
A load is applied to a test piece having a width of 100 mm and a thickness of 25 mm at a fulcrum distance of 300 mm and a test speed of 20 ± 1 mm / min until the maximum deflection is 90 mm, and a load deflection curve is recorded. ) Refers to a synthetic resin foam molded article having a bending deflection of 20 mm or more and a load of 2 to 100 N when bent by 20 mm. Specifically, it refers to foamed polypropylene, foamed polyethylene, other polyolefin resin foams, modified polystyrene resin foams, and the like. The synthetic resin foam includes a bead foam molded body, and examples of the bead foam molded body include a polypropylene-based bead foam molded body and a polyethylene-based bead foam.

In the specific selection of materials, both ends of a bar-like or plate-like test piece having a length of about 400 mm are supported, the center is pushed back and forth about 25 mm and held for 30 minutes, and then the sample is recovered from deformation immediately after releasing the load. Is desirably 90% or more. Alternatively, in accordance with a test performed on a conventional urethane foam seat cushion, the center portion of the sample supporting both ends is repeatedly pressed down and deformed a predetermined number of times, and the residual strain (also referred to as residual displacement) measured thereafter is measured. It is desirable that the amount is not more than a predetermined amount.

Such materials satisfying, for example, the density of the foamed polypropylene ^{0.06g / cm 3 ~0.015g / cm 3} , more preferably a density 0.035g ^/ cm ³ ~0.015g ^/ cm 3 or polyethylene foam, such as density 0.08g ^/ cm ³ ~0.03g ^/ cm 3 are preferred. On the other hand, rigid foamed urethane, polystyrene foam and the like which are poor in flexibility and can be easily broken by bending deformation are not preferable.

The inventors have studied materials in order to reduce the weight. As an example of a material that can be changed to urethane foam with an open-cell structure, synthetic resin foam that has a closed-cell structure is generally lighter and more rigid than urethane foam that has been generally used as a cushioning material for seat cushions. It has the advantage that it is rich and easy to recycle, but when using a cushion in the direction of compression and restoring force, the reaction force tends to increase rapidly with the deformation of the foam due to the repulsive force of the encapsulated air Therefore, it was felt that the cushioning property was lacking and the comfort was inferior.

In general, when a synthetic resin foam having a closed cell structure is used as a cushioning material by being bent in the compression direction like a urethane foam, it gradually loses its recovery force and generates creep as it is used for a long period of time. This is largely due to fatigue due to repeated deformation of the resin film constituting the bubbles and a drop in the pressure of the air contained therein. Therefore, it is not preferable as a material for automobile seat cushions used for a long time.

Therefore, the inventors analyzed the physical properties of the synthetic resin foam from various angles, so that it is not a structure that has been bent in the compression direction that has been used as a conventional general cushioning material, but can be bent and deformed. The present inventors have found that a method of utilizing the bending deformation and recoverability of a support made of a synthetic resin foam excellent in the above as a cushioning material is optimal.

In order to solve the problem described in “Problems to be Solved by the Invention”, the invention of the seat cushion 1 according to claim 1 is a seat cushion 1 including a seat cushion pad 2, the seat cushion pad 2. However, the amount of bending deflection measured according to the method described in JIS K7221-2: 2006, and the edge-shaped member 10 disposed around the upper edge of the seat cushion pad 2 with a predetermined distance therebetween. And a plurality of independent rod-like or plate-like supports 3 made of a synthetic resin foam having a load of 2 to 100 N when bent by 20 mm, and the shape of the seat cushion pad 2 is changed to the edge member. 10 in the form of one-point support or multiple-point support in the direction of bridging between 10, mounted or fixed on the edge member 10, or integrally formed with the edge member 10, A plurality of support 3 and column set at predetermined intervals form, characterized by having a space portion 5 of the bending deformation is possible the support 3 downwardly of the support 3.

The invention of the seat cushion 1 according to claim 2 is the invention according to claim 1, wherein the elastic body 8 is provided in contact with the bottom surface of the support 3, and the support 3 and the seat frame 7 are separated from each other when no load is applied. When the load due to the seating of the occupant is received, the support body 3 also starts to descend due to the deflection of the elastic body 8.

The invention of the seat cushion 1 according to claim 3 is the invention according to claim 1, wherein the elastic body 8 is provided below the support body 3, and the end portion of the support body 3 and the seat frame 7 are in a connected state from the no-load state. The support 3 starts to bend and deform with the seat frame 7 as a fulcrum immediately after loading.

The invention of the seat cushion 1 according to claim 4 is the invention according to any one of claims 1 to 3, wherein the shape of the support 3 is a straight shape, a curved shape, or a straight line bent at an arbitrary angle in plan view. It is characterized by having a bent shape composed of a combination of the straight portions.

The invention of the seat cushion 1 according to any one of claims 1 to 4 can replace the urethane foam generally used in the past with a synthetic resin foam. Recyclability can be improved. Despite the use of synthetic resin foam, which is relatively hard and inferior to cushioning, fit, and creep resistance, it is possible to give high cushioning and fit, and freedom of design High degree of comfort and high comfort can be obtained, and even when used for a long time, it exhibits excellent creep resistance equivalent to that of conventional urethane foam. Play.

Furthermore, by integrally molding the support 3 and other parts constituting the seat cushion pad 2 with a synthetic resin foam, the processing cost can be reduced and the weight can be reduced.

Next, in the invention of the seat cushion 1 according to the second aspect, when the occupant is seated, the entire support 3 is lowered by elastic expansion or contraction of the elastic body 8 without contacting the seat frame 7. The first form in which the upward reaction force of the elastic body 8 and the weight of the occupant are balanced, and when the occupant is seated, the entire support body 3 is lowered by elastic expansion or contraction of the elastic body 8, and the support After the end of the body 3 comes into contact with the upper portion of the seat frame 7, an upward reaction force generated by bending and deforming the support body 3 downward in a state where both ends are supported, and an upward reaction force of the elastic body 8, There is a second form in which the weight of the passenger is balanced.

In the case of the first embodiment, at the same time that the occupant is seated, the elastic body by the elastic body 8 that supports the support body 3 without making the entire support body 3 made of a synthetic resin foam as a seating surface abut on the seat frame 7. Since the lowering of the entire support 3 with a certain reaction force of the elastic body 8 starts by the elastic expansion or contraction of the elastic body 8, a good seating feeling can be obtained from the time of sitting. And since the support body 3 carries out the bending deformation | transformation by using the elastic body 8 which contacts as it descends, the passenger | crew has a flexible impression and can feel a comfortable seating feeling.

Next, in the case of the second form, the occupant is seated, and at the same time, the support body 3 made of a synthetic resin foam and serving as a seating surface is not brought into contact with the seat frame 7 in the first stage. Since the lowering of the entire support body 3 with a constant reaction force of the elastic body 8 is started by bending deformation with the elastic body 8 supporting the fulcrum and the elastic extension or contraction of the elastic body 8, the seating can be satisfactorily performed. A feeling can be obtained. Then, in the second stage in which the end portion of the support 3 is in contact with the seat frame 7, an upward reaction force of the support 3 is generated by causing bending deformation of the both ends support with the seat frame 7 as a fulcrum. And the upward reaction force of the elastic body 8 can exert cushioning properties according to the weight of the occupant, and the occupant feels that the seating surface is sufficiently flexible and feels comfortable cushioning it can.

  In either the first or second embodiment, the weight of the occupant is applied to the elastic body 8 supporting the support body 3 and the load is distributed to the elastic body 8 and the support body 3, so that the support body is a synthetic resin foam. 3 can reduce the load applied to the occupant 3 when the occupant is subjected to a load, the support body 3 is bent and deformed to exhibit cushioning properties, but its deformation range can be kept within the elastic region, and the elastic body. Since the lowering of 8 is applied, the occupant can obtain a favorable seating feeling upon receiving the impression that the seating surface is sufficiently flexible.

Next, the invention of the seat cushion 1 according to claim 3 is provided with an elastic body 8 below the support 3, that is, in contact with the bottom surface of the support 3 or separated from the bottom of the support 3. The end of the support 3 and the seat frame 7 are in a connected state. In the case of this form, the support 3 starts to bend and deform with the seat frame 7 as a fulcrum immediately after loading. A form in which the elastic body 8 is separated from the support 3 at no load is referred to as a third form, and a form in which the elastic body 8 is in contact with the support 3 is referred to as a fourth form.

In the case of the third form, after the support 3 that has been pressed by the seated person is bent downward and deformed to a certain size or more, the lower part of the support 3 is the elastic body 8. Since the contact force can be increased by the upward reaction force due to the bending deformation of the support body 3 and the upward reaction force due to the tension of the elastic body 8 after the contact, the body sinks more than necessary. Can be suppressed, and the body of the seated person can be supported at an appropriate position.

In the case of the fourth embodiment, the support body 3 and the elastic body 8 that have been pressed by the seated person simultaneously bend and deform downward, and due to the reaction force caused by the bending deformation of the support body 3 and the tension of the elastic body 8. Since the support force can be increased, the body can be prevented from sinking when the weight of the occupant is large, and the body of the heavy occupant can be supported at an appropriate position.

Further, the invention of the seat cushion 1 according to claim 4 is a case where the distance between both ends of the support body 3 cannot be sufficiently secured with a small seat cushion, and sufficient deflection cannot be obtained by the load of the occupant's body. , Between the both ends of the substantial support 3 when subjected to bending deformation by forming the support 3 in an arc shape instead of a linear shape, or a bent shape composed of a combination of straight portions bent at an arbitrary angle Can be increased, and sufficient deflection can be obtained, so that the degree of freedom in design can be increased.

It is a schematic diagram of the seat cushion of the present invention. It is a BB cross-section outline explanatory drawing in Drawing 1, and (a) is an outline explanatory view of a form separated from an edge member which forms the circumference of an upper edge part in a seat cushion pad which has a bottom part, (b) ) Is a schematic explanatory view of a form separated from an edge member that forms a periphery of an upper edge portion in a seat cushion pad that does not have a bottom surface portion. FIG. 2 is a schematic cross-sectional explanatory view taken along the line B-B in FIG. 1. b) is a schematic explanatory diagram of a form in which a support is integrated with an edge member forming the periphery of an upper edge portion in a seat cushion pad having no bottom surface portion. It is an AA cross-sectional outline explanatory drawing in FIG. 1, (a) is an outline explanatory drawing of the support body in the seat cushion pad which has a bottom face part, (b) is an outline of the support body in the seat cushion pad which does not have a bottom face part. It is explanatory drawing. It is explanatory drawing which shows the shape of a support body, (a) is a schematic diagram of a circular-arc-shaped support body, (b) is an outline | summary of the bending-shaped support body which consists of the combination of the linear part which bent the straight line by arbitrary angles. FIG. It is an AA cross-sectional outline explanatory drawing in FIG. 1, and is a cross-sectional outline explanatory drawing of the support body in the seat cushion pad which has a bottom face part. It is an AA cross-sectional outline explanatory drawing in FIG. 1, and is a cross-sectional outline explanatory drawing which shows 1 form which protruded from the bottom face of the support body in the seat cushion pad which has a bottom face part. It is an AA cross-sectional outline explanatory drawing in FIG. 1, and is a cross-sectional outline explanatory drawing which shows 1 form which protruded from the opposing surface of the bottom face of the support body in the seat cushion pad which has a bottom face part. It is a figure which shows the bending test method standardized to JISK7171 or ISO178, (a) is a figure at the time of no load, (b) is a figure at the time of 55kg load. It is explanatory drawing of the form at the time of no load of Claim 2, (a) is a form with which the elastic body was stretched, (b) is explanatory drawing of the form with which the elastic body was provided in the seat frame etc. is there. It is explanatory drawing of the form at the time of no load of Claim 3, (a) is a form which the elastic body is stretched and is contacting the support body, (b) is an elastic body is stretched and the support body is (C) is a form in which the elastic body is provided on the seat frame or the like and is in contact with the support, and (d) is a form in which the elastic body is provided on the seat frame or the like and is not in contact with the support. It is explanatory drawing of a form. It is AA sectional drawing of the vehicle seat cushion of the 2nd form of this invention, and is sectional explanatory drawing at the time of no load. It is AA sectional drawing of the vehicle seat cushion of the 2nd form of this invention, and is a cross-sectional schematic diagram when a load is applied and the seat cushion pad contact | abuts to the seat frame. It is AA sectional drawing of the vehicle seat cushion of the 2nd form of this invention, and it is a cross-sectional schematic diagram during load bending and the seat cushion pad being bent. It is AA sectional drawing of the vehicle seat cushion which provided the insert on the seat frame 7 with the 2nd form of this invention, and is sectional explanatory drawing at the time of no load. It is AA sectional drawing of the vehicle seat cushion which provided the elastic contact body on the seat frame 7 with the 2nd form of this invention, and is sectional explanatory drawing at the time of no load. It is AA sectional drawing of the vehicle seat cushion which provided the elastic contact body on the seat frame 7 with the 2nd form of this invention, and a cross-sectional outline | summary when a load is applied and the seat cushion pad contact | abuts to the seat frame 7 FIG. It is AA sectional drawing of the vehicle seat cushion which provided the elastic contact body on the seat frame 7 with the 2nd form of this invention, and it is a cross-sectional schematic diagram during load bending and the seat cushion pad being bent. It is AA sectional drawing of the vehicle seat cushion of the 1st form of this invention, and is sectional explanatory drawing at the time of no load. It is AA sectional drawing of the vehicle seat cushion of the 1st form of this invention, and is a cross-sectional schematic diagram in which a load is applied and the seat cushion pad is descending. It is explanatory drawing of a deformation | transformation of the seat cushion pad in the AA cross section in the case of the form which does not use an elastic body, Comprising: (a) showed the state at the time of no load, (b) showed the state at the time of load loading. FIG. It is a figure explaining the relationship between the load and displacement of a seat cushion pad when a load is applied by an occupant, where (a) is the second configuration, (b) is the second configuration and the seat frame 7 is a diagram showing a case where an elastic contact body is provided on 7, (c) is a first embodiment, and (d) is a case where a seat cushion pad is not supported by an elastic body but supported by a seat frame 7. It is the figure which showed the example of the installation type of the elastic body of the vehicle seat cushion of this invention, (a) is a 2nd form, and the form by which the elastic body was provided in the back surface of the seat surface, (b) 2nd form, the elastic body is provided on the lateral side of the seat cushion pad, (c) is the second form, and the elastic body is provided on the seat surface side, which is the surface side of the seat cushion pad. It is explanatory drawing which shows the form with which the elastic body was provided in the lower surface of the leg part of a seat cushion pad. It is an outline perspective view of a seat frame which stretched an elastic body. It is an AA cross-sectional outline explanatory drawing in FIG. 1, and is a cross-sectional outline explanatory drawing of the form which stretched the elastic body with the seat cushion pad which does not have a bottom face part. It is explanatory drawing of the kind of elastic body, (a) is a wire-formed screen, (b) is S spring, (c) is a coil spring, (d) is a metal leaf spring, (e) is a torsion coil spring, (f ) Is a view showing a resin body. It is a schematic diagram of a load durability test. It is a schematic diagram of a back pressure jig, (a) is a top view, (b) is a front view, and (c) is a side view. It is a residual displacement amount diagram by repeated load. It is a load-displacement amount diagram in a seat cushion shape. It is a comparison figure of the bending test by JISK7221-2 with a foam and a non-foam. It is a compression-displacement amount diagram in the structure according to claim 3.

Hereinafter, embodiments of the seat cushion 1 according to the present invention will be described.

A seat cushion 1 according to the present invention is a seat cushion 1 including a seat cushion pad 2, wherein the seat cushion pad 2 is disposed so as to face each other with a predetermined interval, and around the upper edge portion of the seat cushion pad 2. And a plurality of synthetic resin foams having a bending deflection amount measured in accordance with the method described in JIS K7221-2: 2006 of 20 mm or more and a load at the time of 20 mm deflection of 2 to 100 N. An independent rod-like or plate-like support 3, and the seat cushion pad 2 is formed on the edge member 10 in the form of one-point support or multiple-point support in the direction of bridging between the edge members 10. Mounted, fitted or fixed, or integrally formed with the edge member 10, and the plurality of supports 3 are arranged at predetermined intervals, To have the space portion 5 is capable of bending deformation of the support 3. Further, when an occupant having a weight of 55 kg is seated, the bending strain generated in the support 3 due to the load of the body weight can be within 5%.

As shown in FIGS. 1 to 3, a support 3 is fixed or integrally formed on an edge-shaped member 10 that forms the periphery of the upper edge of the seat cushion pad 2, and the support 3 is a configuration of the seat cushion pad 2. It is included in the element and forms the seating surface of the seat cushion pad 2. Here, the edge-shaped member 10 may be formed on the entire peripheral edge portion of the upper edge portion of the seat cushion pad 2 or may be formed on the opposite edge portions.

Further, the seat cushion pad 2 is composed of a part including a support 3 serving as a seating surface, a side part 17 and a bottom part 16 constituting a lower part, and a part including the support 3 serving as a seating surface and the side part 17. Or only the support 3 serving as a seating surface. As shown in FIG. 4, a gap 4 is formed between the supports 3. A space 5 is formed below the support 3. In the case where the seat cushion pad 2 is composed only of the support 3 serving as a seating surface, the support 3 is mounted on the seat frame 7.

As shown in FIG. 1, at least the outer peripheral surface of the seat cushion pad 2 is covered with a skin 21 in the seat cushion 1.

Next, the attachment form of the support body 3 is demonstrated. As shown in the partial skin removal range 30 in FIG. As shown in FIG. 2, when the seat cushion pad 2 is separated into the support body 3 and other parts, the support body 3 is formed of the edge member 10 that forms the periphery of the upper edge portion of the seat cushion pad 2. It is fixed on one side facing with one point support, or fixed on both sides of the edge member 10 forming the periphery of the upper edge with multiple point support. Also, as shown in FIG. 3, when the seat cushion pad 2 is integrally formed without being separated into the support 3 and other parts, the support 3 is supported in a single-point support or multiple-point support form. 2 and the edge member 10 forming the periphery of the upper edge portion. A seat frame 7 or a wire 9 is arranged below the peripheral portion on the side where the support 3 is fixed, and rigidity is given to the peripheral portion on the fixed side so that it becomes a fulcrum when the support 3 is bent. preferable.

In addition, each support 3 is provided with a predetermined distance from each other so that each support 3 is not affected by the contact between the adjacent supports 3 and each support 3 can be independently bent differently. Are arranged in an independent state.

Since the individual supports 3 are independent so as not to be affected by the other supports 3 by the gaps 4, it is easy to give completely different bending characteristics to the individual supports 3, and the degree of freedom in design is increased. Since it increases, the seat cushion can be given high cushioning properties and fit, and more comfortable. From this, when a load is applied to the seat cushion by the occupant, each of the portions of the support body 3 that comes into contact with the body is preferable in order to obtain a degree of load due to body pressure distribution or a desirable body holding position. A deflection amount can be given.

In the seat cushion structure described in the cited document 2, a certain amount of deflection is obtained, a desirable cushioning property and a deflection amount that are different for each part are obtained, and even when acceleration is applied to the occupant's body due to vehicle movement, However, it is difficult to provide follow-up for maintaining the desired position. However, in the seat cushion structure of the present invention, each flexible support 3 can operate independently, so that these problems can be easily solved. .

Next, the space | gap 4 provided between each support body 3 is demonstrated. The gap 4 is preferably 2 mm or more and 15 mm or less in width, and the width of one gap 4 may be uniform or may be partially varied depending on the part. If the width of the gap 4 is within the above range, when each support 3 undergoes bending deformation due to the load of the occupant's body, the support 3 arranged adjacent to each other generates low-frequency sounds caused by friction with each other. Inhibition of bending deformation can be suppressed, and the unevenness between the support 3 and the gap 4 at the time of sitting can be further suppressed.

Also, as shown in FIGS. 6 to 8, it is preferable that the width of the gap 4 (interval between the supports 3) is narrow on the seat cushion surface side and designed to be wide below. This is because it is possible to prevent the vehicle 3 from coming into contact with each other when acceleration is applied to the occupant by the movement of the vehicle in the front / rear and left / right directions, and the support body 3 follows this and deforms in a three-dimensionally complicated manner.

Next, the support 3 will be described. The shape of the support 3 is a straight line shape, a curved line shape, or a straight line portion obtained by bending a straight line at an arbitrary angle in any direction within 360 ° including horizontal, vertical, or diagonal in a plan view. Any bent shape may be used. When the width (front-rear direction) of the seat cushion 1 is sufficiently wide, even if the shape of the support 3 is linear, the bending of the support 3 (the limit of bending bending corresponding to the size of the occupant's press) is limited. Can be increased, but if the width of the seat cushion 1 is narrow, it is difficult to increase the bending deflection of the support 3. Therefore, the width (front-rear direction) of the seat cushion 1 is limited in terms of the design of the seat cushion 1, so that it is difficult to secure a satisfactory span for the support body 3. When it is necessary to increase the size, as shown in FIG. 5 (a) or (b), the shape of the support 3 is an arc shape in plan view, or a combination of straight portions obtained by bending a straight line at an arbitrary angle. By deforming into a bent shape, the length of the support body 3 that undergoes substantial bending can be increased and the necessary deflection can be obtained effectively.

Next, the cross-sectional shape of the support 3 can be an arbitrary shape such as a rectangle, a round bar, or an ellipse. In addition, in order to avoid stress concentration at the time of bending deformation, it is preferable that the corner portion has no acute angle portion.

  The size, i.e. width, thickness, length and shape of each support 3 is the optimal cushioning which is determined by the rigidity of the synthetic resin foam used, the expected shape of each part of the occupant's body, the seat position, etc. Designed by the amount of deflection. Specifically, the width of the support 3 in the vertical direction is preferably 12 mm or more and 200 mm or less. The thickness in the front-rear direction is preferably 10 mm or more and 60 mm or less. The smaller the width of the support 3 is, the higher the followability to the body shape is. However, it is preferable that the width is within the above range from the viewpoint of the balance between the durability of the support 3 and the cushioning property and fit. The length of the support 3 is arbitrarily determined depending on the assumed size of the occupant's body, the size of the seat, the support form of the support 3, and the like.

And the support body 3 can also set the form of the support body 3 so that the bending distortion which arises in the said support body 3 by the said load will be less than 5% when the passenger | crew of 55 kg of weight sits down. The reason why the weight of the occupant is set to 55 kg is that the weight per occupant used for calculating the total vehicle weight specified in JIS D0001-2001 is 55 kg.

The seat cushion 1 is required to have sufficient durability and resilience against a repeated load over a long period of time. In general, a solid material including not only a resin material but also a metal material or the like returns to its original form without any deformation after unloading if the deformation caused by the load is within the elastic range. The elastic region has a clear yield point in the stress-strain diagram for materials such as mild steel, and the portion where the stress rises linearly according to the strain before the yield point can be clearly defined as the elastic region. However, the resin does not have a clear yield point, and the material gradually shifts to plastic deformation due to the applied load. In particular, since the synthetic resin foam is soft, accurate measurement is not easy and it is difficult to accurately define the elastic region.

Therefore, the inventors determined that the average body weight of Japanese women aged 20 to 24 years old, as determined by the Ministry of Education, Culture, Sports, Science and Technology, is 50.76 kg as the weight of general adults, and that the total vehicle weight specified in JIS D0001-2001. Based on the fact that the weight per passenger used for calculation is 55 kg, when the weight of the passenger at the time of designing the seat cushion is 55 kg, the residual distortion after repeated use required for the seat cushion 1 can be maintained. In order to keep it within the possible range, trial production was repeated and conditions were searched. As a result, it is concluded that the bending strain generated when a load is applied to the support 3 must be kept within 5% of the bending strain value measured by the method defined in JIS K7171 or ISO178. Reached. Therefore, when the bending strain generated in the support 3 is within 5%, the seat cushion 1 according to the present invention has an effect of further satisfying the durability restoring property against a repeated load over a long period of time.

Explaining that the bending strain is within 5%. The bending strain can be determined according to JIS K7171 or ISO178, which is a standard for bending test methods for hard or semi-rigid plastics. First, a dummy with a load of 55 kg is seated at a normal position of a seat cushion as a test body, and a load applied to each part of the seat cushion is measured. Based on this result, the load applied to the support in each corresponding part is obtained. After that, the amount of deflection generated by applying the obtained load to an experimental sample having the same shape and support form as the corresponding part is measured, and the fulcrum distance of the support and the thickness of the support are specified in JIS K7171. Substituting into the calculated equation (Equation 1), the bending strain is obtained. A schematic bending test method is shown in FIG. FIG. 9 (a) shows that smm deflection occurred when no load was applied and FIG. 9 (b) showed a load of 55kg. The bending strain is calculated from the following relational expression (Formula 1).

Bending strain ε (%) = 600 sh / L ² (Formula 1)
In addition, s: Deflection (mm), h: Thickness (mm) of test piece (support 3), L: Distance between fulcrums (distance between fulcrums supporting the support) (mm). A contact portion between the support 3 and the leg 6 or the seat frame 7 that supports the support 3 at both ends corresponds to the fulcrum.

Therefore, if the deflection (s) of the support 3 when an occupant with a weight of 55 kg is seated is measured, the distance (L) between the left and right ends supporting the support 3 and the thickness (h) of the support 3 are measured. When an occupant having a weight of 55 kg is seated, the bending strain generated in the support 3 due to the load can be obtained.

Therefore, a requirement for satisfying the durability restoration property for a repeated load over a long period was obtained from the residual strain after repeated use. As a result, in order to keep the residual distortion required for the seat cushion 1 after repeated use within a range in which the commercial property can be maintained, trial manufacture was repeated and conditions were searched. As a result, it is concluded that the bending strain generated when a load is applied to the support 3 must be kept within 5% of the bending strain value measured by the method defined in JIS K7171 or ISO178. Reached. In order to make the bending strain within 5%, a combination of the material, form, cross-sectional shape and size of the support 3 is examined and set. If the structure of the support 3 is set so that the bending strain exceeds 5%, it can withstand a small number of loads, but the form of the support cannot be restored to a repeated load over a long period of time. Satisfactory cushioning can be obtained.

By keeping the deflection of the support body 3 within 5% when an occupant with a weight of 55 kg is seated, there is an effect that it is possible to satisfy endurance restoration with respect to repeated loads over a long period of time.

  Next, the elastic body 8 will be described. The elastic body 8 is provided so as to move up and down the support 3 constituting the seat surface of the seat cushion pad 2 made of synthetic resin foam. For example, as shown in FIG. It is provided in contact with the back side of the pad 2), and is provided laterally at the left and right ends of the support 3 (seat cushion pad 2) as shown in FIG. 23 (b), as shown in FIG. 23 (c). As shown in FIG. 23D, the lower surface of the leg of the support 3 (seat cushion pad 2) and the upper surface of the seat frame 75 are provided. There are forms such as being provided between. In any form, when the occupant is seated, the seat cushion pad 2 (support 3) is caused to descend with a certain reaction force necessary to have an impression that the seat surface is flexible, and The seat cushion pad 2 may be in any form that does not cause bending deformation beyond its elastic range.

As shown in FIG. 24 or FIG. 26, the elastic body 8 only needs to have a sufficient restoring force, such as a belt-shaped one in which synthetic fibers such as polyester are spun at a high density (FIG. 24), wire formed Screen (FIG. 26 (a)), S spring (FIG. 26 (b)), coil spring (FIG. 26 (c)), metal leaf spring (FIG. 26 (d)), torsion coil spring (FIG. 26 (e)) In addition, there is a resin body (FIG. 26 (f)) having elasticity such as rubber and urethane, which may be any. The elastic body 8 in a stretched form in FIG. 10 corresponds to, for example, a belt-like one, a wire-formed screen, an S spring, and the like, and the formed elastic body 8 installed on the opposite surface of the support 3 is, for example, a coil Examples include springs and torsion coil springs.

  In the positional relationship among the support 3, the elastic body 8 and the seat frame 7, first, as shown in FIG. 10, the configuration in which the support 3 and the seat frame 7 are separated by the elastic body 8 when no load is applied, Second, as shown in FIG. 11, there is a form in which the support 3 and the seat frame 7 are connected regardless of the position of the elastic body 8 when no load is applied.

  As shown in FIG. 10, when the support 3 and the seat frame 7 are separated from each other by the elastic body 8 at the time of loading, the entire support 3 starts to descend immediately after loading. The form of the elastic body 3 in this case includes a form stretched as shown in FIG. 10A or a form installed on the opposing surface of the support 3 as shown in FIG.

The structure described in claim 2 corresponds to the structure shown in FIG. 10, and the support 3 is generated by lowering the elastic body 8 by elastic expansion or contraction without contacting the seat frame 7. The first configuration in which the reaction force in the direction is balanced, and the support 3 is lowered by the elastic expansion or contraction of the elastic body 8, and after contacting the upper portion of the seat frame 7, the support is supported at both ends. There is a second form in which the upward reaction force generated by bending deformation of 3 downward and the upward reaction force of the elastic body 8 are balanced.

Here, as a comparative example, the elastic body 8 is not provided below the support 3 (seat cushion pad 2), and the support 3 (seat pad 2) is supported in the form of a double-end support beam supported by the seat frame 7. A form having a cushioning property by bending downward will be described.

As shown in FIG. 21 (a), when the support 3 is bent and deformed as shown in FIG. 21 (b) in the form of both-end support beams supported by the seat frame 7, as shown in FIG. 22 (d). In addition, the amount of displacement that bends downward due to the bending deformation of the support 3 changes as shown by the line s in proportion to the weight of the load, and the occupant can feel the cushioning property even though the support 3 has rigidity. it can.

However, the occupant has a tendency to feel higher cushioning when he / she feels the sinking of the seating surface at the moment of sitting, whereas it is difficult to cause the seating surface to sink. In addition, since the synthetic resin foam tends to have a narrow elastic region, there is a concern that when a heavy occupant sits many times, the elastic resin deforms out of the elastic region and cannot be recovered, and the deformation accumulates.

Therefore, in order to allow the passenger to feel the sinking at the moment when the occupant is seated, the support body 3 (seat cushion pad 2) is in the upward biased state when no load is applied, and the seat frame 7 is supported by the elastic body 8 to be supported. The elastic body is maintained without being in contact with the seat frame 7 against the downward force caused by the load when the occupant initially applies the load. The elastic body 8 is caused to generate an upward reaction force while being lowered by elastic expansion or contraction.

With this configuration, the occupant can feel a comfortable cushion that sinks at the moment of sitting.

Therefore, the form of change of the support 3 (seat cushion pad 2) when the occupant is seated is, as a first form, the downward force due to the load of the occupant and the seat cushion pad 2 abuts on the seat frame 7. There is a form in which the upward reaction force of the elastic body 8 generated by the elastic body 8 descending due to elastic expansion or contraction of the elastic body 8 is balanced.

In the case of the first embodiment, as shown in FIG. 19, when there is no load, the support body 3 (seat cushion pad 2) is not in contact with the seat frame 7 by the elastic body 8 supported in the upward biased state. When the occupant's weight is applied while being maintained in a state, the support 3 (seat cushion pad 2) starts to sink and bends and deforms with the elastic body 8 as a fulcrum, as shown in FIG. It sinks until it reaches a reaction force that balances the downward force caused by the passenger's load. FIG. 20 shows that the position h of the surface of the seat cushion pad 2 (support 3) at the time of no load has become a sinking amount j due to the sinking.

Further, as shown in FIG. 22 (c), the amount of displacement that the seat cushion pad 2 (support 3) sinks downward due to elastic expansion or contraction of the elastic body 8 is proportional to the load r. Change as shown. By this change, the occupant can feel a high cushioning property by feeling the sinking of the seating surface from the moment of sitting until the sinking stops.

Next, as a second form of the change of the seat cushion pad 2 (support 3) when the occupant is seated, the downward force due to the load of the occupant and the seat cushion pad 2 are the elastic body 8's. After being lowered by elastic expansion or contraction and coming into contact with the upper part of the seat frame 7, an upward reaction force and elastic body generated by bending deformation of the seat cushion pad 2 (support 3) downward in a state where both ends are supported. There is a form in which the upward reaction force of 8 is balanced.

In the case of the second embodiment, as shown in FIG. 12, when there is no load, the seat cushion pad 2 (support 3) is not in contact with the seat frame 7 by the elastic body 8 supported in the upward biased state. When the occupant's weight is applied while being maintained in the state, the seat cushion pad 2 (support 3) starts to sink as shown in FIG. 13, and sinks while bending with the elastic body 8 as a fulcrum. 14 and then comes into contact with the seat frame 7, and then, as shown in FIG. 14, the seat cushion pad 2 (support 3) has a both-ends support structure with the left and right seat frames 7 as fulcrums, and the seat cushion pad 2 (support The body 3) bends and deforms with both ends as fulcrums.

In addition, the second form includes a form in which an insert 11 such as a non-woven fabric is sandwiched between the seat frame 7 and the seat cushion pad 2 in contact with the seat cushion pad 2 as shown in FIG. It is. The seat frame 7 and the seat cushion pad 2 are not in direct contact with each other. However, since the insert 11 is not an elastic body, the seat cushion pad 2 contacts the left and right inserts 11 at the same time. The cushion pad 2 has a both-end holding structure with the left and right seat frames 7 as fulcrums, and the seat cushion pad 2 bends and deforms with both ends as fulcrums.

Then, as shown in FIG. 22 (a), the amount of displacement of the seat cushion pad 2 that sinks downward due to the elastic expansion or contraction of the elastic body 8 changes as the transition of the line m in proportion to the weight of the load. After that, from the time point k when the seat cushion pad 2 comes into contact with the seat frame 7, the change as shown by the line n is caused by bending deformation of the both ends supporting beam of the seat cushion pad 2. By this change, the occupant can feel a comfortable cushioning property that sinks mainly at the beginning of the seating, and thereafter can feel a comfortable cushioning property that feels like landing with a soft touch.

Further, in the case of the second mode, there is also a mode in which the elastic contact body 12 is provided on the seat frame 7 as shown in FIGS. In this case, when no load is applied, the seat cushion pad 2 is maintained in a state in which the seat frame 7 and the elastic contact body 12 are not in contact with each other by the elastic body 8 supported in the upward biased state as shown in FIG. When the weight of the occupant is loaded, the seat cushion pad 2 starts to sink as shown in FIG. 17 and sinks while bending deformation with the elastic body 8 as a fulcrum. 18, after that, the elastic contact body 12 is compressed and deformed as shown in FIG. 18, and then the seat cushion pad 2 has a double-end holding structure with the left and right seat frames 7 as fulcrums, The seat cushion pad 2 is bent and deformed with both ends as fulcrums. In the present invention, the phrase “abuts on the upper part of the seat frame 7” refers to the case where the seat cushion pad 2 abuts on the seat frame 7 or the elastic contact body 12 on the upper part of the seat frame 7. It also includes the case where it contacts the

The material of the elastic contact body 12 is sufficient when the seat cushion pad 2 descends and comes into contact and is subjected to a load and compresses and deforms within the elastic limit, and when the seat cushion pad 2 rises and separates and becomes unloaded. There are metal plate springs, metal linear springs, S springs, coil springs, rubbers, elastic resin bodies, etc. that have a good restoring force.

Then, as shown in FIG. 22B, the amount of displacement that the seat cushion pad 2 sinks downward due to the elastic expansion or contraction of the elastic body 8 changes in proportion to the weight of the load as the transition of the line m. After that, from the time point k when the seat cushion pad 2 comes into contact with the elastic contact body 12 on the upper part of the seat frame 7, the elastic contact body 12 changes as indicated by a line q due to the compression deformation of the elastic contact body 12. After compression, the change as shown by the line n is caused by the bending deformation of the both ends supporting beam of the seat cushion pad 2. Since the connection point between the line m and the line n is smoothly bent by the line q, the seat cushion 2 for the vehicle is sufficiently flexible when the seat first descends with a certain reaction force when seated. After that, since the body is supported by smooth displacement due to bending deformation of the seat cushion pad 2, a very comfortable seating feeling can be obtained.

Further, in either the first or second form, the weight of the occupant is applied not only to the rigid seat cushion pad 2 but also to the elastic body 8, so that the load applied to the seat cushion pad 2 can be reduced. The seat cushion pad 2 having a narrow elastic range due to rigidity can be used in the elastic range regardless of the weight of the occupant.

Next, an elastic body 8 is provided below the support 3 so that the end of the support 3 and the seat frame 7 are in a connected state from when no load is applied, and the support 3 supports the seat frame 7 immediately after the load. A form (the invention according to claim 3) which starts bending deformation will be described.

In the case of this form, in the no-load state, as shown in FIG. 11A, the support 3 and the seat frame 7 are in contact with each other, and the stretched elastic body 8 is in contact with the bottom surface of the support 3. As shown in FIG. 11B, the support 3 and the seat frame 7 are in contact with each other, and the stretched elastic body 8 is separated from the support 3, as shown in FIG. The support body 3 and the seat frame 7 are in contact with each other, and the elastic body 8 installed on the opposite surface of the support body 3 is in contact with the bottom surface of the support body 3, as shown in FIG. There is a form in which the elastic body 8 that is in contact with the seat frame 7 and is installed on the opposite surface of the support 3 is separated from the support 3. As shown in FIGS. 11 (b) and 11 (d), the configuration in which the elastic body 8 is separated from the support 3 at the time of no load is the third configuration, and as shown in FIGS. A form in which the elastic body 8 is brought into contact with the support 3 at the time of loading is referred to as a fourth form.

In the case of the third form, after the support 3 that has been pressed by the seated person is bent downward and deformed to a certain size or more, the lower part of the support 3 is the elastic body 8. Since the contact force can be increased by the upward reaction force due to the bending deformation of the support body 3 and the upward reaction force due to the tension of the elastic body 8 after the contact, the body sinks more than necessary. Can be suppressed, and the body of the seated person can be supported at an appropriate position.

In the case of the fourth embodiment, the support body 3 and the elastic body 8 that have been pressed by the seated person simultaneously bend and deform downward, and due to the reaction force caused by the bending deformation of the support body 3 and the tension of the elastic body 8. Since the support force can be increased, the body can be prevented from sinking when the weight of the occupant is large, and the body of the heavy occupant can be supported at an appropriate position.

FIG. 25 shows an example of a configuration in which the belt-like elastic body 8 stretched around the seat frame 7 is separated from the support 3 when no load is applied. The support body 3 that has been pressed by the occupant's seat causes a downward bending deformation. After the bending deformation exceeds a certain level, the lower side of the support body 3 contacts the elastic body 8 stretched around the seat frame 7. In addition to suppressing the sinking of the body more than necessary, the body of the seated person is supported by the reaction force due to the bending deformation of the support 3 and the tension of the elastic body 8 after the contact.

  Thereby, even when a passenger | crew's body size differs greatly, it can have cushioning properties suitable for each.

  Next, as shown in FIG. 7, in the seat cushion 1, a protrusion projecting from the bottom surface of a rod-like or plate-like support 3 interposed between the left and right side surface portions 17 of the seat cushion pad 2 in a substantially horizontal direction. As shown in the portion 18 or FIG. 8, the protruding portion 18 projecting toward the space portion 5 on the opposite surface of the bottom surface of the support 3 of the seat cushion pad 2 will be described.

The shape of the protruding portion 18 includes a sharp shape with a sharp tip, a round shape with a rounded tip, or a blunt tip with a flat tip and a flat portion.

After the support body 3 is bent and deformed by the load of the occupant and comes into contact with the support body 3 on the side where the protruding portion 18 faces, the protruding portion 18 and the support body 3 both support the weight of the occupant. The body can be prevented from sinking more than necessary. Since the projecting portion 18 undergoes compressive deformation and the hardness of the seat cushion can be increased stepwise, the body of the seated person can be more reliably supported.

More preferably, the projecting portion 18 has a sharp tip shape, thereby relieving a rapid increase in reaction force that occurs after the projecting portion 18 and the bottom surface portion 16 contact each other, so that the occupant feels a bottom sensation. Can be reduced.

  In FIG. 32, a belt-like elastic body 8 is provided at a position separated below the support 3, and the end of the support 3 and the seat frame 7 are in a connected state from when no load is applied. The example which pressed the test body which has the structure of the invention described in Claim 3 which the body 3 begins to bend and deform | transform using the seat frame 7 as a fulcrum by a testing machine is shown. The reaction force generated when the surface of the seat cushion is pressed to 30 mm at a speed of 100 mm / min with a hemispherical jig having a diameter of 100 mm is shown. The lowest line V is the reaction force when pressing only the belt which is the elastic body 8, the middle line E is the reaction force when pressing only the support 3 made of synthetic resin foam, and the uppermost line G is the structure according to the present invention. It shows the reaction force when pressing the test body with the.

Since the test body having the structure according to the third aspect of the present invention is provided with the belt which is the elastic body 8 at a position 15 mm below the support body 3 made of the synthetic resin foam, the support made of the synthetic resin foam is supported. The body 3 alone and the test body having the structure of the present invention generate exactly the same reaction force until the test body is pressed by 15 mm with a test jig. Thereafter, the support 3 made of a synthetic resin foam is a belt-like elastic body 8. Thereafter, the reaction forces generated by the support 3 made of the synthetic resin foam and the belt-like elastic body 8 are combined to indicate that the rigidity increases step by step.

Next, the synthetic resin foam will be described. The synthetic resin foam in the present invention is flexible, can be bent and deformed, and has excellent restorability. The method described in JIS K7221-2: 2006 (23 ° C. ± 2 ° C., relative humidity 50 ± 5% A test piece having a length of 350 mm, a width of 100 mm, and a thickness of 25 mm, with the skin removed, is applied with a load of up to 90 mm at a fulcrum distance of 300 mm and a test speed of 20 ± 1 mm / min, and a load deflection curve is recorded. It refers to a synthetic resin foamed molded article having a bending deflection of 20 mm or more measured according to the above and a load of 2 to 100 N at the time of 20 mm deflection. A synthetic resin foam molded article that causes fracture when the bending deflection is less than 20 mm is not suitable from the viewpoint of durability. When the cross section of the support body 3 required for supporting the pressing by the body becomes very large and the load at the time of 20 mm bending is more than 100 N, it becomes difficult to generate a preferable bending amount, and a preferable design is difficult. Specifically, it refers to foamed polypropylene, foamed polyethylene, other polyolefin resin foams, modified polystyrene resin foams, and the like. Among the foams, an in-mold molded body of resin foam particles is preferable from the viewpoint of shape flexibility (designability) considering a fit.

The polyolefin resin constituting the expanded particles used in the present invention is a polyolefin resin having an olefin component unit as a main component, specifically, a polypropylene resin, a polyethylene resin, and a mixture of two or more thereof. Is mentioned. The above-mentioned “main component” means that the olefin component unit is contained in the polyolefin resin in an amount of 50% by weight or more, and the content thereof is preferably 75% by weight or more, more preferably 85% by weight. % Or more, more preferably 90% by weight or more.

Examples of the polypropylene-based resin include resins having a propylene component unit of 50% by weight or more, and examples thereof include a propylene homopolymer or a copolymer with another olefin copolymerizable with propylene. Examples of other olefins copolymerizable with propylene include ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1 Examples thereof include α-olefins having 4 to 10 carbon atoms such as heptene and 3-methyl-1-hexene. The copolymer may be a random copolymer or a block copolymer, and may be not only a binary copolymer but also a ternary copolymer. The other olefin copolymerizable with propylene in the copolymer is preferably contained in a proportion of 25% by weight or less, particularly 15% by weight or less, and the lower limit is 0.3% by weight. Preferably there is. These polypropylene resins can be used alone or in combination of two or more. Polypropylene resin has a tensile elastic modulus (E) specified in JIS K7161: 1994 (test piece: JIS K 7162 (1994), test piece 1A type (direct molding by injection molding), test speed: 1 mm / min)). A resin foam obtained by foaming a base resin having a value of 600 MPa or more is preferable.

Examples of the polyethylene resin include resins having an ethylene component unit of 50% by weight or more, such as high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer. A copolymer, an ethylene-propylene-butene 1 copolymer, an ethylene-butene 1 copolymer, an ethylene-hexene 1 copolymer, an ethylene-4 methylpentene 1 copolymer, an ethylene-octene 1 copolymer, and the like. The mixture of 2 or more types is mentioned.

Then, in the specific selection of the synthetic resin foam, both ends of a rod-shaped test piece having a length of about 400 mm are supported, the center is pushed back and forth by 25 mm and held for 30 minutes, and then the load is released, and then the deformation from the sample is changed. Residual strain measured after the center portion of the sample that supported both ends was repeatedly pressed down and deformed in accordance with tests performed on materials with 90% or more recovery or conventional urethane foam seat cushions. A material in which is less than a predetermined amount is desirable. The predetermined number of times or the predetermined amount conforms to a specification arbitrarily determined when each vehicle manufacturer selects a conventional material.

Such materials satisfying, for example, the density of the foamed polypropylene ^{0.06g / cm 3 ~0.015g / cm 3} , more preferably a density ^{0.035g / cm 3 ~0.015g / cm 3} , or of foamed polyethylene such as density 0.08g ^/ cm ³ ~0.03g ^/ cm 3 are preferred. Such a material is obtained by the method described in JIS K7221-2: 2006 (a test piece having a length of 350 mm, a width of 100 mm, and a thickness of 25 mm with the skin removed in an atmosphere of 23 ° C. ± 2 ° C. and a relative humidity of 50 ± 5%. In a test conducted in accordance with a distance between fulcrums of 300 mm, a test speed of 20 ± 1 mm / min up to a maximum of 90 mm, and a load deflection curve is recorded) However, the flexible urethane foam that has been conventionally used is not suitable as a material constituting the seat cushion of the present invention because the flexural rigidity is generally inferior to 0.46 N.

  Below, the creep property and bending rigidity at the time of using a synthetic resin foam are demonstrated. First, in order to evaluate the creep property, compression set according to JIS K 6767: 1999 was measured. A test piece having a length of 50 mm, a width of 50 mm, and a thickness of 25 mm is compressed into a 25% distorted state and left at a temperature of 23 ° C. ± 2 ° C. for 22 hours. The thickness is measured 24 hours after the end of compression. The compression set was determined by compression set (%) = (test piece original thickness (mm) −thickness 24 mm after completion of compression (mm)) ÷ test piece original thickness (mm) × 100.

As a result of the test, the compression set of the 45-fold polypropylene foam particle molded body was 11%. On the other hand, the compression set of the polyurethane foam by the same measuring method is 2% or less. This is because conventional urethane foam, which is generally used as a cushioning material for seat cushions, exhibits cushioning properties by compression deformation. If it is simply replaced with a synthetic resin foam, compression set is generated, and the original cushion It is shown that it is difficult to maintain the product and the commercial value is lowered.

Next, the sample plate 41 is placed at room temperature using a back-shaped pressurizing jig 40 as shown in FIG. 28 (elliptical left and right length 440 mm in plan view, depth (width) 290 mm, height 60 mm in front view). The load displacement test was conducted by measuring the residual displacement after pressing and applying a load of 490 N 5,000 times, 10,000 times, and 15,000 times. In order to investigate the residual displacement when the synthetic resin foam is bent and deformed, as shown in FIG. 27, a flat-plate-shaped product having a thickness of 20 mm and a width (depth) of 600 mm, which is a 45-fold expanded product of expanded polypropylene. The sample plate 41 was used as both-end support at an interval of 340 mm. The results of the load durability test are shown in FIG.

From FIG. 29, the specification required for the conventional urethane foam is a residual displacement of 5 mm or less (line C in FIG. 29), whereas in the case of the synthetic resin foam of the present invention (line D in FIG. 29). ) Indicates that the residual displacement amount is 2.5 mm, which is within the range of the specification.

Therefore, from FIG. 29, when the bending and deformation of a synthetic resin foam that can be bent and is excellent in resilience are used as a cushioning material, it is comparable to a conventionally used urethane foam, or It has been shown to have greater creep resistance.

When the synthetic resin foam is used as the support 3, the creep resistance exceeds that of the urethane foam. When the center part is pushed down and bending deformation occurs, each part of the member is pulled, compressed, sheared, etc. The member deforms, but the degree of each deformation is less than the amount of direct deformation in the case of using a cushion material by simply compressing the member as in the past, and the recovery range is not impaired. Because it stops at.

  Next, FIG. 30 shows a seat cushion type test body using a support 3 made of a synthetic resin foam supported at both ends and a seat cushion type test body using a urethane foam having a conventional structure as shown in FIG. This is an example in which the reaction force generated when pressing at a compression speed of 100 mm / min with a back-shaped processing jig 40 is compared. The size of the test body using urethane foam is 650 mm wide, 350 mm long and 100 mm thick, and the test body using synthetic resin foam is a foamed polypropylene 45 foam product with a length of 350 mm, a width of 50 mm and a thickness of 30 mm. Are arranged in a plurality of rows at intervals of 2 mm. A thin line U shown in FIG. 30 is a load-displacement diagram of urethane foam prepared for comparison and generally used for a seat cushion, and a thick line P is a center of the support 3 made of the synthetic resin foam according to the present invention. It is a load-displacement amount diagram at the time of pushing and bending. Moreover, the load-displacement amount line when pressed down is indicated by u1 and p1, and the load-displacement amount line when released after being pressed is indicated by u2 and p2.

FIG. 30 shows that the support 3 made of a relatively hard synthetic resin foam can obtain almost the same flexibility as a conventional urethane foam when it is structured to obtain cushioning properties by bending deformation. Yes.

Next, FIG. 31 shows a case where foamed polypropylene is selected as an example of a synthetic resin foam, a sample made of a non-foamed resin plate (thickness 1 mm) made of an equivalent resin, and a sample made of a foamed polypropylene 45 times foamed product (thickness 45 mm). ) JIS K7221-2: 2006 (length of 350 mm, width 25 mm, sample weight equivalent, thickness with the skin removed under an atmosphere of 23 ° C. ± 2 ° C. and relative humidity 50 ± 5%. It is a load-displacement diagram in the case where both ends are supported according to 300 mm and a load is applied up to 90 mm at a test speed of 20 ± 1 mm / min, and a load deflection curve is recorded, and this central part is pushed down. The width was kept constant at 25 mm, and the thickness was adjusted so that the sample weight was equal. The case of a non-foamed resin plate is represented by a load-displacement amount diagram M, and the case of a sample made of a foamed polypropylene 45-fold product is represented by a load-displacement diagram H.

FIG. 31 shows that although the weight of the samples is the same, bending rigidity is greatly increased by using a foam. Conventionally, it has not been common to bend a foam and use it as a cushioning material. However, by using a foam, the weight of components required to obtain equivalent bending rigidity can be reduced, that is, the seat cushion 1. It is shown that the weight can be reduced.

DESCRIPTION OF SYMBOLS 1 Seat cushion 2 Seat cushion pad 3 Support body 4 Space | gap 5 Space part 6 Leg 7 Seat frame 8 Elastic body 9 Wire 10 Edge member 11 Insert 12 Elastic contact object 16 Bottom face part 17 Side face part 18 Protrusion part 21 Skin 30 Partial skin removal range 40 Pressure jig 41 Sample plate

Claims (4)

A seat cushion including a seat cushion pad,
The seat cushion pad is
An edge-shaped member formed around the upper edge portion of the seat cushion pad, which is disposed to face each other with a predetermined interval;
A plurality of independent rod-like or plate-like supports made of a synthetic resin foam having a bending deflection amount of 20 mm or more measured in accordance with the method described in JIS K7221-2: 2006 and a load at the time of 20 mm deflection of 2 to 100 N; With
The form of the seat cushion pad,
The plurality of supports are mounted, fitted or fixed on the edge member, or integrally formed with the edge member, in a form of one-point support or multiple-point support in a bridging direction between the edge members. Are arranged in rows with a predetermined interval,
A seat cushion characterized by having a space part under which the support body can be bent and deformed. An elastic body is provided in contact with the bottom surface of the support body, the support body and the seat frame are separated from each other when no load is applied, and the support body also begins to descend due to the deflection of the elastic body when subjected to a load due to the seating of an occupant The seat cushion according to claim 1.   An elastic body is provided below the support, and the end of the support and the seat frame are in a connected state from when no load is applied, and the support starts to bend and deform from the seat frame as a fulcrum immediately after the load. The seat cushion according to claim 1. The form of the said support body is a bending shape which consists of the combination of the linear part which bent the straight line shape, the curve shape, or the straight line at arbitrary angles by planar view, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. Crab seat cushion.

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