JP2011239600A - Electrical connection box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical connection box having a new structure capable of surely injecting a connection nut to the electrical connection box and fixing the connection nut with excellent position accuracy to assemble the electrical connection box with the connection nut.SOLUTION: On an inner peripheral surface 32 of a nut housing part 22 formed in an electrical connection box body 12, injection ribs 34 extending to a bottom surface 36 of the nut housing part 22 in the injection direction of a connection nut 26 are continuously formed in the circumferential direction of the nut housing part 22, and in the bottom surface 36, a scrap plastic housing recess 42 spreading around the injection ribs 34 is formed.

Description

  The present invention relates to an electrical connection box mounted on an automobile or the like, and more particularly to an electrical connection box to which a nut to which a connection bolt is screwed is attached.

  Conventionally, as a structure for connecting a connection terminal (external terminal) of an external circuit to an internal circuit of an electrical connection box, a structure in which a connection portion of the internal circuit and the external terminal are fastened with a bolt and a nut is known. For example, in the electrical junction box described in Japanese Patent Application Laid-Open No. 2000-209743 (Patent Document 1), a connection nut is attached to an electrical junction box body in which a bus bar constituting an internal circuit is incorporated. Then, by overlapping the terminal portion formed on the bus bar and the connection terminal of the external wiring on the fastening surface of the connection nut, and screwing the connection bolt inserted through them into the connection nut and tightening, The connection terminals of these external wirings are electrically connected to the terminal portions formed on the bus bar.

  By the way, the connection nut in such an electrical junction box is required to be accurately and reliably positioned and attached to the electrical junction box body. Precise and reliable positioning of the connection nut with respect to the electrical junction box body is to prevent the connection nut from falling off before tightening the connection bolt, and to screw and tighten the connection nut when tightening the connection bolt. It is also important for positioning the connection portion between the connection terminal of the external wiring and the terminal portion formed on the bus bar after the connection bolt is tightened. Therefore, in the conventional electrical junction box, a nut housing portion is provided in the electrical junction box body made of synthetic resin, and the connecting nut is fixedly attached by press-fitting the connecting nut into the nut housing portion. .

  However, when the connecting nut is press-fitted into the nut accommodating portion, there is a problem that it is difficult to stably obtain the press-fitting fixing force due to a dimensional error or a difference in thermal expansion between the two members.

  A nut for connecting to the nut housing part is provided by providing a press-fitting rib extending in the press-fitting direction on the inner peripheral surface of the nut housing part, and absorbing variations in dimensions due to dimensional errors, thermal expansion differences, etc. by deformation of the press-fit ribs, etc. It may be possible to stabilize the fixing force. However, such a press-fitting rib may be scraped and scraped when the connecting nut is press-fitted, and the connecting nut is inclined when the shavings are sandwiched between the bottom surface of the nut housing portion and the connecting nut. The problem is that the fixing position accuracy of the connecting nut is greatly lowered due to the floating or floating.

JP 2000-209743 A

  The present invention has been made in the background of the above-mentioned circumstances, and the problem to be solved is that the connecting nut can be securely press-fitted and assembled with excellent positioning accuracy with respect to the electric connection box body. The object is to provide an electrical junction box having a novel structure.

  According to a first aspect of the present invention, a connection nut is press-fitted in an axial direction with respect to a nut housing portion formed in an electric junction box body made of synthetic resin, and the connection nut is placed on the bottom surface of the nut housing portion. In the electrical junction box assembled in a state where the axial end surfaces are overlapped, a press-fitting rib extending in the press-fitting direction of the connecting nut on the inner peripheral surface of the nut housing part and reaching the bottom surface of the nut housing part A plurality of the nut housing portions are formed in the circumferential direction, and a resin waste housing recess extending around the press-fitting rib is formed on the bottom surface of the nut housing portion.

  According to the electrical junction box having the structure according to this aspect, the nut can be positioned and fixed by the press-fitting rib in the accommodated state in the nut accommodating portion. Furthermore, dimensional variations due to dimensional errors, thermal expansion differences, and the like can be absorbed by deformation of the press-fit ribs, so that a stable fixing force can be obtained.

  And the resin waste which arises at the time of the press injection of a nut can be accommodated by the resin waste accommodation recess formed in the circumference of the press-fitting rib in the bottom of the nut housing part. As a result, it is possible to prevent problems such as resin waste being sandwiched between the bottom surface of the nut housing portion and the nut, and the nut being lifted or inclined from the nut housing portion.

  Furthermore, in order to accommodate the protrusion part from the nut of a connection bolt in the center part of the bottom face of a nut accommodating part, it was necessary to provide the accommodation hole of the connection bolt in a comparatively wide range. Therefore, a support surface that supports the nut is configured by the remaining peripheral edge, and it is difficult to ensure a sufficient support area. However, according to this aspect, by forming the resin waste housing recess for each press-fitting rib in a shape surrounding the press-fitting rib, the area of the support surface is advantageously secured, and the support strength of the nut is secured. It was possible to achieve both the prevention of resin waste biting in a highly compatible manner.

  A second aspect of the present invention is the one described in the first aspect, wherein the volume of the resin waste accommodating recess is 1/2 to 1 times the volume of the press-fitting rib.

  According to this aspect, while ensuring a sufficient volume to accommodate the resin waste generated when the nut is press-fitted, the resin waste storage recess becomes larger than necessary and the area of the bottom surface of the nut storage portion is reduced. By avoiding this, the support strength of the nut can be maintained. In this embodiment, preferably, the volume of the resin waste accommodating recess is made substantially equal to the volume of the press-fitting rib in consideration of the case where all the press-fitting ribs are shaved.

  According to a third aspect of the present invention, in the first or second aspect, an opening of the resin waste containing recess is covered with the connecting nut. In this way, since the scattering of the resin waste accommodated in the resin waste accommodating recess is suppressed, problems such as poor electrical contact and poor physical fitting caused by the scattered resin waste entering. Can be prevented.

  According to the present invention, since the press-fitting rib is formed on the inner peripheral surface of the nut housing portion, it is possible to absorb a dimensional error, a difference in thermal expansion, and the like, and the connection nut is stably stored in the nut housing portion. Can be press-fitted and retained. Then, by forming the resin waste accommodating recess around each press-fitting rib on the bottom surface of the nut accommodating portion, it occurs at the time of press-fitting while suppressing a decrease in the area of the bottom surface supporting the connecting nut and ensuring sufficient support strength. Resin waste can be accommodated in the resin waste accommodating recess to prevent the connection nut from being lifted or inclined from the nut accommodating portion.

The disassembled perspective view of the electrical-connection box as one Embodiment of this invention. The enlarged view of the A section in FIG. The top view of the nut accommodating part formed in the electrical junction box shown in FIG. FIG. 4 is a cross-sectional view showing a fixed state of the connection plate of part A shown in FIG. 2, corresponding to the IV-IV cross section in FIG. 3.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an electrical junction box 10 as an embodiment of the present invention. The electrical junction box 10 is configured to include a box body 12 having a block shape made of synthetic resin. The box body 12 has a pair of mounting recesses 14a and 14b that open upward. Then, connection plates 16a and 16b made of thick metal plates are fitted and fixed in the mounting recesses 14a and 14b.

  A plurality of recesses 20 are formed in the overlapping surface 18 constituting the bottom surfaces of the mounting recesses 14a and 14b. The recess 20 is shown in FIGS. FIG. 4 shows the connection plate 16a in a fixed state. The plurality of recesses 20 have the same shape as each other, and have a bottomed stepped recess shape that opens only on the overlapping surface 18 side. In the recess 20, a nut housing portion 22 is formed on the overlapping surface 18 side, and a bolt housing hole 24 continuous from the nut housing portion 22 is formed on the opposite side of the overlapping surface 18.

  The nut accommodating portion 22 has a concave shape that opens on the overlapping surface 18 with an opening shape corresponding to the connecting nut 26. The connection nut 26 in the present embodiment has a rectangular block shape, and the nut accommodating portion 22 has a rectangular opening shape corresponding to the connection nut 26. Further, the connecting nut 26 has an axial direction in the through direction (vertical direction in FIG. 4) of a screw hole 28 penetrating in the center. And the depth dimension of the nut accommodating part 22 is made substantially equal to the axial direction dimension of the connecting nut 26. The opening edge 30 of the nut housing portion 22 is tapered so that the connection nut 26 can be easily inserted.

  A plurality of press-fitting ribs 34 are integrally formed on the inner peripheral surface 32 of the nut housing portion 22. The press-fitting rib 34 projects from the inner peripheral surface 32 inward of the nut housing part 22 and is a protrusion that extends in the press-fitting direction (vertical direction in FIG. 4) of the connecting nut 26. It is formed over substantially the entire length reaching the bottom surface 36 in the depth direction. The cross-sectional shape of the press-fit rib 34 is preferably a cross-sectional shape that tapers in the protruding direction from the inner peripheral surface 32. In the present embodiment, the cross-sectional shape is a semicircular cross-section. In addition, in the extending direction of the press-fitting rib 34, the tip portion 38 on the overlapping surface 18 side gradually protrudes from the inner peripheral surface 32 from the overlapping surface 18 side in order to facilitate press-fitting of the connecting nut 26. It is supposed to be an inclined surface that becomes larger.

  A plurality of such press-fitting ribs 34 are formed at predetermined intervals in the circumferential direction of the nut housing portion 22 on the inner peripheral surface 32. The number of the press-fitting ribs 34 is appropriately set in consideration of the required fixing strength and the like, and is not particularly limited, but is preferably a nut housing portion 22 formed from a plurality of surfaces. In the inner peripheral surface 32, at least one is preferably formed for each surface. In particular, in the present embodiment, a total of eight press-fitting ribs 34 are formed on each one of the four inner peripheral surfaces 32.

  Further, the bottom surface 36 of the nut housing portion 22 protrudes inward from the inner peripheral surface 32 and is formed continuously over the entire circumference of the nut housing portion 22. The protruding dimension of the bottom surface 36 from the inner peripheral surface 32 is set so as not to overlap the screw hole 28 of the connecting nut 26 accommodated in the nut accommodating portion 22.

  Then, on the bottom surface 36, a resin waste housing recess 42 is formed for each press-fit rib 34 around the base end portion 40 on the opposite side of the distal end portion 38 of each press-fit rib 34. The resin waste accommodating recess 42 is formed so as to surround the press-fitting rib 34. The opening 43 of the resin waste accommodating recess 42 is formed only on the bottom surface 36. Further, the plurality of resin waste accommodating recesses 42 are formed independently of each other without communicating with other resin waste accommodating recesses 42. The shape of the resin waste accommodating recess 42 is not particularly limited, but in the present embodiment, it is a semicircular cross section surrounding the press-fitting rib 34.

  Note that the volume of the resin waste accommodating recess 42 is appropriately set in consideration of the amount of resin waste generated when the press-fitting rib 34 is scraped when the connecting nut 26 is inserted, and preferably the press-fitting rib. It is set within a range of 1/2 to 1 times the volume of 34, and more preferably, it is set to 1 time of the press-fitting rib 34 in consideration of the case where all of the press-fit ribs 34 are cut. By doing so, it is possible to effectively secure the area of the bottom surface 36 and to effectively maintain the support strength of the connecting nut 26 while securing a sufficient volume to accommodate the resin waste.

  A bolt housing hole 24 is formed in the center of the bottom surface 36. The bolt receiving hole 24 has a rectangular shape and has a bottomed concave shape opened to the bottom surface 36, and is formed with a depth dimension larger than a protruding dimension from a connecting nut 26 of a connecting bolt 48 described later.

  In the electrical junction box 10 having such a structure, as shown in FIG. 1, connection nuts 26 are fitted into the respective nut accommodating portions 22. At the time of this fitting, the connecting nut 26 is press-fitted in the axial direction while pressing the press-fitting rib 34 toward the bottom surface 36 of the nut housing portion 22. As a result, the connecting nut 26 is press-fitted and fixed in the nut housing portion 22 with the axial end face 44 superimposed on the bottom face 36.

  Then, with the connection nut 26 being press-fitted and fixed in the nut housing portion 22, the connection plates 16a and 16b are fitted into the mounting recesses 14a and 14b, respectively, so that the bolts inserted through the connection plates 16a and 16b are inserted. The hole 46 is overlapped with the screw hole 28 of the connecting nut 26. Then, the fixing bolts 48 are inserted into the respective bolt insertion holes 46 and screwed into the connection nuts 26, whereby the connection plates 16a and 16b are fixed in a state of being fitted into the mounting recesses 14a and 14b, respectively. . When the fixing bolt 48 is screwed into the connecting nut 26, the inner peripheral surface 32 of the nut housing portion 22 is formed in the same polygonal shape as the connecting nut 26, so that the connecting nut 26 is prevented from being rotated. ing.

  In addition, on the surface 50 of the connection plates 16a and 16b, connection terminals for external wiring and electrical parts (not shown) are superimposed as necessary, and the fixing bolts 48 are inserted into these connection terminals. Thus, the connection plates 16a and 16b are fixed in a conductive state. Further, as shown in FIG. 4, the protruding portion of the fixing bolt 48 from the connecting nut 26 is accommodated in the bolt accommodating hole 24.

  According to the electrical junction box 10 having such a structure, the connection nut 26 can be press-fitted and fixed by the press-fit rib 34 in a state of being accommodated in the nut accommodating portion 22. As a result, the connection nut 26 can be prevented from falling off, and the handleability of the box body 12 is improved. Then, by absorbing dimensional errors and thermal expansion differences with the press-fitting ribs 34, the positioning state of the connecting nut 26 can be maintained with high accuracy, and the connecting plates 16a, 16b, etc. can be assembled more stably. I can do it.

  Further, when the connection nut 26 is press-fitted and fixed to the nut housing portion 22, the press-fit rib 34 may be scraped by the connection nut 26, and the resin waste generated at that time is stored in the resin waste storage recess 42. I can do it. Thereby, it is possible to avoid the biting of resin waste, and the connecting nut 26 can be accurately positioned on the same plane without protruding from the overlapping surface 18 of the mounting recesses 14a and 14b. As a result, the connection plates 16a and 16b can be stably fitted into the mounting recesses 14a and 14b and fixed with bolts.

  Since the plurality of resin waste accommodating recesses 42 are independently formed around the press-fitting ribs 34, the area of the bottom surface 36 that supports the connection nut 26 can be effectively ensured. Thereby, the further reduction of the area of the bottom face 36 with the bolt insertion hole 46 opened at the center can be reduced, and the connecting nut 26 can be stably supported on the entire circumference of the outer peripheral portion.

  Further, the plurality of resin waste accommodating recesses 42 are independently opened only on the bottom surface 36, and the axial end face 44 of the connecting nut 26 is in a press-fitted and fixed state to the nut accommodating portion 22 of the connecting nut 26. Is superimposed on the bottom surface 36. Thereby, substantially the entire opening 43 of the resin waste accommodating recess 42 can be covered with the axial end face 44 of the connecting nut 26. As a result, the scattering of resin waste from the resin waste accommodating recess 42 is effectively prevented, and the possibility of poor contact and poor fitting of electrical components due to the scattering of resin waste can be reduced.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the present invention can be applied not only to the plate fixing structure as in the above-described embodiment, but also to, for example, a bus bar, other electrical components, or various members other than electrical components.

  Further, the opening shape of the nut accommodating portion is appropriately set according to the shape of the nut to be accommodated. For example, when a hexagonal nut is used, the hexagonal opening shape or the like is accordingly determined. Can also be adopted.

10: Electrical junction box, 12: Box body (Electric junction box body), 22: Nut housing part, 26: Connection nut, 32: Inner peripheral surface, 34: Press-fitting rib, 36: Bottom surface, 42: Resin waste housing recess , 43: opening, 44: axial end face

Claims (3)

A state where the connecting nut is press-fitted in the axial direction with respect to the nut housing portion formed in the synthetic resin electrical junction box body, and the axial end surface of the connecting nut is overlapped on the bottom surface of the nut housing portion In the electrical junction box assembled in
A plurality of press-fitting ribs extending in the press-fitting direction of the connecting nut on the inner peripheral surface of the nut receiving part and reaching the bottom surface of the nut receiving part are formed in the circumferential direction of the nut receiving part, and the nut receiving part An electrical junction box is formed in which a resin waste containing recess extending around the press-fitting rib is formed on the bottom surface of the electrical connection box.   2. The electrical junction box according to claim 1, wherein a volume of the resin waste accommodating recess is ½ to 1 times a volume of the press-fitting rib.   The electrical junction box according to claim 1 or 2, wherein an opening of the resin waste accommodating recess is covered with the connection nut.

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