JP4497803B2 - Fastening structure of resin parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fastening part structure of a resin part, and in particular, when an insert member having a fastening receiving part to which a fastened member is pressed and a bottomed nut are integrally fixed to a resin part by insert molding, The present invention relates to a technique for preventing a resin material from entering a screw hole of a bottomed nut.
[0002]
[Prior art]
(a) Fixed to the resin part by insert molding so that the fastening receiving part provided with the bolt insertion hole is exposed on the surface of the resin part and partly embedded in the resin part. (B) disposed on the back side of the fastening receiving portion and corresponding to the bolt insertion hole, and is insert-molded together with the insert member and embedded in the resin part. (C) a fastening bolt is inserted into the bolt insertion hole and screwed into the bottomed nut so that a predetermined fastened member is tightened by the fastening bolt. There is known a fastening part structure for resin parts that is sandwiched between and fixed integrally (see Patent Document 1). FIG. 5 is a cross-sectional view showing an example of such a conventional fastening portion structure. A bottomed nut (cap nut) 104 is disposed corresponding to the bolt insertion hole 102 of the insert member 100, and is made of resin by insert molding. It is configured integrally with the component 106, and the lid portion 108 of the bottomed nut 104 prevents the resin material from entering the screw hole 110.
[0003]
[Patent Document 1]
JP-A-6-120390 (paragraph 12, FIG. 2)
[Patent Document 2]
JP-A-5-205792 (paragraph 11, FIG. 6)
[0004]
[Problems to be solved by the invention]
However, even in such a fastening portion structure, when the resin part 106 is insert-molded by injection molding or the like, a gap is generated between the bottomed nut 104 and the insert member 100, and the screw hole 110 is inserted from the gap. There is a possibility that a resin material may enter. On the other hand, it is conceivable to press-mold the bottomed nut 104 and the insert member 100 to insert-mold, but a space 120 is formed as shown in FIG. 6A by a pressing portion for pressing the bottomed nut 104. For this reason, the shape and strength of the resin part 106 are restricted, and the mold shape is complicated. In addition, as shown in FIG. 6B, when the bottomed nut 104 is disposed at a right angle to the moving direction of the mold (vertical direction in the figure), a separate structure or the like is required. Thus, the mold structure becomes more complicated. In addition, it is conceivable to insert-mold the resin part 106 in a state in which the bolt is screwed to the bottomed nut 104 and fastened integrally with the insert member 100. In addition, in FIG. 6 (b), the head of the bolt protrudes in the lateral direction, so that a gathering type is still necessary.
[0005]
The present invention has been made against the background of the above circumstances. The object of the present invention is to use a bottomed nut as a metal when the insert member and the bottomed nut are integrally fixed to a resin part by insert molding. It is to prevent the resin material from entering the screw hole from between them without pressing the insert member with a mold or the like.
[0006]
[Means for Solving the Problems]
To achieve the above object, the first invention, (a) fastening receiver a bolt insertion hole is provided is exposed on the surface of the resin parts Rutotomoni, back surface part made the resin of the fastening receptacle brought into contact with, and, as part thereof is embedded in the resin component, the insert member which is integrally fixed to the resin part by insert molding, on the back side of the fastening receiving part (b) A bottomed nut disposed in a portion corresponding to the bolt insertion hole and insert-molded with the insert member and embedded in the resin part, and (c) a fastening bolt is the bolt When inserted into the insertion hole and screwed into the bottomed nut, a predetermined member to be fastened is clamped between the fastening receiving portion by the fastening bolt and is in surface contact with the fastening receiving portion Fixed integrally with In the fastening part structure of the fat part, (d) the screw hole opening of the bottomed nut is press-fitted so as to be in close contact with the inner peripheral surface of the bolt insertion hole, and is fixed integrally. A cylindrical fitting protrusion that is hermetically sealed over the circumference is provided integrally, and (e) the protrusion dimension of the fitting protrusion is determined so that the tip does not protrude to the front side of the fastening receiving portion. It is characterized by being.
[0008]
According to a second aspect of the present invention, in the fastening part structure for resin parts according to the first aspect , the protrusion dimension of the fitting protrusion is in the range of 80% to 95% of the wall thickness of the fastening receiving part. To do.
[0009]
According to a third invention, in the fastening part structure of the resin part of the first invention or the second invention, the member to be fastened is an external electrode, and the fastening receiving part is a connection terminal electrically connected to the external electrode. It is characterized by that.
[0010]
【The invention's effect】
In such a resin part fastening part structure, a fitting protrusion is provided in the screw hole opening of the bottomed nut, and is press-fitted so as to be in close contact with the inner peripheral surface of the bolt insertion hole and is integrally fixed. Thus, the entire circumference is hermetically sealed, so that the resin material is surely prevented from entering the screw hole during the insert molding of the resin part. Further, since it is not necessary to press the bottomed nut and the insert member with a mold or a close-up mold, the apparatus is configured simply and inexpensively, and it is not necessary to be fastened integrally with a tightening bolt. The manufacturing man-hours are reduced and the cost is reduced. In addition, since the fitting protrusion is press-fitted so as to be in close contact with the inner peripheral surface of the bolt insertion hole, it is not necessarily necessary to prevent the fitting protrusion from being detached and fixed integrally. Cost is further reduced.
[0011]
In addition, although the technique which press-fits and fixes a nut to a predetermined member is described in the said patent document 2, for example, this is for stopping rotation of a nut and making the fastening operation | work of a fastening bolt easy. There is a difference in background art and problems from the present invention of preventing the intrusion of the resin material, and there is a possibility that a sufficient tightening torque cannot be obtained. Further, in the present invention, since the bottomed nut is originally insert-molded in the resin part, depending on the outer peripheral shape of the bottomed nut, a turning action can be obtained, and there is no reason to apply the technique described in Patent Document 2. .
[0013]
In the second invention, since the protrusion dimension of the fitting protrusion is in the range of 80% to 95% of the thickness of the fastening receiving portion, the deformation of the fitting protrusion due to deformation of the fastening receiving portion when the fastening bolt is tightened. There is no fear that the tip may come into contact with the fastened member, and the fastened member can be firmly fixed by bringing the fastened member into surface contact with the fastening receiving portion. For example, when electrically connected as in the third invention, high energization performance In addition, there is little possibility that the tightening will be loosened due to vibration or deformation and the connected state will be impaired. In addition, since it is press-fitted to more than 80% of the thickness of the fastening receiving part, it is possible to prevent the bottomed nut from coming out of the bolt insertion hole or being displaced when insert molding of resin parts such as injection molding. Is done.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The present invention has a relatively high voltage or current value, such as a DC-DC converter, an inverter, or other device that converts power, and is particularly connected to a connection terminal provided in a case (resin part) of an electric device that supplies power. On the other hand, it is preferably applied to a fastening part structure for connecting an external electrode connected to an external power source or the like, but it may be used only for transmitting and receiving relatively weak electrical signals, etc., and also applied to a fastening part structure other than energization. Can be done.
[0015]
For the resin parts, an insulating synthetic resin material having a low electrical conductivity, such as PPS (polyphenylene sulfide) or PPS alloy, is preferably used, and it is desirable to form by injection molding, and a reinforcing material such as glass fiber is used. A mixed composite reinforced resin is preferably used, but other synthetic resin materials may be employed. For the insert member having the fastening receiving portion, for example, a metal material having high electrical conductivity is preferably used.
[0016]
As the bottomed nut, a cap nut provided with a hemispherical lid is preferably used, and a fitting protrusion can be provided by cutting and removing the outer peripheral portion on the opening side. Various forms can be employed, such as cutting a female screw on the peripheral surface, or integrally fixing a closing member to an opening at one end of a nut through which a screw hole passes.
[0017]
The outer shape of the bottomed nut is preferably a square shape such as a hexagon that can be locked by engagement with a resin part. For example, serrations are provided on the outer peripheral surface of the fitting projection, or the fitting projection It is also possible to make the outer shape of the bottomed nut into a perfect circle by providing a plurality of meshing teeth at the tip of the nut and engaging it with the insert member by caulking to the outer peripheral side. . You may make it provide rotation engagement parts, such as a serration and a meshing tooth, in the fitting protrusion of a square-shaped bottomed nut.
[0018]
Fitting projection is being press-fitted into bolt insertion hole, fitting the engagement projection with press-fitted into the bolt insertion holes, such as the tip may be retained by caulking, various aspects Is possible.
[0019]
Protruding dimension of the fitting protrusion, it is not to desired to the second range 80% to 95% of the thickness of the fastening receiving portion as in the invention.
[0020]
In the second invention, the protrusion dimension of the fitting protrusion is 80% or more of the wall thickness of the fastening receiving part, but if it is less than this, the bottomed nut is inserted into the insert member during insert molding of the resin part by injection molding or the like. There is a possibility of slipping out of the bolt insertion hole or misalignment. If it is more than 95%, it depends on the material of the insert member. However, when the bolt is tightened, the fastening receiving portion is deformed and the tip of the fitting projection comes into contact with the fastened member. The fastening strength may be impaired.
[0021]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a case where the present invention is applied to a fastening portion 12 of a case 10 of a power converter such as a DC-DC converter and an inverter mounted on an automobile. The case 10 corresponds to a resin part and has an electrical conductivity. Is made of a low-insulating synthetic resin material, specifically, a PPS fiber reinforced resin in which glass fibers are mixed in PPS (polyphenylene sulfide). The fastening portion 12 is for electrically connecting the external electrode 18 connected to an external power source (battery or the like) to the connection terminal 16 of the insert member 14 made of a metal material by fastening bolts 20. The connection terminal 16 and the external electrode 18 have a flat plate shape, and are provided with bolt insertion holes 16h and 18h through which the fastening bolts 20 are inserted. The connection terminal 16 constituted by a part of the insert member 14 corresponds to a fastening receiving portion, and the external electrode 18 corresponds to a member to be fastened. 1A shows a state before the external electrode 18 is attached, and FIG. 1B shows a state where the external electrode 18 is attached. FIG. 2 is a schematic view showing an example of the case 10 provided with the fastening portion 12 of FIG.
[0022]
The insert member 14 is integrated with the case 10 simultaneously with the molding of the case 10 by insert molding so that the connection terminal 16 is exposed on the outer surface of the side wall 10a of the case 10 and a part thereof is embedded in the case 10. It is fixed to. Further, a cap nut 22 as a bottomed nut is disposed on the back side of the connection terminal 16 and corresponding to the bolt insertion hole 16h, and is insert-molded together with the insert member 14 so as to be integrated into the side wall 10a of the case 10. It is buried underground. The cap nut 22 is integrally provided with a hemispherical lid portion 24 by welding or the like, and one opening portion is closed, and a screw hole opening portion on the opposite side thereof has a bolt insertion hole 16h. A cylindrical fitting protrusion 26 that is press-fitted so as to be in close contact with the inner peripheral surface and is integrally fixed is integrally protruded, and the fitting protrusion 26 is press-fitted into the bolt insertion hole 16h. The case 10 is insert-molded in a state in which the space between the connection terminals 16 is sealed over the entire circumference.
[0023]
The tightening bolt 20 is screwed into the screw hole 28 of the cap nut 22 so that the external electrode 18 is pressed so as to be in surface contact with the connection terminal 16 to be fastened integrally and electrically connected. . The cap nut 22 has a normal hexagonal outer peripheral shape, and the fitting protrusion 26 is not only press-fitted and fixed in the bolt insertion hole 16 h of the connection terminal 16, but also the outer peripheral portion and the case 10. Rotation is reliably prevented by the engagement, and the external bolt 18 can be firmly fixed to the connection terminal 16 so that the current-carrying performance is not impaired by the vibration of the automobile by tightening the tightening bolt 20 with high tightening strength. .
[0024]
The projecting dimension t of the fitting projection 26 is within a range of 80% to 95% of the thickness of the connection terminal 16, that is, the plate thickness of the insert member 14, and even if the tightening bolt 20 is tightened with high tightening strength, There is no fear that the tip of the fitting protrusion 26 abuts on the external electrode 18 due to the deformation of the connection terminal 16. Moreover, since it press-fits to 80% or more of the thickness of the connection terminal 16, the cap nut 22 may come off from the bolt insertion hole 16h of the connection terminal 16 or be displaced at the time of insert molding of the case 10 by injection molding. Well prevented.
[0025]
In such a structure of the fastening portion 12 of this embodiment, the fitting protrusion 26 is provided in the screw hole opening of the cap nut 22 and is press-fitted into the bolt insertion hole 16h to be integrally fixed. Since the space between the connection terminal 16 and the connection terminal 16 is hermetically sealed, the resin material enters the screw hole 28 from between the cap nut 22 and the connection terminal 16 during the insert molding of the case 10. Is reliably prevented. In addition, since it is not necessary to press the cap nut 22 and the connection terminal 16 with a mold or a close-up mold, the molding apparatus is configured simply and inexpensively and needs to be fastened together in advance using bolts. Therefore, the number of manufacturing steps is reduced and the case 10 is manufactured at low cost.
[0026]
In this embodiment, since the moving direction (mold clamping, mold opening direction) of the molding die is the vertical direction in FIG. 1 and the axis of the cap nut 22 is the horizontal direction, the cap nut 22 is connected to the connection terminal 16. In the case of pressing and fixing, it is necessary to provide a gathering die using a cam mechanism or the like, which further complicates the molding apparatus.
[0027]
On the other hand, in the present embodiment, the fitting protrusion 26 is press-fitted so as to be in close contact with the inner peripheral surface of the bolt insertion hole 16h and is integrally fixed. The manufacturing cost is further reduced as compared with the case of doing so.
[0028]
Further, since the protrusion dimension t of the fitting protrusion 26 is in the range of 80% to 95% of the thickness of the connection terminal 16, it is fitted by elastic deformation of the connection terminal 16 when the tightening bolt 20 is tightened. There is no fear that the tip of the projection 26 abuts on the external electrode 18, and the external electrode 18 can be brought into surface contact with the connection terminal 16 and firmly fixed. There is little possibility that the connection is loosened due to loosening.
[0029]
Moreover, since it press-fits to 80% or more of the thickness of the connection terminal 16, the cap nut 22 may come off from the bolt insertion hole 16h of the connection terminal 16 or be displaced at the time of insert molding of the case 10 by injection molding. Well prevented.
[0030]
Next, another embodiment of the present invention will be described. In the following embodiments, parts common to those in the above embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.
[0031]
FIGS. 3A and 3B are diagrams showing another example of the fitting structure between the cap nut 22 and the connection terminal 16, respectively, and neither has a female screw at the tip of the fitting projection 26. The cylindrical portions 30 and 32 are provided to be extended, and are bent to the outer peripheral side by caulking to be integrally fixed to the connection terminal 16, and the caulking is allowed at the peripheral edge of the opening of the bolt insertion hole 16h. A tapered surface and counterbore are provided. In this case, press fit coupled with the cap nut 22 is Ru is fixed to more firmly connect the terminal 16.
[0032]
4 (a) and 4 (b) are diagrams showing an example of a bottomed nut used in place of the cap nut 22, and the bottomed nut 40 of FIG. 4 (a) has a thin end portion 42 due to forging or the like. In this case, a female screw is formed by cutting or the like on the inner peripheral surface of the bottomed cylindrical member provided to provide a screw hole 44, and the thin tip portion 42 is used as a fitting projection. Without using forging, it is also possible to cut a pilot hole for the screw hole 44 by cutting with a drill or the like, or to remove the outer peripheral portion of the tip portion 42 by cutting to make it thin. Further, the bottomed nut 50 of (b) is provided with a screw hole 56 by forming a female screw by cutting or the like on the inner peripheral surface of a cylindrical member whose both ends 52 and 54 are thinned by forging or the like. In addition, the lid member 58 is integrally fixed to the one end portion 52 side by welding or press-fitting and closed, and the other end portion 54 is used as a fitting projection. Also in this case, without using a forging process, a pilot hole for the screw hole 56 can be processed by cutting with a drill or the like, or the outer peripheral portion of the other end 54 can be removed by cutting to make it thinner. Is possible.
[0033]
As mentioned above, although the Example of this invention was described in detail based on drawing, these are one embodiment to the last, and this invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.
[Brief description of the drawings]
1A and 1B are cross-sectional views showing a fastening part structure according to an embodiment of the present invention, in which FIG. 1A shows a state before a fastening member is attached, and FIG. 1B shows a state where a fastening member is attached.
2 is a schematic diagram showing an example of a case of a power conversion device including the fastening portion structure of FIG.
FIGS. 3A and 3B are cross-sectional views showing another example of a fitting structure between a bottomed nut and a fastening receiving portion. FIGS.
4A and 4B are cross-sectional views showing another example of a bottomed nut.
FIG. 5 is a cross-sectional view showing an example of a conventional fastening portion structure.
FIGS. 6A and 6B are cross-sectional views showing an example of a fastening part structure when insert molding is performed by pressing a bottomed nut against a fastening receiving part in order to prevent intrusion of a resin material.
[Explanation of symbols]
10: Case (resin part) 12: Fastening portion 14: Insert member 16: Connection terminal (fastening receiving portion) 16h: Bolt insertion hole 18: External electrode (fastened member) 20: Fastening bolt 22: Cap nut (existing) Bottom nut) 26: fitting protrusion 40, 50: bottomed nut 42: tip portion (fitting protrusion) 54: other end portion (fitting protrusion)

Claims (3)

Rutotomoni fastening receiver a bolt insertion hole is provided is exposed on the surface of the resin component, the rear surface of the fastening receiving portion is brought into contact with said resin component, and, partially embedded in the resin parts An insert member fixed integrally to the resin part by insert molding,
A bottomed nut that is disposed on the back side of the fastening receiving portion and corresponding to the bolt insertion hole, is insert-molded together with the insert member, and is embedded in the resin part;
And a fastening bolt is inserted into the bolt insertion hole and screwed into the bottomed nut, whereby a predetermined member to be fastened is clamped between the fastening receiving portion and the fastening bolt. In the fastening part structure of the resin part that is integrally fixed in a state of surface contact with the fastening receiving part,
A cylindrical fitting protrusion that is hermetically sealed over the entire circumference by being press-fitted into the screw hole opening of the bottomed nut so as to be in close contact with the inner peripheral surface of the bolt insertion hole. Part is provided integrally,
And the protrusion dimension of this fitting protrusion is determined so that the front-end | tip may not protrude to the front side of the said fastening receiving part. The fastening part structure of the resin parts characterized by the above-mentioned. The protruding dimension of the fitting protrusion is fastened part structure of the resin component according to claim 1, characterized in that in the range of 80% to 95% of the wall thickness of the fastening receptacle. The fastening part structure for a resin part according to claim 1 or 2, wherein the fastening member is an external electrode, and the fastening receiving part is a connection terminal electrically connected to the external electrode.

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