JP2011179560A - Bolt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the occurrence of rubbing on the seat surface of a fastened member, with which the rear-surface side of a bolt head is in contact when the fastened member is fastened, due to rotational sliding for fastening so as to allow application of force in a fastening direction only and to reduce tightening torque required for fastening. <P>SOLUTION: The bolt comprises: a bolt member 3 having a main screw 1 at the lower part and an auxiliary screw 2 at the upper part respectively; and a nut member 4 screwed to the auxiliary screw 2 of the bolt member 3. A spiral pitch of the auxiliary screw 2 is configured to be shorter than that of the main screw 1. The bolt member 3 is configured to have a bolt head 6 on its uppermost part. The bolt head 6 is configured to have a size that allows the nut member 4, to be screwed to the auxiliary screw 2, to smoothly pass therethrough. The nut member 4 is configured as follows. When the main screw 1 of the bolt member 3 is screwed into a female screw 9 of a fastened member 7 on the lower side or the depth side, the rear-surface side of the nut member is in contact with the seat surface of the fastened member 8 on the upper side or the front side. Then, the rotation of the nut member automatically stops. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bolt that is used when two or more members to be fastened are joined, and in particular, when fastened, the sliding with respect to the seating surface (contact surface) of the fastened member that contacts the back side of the bolt head. It is related with the volt | bolt which can perform fastening operation by comparatively low torque, avoiding the scraping by.

  There are many proposals related to bolts, such as those related to locking after loosening with bolts and nuts, etc., but when two bolted members are joined by bolts, There is no proposal for a bolt that can be tightened with a desired low torque without adversely affecting the seating surface (contact surface) of the member to be fastened due to rotational sliding of the bolt.

  Patent Document 1 relates to a bolt and a nut for fixing an article to a base, wherein the bolt includes a lower screw and an upper screw having different pitches, and the base includes a base screw to which the lower screw of the bolt can be screwed. A nut is screwed onto the upper screw of the bolt.

  The bolt and nut are fixed to the base by screwing a lower screw to the base screw, the member to be coupled to the base, and the bolt to the bolt hole. After mounting while penetrating, the nut is screwed onto the bolt and fixed. Further, the member to be coupled can be removed by removing the nut by rotating it in the opposite direction.

  According to the description of Patent Document 1, since the bolt has a different pitch between the upper screw and the lower screw, when removing the bolt, it can be prevented from turning around. It is very doubtful whether a correct result will be obtained. In addition, there is an example in which the direction of the upper screw and lower screw of the bolt is reversed, and there is also an explanation that it is possible to prevent rotation of both, but this is certainly the case, The explanation seems incorrect. In addition, regarding the fact that the upper screw and the lower screw are reversed, as described above, it can be said that the bolt can be prevented from coming off when the nut is loosened, but this is certainly not the case when tightening the nut. There is a risk that the bolt will come off. Therefore, it cannot be said that it is convenient to use in such a manner that tightening and loosening are repeated. Further, regarding the change of the pitch of the upper screw and the lower screw of the bolt, no meaningful usage / function / action / effect is shown.

  Patent Document 2 discloses a first screwed portion formed as a first spiral-shaped mountain having a predetermined diameter, pitch, and number of stripes, and is adjacent to the first screwed portion and is the same as the first screwed portion. A gap is formed between the second threaded portion formed as a second spiral-shaped peak in the same direction having the diameter, pitch, and number of threads, and the first threaded portion and the second threaded portion. A notch groove, and the first screw part and the second screw part have the notch groove so that the phase of the first spiral peak differs from the phase of the second spiral peak. It is a bolt with a locking stopper arranged through.

  When a nut is screwed onto this bolt with a locking screw and the nut is in a screwed state across the first screwed portion and the second screwed portion, the first screwed according to the phase relationship. The frictional resistance force (fastening force) applied from the portion to the nut can be made different from the magnitude of the frictional resistance force applied from the second threaded portion, and a loosening prevention effect can be obtained. However, since the nut is screwed into the bolt that is out of phase from the middle, it seems that the thread and trough of the screw and the nut are biting into each other, and the effect of locking is sufficient. However, it is difficult to loosen the nut to remove it from the bolt, and even if it can be removed, the threads and valleys will be damaged and the nut will be screwed again. It seems impossible. Therefore, it is a bolt that is difficult to use when it may be removed later.

  As described above, there are many proposals for bolts and nuts to prevent loosening of the bolts and nuts after the fastening. There is no proposal regarding a bolt that can be fastened without causing a rusting phenomenon due to rotational sliding with the bolt on the seating surface (contact surface) of the member to be fastened. By the way, only the axial force is required for the connection of the two fastened members with the bolts, and the force in the rotating direction damages the seating surface (contact surface) with the back of the bolt head of the fastened member. There is only a fear of attaching, and there is no advantage even if there is harm.

JP 2007-064258 A JP 2007-155105 A

  The present invention avoids the occurrence of scraping due to rotational sliding for bolt tightening on the seating surface (contact surface) of the member to be fastened, which is in contact with the back side of the bolt head when the bolt is fastened to the member to be fastened. However, it is an object of the present invention to provide a bolt that can apply only the force in the fastening direction, that is, the axial direction of the bolt, and can reduce the tightening torque required for fastening.

  1 of the present invention is provided with a main screw portion at a lower portion, an auxiliary screw portion having a helix having a shorter pitch than the helix above the main screw portion, and a nut screwed into the auxiliary screw portion above the auxiliary screw portion It is the volt | bolt comprised by the bolt member provided with the bolt head of the size which can pass a member, and the nut member screwed together in the auxiliary | assistant screw part of this bolt member.

  According to the second aspect of the present invention, in the bolt of the first aspect of the present invention, the helical pitch of the auxiliary screw portion is set to a dimension of 20 to 90% of the helical pitch of the main screw portion.

  According to the bolt of 1 of the present invention, the fastened member can be fastened with low torque while eliminating the friction caused by the rotational sliding of the back surface side of the nut member with respect to the seating surface (contact surface) of the fastened member. The operation can be performed.

  The bolt of 1 of the present invention is inserted from the main screw portion side through the bolt holes of several to-be-fastened members into a plurality of overlapped members to be fastened, and the main screw portion is disposed on the rear side. Screwed into the female thread portion of the fastened member, or screwed into the other nut member disposed through the bolt holes of all the fastened members, and using the bolt head, When the screw is further screwed in, the nut member screwed into the auxiliary screw portion also advances to the fastened member side along with the screwing, and eventually the back surface side of the nut member comes into contact with the front surface of the fastened member. After this, usually, even if the screwing operation of the main screw part is continued using the bolt head, the nut member is caused by friction between the back surface and the seating surface (contact surface) of the fastened member, The rotation will remain stopped. The screw member rotation operation is performed while the rotation of the nut member is stopped.

  Exceptionally, the seating surface of the fastened member is a highly smooth surface due to its material, surface condition, and other conditions, and the nut member rotates with them by the screwing rotation operation of the bolt member including the main screw part. However, in such a case, the bolt member is screwed and rotated while stopping the rotation of the nut member using a wrench or other tool.

  In this way, when the screwing operation is further performed without rotating the nut member, the torque required for the screwing is smaller than that in the case of a normal conventional bolt having a pitch similar to the helical pitch of the main screw portion. Torque. Further, as described above, since the nut member can be screwed and fastened without rotating, there is a risk of causing a flaw on the seat surface (contact surface) of the foremost to-be-fastened member that contacts the back side of the nut member. Nor. Further, since the nut member in contact with the seating surface (contact surface) of the member to be fastened is not rotated, unnecessary force for resisting the frictional force and the like generated thereby is not required.

  According to the bolt 1 of the present invention, as described above, when fastening the fastened member, the bolt member is fastened after the back surface of the nut member comes into contact with the seat surface of the fastened member on the front side. As described above, the required torque is smaller than that of a conventional bolt having the same pitch as the helical pitch of the main screw portion. This is based on the premise that the nut member is not rotated as described above.

In this case, the torque of the bolt 1 of the present invention is such that the spiral pitch of the auxiliary screw portion is shorter than the spiral pitch of the main screw portion. Therefore, when the bolt member is tightened and rotated, the bolt member moves per unit rotation speed. With respect to the amount, the amount of movement is reduced because the amount of movement of the nut member screwed into the auxiliary screw portion is reduced.
More specifically, the torque required for rotational tightening of the bolt member in this case is proportional to the ratio of the amount of movement of the nut member in the same case to the amount of movement of the bolt member due to tightening rotation. That is, the torque in the above case of this bolt is compared with the torque in the same case of the conventional bolt having the same pitch as the helical pitch of the main screw portion, and the amount of movement of the nut member relative to the amount of movement of the bolt member. That is, the value is reduced to a value corresponding to the ratio.

This torque is as shown in Equation 1 below.

  From the above formula 1, if the difference between the spiral pitch of the main screw portion and the spiral pitch of the auxiliary screw portion is small, the amount of movement of the nut member is small, and if the difference of pitch is large, the amount of movement of the nut member is It turns out that becomes large. Therefore, if the pitch difference is reduced, the ratio of the pitch difference to the spiral pitch of the main screw portion is reduced, the torque required for tightening the bolt of the present invention is reduced, and the pitch difference is increased. As the ratio increases, the torque required for tightening the bolt of the present invention increases. As described above, when the torque is reduced, the amount of movement of the nut member decreases, but this torque and amount of movement is that after the back surface side of the nut member comes into contact with the front surface of the fastened member. Until this contact occurs, the main screw moves at a helical pitch. Therefore, unless the pitch of the helix of the auxiliary screw portion is made extremely close to the pitch of the helix of the main screw portion, the difference in the amount of movement is a slight difference in work. Almost no problem.

  The above formula 1 is the conventional bolt head back surface and the seating surface (contact surface) of the member to be fastened, the back surface of the nut member of the bolt 1 of the present invention and the seating surface (contacting surface) of the member to be fastened. Indefinite elements such as friction between the female screw and the auxiliary screw portion of the nut member of the bolt 1 of the present invention are not considered.

  According to the bolt 2 of the present invention, since the pitch of the auxiliary screw portion is set to 20 to 90% of the pitch of the main screw portion, the tightening torque is reduced to 80 to 10%, and the nut member The amount of movement (the amount of movement per unit rotation of the bolt member) can be appropriately maintained, and the number of rotations until the bolt member is completely tightened can be prevented from being unnecessarily increased.

(a) Sectional drawing of the volt | bolt of an Example, (b) The top view. Sectional drawing which shows the state which couple | bonded two to-be-fastened members with the volt | bolt of an Example. (a) Sectional drawing of the bolt of a prior art example, (b) The top view. Sectional drawing which shows the state which couple | bonded two to-be-fastened members with the volt | bolt of a prior art example.

  A mode for carrying out the present invention will be described based on an embodiment with reference to the drawings.

<Example 1>
As shown in FIGS. 1 (a), 1 (b) and 2, the bolt of the first embodiment is basically a bolt member 3 having a main screw portion 1 at the lower portion and an auxiliary screw portion 2 at the upper portion. And a nut member 4 screwed into the auxiliary screw portion 2 of the bolt member 3.

  The helical pitch of the auxiliary screw part 2 is shorter than the helical pitch of the main screw part 1. In the first embodiment, specifically, the spiral pitch of the main screw portion 1 is 2 mm, and the spiral pitch of the auxiliary screw portion 2 is 1.5 mm. In addition, the diameters of the main screw portion 1 and the auxiliary screw portion 2 of Example 1 were 16 mm.

  The bolt member 3 includes the main screw portion 1 and the auxiliary screw portion 2 described above as main components. As shown in FIGS. 1A and 2, the main screw portion 1, the auxiliary screw portion 2, and the like. The continuous part 5 without a spiral is interposed between the two. The continuous portion 5 is configured to have a diameter equal to or less than that of the main screw portion 1 and the auxiliary screw portion 2 so as to be able to pass through a bolt hole that allows one or both of the main screw portion 1 and the auxiliary screw portion 2 to pass therethrough. To do. In Example 1, the diameter of the continuous portion 5 is 16 mm.

  Further, as shown in FIGS. 1A, 1B and 2, the bolt member 3 constitutes a bolt head 6 at the uppermost portion thereof, that is, above the auxiliary screw portion 2. The bolt head 6 is formed in a general hexagonal shape as seen from the plane as shown in the figure, and the size thereof is screwed into the auxiliary screw part 2 as shown in the figure. The nut member 4 to be joined can be passed without any inconvenience.

  The nut member 4 is a member that can be screwed into the auxiliary screw portion 2 and has a female screw portion with the same pitch on the inner periphery thereof, and the main screw portion 1 of the bolt member 3 is arranged on the lower side or the rear side. When the back surface side of the nut member 4 comes into contact with the upper surface or the front surface (seat surface) of the fastened member 8 when screwed into the female threaded portion 9 of the fastened member 7, friction is caused between them. It is a member that does not rotate by itself.

  The above description is based on the assumption that the fastened members 7 and 8 of the example are to be fastened, and that the fastened member 7 on the lower side or the back side has the female screw portion 9, but for example, a plurality of fastened members Only has a bolt hole, and another nut member is arranged in the back, the bolt member 3 is extended from the front side to the back side through the bolt hole, and the main screw portion 1 is screwed with the other nut member behind. Of course, there are cases where they are combined. Also in such a case, after the back surface side of the nut member 4 comes into contact with the seating surface (contact surface) of the fastened member on the front surface side, the nut member 4 does not rotate by friction with them.

  Depending on the surface condition and material of the part that becomes the seating surface of the fastened member 8, the nut member 4 may be easily rotated. In this case, the nut member 4 is used by being held by a spanner so as not to rotate. To do.

  All the above components are made of metal in the first embodiment, but plastics or other suitable materials may be adopted depending on the application.

  Below, the case where the two to-be-fastened members 7 and 8 are joined with the volt | bolt of this Example 1 is demonstrated.

  As shown in FIG. 2, the fastened member 7 is a member provided with a flat upper surface and a female screw portion 9 that opens to the flat upper surface. Moreover, the to-be-fastened member 8 is a plate-shaped member, and is a member which opened the bolt hole 10 penetrated up and down. This is an example in which the member to be fastened 8 is placed on the flat upper surface of the member to be fastened 7 by the bolt of Example 1 and fastened in that state.

  As described above and shown in FIG. 2, the member 8 to be fastened is placed on the upper surface of the member 7 to be fastened, and the latter bolt hole 10 is positioned on the former female thread portion 9 so as to correspond vertically. The bolt of Example 1 is inserted into the bolt hole 10 of the upper fastening member 8 from the main screw part 1 side of the bolt member 3 and lowered to the top of the female screw part 9 of the lower fastening member 7, The main screw portion 1 is screwed into the female screw portion 9. This screwing operation is performed using the uppermost hexagonal bolt head 6 with an appropriate tool such as a spanner.

  The screwing operation is performed by rotating the bolt head 6 in a predetermined direction using an appropriate tool such as a spanner, as in the conventional bolt. When the bolt member 3 is screwed and rotated in this manner, it goes without saying that the nut member 4 screwed into the auxiliary screw portion 2 rotates in exactly the same manner as the rotation, and the movement of the nut member 4 is also the bolt member. 3 is performed in exactly the same way as the movement in the downward direction. Therefore, it can be said that the bolt of the first embodiment operates in the same manner as the conventional bolt 23, which will be described later, with the same pitch as the helical pitch of the main screw portion 1 until this stage. The difference is that the back surface of the nut member 4 comes into contact with the seat surface (upper surface) of the upper member 8 to be fastened.

  After repeating the above screwing rotation operation, as described above, after the back surface of the nut member 4 comes into contact with the seat surface (upper surface) of the upper member 8 to be fastened, the material or surface of the member 8 to be fastened The nut member 4 stops rotating due to a frictional force between the nut member 4 and the seat surface except for a special smooth surface depending on conditions such as the state. This bolt continues the screwing rotation of the bolt member 3 using the upper bolt head 6 while the rotation of the nut member 4 is stopped as described above.

  When the seat surface of the member to be fastened 8 is exceptionally a special smooth surface and the nut member 4 rotates with the rotation of the bolt member 3, the tool member such as a spanner is used. While maintaining the state where the rotation of the nut member 4 is stopped, the screw bolt rotation is continued using the uppermost bolt head 6.

  Thus, after the nut member 4 abuts against the seating surface of the fastened member 8, the rotation of the nut member 4 normally stops automatically (because it is forcibly stopped when it does not stop exceptionally). The amount of movement of the nut member 4 in the downward direction is reduced to the difference between the helical pitch of the main screw portion 1 and the helical pitch of the auxiliary screw portion 2. In the first embodiment, as described above, the spiral pitch of the main screw portion 1 is set to 2 mm, and the spiral pitch of the auxiliary screw portion 2 is set to 1.5 mm. The nut member 4 moves downward by 0.5 mm. The torque for screwing and rotating the bolt member 3 in this case is about ¼ when compared with the case where the bolt is fastened by the conventional bolt 23 having the same pitch as the helical pitch of the main screw portion 1 when calculated by the above equation (1). It becomes the size of.

  Of course, in this case, as described above, the amount of movement of the nut member 4 is ¼ of the amount of movement of the bolt member 3, so that the number of rotations of tightening until the completion of tightening increases. In addition, such an operation is performed after the back surface of the nut member 4 comes into contact with the seating surface of the member to be fastened 8, and therefore an actual increase in the number of tightening rotations is so slight that it cannot be realized.

  Therefore, according to the bolt of the first embodiment, as described above, the nut member 4 does not rotate after the back surface side of the nut member 4 comes into contact with the seat surface of the member 8 to be fastened. It is possible to avoid the possibility of causing scratches on the seat surface due to the rotation and sliding of the nut member 4 and to avoid the positional shift that may occur due to the surface shape of the fastened member 8. Instability of the tightening force by the bolt can be avoided. Further, the rotation of the nut member 4 is stopped, and the amount of movement of the nut member 4 after contact with the seating surface of the fastened member 8 is reduced, so that the torque required for the tightening rotation of the bolt member 3 is reduced. Become.

  Hereinafter, the above-described Example 1 and additional Examples 2 and 3 are compared with the conventional bolt 23, and the results are shown.

<Examples 2 and 3>
The second and third embodiments have basically the same configuration as the first embodiment described above, and only the helical pitch of the auxiliary screw portion 2 is different. In Example 2, the pitch of the auxiliary screw part 2 is set to 1.0 mm, and in Example 3, it is set to 0.5 mm. Of course, it goes without saying that the pitch of the female thread portion of the nut member 4 is also set in the same manner. The bolts of Examples 2 and 3 can also be used for fastening the members to be fastened 7 and 8 in the same manner as the bolts of Example 1. The basic effects in this case are the same as those in the first embodiment, but are slightly different in quantity. The amount of movement of the nut member 4 and the torque required for tightening rotation of the bolt head 6 after the time when the back surface of the nut member 4 contacts the upper surface of the fastened member 8 are different from those of the bolt of the first embodiment as will be described later. .

<Conventional bolt for comparison>
As shown in FIGS. 3A, 3B and 4, the conventional bolt 23 to be compared is positioned between the screw portion 21, the bolt head portion 26, and the screw portion 21 and the bolt head portion 26. The screw portion 21 is configured to have a pitch of 2 mm which is the same pitch as the main screw portion 1 of the bolts of the first, second, and third embodiments. A general head shape of a plane hexagon having a larger diameter than the screw portion 21 is used. The diameter of the screw portion 21 is 16 mm, which is the same as that of the main screw portion 1 of the bolt of the first embodiment, and the diameter of the continuous portion 25 is also 16 mm.

  For convenience of comparison with the bolts of the first, second, and third embodiments, an example in which the above conventional bolt 23 is used for fastening the same fastened members 7 and 8 will be described.

  As shown in FIG. 4, the member 8 to be fastened is placed on the upper surface of the member 7 to be fastened, and the latter bolt hole 10 is positioned on the former female screw portion 9 so as to correspond vertically. Is inserted into the bolt hole 10 of the upper fastening member 8 from the screw portion 21 side and lowered to the top of the female screw portion 9 of the lower fastening member 7, and the screw portion 21 is moved to the female screw portion 9. Screw in and tighten. This screwing and tightening operation is performed using the upper hexagonal bolt head 26 with an appropriate tool such as a spanner. The tightening of the bolt head 26 is repeated as many times as necessary to complete the tightening.

  In the following, when the fastened members 7 and 8 are fastened in the same manner as described above for the bolts of the first embodiment with the bolts of the first, second, and third embodiments, the back surface of the nut member 4 is covered. Table 1 shows the torque required for tightening rotation of each bolt and the amount of movement of the nut member 4 after the point of contact with the seating surface of the fastening member 8 for comparison. The torque is shown as a ratio to the torque required for the conventional bolt 23 in the same case.

  As shown in Table 1 above, after the nut member 4 abuts against the seating surface of the fastened member 8, Examples 1, 2, and 3 require screwing as compared with the conventional bolt 23 of the comparative example. Torque is reduced. The torque decreases as the pitch of the auxiliary screw portion 2 approaches the pitch of the main screw portion 1. On the other hand, since the amount of movement of the nut member 4 becomes small, the amount of screwing of the bolt member 3 correspondingly increases. This is because the nut member 4 contacts the seating surface of the fastened member 8 as described above. Since it is after the contact, unless the pitch of the auxiliary screw portion 2 is made extremely close to 2 mm of the pitch of the main screw portion 1, the actual increase in screwing amount is slight. Is not enough to realize.

  According to the bolt of the present invention, it can be used in the field of bolt manufacture, various machines and devices using the bolt, and other fields of manufacture.

DESCRIPTION OF SYMBOLS 1 Main screw part 2 Auxiliary screw part 3 Bolt member 4 Nut member 5 Continuous part 6 Bolt head 7 Back side or downward to-be-fastened member 8 Front or upper to-be-fastened member 9 Back or lower to-be-fastened member female screw Part 10 Bolt hole of fastening member on the front side or upper side 21 Screw part of conventional bolt 23 Conventional bolt 25 Continuous part of conventional bolt 26 Bolt head of conventional bolt

Claims (2)

A size in which a main screw portion is provided at the lower portion, an auxiliary screw portion having a helix having a shorter pitch than the helix is provided above the main screw portion, and a nut member screwed on the auxiliary screw portion can be passed above the auxiliary screw portion. A bolt member having a bolt head of
A nut member screwed into the auxiliary screw portion of the bolt member;
Bolt composed of   The bolt according to claim 1, wherein the spiral pitch of the auxiliary screw portion is set to a size of 20 to 90% of the spiral pitch of the main screw portion.

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