JP3532180B2 - Shear torque nut - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shear torque nut for securely fixing a hexagon nut with an appropriate torque.

[0002]

2. Description of the Related Art Conventionally, many fastening structures using a combination of a male screw and a female screw have been used, and a monkey wrench, an eyeglass wrench, a box wrench (socket wrench) or the like is often used as a fastening tool.

The fastening structure using bolts and nuts may loosen due to long-term vibrations after fastening. As a measure for preventing this loosening, a mechanism called a double nut for fastening two nuts to the same bolt is used. Has been.
However, although this double nut is more effective than the case where one nut is fastened, both nuts may gradually loosen due to vibration and eventually come off. Further, since it is necessary to fasten the two nuts separately, the working time naturally takes almost twice.

In order to solve the above-mentioned problems, the actual construction of Sho 61-
In JP-A-150512, as shown in FIGS. 3 (A) and 3 (B), two nut bodies 80 and 81, a connecting portion 82 that connects the nut bodies 80 and 81 are provided near the inside of the connecting portion 82. A double nut 84 having a ring-shaped insert 83 is disclosed. The nut bodies 80 and 81 can be screwed together, and after the continuous portion 82 is broken, the nut bodies 80 and 81 are interposed between the nut bodies 80 and 81 and the nut bodies 80 and 81 and the bolts. The force is applied to each other to prevent the nut bodies 80 and 81 from loosening.

[0005]

However, in the conventional double nut 84 described above, the nut bodies 80, 8 can be formed only by transmitting a force in the axial direction after the intermediate body 83 is broken.
It does not work to increase the fastening force with the bolt 1. Also,
It is difficult to fit the interposer 83 inside the connecting portion 82,
If it protrudes from this point, it may be caught between the bolts and cannot be fastened to a predetermined position.

[0006] Therefore, the problem to be solved by the present invention is
An object of the present invention is to provide a shear torque nut that can easily control the fastening force with a simple structure and reliably prevent loosening.

[0007]

In order to solve the above-mentioned problems, a shear torque nut of the present invention is a torque nut and a shear nut each having a female screw portion of the same size formed radially inward, and the torque nut and the shear nut. An inner side of a rectangular groove section formed between the female screw portions of the shernut, the axial width of which is at least twice the pitch of the female screw portions, and the inner diameter of which is not less than the diameter of the valley of the female screw portions. A groove portion and an outer groove portion that is radially outside of the torque nut and the shear nut and that is formed axially inward of the inner groove portion. The groove bottom surface of the outer groove portion is arranged axially outside. A taper portion whose diameter is gradually reduced toward the shear nut is formed, and an axially inner corner portion of the inner groove portion is located on an extension of the taper portion.

In the present invention, at the time of fastening, when the shear torque nut is screwed into the male screw portion to be screwed and the shear nut is rotated, the torque nut and the shear nut rotate simultaneously. When the shear nut is further rotated after the torque nut comes into contact with the fastening portion, the thin portion formed between the inner groove portion and the outer groove portion is broken. Thereby, the fastening force can be determined by the breaking strength of the thin portion.

Further, since the taper portion is formed in the outer groove portion, the fractured portion of the shear nut is further fastened in a state of riding on the outer side in the radial direction of the taper portion, the taper portion is pressed inward in the radial direction, and the female screw portion is formed. By sandwiching the male screw part that is screwed with, the fixing strength is increased. Further, since the inner groove portion has a rectangular groove shape in cross section, the blade portion of the tool does not have an acute angle, the tool life is long, and the cutting waste can be easily discharged to facilitate the manufacturing.

Further, since the fracture surface when the thin portion between the outer groove portion and the inner groove portion is fractured is formed to be inclined in the same direction as the taper portion, the shear nut is immediately outwardly fractured to the outside in the radial direction of the taper portion. It will be riding up and the fixing will be done securely.

It is also possible to form the width across flats of the shear nut to be larger than the diagonal distance of the torque nut. With such a configuration, the tool adapted to the width across flats of the shear nut cannot be engaged with the torque nut, so that only the shear nut can be held and rotated.

It is also possible to form the width across flats of the shear nut smaller than the width across flats of the torque nut. With such a configuration, the tool adapted to the width across flats of the shear nut does not engage with the torque nut, so that only the shear nut can be held and rotated.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a side sectional view of a shear torque nut according to an embodiment of the present invention. In the present specification, the direction along the axis of the shear torque nut will be referred to as the axial direction, the direction in which the shear torque nut is tightened will be referred to as the inner side in the axial direction, and the direction for loosening will be described as the outer side in the axial direction. Further, the direction orthogonal to the axial direction will be described as the radial direction.

The shear torque nut 1 is a torque nut 2
And a shear nut 3 arranged axially outside of the torque nut 2, and female screw portions 4 and 5 of the same size formed radially inside of the torque nut and the shear nuts 2 and 3, respectively. . An inner groove portion 6 is formed over the entire circumference between the female screw portions 4 and 5, and an outer groove portion 7 is formed on the outer portion between the torque nut and the shear nuts 2 and 3.
Are formed all around.

The width across flats of the shear nut 3 is smaller than the width across flats of the torque nut 2. At the time of fastening, only the shear nut 3 is sandwiched by a tool such as a spanner and fastened.
The inner groove portion 6 has a width in the axial direction that is at least twice the pitch of the female screw portions 4 and 5, and an inner diameter d that is equal to or larger than the diameter d ′ of the troughs of the female screw portions 4 and 5 over the entire circumference. Has been formed.

The outer groove portion 7 is the entire outer circumference of the torque nut and the shear nuts 2, 3 in the radial direction, and is the inner groove portion 6.
It is arranged axially inward. A taper portion 8 is formed on the groove bottom surface of the outer groove portion 7 so as to gradually reduce in diameter toward the shear nut 3 arranged on the outer side in the axial direction.

The angle θ of the tapered portion 8 with respect to the axial direction is set to, for example, 30 degrees. The corner portion 9 on the inner side in the axial direction of the inner groove portion 6 is formed at a position overlapping the virtual tapered surface 10 when the tapered portion 8 is extended outward in the axial direction. The fastening torque of the torque nut 2 is configured to be determined by the distance L between the end portion 11 of the taper portion 8 on the axially outer side and the corner portion 9. The distance L is set long when the tightening torque is made strong, and set short when the tightening torque is made weak. In addition,
The distance between the end portion 11 and the female screw portion 4 is set to be longer than the distance L. With this configuration, the shear torque nut 1 is reliably broken along the virtual taper surface 10.

Next, the operation when the shear torque nut 1 is used will be described. FIG. 2A is a partially enlarged cross-sectional view of the inner groove portion and the outer groove portion of the shear torque nut in an initial state,
(B) is a partial enlarged sectional view of the same inner groove portion and outer groove portion immediately after fracture, and (C) is a partially enlarged sectional view of the same inner groove portion and outer groove portion after fastening.

First, the width of a tool such as a wrench is adjusted to the width across flats of the shear nut 3 and engaged with the width, and the bolt (not shown) is screwed from the torque nut 2 side and rotated. Since the width across flats of the torque nut 2 is smaller than the width across flats of the shear nut 3, the torque nut and the shear nuts 2 and 3 are never engaged at the same time. As shown in FIG. 2B, when the axially inner end 12 (see FIG. 1) of the torque nut 2 comes into contact with the object to be fastened and the shear nut 3 is further rotated, the torque nut 2 Only the shear nut 3 rotates in the state where is stopped. Then, the shear torque nut 1 is fractured along the virtual taper surface 10 connecting the end portion 11 of the outer groove portion 7 and the corner portion 9 of the inner groove portion 6, and the torque nut and the shear nuts 2 and 3 are separated. The torque when the shear torque nut 1 breaks can be adjusted by the distance L between the end 11 and the corner 9.

As shown in FIG. 2 (C), the shear nut 3
When is further rotated, the breaking portion of the shear nut 3 moves inward in the axial direction and rides on the taper portion 8 of the torque nut 2. Then, the axially outer end portion of the female screw portion 4 of the torque nut 2 is pressed inward in the radial direction, the bolt is sandwiched by the torque nut 2, and the bolt is firmly fixed to prevent loosening.

The width across flats of the shear nut can be formed larger than the diagonal distance of the torque nut.
A tool such as a spanner with a sham nut idles after the sher nut is sheared and separated, but since the torque nut is not rotated with the squeeze nut sandwiched, the torque nut can be accurately fastened with a predetermined torque.

[0022]

The present invention has the following effects. (1) Since the taper portion is formed in the outer groove portion, the shernut is further tightened in a state where the fracture portion of the shear nut rides on the outer side in the radial direction of the taper portion, the taper portion is pressed inward in the radial direction, and is screwed by the female screw portion. The mating male screw part is sandwiched and firmly fixed, and it is possible to reliably prevent loosening. (2) Since the inner groove portion has a rectangular groove shape in cross section, the blade portion of the tool does not have an acute angle, the tool life is long, and the chips can be easily discharged to facilitate the manufacturing. (3) Since the fracture surface when the thin portion between the outer groove portion and the inner groove portion is broken is formed to be inclined in the same direction as the taper portion, the shear nut should be mounted on the outer side of the taper portion in the radial direction immediately after the fracture. Therefore, the fixing is surely performed. (4) If the width across flats of the shear nut is formed larger than the diagonal distance of the torque nut, a tool such as a wrench or a wrench will hold only the two opposite faces of the shear nut and will not contact the torque nut. The torque nut can be prevented from being applied with a torque equal to or higher than a predetermined torque, and the torque nut can be fastened with a constant torque. (5) When the width across flats of the shear nut is formed smaller than the width across flats of the torque nut, a tool adapted to the width across flats of the shear nut cannot be engaged with the torque nut, so that only the shear nut is held and rotated. be able to.

[Brief description of drawings]

FIG. 1 is a side sectional view of a shear torque nut of the present invention.

2A is a partially enlarged cross-sectional view of an inner groove portion and an outer groove portion of a shear torque nut in an initial state, FIG. 2B is a partially enlarged cross-sectional view of the inner groove portion and outer groove portion immediately after fracture,
FIG. 6C is a partially enlarged cross-sectional view of the inner groove portion and the outer groove portion after being fastened.

FIG. 3 is a partially enlarged sectional view of a double nut according to a conventional example in an initial state, and FIG. 3B is a partially enlarged sectional view of the same double nut after fracture.

[Explanation of symbols]

1 Shear torque nut 2 Torque nut 3 Shernut 4,5 Female thread 6 inner groove 7 Outer groove 8 Tapered part 9 corners 10 Virtual taper surface 11 Edge 12 end

Claims (3)

(57) [Claims] 1. A torque nut and a shear nut each having a female screw portion of the same size formed radially inwardly, and a torque nut and a shear nut formed between the female screw portions of the torque nut and the shear nut, respectively, and having a width in the axial direction. An inner groove having a rectangular groove-shaped cross section having an inner diameter not less than twice the pitch of the female screw portion and a diameter not less than the diameter of the valley of the female screw portion; and the inner groove portion that is radially outside the torque nut and the shear nut. And an outer groove portion formed on the inner side in the axial direction, and a taper portion gradually decreasing in diameter toward the shear nut arranged on the outer side in the axial direction is formed on the groove bottom surface of the outer groove portion, and the inner groove portion is formed. The inner corners of the
Position that overlaps with virtual taper surface when extended outward in the direction
Shear torque nut characterized by being formed on. 2. The shear torque nut according to claim 1, wherein a width across flats of the shear nut is formed larger than a diagonal distance of the torque nut. 3. The shear torque nut according to claim 1, wherein a width across flats of the shear nut is smaller than a width across flats of the torque nut.