JPS5918564B2 - bolt nut - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bolt nut, and more specifically, it relates to a bolt nut that uses two nuts to prevent loosening and that can lock one nut after tightening. be.

Generally speaking, if the Nand that is screwed onto the bold is a single Nand, it will easily loosen due to continuous or severe vibration even if it is tightly tightened, so it is well known that so-called double Nands are used to prevent this. That's right.

However, even in the case of a double nand, the nut may easily come loose depending on the operating error or the location where it is used.

This is most likely due to not using the correct tightening method.

As an alternative method to prevent the nut from loosening, conventionally, for example, a hole is drilled in the nut and a separate elastic member is engaged with the hole in the nut to prevent the nut from loosening due to frictional resistance. was.

However, although these also have a tightening force when tightening the nut, they have the drawback that they cannot completely prevent the nut from loosening due to vibration.

Generally, when a screw is tightened, a tensile force is generated in the bolt, and a tightening force is applied to the object to be tightened, but the phenomenon in which the tightening force decreases is called "screw loosening."

A typical example of "loosening a screw" is the loosening of a nut relative to a bolt, and over the past many years various attempts have been made to prevent the bolt from loosening.

Furthermore, as is generally known, the tightening torque T required when tightening a Nand to a screw, such as a bolt, has a relationship of T>T' with respect to the loosening torque T' required to return the Nand once tightened. To establish.

``Theoretically, therefore, once a nut is tightened, it should not loosen unless an external force is applied to it.

However, in reality, it often happens that when Bold and Nando rotate, Nando drops out.

The reasons for this are as follows.

That is, when such a phenomenon occurs, more or less vibration or intermittent impact acts, and one static friction coefficient becomes a much smaller dynamic friction coefficient, and the friction coefficient of the thread surface also becomes smaller.

As a result, if even a very small external force acts in the direction of loosening, T'
≦0, and it is conceivable that NAND rotates in the direction of loosening.

Therefore, the measures to prevent or prevent loosening are (1) to use a fine thread, (2) to increase the friction of the bearing surface of the nut, and (3) to increase the coefficient of friction of the threaded surface.

This invention corresponds to (3) above.

The purpose of this invention is to make the bold a double structure and increase the coefficient of friction of the threaded surface.

In addition, the double locking system is configured such that the first NAND is locked by this double structure, and the second NAND is also locked by forming a part that screws together with the first NAND. The purpose of this invention is to provide a bolt nut that prevents loosening.

Embodiments of the present invention will be described below based on the drawings that illustrate the embodiments.

FIG. 1 is a sectional view of a main part of a ball nut showing an embodiment of the present invention.

In the figure, 1 is a bold main body, and this bold main body 1 is configured so that it can be divided into a head side 2 and a separate side 3.

The head side 2 has an acid screw hole 4 drilled in the center from one end toward the inside, and a small diameter threaded portion 5 protruding from the separate side 3 is screwed into the acid screw hole 4. and the separate side 3 constitute one bold main body 1.

The thread pitch of the small diameter threaded portion 5 described above and the pinch of the outer peripheral thread of the bold main body 1 must be different.

It is also desirable that the thread pitch of the small-diameter thread portion be smaller than the thread pinch of the outer circumferential thread.

6 is a bag-shaped lock nand (hereinafter referred to as the first nut) of the first nand, and an acid screw T is provided on the inner periphery thereof.

This acid screw 1 is engraved in the same direction as the screw of the bold main body 1 and with the same pinch.

8 is the main nut of the second NAND (hereinafter referred to as the second NAND), one end of which protrudes, and a male screw 9 is carved on its outer periphery, and the acid screw 1 of the first NAND 6 and the male nut of the second NAND The screw 9 is screwed together.

Reference numeral 10 denotes a joint between the head side 2 and separate side 3 of the bold main body 1, and the joint 10 is located at the center of the second NAND 8.
11 is the separate side 3.
This is a concave groove of a rotating engaging member provided at the end of the holder.

Numerals 12 and 13 are fastening members, and 14 is a through hole in the fastening member.

The locking bolt nut having the above structure is manufactured by first inserting the bold body 1 into the through hole 14 of the tightening fixing members 12 and 13, and then inserting the acid screw 1 of the first nut 6 and the second nut 8 from the opposite side. The male screw 9 is screwed together and tightened with the integrated nut 6.8, and then the separate side 3 is rotated counterclockwise through the groove of the engaging member 11 on the separate side 3 of the bold main body 2, as shown in FIG. As shown, when the joint 10 between the head side 2 and the separate side 3 is rotated to the extent that there is a slight gap, the thread pitch of the second NAND 8 differs across the joint 10 of the bold main body 1, so the friction coefficient of the thread surface changes. The amount increases significantly and is firmly held in the locked state.

This is because the male screw of the second nut 8 is firmly locked by the tightening force a by the male screw on the head side 2 and the tightening force by the male screw on the separate side 3 which is applied in the opposite direction to the tightening force a. It is maintained in

Furthermore, even if one of the nuts 6.8 rotates in the direction of loosening, the accompanying threaded part is threaded into multiple threaded parts, and each of them tries to work in the direction of tightening the nut, so it will not completely loosen. It can be stopped.

This will be explained theoretically below.

Figures 7a and 7b show the bolt and Nand loaded states, and Figure 1a shows the bolt and Nand before locking, and Figure 7
The figure shows the state after locking.

21 is a bolt, 22 is a main nand, and 23 is a lock nand.

The names and symbols of each part in FIG. 1 above are as shown in Table 1.

All screws shall be one right-hand thread.

Therefore, the lead of the screw is equal to a pinch.

Also, 5m °°β”=・”” −−−−−−−−−(1) 5m Stone β”” zdz There is a relationship.

When the lock nand of No. 23 is rotated counterclockwise, in order to produce a locking effect, L t < Lm ・・・・・・・・・・・・
・(2) There is a relationship.

The main nut 22 and the lock nut 23 are fitted together with a locking screw, and the main screw is machined in a state where the two surfaces are in contact with each other, as shown by the thick line in FIG. 1A.

In this state, the integrated NAND is screwed into the male thread of the bolt, and the specified tightening is performed under force Ff.

At that time, the required torque T2f is T2f21/2 (dm (115 μm + tan) + dw
μ.

)Ff......Given by (3).

This state is shown in FIG. 1a. Next, leave the main nut 22 as it is and turn only the locking nut 23 to the left to lock it.

As the lock nut 23 rotates to the left, the main screw in FIG. 1 first comes into contact as shown by the thick line, and the lock nut 23 is lifted along the lead, and the surfaces shown by the chain lines are separated.

Now, since the main screw and the locking screw have the relationship shown in equation (2), the contact shown by the thick line occurs in the locking screw in Figure 1, and the locking screw 23 is prevented from rotating counterclockwise. Ru.

If the locking nand 23 continues to rotate counterclockwise while applying further torque, a locking force Ft is generated, which has the effect of preventing loosening.

The torque T3t required to lock the lock NAND 23 to generate the locking force Ft is T3z=172(dm(1.15μm+janβm)+
az(1,15ttl,,-tanβt))Ft-<4
) is given by

In the state shown in FIG. 1a, the force Fm exerted on the main pad 22 is equal to the tightening force Ff.

When locking the lock nand 23 by turning it counterclockwise, the force Ff of bolt nand original tightening does not change, but Fm
is Fm-Ff+Ft ・・・・・・・・・(5)
It increases based on the relationship between

The fitting length of the main screw with the main nut 22 is designed so that it will not break even if a force 1.5 times Ff is applied.

Furthermore, the length of the main screw that fits with the lock nut 23 is designed so that it will not break even if a force 0.5 times Ff is applied.

Therefore, 9 = 1.5Ff...
・(6) Fl = 0.5 Ff---(7)
can be locked based on the relationship.

Note that equations (6) and (7) satisfy the relationship of equation (5).

Note that the strength of the locking screw is large due to its diameter, so there is no problem as long as it has a certain length of fit.

Substituting equation (7) into equation (4), T 3 t = 1/4 (dm (1,15 turn 1 tan β product) 1 dz (Li2 ttl-tan β t))
Ff” (8).

Regarding the actual tightening force Ff of a bolt, it seems that 70 inches, which is the yield point (or proof stress) σ, of the bolt may be generally used as a guide.

Therefore, if the effective area of the screw is A8, then F(=0,7A8σ1 ・・・・・・・・・(
9).

Next, specifically tighten the lock nut 23 with lock torque T.
An example of calculation of 3t is shown.

Calculations are made for the case where the main screw...MlO (P=1.5) and the locking screw...M16x1.

Here, the effective diameter dm of the main screw is dm=9.0
26 rrrm, then 1.5 janβm-ffX9.026-〇・0529.
If the effective diameter dt of the locking screw is dt=15.350+on, then ■ tanβt-□8□5.35-0・0207 ・Also, the average diameter dw of the seat surface of the main nut is the two opposite sides of the main nut. 22rIr1n1 and the hole diameter is l1
If it is m, then 22+11 dw2□''=16.5 mm.

Therefore, the friction coefficients μm, μt, and μW of the main screw, locking screw, and main nut seating surface are μm−μt−
Since μW20.15, from equation (3) T2f= 1/2 (9,026(1,15X0.15
+0.0529)+16.5 X O,15) F
f = 2,255Ff ・・・・・・・・・
αO) From equation (8), T3t=1/4(9,026(1,15XO,1580
,0529)+15.35 (1,15X0.15-
0.0207))Ff=1.091Ff
・・・・・・・・・(11) Bolt strength classification is 8
．． 8.

σr = 64 kgf/m7 (minimum) AB”58
．． 0rIt1jt From formula (9), Ff = 0.7 x 58
It becomes rr1.

In another embodiment shown in FIG. 2, unlike in FIG. 1, the first nut 6 has one protruding end and a male thread 9 carved on its outer periphery, and the second nut 8 is a cap nut, and its inner periphery is An acid screw 7 is provided.

Further, the joint portion 10 between the head side 2 and the separate side 3, which are mainly bold, is located at the center of the first nut 6.

In FIG. 2, the same members as in FIG. 1 are represented by the same symbols.

In addition, in the case of FIG. 2, the joint 10 between the head side 2 and separate side 3 of the bold main body 1 differs from FIG. It shows the condition.

FIG. 3 is a cross-sectional view of the main parts of the Bold Nand shown in FIG. 2, with each member separated and arranged.

In the above, the rotating member provided at the end of the separate side and the L°C
Although grooves 11 and protrusions 16 have been described, holes 17 may also be used.

The shape of the protrusion 16 may be a rectangle as shown in FIG.
In addition to the hexagonal shape shown in FIG. 6, the shape may be a quadrilateral or other polygonal shape.

As mentioned above, the locking bolt nut according to the present invention has a structure in which the bolt has a double structure, and the nut screwed into this is a double nand, and these nuts are screwed together to lock the two nuts. Because of this, it is possible to obtain a bolt nut that completely prevents loosening, which has never been seen before.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of a ball nut showing one embodiment of the present invention, FIG. 2 is a cross-sectional view of a main part of a ball nut showing another embodiment of the invention, and FIG. 3 is an exploded view of FIG. The partial sectional view, FIG. 4, is an enlarged sectional view of the circular portion A in FIG.
The figure is a plan view showing the shape of the protrusion provided at the separate side end of the bold main body, FIG. 6 is a plan view showing the shape of the hole drilled at the separate side end, and FIGS.
It is an explanatory view showing the load state of the nut. 1...Bold main body, 2...Head side, 3...Separate side, 4...Female screw hole, 5...Small diameter screw Department, 6, 8...Nand's? ...Female screw, 9...Male screw,
11... Concave groove.

Claims (1)

[Scope of Claims] 1. A bold main body that can be separated into a head side and a separate side at any position of the nut tightening position of the outer peripheral screw portion,
A rotating engaging member is provided at the end thereof, and a small diameter screw hole is provided on either the head side or the separate side,
One bold main body that forms a double structure by having a small diameter threaded part protruding from the other side and screwing the small diameter threaded part into this small diameter screw hole, and two parts that are threaded into the outer peripheral screw of the bold main body.
Two nuts, one end of which protrudes, a main nut having a male thread on its outer periphery in the same direction and the same pinch as the threaded portion of the main body of the bold body, and an acid screw to be screwed into the male thread of the main nut. Bold Nand is characterized by being made of bag-shaped rock nuts. 2. The bold nut according to claim 1, wherein the outer peripheral thread of the bold main body and the thread of the small diameter threaded portion are right-handed threads in the same direction. 3. The bold nut according to claim 1 or 2, characterized in that the thread pitch of the outer peripheral thread of the bold main body and the small diameter threaded portion are different by U, -.