JP2023158747A - Fastener - Google Patents

Abstract

To provide a fastener having no risk of collapsing threads, easily and properly bringing about a fastening state, and excellent in a loosening prevention function.SOLUTION: A fastener comprises a bolt 10, an auxiliary member 20 and a nut body 30. In the bolt, a groove-shaped recess 104 which is recessively formed along an axial direction is formed on a male screw part of a bolt shaft. The auxiliary member is formed into a substantially-cylindrical shape having an insertion hole h1 inserted with the bolt shaft, and has a flange 201 at one end of an opening part of the insertion hole. A protrusive part 204 fit to the groove-shaped recess is formed at an inner wall face. In the nut body, a one-way rotation mechanism is fit and fixed to an accommodation part in a housing 301 in which a female screw screwed to the male screw of the bolt shaft is formed at a bottom part, and a sidewall of the auxiliary member contacts with the one-way rotation mechanism.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fastener with excellent loosening prevention function.

Generally, when fastened members are tightened and fixed using bolts and nuts, the axial force (tensile force) generated in the shaft of the bolt and the compressive force (tightening force) generated in the fastened members are integrated. When the two are balanced, the connected state is maintained.

However, simply screwing a bolt and nut together and tightening them will result in initial loosening due to roughness of the contact part of the screw fastener, and return rotation of the nut due to static or dynamic fluctuations in axial force, resulting in the tightening condition. Looseness occurs.

Therefore, various efforts have been made in the past. For example, grooved hexagonal nuts, nylon nuts, nuts utilizing a wedge-locking effect, and locking nuts incorporating friction rings are well-known.

Specifically, the technology is characterized in that a clutch piece having a columnar shape with a substantially elliptical cross-sectional shape that contacts the threaded portion of the bolt when the bolt is screwed together is disposed at a position that contacts the threaded portion of the bolt. It has been disclosed (see Patent Document 1).

Japanese Unexamined Patent Publication No. 58-156712 Japanese Patent Application Publication No. 11-117954

However, in the invention described in Patent Document 1, the tip of the clutch piece is crimped onto the male threaded part of the bolt and engaged, so the contact area between the clutch piece and the screw is insufficient, and the effect of preventing loosening and rotation is limited. be. Furthermore, there is a risk of crushing the screw thread.
Therefore, there has been a desire for further improvements that can produce an appropriate fastened state without crushing the threads and have an excellent loosening prevention function.

Therefore, as a result of intensive research to solve this problem, the inventor of the present application obtained a new idea and completed the present invention.

In order to solve the above problem, the invention according to claim 1 is a fastening tool for fastening members to be fastened, the fastening tool includes a bolt, an auxiliary member, and a nut body, and the bolt has a male part of the bolt shaft. A groove-like recess is formed on the threaded portion along the axial direction, and the auxiliary member has a substantially cylindrical shape with an insertion hole through which the bolt shaft is inserted, and one end of the opening of the insertion hole. The nut body has a flange on the inner wall thereof, a protrusion that fits into the groove-like recess, and the nut body is arranged in a housing having a female thread formed on the bottom part to be screwed into the male thread of the bolt shaft. A one-way rotation mechanism is fitted and fixed in the housing part, and a side wall of the auxiliary member is in contact with the one-way rotation mechanism.

Further, in the invention according to claim 2, in the configuration according to claim 1, the auxiliary member in which the protruding portion fits into the groove-like recess rotates with rotation of the bolt shaft, and the auxiliary member rotates as the bolt shaft rotates. The rotational torque in the forward direction is not transmitted to the one-way rotation mechanism and the auxiliary member rotates idly, and the rotational torque in the screw-back direction is transmitted to the one-way rotation mechanism via the auxiliary member, so that the rotation is Characterized by being blocked.

As described above, the present invention has a structure in which the convex part of the auxiliary member fits into the groove-like recess on the male threaded part of the bolt shaft and slides on the male threaded part as the bolt screws. Since the unidirectional rotation mechanism can be applied without crushing the threads of the male screw, an appropriate fastening state can be created regardless of the level of skill of the operator, and a high loosening prevention effect can be obtained.

FIG. 2 is a configuration diagram showing a bolt, an auxiliary member, and a nut body according to an embodiment of the present invention. (a) It is a sectional view taken along the line AA showing the structure of the auxiliary member according to one embodiment of the present invention. (b) It is a sectional view taken along the line BB showing the structure of the auxiliary member according to one embodiment of the present invention. FIG. 2 is an exploded perspective view of a nut body according to an embodiment of the present invention. FIG. 1 is a perspective partial sectional view showing the structure of a nut body according to an embodiment of the present invention. 1 is a partially sectional view showing a state in which a fastener according to an embodiment of the present invention is used. FIG. 3 is a sectional view taken along line CC showing the mechanism of the one-way rotation mechanism.

Embodiments of the present invention will be described below.
Note that the size, shape, and positional relationship of each part constituting the present invention are schematically described for the purpose of promoting understanding of the present invention. In addition, the materials of each component and the illustrated shapes and structures are disclosed as examples of suitable combinations, and do not preclude modifications that can achieve this effect without departing from the spirit of the present invention.

The present invention relates to a fastener used for fastening a member to be fastened to an object, which includes a bolt, an auxiliary member, and a nut body, and which connects the member to be fastened between the bolt head and the nut body housing the auxiliary member. and clamps and fastens the object. The details will be explained below.

The bolt 10 is formed by forming a groove-like recess 104 on a male threaded portion 103 of a bolt shaft 102, which is recessed along the axial direction over a predetermined length with a constant width and depth. (Figure 1, Figure 6)

The auxiliary member 20 has a substantially cylindrical shape with an insertion hole h1 through which the bolt shaft 102 is inserted, a flange 201 is formed at one end of the opening of the insertion hole h1, and a flange 201 is formed on the inner wall surface 203 in the groove-like recess 104. A fitting protrusion 204 is formed over a predetermined length with a constant width and height. (Figure 1, Figure 2, Figure 6)

The nut body 30 has a female thread 304 formed on a bottom part 303 to be screwed into the male threaded part 103 of the bolt shaft 102, and a one-way rotation mechanism P is fitted and fixed in a housing part 302 in the housing 301. (Figure 3, Figure 4)

The typical structure and principle of the one-way rotation mechanism P is, for example, as disclosed in the above-mentioned Patent Document 2, one of the two members concentrically combined with each other rotates in both directions. This is a mechanism used to transmit only the rotational movement in one direction to the other member when the member moves. This mechanism is also called a "one-way clutch", and specifically, for example, a "shell type roller clutch" sold by NSK Ltd. can be used.

The procedure for attaching the fixed object A to the target object B (here, the object refers to an object to which the fixed object A is fixed, such as a machine or a building) will be explained. It is assumed that a hole with a large outer diameter of the bolt shaft 102 is provided in advance in the fixed object A and the target object B.

The bolt shaft 102 is inserted into both holes of the object to be fixed A and the object B, and the auxiliary member 20 is inserted into the protruding bolt shaft 102 with the flange 201 facing the object B side. Subsequently, the auxiliary member 20 is inserted into the insertion hole h2 of the nut body 30, and the tip of the male threaded portion 103 is screwed into the female threaded portion 304 of the nut body 30. In this state, the side wall 202 of the auxiliary member 20 and the roller P1 are in contact with each other to the extent that a one-way rotation mechanism is activated. (Figure 5)

When the bolt 10 is rotated in the tightening direction, the protruding portion 203 fits into the groove-like recess 104, so the auxiliary member 20 rotates in the same direction as the bolt shaft 102 rotates, and the bolt shaft 102 is screwed. The entry progresses.

Although the side wall 202 of the auxiliary member 20 is in contact with the roller P1 of the one-way rotation mechanism P, the direction in which the bolt shaft is screwed in is opposite to the direction of rotation in which the mechanism acts, so the side wall 202 rotates together with the bolt shaft. The auxiliary member 20 rotates idly (that is, the mechanism does not work), and the screwing of the bolt shaft continues.
When the screwing of the bolt shaft is completed, the object A and the object B are held between the bolt head 101 and the flange 201 of the auxiliary member 20, and the fastened state is completed. (Figure 5)

The roller P1 of the one-way rotation mechanism P is in contact with the side wall 202 of the auxiliary member 20, and when rotating in one direction (FIG. 6(A)), the rotational torque is not transmitted to the roller P1, but in the other direction. During rotation (FIG. 6(B)), the rotational torque is transmitted.
That is, when the bolt 10 is screwed in, that is, rotated in the tightening direction (clockwise rotation), the rotational torque is not transmitted to the roller P1 and the auxiliary member 20 rotates idly, causing the male threaded portion 103 and the female threaded portion 304 to rotate. However, when an attempt is made to rotate the bolt 10 in the unscrewing or loosening direction (clockwise rotation), the rotational torque is transmitted to the roller P1, and the clutch mechanism is activated, causing the auxiliary member 20 and this The bolt 10 in the engaged state does not rotate to the left. (Figure 6)

After the fastening with the bolt 10 is completed and the bolt head, the fixed object A, the object B, and the nut body 30 are integrally fastened, the one-way rotation mechanism P must be destroyed in order to loosen it. The bolt 10 will not rotate to the left unless a force is applied that causes the bolt to rotate counterclockwise.
That is, the fastener 1 of the present invention does not loosen under normal usage conditions.

According to the present embodiment, the tightening work is easy, and a proper fastening state can be created, and a high loosening prevention effect can be obtained.

The present invention does not rely on strong tightening force to maintain the fastened state like conventional bolts and nuts, but has a structure that uses a one-way rotation mechanism to prevent loosening after a certain fastened state is achieved. Therefore, it is particularly effective, for example, when the fixed object A or the target object B is made of glass, brick, ceramics, porcelain, resin, or other materials that are fragile to physical forces.
It is also expected to be widely used in locations where periodic inspection is difficult once the tightening work has been completed.

1 Fastener 10 Bolt 101 Bolt head 102 Bolt shaft 103 Male threaded part 104 Groove-shaped recess 20 Auxiliary member 201 Flange 202 Side wall 203 Inner wall surface 204 Convex strip 30 Nut body 301 Housing 302 Accommodation part 303 Bottom part 304 Female threaded part
A Part to be fastened B Target object
h1 Insertion hole h2 Insertion hole
P One-way rotation mechanism P1 Roller

Claims (2)

A fastener for fastening members to be fastened,
The fastener includes a bolt, an auxiliary member, and a nut body,
The bolt has a groove-like recess formed along the axial direction on the male threaded portion of the bolt shaft,
The auxiliary member has a substantially cylindrical shape with an insertion hole through which the bolt shaft is inserted, has a flange at one end of the opening of the insertion hole, and has a protruding strip on an inner wall surface that fits into the groove-like recess. form,
The nut body has a one-way rotation mechanism fitted and fixed in a housing part in the housing, which has a female thread formed at the bottom to be screwed into the male thread of the bolt shaft,
A fastener in which a side wall of the auxiliary member is in contact with the one-way rotation mechanism. The auxiliary member, in which the protruding portion fits into the groove-like recess, rotates with the rotation of the bolt shaft, and the rotational torque in the spiral direction is not transmitted to the one-way rotation mechanism and is rotated by the auxiliary member. 2. The fastener according to claim 1, wherein the fastener rotates idly, and rotational torque in the screwing-back direction is transmitted to the one-way rotation mechanism via the auxiliary member, thereby preventing the rotation.

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