JP4194585B2 - Locking nut - Google Patents

Description

  The present invention relates to a nut that is screwed into a bolt to fasten an object, and more particularly to a locking nut that can prevent the screw from loosening.

  Conventionally, fixing means for tightening and fixing an object with a bolt having a male screw and a nut screwed to the bolt are known, and are widely used in various applications and fields. The bolt and the nut are tightened by screwing the male screw and the female screw. However, the tightening may be loosened by vibration, rotation or impact applied to the bolt or nut. Loose screws can destabilize the object and can cause serious accidents. Therefore, various methods and structures have been proposed in the past in order to prevent the screws from loosening.

  As for the screw, the bolt and nut are displaced in the opposite axial direction due to the stress from the tightening part, the screw groove disappears, and the thread of the female screw and female screw contact in the axial direction to hold and fix the tightening force. The state can be maintained. In order to prevent the screw from loosening, the screw and the female screw are prevented from returning in the axial direction, such as a lock nut or a spring washer. However, in the conventional screw return prevention means such as the lock nut and the spring washer, the male screw and the female screw are just shifted in the axial direction so that the thread is in close contact with the return prevention means. On the opposite side of the contact side, the gap between the external thread and female thread is large, and the screw groove is not lost. Yes, it was not possible to sufficiently prevent the screws from loosening.

  Therefore, a part of the nut that is deformed and brought into contact with the bolt to eliminate the screw groove to prevent the screw from returning is disclosed in Japanese Utility Model Laid-Open Nos. 55-115422 and 10-61645. It is disclosed in the gazette. The device disclosed in Japanese Utility Model Laid-Open No. 55-115422 is composed of a double nut of a lock nut and a tightening nut, and a tightening cylinder body having a tapered outer peripheral surface is integrally connected to the lock nut. A plurality of slits are inserted in the taper, and the tapered surface is deformed by pressing the tapered surface with a tightening nut. The invention disclosed in Japanese Patent Laid-Open No. 10-61645 is disclosed between the seat surfaces of the nut. A deforming protrusion is formed integrally with the nut, and the protrusion is inserted into a screw groove in the nut and the bolt and deformed to prevent loosening of the nut.

  However, in such a structure in which a part of the nut is deformed, the fastening cylinder and the base of the protrusion are integrated with the nut. However, there is a problem that a sufficient locking effect cannot be expected. Further, it is extremely difficult to release the fixing by the deformed tightening cylinder or the protrusion, and there is a possibility that a special jig is required. Furthermore, when the fixing is performed for a long time, it may not be possible to release the fixing. In particular, the formation of protrusions is a structure that is difficult to manufacture in a mass production method such as a forging method and is not suitable for manufacturing nuts that are mass-produced articles.

Japanese Utility Model Publication No. 55-115422 JP-A-10-61645

  The present invention is intended to provide a locking nut having a structure that can more reliably and firmly achieve the locking between the bolt and the nut and is suitable for mass production.

The present invention consists tightening nut (2) and the ring-shaped member (3), one slit traversing in the axial direction (2d) is formed from one end of the clamping nut (2) Waso to the other end, In the locking nut, the slit (2d) is narrowed by fitting the ring-shaped member (3) to the clamping nut (2), and the biting into the bolt is strengthened . The nut (2) has a tapered tube portion (2b) that extends in the axial direction while gradually decreasing in diameter from the lower surface of the nut portion (2a) , and is formed between the tapered tube portion (2b) and the nut portion (2a). in a direction parallel to the axial cylindrical portion (2e) is interposed, said ring-like member (3) is cylindrical with the same diameter slightly from one end to have a small diameter inner diameter to the other end than the outer diameter of the cylindrical portion (2e) When the ring-shaped member is attached to the bolt and the tightening nut (2) is screwed into the bolt, the inner surface of the ring-shaped member (3) and the tightening nut (2) Of the ring-shaped member (3) to the cylindrical portion (2e) of the tightening nut (2) . By the fitting , the reduced diameter state of the tightening nut is maintained , the biting is maintained, and the loosening prevention is achieved .

The ring-shaped member has a step portion bent toward the bolt.

A female screw that is screwed into the bolt is formed on the inner peripheral surface of the stepped portion.

The inner peripheral surface of the step portion is formed in a cylindrical surface.

According to the locking nut of the present invention, a tightening nut having a part of the outer peripheral surface as a tapered surface and longitudinally cut in the axial direction by a slit is reduced in diameter by a ring-shaped member that comes into contact with the tapered surface. Since the peripheral surface is brought into contact with the outer peripheral surface of the bolt and the female screw and the female screw are brought into contact with each other so that the screw groove disappears in both the axial and radial directions, an extremely stable loosening prevention effect is achieved. Can be achieved. Further, since the ring-shaped member maintains the reduced diameter state of the tightening nut, there is no possibility that the screw will return. Furthermore, the presence of the cylindrical portion following the tapered surface, since the fitting state between the ring-shaped member and the tightening nut is held in the cylindrical portion, as long as the fastening nut remains within the range of the cylindrical portion, the nut tightening Even if is moved, the biting of the tightening nut into the bolt is maintained, and the biting does not fluctuate, so that loosening of the bolt by the nut can be avoided.

  A preferred embodiment of the present invention will be described in detail below. A locking nut according to the present invention includes a tightening nut formed with a tapered surface in a part of an outer peripheral surface and vertically divided by a slit vertically cut from one end to the other end in an axial direction, and a taper surface of the tightening nut, And a ring-shaped member that collaborates to reduce the diameter of the tightening nut. The inner diameter surface of the tightening nut is brought into close contact with the bolt by the diameter reduction, so that the screw groove disappears, preventing the screw from returning and preventing loosening. It is characterized by being able to do it. The slit has a predetermined width that can bring a required diameter reduction to the nut, and the tightening nut is reduced in diameter within the range of the slit width and is in close contact with the outer peripheral surface of the bolt.

  The tapered surface formed on the outer peripheral surface of the tightening nut has an outer diameter that can reduce the diameter of the nut so that the inner peripheral surface of the nut closely contacts the bolt in cooperation with the ring-shaped member at least at a predetermined outer diameter position. It is characterized by being. In addition, a cylindrical surface portion extending in parallel with the axial direction is provided at the maximum outer diameter position that brings about the tight contact state, and the reduced diameter state of the nut can be stably maintained by cooperation with the ring-shaped member in the cylindrical surface portion. And The tapered surface may be structured to extend to the maximum outer diameter surface of the nut, but this may cause the axial length of the nut to become too large. Therefore, it is preferable to form the taper surface from the maximum diameter portion to a plane orthogonal to the axial direction so that the entire length is shortened. Further, instead of the plane orthogonal to the axial direction, a slope having a large inclination angle may be continuously formed on the outer peripheral surface of the nut from the maximum diameter portion or the end of the cylindrical surface portion parallel to the axial direction. . By making such a slope with a large inclination angle continuous, it becomes easy to produce a tightening nut by a forging method, and a nut structure suitable for mass production can be obtained.

  The ring-shaped member for reducing the diameter of the tightening nut in cooperation with the tapered surface of the tightening nut is a cylindrical body having a length equal to or greater than the axial length of at least the tapered surface portion of the tightening nut, The inner diameter is set to a diameter capable of reducing the diameter of the tightening nut in cooperation with the taper surface so as to be in close contact with the bolt. The outer diameter is preferably equal to the outer diameter of the tightening nut, but is not limited thereto. The inner diameter portion of the ring-shaped member is preferably formed with a step portion approximately equal to the outer diameter of the bolt, and a female screw that is screwed to the bolt is formed on the inner peripheral surface of the step portion as necessary. It is not necessary to form. When forming the stepped portion, the length of the cylindrical portion to the stepped portion is at least equal to or longer than the axial length of the tapered surface portion. Thereby, the tip of the taper surface portion of the tightening nut can be abutted against the stepped portion, and a stronger tightening can be achieved by the reaction force from the ring-shaped member. When forming a female thread at the step of the ring-shaped member, the outer diameter of the ring-shaped member is the same as the tightening nut and the same hexagonal nut shape for tightening with the same size spanner. Is preferable.

  1 to 12, (1) is a bolt, which has a desired length capable of fixing a plurality of objects as is conventionally known, and has a hexagonal head (1a) at one end. Are integrally formed, and the tightening nut (2) can be screwed from the other end. If the bolt is a built-in bolt, the head (1a) is not necessarily required. (3) is a ring-shaped member, and (4) is a washer. As shown in FIG. 2, after a desired object (5) is inserted into the bolt (1), a ring-shaped member (3) is screwed with a washer (4) interposed therebetween, and a tightening nut (2) is further inserted. Screw in and tighten. As the tightening nut (2) is fitted into the ring-shaped member (3), the taper tube portion (2b) having a tapered surface that gradually increases in diameter is brought into contact with the ring-shaped member (3) to tighten. The diameter of the nut (2) is reduced and the nut (2) is brought into close contact with the outer peripheral surface of the bolt (1), and the thread groove of the male screw and the female screw is eliminated. The inner peripheral surface of the tightening nut (2) Is in close contact. Thereby, since the loosening of the screw is prevented, a stable loosening prevention effect can be expected.

  As shown in FIG. 1 and FIGS. 3 to 8, the tightening nut (2) includes a hexagonal nut portion (2 a) and a tapered tube portion having a tapered outer peripheral surface (continuous to the nut portion (2 a)). 2b) are connected together. A female screw (2c) is formed continuously on the nut part (2a) and the tapered tube part (2b), and a slit (2d) is formed in the axial direction of the nut, and the nut is continuous from one end to the other end in the axial direction. And the diameter can be reduced by the width of the slit (2d). Therefore, when the ring-shaped member (3) is fitted to the outer peripheral surface of the tapered cylindrical portion (2b), the tightening nut (2) is pressed and reduced in diameter along the inclination of the tapered surface, and the outer peripheral surface of the bolt. It comes in close contact with. The axial length of the tapered tube portion (2b) is equal to or larger than the length to the step portion of the ring-shaped tube portion (3) described later, and the tip of the tapered tube portion (2b) is the ring-shaped tube portion (3 It is preferable that the two are integrated in the axial direction.

  14 and 15 show one modification of the tapered cylindrical portion (2b), in which a cylindrical portion (2e) parallel to the axial direction is formed continuously to the maximum tapered portion. When the ring-shaped member (3) is fitted to the cylindrical portion (2e), the reduced diameter state of the tightening nut (2) is maintained, and the loosening prevention effect is further stabilized. 16 and 17 show still another modification, which is continuous with the inclined surface (2f) from the cylindrical portion (2e) to the nut portion (2a) continuously to the cylindrical portion (2e). The formation of the inclined surface (2f) makes it easy to manufacture the tightening nut (2) by a forging method, resulting in a structure suitable for mass production. As shown in FIGS. 1, 2, 14, and 15, when the tapered cylindrical portion (2 b) or the cylindrical portion (2 e) and the nut portion (2 a) are continuous on a right angle surface, manufacturing by forging is difficult. In addition, since it is necessary to manufacture by a casting method or a cutting method, it is not suitable for mass production, and there is a risk of increasing costs. Needless to say, the slope (2f) may be formed continuously with the tapered tube portion (2b) shown in FIGS.

  As shown in FIGS. 9 to 13, the ring-shaped member (3) that comes into contact with the tapered tube portion (2 b) of the tightening nut (2) and reduces the diameter of the tightening nut (2) preferably has an outer peripheral surface. Hexagonal nut shape (3d), consisting of a cylindrical portion (3a) having an inner diameter that abuts against and presses against the tapered cylindrical portion (2b), and a step portion (3b) formed at one end thereof. On the inner peripheral surface of 3b), a female screw (3c) that is screwed into the bolt (1) is formed. The axial length of the cylindrical portion (3a) is equal to or slightly shorter than the length of the tapered portion (2b) of the tightening nut.

  FIGS. 18 and 19 show a modification of the ring-shaped member (3), in which a female thread is not formed on the inner peripheral surface of the stepped portion (3b) but is formed in a cylindrical shape. 20 and 21 show still another modification of the ring-shaped member (3), in which the step portion (3b) is not formed and the inner diameter is the same from one end to the other end in the axial direction. In short, the ring-shaped member (3) is fitted into the taper surface of the tapered tube portion (2b) as the tightening nut (2) is screwed into the bolt (1) and advances. The shape and structure are not particularly limited as long as it has a cylindrical portion that can be reduced in diameter.

  As shown in FIGS. 2, 18, and 20, when the ring-shaped member (3) is first inserted into the bolt (1) and the tightening nut (2) is screwed into the bolt (1) and screwed, the taper The tapered surface of the cylindrical part (2b) is fitted into the ring-shaped member (3) and gradually reduced in diameter, and when tightening is completed, the tightening nut (2) is brought into close contact with the bolt (1) and the screw and female screw The screw groove in between disappears. The screw groove between the male screw and the female screw disappears in both the axial direction and the radial direction, and the male screw and the female screw are in close contact with each other, so that an extremely strong locking effect can be achieved. I can do it. In addition, the ring-shaped member is fitted to the cylindrical surface that is continuous with the tapered surface, so that the reduced diameter state is strong, and it can be prevented from loosening even if it receives an impact, etc., compared to when it is located on the tapered surface. The risk of being eliminated is reduced.

Exploded perspective view of the locking nut and bolt of the present invention Longitudinal section showing the fixed state Top view of tightening nut FIG. 3A-A ′ line longitudinal sectional view Tightening nut front view Side view Bottom view Rear view Plan view of ring-shaped member FIG. 9B is a longitudinal sectional view taken along line B-B ′ Front view of ring-shaped member Side view Bottom view Longitudinal sectional view showing the fixed state by one deformation of the tightening nut Perspective view of a clamping nut for the same deformation Longitudinal sectional view showing a fixed state by further deformation of the tightening nut A perspective view of a tightening nut according to another modification Longitudinal sectional view showing a fixed state by one deformation of a ring-shaped member The perspective view of the ring-shaped member concerning the same deformation Longitudinal sectional view showing a fixed state of the ring-shaped member due to another deformation The perspective view of the ring-shaped member concerning another deformation | transformation

Explanation of symbols

(1) Bolt
(1a) Head
(2) Tightening nut
(2a) Nut
(2b) Tapered tube
(2c) Female thread
(2d) Slit
(2e) Cylindrical part
(2f) Slope
(3) Ring-shaped member
(3a) Tube part
(3b) Step
(3c) Female thread
(3d) Nut shape
(4) Washer
(5) Object

Claims (4)

It becomes tightening nut (2) and a ring-shaped member (3), one slit traversing axially from one end of the nut (2) Waso tightening to the other end (2d) is formed, a nut fastening ( In the locking nut, the slit (2d) is narrowed by fitting the ring-shaped member (3) to 2) and the biting into the bolt is strengthened. Is formed with a tapered cylindrical portion (2b) extending in the axial direction while gradually decreasing in diameter from the lower surface of the nut portion (2a), and between the tapered cylindrical portion (2b) and the nut portion (2a), parallel cylindrical portion (2e) is interposed, said ring-like member (3) is provided with a cylindrical portion having the same diameter from one end to the other end to slightly have a smaller diameter inner diameter than the outer diameter of the cylindrical portion (2e), When the ring-shaped member is attached to the bolt and the tightening nut (2) is screwed into the bolt, the inner surface of the ring-shaped member (3) and the taper of the tightening nut (2) The nut (2) comes into contact with the cylindrical part (2b), the tightening nut (2) is bitten into the bolt while being reduced in diameter, and the ring-shaped member (3) is fitted to the cylindrical part (2e) of the tightening nut (2). According to the present invention , the diameter of the tightening nut is maintained , the bite is maintained, and the locking is achieved . The locking nut according to claim 1, wherein the ring-shaped member has a step portion bent toward the bolt. 3. The locking nut according to claim 2, wherein a female screw that is screwed into the bolt is formed on the inner peripheral surface of the stepped portion. The loosening prevention nut according to claim 2, wherein the inner peripheral surface of the step portion is formed in a cylindrical surface.

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