JP2009142341A - Seat structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat structure having improved vibration absorption characteristics. <P>SOLUTION: A seat cushion section 10 has a synthetic resin base frame 12 supported by a side frame 11 via a first elastic support mechanism 17, a synthetic resin upper-layer frame 13 supported by the base frame 12 via a second elastic support mechanism 18, an intermediate cushion material 14 placed between the base frame 12 and the upper-layer frame 13 with a part of the intermediate cushion material engaged with the base frame 12, and an upper-layer cushion material 15 for covering the upper-layer frame 13. In the structure above, the two elastic support mechanisms are arranged in series, and this produces a phase difference between motion of the base frame 12 induced by vibration inputted via a vehicle body floor and transmitted to the base frame 12 and motion of the upper-layer frame 13 induced by the vibration further transmitted to the upper-layer frame 13. As a result, in particular, low frequency vibration is effectively absorbed and damped. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a seat structure, and more particularly, to a seat structure suitable as a seat for a transportation device such as an automobile, an aircraft, and a train.

Patent Documents 1 to 5 disclose a seat structure formed by suspending a cushion material such as a three-dimensional knitted fabric (three-dimensional net material) around a seat frame. As described above, when the cushion material is formed over the seat frame, a base net such as a three-dimensional knitted fabric or a two-dimensional fabric is attached to the cushion material in order to prevent bottoming and improve vibration absorption characteristics and shock absorption characteristics. It is provided below via an elastic member. Each of Patent Documents 1 to 5 includes a torsion bar, an arm that is connected to the torsion bar and is rotatably supported with the torsion bar as a fulcrum, and a support frame that is supported by the arm. The torsion bar unit is disposed at the rear portion of the seat portion, and the base net is elastically supported by connecting the rear end of the base net to the support frame.
Japanese Patent Laid-Open No. 2004-347577 JP 2003-182427 A JP 2004-188164 A JP 2004-141545 A WO2004 / 007238A1 publication

  According to the techniques disclosed in Patent Documents 1 to 5, the followability to human body movement is further improved, and vibration absorption characteristics, shock absorption characteristics, etc. are improved, but vibration absorption characteristics and shock absorption characteristics are There is always a need for further improvements.

  On the other hand, the present applicant obtains the change rate of the displacement (amplitude) of the biological signal, for example, in WO 2005/092193, and further calculates the change rate of the amplitude obtained by performing slide calculation with a predetermined slide wrap rate a predetermined number of times. Find time-series data of slope (slope of power value) and time-series data of maximum Lyapunov exponent slope obtained by sliding calculation of the maximum Lyapunov exponent of chaos index in the same way, to detect changes in biological state is suggesting. In addition, as a sensor for detecting a biological signal, a technique of providing an air pack sensor in the vertical direction in the vicinity of a human waist has been proposed. By utilizing the fact that the air pressure of the air pack sensor fluctuates due to breathing, heartbeat, etc., it is detected in time series to capture changes in the biological state.

  In order to detect biological signals such as respiration and heartbeat with high sensitivity using such an air pack sensor, a seat structure that can more effectively absorb vibrations input from the outside as noise is more preferable.

  This invention is made | formed in view of the above, and makes it a subject to provide the seat structure which can improve a vibration absorption characteristic further conventionally.

In order to solve the above-described problem, in the present invention according to claim 1, a synthetic resin having a predetermined width supported by a pair of side frames disposed at a predetermined interval via a first elastic support mechanism. A base frame,
A synthetic resin upper layer frame supported by the base frame via a second elastic support mechanism;
An intermediate cushion material, a part of which is disposed between the base frame and the upper frame and engaged with the base frame;
A seat structure having a seat cushion portion including an upper cushion material covering the upper frame is provided.
In the present invention according to claim 2, the first elastic support mechanism includes a parallel link mechanism having a front link portion and a rear link portion respectively disposed near the front portion and the rear portion of the side frame,
The seat structure according to claim 1, further comprising a torsion bar connected to at least one of the rotation center of the front link portion and the rotation center of the rear link portion.
According to a third aspect of the present invention, the second elastic support mechanism includes a parallel link mechanism having a front link portion and a rear link portion provided to be supported by the base frame in the vicinity of each side portion of the base frame. ,
3. The seat structure according to claim 1, further comprising a torsion bar connected to at least one of the rotation center of the front link portion and the rotation center of the rear link portion.
The invention according to claim 4 is characterized in that the torsion bar of the first elastic support mechanism and the torsion bar of the second elastic support mechanism have different spring constants. A seat structure according to 2 or 3 is provided.
In the present invention described in claim 5, the spring constant of the torsion bar of the first elastic support mechanism is higher than the spring constant of the torsion bar of the second elastic support mechanism. Provides a seat structure.
In the present invention according to claim 6, the front link portion and the rear link portion constituting the parallel link mechanism of the first elastic support mechanism are arranged such that the position of the base frame supported by them is obliquely forward and downward when loaded. 3. The seat structure according to claim 2, wherein the seat structure is mounted so as to be displaced and displaced obliquely rearward and upward at the time of extraction.
In the present invention according to claim 7, in the front link portion and the rear link portion constituting the parallel link mechanism of the second elastic support mechanism, the position of the upper frame supported by the front link portion and the rear link portion is obliquely forward and downward when loaded. 4. The seat structure according to claim 3, wherein the seat structure is mounted so as to be displaced and displaced obliquely upward at the time of extraction.
In the present invention according to claim 8, the upper frame is formed in a plate shape by inserting a two-dimensional net material, and the two-dimensional net material is exposed to the outside at least on the rear surface in the rear portion of the center in the front-rear direction. The seat structure according to claim 1, further comprising an exposed portion.
In this invention of Claim 9, the attachment board which connects both is spanned between the front-link part of the parallel link mechanism in the said 2nd elastic support mechanism, and the front-end | tip of a rear link part,
The upper layer frame has a leaf spring member that sandwiches the attachment plate at a position corresponding to the attachment plate. When the upper layer frame moves relative to the base frame by vibration input, the leaf spring member and the attachment plate The seat structure according to claim 3, 7 or 8, wherein a frictional resistance is generated between the two.
According to a tenth aspect of the present invention, there is provided the seat structure according to the first aspect, wherein the intermediate cushion material is formed of a three-dimensional solid knitted fabric.
The invention according to claim 11 provides the seat structure according to claim 1, wherein the upper cushion material is formed of a three-dimensional solid knitted fabric.

  In the present invention, the seat cushion portion is a synthetic resin base frame supported on the side frame via the first elastic support mechanism, and the composite is supported on the base frame via the second elastic support mechanism. A resin upper layer frame, an intermediate cushion material disposed between the base frame and the upper frame, a part of which is engaged with the base frame, and an upper cushion material covering the upper frame It is characterized by being. The base frame is supported by the first elastic support mechanism, and the upper frame is supported by the base frame by the second elastic support mechanism. In other words, the two elastic support mechanisms support the two mass systems and are arranged in a series relationship, and the motion of the base frame due to the vibration input from the vehicle body floor and the upper frame Since a phase difference is generated with the motion of the upper frame by being transmitted to the low-frequency frame, particularly low-frequency vibrations can be effectively absorbed and attenuated.

  In addition, since an intermediate cushion material is disposed between the base frame and the upper frame, and the upper cushion material is provided on the upper frame, a duffing type non-linear load-displacement characteristic (spring characteristic) is obtained. Since this non-linear spring characteristic occurs, the seat structure of the present invention effectively absorbs low frequency vibrations and also absorbs high frequency vibrations by a synergistic effect with the intermediate cushion material and the upper cushion material. The second elastic support mechanism preferably has a smaller spring constant than the first elastic support mechanism, so that the second elastic support mechanism can absorb high-frequency vibrations together with the intermediate cushion material and the upper cushion material. Play effectively. Moreover, it is preferable to use a three-dimensional solid knitted fabric as the upper cushion material and the intermediate cushion material. The three-dimensional solid knitted fabric has a feature that the dynamic spring constant is small when high-frequency vibration is input, so the vibration transmitted to the human body (upper body) is re-input to the seat cushion through the upper body. Even so, the vibration is absorbed by the upper cushion material and the intermediate cushion material.

  Hereinafter, the present invention will be described in more detail based on the embodiment of the present invention shown in the drawings. As shown in FIGS. 1 to 7, the seat structure 1 according to the present embodiment includes a seat cushion portion 10 and a seat back portion 30 provided so as to be reclining with respect to the seat cushion portion 10.

  The seat cushion portion 10 includes a pair of side frames 11, 11, a base frame 12, an upper layer frame 13, an intermediate cushion material 14, and an upper layer cushion material 15. The side frames 11 and 11 are respectively fixed to slide portions 10b and 10b that are engaged with rails 10a and 10a arranged at a predetermined interval on the vehicle body floor so as to be movable back and forth. (See FIG. 4 and FIG. 8).

  Each side frame 11, 11 is provided with a first elastic support mechanism 17. The first elastic support mechanism 17 is a parallel link including front link portions 171 and 171 that are pivotally supported near the front portions of the side frames 11 and 11 and rear link portions 172 and 172 that are pivotally supported near the rear portions. It has a mechanism.

  The front link portions 171 and 171 are formed in a substantially L shape, and are attached with the bent portions 171c and 171c being pivotally supported on the side frames 11 and 11 with the one having a narrower angle facing the front side. The rear link portions 172 and 172 are also formed in a substantially L shape, similarly to the front link portions 171 and 171, and the bent portions 172 c and 172 c are pivoted to the side frames 11 and 11 with the smaller angle between them facing the front side. It is attached and supported. Between the front link part 171 located on one side frame 11 side and the lower ends 171a and 172a of the rear link part 172, between the front link part 171 located on the other side frame 11 side and the lower ends 171a and 172a of the rear link part 172 Are connected to each end of the connection link plate 173 via a shaft pin.

  Further, a torsion bar 174 is disposed between the bent portions 171c and 171c, which are the rotation centers of the pair of front link portions 171 and 171. When the front link portions 171 and 171 rotate, The torsion bar 174 is twisted and a predetermined elasticity functions. A base frame 12 described later is supported between upper ends 171b and 171b of the pair of front link portions 171 and 171 and between upper ends 172b and 172b of the pair of rear link portions 172 and 172. The torsion bar 174 may be provided not between the front link parts 171 and 171 but between the rear link parts 172 and 172.

  The base frame 12 is formed from a synthetic resin. As shown in FIGS. 9 to 11, a substantially rectangular bottom plate portion 121 in plan view, side plate portions 122 and 122 rising upward from both side edges of the bottom plate portion 121, and upward from a rear edge of the bottom plate portion 121. A predetermined mold is used to form the rear plate portion 123 that rises. As the synthetic resin material, a thermoplastic resin, a thermosetting resin, or the like can be used. In addition, it is possible to use a synthetic resin material in which one or a plurality of four-axis woven fabrics, two-axis woven fabrics, non-woven fabrics, etc. are laminated, thereby increasing the rigidity compared to molding from synthetic resin materials alone. Can do. By using a synthetic resin, a lightweight base frame 12 can be obtained.

  The bottom plate portion 121 is formed in a range in which the width is within the range between the front link portions 171 and 171 and between the rear link portions 172 and 172, and the side plate portions 122 and 122 are respectively formed on the side frames 11 and 11. It is formed in a size and shape that can cover the vicinity of the upper surface from the inner surface (see FIGS. 3 and 6). Connecting portions 121a and 121a project from the front side of the back surface of the bottom plate portion 121 at a predetermined interval in the width direction (see FIG. 11), and the front link portions 171 and 171 are provided on the connecting portions 121a and 121a. The upper ends 171b and 171b are connected. Further, screw connection holes 122b and 122b are formed on the rear sides of the side plate parts 122 and 122 (see FIG. 11), and the rear link part 172 is inserted into the screw connection holes 122b and 122b via screw members. , 172 are connected at the upper ends 172b, 172b. As a result, the base frame 12 is elastically supported by the first elastic support mechanism 17.

  As shown in FIGS. 9 and 10, grooves 124 and 124 that are long in the front-rear direction are provided between the bottom plate portion 121 and the side plate portions 122 and 122, respectively. Front link portions 181 and 181 and rear link portions 182 and 182 constituting a parallel link mechanism of the two elastic support mechanisms 18 are disposed. Specifically, the base end portions of the front link portions 181 and 181 and the rear link portions 182 and 182 are pivotally supported at the front portion and the rear portion of the groove portions 124 and 124, respectively. Mounting plates 183 and 183 are bridged between the front link part 181 and the rear link part 182 and between the front link part 181 and the rear link part 182 located in the other groove part 124, respectively. The upper frame 13 described later is supported by the mounting plates 183 and 183. Further, a torsion bar 184 is provided between the base end portions of the front link portions 181 and 181. As shown in FIG. 11, the portions where the groove portions 124 and 124 are formed protrude to the back surface side of the bottom plate portion 121, so a torsion bar 184 is provided on the back surface side of the bottom plate portion 121, and the groove portions 124 and 124 are formed. The formed groove wall parts 124a and 124a are penetrated and connected to the base end parts of the front link parts 181 and 181. As a result, the upper frame 13 is elastically supported by the second elastic support mechanism 18 including the parallel link mechanism and the torsion bar 184. In the present embodiment, the torsion bar 184 is disposed between the front link portions 181 and 181, but may be disposed between the rear link portions 182 and 182.

Here, the first elastic support mechanism 17 functions to support the weight of the seated person and to absorb and attenuate vibrations of large amplitude mainly at low frequencies. On the other hand, the second elastic support mechanism 18 mainly causes high-frequency and small-amplitude vibrations that have not been isolated by the first elastic support mechanism 17 to have a phase with respect to the movement of the first elastic support mechanism 17. Absorb by moving out of position. Moreover, the function which supports the intermediate cushion material 14 mentioned later so that it may not be crushed so much in the thickness direction in the state where the person statically seated is fulfilled. Therefore, the torsion bar 174 constituting the first elastic support mechanism 17 and the torsion bar 184 constituting the second elastic support mechanism 18 have a spring constant in the former torsion bar 174 than in the latter torsion bar 184. It is preferable to use one having a high value. A preferable spring constant of the torsion bar 174 constituting the first elastic support mechanism 17 is in a range of 1000 to 3000 N · mm / deg, and a preferable spring constant of the torsion bar 184 constituting the second elastic support mechanism 18. Is in the range of 800-1500 N · mm / deg.
However, this is the most preferable embodiment. The first elastic support mechanism 17 starts to move under the influence of the vertical vibration input mainly input from the floor, and the second elastic support mechanism 18 is mainly seated by the vibration of the seat back portion 30. The phase shift occurs because two mass systems controlled by different input conditions are arranged in series, such as starting to move under the influence of acceleration generated by the movement of the upper body of This is a mechanism for damping vibration. In other words, the present invention has two elastic support mechanisms 17 and 18 for the purpose of absorbing vibrations by moving with the phases of the two deviating from each other. A spring constant of the torsion bar 174 constituting the elastic support mechanism 17 may be smaller than the spring constant of the torsion bar 184 constituting the second elastic support mechanism 18, and two torsion may be adopted. It is also possible to employ the bars 174 and 184 having the same spring constant.

  Similar to the base frame 12, the upper frame 13 is molded into a predetermined shape from a synthetic resin such as a thermoplastic resin or a thermosetting resin. The upper frame 13 is formed to have the same width and length as the base frame 12 and the bottom plate part 121, and has a predetermined flexibility in a thickness of 5 mm or less, preferably in the range of 1 to 2 mm. Of course, like the base frame 12, one or a plurality of two-dimensional net materials made of a 4-axis woven fabric, a 3-axis woven fabric, a 2-axis woven fabric, a non-woven fabric, etc. can be laminated on the synthetic resin material. (Rigidity) can be adjusted. The upper frame 13 can also be reduced in weight by forming it from a synthetic resin.

  In addition, as shown in FIG. 12, the two-dimensional net member 130 is inserted and laminated on the upper layer frame 13 of the present embodiment within the range of the thickness of the upper layer frame 13. And the exposed part 13a which exposes the two-dimensional net | network material 130 outside is formed in the rear part rather than the center in the front-back direction on the back surface side of the upper layer frame 13. The exposed portion 13a is preferably formed in a range located below the sciatic nodule when a person is seated, and is opened forward from the rear end of the upper frame 13 from a range of 50 mm to 100 mm, and further to the front 100 mm to It is preferable that the opening is made up to a range of 200 mm. The width is preferably opened in the range of 50 mm to 100 mm from the center in the width direction to the left and right. As a result, in the range of the exposed portion 13a, it becomes easier to sink than other portions, and at the time of sitting, the boundary between the portion in the range of the exposed portion 13a and the other portion of the upper frame 13 serves as a weir. It is possible to stabilize the position of the sciatic nodule and to suppress the pelvic front-back sliding. Although the two-dimensional net member 130 is exposed only on the back surface side of the upper layer frame 13, it may be exposed also on the front surface side.

  When the impact force is applied by laminating the two-dimensional net material 130, the synthetic resin plate portion of the upper frame 13 that is located across the two-dimensional net material 130 and the two-dimensional net material 130. Delamination occurs between the two. In the delamination, the entire two-dimensional net member 130 is not peeled off from the synthetic resin plate portion at once, but the portion where the exposed portion 13a is formed easily sinks. The delamination with the plate portion occurs, which becomes a trigger and the delamination range expands as the impact load increases. The joining force between the two-dimensional net member 130 and the synthetic resin plate portion that resists delamination at this time acts as a damping force against the impact, and helps absorb the impact energy.

  As shown in FIGS. 9 and 12, on both sides of the back side of the upper layer frame 13, the mounting plates 183 and 183 spanned between the left and right front link portions 181 and 181 and the rear link portions 182 and 182 are connected. Connecting members 135 and 135 are provided. Each of the connecting members 135 and 135 is composed of a pair of leaf spring members 135a and 135a provided at intervals similar to the width of the mounting plates 183 and 183, and a pair of guide pins 135b provided separately in the front-rear direction. , 135b. Guide holes 183b and 183b are formed in the mounting plates 183 and 183 so as to be separated from each other in the front-rear direction. The guide pins 135b and 135b are inserted into the guide holes 183b and 183b, and the mounting plates 183 and 183 are moved to the plate spring members. It arrange | positions so that it may be pinched | interposed by 135a and 135a. As a result, each mounting plate 183 is positioned between the pair of leaf spring members 135a and 135a. When relative displacement occurs between the two at the time of vibration, the vibration is attenuated by friction between the two. Fulfill.

  Further, as shown in FIGS. 5 and 10, a substantially cylindrical rubber member 127 having a part opened is attached near the front edge of the bottom plate portion 121 in the base frame 12. An engagement pin 136 provided on the rear surface side of the front edge of the upper frame 13 is engaged with 127. This is to reduce the feeling of bottoming due to the upper layer frame 13 coming into contact with the base frame 12.

  As shown in FIGS. 7 and 9, an intermediate cushion material 14 is provided between the base frame 12 and the upper frame 13. On the surface side of the bottom plate portion 121 of the base frame 12, as shown in FIGS. 7, 9, and 10, engagement protrusions 125, 125 are provided near the front edge portion and the rear edge portion, The engagement protrusions 125 are engaged with the vicinity of the front edge portion and the vicinity of the rear edge portion of the intermediate cushion material 14, respectively. The intermediate cushion material 14 is preferably formed from a three-dimensional solid knitted fabric. The three-dimensional solid knitted fabric is knitted by reciprocating a connecting yarn between a pair of ground knitted fabrics positioned at a predetermined interval, and is formed into a predetermined shape using a double raschel machine or the like, for example, Asahi Kasei ( Co., Ltd., product number: T24004A, or Sumie Textile Co., Ltd. product numbers: 49076D, 49013D, etc. can be used. As can be seen from the vibration characteristics shown in the Lissajous figure of FIG. 15, the three-dimensional solid knitted fabric has a very small spring constant (dynamic spring constant) under vibration conditions when high frequency vibration of about 7 Hz or more is input. (The dynamic spring constant is zero near 9 Hz and negative at higher frequencies), and the vibration isolating ability of high-frequency vibration is high. On the other hand, if the intermediate cushion material 14 made of a three-dimensional solid knitted material is crushed when a person is seated, the elasticity due to such a low spring constant does not function during vibration input. Therefore, as described above, it is preferable that the second elastic support mechanism 18 is set so that the intermediate cushion material 14 can be supported so as not to be crushed in the thickness direction in a state where a person is seated statically.

  In addition, the above-described three-dimensional solid knitted fabric was placed on a two-dimensional base net stretched between a pair of support frames that are elastically supported by a torsion bar placed before and after the seat cushion portion, and vibration characteristics were examined. However, the results shown in FIG. 16 were obtained. That is, this is a vibration characteristic of a combined structure of a mechanism having a positive spring characteristic and a mechanism having a negative spring characteristic. From this result, such a combined structure has a low spring constant of a three-dimensional solid knitted fabric alone. From around 7 Hz, the spring constant decreases in the same way, and after 9 Hz, where the spring constant of the three-dimensional solid knitted fabric itself is substantially zero or negative, the spring constant of the combined structure also becomes substantially zero, eliminating high frequency vibration. It can be seen that the shaking ability is high.

  The Lissajous figure shown in FIGS. 15 and 16 is a sine wave with a circular weight of 12.7 kg set on a three-dimensional solid knitted fabric and an amplitude on one side of 1 mm (amplitude between upper and lower peaks 2 mm (2 mmpp)). FIG. 4 shows the relationship between the relative displacement amount of the weight and the load acting on the weight by applying vibration in 20 steps from the vibration frequency of 0.5 Hz to 10 Hz.

  The upper layer cushion material 15 is disposed so as to cover the upper layer frame 13. As the upper cushion material 15, urethane, fiber cushion, three-dimensional solid knitted fabric, or the like can be used, but it is preferable to use a three-dimensional solid knitted fabric similarly to the intermediate cushion material 14. The three-dimensional solid knitted fabric is excellent in the absorption characteristics of high-frequency vibration as described above. When vibration that cannot be removed from the time it is input from the vehicle body floor and transmitted to the buttocks is input from the buttocks to the upper body, resonance occurs in the upper body. When shaken by resonance, the upper body becomes a vibration source, and vibration is re-input to the seat cushion portion 10 side. When the force due to the returned vibration is combined with the acceleration when the seat cushion part resonates due to this vibration, the person perceives it as a slight vibration. This combined micro-vibration is superposed with high-frequency so-called dirty vibrations, resulting in subharmonic resonance. Therefore, a layer that absorbs and attenuates high-frequency vibration generated in both directions between the seat cushion portion 10 and the human body is required. However, the upper cushion material 15 and the intermediate cushion material 14 have high high-frequency vibration absorption characteristics. By using a three-dimensional solid knitted fabric, such unpleasant micro vibrations generated in both directions can be reduced. 2 and FIG. 9 is a cover member that covers the side plate portions 122 and 122 and the rear plate portion 123 of the base frame 12. Like the upper cushion material 15, urethane, fiber cushion, tertiary It is formed using an original three-dimensional knitted fabric or the like.

  In addition, the structure of the seat back part 30 of this embodiment is not limited. For example, a three-dimensional solid knitted fabric supported on a metal frame-shaped frame material, a synthetic resin frame covering the metal frame material is attached to a metal frame-shaped frame material, and the The thing etc. which arrange | positioned the three-dimensional solid knitting so that the surface may be covered can be used.

  According to this embodiment, when sitting from the no-load state shown in FIG. 13A, the upper cushion material 15 sinks as shown in FIG. The torsion bar 184 of the elastic support mechanism 18 is first twisted. At this time, since the spring constant is low, a person is seated while feeling a soft spring feeling. As the load is further applied, the torsion bar 174 of the first elastic support mechanism 17 is twisted, and the human body is firmly supported by the high spring constant. Here, FIG. 14 is a diagram showing a load-deflection characteristic when the seat cushion portion 10 is pressurized to 1000 N at 50 mm / min by a pressure plate having a diameter of 200 mm. As shown in this figure, the spring constant k1 in the bound direction obtained from the load-deflection characteristic when the second elastic support mechanism 18 is acting at the beginning of pressurization is 12.7 N / mm. The spring constant k2 in the bound direction obtained from the load-deflection characteristics when the action of the first elastic support mechanism 174 was also added was 23.8 N / mm. The spring constant in the bound direction is preferably set so that k1 is in the range of 5 to 20 N / mm and k2 is in the range of 15 to 50 N / mm. Moreover, since the site | part in the range of the exposed part 13a which has exposed the two-dimensional net | network 130 is easy to sink into the upper frame 13 as mentioned above, the shift | offset | difference of the front and back of a pelvis is suppressed and it stabilized Can take a sitting posture.

  When vibration is input from the vehicle body floor in such a state, each of the spring elements of the first elastic support mechanism 17, the second elastic support mechanism 18, the intermediate cushion material 14, and the upper cushion material 15 receives the input vibration. Acts according to acceleration. In other words, the spring element that acts mainly changes according to the input vibration, so that various input vibrations can be handled. For example, when a large amplitude vibration is input at a low frequency, the torsion bar 174 of the first elastic support mechanism 17 and the torsion bar 184 of the second elastic support mechanism 18 are in a series relationship. By acting both, the spring constant becomes small, and vibration can be absorbed and attenuated. In addition, when high-frequency and small-amplitude vibration is input, the torsion bar 174 of the second elastic support mechanism 17 and the intermediate cushion material 14 act in a parallel relationship to effectively perform vibration isolation and attenuation. be able to. Further, as described above, high-frequency fine vibration that is input to the human body and returns to the seat cushion portion 10 side is vibration-isolated and attenuated by the upper cushion material 15 and the intermediate cushion material 14 and re-input to the human body. The influence of unpleasant vibration can be reduced.

  More specifically, the first elastic support mechanism 17 starts to move under the influence of vertical vibration input mainly input from the floor. On the other hand, the second elastic support mechanism 18 starts to move under the influence of acceleration generated by the movement of the upper body of the seated person mainly due to the vibration of the seat back portion 30. Since the two mass systems governed by these different input conditions are arranged in series, a phase shift occurs and the vibration is attenuated. When the inclination angle of the seat back portion 30 is small, the load shared by the seat cushion portion 10 is large, so that the above-described phase shift causes a nearly complete opposite phase to reduce vibration.

  On the other hand, when the seat back part 30 is inclined and the load sharing ratio of the seat cushion part 10: the seat back part 30 is about 6: 4, the anti-phase is less complete, so that the vibration cannot be completely eliminated by the phase shift Low frequency vibration remains. On the other hand, the posture with such a shared load ratio is a relaxed posture, and the sympathetic and parasympathetic nerves are well balanced and low-frequency respiratory movement is likely to occur, but at this time, low-frequency vibration is also input from the seat As a result, low-frequency breathing exercises can be assisted to promote deeper and natural breathing. This increases the ventilation rate of the lungs and promotes fatigue recovery.

(Test example)
A vehicle body floor obtained by setting the seat according to the above embodiment (Example 1) on a vibration exciter and taking a sine wave or a random wave while the subject is seated (running on a general road in Michigan, USA at around 100 km / h) The vibration transmissibility was measured by conducting a test of exciting the vibration waveform. The spring constant of the torsion bar 174 of the first elastic support mechanism 17 used in this test was 1417 N · mm / deg, and the spring constant of the torsion bar 184 of the second elastic support mechanism 18 was 879 N · mm / deg. It was. In addition, the spring constant of the bound direction of the seat cushion part 10 was as having shown in FIG. As the intermediate cushion material 14, a three-dimensional solid knitted fabric having a duffing-type spring characteristic having a dead zone and made by Sumie Textile Co., Ltd., product number: 49076D and a thickness of 11 to 14 mm was used. As the upper cushion material 15, a three-dimensional solid knitted fabric having a product number of 49013D and a thickness of 11 to 14 mm manufactured by Sumie Textile Co., Ltd. was used. The seat back portion 30 has a structure in which a synthetic resin frame that covers the metal frame material is attached to a metal frame-shaped frame material, and a three-dimensional solid knitted fabric is disposed so as to cover the surface thereof. Met.

  For comparison, the applicant has disclosed a two-dimensional base between a pair of support frames elastically supported by a seat disclosed in JP-A-2006-345952, that is, a torsion bar disposed before and after the seat cushion portion. Place a net and set a sheet (Comparative Example 1) with a three-dimensional solid knitted fabric stretched at a low elongation of 5% or less to cover the frame-like cushion frame on the top of the net. Then, a test similar to the above was performed. In addition, the structure of the seat back part of the comparative example 1 was the same structure as the said Example 1. Furthermore, on the inner surface of the shell-shaped frame made of carbon, Asahi Kasei Co., Ltd., product number: T24004A, made of Sumie Textile Co., Ltd. laminated on the surface side, product number: 49013D, has a two-layer structure, A sports car seat (Comparative Example 2) on which a three-dimensional solid knitted fabric having a thickness of 6 to 14 mm was attached was also set on a shaker and subjected to the same test as described above.

  Subject A (Japanese male: weight 70 kg) was seated on the seat of Example 1 and the seat of Comparative Example 1, and was vibrated with a sine wave (0.5 to 15 Hz) with a one-side amplitude of 1 mm (peak-to-peak amplitude of 2 mm). In this case, the vibration transmissibility was measured for the case of exciting with a random wave. The test results of subject A are shown in FIGS. In addition, the subject B (Japanese male: weight 58 kg) was seated on the seat of Example 1 and the seat of Comparative Example 2, and the vibration transmissibility was measured when the sine wave and the random wave were vibrated. The test results of subject B are shown in FIGS.

  As is clear from FIGS. 17 and 18, the sheet of Example 1 has a reduced vibration transmissibility at the resonance point as compared with the sheet of Comparative Example 1, and the vibration transmissibility in a high frequency region of 7 Hz or higher. It can be seen that is reduced. 19 and 20 also show that the sheet of Example 1 has a lower vibration transmissibility at the resonance point and the high frequency region than the sheet of Comparative Example 2.

  Further, when looking at the vibration transmissibility when vibrating with random waves in FIGS. 18 and 20, the vibration transmissibility around 3 to 5 Hz, which is 10 times the frequency of respiration (0.3 to 0.5 Hz), is averaged. Thus, it can be estimated that the low frequency vibration of 3 to 5 Hz slightly acts on the subject and can assist breathing motion.

FIG. 1 is a perspective view showing a seat structure according to an embodiment of the present invention. FIG. 2 is a front view showing the seat structure according to the embodiment. FIG. 3 is a side view of FIG. FIG. 4 is a bottom view of FIG. 5 is a cross-sectional view taken along line AA in FIG. FIG. 6 is a perspective view of the seat structure shown in FIG. 2 as viewed from the bottom surface direction. FIG. 7 is a cross-sectional view showing the configuration of the seat cushion portion. FIG. 8 is a view showing the frame in a state where the base frame, the upper frame, and various cushion materials are removed from the seat structure of FIG. 9 is an exploded perspective view of the seat cushion portion of the seat structure of FIG. FIG. 10 is a perspective view of the base cushion constituting the seat cushion portion as seen from the top surface direction. FIG. 11 is a perspective view of the base cushion constituting the seat cushion portion as viewed from the bottom. 12A is a perspective view of the upper frame as viewed from the top surface, and FIG. 12B is a perspective view of the upper frame as viewed from the bottom. FIGS. 13A and 13B are views for explaining the operation of the first elastic support mechanism and the second elastic support mechanism at the time of sitting. FIG. 14 is a diagram illustrating the load-deflection characteristics of the seat cushion portion. FIG. 15 is a Lissajous figure showing the vibration characteristics due to displacement excitation of a three-dimensional solid knitted fabric. FIG. 16 is a Lissajous figure showing vibration characteristics due to displacement excitation of a three-dimensional solid knitted fabric supported by a torsion bar having positive spring characteristics. FIG. 17 is a diagram showing the vibration transmissibility when subject A sits on the seats of Example 1 and Comparative Example 1 and vibrates with a sine wave. FIG. 18 is a diagram illustrating the vibration transmissibility when subject A sits on the seats of Example 1 and Comparative Example 1 and vibrates with random waves. FIG. 19 is a diagram showing the vibration transmissibility when subject A sits on the seats of Example 1 and Comparative Example 2 and vibrates with a sine wave. FIG. 20 is a diagram showing the vibration transmissibility when subject A sits on the seats of Example 1 and Comparative Example 2 and vibrates with random waves.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seat structure 10 Seat cushion part 11 Side frame 12 Base frame 13 Upper layer frame 13a Exposed part 130 Two-dimensional net material 135 Connection member 135a Leaf spring member 135b Guide pin 14 Intermediate cushion material 15 Upper layer cushion material 17 1st elastic support mechanism 171 Front link portion 172 Rear link portion 173 Connection link plate 174 Torsion bar 18 Second elastic support mechanism 181 Front link portion 182 Rear link portion 183 Mounting plate 184 Torsion bar

Claims (11)

A base frame made of synthetic resin having a predetermined width supported via a first elastic support mechanism on a pair of side frames arranged at a predetermined interval;
A synthetic resin upper layer frame supported by the base frame via a second elastic support mechanism;
An intermediate cushion material, a part of which is disposed between the base frame and the upper frame and engaged with the base frame;
A seat structure comprising a seat cushion portion including an upper cushion material covering the upper frame. The first elastic support mechanism includes a parallel link mechanism having a front link part and a rear link part respectively disposed near the front part and the rear part of the side frame,
The seat structure according to claim 1, further comprising a torsion bar coupled to at least one of the rotation center of the front link portion and the rotation center of the rear link portion. The second elastic support mechanism includes a parallel link mechanism having a front link part and a rear link part provided to be supported by the base frame in the vicinity of each side part of the base frame,
3. The seat structure according to claim 1, further comprising a torsion bar connected to at least one of the rotation center of the front link portion and the rotation center of the rear link portion.   4. The seat structure according to claim 2, wherein the torsion bar of the first elastic support mechanism and the torsion bar of the second elastic support mechanism have different spring constants.   The seat structure according to claim 4, wherein a spring constant of the torsion bar of the first elastic support mechanism is higher than a spring constant of the torsion bar of the second elastic support mechanism.   The front link portion and the rear link portion constituting the parallel link mechanism of the first elastic support mechanism are such that the position of the base frame supported by them is displaced obliquely forward and downward when loaded, and obliquely rearward and upward when deloaded. 3. The seat structure according to claim 2, wherein the seat structure is attached so as to be displaced.   The front link portion and the rear link portion that constitute the parallel link mechanism of the second elastic support mechanism are such that the position of the upper frame supported by the front link portion and the rear link portion is displaced obliquely forward and downward when loaded, and obliquely rearward and upward when pulled. The seat structure according to claim 3, wherein the seat structure is attached so as to be displaced.   The upper layer frame is formed in a plate shape by inserting a two-dimensional net material, and has an exposed portion that exposes the two-dimensional net material to the outside at least on the rear surface in the rear part of the center in the front-rear direction. The seat structure according to claim 1, wherein: Between the front link part and the rear link part of the parallel link mechanism in the second elastic support mechanism, a mounting plate for connecting both is bridged,
The upper layer frame has a leaf spring member that sandwiches the attachment plate at a position corresponding to the attachment plate. When the upper layer frame moves relative to the base frame by vibration input, the leaf spring member and the attachment plate The seat structure according to claim 3, 7 or 8, wherein a frictional resistance is generated between the two.   The seat structure according to claim 1, wherein the intermediate cushion material is formed of a three-dimensional solid knitted fabric.   The seat structure according to claim 1, wherein the upper layer cushion material is formed of a three-dimensional solid knitted fabric.

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