Patent Publication Number: US-2015083872-A1

Title: Seat mounting structure

Description:
TECHNICAL FIELD 
     The present invention relates to a seat mounting structure. 
     BACKGROUND ART 
     Some conventional vehicles are provided with stowable rear seats so that the rear seat space can be expanded when there is no passenger on the rear seats. The seat frames of such seats are supported by right and left support members that are mounted on the floor (for example, see Patent Document 1). 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: JP 2010-100229A 
       
    
     SUMMARY OF INVENTION 
     Problem to be Solved by the Invention 
     There has been a demand for stably mounting a seat frame on a floor. 
     Accordingly, it is an object of the present invention to provide a seat mounting structure that can stably mount a seat frame. 
     Means for Solving the Problem 
     In order to solve the above problems, the invention described in claim  1  is a seat mounting structure, including: 
     right and left support members which support a seat frame of a seat within a floor of a vehicle; and 
     a coupling member which is hung between the right and left support members to couple the support members with each other, 
     wherein at least one of the right and left support members comprises:
         a base part;   a sidewall part which extends upward from the base part, and to which the seat frame and the coupling member are attached; and   a first mounting part and a second mounting part which fix the base part on the floor, and       

     wherein a coupling section of the sidewall part to which the coupling member is coupled is disposed in a space created by upwardly projecting a region connecting the first mounting part and the second mounting part. 
     The invention described in claim  2  is the seat mounting structure according to claim  1 , 
     wherein the sidewall part comprises a protrusion which protrudes to at least one of right and left, and the coupling section is provided at a tip of the protrusion, so that the coupling section is disposed in the space. 
     The invention described in claim  3  is the seat mounting structure according to claim  1 , 
     wherein the sidewall part protrudes toward the inside of the vehicle so that the coupling section is disposed in the space. 
     The invention described in claim  4  is the seat mounting structure according to any one of claims  1  to  3 , 
     wherein a lower end of the sidewall part protrudes with respect to an upper end of the sidewall part so that the coupling section is disposed in the space. 
     The invention described in claim  5  is the seat mounting structure according to any one of claims  1  to  4 , 
     wherein the sidewall part comprises a rolling shaft attaching part on which a rolling shaft of the seat frame is mounted, and 
     wherein the rolling shaft attaching part as well as the coupling section is disposed in the space. 
     The invention described in claim  6  is the seat mounting structure according to claim  4  or  5 , 
     wherein an engaging member with which a lower end of the seat frame is engaged is disposed at an upper end of the sidewall part, 
     wherein the sidewall part comprises a rolling shaft attaching part on which a rolling shaft of the seat frame is attached, and 
     wherein a part of the sidewall part below the rolling shaft attaching part protrudes with respect to the rolling shaft attaching part so that the coupling section is disposed in the space. 
     The invention described in claim  7  is the seat mounting structure according to any one of claims  1  to  6 , 
     wherein the coupling section is disposed on a virtual plane connecting centers of the first mounting part and the second mounting part. 
     The invention described in claim  8  is the seat mounting structure according to any one of claims  1  to  7 , 
     wherein the first mounting part is disposed at a front side of the coupling section, and the second mounting part is disposed at a rear side of the coupling section, 
     wherein a center of the first mounting part is located at an outer side with respect to the coupling section, and 
     wherein a center of the second mounting part is located at an inner side with respect to the coupling section. 
     The invention described in claim  9  is the seat mounting structure according to claim  8 , 
     wherein a most inwardly protruding part of a wheel house in the vehicle is opposed to the second mounting part at an inner side of the most inwardly protruding part in a right-left direction. 
     The invention described in claim  10  is the seat mounting structure according to claim  8  or  9 , 
     wherein the support member is disposed along a wheel house in the vehicle. 
     The invention described in claim  11  is the seat mounting structure according to any one of claims  8  to  10 , 
     wherein at least a part of a wheel house in the vehicle comprises a suspension house that protrudes inward to house a suspension, and 
     wherein the suspension house is opposed to the second mounting part. 
     The invention described in claim  12  is the seat mounting structure according to claim  11 , 
     wherein the suspension house is a most inwardly protruding part of the wheel house in the vehicle, and 
     wherein the first mounting part is disposed in an area at a front side of a front step of the suspension house. 
     The invention described in claim  13  is the seat mounting structure according to claims  12 , 
     wherein the coupling section is disposed opposite to the front step. 
     Effects of Invention 
     According to the invention described in claim  1 , the coupling member is disposed in a space that is created by upwardly projecting a region formed by connecting the first and the second mounting parts. Accordingly, the weight of the coupling member acts on the support member via the coupling section in an approximately vertical direction. If the coupling section is disposed outside the space, the weight of the coupling member acts on the support member in a diagonal direction, which may make the support members unstable. In contrast, disposing the coupling section in the space can stabilize the mounting strength of the support member. 
     According to claim  2 , the sidewall part protrudes to either the right or the left so that the coupling section is disposed in the space. This protrusion can enhance the rigidity of the support member. 
     According to the invention described in claim  3 , the sidewall part is formed such that the coupling section protrudes toward the inside of the vehicle. This can conserve the space in the width direction of the vehicle. 
     According to the invention described in claim  4 , the lower end of the sidewall part protrudes with respect to the upper end of the sidewall part. This can further enhance the rigidity of the support member. 
     According to the invention described in claim  5 , the rolling shaft attaching part and the coupling section are disposed in the space. This can allow a force acting on the rolling shaft attaching part to act on the support member in an approximately vertical direction. As a result, this can further stabilize the mounting strength of the support member. 
     According to the invention described in claim  6 , the engaging member with which the lower end of the seat frame is engaged is disposed at the upper end of the sidewall part. That is, the engaging member is disposed at the upper end, which forms a step with respect to the lower end of the sidewall part. This can prevent an increase in size. 
     Further, the part of the sidewall part below the rolling shaft attaching part protrudes with respect to the rolling shaft attaching part. This can further enhance the rigidity of the support member even when the rolling shaft attaching part is provided. 
     According to the invention described in claim  7 , the coupling section is disposed on the virtual plane connecting the centers of the first and second mounting parts. This allows the weight of the coupling member to act on the support member in the vertical direction. As a result, this can further stabilize the mounting strength of the support member. 
     According to the invention described in claim  8 , the center of the first mounting part is located at the outer side with respect to the coupling section, and the center of the second mounting part is located at the inner side with respect to the coupling section. Accordingly, the region connecting the first and second mounting parts is diagonal to the extending direction of the coupling member. This inclination of the region with respect to the extending direction of the coupling member makes the structure robust against forces in both the fore-aft direction and the right-left direction. 
     According to the invention described in claim  9 , the most inwardly protruding part of the wheel house is opposed to the second mounting part. That is, the most inwardly protruding part of the wheel house is disposed at the outer side of the second mounting part that is located at the inner side with respect to the first mounting part. This can make efficient use of the installation space. 
     According to the invention described in claim  10 , the support member is disposed along the wheel house in the vehicle. This can make efficient use of the area narrowed inwardly by the wheel house for mounting the support member. Further, in case the support member  4  is about to be deformed outward, the wheel house can support the support member from the outer side, and thus can prevent the support member from falling down. 
     According to the invention described in claim  11 , the suspension house and the second mounting part are opposed to each other. This can make efficient use of the installation space even when the suspension house is provided in the wheel house. 
     According to the invention described in claim  12 , the first mounting part is disposed in the area at the front side of the front step of the suspension house, which is the most inwardly protruding part of the wheel house. This can make efficient use of the installation space. 
     According to the invention described in claim  13 , the coupling section is disposed opposite to the front step. This allows the coupling section to be close to the front step, and can thus make efficient use of the installation space. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  This is a perspective view of a rear seat according to an embodiment of the present invention, illustrating the schematic configuration thereof. 
         FIG. 2  This is a top view of a rear seat mounting structure according an embodiment of the present invention, illustrating the schematic configuration thereof. 
         FIG. 3  This is a perspective view of a support member according to an embodiment of the present invention, illustrating the schematic configuration thereof. 
         FIG. 4  This is a front view of the support member in  FIG. 3 . 
         FIG. 5  This is a top view of a space where a coupling section according to an embodiment of the present invention is disposed. 
         FIG. 6A  This is a top view of support members according to a first variation, illustrating the schematic configuration thereof. 
         FIG. 6B  This is a perspective view of the support members according to the first variation, illustrating the schematic configuration thereof. 
         FIG. 7  This is a top view of a space where a coupling section of the first variation is disposed. 
         FIG. 8A  This is a top view of support members according to a second variation, illustrating the schematic configuration thereof. 
         FIG. 8B  This is a perspective view of the support members according to the second variation, illustrating the schematic configuration thereof. 
         FIG. 9A  This is a top view of support members according to a third variation, illustrating the schematic configuration thereof. 
         FIG. 9B  This is a perspective view of the support members according to the third variation, illustrating the schematic configuration thereof. 
         FIG. 10  This is a top view of support members according to a fourth variation, illustrating the schematic configuration thereof. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of the present invention will be described with the drawings. While the following embodiment includes a variety of limitations that are technically preferable for embodying the present invention, the scope of the present invention is not limited to the following embodiment or the illustrated examples. 
       FIG. 1  is a perspective view of a rear seat according to the embodiment of the present invention, illustrating the schematic configuration thereof. As illustrated in  FIG. 1 , a rear seat  1  is provided with a seat frame  2  that is covered with a seat pad (not shown) and is disposed in a reclinable manner in the fore-aft direction. At the right and left lower ends of the seat frame  2 , a seat mounting structure  3  according to the present invention is applied. With this structure, the seat frame  2  can be reclined/raised in the fore-aft direction. 
     Hereinafter, the seat mounting structure  3  according to the present invention will be described in more detail.  FIG. 2  is a top view of the seat mounting structure  3 , illustrating the schematic configuration thereof. As illustrated in  FIG. 1  and  FIG. 2 , the seat mounting structure  3  includes a pair of right and left support members  4  that support the seat frame  2  in a floor of a vehicle, a coupling member  5  that is hung between the pair of left and right support members  4  to couple the pair of support members  4  with each other, and engaging members  6  to engage the right and left lower ends of the seat frame  2  respectively with the pair of support members  4 . 
       FIG. 3  is a perspective view of the support member  4 , illustrating the schematic configuration thereof, and  FIG. 4  is a front view of the support member  4 . As illustrated in  FIG. 2  through  FIG. 4 , each of the support members  4  includes a base part  41  that is mounted on the floor surface of a floor F, a sidewall part  42  that extends upward from the base part  41 , and a pair of fixing parts  43  that fix the base part  41  on the floor surface of the floor F. 
     The base part  41  extends in the fore-aft direction such that the front end is disposed at an outer side and the rear end is disposed at an inner side. At the front end and the rear end of the base part  41 , a pair of fixing holes  411  is formed, to which the fixing parts  43  are attached. 
     The fixing parts  43  include bolts  431  and washers  432 . By inserting the bolts  431  in the washers  432  and fixing holes  411 , and screwing them into tapped holes (not shown) of the floor F, the base part  41  is affixed to the floor F by the fixing parts  43 . The fixing part  43  attached at the front part of the base part  41  corresponds to a first mounting part of the present invention, and the fixing part  43  attached at the rear part of the base part  41  corresponds to a second mounting part of the present invention. 
     The sidewall part  42  extends upward from the outer part of the edge of the base part  41 , and the lower end thereof protrudes toward the inside of the vehicle with respect to the upper end thereof. This protrusion of the sidewall part  42  serves as a coupling section  421  where the coupling member  5  is attached. Accordingly, the pair of fixing parts  43  is positioned so as to sandwich the coupling section  421  in the fore-aft direction. Further, the center of the front fixing part  43  is located at the outer side with respect to the coupling section  421 , and the center of the rear fixing part  43  is located at the inner side with respect to the coupling section  421 . 
     On the upper end of the sidewall part  42 , a rolling shaft attaching part  422  is provided, where a rolling shaft  21  of the seat frame  2  is attached via an engaging member  6 . 
     The coupling section  421  and the rolling shaft attaching part  422  are disposed in a space S, which is created by upwardly projecting the region connecting the pair of fixing parts  43 . Specifically, as illustrated in  FIG. 5 , the space S is a space that is created by upwardly projecting the region formed by connecting the inner and outer ends of one washer  432  of the pair of fixing parts  43  respectively with the inner and outer ends of the other washer  432  (see the hatched area in  FIG. 5 ). It is required that at least a part of the coupling section  421  and at least a part of the rolling shaft attaching part  422  are disposed in the space S. However, it is preferred that the whole coupling section  421  and the whole rolling shaft attaching part  422  are disposed in the space S. As illustrated in  FIG. 5 , it is also preferred that the positioning of the rolling shaft attaching part  422  and the coupling section  421  intersects with a virtual plane L5 connecting the centers of the pair of fixing parts  43  in the space S. 
     Further, at the front end and the rear end of the base part  41 , ribs  412  that continue to the sidewall part  42  are formed. These ribs  412  enhance the rigidity of the whole support member  4 . In terms of enhancing the rigidity, it is preferred that the ribs  412  are formed not only at the front end and the rear end of the base part  41  but also extend continuously to the protruded lower end of the sidewall part  42 . 
     As described above, the base part  41  is disposed such that the front end is located at the outer side and the rear end is located at the inner side, and the sidewall part  42  protrudes inward at the center part. Accordingly, each support member  4  can be disposed around a wheel house W of the vehicle along the front end of the wheel house W of the vehicle. To be more specific, as illustrated in  FIG. 2 , at least a part of the wheel house W is a suspension house w 1  that protrudes inward to house a suspension. In addition to the suspension house w 1 , the wheel house W may also include a fuel pipe house that houses a fuel pipe, etc. 
     The suspension house w 1  is the part of the wheel house W that protrudes the most. The suspension house w 1  and the rear fixing part  43  are disposed opposite to each other at the inner side in the right-left direction of this most protruded part. Further, the front fixing part  43  is disposed in an area at the front side of a front step w 2  of the suspension house w 1 . Accordingly, the support member  4  is disposed along the extension line L3 of the wall of the front step w 2 . With this arrangement of the support member  4  along the wheel house W, the area narrowed inward by the wheel house W can be effectively used for mounting the support member  4 . Further, in case the support member  4  is about to be deformed outward, the wheel house W can support the support member  4  from the outer side, and thus can prevent the support member  4  from falling down. 
     Further, since the coupling section  421  is disposed opposite to the front step w 2 , the coupling section  421  can be disposed close to the front step w 2 . This can make efficient use of the installation space. 
     The coupling member  5  is a bar member that extends in the right-left direction as illustrated in  FIG. 1  and  FIG. 2 . At predetermined positions of the coupling member  5 , locking members  51  for mounting a child seat or the like are fixed. Further, at the center part of the coupling member  5 , a fixture  52  that fixes the coupling member  5  on the floor F is attached. 
     As described above, according to the embodiment of the present invention, each coupling section  421  is disposed in the space S, which is created by upwardly projecting the region connecting the pair of fixing parts  43 . Accordingly, the weight of the coupling member  5  acts on the support members  4  in an approximately vertical direction via the coupling sections  421 . If each coupling section  421  is located outside the space S, the weight of the coupling member  5  acts diagonally on the support members  4 , which may make the support members  4  unstable. In contrast, disposing each coupling section  421  in the space S can stabilize the mounting strength of the support members  4 . 
     Further, each sidewall part  42  is configured such that the lower end protrudes with respect to the upper end. This can enhance the rigidity of the support members  4 . 
     Further, each engaging member  6  is disposed at the upper end of the sidewall part  42 . That is, each engaging member  6  is disposed at the upper end of the sidewall part  42  that forms a step with respect to the lower end. This can prevent an increase in size. 
     Further, the part below the rolling shaft attaching part  422  of each sidewall part  42  protrudes with respect to the rolling shaft attaching part  422 . This can enhance the rigidity of the support members  4  even when the rolling shaft attaching parts  422  are provided. 
     Further, in addition to the coupling section  422 , each rolling shaft attaching part  42  is disposed in the space S. This allows a force acting on the rolling shaft attaching part  42  to also act on the support member  4  in an approximately vertical direction. This can further stabilize the mounting strength of the support members  4 . 
     Further, the center of each front fixing part  43  is located at the outer side with respect to the coupling section  422 , and the center of each rear fixing part  43  is located at the inner side with respect to the coupling section  422 . Accordingly, the region connecting the pair of fixing parts  43  is diagonal to the extending direction of the coupling member  5 . If the region connecting the pair of fixing parts is parallel to the extending direction of the coupling member  5 , the structure is vulnerable to a force in the fore-aft direction. If the region is orthogonal to the extending direction of the coupling member  5 , the structure is vulnerable to a force in the right-left direction. In contrast, since the region is diagonal to the extending direction of the coupling member  5 , the structure is robust against forces in both fore-aft direction and right-left direction. 
     Further, each rear fixing part  43  is opposed to the most inwardly protruding part of the wheel house W (e.g. suspension house w 1 ). Accordingly, the most inwardly protruding part is located at the outer side of the rear fixing part  43  that is located at the inner side with respect to the front fixing part  43 . This can make efficient use of the installation space. 
     Further, each front fixing part  43  is disposed in the area at the front side of the front step w 2  of the suspension house w 1 , which is the most inwardly protruding part of the wheel house W. This can make efficient use of the installation space. 
     Further, since each coupling section  422  is disposed opposite to the front step w 2 , the coupling section  422  can be disposed close to the front step w 2 . This can make efficient use of the installation space. 
     The seat mounting structure can be fixed on the floor F after the support members  4 , the coupling member  5 , the engaging members  6  and the rolling shaft  21  are assembled to the seat frame  2 . This eliminates the need for a horizontal tightening operation in the vehicle. As a result, the workability of assembly can be improved in comparison to a procedure whereby only the support members  4  are initially fixed to the floor F, after which other parts are assembled thereto. 
     The embodiments to which the present invention is applicable are not limited to the above-described embodiment, and may be suitably changed without departing from the present invention. In the following description, the portions that are similar to those of the above-described embodiment are referred to by the same reference signs, and the descriptions thereof are omitted. 
       FIG. 6A  is a top view of support members according to a first variation, illustrating the schematic configuration thereof, and  FIG. 6B  is a perspective view of the support members according to the first variation, illustrating the schematic configuration thereof. 
     Each of the support members  4 A illustrated in  FIG. 6A  and  FIG. 6B  includes a base part  41   a  that is disposed on the floor surface of a floor F, a sidewall part  42   a  that extends upward from the base part  41   a , and a pair of fixing parts  43   a  that fix the base part  41   a  on the floor surface of the floor F. 
     The base part  41   a  extends in the fore-aft direction. At the front end and the rear end thereof, a pair of fixing holes  411   a  where the fixing parts  43   a  are attached is formed. The pair of fixing holes  411   a  is disposed on a line L1 that is parallel to the fore-aft direction. 
     The fixing parts  43   a  include bolts  431  and washers  432 . By inserting the bolts  431  in the washers  432  and the fixing holes  411  and screwing them into tapped holes (not shown) of the floor F, the base part  41  is fixed to the floor F by the fixing parts  43   a . Since the fixing parts  43   a  are fixed on the floor F through the pair of fixing holes  411 , the pair of fixing parts  43   a  attached on the base part  41   a  is also disposed on the line L1. 
     The sidewall part  42   a  extends upward from the outer part of the edge of the base part  41   a , and the center part thereof protrudes toward the inside of the vehicle. The tip of the center part (protrusion) of the sidewall part  42   a  is a coupling section  421   a  to which a coupling member  5  is attached. The coupling section  421   a  is disposed in a space S1, which is created by upwardly projecting the region connecting the pair of fixing parts  43 . Specifically, as illustrated in  FIG. 7 , the space S1 is a space that is created by upwardly projecting the region formed by connecting the inner and outer ends of one washer  432  of the pair of fixing parts  43   a  to the inner and outer ends of the other washer  432 , respectively (see the hatched area in  FIG. 7 ). That is, in the space S1, the coupling section  421   a  may not be disposed on a line L1 parallel to the fore-aft direction as illustrated in  FIG. 6A  and  FIG. 6B , but may be disposed diagonal to the line L1. 
     On the upper end of the sidewall part  42   a , a rolling shaft hole  422   a  is formed, to which a rolling shaft  21  of the seat frame  2  is attached via an engaging member  6 . 
     Further, at the front end and the rear end of the base part  41   a , ribs  412   a  that continue to the sidewall part  42   a  are formed. These ribs  412   a  enhance the rigidity of the whole support member  4 A. 
     Also in the first variation, each coupling section  421   a  is disposed in the space S1, which is created by upwardly projecting the region connecting the pair of fixing part  43 . Accordingly, the weight of the coupling member  5  acts on the support members  4 A in an approximately vertical direction via the coupling sections  421   a . If each coupling section  421   a  is located outside the space S1, the weight of the coupling member  5  acts diagonally on the support members  4 A, which may make the support members  4 A unstable. In contrast, disposing each coupling section  421   a  in the space S1 enables stabilization of the mounting strength of the support members  4 A. 
     Further, each sidewall part  42   a  protrudes to either the right or the left so that the coupling section  421   a  is disposed in the space S1. This protruded part of each sidewall part  42   a  can enhance the rigidity of the support members  4 A. 
     Further, each sidewall part  42   a  is formed such that the coupling section  421   a  protrudes toward the inside of the vehicle. This can conserve the space in the direction of the vehicle width. 
     In the first variation, each sidewall part  42   a  is formed such that the coupling section  421   a  protrudes toward the inside of the vehicle. However, each sidewall part may be formed such that the coupling section protrudes toward the outside of the vehicle. 
       FIG. 8A  is a top view of support members  4 B according to a second variation, illustrating the schematic configuration thereof, and  FIG. 8B  is a perspective view of the support members  4 B, illustrating the schematic configuration thereof. 
     Each of the support members  4 B includes a base part  41   a  that is mounted on the floor surface of a floor F, a sidewall part  42   b  that extends upward from the base part  41   a , and a pair of fixing parts  43   a  that fix the base part  41   b  on the floor surface of the floor F. 
     The sidewall part  42   b  extends upward from the inner part of the edge of the base part  41   a , and the center part thereof protrudes toward the outside of the vehicle. The center part of the sidewall part  42   b  is hollow, and a coupling member  5  is attached on the inner side. That is, the center part of the sidewall part  42   b  is a coupling section  421   b  to which the coupling member  5  is attached. The coupling section  421   b  is disposed in a space S1, which is created by upwardly projecting the region connecting the pair of the fixing parts  43   a.    
     Further, at the front end and the rear end of the base part  41   a , ribs  412   b  that continue to the sidewall part  42   b  are formed. The ribs  412   b  enhance the rigidity of the whole support member  4 B. 
     As described above, the sidewall part  42   b  is formed such that the coupling section  421   b  protrudes toward the outside of the vehicle. This can further stabilize the coupling member  5  by supporting the coupling member  5  with a broader area. 
     In the first and second variations, each sidewall part  42   a  or  42   b  is formed such that the coupling section  421   a  or  421   b  protrudes. However, the sidewall part may not include a protrusion. 
       FIG. 9A  is a top view of support members  4 C according to a third variation, illustrating the schematic configuration thereof, and  FIG. 9B  is a perspective view of the support members  4 C, illustrating the schematic configuration thereof. 
     Each of the support members  4 C includes a base part  41   a  that is mounted on the floor surface of the floor F, a sidewall part  42   c  that extends upward from the base part  41   a , and a pair of fixing parts  43   a  that fixes the base part  41   a  on the floor surface of the floor F. 
     The sidewall part  42   c  extends upward from the center of the base part  41   a  along a line L1. At the center part of the sidewall part  42   c , a coupling member  5  is attached. That is, the center part of the sidewall part  42   c  is a coupling section  421   c  to which the coupling member  5  is attached. The coupling section  421   c  is disposed on a virtual plane connecting the centers of the pair of fixing parts  43   a  (illustrated as the line L1 in  FIG. 9A ). 
     As described above, the coupling section  421   c  is disposed on the virtual plane L1 connecting the centers of the pair of fixing parts  43   a . This allows the weight of the coupling member  5  to act on the support members  4 C in the vertical direction. As a result, this can further stabilize the mounting strength of the support members  4 C. 
     In each of the above-described embodiments, the pair of right and left support members  4 ,  4 A,  4 B or  4 C has the same shape. However, the right and left support members may have different shapes from each other in conformity with the shape of the floor F of the vehicle. 
     The above-described embodiments illustrate examples in which each support member  4  is provided with two fixing parts  43 . However, each support member  4  may be provided with three of more fixing parts  43 .  FIG. 10  is a top view illustrating a space where a coupling section is disposed on a support member that includes three fixing parts. As illustrated in  FIG. 10 , a base part  41   d  of a support member  4 D is configured such that the lines connecting fixing parts  43  form an approximately triangular shape in which the fixing parts  43   d  are provided at the respective corners. The coupling section  421   d  is disposed in a region surrounded by the fixing parts  43   d  (hatched area of  FIG. 10 ). Further, it is preferred that the coupling section  421  is disposed at the point where straight lines L7 that pass through the centers of the fixing parts  43   d  intersect. 
     The above-described embodiments illustrate examples in which the rear seat  1  is employed as the seat. However, the seat mounting structure  3  of the present invention is also applicable to mid seats and front seats in addition to the rear seat  1 . 
     The above-described embodiments illustrate examples in which the first mounting part and the second mounting part are fixed on the floor F by bolts. However, at least one of the first mounting part or the second mounting part may be fixed on the floor F by welding. Also in this case, it is preferred that the coupling section is disposed in a space that is created by upwardly projecting a region connecting the welded parts (first and second mounting parts) welded on the floor F. 
     INDUSTRIAL APPLICABILITY 
     The seat mounting structure according to the present invention is applicable to seats installed in a vehicle. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
         
           
               1  rear seat 
               2  seat frame 
               3  mounting structure (seat mounting structure) 
               4  support member 
               5  coupling member 
               6  engaging member 
               21  rolling shaft 
               41  base part 
               42  sidewall part 
               43  fixing part (first and second mounting parts) 
               421  coupling section 
               422  rolling shaft attaching part 
             F floor 
             S space 
             W wheel house 
             w 1  suspension house 
             w 2  front step