JP2005061442A - Hexagonal nut with flange and bolt nut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hexagonal nut having a flange embodied in a simple configuration and provide a bolt nut using it, capable of eliminating necessity for precluding a slack by the use of any separate member by equipping the hexagonal nut itself with the slack preventing function. <P>SOLUTION: The hexagonal nut 1 with the flange having a bolt inserting hole 14 where female threads are formed has a flange part 13 on the seat face of its nut body 11 having a hexagonal shape on the plan is furnished with a cylindrical wall 16 having a height approximately equal to two pitches of the female threads which is formed rigidly on the side with the seat face 13 in the bolt inserting hole 14 and has a cylindrical inner wall shape having approximately the same diameter as the nominal diameter d1 of the female threads 15a, wherein the distribution of the seat face pressure on the seat face 13 at the time of being fastened is made dispersing on the periphery of the seat face 13 in such a way as approximately symmetrical about the axis. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flanged hex nut having a function of preventing looseness, and a bolt nut comprising the flanged hex nut and a hex bolt.
[0002]
[Prior art]
Bolts and nuts (bolt nuts) are widely used as means for fastening and fixing a plurality of members (members to be tightened). For example, a flanged hexagonal nut as shown in FIG. 4 is often used as a nut when the member to be tightened is in a condition where it can easily vibrate. In the flanged hexagon nut 100 shown in this figure, a flange portion 102 having a larger diameter than the nut body 101 is formed on the seat surface 104 side of the nut body 101 having a hexagonal shape in plan view. Reference numeral 103 denotes a bolt insertion hole in which an internal thread 103a is formed.
[0003]
Such a flanged hex nut can secure a wider area of the seating surface, that is, a contact area with the member to be tightened than a normal hex nut. it can. Nevertheless, loosening due to long-term use is unavoidable, which may cause accidents, and maintenance such as regular tightening is often necessary.
[0004]
There are two types of loosening as described above.
One of them occurs when there is a minute uneven part or shape error that occurred during processing, and local plastic deformation proceeds due to the influence of external force after tightening and the uneven part is flattened. Looseness caused by contact sag or fine wear. Such loosening occurs even though the nut does not return and rotate. The other is looseness that occurs when the nut returns and rotates due to vibration or impact external force.
[0005]
The former type of looseness can be prevented relatively easily by taking measures such as improving the machining accuracy of bolts and nuts, or using a material with high wear resistance. On the other hand, for the latter type of loosening, measures such as providing a caulking portion as described in Patent Document 1, or using a third member different from the bolt and nut as a loosening prevention member, etc. In most cases, was applied. Therefore, the configuration becomes complicated, and as a result, there is a problem that durability of the bolt and nut is lowered.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-99124
[Problems to be solved by the invention]
As described above, the cause of loosening due to the bolt or nut returning and rotating is that the bolt or nut seat surface pressure is non-axisymmetrically distributed, and the nut returns due to axial vibration. This is thought to be due to the rotational action.
However, these non-axisymmetric distributions of the seating surface pressure are not only caused by manufacturing errors of the seating surfaces of the bolts and nuts or the contact surfaces thereof, but are also fatal due to the configuration of the bolts and nuts themselves. This has been confirmed by the inventors' investigation. That is, the male screw and the female screw formed on the bolt and nut are formed in a spiral and non-axisymmetric shape in function, and as a result, the pressure distribution such as the seating surface pressure also has non-axisymmetricity, Circumferential distribution is not uniform.
[0008]
For these reasons, it is considered that a sufficient loosening prevention effect can be obtained if the pressure on the seating surface or the like can be distributed axisymmetrically.
[0009]
The present invention has been made in view of the above circumstances, the flanged hexagon nut itself has a function of preventing loosening, and it is not necessary to prevent loosening using another member, etc., and the flanged hexagonal nut has a simple configuration, And it aims at providing the bolt nut using this.
[0010]
[Means for Solving the Problems]
The invention according to claim 1 is a hexagon nut with a flange having a flange portion on a seat surface side of a nut body having a hexagonal shape in plan view and having a bolt insertion hole in which a female thread is formed. A cylindrical wall portion having a cylindrical inner wall shape having a diameter substantially the same as the nominal diameter of the female screw and having a height corresponding to approximately two pitches of the female screw is formed on the seat surface side, and the seating surface pressure of the seat surface during tightening The distribution is distributed on the outer peripheral side of the seating surface and is distributed approximately axisymmetrically.
[0011]
Thus, since the cylindrical wall portion having a height corresponding to approximately two pitches of the female screw is formed on the seat surface side in the bolt insertion hole, when the hexagon nut with flange is screwed to the bolt, The pressure distribution of the seating surface that is a contact surface with the fastened member can be distributed to the outer peripheral side and can be axisymmetric. For this reason, the pressure distribution on the seating surface is non-uniform so that the seating surface pressure is biased and the generated rotational force can be eliminated or eliminated, and the pressure is distributed to the outer peripheral side. The frictional resistance moment of the surface can be increased. Thereby, loosening of a hexagon nut with a flange can be prevented exactly. Moreover, the maximum shape factor of the external thread of the bolt screwed into the flanged hex nut can be reduced.
[0012]
The invention according to claim 2 is the hexagon nut with flange according to claim 1, wherein the outer diameter of the flange portion is approximately twice the nominal diameter of the female screw, and the two-surface width of the nut body is , Approximately 1.5 times the nominal diameter, and an inclination angle of the flange upper surface of the flange portion with respect to the seat surface is approximately 45 °, and a height from the seat surface to a position where the flange upper surface and the nut body intersect with each other. This is characterized by approximately three pitches of the female screw.
[0013]
By setting the dimensions such as the outer diameter of the flange, the width of the two faces of the nut body, the angle of inclination of the flange upper surface, and the height to the position where the flange upper surface and the nut body meet, the bearing surface pressure distribution is set in this way. Can be more accurately distributed and symmetric with respect to the axis, and loosening of the hexagon nut with flange can be prevented more accurately.
[0014]
According to a third aspect of the present invention, the flanged hexagon nut according to the first or second aspect and a head portion having a hexagonal shape in plan view are provided on one end side of the shaft portion on which the male screw is formed. A bolt nut comprising a hexagon bolt screwed to a flanged hexagon nut.
[0015]
When such a bolt and nut is used to fasten and fix the member to be fastened, the member to be fastened is sandwiched between the seating surface of the hexagon nut with flange and the seating surface of the head of the hexagon bolt. At this time, the bearing surface pressure distribution of the hexagon nut with flange is distributed to the outer peripheral side and is axisymmetric distribution as described above. And the bearing surface of the hexagon nut with a flange and the bearing surface of a hexagon bolt head press the to-be-fastened member with the same force by the law of action and reaction. That is, on the seating surface of the hex bolt head, the rotational force generated by the non-uniform pressure distribution is eliminated or eliminated, and the frictional resistance moment of the seating surface increases due to the distribution of the pressure to the outer peripheral side. Has been. Thereby, not only the looseness on the flanged hexagon nut side but also the looseness on the hexagon bolt side can be prevented accurately.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.
In FIG. 1, the hexagon nut with a flange which has a loosening prevention function based on this embodiment is shown. This flanged hexagon nut 1 has a flange portion 12 having a flange diameter (outer diameter of the flange portion) d3 on the seat surface 13 side of the nut body 11 having a hexagonal shape in plan view (dual width is d2). The bolt insertion hole 14 is formed with a female screw 15a.
[0017]
The flange portion 12 has a flange diameter d3 and a flange thickness hc, and the flange upper surface 12f is formed in a truncated cone shape with an inclination angle θ with respect to the seat surface 13. The flange upper surface 12f and the six side surfaces of the nut body 11 are in contact with each other by forming an arc-shaped intersection line, and this intersection line is at a substantially central position (midpoint) in the lateral direction of the nut body 11. The height from the seating surface 13 is the highest. This upper end point (upper end position) is shown as an intersection point I, and the height from the seating surface 13 to this intersection point I is shown as a flange upper end height hf.
[0018]
Most of the bolt insertion hole 14 from the upper end side is a female screw portion 15 in which a female screw 15a having a pitch P is formed. On the side of the seat surface 13 in the bolt insertion hole 14, a cylindrical wall portion 16 having a cylindrical inner wall shape having the same diameter as the nominal diameter d1 of the female screw 15a and a height (cylinder wall height) hs is provided. It is formed so as to continue to the portion 15. The cylindrical wall portion 16 is the same portion as the female screw 15a is cut by a predetermined length, that is, the cylindrical wall height hs, and is formed into a bolt when the bolt is screwed into the bolt insertion hole 14. Only the top part of the threaded female thread is in linear contact. The cylindrical wall portion 16 has a function of facilitating insertion of the bolt 2 and distributing the seat surface pressure distribution of the seat surface during tightening to the outer peripheral side of the seat surface 13 so as to be distributed almost symmetrically. doing.
[0019]
The cylinder wall height hs and the pitch P of the female screw 15a are set so as to have a relation of the following expression (1).
hs = 2P Formula (1)
Thus, if the cylinder wall height hs of the cylinder wall portion 16 is about two pitches of the female thread 15a, the seating surface pressure distribution on the seating surface 13 when screwed with the bolt is obtained. It can be distributed on the outer peripheral side and distributed axisymmetrically. As a result, the frictional resistance moment of the seat surface 13 is increased by eliminating and eliminating the rotational force of the flanged hexagon nut 1 generated by the uneven distribution of the seat surface pressure and by distributing the seat surface pressure to the outer peripheral side. Together with the two actions, the action of preventing loosening can be obtained.
[0020]
When the cylinder wall height hs of the cylinder wall portion 16 is shorter than two pitches, for example, if it is about one pitch, the seating surface pressure distribution is not axisymmetrically distributed. Since it concentrates on the circumferential side, that is, in the vicinity of the lower part of the screw, the bolt or nut rotating action due to the uneven distribution of the bearing surface pressure cannot be sufficiently eliminated or eliminated. On the other hand, if the cylinder wall height hs is longer than 2 pitches, for example, about 4 pitches, then the seating surface pressure is uniformly distributed over the entire range of the seating surface. As a result, the frictional resistance moment of the seating surface is reduced, and the effect of preventing loosening due to the frictional force cannot be obtained sufficiently.
For this reason, it can be said that the cylinder wall height hs of the cylinder wall part 16 for providing a sufficient loosening prevention function is a length corresponding to approximately two pitches of the female screw 15a. This has been found by the inventors of the present application as a result of independent studies.
[0021]
Further, as a result of the study by the inventors of the present application, by using the flanged hexagon bolt 1 in which such a cylindrical wall portion 16 is formed, it is compared with the case where a normal flanged hexagon bolt without a cylindrical wall portion is used. It has been found that the maximum shape factor of the male screw in the bolt to be screwed can be reduced by about 20%. That is, excessive stress concentration on the male screw is less likely to occur, so that deformation, sag, and breakage of the male screw can be suppressed, and the durability of the bolt can be greatly improved and the life can be extended. .
[0022]
It has already been demonstrated by the inventors of the present invention that a sufficient loosening prevention effect can be obtained by forming a cylindrical wall portion having a height corresponding to approximately two pitches of the female screw in such a normal hex nut. ing. And when this application applies such a structure to a hexagon nut with a flange, by setting each dimension in this hexagon nut with a flange to be predetermined, it can be expected that a more suitable and even greater loosening prevention effect can be expected. I found it. This will be described below.
[0023]
In the flanged hexagon nut 1, the dimensions such as the inclination angle θ, the nominal diameter d1, the two-sided width d2, the flange diameter d3, the cylinder wall height hs, the flange upper end height hf, and the pitch P are substantially the following. Each is set so as to have the relationship shown in Expression (2) to Expression (5).
d3 = 2d1 Formula (2)
d2 = 1.5d1 Formula (3)
θ = 45 ° Formula (4)
hf = hs + P = 3P (5)
In addition, from the formula (4), the flange thickness hc is given by the following formula (6).
hc = hf − ((d3−d2) / 2) (6)
[0024]
By setting in this way, the above two actions, that is, the action of eliminating and eliminating the rotational force of the flanged hexagon nut 1 caused by the uneven distribution of the seating surface pressure, and the distribution of the seating surface pressure to the outer peripheral side. Thus, the effect of increasing the frictional resistance moment of the seating surface 13 can be more accurately achieved, and an even greater loosening prevention effect can be obtained.
[0025]
FIG. 2 shows a state where the members to be tightened 31 and 32 are fastened and integrally connected and fixed by the bolt nut A composed of the hexagon nut 1 with flange and the hexagon bolt 2. The hexagon bolt 2 used here is provided with a head portion 22 having a hexagonal shape in a plan view on one end portion side of a shaft portion 21 on which a male screw 21a is formed, and is screwed into the hexagon nut 1 with a flange. Yes.
[0026]
The to-be-tightened members 31 and 32 have through holes 31h and 32h penetrating in the thickness direction, and the shaft portion 21 of the hexagon bolt 2 is inserted into the through holes 31h and 32h. These to-be-tightened members 31 and 32 are sandwiched between the seat surface 23 of the head portion 22 of the hexagon bolt 2 and the seat surface 13 of the flanged hexagon nut 1 screwed into the shaft portion 21 of the hexagon bolt 2. Tightly fixed to.
[0027]
Here, as described above, the pressure distribution on the seating surface 13 of the flanged hexagon nut 1 is distributed to the outer peripheral side and has an axisymmetric distribution. The pressure distribution on the seating surface 23 of the screwed hexagon bolt 2 is also distributed to the outer peripheral side and is axisymmetric distribution by the law of action and reaction. That is, even on the hexagon bolt 2 side, the pressure distribution on the seating surface 23 is non-uniform, so that the seating surface pressure is biased and the rotational force generated thereby can be eliminated or eliminated, and the pressure The frictional resistance moment of the seating surface 23 can be increased by the distribution to the outer peripheral side. Thereby, loosening of the bolt nut A is prevented accurately.
[0028]
A comparison by a photoelastic method between the conventional flanged hexagon nut 100 and the flanged hexagon nut 1 is shown in FIGS. This photoelasticity method is a method of creating a model with a specific polymer material such as epoxy resin, slicing it to a thickness of about 3 mm after applying a load, and looking at this slice piece through polarized light to examine the stress distribution state. It is a measurement method. In other words, when viewed through polarized light, the stress distribution state appears as a density of striped patterns. By analyzing this pattern, the stress distribution state can be visually examined. 3A and 3B are photographs (photoelastic photographs) taken at this time.
[0029]
In these photographs, the dark colored portion is the portion where the contact pressure is concentrated, and such a pressure concentrated portion is indicated by the symbol F. From these figures, it can be seen that the pressure of the flanged hex nut 1 is dispersed on the outer peripheral side as compared with the pressure of the conventional flanged hex nut 100.
[0030]
In the hexagon nut 1 with flange according to the present embodiment, the cylindrical wall portion 16 having a cylindrical wall height hf corresponding to approximately two pitches of the female screw 15a is formed on the seat surface 13 side in the bolt insertion hole 14. When the flanged hexagonal nut 1 is screwed to the bolt, the pressure distribution of the seating surface 13 serving as the contact surface with the member to be fastened can be distributed to the outer peripheral side and can be axisymmetric. . For this reason, the pressure distribution on the seating surface 13 is non-uniform so that the seating surface pressure is biased, and the rotational force generated thereby can be eliminated or eliminated, and the pressure is distributed to the outer peripheral side. Thus, the frictional resistance moment of the seating surface can be increased. Thereby, rotation with respect to the to-be-clamped member 31 of the hexagon nut 1 with a flange can be prevented, and loosening can be prevented exactly. Thus, since the flanged hexagon nut 1 has a function of preventing loosening, it is not necessary to prevent loosening using a separate member, and it is possible to accurately prevent loosening while simplifying the configuration. .
[0031]
Moreover, by using this hexagon nut 1 with a flange, the maximum shape factor of the external thread of the bolt to be screwed can be reduced by about 20%. That is, excessive stress concentration on the male screw is less likely to occur, so that deformation, sag, and breakage of the male screw can be suppressed, and the durability of the bolt can be greatly improved and the life can be extended. .
[0032]
Further, the dimensions such as the inclination angle θ, the nominal diameter d1, the two-sided width d2, the flange diameter d3, the cylinder wall height hs, the flange upper end height hf, and the pitch P are expressed by the equations (2) to (5). By setting as described above, dispersion and axial symmetry of the bearing surface pressure distribution can be achieved more accurately, and loosening of the flanged hexagon nut 1 can be prevented more accurately.
[0033]
Further, when the fastened members 31 and 32 are fastened and fixed using the bolt nut A composed of the hexagon nut 1 with flange and the hexagon bolt 2, the seat surface 13 of the hexagon nut 1 with flange and the hexagon bolt 2 are fixed. The fastened members 31 and 32 are held between the seating surface 23 of the head 22. At this time, the bearing surface pressure distribution of the flanged hexagon nut 1 is distributed to the outer peripheral side and is axisymmetric. And the bearing surface of the hexagon nut with a flange and the bearing surface of a hexagon bolt head press the to-be-fastened member with the same force by the law of action and reaction. That is, on the seating surface of the hexagon bolt head, the rotational force generated by the non-uniform pressure distribution is eliminated or eliminated, and the frictional resistance moment of the seating surface is increased by the distribution of the pressure to the outer peripheral side. Has been. As a result, not only the loosening on the flanged hexagonal nut 1 side but also the looseness on the hexagonal bolt 2 side can be prevented accurately.
[0034]
Moreover, since the maximum shape factor of the male screw 21a of the hexagon bolt 2 can be reduced by about 20% as described above, deformation, sag, breakage, etc. of the male screw 21a can be suppressed, and the hexagon bolt 2 As a result, it is possible to significantly improve the durability of the steel plate and to prolong the service life, and to obtain an advantageous effect on the screw strength.
[0035]
【The invention's effect】
As described above, the flanged hexagonal nut according to the present invention employs the above-described configuration, so that the flanged hexagonal nut itself has a function of preventing loosening and prevents loosening by using another member. There is no need to perform the above, and a simple configuration can be achieved.
Further, in the bolt nut using the hexagonal nut with flange and the hexagonal bolt, the maximum shape factor of the male screw of the hexagonal bolt can be reduced by about 20%, so that deformation or breakage of the male screw is suppressed. Therefore, the durability of the hexagon bolt can be greatly improved, the life can be extended, and an advantageous effect on the screw strength can be obtained.
[Brief description of the drawings]
FIG. 1 is a view showing an embodiment of a hexagon nut with a flange according to the present invention, in which (a) is a plan view and (b) is a partial sectional side view.
2 is a side cross-sectional view showing when the flanged hexagon nut and the hexagon bolt shown in FIG. 1 are tightened. FIG.
3A is a photoelastic photo showing the stress distribution state of a conventional flanged hex nut, and FIG. 3B is a photoelastic photo showing the stress distribution state of the flanged hex nut according to one embodiment of the present invention. is there.
4A and 4B are views showing an example of a conventional flanged hexagon nut, where FIG. 4A is a plan view and FIG. 4B is a side sectional view.
[Explanation of symbols]
A Bolt nut 1 Hexagon nut with flange 11 Nut body 12 Flange portion 13 Seat surface 14 Bolt insertion hole 15 Female thread portion 15a Female screw 16 Tube wall portion 2 Hexagon bolt 21 Shaft portion 21a Male screw 22 Head portion 23 Seat surface d1 Nominal diameter d2 Two surfaces Width d3 Flange diameter (outer diameter of flange)
hf Flange top edge height hs Tube wall height hc Flange thickness I Intersection point P Pitch

Claims (3)

In a hexagonal nut with a flange having a flange portion on the seat surface side of the nut body having a hexagonal shape in plan view and having a bolt insertion hole in which an internal thread is formed, the female screw is called on the seat surface side in the bolt insertion hole. Forming a cylindrical wall having a cylindrical inner wall shape having substantially the same diameter as the diameter and having a height corresponding to approximately two pitches of the female screw;
A flanged hex nut, wherein a seating surface pressure distribution of the seating surface at the time of tightening is distributed on the outer peripheral side of the seating surface and is distributed approximately axisymmetrically. The outer diameter of the flange portion is approximately twice the nominal diameter of the female screw,
The width of the nut body is approximately 1.5 times the nominal diameter,
An inclination angle of the flange upper surface of the flange portion with respect to the seating surface is approximately 45 °,
2. The hexagon nut with flange according to claim 1, wherein a height from the seat surface to an upper end position at an intersection line between the upper surface of the flange and the nut body is set to approximately three pitches of the female screw. Hexagon nut with flange according to claim 1 or claim 2,
A bolt nut comprising a hexagonal bolt screwed into the flanged hexagon nut, a head portion having a hexagonal shape in plan view is provided on one end side of the shaft portion on which the male screw is formed.

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