JPH11311219A - Resin mold fixing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To positively prevent loosening of a bolt for fastening flanges different in the coefficients of expansion and contraction while reducing the number of part items and improving impact resistance. SOLUTION: In a structure provided with a first flange 11 and a second flange 21 made of resin, with these first and second flanges 11, 21 vertically overlapped and bolt-fastened to fix resin molds 10, 20 to a fitting object 30, the first flange 11 is formed of a hard resin material, and the second flange 21 is formed of a soft resin material. The first flange 11 is provided with a through hole 11a pierced with a bolt 41, and a fixed seat 11b integrally formed around the through hole 11a using the same hard resin material and piercing the second flange 21 abutting the fitting object 30. The second flange 21 is provided with a receiving hole 21a pierced with the bolt 41 and the fixed seat 11b of the first flange 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for fixing a resin molded product, for example, a cover of an electric junction box mounted on a vehicle, and more particularly, to an expansion coefficient while reducing the number of parts and improving impact resistance. The present invention relates to a fixing structure for a resin molded product that can reliably prevent a bolt and a nut that fasten flanges having different shrinkage rates from loosening.

[0002]

2. Description of the Related Art The applicant of the present invention has proposed, in Japanese Patent Application Laid-Open No. Hei 10-42424, a fixing structure for a resin molded product for the purpose of reducing the number of parts and improving impact resistance. FIG. 7 is a cross-sectional view of a main part showing a fixing structure of the resin molded product.

In FIG. 1, reference numeral 100 denotes an electric connection box, which is used for connection between wire harnesses routed in a vehicle, and includes a relay (not shown) in an upper cover 110 and a lower cover 120 which are resin molded products. It is configured to house an electric circuit composed of a fuse, a bus bar wiring board, and the like.

[0004] The upper cover 110 and the lower cover 120 are provided with a first flange 111 and a second flange 121 which are vertically overlapped, respectively. First flange 111
Is formed of a hard resin material (a resin material in which glass is mixed with polypropylene).
It is formed of a soft resin material (a resin material obtained by mixing talc in polypropylene). The first and second flanges 111 and 121 are provided with insertion holes 111a and 121a having the same diameter, respectively, which coincide with each other when they are vertically overlapped.

When the electric connection box 100 is fixed to a bracket (mounting object) 130 in the vehicle, the insertion holes 111a, 121a of the first and second flanges 111, 121 are used.
Is aligned with the insertion hole 130a of the bracket 130 in the vehicle, the bolt 141 is inserted through the through holes 111a, 121a, 130a, and the bolt 141 and the nut 142 are fastened on the back side of the bracket 130.

According to the fixing structure of the resin molded article, since the first flange 111 located on the upper side is formed of a hard resin material, the first flange 111 is made of metal for protecting the flange from the fastening force of the bolt 141 and the nut 142. Colors can be removed from the configuration. Also, since the lower second flange 121 is formed of a soft resin material,
Good shock absorption due to vibration and the like.

[0007]

In the above-mentioned structure for fixing a resin molded product, the hard resin material and the soft resin material forming the first and second flanges 111 and 121 are mainly made of polypropylene. Although there is no problem, if the first and second flanges 111 and 121 are formed of resin materials having different expansion rates and contraction rates, the bolt 141 and the nut 142 are loosened due to a change in temperature or humidity. There was a problem.

For example, the first flange 111 is formed of nylon, which is a hard resin material, and the second flange 12 is formed of nylon.
It is assumed that No. 1 is formed of polypropylene which is a soft resin material. The second flange 121 made of polypropylene having a small expansion rate and a small shrinkage rate has a small change in dimension due to the influence of temperature or humidity, but the first flange 111 made of nylon having a large expansion rate and a shrinkage rate has a small influence of temperature or humidity. The dimensions change greatly.

Therefore, as shown in FIG. 7, in a fixing structure in which the first and second flanges 111 and 121 are simply overlapped and fastened with bolts and nuts, the first flange 11
When 1 shrinks in the direction of its thickness, there is a problem that bolts and nuts are loosened.

In order to prevent the bolts and nuts from being loosened, it is conceivable that the bolts and nuts are excessively tightened in advance. In this case, however, the second flange 121 formed of a soft resin material has an excessive fastening force. There was a problem that it was damaged by receiving.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made to reduce the number of parts and improve the impact resistance, and to reduce the loosening of bolts and nuts for fastening flanges having different expansion rates and contraction rates. An object of the present invention is to provide a resin molded product fixing structure that can be reliably prevented.

[0012]

In order to achieve the above object, a resin molded product fixing structure of the present invention has a first flange and a second flange made of resin, and these first and second flanges are connected to each other. By bolting up and down,
In the structure in which the resin molded product is fixed to the mounting object, the first flange is formed of a hard resin material,
The second flange is formed of a soft resin material, and the first flange is formed integrally with the insertion hole through which the bolt is inserted by the same hard resin material around the insertion hole, and penetrates the second flange. The second flange is provided with a receiving hole through which the bolt and the fixing seat of the first flange are inserted (claim 1).

[0013] According to this configuration, the fastening force of the bolt (or nut) is applied only to the fixing seat of the first flange formed of the hard resin material, and is applied to the second flange formed of the soft resin material. Will not join. That is, the bolt (or nut) fixes the first and second flanges made of different materials to the object to be mounted, but only the first flange is fastened structurally.

Therefore, when the first flange is formed of a resin material having a large expansion rate and a high contraction rate, the loosening of the bolt (or nut) can be reliably prevented by excessively tightening the bolt (or nut) in advance. . In this case, since the fastening force of the bolt (or the nut) is applied only to the fixing seat of the first flange, the second flange formed of the soft resin material is not damaged by an excessive fastening force.

Further, since the fixing seat of the first flange formed of the hard resin material receives the fastening force of the bolt (or the nut), the metal collar for protecting the flange can be omitted from the configuration. Further, since the second flange is formed of a soft resin material, the shock absorption due to vibration or the like is improved.

Preferably, the fixing seat of the first flange is a cylindrical body having the same inner diameter as the insertion hole, or the fixing seat of the first flange is provided around the insertion hole. And two or more blocks (claims 2 and 3).

When the fixing seat of the first flange is a cylindrical body, the strength of the fixing seat which receives the fastening force of the bolt (or nut) can be increased, and the fixing seat of the first flange can be two or more. In the case of the block body described above, it is possible to save material while maintaining sufficient strength of the fixed seat.

Preferably, the fixing seat of the first flange is two or more blocks provided around the insertion hole, and the receiving hole of the second flange is a circle corresponding to the outer shape of the bolt. An arc-shaped bolt receiving portion and a fixed seat receiving portion corresponding to the outer shape of each fixed seat of the first flange are provided (claim 4).

According to such a configuration, when the bolt is welded to the mounting object, the bolt can be easily positioned in the receiving hole of the second flange.

That is, as described above, when the fixing seat of the first flange is a cylindrical body (for example, a cylindrical shape), the second flange is provided with a receiving hole corresponding only to the outer shape of the fixing seat. become.

The receiving hole in this case also serves as a bolt insertion hole, but is naturally a hole larger than the diameter of the bolt.
When the bolt is welded to the mounting object and only the second flange is inserted through the bolt (for example, when the lower cover is temporarily fixed to the mounting object first, and then the upper cover is assembled to the lower cover), It is conceivable that the bolt moves freely in the receiving hole, so that the fixing seat of the first flange cannot be fitted into the receiving hole later.

Therefore, if an arc-shaped bolt receiving portion corresponding to the outer shape of the bolt is provided in the receiving hole of the second flange as described above, the bolt can be easily positioned in the receiving hole. But the fixed seat of the first flange,
It can be easily fitted into the receiving hole.

Preferably, two or more engaging portions for pressing against the bolt are integrally formed on the inner wall of the receiving hole of the second flange. According to such a configuration, the locking portion integrally formed in the receiving hole of the second flange presses against the bolt, and the bolt can be accurately and easily positioned in the receiving hole.

Preferably, when the first and second flanges are bolted together, a projection which presses against the surface of the second flange is integrally formed on the back surface of the first flange with the same hard resin material. (Claim 6).

According to such a configuration, the second flange is prevented from rattling while using the fastening force of the bolt (or nut) to prevent the second flange formed of the soft resin from being damaged. be able to.

That is, in the fixing structure of the resin molded product of the present invention, the fastening force of the bolt (or nut) is applied only to the fixing seat of the first flange formed of the hard resin material,
The second flange formed of the soft resin material is sandwiched between the first flange and the mounting object without receiving the fastening force of the bolt (or nut).

Since the second flange does not receive the fastening force of the bolt (or nut) as described above, it is possible to prevent the second flange formed of the soft resin material from being damaged. In such a case, the second flange may be loose.

Therefore, if the above-mentioned protrusion is provided on the back surface of the first flange, the protrusion comes into pressure contact with the surface of the second flange when the first and second flanges are bolted, and The rattling of the second flange can be prevented without applying excessive fastening to the flange.

[0029]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fixing structure of a resin molded product according to an embodiment of the present invention.
First, a fixing structure for a resin molded product according to the first embodiment of the present invention will be described. FIG. 1 is a perspective view showing a structure for fixing a resin molded product according to the first embodiment of the present invention. FIG. 2A is a rear view of the first flange shown in FIG.
(B) is sectional drawing which shows the state which bolted the 1st and 2nd flange to the bracket.

In FIG. 1, in the present embodiment, the resin molded product is an upper cover 10 and a lower cover 20 that constitute the electric connection box 1, and the upper cover 10 and the lower cover 20 are provided on a bracket (not shown) provided on a vehicle (not shown). 30) with bolts. The upper cover 10 and the lower cover 20 are provided with a first flange 11 and a second flange 21 which are vertically overlapped, respectively.

The first flange 11 is formed of a hard resin material (for example, nylon) and has an insertion hole 11a. A bolt 41 welded to the bracket 30 is inserted through the insertion hole 11a.

As shown in FIGS. 1 and 2A, a cylindrical fixing seat having the same inner diameter as the insertion hole 11a is formed of the same hard resin material around the insertion hole 11a on the back surface of the first flange 11. 11b is integrally formed. As shown in FIG. 2B, the fixed seat 11b is
1 and comes into contact with the bracket 30.

As shown in FIG. 2A, a plurality of hemispherical projections 11c are symmetrically protruded from the same hard resin material around the fixed seat 11b on the back surface of the first flange 11. I have.

In FIG. 1, the second flange 21 is formed of a soft resin material (for example, polypropylene), and has a circular receiving hole 21a having substantially the same diameter as the fixing seat 11b of the first flange 11. In this receiving hole 21a,
The bolt 41 and the fixing seat 11b are inserted.

In such a configuration, the upper cover 1
When fixing the lower cover 20 (electric connection box 1) to the bracket 30 in the vehicle, the upper cover 10 and the lower cover 20 shown in FIG.
Assemble the electric junction box 1. As a result, the first and second flanges 11 and 21 are vertically overlapped.

Next, the insertion hole 11a of the first flange 11
A bolt 41 welded to the bracket 30 is inserted through the cylindrical fixed seat 11b, and a nut 42 is screwed into a tip of the bolt 41 protruding from the surface of the first flange 11,
The two are concluded. As a result, the upper cover 10 and the lower cover 20 (the electric connection box 1) are fixed to the bracket 30 in the vehicle.

According to the resin molded product fixing structure of the present embodiment having the above-described configuration, the fastening force of the nut 42 is reduced by the fixing seat 11b of the first flange 11 formed of a hard resin material.
Only the second flange 21 made of a soft resin material. That is, although the nut 42 fixes the first and second flanges 11 and 21 made of different materials to the bracket 30, only the first flange 11 is fastened structurally.

Therefore, when the first flange 11 is formed of a resin material having a high expansion rate and a high contraction rate, the nut 42 can be reliably prevented from being loosened by excessively tightening the nut 42 in advance. In this case, since the fastening force of the nut 42 is applied only to the fixing seat 11b of the first flange 11, the second flange 21 formed of a soft resin material is not damaged by an excessive fastening force.

Further, since a plurality of projections 11c are provided on the back surface of the first flange 11, each projection 11c is provided on the front surface of the second flange 21 when the first and second flanges 11 and 21 are bolted. To prevent breakage of the second flange 21 while preventing rattling of the second flange 21.

Further, since the fixing seat 11b of the first flange 11 formed of the hard resin material receives the fastening force of the nut 42, the metal collar for protecting the flange can be omitted from the configuration. In addition, since the second flange 21 is formed of a soft resin material,
Good shock absorption due to vibration and the like.

Next, a fixing structure for a resin molded product according to the second embodiment of the present invention will be described. FIG. 3 is a perspective view showing a fixing structure for a resin molded product according to the second embodiment of the present invention. 4 (a) is a rear view of the first flange shown in FIG. 3, FIG. 4 (b) is a sectional view taken along the line AA of FIG. 3, and FIG. 4 (c).
FIG. 4 is a sectional view taken along the line BB of FIG. 3.

In FIGS. 3 and 4 (a), on the back surface of the first flange 11, a fixing seat 12b composed of four blocks is disposed in a substantially cross shape with the insertion hole 11a as a center. The surface of each fixing seat 12b facing the insertion hole 11a has an arc shape corresponding to the outer shape of the bolt 41.

On the other hand, the second flange 21 has a bolt receiving portion 2 composed of four arc surfaces corresponding to the outer shape of the insertion hole 11a of the first flange 11 (that is, the outer shape of the bolt 41).
A substantially cross-shaped receiving hole 22 constituted by 2a and four fixed seat receiving portions 22b corresponding to the outer shape of each fixed seat 12b of the first flange 11 is provided.

Further, the inner walls of the respective arc surfaces forming the bolt receiving portions 22a are respectively raised toward the center, so that four claw-shaped engaging portions 22c which are pressed against four positions of the bolt 41 are integrally formed. It is.

According to such a configuration, when the first and second flanges 11 and 21 are bolted to the bracket 30, as shown in FIG.
It is applied only to each fixed seat 12b of the first flange 11 formed of a hard resin material, and the loosening of the nut 42 can be prevented as in the first embodiment.

Further, as shown in FIG. 4C, the bolt 41 is accurately and easily positioned in the receiving hole 22 by the bolt receiving portion 22a and the locking portion 22c forming the receiving hole 22 of the second flange 21. be able to.

As a result, even when the lower cover 20 shown in FIG. 3 is temporarily fixed to the bracket 30 first, and then the upper cover 10 is assembled to the lower cover 20, each fixing seat 12 b of the first flange 11 is fixed to the second flange 12. 21 can be easily fitted into the receiving hole 22, and the assembling workability can be improved.

Further, since the fixing seat of the first flange 11 is a fixing seat 12b composed of four blocks, each of the fixing seats 12b has sufficient strength to withstand the fastening force of the nut 42, and the material of the material is reduced. Savings can be achieved.

Next, a fixing structure for a resin molded product according to the third embodiment of the present invention will be described. FIG. 5 is a perspective view showing a structure for fixing a resin molded product according to the third embodiment of the present invention. 6 (a) is a rear view of the first flange shown in FIG. 5, FIG. 6 (b) is a cross-sectional view taken along line CC of FIG. 5, and FIG. 6 (c).
FIG. 6 is a sectional view taken along line DD of FIG. 5.

In FIG. 5 and FIG. 6A, a fixing seat 13b composed of two blocks is provided on the back surface of the first flange 11 on both sides of the insertion hole 11a. The surface of each fixing seat 13b facing the insertion hole 11a has an arc shape corresponding to the outer shape of the bolt 41.

On the other hand, the second flange 21 has a bolt receiving portion 2 composed of two arc surfaces corresponding to the outer shape of the insertion hole 11a of the first flange 11 (that is, the outer shape of the bolt 41).
There is provided a receiving hole 23 constituted by 3a and two fixed seat receiving portions 23b corresponding to the outer shape of each fixed seat 13b of the first flange 11.

The inner wall of each arc surface forming the bolt receiving portion 23a is raised toward the center, so that two claw-shaped locking portions 23c which press against two places of the bolt 41 are integrally formed. It is.

According to such a configuration, when the first and second flanges 11 and 21 are bolted to the bracket 30, as shown in FIG.
It is applied only to each fixing seat 13b of the first flange 11 formed of a hard resin material, and the loosening of the nut 42 can be prevented as in the second embodiment (see FIG. 4B).

As shown in FIG. 6C, a bolt receiving portion 23a and a locking portion 23c forming a receiving hole 23 of the second flange 21 are similar to those of the second embodiment (FIG. 4).
(See (c)), the bolt 41 can be accurately and easily positioned in the receiving hole 23.

As a result, even when the lower cover 20 shown in FIG. 5 is temporarily fixed to the bracket 30 first, and then the upper cover 10 is assembled to the lower cover 20, each of the first flanges 11 is similar to the second embodiment. Fixed seat 13b
Can be easily fitted into the receiving hole 23 of the second flange 21, and the assembling workability can be improved.

Further, by fixing the fixing seat of the first flange 11 to the fixing seat 13b composed of two blocks, each of the fixing seats has sufficient strength to withstand the fastening force of the nut 42, as in the second embodiment. The material can be saved while being provided on the seat 13b.

The structure for fixing the resin molded product of the present invention is as follows.
The present invention is not limited to the first to third embodiments. For example, in each of the embodiments described above, the resin molded product is the upper cover 10 and the lower cover 20 of the electric connection box. However, the present invention is not limited to this, and the fixing structure of the present invention can be applied to various resin molded products. .

The fixed seat 1 on the first flange 11
The shapes of 1b, 12b, and 13b are not limited to the cylindrical shape in the first embodiment or the two or more blocks in the second and third embodiments.
The shape can be changed to various shapes as long as it is integrally formed of the same hard resin material around the insertion hole 11a on the back side and penetrates the second flange 21 to abut on the mounting object.

Similarly, the receiving holes 21a, 22 and 23 in the second flange 21 are also fixed seats 11b, 12b and 1
3b can be changed to various shapes.

Further, in the second and third embodiments, the bolt receiving portions 22a, 23a constituting the receiving holes 22, 23 of the second flange 21 are provided with claw-shaped locking portions 22c, 23.
Although c is formed, a configuration in which only the locking portion is provided without providing the bolt receiving portions 22a and 23a may be adopted. In addition to this, the locking portion is not limited to a claw shape, and can be changed to various shapes (for example, a projection shape) that can be pressed against the bolt.

[0061]

As described above, according to the resin molded product fixing structure of the present invention, the bolts for fastening the flanges having different expansion rates and shrinkage rates while reducing the number of parts and improving the impact resistance are provided. Looseness of the nut can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a fixing structure of a resin molded product according to a first embodiment of the present invention.

2A is a rear view of a first flange shown in FIG. 1, and FIG. 2B is a cross-sectional view showing a state where the first and second flanges are bolted to a bracket.

FIG. 3 is a perspective view showing a fixing structure of a resin molded product according to a second embodiment of the present invention.

4 (a) is a rear view of the first flange shown in FIG. 3, FIG. 4 (b) is a sectional view taken along line AA of FIG. 3, and FIG. 4 (c) is a line BB of FIG. It is sectional drawing.

FIG. 5 is a perspective view showing a fixing structure of a resin molded product according to a third embodiment of the present invention.

6 (a) is a rear view of the first flange shown in FIG. 5, FIG. 6 (b) is a sectional view taken along the line CC of FIG. 5, and FIG. 6 (c) is a line DD of FIG. It is sectional drawing.

FIG. 7 is a cross-sectional view of a main part showing a conventional structure for fixing a resin molded product.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric connection box 10 Upper cover (resin molded product) 11 First flange 11a Insertion hole 11b, 12b, 13b Fixed seat 11c Projection 20 Lower cover (resin molded product) 21 Second flange 21a, 22, 23 Receiving hole 22a, 23a Bolt receiving portion 22b, 23b Fixed seat receiving portion 22c, 23c Locking portion 30 Bracket (object to be mounted) 41 Bolt 42 Nut

Claims (6)

[Claims] 1. A structure in which a resin molded product is fixed to an object to be mounted by having a first flange and a second flange made of resin, the first and second flanges being vertically overlapped and bolted. The first flange is formed of a hard resin material, and the second flange is formed of a soft resin material. The first flange has an insertion hole through which the bolt is inserted, and the same around the insertion hole. A fixing seat that is integrally formed of a hard resin material and penetrates the second flange and abuts on the mounting object; a fixing seat of the bolt and the first flange is inserted into the second flange; A fixing structure for a resin molded product, wherein a receiving hole is provided. 2. The fixing structure for a resin molded product according to claim 1, wherein the fixing seat of the first flange is a cylindrical body having the same inner diameter as the insertion hole. 3. The resin-molded product fixing structure according to claim 1, wherein the fixing seat of the first flange is two or more blocks provided around the insertion hole. 4. The receiving hole of the second flange includes an arc-shaped bolt receiving portion corresponding to the external shape of the bolt and a fixed seat receiving portion corresponding to the external shape of each fixed seat of the first flange. Item 4. A fixing structure for a resin molded product according to Item 3. 5. The fixing structure for a resin molded product according to claim 3, wherein two or more locking portions for pressing against the bolt are integrally formed on the inner wall of the receiving hole of the second flange. 6. A projection formed on the back surface of the first flange and integrally formed of the same hard resin material when the first and second flanges are bolted together. 5. The fixing structure for a resin molded product according to any one of the above items 5.