JPWO2014041598A1 - Bolt and structure - Google Patents

Abstract

The bolt (10) is used to fix the member (20) to the member (30), and includes a screw portion (13) and a cylindrical portion (14). The screw (13) of the bolt (10) has a screw (13a) formed on the outer peripheral surface. When the threaded portion (13) is screwed into the threaded hole (31) of the member (30), the male thread (13a) is formed on the inner peripheral surface of the threaded hole (31) and thus engages with the screw. The cylindrical portion (14) of the bolt (10) is inserted into a counterbore hole (32) formed in the opening of the screw hole (31) as the screw portion (13) is screwed into the screw hole (31). It is formed in a fitting shape.

Description

  The present invention relates to a bolt and a structure.

  The bolt is used, for example, to fix another member (second member) to a specific member (first member). When the second member is fixed to the first member with a bolt, for example, the bolt is inserted into the through holes of the first member and the second member, and the nut is screwed into the threaded portion of the bolt. The first member and the second member are fastened to each other (for example, see Patent Document 1 below). Alternatively, the second member is fixed to the first member without using a nut by screwing into a screw hole formed in the first member.

JP 2001-56010 A

  When the second member is fixed to the first member without using a nut with a bolt, depending on the thickness of the first member and the second member and the axial length of the screw thread portion of the bolt, In some cases, the first member and the second member may be disposed at a boundary portion. In this state, for example, when vibration occurs in one of the first member and the second member, a shearing stress is applied to the screw portion of the bolt. Since the thread portion is more likely to concentrate stress than the portion where no screw is formed, this may cause breakage such as cracks.

  The present invention has been made under the above circumstances, and provides a bolt and a structure that are less likely to be damaged due to vibration of a member to which the bolt is fixed.

  In order to achieve the above object, a bolt according to the present invention includes a threaded portion and a fitting portion. The screw portion has a screw formed on the outer peripheral surface. When the threaded portion is screwed into the threaded hole of the first member, the male thread is formed on the inner peripheral surface of the threaded hole and engages with the screw. The fitting portion is formed in a shape that fits into a counterbore hole formed in the opening of the screw hole as the screw portion is screwed into the screw hole.

According to the present invention, the fitting portion of the bolt is fitted into the counterbore portion of the screw hole. For this reason, when vibration occurs in one of the two members fixed by the bolt, a shearing stress is applied to the fitting portion. Thereby, it becomes difficult to produce damage.
Moreover, the structure provided with the bolt according to the present invention is resistant to vibration generated in one of the two members fixed by the bolt. As a result, the lifetime of the structure can be improved.

It is sectional drawing which shows the structure which concerns on Embodiment 1 of this invention. It is an exploded sectional view of the structure concerning Embodiment 1 of the present invention. It is sectional drawing (the 1) for demonstrating the attachment of the volt | bolt which concerns on Embodiment 1 of this invention. FIG. 4 is a partially enlarged cross-sectional view (part 1) of FIG. 3 for explaining the operation of the taper portion of the bolt according to Embodiment 1 of the present invention. FIG. 4 is a partially enlarged cross-sectional view (part 2) of FIG. 3 for explaining the operation of the tapered portion of the bolt according to the first embodiment of the present invention. FIG. 6 is a partial enlarged cross-sectional view (part 3) of FIG. 3 for explaining the operation of the taper portion of the bolt according to the first embodiment of the present invention. It is sectional drawing for demonstrating the effect | action of the volt | bolt which concerns on Embodiment 1 of this invention. It is sectional drawing for demonstrating the effect | action of the volt | bolt which concerns on a comparative example. It is sectional drawing of a structure provided with the bolt of a general shape. It is an exploded sectional view of a structure provided with a bolt of a general shape. It is sectional drawing (the 2) for demonstrating the attachment of the volt | bolt which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure which concerns on Embodiment 2 of this invention. It is the elements on larger scale of FIG. It is sectional drawing which shows the structure which concerns on a modification.

Embodiment 1 FIG.
Hereinafter, structure 100 provided with bolt 10 according to Embodiment 1 of the present invention will be described with reference to FIGS. In order to facilitate understanding, XYZ coordinates are set and referred to as appropriate. The axial direction of the bolt 10 corresponds to the Y-axis direction.

  As illustrated in FIG. 1, the structure 100 is, for example, a part of a hanging drive type railway vehicle, and includes a bolt 10 and members 20 and 30 to which the bolt 10 is to be fixed. In the first embodiment, the members 20 and 30 are fixed by the bolt 10 without using a nut or the like.

  The bolt 10 is comprised from the hexagon bolt, as shown in FIG. The bolt 10 is made of carbon steel, for example, and is formed by plastic processing such as forging. The bolt 10 has a head portion 11 formed in a hexagonal column shape and a shaft portion 12 extending from the head portion 11 to the + Y side.

  The head 11 is a portion exposed to the surface of the member 20 when the bolt 10 is attached to the member 20 and the member 30. A device for rotating the bolt 10 is fitted into the head 11 when the bolt 10 is fixed.

  The shaft portion 12 is a portion that is inserted into the through hole 21 of the member 20 or the screw hole 31 of the member 30, and is formed between the screw portion 13, the cylindrical portion 14, and the screw portion 13 and the cylindrical portion 14. And a tapered portion 15.

  The screw portion 13 is formed at the tip (+ Y side end) of the bolt 10. A male screw 13 a is formed on the outer peripheral surface of the screw portion 13. The nominal diameter D1 of the screw part 13 is, for example, 30 mm (M30).

  Unlike the outer peripheral surface of the screw portion 13, the outer peripheral surface of the cylindrical portion 14 is formed as a smooth surface on which the male screw 13a is not formed. The cylindrical portion 14 functions as a fitting portion that fits into a counterbore portion 32 formed in a screw hole 31 of the member 30 described later. The cylindrical portion 14 has an outer diameter D2 that is larger than a nominal diameter D1 of the screw portion 13. The outer diameter D2 of the cylindrical portion 14 is, for example, 31 mm.

The outer peripheral surface of the taper part 15 is comprised as a taper surface which inclines with respect to the Y-axis direction. The inclination angle θ1 of the taper portion 15 is, for example, in the range of 1.5 ° to 4 °, preferably
It is in the range of 2 ° to 3 °.

  The member 20 is, for example, a tip portion of an arm extending from the motor casing of the motor unit. The + Y side surface and the −Y side surface of the member 20 are formed in a plane parallel to the XZ plane. A through hole 21 is formed in the member 20 so as to penetrate in the Y-axis direction. The through hole 21 is configured as a circular hole having a circular cross section. The through hole 21 has an inner diameter D3 larger than the outer diameter D2 of the cylindrical portion 14 of the bolt 10. The through hole 21 has a length L3 in the Y-axis direction that is smaller than a length L1 obtained by subtracting the thickness of the washer from the length of the cylindrical portion 14 of the bolt 10.

  The member 30 is, for example, a gear case in which a plurality of gears that transmit the rotation of the output shaft of the motor unit are accommodated. The surface on the −Y side of the member 30 is formed in a plane parallel to the XZ plane. A screw hole 31 is formed in the surface on the −Y side of the member 30 (the surface of the gear case).

  The screw hole 31 is a hole formed in a non-penetrating state. A female screw 31 a is formed on a part of the inner peripheral surface of the screw hole 31. The female screw 31a is formed in a shape corresponding to the male screw 13a formed on the outer peripheral surface of the screw portion 13 of the bolt 10. A counterbore 32 is formed in the opening of the screw hole 31.

  The counterbore part 32 is a circular hole in which the female screw 31a or the like is not formed. The counterbore portion 32 has an inner diameter D4 that is equal to the outer diameter D2 of the cylindrical portion 14 of the bolt 10. The cylindrical portion 14 of the shaft portion 12 of the bolt 10 is fitted into the counterbore portion 32. Further, a chamfered curved surface portion 32 a is formed at the opening edge portion of the counterbore hole portion 32 so as to be rounded. The radius of curvature of the curved surface portion 32a is, for example, in the range of 20 mm to 30 mm when the nominal diameter D1 of the screw portion 13 of the bolt 10 is M30 as in the first embodiment.

  The member 20 is fixed to the member 30 configured as described above via the bolt 10. When the member 20 is fixed to the member 30, the operator first sets the member 20 so that the central axis A 2 of the through hole 21 of the member 20 and the central axis A 3 of the screw hole 31 of the member 30 are substantially coaxial. 20 is arranged on the member 30. In this state, the bolt 10 is inserted into the through hole 21 of the member 20. The bolt 10 is inserted into the through hole 21 with the washer 40 attached in advance. When the bolt 10 is inserted into the through hole 21 by an operator, the screw portion 13 at the tip (+ Y side end) of the bolt 10 passes through the through hole 21 and enters the screw hole 31 of the member 30. Moving.

  Next, as shown in FIG. 3, the operator fits the device 50 for screwing the bolt 10 into the head 11 of the bolt 10, and screws the bolt 10 with the device 50. Thereby, the screw portion 13 of the bolt 10 is screwed into the screw hole 31. Furthermore, when the screw portion 13 is screwed into the screw hole 31, the cylindrical portion 14 of the bolt 10 is fitted into the counterbore hole portion 32 as shown in FIG. Then, the head portion 11 of the bolt 10 presses the surface of the member 20 through the washer 40. As described above, the member 20 is fixed to the member 30.

  Further, when the cylindrical portion 14 is fitted into the counterbore hole portion 32, due to the tolerance of the screw hole 31 of the bolt 10 and the member 30, the central axis of the bolt (the central axis A1 shown in FIG. 2) and the screw hole There may be a deviation from the central axis 31 (the central axis A3 shown in FIG. 2). In this case, as shown in FIG. 4A, the tapered portion 15 of the bolt 10 makes point contact with the curved surface portion 32 a of the counterbore hole portion 32 at the contact point C. As shown in FIG. 4B, the tapered portion 15 of the bolt 10 is guided along the curved surface of the curved surface portion 32a while the tapered portion 15 makes point contact with the curved surface portion 32a. Then, as shown in FIG. 4C, the cylindrical portion 14 is fitted into the counterbore hole portion 32.

  As described above, in the first embodiment, the cylindrical portion 14 of the bolt 10 is fitted into the counterbore portion 32 of the member 30. Therefore, for example, as shown in FIG. 5, when vibration in the Z-axis direction as indicated by an arrow G occurs in the member 30, the cylindrical portion 14 disposed on the boundary surface B between the member 20 and the member 30 Shear stress is applied. Since the cylindrical portion 14 is less likely to cause stress concentration than a screw portion having the same diameter with a screw formed on the outer peripheral surface, damage such as a crack is less likely to occur.

  On the other hand, for example, as shown in FIG. 6, when the screw portion 13 is a structure 200 arranged on the boundary surface B between the member 20 and the member 230, the vibration indicated by the arrow G is generated in the member 230. Then, a shear stress is applied to the screw portion 13 disposed on the boundary surface B between the member 20 and the member 230. Since the notch coefficient of the threaded portion 13 is relatively small, stress concentration tends to occur.

  However, in the first embodiment, as shown in FIG. 5, since shear stress is applied to the cylindrical portion 14 instead of the screw portion 13, stress concentration is less likely to occur, and vibration in the Z-axis direction as indicated by the arrow G Damage such as cracks due to the occurrence of cracks is less likely to occur. Further, fatigue failure due to repeated stress is less likely to occur, and the life of the bolt 10 can be improved.

  Moreover, in this Embodiment 1, the taper part 15 of the volt | bolt 10 contacts the curved surface part 32a of the counterbore hole part 32, and the taper part 15 of the volt | bolt 10 is guided along the circular arc of the curved surface part 32a. Is done. Thereby, the insertion property to the screw hole 31 of the volt | bolt 10 can be improved.

  On the other hand, for example, when the tapered portion 15 and the curved surface portion 32 a are not formed, the end surface of the cylindrical portion 14 is caught in the opening of the counterbore hole portion 32, and a large force is applied to the screw 10. It may be necessary. However, in the first embodiment, the taper portion 15 is guided along the curved surface of the curved surface portion 32a, so that the bolt 10 is screwed into the screw hole 31 without requiring a large force for screwing. be able to. As a result, the insertability of the bolt 10 into the screw hole 31 can be improved.

  The bolt 10 according to the first embodiment can be applied in place of a conventional bolt having a general shape during the maintenance of the structure. For example, in the case of a structure 300 to which a conventional bolt 10A having a general shape as shown in FIG. 7A is attached, as shown in FIG. The counterbore part 332 is often not formed. Therefore, as shown in FIG. 7C, the inner peripheral portion R near the opening of the screw hole 331 is removed by machining to form a counterbore portion 332. Then, after the counterbore hole 332 is formed, the bolt 10 according to the first embodiment is attached. Accordingly, the structure 300 includes the bolt 10 according to the first embodiment instead of the conventional bolt 10A, and thus becomes a structure that is resistant to vibration of the member 20 or the member 330. As a result, the lifetime of the structure 300 can be improved.

  Although the first embodiment has been described above, the present invention is not limited to the first embodiment.

  For example, in this Embodiment 1, although the nominal diameter D1 of the thread part 13 of the volt | bolt 10 is M30, not only this but bolts other than M30 may be sufficient.

  Further, in the first embodiment, the inclination angle θ1 of the taper portion 15 of the bolt 10 is in the range of 1.5 ° to 4 °, but is not limited to this, and other than the range of 1.5 ° to 4 °. May be the angle. However, if the inclination angle θ1 is smaller than 1.5 °, the length L4 of the taper portion 15 in the Y-axis direction becomes longer as shown in FIG. There is a possibility that the length L2 of the screw portion 13 becomes too short. When the inclination angle θ1 is larger than 4 °, the tapered portion 15 is less likely to contact the curved surface portion 32a of the counterbore hole portion 32. For this reason, it is preferable that inclination | tilt angle (theta) 1 exists in the range of 1.5 degrees-4 degrees. More preferably, the inclination angle θ1 is in the range of 2 ° to 3 °.

  In the first embodiment, the curvature radius of the curved surface portion 32a of the counterbore hole portion 32 is in the range of 20 mm to 30 mm, but is not limited thereto, and may be a curvature radius other than 20 mm to 30 mm. . However, if the radius of curvature is too small or too large, the tapered portion 15 of the bolt 10 is difficult to contact the curved surface portion 32a of the counterbore hole portion 32. For this reason, it is preferable that the curvature radius of the curved-surface part 32a exists in the range of 20 mm-30 mm. The radius of curvature needs to be a size corresponding to the nominal diameter D1 of the threaded portion 13 of the bolt 10.

Embodiment 2. FIG.
In the structure 100 according to the first embodiment, the bolt 10 is formed with the tapered portion 15, and the counterbore portion 32 of the member 30 is formed with the curved surface portion 32 a. On the other hand, in the structure 100A according to the second embodiment, as shown in FIGS. 8 and 9, the curved surface portion 16 is formed on the bolt 10A, and the counterbore portion 32 of the member 30 is A tapered portion 32b is formed.

  The curved surface portion 16 of the bolt 10A is formed between the screw portion 13 and the cylindrical portion 14 of the bolt 10A. The curved surface portion 16 is constituted by a curved surface having a predetermined curvature radius, for example.

  A tapered portion 32 b is formed at the opening edge portion of the counterbore hole portion 32. The outer peripheral surface of the taper part 32b is comprised as a taper surface which inclines with respect to the Y-axis direction. The inclination angle of the taper portion 15 is, for example, in the range of 1.5 ° to 4 °. More preferably, it exists in the range of 2 degrees-3 degrees.

  In the second embodiment, when the cylindrical portion 14 is fitted into the counterbore hole portion 32, due to a tolerance or the like, there is a deviation between the central axis of the bolt 10A and the central axis of the screw hole 31. The curved surface portion 16 of the bolt 10 </ b> A makes point contact with the tapered portion 32 b of the counterbore hole portion 32. The curved surface portion 16 of the bolt 10 is guided along the inclined surface of the tapered portion 32b while the curved surface portion 16 makes point contact with the tapered portion 32b. Then, the cylindrical portion 14 is fitted into the counterbore hole portion 32.

  As described above, also in the second embodiment, the curved surface portion 16 of the bolt 10A is in point contact with the tapered portion 32b of the counterbore hole portion 32, so that the curved surface portion 16 of the bolt 10 is Guided along the slope. Thereby, the insertability of the bolt 10A into the screw hole 31 can be improved.

  Although the first and second embodiments have been described above, the present invention is not limited to the first and second embodiments. For example, in the second embodiment, the radius of curvature of the curved surface portion 16, the inclination angle of the tapered portion 32b, and the like can be changed as appropriate.

  In the first and second embodiments, the fitting portion that fits into the counterbore portion 32 is a part of the cylindrical portion 14. However, the present invention is not limited to this, and as shown in FIG. 10, the fitting portion 17 may be formed in another portion having an outer diameter slightly larger than the cylindrical portion 18.

  Moreover, in the said Embodiment 1, the taper part 15 is formed in the volt | bolt 10, and the curved surface part 32a is formed in the counterbore hole part 32 so that the taper part 15 may be point-contacted. In the second embodiment, the curved surface portion 16 is formed on the bolt 10 </ b> A, and the tapered portion 32 b is formed on the spot facing hole portion 32 so as to make point contact with the curved surface portion 16. However, the present invention is not limited to this, as long as a part of the bolt 10 or 10A is in point contact with a part of the counterbore hole 32 and improves the insertability of the bolt 10 or 10A. Also good. However, when the tapered portions 15 and 32b are formed in both the bolt 10 and the counterbore hole portion 32, the contact is not a point contact but a line contact, and the frictional resistance when the bolt 10 is inserted increases. For this reason, it is preferable that the tapered portions 15 and 32b and the curved surface portions 16 and 32a have a point-contact shape.

  In the first and second embodiments, the member 20 is a tip portion of an arm extending from the motor casing of the motor unit, and the members 30, 30A, 30B are a plurality of members that transmit the rotation of the output shaft of the motor unit. This is a gear case that houses gears. The structures 100, 100A, and 100B are part of a suspension drive type railway vehicle. However, the present invention is not limited to this, and may be a part of an industrial machine tool or equipment. In particular, the present invention is suitable for use in vehicles, machine tools, equipment and the like that generate vibration during operation.

  Various embodiments and modifications can be made to the present invention without departing from the broad spirit and scope of the present invention. The above-described embodiments are for explaining the present invention, and do not limit the scope of the present invention.

  The bolt and the bolt structure of the present invention are suitable for fixing a motor unit of a railway vehicle to a gear box.

10, 10A, 10B, 310 Bolt 11 Head 12 Shaft portion 13 Screw portion 13a Male screw 14 Cylindrical portion (fitting portion)
15 Tapered part 16 Curved surface part 17 Fitting part 18 Cylindrical part 20 Member (second member)
21 Through-hole 30, 230, 330 Member (first member)
31, 331 Screw hole 31a Female thread 32, 332 Counterbore part 32a Curved part 32b Tapered part 40 Washer 50 Equipment 100, 100A, 100B, 200, 300 Structure D1 Nominal diameter D2 Outer diameter D3, D4 Inner diameter L1-L4 Long A1 to A3 Central axis B Boundary surface C Contact point G Arrow R Inner circumferential part θ1 Inclination angle

In order to achieve the above-described object, a bolt according to the present invention includes a screw portion, a fitting portion, and a guide portion . The screw portion has a screw formed on the outer peripheral surface. When the threaded portion is screwed into the threaded hole of the first member, the male thread is formed on the inner peripheral surface of the threaded hole and engages with the screw. The fitting portion is formed in a shape that fits into a counterbore hole formed in the opening of the screw hole as the screw portion is screwed into the screw hole. The guide portion is formed between the fitting portion and the screw portion, and is formed so as to make point contact with a guided surface formed at the opening edge portion of the counterbore hole portion. The guide portion is guided along the guided surface while making point contact with the guided surface, so that the fitting portion is fitted into the counterbore hole portion.

In order to achieve the above object, a bolt according to the present invention includes a threaded portion, a fitting portion, and a tapered portion. The screw portion has a screw formed on the outer peripheral surface. When the threaded portion is screwed into the threaded hole of the first member, the male thread is formed on the inner peripheral surface of the threaded hole and engages with the screw. The fitting portion is formed in a shape that fits into a counterbore hole formed in the opening of the screw hole as the screw portion is screwed into the screw hole. The tapered portion is formed between the fitting portion and the threaded portion, so as to come in contact to the curved portion formed in the opening edge portion of the counterbore holes, inclined relative to the axial direction. The tapered portion, while touch contact with the curved surface portion, by being guided along the curved surface portion, the fitting portion is fitted into the countersunk hole.

Claims (9)

A screw portion screwed into the screw hole of the first member and formed on the inner peripheral surface of the screw hole and thus engaged with the screw;
A fitting portion formed in a shape that fits into a counterbore hole portion formed in the opening of the screw hole as the screw portion is screwed into the screw hole.
Bolt equipped with.   The bolt according to claim 1, further comprising a tapered portion that is formed between the fitting portion and the screw portion and is inclined with respect to the axial direction.   The bolt according to claim 1, further comprising a curved surface portion formed between the fitting portion and the screw portion and having an outer peripheral surface formed into a curved surface.   The said fitting part is a volt | bolt as described in any one of Claims 1 thru | or 3 comprised from at least one part of a bolt cylindrical part. A first member provided with a screw hole in which a female screw is formed on the inner peripheral surface and a counterbore hole is formed in the opening;
The bolt according to any one of claims 1 to 4,
A structure having   The structure according to claim 5, wherein a tapered portion that is inclined with respect to the axial direction is formed at an opening edge portion of the counterbore portion of the first member.   The structure according to claim 5, wherein a chamfered curved surface portion is formed at an opening edge portion of the counterbore hole portion of the first member.   The through-hole into which the said volt | bolt is inserted is formed, and it has a 2nd member fixed to the said 1st member by inserting the said volt | bolt in the said through-hole. Structure. The second member is composed of a tip portion of an arm extending from a motor casing of a motor unit of a railway vehicle,
The structure according to claim 8, wherein the first member includes a gear case in which a plurality of gears that transmit rotation of the output shaft of the motor unit are housed.

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