JPH08121455A - Nut with loosening locking and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide a nut with loosening locking formed so as to obtain by a constitution at a low cost both loosening locking of the nut and supporting performance against axial force and to provide a suited method of manufacturing this nut with loosening locking. CONSTITUTION: A nut with locking 10 is constituted by providing a nut main unit part 11 having a normal screw part 14a with a regular screw size and pitch and an extension part 12 having a deformed screw part 14b with a screw size and pitch respectively smaller than the screw size and pitch of the normal screw part 14a. By the constitution thus obtained, axial force applied to the nut 10 is surely supported by screwing in a proper condition the normal screw part 14a of the nut main unit part 11 to a screw part of a bolt, and loosening the nut 10 is prevented by locally increasing a contact pressure between the deformed screw part 14b and the screw part of the bolt in the deformed screw part 14b of the extension part 12, so that as a result, axial force supporting performance as a nut essential function and reliability of tightening condition by locking of the nut can be both easily obtained without using a separate member or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a locking nut and a manufacturing method thereof.

[0002]

2. Description of the Related Art Generally, when a plurality of members are fastened by using bolts and nuts, it is necessary to prevent the nuts from loosening to maintain a stable fastened state. As a measure for preventing the loosening of the nut, for example, a method of attaching a dedicated member for preventing loosening to the nut, or an actual flat blade 1
As disclosed in Japanese Patent Publication No. 135220, a slit is formed in a radial direction of a nut, and when the nut is screwed into a bolt, the nut is deformed in the bending direction from the slit portion to reduce the diameter of the screw hole. There is known a method of locally increasing the contact pressure between the thread surface of the thread groove of the bolt and the thread surface of the thread groove of the nut in the reduced diameter portion to stop the loosening of the nut.

[0003]

However, of the above-mentioned conventional methods, the former method requires a separate dedicated member to prevent the nuts from loosening, which makes the work complicated and increases the cost. There is a problem of being invited.

In the latter method, since the slit is formed in the nut, a great number of man-hours are required for processing the nut, which causes an increase in cost. Also, when the nut is bent and deformed at the slit portion, the screw hole of the nut is tilted in a substantially tapered shape, so that the contact state of these two screw surfaces is not a perfect surface contact but a one-sided contact state. There is also a problem that the support performance for force is reduced.

Therefore, the present invention has been made as a proposal for a nut with a lock and a suitable manufacturing method thereof, which makes it possible to achieve both the lock of the nut and the support performance against the axial force by an inexpensive structure.

[0006]

In the present invention, the following constitution is adopted as a concrete means for solving such a problem.

According to a first aspect of the present invention, there is provided a lock nut having a nut body having a normal thread portion having a regular screw diameter and a pitch, and a nut body coaxially arranged on one end side in the axial direction of the nut body portion. It is characterized in that it is provided with an extending portion which is extended and has a deformed screw portion having a screw diameter and a pitch smaller than the screw diameter and the pitch of the normal screw portion.

A method of manufacturing a nut with lock according to a second aspect of the present invention comprises a large diameter nut main body portion and a small diameter extension portion coaxially extending on one end side of the nut main body portion. Further, a nut member formed by forming a screw hole having a regular screw diameter and pitch by penetrating the shaft center portion of the nut main body portion and the extended portion is used, and the nut member is axially pressed to It is characterized in that the extended portion is compressed and deformed, and the screw diameter and the pitch of the portion of the screw hole corresponding to the extended portion are each made smaller than the normal size.

According to a third aspect of the present invention, there is provided a method for manufacturing a nut with locking device, which is the same as the method for producing the nut with locking device according to the second aspect, wherein the nut member is an anti-extension part of the nut body. A projection nut having a welding projection on its side end surface, and the projection nut and the nut fixing member are axially connected by a pair of flat electrodes in a state where the welding projection of the projection nut is in contact with the nut fixing member. It is characterized in that projection welding is performed by applying a voltage while pressurizing in the direction, and the extended portion is axially compressed and deformed by the pressing force and welding heat during the welding.

[0010]

According to the present invention, the following actions and effects can be obtained by adopting such a configuration.

According to the lock nut according to the first aspect of the present invention, the nut body having the normal thread portion having the regular screw diameter and pitch, and the thread diameter and the pitch of the normal thread portion respectively. The axial force applied to the nut is such that the normal screw part of the nut body is properly screwed into the screw part of the bolt because it is configured with an extension part having a deformed screw part with a small screw diameter and pitch. When the nut is loosened, the contact pressure between the deformed screw part and the screw part of the bolt is locally increased in the deformed screw part of the extension part by loosening. It will be prevented. Therefore, according to the nut with lock of the present invention, it is possible to easily achieve both the axial force supporting performance as the original function of the nut and the reliability of the tightened state by the lock of the nut without using a separate member or the like. Is something that can be done.

According to the second aspect of the present invention, there is provided a lock nut having a lock structure, which comprises a large-diameter nut body portion and a small-diameter extension portion, and which penetrates the shaft center portions of the nut body to form a regular screw. With respect to a nut member formed with a screw hole having a diameter and a pitch, the nut member is pressed in the axial direction to compressively deform the extended portion, and a portion of the screw hole corresponding to the extended portion is By reducing the screw diameter and the pitch respectively from the normal dimensions, it is possible to obtain a nut with lock preventing member having two types of screw parts having different screw diameters and pitches. In comparison with a method of forming a slit by cutting the above, the manufacturing is easier and the cost can be reduced accordingly.

According to the method for manufacturing a lock nut according to a third aspect of the present application, in the method for manufacturing a nut with lock stopper according to the second aspect, the nut member is a projection nut, and the projection nut is By applying a voltage while applying pressure in the axial direction by a pair of flat electrodes to perform projection welding, the extension portion is axially compressed and deformed by the welding pressure and welding heat at the time of welding, whereby the screw diameter and Since the lock nut with two types of screw parts with different pitches is obtained, in addition to the same effects as described above, the lock nut can be processed simultaneously in the welding process of the projection nut. As a result, the work man-hours can be reduced compared to the case where the loosening prevention process is performed in a separate process. You can expect downdown.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The nut with lock and the method for manufacturing the same according to the present invention will be described below in detail with reference to the accompanying drawings.

1 and 2 show a nut member 1 used as a projection welding nut.
The nut member 1 includes a nut body 11 having a hexagonal nut shape.
And a small-diameter thin-walled cylindrical extending portion 12 continuously formed at one end of the nut body 11 in the axial direction, and the nut body 11 and the extending portion 12 have an axial center portion between them. A threaded hole 14 of a predetermined standard is provided so as to cross over, and the end portion of the nut body 11 on the side opposite to the extending portion 12 is formed by ridges having a predetermined height at equal intervals in the circumferential direction. Protrusion 1
3, 13, 13 are provided.

As shown in FIG. 2, the nut member 1 abuts against the lower surface side of the nut fixing member 2 with the welding projection 13 abutting against a predetermined position of the plate-like nut fixing member 2. The lower plane electrode 3 arranged and the upper plane electrode 4 abuttingly arranged on the upper surface side of the extending portion 12 are pressed by the pair of upper and lower projection welding electrodes in the axial direction, and the pair of electrodes. By applying a predetermined welding voltage between 3 and 4, as shown in FIG.
13 is locally melted and welded and fixed to the nut fixing member 2.

In this embodiment, the nut member 1 itself fixed to the nut fixing member 2 by projection welding is provided with a locking mechanism, which is used as the locking nut 10. That is, as described above, the nut member 1 is attached to the pair of upper and lower electrodes 3,
When projection welding is performed by applying a predetermined welding voltage while sandwiching and pressing the nut 4, the nut member 1 is heated by welding heat and a predetermined pressing force is applied in the axial direction. In this case, the entire nut member 1 is heated by the welding heat, but between the nut body 11 and the extension portion 12, the extension portion 12 is thinner than the nut body portion 11 and its heat capacity is Because it is small, the nut body 11
The temperature of the extended portion 12 is larger than that of the extended portion 12, and therefore the degree of softening due to heat is larger. On the other hand, with respect to the pressing force of the pair of electrodes 3 and 4, the extension portion 1 is more extended than the nut body portion 11.
2 is the load transmission direction (that is, the axial direction of the nut member 1)
The cross-sectional area in the plane orthogonal to is small, and the load applied per unit area increases accordingly.

Due to these synergistic effects, the nut member 1 is made by the pair of electrodes 3 and 4 during projection welding.
When a predetermined pressing force is applied in the axial direction to the extension portion, as shown in FIG. 3, the nut body portion 11 is hardly deformed, and the extension portion has a large degree of softening and a large load load per unit area. 12 is positively compressed and deformed, and both the inner diameter dimension and the axial length dimension are reduced. As a result, of the screw holes 14 of the nut member 1, the portion corresponding to the nut body 11 is the normal screw portion 14a having the initial standard, but the portion corresponding to the extended portion 12 is more than the original standard. Is also a deformed screw portion 14b having a reduced screw diameter and a reduced screw pitch. Therefore, when a bolt (not shown) having a screw of a standard corresponding to the screw hole 14 is screwed into the screw hole 14, the above-mentioned deformation occurs. The threaded portion 14b is strongly engaged with the thread of the bolt, so that the deformed threaded portion 14b
The surface pressure between the threaded surface of b and the threaded surface of the bolt locally increases, and the self-locking state appears due to the frictional force acting between them, so that the nut member 1 is prevented from loosening from the bolt. It is done. That is, the nut member 1 is a nut 10 with a locking mechanism having a locking mechanism by performing projection welding.

As described above, the extended portion 1 of the screw hole 14 is
Only the part corresponding to 2 has a diameter smaller than the screw hole of the specified standard.
The deformed threaded portion 14b has a reduced pitch, and the portion corresponding to the nut body 11 is the normal threaded portion 14a according to the standard. The locking nut 10 can be securely prevented from loosening, and at the same time, the normal screw portion 14a can reliably support the axial force applied in the bolt axial direction. That is, it is possible to achieve both the support performance of the bolt axial force and the loosening prevention of the nut with a simple structure.

When the nut member 1 is formed of a projection nut as in this embodiment, the loosening prevention process is performed at the same time when the nut member 1 is fixed by welding. For example, the loosening prevention process is a separate process. Processing work is simpler than that in the case described above, and the cost can be reduced by reducing the man-hours.

In the above embodiment, the extended portion 1
2 is formed in a thin-walled cylindrical shape, but the present invention is not limited to this. For example, the extended portion 12 is formed in a thin-walled tapered cylindrical shape as shown by a chain line in FIG. 1 (see reference numeral 12 '). It can also be formed.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing a manufacturing process of a locking nut according to an embodiment of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a state change diagram of FIG.

[Explanation of symbols]

1 is a nut member, 2 is a nut fixing member, 3 is a lower plane electrode, 4 is an upper plane electrode, 10 is a nut with a locking member, 1
1 is a nut body part, 12 is an extension part, 13 is a protrusion for welding,
Reference numeral 14 is a screw hole, 14a is a normal screw portion 1, 14b is a deformed screw portion, and 15 is a welded portion.

Claims (3)

[Claims] 1. A nut main body having a normal screw portion having a regular screw diameter and a pitch, and a screw diameter of the normal screw portion which is coaxially extended to one end side in the axial direction of the nut main body portion. And a nut with a lock for preventing loosening, comprising: an extending portion having a deformed screw portion having a screw diameter and a pitch each smaller than the pitch. 2. A nut main body having a large diameter and a small diameter extending portion coaxially extending on one end side of the nut main body, and a shaft center portion between the nut main body and the extending portion. A nut member is formed through which a screw hole having a regular screw diameter and pitch is formed. The nut member is pressed in the axial direction to compressively deform the extended portion, and the extended portion of the screw hole is extended. A method for manufacturing a nut with locking device, characterized in that a screw diameter and a pitch of a portion corresponding to the installation portion are each made smaller than a regular dimension. 3. The nut member according to claim 2,
A projection nut having a welding projection on the end surface of the nut main body on the side opposite to the extending portion, and fixing the projection nut and the nut in a state where the welding projection of the projection nut is in contact with a nut fixing member. The projection welding is performed by applying a voltage while pressurizing the member and the member in the axial direction with a pair of flat electrodes, and the extended portion is axially compressed and deformed by the welding pressure and welding heat. And a method for manufacturing a nut with a lock.