Fixing structure of pipe nut

Abstract

To provide a fixing structure of a pipe nut which enables improvement of production efficiency and further enables improvement of attachment rigidity of the pipe nut to a vehicle body frame even if the pipe nut is joined to the vehicle body frame by spot welding.SOLUTION: A fixing structure of a pipe nut includes: a pipe nut main part 14a in which a female screw part 14e is formed and which penetrates through a front side frame 6 having a hollow cross section 15; a joint flange part 14b which is provided at a base end of the pipe nut main part 14a and contacts with an outer surface of the front side frame 6 to restrict movement of the pipe nut main part 14a in a longitudinal direction; and a nut 20 which is provided at the pipe nut main part 14a and contacts with a surface of the front side frame 6 which is different from the outer surface of the front side frame 6 with which the pipe nut main part 14a contacts to restrict movement of the pipe nut main part 14a in the longitudinal direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a fixing structure for pipe nuts provided on a vehicle body frame for bolt fastening a subframe to the vehicle body frame. [Background technology]

[0002] Conventionally, front side frames extending in the longitudinal direction are disposed on both sides of the front of a vehicle body of an automobile, etc. Below the front side frames, subframes such as suspension cross members that support the suspension and the like extend in the vehicle width direction.

[0003] Both ends of such a suspension cross member are generally attached to the front side frames by bolts, and for this reason, the front side frames are provided with pipe nuts with internal threads to fasten both ends of the suspension cross member to the front side frames with bolts.

[0004] The pipe nut is generally joined to the front side frame by welding means such as spot welding or arc welding.

[0005] Various techniques have been proposed as fixing structures for pipe nuts to increase the mounting rigidity.

[0006] For example, Patent Document 1 (Japanese Patent No. 6337342) discloses a pipe nut that is inserted into a body frame from below and protrudes upward. Furthermore, a flange portion at the base end of the pipe nut abuts against the bottom surface of the body frame. The pipe nut fixing structure is then disclosed, in which the outer periphery of the flange abutting against the bottom surface of the body frame is joined by arc welding.

[0007] The flange portion is provided with a seating surface against which the mounting portion of the suspension cross member abuts. Arc welding, which joins the outer periphery of the flange portion provided with such a seating surface, generates spatter during welding. Therefore, during arc welding, it is necessary to protect this seating surface with a masking material to prevent the adhesion of spatter. Protecting the seating surface with a masking material requires a separate process of attaching and detaching the masking material before and after the arc welding process. The technology disclosed in Patent Document 1 requires a separate process of attaching and detaching the masking material, which increases the number of work steps and disadvantageously reduces production efficiency.

[0008] As a welding method for preventing such a decrease in production efficiency and increasing production efficiency, spot welding, which is less likely to generate spatter, may be considered. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 6337342 Summary of the Invention [Problem to be solved by the invention]

[0010] However, spot welding may make it more difficult to ensure the installation rigidity of the pipe nut compared to arc welding, which joins the pipe nut with a line.

[0011] The present invention has been made in consideration of the above circumstances, and has an object to provide a pipe nut fixing structure that improves production efficiency and ensures the attachment rigidity of the pipe nut to the vehicle body frame even when the pipe nut is joined to the vehicle body frame by spot welding. [Means for solving the problem]

[0012] A pipe nut fixing structure according to one aspect of the present invention includes a pipe nut body having an internally formed female thread portion and penetrating a body frame having a hollow cross section; a first stopper provided at the base end of the pipe nut body and abutting against the outer surface of the body frame to restrict longitudinal movement of the pipe nut body; and a second stopper provided on the pipe nut body and abutting against a surface of the body frame different from the outer surface of the body frame on which the first stopper abuts to restrict the longitudinal movement of the pipe nut body. [Effects of the Invention]

[0013] The pipe nut fixing structure of the present invention improves production efficiency and ensures the attachment rigidity of the pipe nut to the vehicle body frame even when the pipe nut is joined to the vehicle body frame by spot welding. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is an exploded perspective view of a body frame and a suspension cross member according to a first embodiment. [Figure 2] FIG. 1 is an enlarged perspective view of a main portion of a body frame according to a first embodiment; [Figure 3] FIG. 1 is an exploded perspective view showing an enlarged view of a main part of a body frame according to a first embodiment; [Figure 4] IV-IV cross-sectional view of FIG. 2 according to the first embodiment. [Figure 5] 1 is a perspective view of a pipe nut according to a first embodiment, viewed obliquely from below; [Figure 6] 6 is a cross-sectional view taken along line VI-VI of FIG. 4 according to the first embodiment; [Figure 7] 6 according to the second embodiment. [Figure 8] 6 according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0016] In the drawings used in the following description, different scales are used for each component so that each component can be recognized on the drawing. Therefore, the present invention is not limited to the number of components, the shapes of components, the size ratios of components, and the relative positional relationships of each component shown in these drawings. Furthermore, in the following description, when the term "joining" is used, it is assumed that the joining method is performed using a joining means such as fusion joining or mechanical joining. In the drawings, only spot welding points that indicate characteristic parts are marked with spot welding symbols, and welding symbols are omitted for other welding points. [First embodiment]

[0017] As shown in FIG. 1, an engine room 2 is provided in the front part of a vehicle body 1.

[0018] The engine room 2 is separated from the rear cabin 3 by a toeboard 4.

[0019] The vehicle body 1 has frames that make up the engine compartment 2, including a pair of left and right front side frames 6, a pair of left and right upper side frames 7, and a suspension cross member 9. These frames are formed, for example, by pressing sheet metal members made of high-strength steel plate or the like.

[0020] The basic structure around the pair of left and right front side frames 6 and the pair of left and right upper side frames 7 is symmetrical. Therefore, the left side of the vehicle body will be described below as an example.

[0021] As shown in FIG. 1, the front side frames 6 extend from the lower part of the toe board 4 toward the front of the vehicle body 1 on the outer sides of the toe board 4 in the vehicle width direction.

[0022] The upper side frames 7 are provided above the front side frames 6 and further outward in the vehicle width direction than the front side frames 6. The upper side frames 7 extend along the engine compartment 2 toward the front of the vehicle body.

[0023] A suspension tower 8 is provided between the front side frame 6 and the upper side frame 7 near the rear of the engine room 2 .

[0024] The suspension tower 8 accommodates a suspension device (not shown) therein and supports the upper part of the suspension device.

[0025] Furthermore, a wheel apron 5 is provided between the front side frame 6 and the upper side frame 7, in front of the suspension tower 8.

[0026] The suspension cross member 9 is disposed as a subframe below the front side frame 6. That is, the suspension cross member 9 extends in the vehicle width direction below the front side frame 6. The suspension cross member 9 has a shape in which the center portion curves downward.

[0027] The ends of such suspension cross members 9 in the vehicle width direction are joined to the bottom surfaces of the front side frames 6 by bolting.

[0028] In order to fasten such a suspension cross member 9 with bolts, a pair of pipe nuts 14 are provided on the front and rear of the front side frame 6, which serves as the body frame.

[0029] The configuration of the front side frame 6 and the suspension cross member 9 will be described in detail below.

[0030] 1 and 2, the front side frame 6 has an inner frame 12 and an outer frame 13. Note that in FIG. 1, a portion of the outer frame 13 of the left front side frame 6 is omitted.

[0031] 2 to 4, the inner frame 12 has a generally hat-shaped cross section that protrudes inward in the vehicle width direction. The inner frame 12 has an inner wall portion 12a, an upper wall portion 12b, a lower wall portion 12c, and a pair of upper and lower inner flanges 12d.

[0032] The inner wall portion 12a extends in the vertical direction of the vehicle body.

[0033] The upper wall portion 12b and the lower wall portion 12c extend outward in the vehicle width direction from both ends of the inner wall portion 12a.

[0034] The pair of upper and lower inner flanges 12d extend in the vertical direction of the vehicle body from the outer edges of the upper wall portion 12b and the lower wall portion 12c in the vehicle width direction. Each inner flange 12d functions as a flange for joining the inner frame 12 to the outer frame 13.

[0035] 2 to 4, the outer frame 13 has a generally hat-shaped cross section that is shallower than the inner frame 12. The outer frame 13 is disposed in a position facing the outer side of the inner frame 12 in the vehicle width direction. Specifically, an opening of the outer frame 13 is disposed opposite an opening of the inner frame 12.

[0036] The outer frame 13 arranged in this manner has outer wall portions 13a at positions facing the inner wall portions 12a of the inner frame 12. Furthermore, the outer frame 13 has a pair of upper and lower outer flanges 13b at positions facing each inner flange 12d.

[0037] The outer frame 13 is joined with each outer flange 13b abutting against each inner flange 12d.

[0038] As a result, the front side frame 6 has a generally rectangular cross section with a hollow cross section 15, as shown in FIG.

[0039] A pair of front and rear pipe nuts 14 are provided on such a front side frame 6 so as to penetrate the front side frame 6 in the up-and-down direction of the vehicle body 1. Therefore, a pair of front and rear upper through-holes 12e and a pair of front and rear lower through-holes 12f are provided in each of the upper wall portion 12b and the lower wall portion 12c of the front side frame 6, as shown in Figures 3 and 4.

[0040] The pair of front and rear upper through-holes 12e and the pair of front and rear lower through-holes 12f are positioned opposite each other. That is, the insertion holes 12e, 12f are arranged approximately coaxially. The diameter of each of these insertion holes 12e, 12f is set slightly larger than the outer diameter of the pipe nut 14.

[0041] Pipe nut 14 is inserted into each of these insertion holes 12e, 12f from below. As shown in Fig. 5, pipe nut 14 has pipe nut body 14a, joining flange portion 14b, and boss portion 14c.

[0042] As shown in Figures 4 and 6, the pipe nut body 14a has, for example, a generally cylindrical shape with one end closed. A hole formed in the pipe nut body 14a is set as a bolt insertion hole 14d. Furthermore, a female thread portion 14e is formed on the inner circumferential surface of the bolt insertion hole 14d. Note that a bolt 19 (described later) can be threaded into the female thread portion 14e.

[0043] A male thread portion 14f is formed on the outer peripheral surface of the pipe nut body 14a. This male thread portion 14f is formed, for example, from a midpoint toward the tip end (upper end) of the pipe nut body 14a in the longitudinal direction to the base end.

[0044] The joining flange portion 14b is formed at the base end of the pipe nut body 14a. As shown in Figures 2 to 6, this joining flange portion 14b extends in the front-rear direction of the vehicle body along the outer surface of the lower wall portion 12c of the inner frame 12. That is, the shape of the joining flange portion 14b is a rectangle that is long in the front-rear direction of the vehicle body along the lower wall portion 12c.

[0045] When the joining flange portion 14b comes into contact with the outer surface of the lower wall portion 12c, it functions as a first stopper that restricts movement of the pipe nut body 14a in the longitudinal direction.

[0046] Furthermore, the portion of the joining flange portion 14b extending in the front-rear direction of the vehicle body functions as a welded portion to the lower wall portion 12c. That is, the four corners of the joining flange portion 14b can be spot-welded while the joining flange portion 14b is in contact with the outer surface of the lower wall portion 12c. This spot welding allows the joining flange portion 14b to be joined to the plate surface of the lower wall portion 12c.

[0047] Here, it is preferable that the length of the joining flange portion 14b in the vehicle front-rear direction is set to be at least longer than the length of the lower wall portion 12c in the vehicle width direction. By forming it in this manner, the joining flange portion 14b can be brought into contact with the inner flange 12d when the pipe nut 14 rotates about its axis. This allows the joining flange portion 14b to act as a rotation stopper and restrict the rotation of the pipe nut 14.

[0048] 5, the boss portion 14c is formed to protrude downward from the joining flange portion 14b. The boss portion 14c is formed in an annular shape. A seat surface 14g is provided on the protruding surface of the boss portion 14c.

[0049] 4 and 6, the upper surface of the suspension cross member 9 abuts against the seating surface 14g. That is, the seating surface 14g functions as a mounting surface when bolting the suspension cross member 9. For this reason, the seating surface 14g is substantially flat.

[0050] Inside the front side frame 6, the nut 20 is threaded onto the male thread portion 14f of the pipe nut 14 when it is inserted into the lower insertion hole 12f. Note that this threading of the nut 20 is performed before the outer frame 13 is joined to the inner frame 12.

[0051] By threading the nut 20 with the male thread portion 14f, the nut 20 is positioned to abut against the inner surface of the bottom wall portion 12c, and thus functions as a second stopper that restricts movement of the pipe nut body 14a in the longitudinal direction.

[0052] The plate material of the lower wall portion 12c is sandwiched between the nut 20 and the joining flange portion 14b, thereby enabling the nut 20 to firmly fix the pipe nut 14 to the lower wall portion 12c of the front side frame 6.

[0053] In order to properly clamp the lower wall portion 12c, the diameter of the nut 20 is set to be larger than the diameter of the lower insertion hole 12f. In order to achieve such a diameter of the nut 20, it is preferable to use a flange nut as the nut 20.

[0054] By fixing using these joining flange portions 14b and nut 20, the pipe nut body 14a is maintained in a state of being penetrated not only through the lower insertion hole 12f of the lower wall portion 12c but also through the upper insertion hole 12e of the upper wall portion 12b.

[0055] The joining flange portion 14b of the pipe nut 14 fixed in this manner is joined to the lower wall portion 12c by spot welding, as shown in Fig. 6. Furthermore, the tip side of the pipe nut body 14a is inserted into the upper insertion hole 12e and joined to the outer surface of the upper wall portion 12b by arc welding.

[0056] As shown in FIGS. 1, 4, and 6, the suspension cross member 9 has an upper panel 40, a lower panel 41, and a reinforcement 42.

[0057] The upper panel 40 has an open cross-sectional shape that opens downward toward the vehicle body, for example. As shown in Fig. 4, the upper panel 40 has an attachment portion 40a and a side wall portion 40b.

[0058] The mounting portion 40a is disposed at a position facing the lower wall portion 12c. The mounting portion 40a abuts against the bearing surface 14g of the pipe nut 14 and functions as a mounting portion when fixing the suspension cross member 9 to the front side frame 6.

[0059] For this reason, the mounting portion 40a has a pair of front and rear first bolt insertion holes 40c.

[0060] The pair of front and rear first bolt insertion holes 40c are provided at positions facing the respective bolt insertion holes 14d. That is, each first bolt insertion hole 40c and each bolt insertion hole 14d are arranged substantially coaxially.

[0061] The side wall portion 40b extends downward from the outer edge portion of the mounting portion 40a in the vehicle width direction.

[0062] The lower panel 41 is disposed opposite the upper panel 40 with a space therebetween. Second bolt insertion holes 41a are formed in the lower panel 41 at positions opposite each of the first bolt insertion holes 40c. That is, each of the second bolt insertion holes 41a and each of the first bolt insertion holes 40c are disposed substantially coaxially.

[0063] The outer edge portion in the vehicle width direction of the lower panel 41 is bent downward. The lower end portion of the side wall portion 40b of the upper panel 40 is joined to the outer surface in the vehicle width direction of the bent lower panel 41.

[0064] By joining the upper panel 40 and the lower panel 41 in this manner, an internal space is formed in the suspension cross member 9.

[0065] The reinforcement 42 is disposed inside the suspension cross member 9. Specifically, the reinforcement 42 extends along the upper panel 40 in the vehicle width direction.

[0066] The outer end of the reinforcement 42 in the vehicle width direction is in contact with the inner surface of the mounting portion 40a, as shown in Fig. 4. The outer end of the reinforcement 42 in the vehicle width direction is joined to the mounting portion 40a.

[0067] Furthermore, third bolt insertion holes 42a are provided at positions facing the first bolt insertion holes 40c at the joints of the reinforcement 42. That is, the third bolt insertion holes 42a and the first and second bolt insertion holes 40c, 41a are arranged substantially coaxially.

[0068] As shown in FIGS. 4 and 6, a pair of front and rear spacers 43 extend between the reinforcement 42 and the lower panel 41.

[0069] The pair of front and rear spacers 43 are generally cylindrical. A hole formed in each spacer 43 is set as a fourth bolt insertion hole 43a that penetrates in the vertical direction of the vehicle body. That is, the fourth bolt insertion hole 43a of each spacer 43 is disposed generally coaxially with the first to third bolt insertion holes 40c, 41a, 42a.

[0070] The bolts 19 can be inserted into the first to fourth bolt insertion holes 40c, 41a, 42a, and 43a arranged in this manner.

[0071] In the following description, the first to fourth bolt insertion holes 40c, 41a, 42a, and 43a will be collectively referred to as bolt insertion holes H.

[0072] With this configuration, the suspension cross member 9 is fixed to the front side frame 6 by fastening bolts.

[0073] More specifically, when the suspension cross member 9 is fixed to the front side frame 6, the mounting portion 40a abuts against each of the seat surfaces 14g from below.

[0074] Furthermore, each bolt insertion hole H is positioned relative to the bolt insertion hole 14d of each pipe nut 14.

[0075] A bolt 19 is inserted into each positioned pair of bolt insertion hole H and bolt insertion hole 14d from below the bolt insertion hole H. Each bolt 19 is then threaded into the female thread portion 14e of the pipe nut 14. In this way, the suspension cross member 9 is fastened to the front side frame 6.

[0076] An arm support portion 45 is provided on the outer side in the vehicle width direction of the suspension cross member 9 fixed in this manner.

[0077] 1, arm support portion 45 protrudes downward from the bottom surface of lower panel 41 on the outer side in the vehicle width direction. A base end portion of suspension lower arm 50 is journaled on arm support portion 45. This allows the tip end side of suspension lower arm 50 to swing freely in the up and down direction.

[0078] The lower part of a suspension device (not shown) is supported on the outer side in the vehicle width direction of this suspension lower arm 50. Furthermore, a wheel hub (not shown) to which a front wheel is fixed is rotatably supported on the outer side in the vehicle width direction of the suspension lower arm 50.

[0079] According to this embodiment, the fixing structure of the pipe nut 14 comprises a pipe nut body 14a having an internally formed female thread portion 14e and penetrating into the front side frame 6 having a hollow cross section 15; a joining flange portion 14b provided at the base end of the pipe nut body 14a and abutting against the outer surface of the front side frame 6 to restrict longitudinal movement of the pipe nut body 14a; and a nut 20 provided on the pipe nut body 14a and abutting against a surface of the front side frame 6 different from the outer surface of the front side frame 6 against which the joining flange portion 14b abuts, thereby restricting longitudinal movement of the pipe nut body 14a.

[0080] With these configurations, the fixing structure of the pipe nut 14 not only improves production efficiency, but also ensures the mounting rigidity of the pipe nut 14 to the vehicle body frame even when the pipe nut 14 is joined to the vehicle body frame by spot welding.

[0081] That is, in this embodiment, the pipe nut 14 has a pipe nut body 14a that penetrates the front side frame 6. A joint flange portion 14b that abuts against the outer surface of the front side frame 6 to restrict longitudinal movement is provided at the base end of the pipe nut body 14a. Furthermore, a nut 20 is provided on the pipe nut body 14a that abuts against a surface of the front side frame 6 different from the surface that abuts against the joint flange portion 14b to restrict longitudinal movement.

[0082] With these configurations, the fixing structure for the pipe nut 14 of this embodiment can firmly fix the pipe nut 14 to the front side frame 6. This allows the pipe nut 14 to generate sufficient resistance against loads in the prying direction (the direction tilting relative to the central axis) and longitudinal direction that are input to the pipe nut body 14a via the suspension cross member 9 while traveling. Therefore, even if the joining flange portion 14b is joined to the lower wall portion 12c by spot welding, sufficient attachment rigidity of the pipe nut 14 to the front side frame 6 can be ensured.

[0083] Furthermore, spot welding for joining the joining flange portion 14b to the lower wall portion 12c can significantly reduce the amount of spatter (molten metal powder) generated compared to arc welding. This significantly reduces the amount of spatter adhering to the seating surface 14g during welding. Therefore, the welding process of this embodiment, which can use spot welding, does not require the process of attaching and detaching a masking material that protects the seating surface 14g. As a result, the fixing structure of the pipe nut 14 of this embodiment can improve production efficiency.

[0084] Additionally, the nut 20 sandwiches the plate material of the lower wall portion 12c of the front side frame 6 between the joining flange portion 14b inside the front side frame 6. That is, the joining flange portion 14b and the lower wall portion 12c are pressed together by the nut 20. This allows the joining flange portion 14b to be spot-welded to the lower wall portion 12c with an increased contact area between the joining flange portion 14b and the lower wall portion 12c. This improves the welding accuracy during spot welding.

[0085] Furthermore, the tip of the pipe nut body 14a protrudes from the upper wall portion 12b when inserted into the upper insertion hole 12e of the front side frame 6. That is, the tip of the pipe nut body 14a protrudes to a position above and away from the seating surface 14g. This extremely limits the amount of spatter that reaches the seating surface 14g when welding the pipe nut body 14a to the upper wall portion 12b. Therefore, even when the tip of the pipe nut body 14a is firmly joined by arc welding, no masking material is required to protect the seating surface 14g. As a result, the fixing structure of the pipe nut 14 of this embodiment allows the tip of the pipe nut 14 to be fixed by arc welding without reducing production efficiency.

[0086] Furthermore, the joining flange portion 14b has a rectangular shape that is long in the front-to-rear direction of the vehicle body along the bottom wall portion 12c, so that when the joining flange portion 14b abuts against the outer surface of the bottom wall portion 12c, it can accurately restrict the longitudinal movement of the pipe nut body 14a.

[0087] Furthermore, by extending the flange 14b in the longitudinal direction of the vehicle body, it is possible to ensure a sufficient welding area for spot welding at the four corners of the joining flange 14b that are sufficiently distant from the seating surface 14g.

[0088] Furthermore, the length of the joining flange portion 14b in the vehicle front-rear direction is set to be at least longer than the length of the lower wall portion 12c in the vehicle width direction. That is, the joining flange portion 14b has a length that allows it to abut against the inner flange 12d. Therefore, the rotation of the pipe nut 14 can be restricted without adding any new structure to the joining flange portion 14b. By restricting the rotation of the pipe nut 14 in this way, the workability of assembling the pipe nut 14 to the front side frame 6 can be improved.

[0089] Although the setting of the shape of joining flange portion 14b has been described as an example of preventing rotation of pipe nut 14, a notch may be provided in part of the tip of pipe nut body 14a to restrict rotation of pipe nut 14. In this case, the shape of upper insertion hole 12e is changed to a shape that corresponds to the notch in the tip of pipe nut body 14a.

[0090] [Second embodiment]

[0091] A second embodiment of the present invention is shown in Fig. 7. Components similar to those in the first embodiment are given the same reference numerals, and descriptions thereof will be simplified or omitted.

[0092] The nut 20 of the first embodiment sandwiches the lower wall portion 12c of the front side frame 6 between itself and the joining flange portion 14b.

[0093] In contrast, the nut 20 of this embodiment sandwiches the front side frame 6 between itself and the joining flange portion 14b. In this embodiment, the male thread portion 14f is formed, for example, from the tip to the center in the longitudinal direction of the pipe nut body 14a.

[0094] More specifically, on the outside of the front side frame 6, a nut 20 is screwed onto the male thread portion 14f when the male thread portion 14f is inserted into the upper insertion hole 12e.

[0095] By threading the nut 20 with the male thread portion 14f, the nut 20 is positioned in contact with the outer surface of the upper wall portion 12b, thereby restricting the movement of the pipe nut body 14a in the longitudinal direction.

[0096] The nut 20 sandwiches the front side frame 6 between itself and the joining flange portion 14b.

[0097] The front side frame 6 sandwiched in this manner has a spacer 30 inside.

[0098] The spacer 30 is disposed so as to cover the outer periphery of the pipe nut body 14a. That is, the spacer 30 has a generally cylindrical shape that allows the pipe nut body 14a to be inserted therethrough.

[0099] Both ends of the spacer 30 in the vertical direction of the vehicle body are fixed in contact with the inner surfaces of the front side frames 6. It is preferable that at least one of the ends of the spacer 30 is joined to the inner surface of the front side frame 6.

[0100] With this configuration, the fixing structure of this embodiment can firmly fix the pipe nut 14 to the front side frame 6 simply by screwing the nut 20 onto the tip end of the pipe nut body 14a.

[0101] That is, the nut 20 in this embodiment also functions as a joining means for fixing the tip end of the pipe nut body 14a to the upper wall portion 12b. This makes it possible to omit the arc welding process used in the first embodiment. Therefore, the fixing structure of the pipe nut 14 in this embodiment can improve production efficiency compared to the first embodiment.

[0102] In addition, the front side frame 6 is provided with a spacer 30 therein. Such a spacer 30 generates resistance to the pressing force concentrated on the outer surface of the front side frame 6 when the nut 20 is screwed onto the tip of the pipe nut body 14a. Therefore, even if the nut 20 is tightened with a strong force, deformation of the plate material of the front side frame 6 (deformation of the upper wall portion 12b and the lower wall portion 12c) can be prevented. This increases the tightening strength of the nut 20 to the front side frame 6. Therefore, even in a structure in which the pipe nut 14 is fixed from the outside of the front side frame 6 by the nut 20, sufficient attachment rigidity of the pipe nut 14 to the front side frame 6 can be ensured.

[0103] Furthermore, in the case of the fixing structure of this embodiment, it is possible to improve serviceability by omitting spot welding.

[0104] In other words, by eliminating spot welding when joining the joining flange portion 14b to the lower wall portion 12c, the pipe nut 14 can be easily replaced by simply unscrewing the nut 20. This allows the pipe nut 14 to be set as a replaceable part depending on the vehicle model to which it is applied. Therefore, in the case of the fixing structure of this embodiment, elimination of spot welding improves serviceability.

[0105] The other configurations are the same as those in the first embodiment, and therefore the description will be omitted.

[0106] [Third embodiment]

[0107] A third embodiment of the present invention is shown in Fig. 8. Components similar to those in the first and second embodiments are given the same reference numerals, and descriptions thereof will be simplified or omitted.

[0108] In this embodiment, a positioning flange portion 14h is integrally formed as a second stopper at a midpoint on the tip side of the pipe nut body 14a.

[0109] Specifically, as shown in Fig. 8, the positioning flange 14h is provided in an annular shape and protrudes from the outer periphery of the tip side of the pipe nut body 14a. That is, the outer diameter of the positioning flange 14h is set to be larger than the diameter of the upper insertion hole 12e.

[0110] With this setting, when the tip of the pipe nut body 14a is inserted into the upper insertion hole 12e, the upper surface of the positioning flange portion 14h is positioned in contact with the inner surface of the upper wall portion 12b.

[0111] Furthermore, when the positioning flange portion 14h contacts the upper wall portion 12b, the joining flange portion 14b abuts against the outer surface of the lower wall portion 12c.

[0112] The tip of the positioned pipe nut body 14a is joined to the upper wall portion 12b by arc welding. Furthermore, the joining flange portion 14b, which abuts against the outer surface of the lower wall portion 12c, is joined by spot welding.

[0113] In this embodiment, the diameter of the lower insertion hole 12f is set to be slightly larger than the outer diameter of the positioning flange portion 14h, so that when the tip end of the pipe nut body 14a is inserted into the lower insertion hole 12f, the positioning flange portion 14h is inserted without interfering with the lower wall portion 12c.

[0114] This pipe nut 14 has a simpler configuration than the first embodiment and can generate resistance to the prying and longitudinal loads input to the pipe nut body 14a via the suspension cross member 9 while the vehicle is running. In other words, by adopting a fixing structure using the pipe nut 14 of this embodiment depending on the vehicle model, the configuration can be simplified.

[0115] The other configurations are the same as those in the first embodiment, and therefore the description will be omitted.

[0116] The invention described in the above embodiments (first to third embodiments) is not limited to those forms, and various modifications can be made in the implementation stage without departing from the spirit of the invention.

[0117] For example, the fixing structure of the pipe nut 14 described in each of the above embodiments (first to third embodiments) can also be used in the fastening portion between the vehicle body and a seat, or the fastening portion between the vehicle body and a battery case mounted on an electric vehicle.

[0118] Furthermore, the above-mentioned embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining the multiple constituent elements disclosed.

[0119] Furthermore, even if some of the constituent elements are deleted from all the constituent elements shown in the above embodiment, if the stated problem can be solved and the stated effect can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention. [Explanation of symbols]

[0120] 1. Body 2. Engine room 3. Cabin 4. Toe board 5. Foil apron 6. Front side frame 7. Upper side frame 8. Suspension tower 9. Suspension cross member 12···Inner frame 12a...Inner wall part 12b...Top wall part 12c...Lower wall part 12d···Inner flange 12e...Top insertion hole 12f...Bottom insertion hole 13 Outer frame 13a...Outer wall part 13b Outer flange 14···Pipe nut 14a···Pipe nut body 14b: Joint flange portion (first stopper) 14c Boss part 14d Bolt insertion hole 14e Female thread 14f Male thread 14g... Seat 14h... Positioning flange 15...Hollow section 19 volts 20 Nut (second stopper) 30 Spacer 40···Upper panel 40a···Mounting part 40b...Side wall part 40c...First bolt insertion hole 41 Lower panel 41a...Second bolt insertion hole 42 Reinforcement 42a...Third bolt insertion hole 43 Spacer 43a...Fourth bolt insertion hole 45 Arm support 50···Suspension lower arm

Claims

1. a pipe nut body having a female thread formed therein and adapted to penetrate a vehicle body frame having a hollow cross section; a first stopper provided at a base end of the pipe nut body, the first stopper abutting against an outer surface of the vehicle body frame to restrict movement of the pipe nut body in the longitudinal direction; a second stopper that is provided on the pipe nut body and abuts against a surface of the body frame that is different from the outer surface of the body frame that abuts against the first stopper, thereby restricting movement of the pipe nut body in the longitudinal direction.

2. The second stopper is a nut that is screwed onto the outer periphery of the pipe nut body, 2. The pipe nut fixing structure according to claim 1, wherein the second stopper sandwiches the plate material of the vehicle body frame that the first stopper abuts against between the second stopper and the first stopper.

3. The second stopper is a nut that is screwed onto the outer periphery of the pipe nut body, 2. The pipe nut fixing structure according to claim 1, wherein the vehicle body frame is sandwiched between the second stopper and the first stopper.

4. 4. The pipe nut fixing structure according to claim 3, further comprising a spacer provided on the outer periphery of the pipe nut body, the spacer having both ends abutting against the inner surface of the body frame inside the body frame.

5. 5. The pipe nut fixing structure according to claim 1, wherein the first stopper is joined to the outer surface of the vehicle body frame by spot welding.

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