JPH01303308A - Locknut - Google Patents

Abstract

PURPOSE:To provide a locknut itself with highly safe fastening force by forming a projection projecting toward one side on a periphery of a screw hole of the locknut, and also forming a female thread effective for fastening by at least two piths on the screw hole. CONSTITUTION:In a locknut 1, a projection 7 projecting toward one side 3 is formed on a periphery of a screw hole 5. A female thread effective for fastening is formed at least by two piths on the screw hole 5, while a space hole 6 is formed on the remaining other side 4. After the screwing and fastening of the rocknut 1 to a bolt 15, a nut 2 is fastened. Loosening prevention effect is improved accordingly, by fastening the nut over the rocknut, and thereby providing the rocknut itself with highly safe fastening force.

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to bolt tightening, and more specifically, when tightening with a double nut, it can be tightened more firmly and properly, and safety such as fatigue can be reduced. Concerning the lock nut that has been improved.

(b) Prior Art Conventionally, bolts and nuts have been defined by JIS standards. The male and female threads are graded based on thread accuracy. The finer the thread is, the higher the precision mentioned above, the more difficult it is to achieve smooth threading between the male and female threads. Sao JIS
According to the standard, it is approximately 60% to 80% of the nominal diameter of the screw.
This is caused by the fact that the friction force of the screw is also large in proportion to the contact length, and therefore the planting torque is larger than the tightening axial force.

On the other hand, looking at the manufacturing methods for nuts, there are two methods: cutting,
Some are made by forging. Generally, unless it is a special nut, it is mass-produced, and at least its external shape is manufactured by forging. And forging, regardless of cold or hot processing,
Because they can be plastically deformed and the metal structure is made more dense, forged nuts are said to have better strength than nuts made by cutting. However, when forging, unlike the process of carving a thread on the outer periphery of a round bar like a bolt, when a thread is carved in the hole of a nut, it is difficult to process it by rolling like a male thread. Often, therefore,
Generally, the female thread is finished by cutting at the final processing stage of the nut.

A conventional example will be explained with reference to FIG. 3. In this example, a nut is double-tightened to prevent loosening in a vibrating machine such as a press. That is, align the hole (not shown) of the machine leg 17 with the bolt 15 embedded upright on the floor G, place it on the floor G, and screw the lock nut 1'' onto the bolt. , Tightening is done later by screwing together the nut 2. 16 is a washer. This double nut is almost always used for installation when the machine is subject to fogging. , are also often used in mechanical connections.The lock nut 1' and nut 2 are used together because the screws have an allowable tolerance and there is a gap between the male and female threads. After tightening lock nut 1', tighten nut 2.
It is said that by tightening the screws, the male and female screws press against each other and prevent the male and female screws from slipping, thereby preventing them from loosening.

(c) Problems to be Solved by the Invention However, as far as the bolt 15 mentioned above is concerned, since the lock nut 1 is tightened and the nut 2 is further tightened the lock nut 1', the load is applied to the upper nut 2. On the bolt 15 side, it is thought that stress concentration occurs in the valley of the male thread on the lower surface (leg portion 17 side) of the lock nut 1'. Further, in machines such as presses that repeatedly undergo shocking vibrations, the thickness of the bolt 15 is determined with a high safety factor. For such devices, it is important to prevent screws from loosening from the standpoint of safety.

In addition to double nuts, there are other ways to prevent screws from loosening, such as using a split bottle or bottle to fasten the nut to the bolt.
Machine screws are also used to prevent loosening, but there are many places where these methods cannot be used.

Therefore, an object of the present invention is to make it easier to screw together a lock nut, and to tighten the nut from above, thereby imparting a highly safe fastening force to the lock nut itself, thereby increasing the locking effect. It is.

(d) Means for Solving the Problems The present invention has been made in view of the above-mentioned circumstances. For example, as shown in FIGS. 1 and 3, two nuts (
1) and (2), tighten one lock nut (1) to the bolt (15), then tighten the other nut (2).
The lock nut (1) is provided with a protrusion (7) around the screw hole (5) that protrudes toward the labor and management (3); The screw hole (5) is characterized in that it has at least two pitches of female thread effective for tightening, and the remaining part is an escape hole (6) on the other side (4).

(E) Function Based on the above configuration, when used in the same way as a normal lock nut (1), the escape hole (6) makes it easy to align the hole with the bolt (15), and the screw hole (5) There is no screwing out with a small pitch, so screwing is smooth.

Then, screw the lock nut (1) onto the bolt (15) and tighten it later, and then tighten the nut (2>).
2) The bottom surface is a lock nut (1) - labor and management (top surface) (3)
As it comes into contact with the screw hole (5), it presses the protrusion (7) provided around the screw hole (5), and the excess thickness of the protrusion (7) moves into the screw hole (5), causing it to plastically deform. and bolt (
15) The gap is filled in such a way that the gap is fluidly changed to the allowable tolerance with respect to the male screw, and the female screw and the male screw are locked.

Note that the above-mentioned symbols in parentheses do not limit equivalent configurations.

(f) Example Embodiments of the present invention will be described below along with the drawings.

In addition, in the following examples, the third
The explanation will be made using figures, and the same reference numerals and names will be used for the same parts.

First, a first embodiment will be described with reference to FIG. 1. A lock nut 1 has a hexagonal outer shape, and a projection 7 protruding outward is provided on the upper surface (one side) 3 around five screw holes. The protrusion 7
The height of is made to protrude from the top surface 3 by half the pitch of the female thread,
Its outer diameter is approximately the same as the root diameter of the screw.

And, the thread length of the female thread with the male thread is 15 bolts.
When screwed together, there are at least two and a half pitches, and the remaining lower surface (the other side) 4 is provided with an escape hole 6 whose diameter is slightly larger than the root diameter of the screw. 8 is a chamfered portion.

Since the screwing length of the screw hole 5 is at least two and a half pitches, the screwing can be done smoothly and lightly, and since the relief six 6 makes it easy to insert the bolt 15, the screwing can be done smoothly. Since the threads are engaged with two or more pitches, the lock nut 1 can be screwed into the bolt 15 at right angles. Also, in the manufacturing method, since the escape hole 6 has a larger diameter than the pilot hole (not shown) of the screw hole 5, the outer shape and pilot hole can be easily finished by forging based on the escape hole 6. . The relief six 6 can be used as a guide hole from the beginning of forging to the end of thread machining, and the forging process can be automated.

Next, a second embodiment will be explained with reference to FIG. 2. This lock nut 1 is characterized in that a flange 9 is provided on the lower surface 4 side. That is, the upper surface 3 is provided with a protrusion 7 that protrudes around the screw hole 5, and a recess 66 is formed in the remaining portion of the lower surface 4 from the screw hole 5, as in the first embodiment.

In the case of this second embodiment, when the lower surface 4 is the same size as a conventional hexagonal nut, the contact area of the lock nut 1 with the seat surface is reduced, so a flange 9 is provided to prevent the seat surface from sinking. This is a means to prevent the occurrence of loosening.

(G) As described in detail, according to the present invention, a protrusion is provided on one side, so that when the lock nut is tightened later, the protrusion moves in the direction of the screw hole of the lock nut. It is deformed and embedded so that it flows into the gap due to the allowable tolerance between the female thread and the male thread, so the connection between the female thread of the lock nut and the male thread of the bolt in question is made firm, and when the upper nut is further tightened until it adheres to the lock nut, the above-mentioned Of the protrusions, completely embed in the female thread side of the lock nut,
The excess meat that could not flow presses the screw hole of the upper nut, and similarly fills the screw hole of the nut and becomes locked. However, when tightening a nut, you can control the tightening torque and make sure that the tightening is sufficient by tightening the nut until you can no longer see the protrusion on the lock nut, and then tightening it until the top surface of the lock nut and the bottom surface of the nut are in contact. It can be easily confirmed visually. When the embedding and tightening are completed, the locking connection is solid even though it is a threaded connection of at least 62 pitches, so no loosening will occur.In addition, by providing an escape hole, it can be done at low cost.
It can be made into a nut that can be mass-produced, and because of the relief six, it is useful for shortening the length of the male thread of the bolt.
By configuring the relief hole, the starting point of engagement with the bolt on the underside of the lock nut changes upward, so the load distribution also shifts upward, thereby preventing a decrease in the fatigue limit of the bolt, and similarly Since the stress concentration on the valley of the male screw is also alleviated, it is effective in preventing the nut from loosening, and is also greatly useful in improving the strength of the bolt.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing the main parts of the first embodiment of the present invention;
FIG. 2 is a side view of a second embodiment of the present invention;
FIG. 3 is a side view of a conventional example with a foundation bolt. 1... Lock nut 2... Nut 3...
Top surface (one side) 4...Bottom surface (other side) 5...Screw hole 6...Escape hole 7...Protrusion Patent applicant Tsukiboshi Seisakusho Co., Ltd.

Claims (1)

[Claims] (1) In a lock nut that uses two nuts, one lock nut is tightened to a bolt, and then another nut is tightened to firmly fix the bolt to the bolt and prevent it from loosening. A lock nut, characterized in that a protrusion protruding on one side is provided around the screw hole, the screw hole has at least two pitches of female thread effective for tightening, and the remaining part is an escape hole on the other side.