JP6943712B2 - Case nut structure - Google Patents

Description

The present invention relates to a case nut structure in which a nut is held against a base material such as a vehicle body frame among fasteners composed of bolts and nuts.

Conventionally, as a case nut structure of this type, as shown in Patent Document 1, a bracket (board) is spot-welded to one surface of a body having a through hole through which a bolt is inserted, and the bracket (board) and a base material are spot-welded. The nut is held non-rotating in the gap between the nut and the nut, and the head of the nut is projected from the nut engagement hole of the bracket (board) to prevent the nut from falling and the nut engages with the nut during electrodeposition coating. A case nut structure is disclosed that prevents the nut from sticking to the hole and allows the bolt to be screwed in while the nut is held in an appropriate position.

Further, Patent Document 2 has a case nut structure in which a nut is movably stored inside a case body (board) to be welded to the body, and the nut is insert-molded on the nut body and its outer surface. A case nut structure is disclosed which is composed of a resin insulating member and can prevent the nut from sticking to the body because the nut body is insulated by the insulating member during the electrodeposition coating process.

Jikkenhei 3-114617 Japanese Unexamined Patent Publication No. 2016-217423

In the case nut structure shown in Patent Document 1 and Patent Document 2, when the electrodeposition coating of the vehicle body is dried, the nut movably housed inside the substrate is fixed to the hole wall of the nut through hole of the substrate. It was devised to prevent.

By the way, in this kind of bolt / nut fastener, a case nut structure that can prevent the nut from sticking by improving the fluidity of the paint at the time of electrodeposition coating is desired. FIG. 11 is a plan view showing a reference example of a case nut structure in which a recess for electrodeposition liquid flow is further formed on the hole wall of the nut through hole of the substrate. For simplification of the illustration, only the shape of the nut through hole (hexagonal shape) of the substrate and the positional relationship of the hexagon nut penetrating the nut through hole are shown. FIG. 11A shows a state in which the central shaft 100a of the nut 100 and the center 101a of the through hole 101 substantially match. FIG. 3B shows an interference state between the nut and the electrodeposition liquid flow recess 102 when the nut 100 is rotated from the state shown in FIG. FIG. 3C shows a state in which the nut 100 is offset with respect to the through hole 101 during electrodeposition coating because the through hole 101 is formed to have a smaller diameter than the nut 100 but has a larger diameter.

As shown in FIG. 11, in order to improve the fluidity of the electrodeposited liquid, a recess 102 for flowing the electrodeposited liquid is formed on the wall surface 101b facing the nut side wall 100b of the through hole 101. As shown in FIG. (B), when a bolt (not shown) is rotated when the bolt is fastened, the nut 100 also rotates within the allowable rotation range, and the top 100c of the nut 100 licks the flow recess 102, so that the nut top If the nut is crushed, the nut may rotate with the bolt and the bolt may not be tightened securely. In this case, the substrate itself having the crushed nut or the through hole 100 in the broken state must be replaced. For example, when the case nut structure is provided in an internal space such as a rocker of a vehicle body frame, there is a problem that the replacement and repair work becomes complicated.

Further, as shown in FIG. 11C, if the shape of the through hole 101 is simply offset according to the outer diameter of the nut 100, the side wall 100b of the nut 100 and the through hole 101 are formed during electrodeposition coating. There is a risk that the inner wall surface 101b will come into line contact with the inner wall surface 101b and stick to the inner wall surface 101b during drying.
Further, if an attempt is made to improve the flow of the electrodeposited liquid by increasing the offset amount of the through hole 101, the nut top 100c can easily lick the wall surface 101b of the through hole 101, as in the case shown in FIG. 11B. Bolt fastening may not work.
Further, as shown in Patent Document 2, if the insulating member is set on the outer surface of the nut, there is a problem that the cost is high and the weight of the nut itself is increased.

In view of the above, it is an object of the present invention to provide a case nut structure having a simple structure, which can prevent licking of through holes, improve the flow of electrodeposited liquid, and avoid sticking of nuts.

In a case nut structure in which a polygonal nut is freely inserted and set in a through hole of a substrate mounted on a vehicle body in order to achieve the above object, the through hole is a portion facing the top of the nut. A plurality of recesses are formed in which the wall surface of the through hole is recessed so that the gap with the top is wider than other parts, and the adjacent recesses are formed in a shape connected by an arc close to the side wall surface of the nut. The case nut structure is used.

According to the above configuration, the expansion recess is formed so as to expand outward from the center of the through hole so as to expand more than other portions. Therefore, the gap between the top of the nut and the enlarged recess of the through hole is enlarged more than other parts, and the electrodeposition liquid easily escapes from the enlarged recess of the through hole during electrodeposition coating, and electrodeposition is applied to the through hole. There is an advantage that the liquid is less likely to collect.

Further, in the through hole, by making the wall surface shape of the through hole connecting the recesses into an arc shape close to the nut side wall surface, the side wall of the nut held on the substrate and the arc wall surface of the through hole come into point contact. As a result, the side wall of the nut is less likely to adhere to the arc wall surface of the through hole during drying after electrodeposition coating.
Here, the polygonal nut may be a hexagon nut as shown in FIG. 11, a square nut as shown in FIGS. 5 to 9, or a pentagonal nut (not shown). Even with these polygonal shapes, the through holes are formed in a substantially similar shape to match the polygonal shape, and an enlarged recess is formed at the corner facing the nut top of the through hole, and the wall surface of the through hole connecting the enlarged recesses is formed. The shape may be an arc wall surface that is close to the nut side wall surface.

Moreover, even if the nut rotates to lick the through hole when the bolt is fastened, the rotation locus of the nut that crosses the arcuate surface of the through hole is shown by hatching in, for example, a square nut as shown in FIG. Since it will increase significantly, it will be difficult for the nut to lick the through hole. Therefore, it is possible to provide a case nut structure having a simple structure, which can prevent licking of the through hole, improve the flow of the electrodeposited liquid, and further avoid sticking of the nut.

It is a top view which shows the rear frame part of the vehicle which is embodiment of this invention. It is a side sectional view of FIG. FIG. 1 is a cross-sectional view taken along the line AA of FIG. It is an exploded perspective view of the tip part of a trailing arm. It is a perspective view which shows the case nut structure of this embodiment. It is sectional drawing of the case nut structure. It is a top view which shows the behavior of a square nut and the positional relationship with a through hole. It is a top view which shows the positional relationship with the through hole at the time of rotation of a square nut. It is a top view which shows the positional relationship at the time of offset of a nut with respect to a through hole. It is a plan view which shows the positional relationship between a hexagon nut and a through hole which is another embodiment. FIG. The state of interference between the nut and the through hole, and FIG. 3C shows the positional relationship between the nut and the through hole at the time of nut offset. It is a plan view showing the positional relationship between the hexagon nut and the through hole, which is a reference example. FIG. The state of interference between the nut and the through hole, and FIG. 3C shows the positional relationship between the nut and the through hole at the time of nut offset.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a rear frame portion of the vehicle according to the present embodiment. FIG. 2 is a side sectional view of FIG. 1, and FIG. 3 is a sectional view taken along the line AA of FIG. In FIG. 1, the arrow Fr indicates the front in the traveling direction of the vehicle 1.

As shown in FIG. 1, the vehicle 1 includes a vehicle body 2 made of sheet metal and wheels 4 suspended from the vehicle body 2 by a suspension 3, and the inside of the vehicle body 2 is a vehicle interior 5. The vehicle body 2 is arranged between the left and right rockers 9 formed at the lower end edges of the left and right side walls 8 forming the left and right side surfaces of the vehicle interior 5 and extending in the front-rear direction of the vehicle body 2, and the left and right rockers 9. The left and right front side members 10 extending in the front-rear direction of 2, the left and right rear side members 12 connected to the rear end of each rocker 9 so as to extend rearward, and the left and right front sides extending in the width direction of the vehicle body 2. The front cross member 13 that connects the rear ends of the members 10 and the front ends of the left and right rear side members 12 to each other, and the middle portions of the left and right rear side members 12 that extend in the width direction of the vehicle body 2 are connected to each other. It includes an intermediate cross member 14 to be connected and a rear cross member 15 for connecting the rear ends of the left and right rear side members 12 to each other.

As shown in FIG. 3, the rocker 9 includes a rocker outer panel 25 and a rocker inner panel 26 facing each other in the width direction of the vehicle body 2, and a rocker reinforcing panel 27 sandwiched between them to improve the rigidity of the rocker 9. have. The longitudinal cross section of the rocker outer panel 25 has a hat shape that opens toward the inside of the vehicle body 2, and the longitudinal cross section of the rocker inner panel 26 has a hat shape that opens toward the outside of the vehicle body 2. The cross section of each part of the rocker 9 in the longitudinal direction is formed into a hollow closed cross section structure by the panels 25 and 26. Then, as shown in FIG. 4, a case nut structure 40 is provided inside the rockin panel 26 to support a pivot shaft 38 that pivotally supports the tip bush 39 of the trailing arm 37 of the suspension 3.

The suspension 3 has a box-shaped bracket 35 connected to the rocker inner panel 26 and the rear side member 12 at the rear end of the rocker 9, and is arranged below each rear side member 12 and extends in the front-rear direction of the vehicle body 2 to cross. A pivot shaft 38 that pivotally supports the left and right trailing arms 37, which are connected to each other by the member 36, and the rear end side of the trailing arm 37 to the bracket 35 via a bush 39 so that the rear side of the trailing arm 37 can rotate up and down. A shock absorber 39 installed on each trailing arm 37 and a rear side member 12, and a coil spring (not shown) are provided.

The bush 39 at the front end of the trailing arm 37 includes an outer cylinder 39a coupled to the front end of the trailing arm 37, an inner cylinder 39b through which the bolt 38, which is the pivot shaft, penetrates, and the inner cylinder 39b and the outer cylinder 39b. It is composed of a cylindrical elastic material 39c interposed between the cylinder 39a. As shown in FIG. 4, the bolt is used as the pivot shaft 38, and the tip of the bolt 38 is screwed and fastened to the nut 53 of the case nut structure 40 in a closed space such as inside the rocker 9.

As shown in FIG. 5, the case nut structure 40 includes a substrate 51 that is spot-welded to the inside of the rockin panel 26 of the rocker 9, and a nut 53 that is movably inserted and set in the through hole 52 of the substrate 51. I have. The substrate 51 is formed on a flat plate-shaped main body 51a having a through hole 52, and on the inner walls of the side walls 51b, 51c and the inner panel 26 of the rocker 9 in which both front and rear ends of the main body 51a are bent in a crank shape to hold the nut 53. It is formed in a hat shape in a plan view from the welding flanges 51d and 51e to be spot-welded.

The nut 53 is a nut with a flange, and is formed by integrally forming a polygonal tubular (for example, a square tubular shape in this embodiment) nut head 54 and a flange 55 formed on the lower surface thereof. The flange 55 is formed in a disk shape, and the flange diameter thereof is formed to be larger than the diameter of the through hole 52 of the substrate 51 so that the flange 55 does not come out from the through hole 52 outward in the vehicle width direction. There is. The flange thickness is set thinner than the heights of the side walls 51b and 51c of the substrate 51.

The nut head 54 is formed, for example, in the shape of a square cylinder, and the tops 54a of the four corners thereof are slightly formed in an R shape. The side wall 54b connecting the adjacent tops 54a is a well-known nut formed in a flat shape. Then, as shown in FIG. 6, the nut head 54 is set to a height that penetrates the through hole 52 in a state of being set in the through hole 52 of the substrate 51 and protrudes outward. A female screw is formed in the bolt hole 54c of the nut head 54 so as to be screwed with the male screw 38a engraved on the bolt 38.

7 to 9 are simplified views of the behavior of the nut 53 with respect to the through hole 52 of the substrate 51 when the bolts and nuts are fastened. First, the shape of the through hole 52 will be described with reference to these figures. The through hole 52 is formed in a substantially similar quadrangular shape that is slightly larger than the polygonal (for example, square in the present embodiment) nut head 54 in plan view. A gap 57 is formed between the nut head 54 and the hole wall of the through hole 52 to allow the electrodeposition liquid to flow.

Of the hole wall of the through hole 52, the through hole 52 is enlarged at the corner portion of the nut head 54 facing the top 54a so that the gap between the through hole 52 and the nut head 54 is larger than that of the other portion 57. An enlarged recess 58 is formed. That is, there are a plurality of enlarged recesses 58 in which the wall surface of the through hole 52 is recessed so that the gap between the nut top 54a and the nut top 54a is wider than the other portions 57 at the portion facing the nut top 54a, according to the number of the nut tops 54a. It is formed.

The expansion recess 58 is recessed in an arc shape, and is formed to a depth at which the expansion recess 58 and the nut top 54a do not come into contact with each other even if the nut top 54a is close to the expansion recess 58 by offset as shown in FIG. Further, as shown by the alternate long and short dash line in FIG. 7, the enlarged recess 58 has a depth located outside the rotation locus 59 when rotated around the axial center 53a of the nut 53 that coincides with the center 52a of the through hole 52. It is recessed so far.

Further, the hole wall of the through hole 52 connecting the adjacent enlarged recesses 58 is not formed linearly with the side wall 54b of the nut head 54, but when the side wall 54b of the nut head 54 is substantially flat, the nut It is formed in an arc shape 60 that approaches the side wall 54b side of the head 54. That is, the hole wall of the through hole 52 is an arc wall surface 60 in which the hole wall portion connecting the enlarged recess 58 is close to the side wall 54b side of the nut head 54.

The minimum gap 57 between the arc wall surface 60 and the side wall 54b of the nut head 54 is the minimum assembly clearance when the nut 53 is assembled.

In the above configuration, when the tip bush 39 of the trailing arm 37 is attached to the bracket 35 side inside the vehicle width direction of the rocker 9, the bush 39 of the trailing arm 37 is set in the bracket 35 and the bolt 38 is installed from the inside in the vehicle width direction. Is inserted into the through hole of the bracket 35, screwed into the nut 53 of the case nut structure 40 in the inner space of the rocker 9, and bolted.

At this time, in the case nut structure 40, the substrate 51 is fixed to the inside of the rocker 9 by spot welding, but the nut 53 is held by the substrate 51 to have a retaining structure. Therefore, at the time of electrodeposition coating of the vehicle body, the case nut structure 40 is electrodeposited while holding the nut 53.

At this time, since the gap between the nut top 54a and the expansion recess 58 of the through hole 52 is larger than that of the other portion 57, the electrodeposition liquid can easily escape from the expansion recess 58 of the through hole 52 during electrodeposition coating. , The electrodeposition liquid is less likely to collect in the through hole 52.

Moreover, in the through hole 52 of the substrate 51, the arc wall surface 60 connecting the enlarged recesses 58 has an arc shape close to the nut side wall 54b, and therefore, as shown in FIG. The point contact 61 with the arc wall surface 60. Therefore, the side wall 54b of the nut 53 is less likely to adhere to the wall surface of the through hole 52 during drying after electrodeposition coating.

Further, even if the nut 53 rotates to lick the through hole 52 when the bolt is fastened, the rotation locus 59 of the nut 53 that exceeds the arc wall surface 60 of the through hole 52 is large as in the region 62 shown by hatching in FIG. Since the number increases, it becomes difficult for the nut 53 to lick the through hole 52.

In particular, in the case of the square nut 53, the through hole 52 also has a square shape, and as compared with the case of the hexagon nut, the region 62 between the arc wall surface 60 of the through hole 52 and the rotation locus 59 of the nut 53 (in the hatching of FIG. 8). Since the area shown) becomes large, there is an effect that the nut 53 is more difficult to lick the through hole 52.

Further, when the nut 53 is offset, the side wall 54b of the nut head 54 and the arc wall 60 of the through hole 52 make point contact, so that the side wall 54b of the nut 53 is in contact with the arc wall 60 of the through hole 52 during drying after electrodeposition coating. It becomes difficult to stick to.

FIG. 10 shows an embodiment in which a hexagon nut is used instead of the square nut. Also in this embodiment, the through hole 52 is formed into a substantially hexagonal shape having a similar shape slightly larger than that of the hexagonal nut head 54 in a plan view. A gap 57 is formed between the side wall 54b of the nut head 54 and the hole wall surface (arc wall surface 60) of the through hole 52 to allow the electrodeposition liquid to flow.

Of the hole wall of the through hole 52, in the portion corresponding to the top portion 54a of the nut head 54, the through hole 52 is enlarged so that the gap between the through hole 52 and the nut head 54 is larger than that of the other portion 57. A recess 58 is formed. The expansion recess 58 is recessed in an arc shape, and is formed to a depth at which the expansion recess 58 and the nut top 54a do not come into contact with each other even if the nut top 54a is close to the expansion recess 58 by offset as shown in FIG. 10 (c). ing. Further, the expansion recess 58 is recessed to a depth located outside the rotation locus 59 when the nut 53 is rotated about the axis center 53a of the nut 53 that matches the center 52a of the through hole 52.

Then, as shown in FIG. 10A, when the nut center shaft 53a and the center of the through hole 52 are aligned with each other, the minimum gap 57 capable of penetrating the nut 53 through the through hole 52 is an arc. It is formed between the wall surface 60 and the side wall 54b of the nut head 54.

FIG. 10B shows an interference state between the nut and the through hole when the nut rotates. In this state, the arc wall surface 60 connecting the enlarged recesses 58 has an arc shape approaching the nut side wall 54b. Therefore, the side wall 54b of the nut 53 comes into point contact 61 with the arc wall 60 of the through hole 52, and the side wall 54b of the nut 53 is less likely to stick to the arc wall 60 of the through hole 52 during drying after electrodeposition coating. Further, when the bolt is fastened, the nut top 54a abuts on the arc wall surface 60 of the through hole 52 and is less likely to be deformed, making it difficult to lick the hole wall of the through hole 52.

FIG. 10C shows the positional relationship between the nut 53 and the through hole 52 at the time of nut offset. When the nut 53 is offset, the side wall 54b of the nut head 54 and the arc wall surface 60 of the through hole 52 make point contact 61, so that the nut side wall 54b is less likely to adhere to the wall surface of the through hole 52 during drying after electrodeposition coating. ..

As shown in the above embodiment, in a case nut structure in which a polygonal nut is freely inserted and set in a through hole of a substrate attached to a vehicle body, the through hole is a portion facing the top of the nut. A plurality of recesses are formed in which the wall surface of the through hole is recessed so that the gap with the nut top is wider than other parts, and the adjacent recesses are connected by an arc close to the side wall surface of the nut. It is formed.

Therefore, since the gap between the top of the nut and the recess of the through hole is larger than that of other parts, the electrodeposition liquid can easily escape from the recess of the through hole during electrodeposition coating, and the electrodeposition liquid is less likely to collect in the through hole. There is an advantage.

Further, in the through hole, by making the wall surface shape of the through hole connecting the recesses into an arc shape close to the nut side wall surface, the side wall surface of the nut and the arc wall surface of the through hole come into point contact. During drying after electrodeposition coating, the side wall surface of the nut is less likely to adhere to the arc wall surface of the through hole.

Moreover, even if the nut rotates to lick the through hole when the bolt is fastened, the arc wall surface of the through hole makes it difficult for the nut to lick the through hole. Therefore, with a simple structure, there are excellent effects such as preventing licking of the through hole, improving the flow of the electrodeposited liquid, and further avoiding sticking of the nut.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made within the scope of the present invention. For example, in the above embodiment, the case nut structure suitable for electrodeposition coating is adopted for the case nut installed in the rocker of the vehicle body frame, but the present invention is not limited to this and is applied to the case nuts of various parts of the vehicle. Can be done. Furthermore, it can be applied to all kinds of case nut structures, not limited to electrodeposition coating.

1 Vehicle 2 Body 3 Suspension 4 Wheels 5 Chassis 8 Side wall 9 Rocker 10 Front side member 12 Rear side member 13 Front cross member 14 Midway cross member 15 Rear cross member 25 Rocker outer panel 26 Rocker inner panel 27 Rocker reinforcement panel 35 Bracket 36 Cross Member 37 Trailing arm 38 Pivot shaft 39 Bush 40 Case nut structure 39a Outer cylinder 39b Inner cylinder 39c Elastic material 51 Substrate 51a Main body 51b, 51c Side wall 51d, 51e Welded flange
52 Through hole 53 Nut 54 Nut head 54a Nut top 54b Nut side wall 54c Bolt hole 55 Flange 57 Gap 58 Enlarged recess 59 Rotational locus 60 Arc wall surface 61 Point contact

Claims (1)

A case nut structure provided in the closed space of the vehicle body to be electrodeposited and for holding a nut fastened to a bolt inserted into the closed space from a hole formed in the panel forming the closed space. Therefore, the substrate is attached to the panel, and the nut with a polygonal flange arranged between the substrate and the panel is movable in the through hole formed in the substrate and does not come out of the through hole. The through hole is formed with a plurality of recesses in which the wall surface of the through hole is recessed at a portion facing the nut top so that the gap with the nut top is wider than other portions. The hole wall connecting the matching recesses is formed in an arc shape close to the side wall surface of the nut, and the electrodeposition liquid can flow between the hole wall and the side wall surface of the nut, and the closed space. A case nut structure characterized in that a gap is formed to allow fastening of the bolt inserted inside and the nut.

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