JP2010043678A - Locking bolt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a locking bolt capable of fastening and unfastening easily and reliably even when the shape of a female screw of a member to be fastened is a stopper, and exerting an excellent loosening preventing effect by a structure suitable for mass production by reducing the number of components and exerting an excellent loosening preventing effect without machining a thread screw. <P>SOLUTION: The locking bolt comprises a first bolt having one side of the outer peripheral surface with a large diameter male screw and the other side with a small diameter male screw smaller than that of the large diameter male screw, and a second bolt screwed onto the small male diameter screw. The first bolt is so formed that the large diameter male screw and the small diameter male screw differ from each other in pitch, and has the male screw screwed into the female screw of the member to be fastened in upper and lower steps on each outer peripheral surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for preventing a tightening bolt from loosening.

  As a locking bolt, there is generally known a resistance increasing type of a pre-leveling torque type bolt or a locking type bolt in which resistance to the return rotation of the bolt is increased.

  Preveloping torque type bolts increase the resistance by causing interference between the female screw and the male screw from the beginning. Once the locking type bolt starts to loosen, the locking effect is weakened. is there. On the other hand, the locking type bolt has an advantage that a greater resistance can be obtained than the pre-leveling torque type bolt.

  As an example of a pre-torque torque type bolt, a locking bolt 30 as shown in FIG. 6 is known. In this locking bolt 30, a slit portion 32 is formed in the thread of the male screw portion 31.

  As an example of a locking bolt, a locking bolt 40 as shown in FIG. 7 is known. The locking bolt 40 includes a first bolt 41 and a second bolt 42 that have fitting portions opposite to each other and are screwed in two steps on the female screw portion of the tightened member. The joint portion is formed in a conical hole shape whose axial center coincides with the screw hole core. On the other hand, the fitting portion of the first bolt 41 is formed in a truncated cone shape whose shaft center is arranged eccentrically with respect to the screw hole core.

  When the slit 32 of the outer male thread 31 is screwed into the female thread of the member to be tightened, the locking bolt 30 is tightened between the female thread of the member to be tightened by the repulsive force of the slit 32. Will occur. However, since the slits are formed in the screw thread, there is a weak point that the strength of the male screw is reduced, and there is a disadvantage that resistance is generated from the time of screwing and the workability is inferior.

  Further, in the locking bolt 40 shown in FIG. 7, when the first bolt 41 is screwed into the second bolt 42, the amount of misalignment between the cores increases, and the bolt is screwed into a direction perpendicular to the bolt axis. A locking force acts on the to obtain a locking effect. However, in the locking bolt 40, the first bolt 41 and the second bolt 42 are separated from each other, and it is necessary to divide into two times when tightening or removing work. There is.

  In general, many connected locking nuts are known, but there are few connected locking bolts. The reason for this is that the gripping parts of the connected locking nuts are both outside the tightened member, whereas the connected locking bolt that is a locking bolt stops the female threaded part of the tightened member. In this case, one bolt is completely hidden by the tightened member. Therefore, it was very difficult to tighten and remove.

  The present invention has been made in view of the above problems, and even if the female thread portion of the member to be tightened is stopped, it can be easily tightened and removed, and the thread shape is not processed. It is a technical object to provide a locking bolt capable of obtaining an excellent locking effect.

  As means for solving the above problems, the invention of claim 1 is characterized in that a large-diameter male screw portion is formed on one side of the outer peripheral surface and a small-diameter male screw portion having a smaller diameter than the large-diameter male screw portion is formed on the other side. The first bolt is formed from a second bolt that is screwed into the small-diameter male screw portion, and the first bolt is formed so that the pitches of the large-diameter male screw portion and the small-diameter male screw portion are different from each other. It was set as the locking bolt which has a male thread part screwed in two steps of the female thread part of a member to be fastened on each outer peripheral surface.

  In the invention of claim 2, in the invention of claim 1, the first bolt can be formed such that the pitch of the small-diameter male screw portion is smaller than the pitch of the large-diameter male screw portion.

  In the invention of claim 3, in the invention of claim 1 or claim 2, the spiral direction of the small-diameter male screw portion in the first bolt is opposite to the spiral direction of the large-diameter male screw portion in the first bolt. I can do it.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the first bolt and the second bolt may have a grip portion on the outer peripheral surface or the inner peripheral surface.

  According to the locking bolt according to the present invention, even if the female thread portion of the member to be tightened is stopped, it can be easily tightened and removed, and excellent looseness without processing the thread shape. A stopping effect can be obtained.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side sectional view of a locking bolt 10 according to an embodiment of the present invention.

  The locking bolt 10 includes a first bolt 1 and a second bolt 2.

  As for the 1st volt | bolt 1, the holding part is formed in the outer peripheral surface by the predetermined | prescribed two surface width. On the outer peripheral surface of the first bolt 1, a large-diameter male screw portion 1a is formed on one side, and a small-diameter male screw portion 1b having a smaller diameter than the large-diameter male screw portion 1a is formed on the other side. In the large-diameter male screw portion 1a and the small-diameter male screw portion 1b, the spiral direction of the screw is opposite, and in the present embodiment, the small-diameter male screw portion 1b is a left screw. Further, the pitch of the small-diameter male screw portion 1b is different from the pitch of the large-diameter male screw portion 1a, and in this embodiment, the pitch of the small-diameter male screw portion 1b is formed to be smaller.

  The second bolt 2 is formed with a male screw portion 2a having the same diameter and pitch as the large-diameter male screw portion 1a of the first bolt 1 on the outer peripheral surface. These large-diameter male screw portion 1a and male screw portion 2a are shown in FIG. As shown in FIG. 4, the female screw 4a of the member 4 to be tightened is screwed. On the inner peripheral surface of the second bolt 2, a female screw portion 2b that is screwed into the small-diameter male screw portion 1b is formed at the same pitch as the small-diameter male screw portion 1b of the first bolt 1. Further, in FIG. 1, the grip portion is not formed on the second bolt 2, but a grip portion having a two-sided width may be formed on one of the inner peripheral surfaces of the second bolt 2.

  The first bolt 1 and the second bolt 2 described above are assembled as follows.

  As shown in FIG. 1, the first bolt 1 and the second bolt 2 are integrated to prevent loosening by screwing the small-diameter female screw portion 1 b of the first bolt 1 until the female screw portion 2 b of the second bolt 2 is tightly tightened. The fixture 10 is assembled. As described above, the locking bolt 10 of the present embodiment can be handled as a single part in which the first bolt 1 and the second bolt 2 are integrated, so that the tightening operation and the management of the parts can be easily performed. I can do it.

  In addition, when the locking bolt 10 is assembled and integrated in this manner, the phase of the large-diameter female thread portion 1a of the first bolt 1 and the male thread portion 2a of the second bolt 2 is completely in order to be screwed into the female thread without resistance. Matching is a necessary condition, but if the large-diameter male screw portion 1a and the male screw portion 2a are simultaneously processed while being integrated as shown in FIG.

  Next, a method for performing a tightening operation using the locking bolt 10 configured as described above will be described.

  First, as shown in FIG. 2, the locking bolt 10 having the configuration shown in FIG. 1 is screwed into the female screw portion 4a of the member 4 to be tightened from the second bolt 2 side, and the gripping portion of the first bolt 1 is hand-held, spanner or the like. Then screw it in while turning it to the right. As a result, the locking bolt 10 is screwed into the female threaded portion 4 a of the member to be tightened 4 and is screwed in until the first bolt 1 contacts the spring washer 3.

  Further, when the gripping portion of the first bolt 1 is turned to the right, the first bolt 1 receives an upward force from the repulsive force of the spring washer 3 as shown in FIG. A similar force is transmitted to the male screw portion 2a of the second bolt, so that a slip occurs between the small-diameter male screw portion 1b of the first bolt 1 and the female screw portion 2b of the second bolt 2 that has been kept balanced until then. come. In the first bolt 1, the small-diameter male screw portion 1 b is a left-hand screw. Therefore, when the first bolt 1 is turned to the right, the first bolt 1 moves upward relative to the second bolt 2. As shown in FIG. As described above, since the pitch of the small-diameter male screw portion 1b and the female screw portion 2b is smaller than that of the large-diameter male screw portion 1a and the male screw portion 2a, the male screw portion 2a of the second bolt moves the female screw portion 4a of the member 4 to be tightened downward. The threaded portion of the female threaded portion 4a of the tightened member 4 receives a pressing force in the direction of arrow B from the second bolt 2, and receives a pressing force in the direction of arrow A from the first bolt 1. A force in the tensile direction acts on the female screw portion 4a. Thus, a sufficient locking force acts between the locking bolt 10 and the female thread portion 4a of the member 4 to be tightened, and an excellent locking effect can be obtained.

  On the other hand, the removal method will be described. In FIG. 3, contrary to when the first bolt 1 is tightened, when the screw is turned counterclockwise and loosened, the gap E described above is gradually reduced to zero as in assembly. As a result, the locking force is lost, and when the gripping portion of the first bolt 1 is turned counterclockwise, the second bolt 2 also follows smoothly, and the locking bolt 10 can be easily removed from the tightened member 4. Can be released.

  As described above, the locking bolt 10 of the present invention can be tightened and removed by the same working method as a conventional bolt.

  Another embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a side sectional view of the locking bolt 20 according to one embodiment of the present invention. The locking bolt 20 is one in which the locking bolt 10 is turned upside down and the gripping portion is formed on the inner peripheral surface of the end surface of the second bolt 22. However, the small-diameter male screw portion 21b remains a left-hand screw. As shown in FIG. 5, a non-rotating member 25 is incorporated in the inner peripheral surface of the tightened member 24, and the non-rotating straight portion 25a is provided on the outer periphery of the non-rotating member 25 so as not to rotate. Is formed. When the locking bolt 20 is screwed into the female thread portion 24a of the tightened member 24, the first bolt 21 hits the straight portion 25a and a gap F is generated. As in the case of FIG. 3, tensile forces in the opposing arrow C direction and arrow D direction are generated in the female thread portion 24 a of the tightened member 24. In this way, a sufficient locking force acts between the locking bolt 20 and the female threaded portion 24a of the tightened member 24, an excellent locking effect can be obtained, and the locked member 25 can be reliably prevented from loosening. .

  As mentioned above, although two examples were described about embodiment of the present invention, the concrete mode of the present invention is not limited to the above-mentioned embodiment. For example, in this embodiment, the spiral direction of the small-diameter male screw portion 1b is opposite to the spiral direction of the large-diameter male screw portion 1a. However, these directions can be the same. It is also possible to make the small diameter male screw portion 1b larger in pitch than the large diameter male screw portion 1a to form a double thread.

It is side surface sectional drawing of the locking bolt which concerns on one Embodiment of this invention. It is side surface sectional drawing which shows the state in the middle of fastening of the locking bolt shown in FIG. It is side surface sectional drawing which shows the state after the clamping | tightening of the locking bolt shown in FIG. It is side surface sectional drawing of the locking bolt which concerns on one Embodiment of this invention. It is side surface sectional drawing which shows the state after the fastening of the locking bolt shown in FIG. It is side surface sectional drawing of the conventional preveling torque type locking bolt. It is side surface sectional drawing of the conventional locking type locking bolt

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st bolt 1a Large diameter male thread part 1b Small diameter male thread part 1c Holding part 2 Second bolt 2a Male thread part 2b Female thread part 3 Spring washer 4 Tightened member 4a Female thread part 10 Loosening bolt 20 Loosening bolt 24 Tightened member 24a Female thread Portion 25 Protected member 25a Straight portion 30 Locking bolt 40 Locking bolt

Claims (4)

  A first bolt having a large-diameter male screw portion formed on one side of the outer peripheral surface and a small-diameter male screw portion having a smaller diameter than the large-diameter male screw portion on the other side, and a second screwed into the small-diameter male screw portion The first bolt is formed so that the pitches of the large-diameter male screw portion and the small-diameter male screw portion are different from each other, and are screwed into the female screw portion of the member to be tightened in the upper and lower stages on each outer peripheral surface. A locking bolt having a male screw portion.   2. The locking bolt according to claim 1, wherein the first bolt is formed such that a pitch of the small-diameter male screw portion is smaller than a pitch of the large-diameter male screw portion.   The locking bolt according to claim 1 or 2, wherein a spiral direction of the small-diameter male screw portion in the first bolt is opposite to a spiral direction of the large-diameter male screw portion in the first bolt.   The said 1st volt | bolt and a 2nd volt | bolt are locking bolts in any one of Claim 1 to 3 which has a holding part in an outer peripheral surface or an inner peripheral surface.

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