JP4657268B2 - tightening structure - Google Patents

Description

  The present invention relates to a fastening structure.

  Conventionally, in order to prevent a tightening mistake that the bolt is screwed in a state of being significantly inclined with respect to the nut, the shaft shape formed on the end side of the male screw of the bolt is slightly smaller than the diameter of the male screw. A fastening structure is known in which a guide pin portion is provided to guide a bolt at the start of tightening to a correct angle (see, for example, Patent Document 1).

  In the case of the above-described fastening structure, although a fastening error can be reduced to some extent, as shown in FIG. 6, for example, when a fastening operation is performed on an object installed in an inclined state, the nut at the start of fastening The inclination of the bolt 200 with respect to 100 becomes relatively large, and even if the guide pin 300 is provided, a tightening error may occur. When the tightening portion is a terminal such as an electric wiring, there is a possibility that the bolt 200 may be loosened due to a tightening error later, resulting in poor contact. Therefore, a more reliable fastening structure has been desired.

  For example, in order to prevent the above-described tightening error, the guide pin 300 of the bolt 200 is lengthened and the thickness of the nut 100 is increased to further reduce the inclination of the bolt 200 at the start of tightening. However, when configured in this way, a dedicated nut is required, which increases the cost. Thus, as a configuration using a general-purpose nut, for example, it is conceivable to provide a cylindrical portion in the bolt tightening direction along the axis of the female screw portion of the nut to guide the guide pin of the bolt.

Specifically, as shown in the reference example of FIG. 7, a cylindrical guide pin 301 extending in the axial direction from the end of the screw portion 202 of the bolt 201 is provided, while the nut 101 is immersed in the casing 400. A concave portion 401 is formed, and a cylindrical portion 402 slightly shorter than the guide pin 301 is formed inside the concave portion 401, and an inner diameter substantially the same as the above-described guide pin 301 is formed at the outlet of the cylindrical portion 402. By providing the provided guide hole 403, the guide pin 301 is guided to the guide hole 403 at the start of tightening of the bolt 201, and the inclination angle of the bolt 201 with respect to the nut 401 can be reduced to a range that does not cause a tightening error. While using the general-purpose nut 101, it is possible to reduce the tightening error as compared with the conventional fastening structure described above.
JP 2001-304221 A

By the way, in the fastening structure shown in the above-mentioned reference example, although the general-purpose nut 101 can be used, the position of the screw hole 102 of the general-purpose nut 101 may be slightly shifted from the center. The center of the 102 and the center of the guide hole 403 are displaced from each other and, as shown in FIG. 7, the male screw of the screw portion 202 of the bolt 201 and the screw of the nut 101 are not caused to cause a direct tightening error. Bolts are screwed in a state of being inclined by the tolerance (backlash) of the female screw of the hole 102 (see FIG. 8).
However, immediately before the completion of tightening of the bolt 201 (see FIG. 9), the lower surface 204 of the head 203 of the bolt 201 tries to come into close contact with the upper surface 103 of the nut 101, and the position of the guide pin 301 is the diameter of the guide hole 403. Since the outer side of the guide pin 301 is displaced outward (indicated by an arrow in FIG. 9), the peripheral surface of the guide pin 301 presses the guide hole 403 from the inner side, places a burden on the guide hole 403 and its surroundings, and the bolt 201 is completely tightened. May be disturbed.

  Therefore, the present invention can be securely fastened by using a general-purpose nut, and can prevent a load from being applied to the guide hole and its surroundings or hindering the completion of bolt tightening. Provide structure.

In order to solve the above-described problems, the invention described in claim 1 is characterized in that a fastening portion (for example, the terminal portion 2 in the embodiment) provided with a nut (for example, the nut 6 in the embodiment) is screwed onto the nut. In a fastening structure in which a fastened portion is fastened and connected by a bolt to be joined (for example, the bolt 3 in the embodiment), the bolt is extended from an end portion of a screw portion (for example, the screw portion 5 in the embodiment) of the bolt. Rutotomoni threaded portion slightly reduced diameter pin (e.g., the guide pin 7 in the embodiment) than the outer diameter of, and a casing with a recess formed for accommodating the nut to the outer wall, the said casing guide tube is formed toward the inside of the recess, the inner circumference of the guide tube is formed by diameter than the screw hole of the nut, the end portion of the guide tube may be guiding the pin Guide holes (e.g., the guide hole 15 in the embodiment) is formed, the guide hole, the than the outer diameter of and the pin diameter smaller than the inner diameter of the guide cylinder is formed larger in diameter, screwed before The bolt is provided at a position separated from the nut by a predetermined distance that can contact the pin of the bolt just before being screwed so as to make the inclination angle of the bolt within a predetermined range and guide the pin . An angle range in which the screw portion of the bolt can be screwed into the screw hole of the nut, and the pin is guided to the pin by the guide hole at a position corresponding to the guide hole when tightening of the bolt is completed. It is characterized by having a constriction part (for example, the constriction part 9 in the embodiment) for releasing the above.

  According to a second aspect of the present invention, in the first aspect of the present invention, a base portion on the screw portion side from the constricted portion of the pin, and a tip portion on the opposite side of the screw portion from the constricted portion of the pin. Are set to be substantially the same as the thickness of the nut.

  The invention described in claim 3 is characterized in that a taper surface for guiding the pin (for example, a taper surface 16 in the embodiment) is provided on the periphery of the guide hole on the nut side.

  According to the first aspect of the present invention, the bolt has the guide hole that is separated from the nut by a predetermined distance, and the bolt is provided with a pin that is guided by the guide hole. Since the inclination angle can be reduced as the distance between the guide holes becomes longer, there is an effect that reliable fastening can be performed while reducing the cost by using a general-purpose nut.

  Also, for example, when the center axis of the screw hole of the nut and the center axis of the guide hole are slightly shifted, the bolt is screwed in with the bolt and the nut being inclined by the margin of tolerance. When completed, the screw thread of the bolt tries to be displaced straight with respect to the screw hole of the nut, but the guide of the pin by the guide hole is released by providing the constricted part, so the pin is not in the guide hole. There is an effect that it is possible to prevent the inner peripheral surface from being pressed to place a burden on the guide hole and its surroundings or to inhibit the completion of bolt tightening.

According to the invention described in claim 2, in addition to the effect described in claim 1, since the total length of the pin is sufficiently longer than the thickness of the nut, the inclination angle of the bolt with respect to the nut at the start of bolt tightening is set to be extremely small. Therefore, there is an effect that a fastening error can be surely prevented.
In addition, since the length of the pin can be set to the minimum necessary length for obtaining the effect of preventing the inclination of the screw portion, the fastening portion can be reduced in size.

  According to the third aspect of the invention, in addition to the effect of the first or second aspect, the tapered surface is formed on the nut side periphery of the guide hole, so that the pin can be smoothly inserted when the bolt is guided to the tightening start position. Since it is inserted into the guide hole, it is possible to improve workability and to reduce the burden on the operator.

Next, embodiments of the present invention will be described with reference to the drawings. In this embodiment, a terminal part that is a fastening part for connecting a power terminal to a fuse box of a vehicle will be described as an example. For the sake of illustration, the power supply terminals are not shown in this embodiment.
The fuse box 1 shown in FIGS. 1 and 2 is, for example, fixed in an inclined state below a vehicle instrument panel. The operator fixes the fuse box 1 at an angle, so when fixing the power terminal to the terminal 2, set the bolt 3 in an oblique direction according to the inclination of the fuse box 1 and tighten it with an impact driver. Fix it.

  The bolt 3 has a screw head 4 such as a hex lobe or a hexagon, and a base end side of a screw portion 5 which is a male screw is connected to the center of the screw head 4. The screw portion 5 is formed to be slightly longer than the female screw of the nut 6, and a guide pin 7 having a predetermined length extends from the end portion side.

  The guide pin 7 is slightly reduced in diameter from the outer diameter of the screw portion 5 and is disposed on the screw portion 5 side. The guide pin 7 has an outer diameter substantially the same as the base portion 8a and is disposed on the opposite side of the screw portion 5. And an end portion 8b, and a constricted portion 9 formed between the base portion 8a and the end portion 8b. The constricted portion 9 has a predetermined width along the axial direction of the guide pin 7 and is stepped and formed with a diameter smaller than that of the base portion 8a and the end portion 8b. The length along the axial direction of each of the base portion 8 a and the end portion 8 b is set to be slightly longer than the length d of the screw hole 10 of the nut 6. That is, the guide pin 7 is formed with a dimension sufficiently longer than twice the length d of the screw hole 10. Here, the shape of the screw head 4 and the screw portion 5 is in accordance with a standard such as the JIS standard.

  On the other hand, the nut 6 is a so-called general-purpose nut, and the outer shape thereof is formed in a substantially square shape when viewed from above, and has a screw hole 10 that is a female screw at the center. The nut 6 is accommodated in the casing 11 of the fuse box 1 in a state in which rotation is restricted by being embedded or fitted. The general-purpose nut is a nut having a shape conforming to a standard such as JIS standard.

  The fuse box 1 is a box that accommodates a fuse (not shown) in a resin casing 11, and a recess 12 that accommodates a nut 6 is formed on the outer wall of the casing 11. The recess 12 is provided with a vertical wall disposed in a substantially square shape corresponding to the outer shape of the nut 6, for example, as viewed from above, and restricts the rotation of the nut 6 accommodated in the recess 12. Further, the bottom wall 13 of the recess 12 is formed to be thicker than the outer wall of the surrounding casing 11.

  A guide cylinder 14 is formed in the casing 11 toward the inside of the recess 12 described above. The inner circumference of the guide cylinder 14 is formed to be slightly larger than the screw hole 10 of the nut 6. At the end of the guide cylinder 14, a guide hole 15 is formed which is smaller in diameter than the inner diameter of the guide cylinder 14 and slightly larger in diameter than the outer diameter of the guide pin 7. A tapered surface 16 that is inclined downward from the outer wall of the guide tube 14 toward the guide hole 15 is formed on the periphery of the guide hole 15 on the nut 6 side. And the center of the above-mentioned recessed part 12, the axis line of the guide cylinder 14, and the center of the guide hole 15 are arrange | positioned on the straight line (it shows with the dashed-dotted line in FIG. 1), respectively.

  As shown in FIG. 5, the above-mentioned constricted portion 9 faces the position corresponding to the guide hole 15 when the bolt 3 is completely tightened to the nut 6, specifically, the inner peripheral surface of the guide hole 15. On the guide pin 7 to be formed, it is formed to be sufficiently wider than the inner peripheral surface of the guide hole 15. The guide hole 15 is disposed at a predetermined distance from the inner surface of the nut 6 via the guide tube 14. More specifically, the guide hole 15 has a predetermined distance obtained by adding the length of the constricted portion 9 and the base portion 8a adjacent to the constricted portion 9 and the protruding portion of the screw portion 5 from below the nut 6. It is spaced apart from the inner surface.

Next, the effect | action of the fastening structure mentioned above is demonstrated, referring FIGS.
As shown in FIG. 2, when there is almost no deviation in the center position of the screw hole 10 of the nut 6, the center axis of the screw hole 10 and the center axis of the guide hole 15 are arranged on a substantially straight line. When the guide pin 7 of the bolt 3 is inserted into the screw hole 10 of the nut 6 and the end of the screw part 5 is arranged at the inlet of the screw hole 10 in order to arrange the bolt 3 at the fastening start position, The end 8 b is guided by the tapered surface 16 and inserted into the guide hole 15. Then, the central axis of the end portion 8b of the guide pin 7 guided by the screw hole 10 is arranged on an extension line of the central axis of the screw hole 10, and as a result, the axis of the screw portion 5 of the bolt 3 and the nut 6 are arranged. It is possible to reduce the inclination angle of the bolt 3 before being screwed with the nut 6 to a range that does not cause a tightening error.

  Next, as shown in FIG. 3, when a slight deviation occurs in the center of the screw hole 10 of the nut 6, an axis line connecting the center of the screw hole 10 and the center of the guide hole 15 ( L1 (indicated by the alternate long and short dash line) does not coincide with the axis line L2 of the screw hole 10 (indicated by the alternate long and short dash line in FIG. 3), but is inclined with respect to the axial line L2 by a predetermined angle θ corresponding to the amount of deviation. The deviation of the screw hole 10 is such that the bolt 3 can be screwed in, for example, a deviation within a tolerance range, or a deviation that can be absorbed by the tolerance (backlash) between the male screw and the female screw.

  First, in order to arrange the bolt 3 at the fastening start position, when the guide pin 7 of the bolt 3 is inserted into the screw hole 10 of the nut 6 and the end of the screw part 5 is arranged at the inlet of the screw hole 10, the guide pin 7 is guided by the tapered surface 16 and inserted into the guide hole 15. When the axis L1 connecting the center of the screw hole 10 and the center of the guide hole 15 is inclined with respect to the axis L2 of the screw hole 10, the axis of the screw portion 5 of the bolt 3 is aligned with the center of the screw hole 10 described above. It arrange | positions on the axis line L1 which tied the center of the guide hole 15, and it will be in the state which the axis line of the screw part 5 of the volt | bolt 3 and the axis line L2 of the screw hole 10 of the nut 6 do not correspond, and inclined.

  When the bolt 3 is tightened with an impact driver or the like in this inclined state, as shown in FIG. 4, the bolt 3 is in a state where the guide portion 8 on the end portion side of the guide pin 7 slightly presses the inner periphery of the guide hole 15. Displaces in the tightening direction. FIG. 5 shows the time point when the fastening is completed. Immediately before the completion of the fastening, the bottom surface of the screw head 4 of the bolt 3 and the outer surface of the nut 6 are swung in a direction (arrow direction in the figure), The axial direction of the screw part 5 which was in an inclined state and the axial line L2 of the screw hole 10 are displaced in a matching direction.

  At this time, the direction indicated by the arrow from the position indicated by the two-dot chain line in FIG. 5, that is, the end side of the guide pin 7 tends to be displaced toward the radially outer side of the guide portion 8. Since the constricted portion 9 has reached the position of the guide hole 15, the inner peripheral portion of the guide hole 15 enters the space formed in the constricted portion 9 due to the displacement of the guide pin 7, and the guide hole 15 becomes the guide pin 7. Is not pressed radially outward.

  Here, the constricted portion 9 is formed with a reduced diameter by an amount corresponding to a displacement assumed when the guide pin 7 is displaced from an inclined state to a straight state. This assumed displacement can be obtained from the upper limit value of the tilt angle at which the bolt 3 can be screwed into the nut 6. The predetermined width of the constricted portion 9 described above is a width obtained by adding a margin to the axial thickness of the guide hole 15. 5 shows a case where the outer peripheral surface of the constricted portion 9 and the inner peripheral surface of the guide hole 15 are separated from each other. However, the constricted portion 9 can be used as long as the guide hole 15 and the casing 11 are not burdened. The outer peripheral surface of the guide hole 15 may be in contact with the inner peripheral surface of the guide hole 15.

  Therefore, according to the above-described embodiment, the casing 11 includes the guide hole 15 that is separated from the nut 6 by a predetermined distance, and the bolt 3 includes the guide pin 7 that is guided to the guide hole 15. Since the angle of the bolt 3 with respect to the nut 6 at the start of tightening of the bolt 3 can be reduced as the separation distance of the guide hole 15 becomes longer, the nut 6 which is a general-purpose nut is used to reduce the cost and perform the reliable fastening. It can be carried out.

  Further, when the central axis of the screw hole 10 of the nut 6 and the central axis of the guide hole 15 are slightly shifted, the bolt 3 is screwed in with the bolt 3 and the nut 6 being inclined by an amount of margin. 3 is completed, the screw portion 5 of the bolt 3 tends to be displaced straight with respect to the screw hole 10 of the nut 6. At this time, the guide at a position facing the inner peripheral surface of the guide hole 15 is used. By providing the constricted portion 9 on the pin 7, the guide pin 7 presses the inner peripheral surface of the guide hole 15 to the extent that the diameter is reduced by the constricted portion 9, so that the guide hole 15 and the surrounding guide cylinder 14 are provided. In addition, it is possible to prevent the casing 11 from being burdened or hindering the completion of the bolt 3 from being tightened.

  Furthermore, the length of the guide pin 7 is set sufficiently long with respect to the nut 6 by setting the length of each of the base 8 a and the end 8 b to be equal to or greater than the length of the screw hole 10 of the nut 6. Therefore, the inclination angle of the bolt 3 with respect to the nut 6 at the start of tightening can be set extremely small, and as a result, a tightening error can be reliably prevented.

  Since the tapered surface 16 is formed on the periphery of the guide hole 15, the guide pin 7 is smoothly inserted into the guide hole 15 when the bolt 3 is guided to the tightening start position, thereby improving workability. Can reduce the burden on the operator.

  Next, another aspect of the above-described embodiment will be described with reference to FIG. In addition, since the other aspect of this embodiment changes the base 8a and the edge part 8b of the guide pin 7 of embodiment mentioned above, the same code | symbol is attached | subjected to the same part as the above-mentioned embodiment. Only the differences will be described.

  As shown in FIG. 10, the bolt 3 is provided with a guide pin 7 extending from the end thereof, and the guide pin 7 is disposed between the base portion 8c and the end portion 8d and between the base portion 8c and the end portion 8d. And a constricted portion 9 to be formed. The lengths of the base 8c and the end 8d are set to be substantially the same as the length d (see FIG. 1) of the screw hole 10 of the nut 6 into which the bolt 3 is screwed. The nut 6 is a general-purpose nut as in the above-described embodiment.

  The base portion 8c is made shorter than the base portion 8b of the above-described embodiment, and the constricted portion 9 is thereby arranged closer to the nut 6 than the constricted portion 9 of the above-described embodiment. And the guide hole 15 is arrange | positioned according to the position of the constriction part 9, and the cylindrical part 14a arrange | positioned inside the nut 6 of the casing 11 is only the part by which the constriction part 9 is arrange | positioned more on the nut 6 side. Shortened.

  According to another aspect of this embodiment, the length dimension of the base portion 8c and the length dimension of the end portion 8d are set to be substantially the same as the length dimension of the screw hole 5 of the nut 6, so that the guide Since the pin 7 can be made the minimum length necessary for obtaining the effect of preventing the inclination of the screw portion 5, and the cylindrical portion 14c can also be shortened, a nut necessary for performing a reliable fastening While the inclination angle of the bolt 3 with respect to 6 is secured, the terminal portion 2 that is the fastening portion can be downsized.

  The present invention is not limited to the above-described embodiment and other aspects, and is not limited to a vehicle fuse box. And although the case where the to-be-fastened part was a power supply terminal was demonstrated, it is not restricted to this.

Moreover, although the said embodiment and the other aspect demonstrated the case where the outer surface of the nut 6 was arrange | positioned flush with the outer surface of the casing 11, the nut 6 was embedded beforehand in the casing 11 and integrated. It may be formed automatically.
Furthermore, although the case where the guide hole 15 is disposed by being separated by a predetermined distance via the cylindrical guide tube 14 has been described, the guide hole 15 is not limited to the guide tube 14.

It is sectional drawing of the fastening structure in embodiment of this invention. It is sectional drawing of the fastening structure in case the center of the screw hole of the nut in embodiment of this invention has not shifted | deviated. It is sectional drawing before the fastening of the fastening structure in case the center of the screw hole of the nut in the embodiment of this invention has shifted | deviated. FIG. 4 is a cross-sectional view corresponding to FIG. 3 during tightening. FIG. 4 is a cross-sectional view corresponding to FIG. 3 after tightening. It is sectional drawing of the conventional fastening structure. It is sectional drawing before the fastening of the fastening structure in a reference example. FIG. 8 is a cross-sectional view corresponding to FIG. 7 during tightening. FIG. 8 is a cross-sectional view corresponding to FIG. 7 after tightening. FIG. 4 is a cross-sectional view corresponding to FIG. 3 before tightening in another aspect of the embodiment of the present invention.

Explanation of symbols

2 Terminal part (fastening part)
3 Bolt 5 Screw part 6 Nut 7 Guide pin (pin)
9 Constricted part 11 Casing 15 Guide hole 16 Tapered surface

Claims (3)

In the fastening structure in which the fastened portion is fastened and connected to the fastening portion provided with the nut by a bolt screwed into the nut,
A pin that is formed to extend from the end of the threaded portion of the bolt and is slightly smaller in diameter than the outer diameter of the threaded portion;
A casing formed with a recess for accommodating the nut on the outer wall ,
A guide tube is formed in the casing toward the inside of the recess,
The inner periphery of the guide tube is formed with a diameter larger than the screw hole of the nut,
A guide hole for guiding the pin is formed at an end of the guide tube ,
The guide hole is
The pin of the bolt that is formed to have a smaller diameter than the inner diameter of the guide cylinder and larger than the outer diameter of the pin, and to be screwed in so that the inclination angle of the bolt before screwing is within a predetermined range. Is provided at a position separated from the nut by a predetermined distance capable of guiding the pin by contacting the pin ,
The predetermined range is an angle range in which the screw portion of the bolt can be screwed into the screw hole of the nut,
The pin is
A fastening structure comprising a constricted portion for releasing the guide of the pin by the guide hole at a position corresponding to the guide hole when the tightening of the bolt is completed.   The base of the pin on the side of the screw part from the constricted part and the tip part of the pin on the side opposite to the screw part are set to be substantially the same as the thickness of the nut. The fastening structure according to claim 1.   The fastening structure according to claim 1 or 2, wherein a taper surface for guiding the pin is provided on a peripheral edge of the guide hole on the nut side.

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