JPS6326410A - Lock nut - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lock nut having a locking structure.

[Prior Art] Various torque-increasing lock nuts have been proposed in the past. For example, a ring-shaped elastic member made of nylon or the like having an inner diameter smaller than the diameter of this female thread is sympathetically and fixedly disposed on the female thread of a nut body made of metal, and the nut body is attached to a threaded part such as a bolt. When the member is screwed into the male thread, the inner peripheral surface of the ring-shaped elastic member comes into elastic contact with the male thread and is deformed, resulting in I? ! m force is generated and this 1
? Lock nuts are known that have a locking effect due to clearance. However, in such a lock nut, only the ring-shaped elastic member makes elastic contact with the male thread, so the contact friction force generated between the male thread and the ring-shaped elastic member is relatively small and sufficient. The loosening prevention effect is very low.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned points, and its purpose is to solve the problem between the female thread of a nut and the male thread of a threaded member such as a bolt. Relatively large F! To provide a lock nut that can generate friction force and can have a reliable locking effect.

[Means for solving the problem] According to the present invention, the object has a first female thread that is screwed into the male thread, and an inner diameter smaller than the inner diameter of the first female thread. This is achieved by a lock nut made of a synthetic resin material and having a second internal thread circumferentially provided on a portion of the internal thread of the cylinder 1.

[Specific Examples] Preferred specific examples of the present invention will be described below based on the drawings.

In FIGS. 1, 2, and 3, reference numeral 1 indicates a lock nut made of a synthetic resin material according to the present invention. The outer periphery 3 of the lock nut 1 is composed of six surfaces, and a chamfered portion 4 is formed at the boundary between the outer periphery 3 and the upper surface 2 of the lock nut 1. The chamfered portion 4 is preferably the upper surface 2
The chamfer angle α1 is set to 309. The lock nut 1 is provided with a female U portion 6 circumferentially about the central axis 5. The female threaded portion 6 is composed of a female thread 7 having a first inner diameter d1 and a female thread 8 having a second inner diameter d2, and the female threads 7 and 8 each have a common root diameter d3. ing. The female thread 7 has a length f in the direction along the central axis 5.
The internal threads 8 are formed at multiple locations on the female threaded portion 6 over a rotation angle α3 with respect to the central axis 5, and over a length 11 in the direction along the central axis 5 and over a rotation angle α4 with respect to the central axis 5. It is located between the female threads 7 on the female thread portion 6. Therefore, the female thread 7 and the female thread 8 each have the same pitch, and differ only in their respective inner diameters. Preferably, the rotation angle α3 of the female thread 7 and the female thread 8 is set to 90°, and the rotation angle α4 is set to 30”. Also, the length 11 of the female thread 7
The rotation angle α3 may be appropriately set depending on the required frictional force.

A chamfered portion 9 with a diameter d5 and a chamfer angle α2 is provided at the opening on the upper surface 2 side of the female U portion 6, and a chamfered portion 9 with a diameter d4 and a chamfer angle α5 is provided on the opening on the seat surface 10 side of the lock nut 1. Chamfered portions 11 are provided respectively. The chamfer angles α2 and α5 are preferably set to 120°, respectively. Further, a chamfered portion 12 is formed at the boundary between the seat surface 10 and the outer peripheral portion 3. The chamfered portion 12 preferably has a chamfer angle α6 of 30° with respect to the seat surface 10.

The seat surface 10 side of the female threaded portion 6 has the same inner diameter d2 and root diameter d as the female thread 8 to facilitate screwing into the male thread.
A guide portion 13 is provided in which a female thread 14 having a diameter of 3 is provided over a length I3 in a direction along the central axis 5.

In the boundary portion 15 between the guide portion 13 and the female thread portion 6, an angle of the surface of each female thread, that is, a guide angle αγ is provided. The guide angle α7 is preferably set to 12o°.

The lock nut 1 according to the present invention is made of a synthetic resin material, preferably a plastic material or a nylon material.

The lock nut 1 configured in this way is called the lock nut 1.
When screwing into a male thread of a bolt or the like having the same effective diameter as that of the female thread 8, the female thread 14 of the guide part 13 is first easily screwed into the thread, and then the female thread 8 and the female thread 7 are rotated. The internal threads 6 are arranged alternately in the angular direction and are screwed into the internal threads 6, but since the internal diameter d1 of the internal threads 7 is smaller than the internal diameter d2 of the internal threads 8, the internal diameter tips of the internal threads 7 strongly interfere with the root diameter of the external threads. This causes a strong frictional force between the male thread and the female thread 1. Further, due to the strong interference force between the female thread 7 and the male thread, the entire lock nut 1 made of plastic material can be elastically deformed, and the deformation stress also causes a gap between the female thread 7 and the male thread. An even larger interference force is added to the female thread 7.
In addition, due to the elastic deformation of the entire lock nut 1, the female threads 8 and 14 are also deformed, and as a result, these female threads are screwed together. Since it is strongly pressed against the external thread, it can create a new locking effect even in areas where it would not normally have a locking effect. Therefore, a very large loosening prevention effect can be obtained as a whole.

[Effects of the Invention] Since the lock nut according to the present invention has the above-described configuration, when screwed into the male thread, the lock nut has a diameter larger than that of the male thread. In addition to the frictional force due to the interference force generated between the two female threads, the deformation stress of the entire lock nut causes damage not only between the male thread and the second female thread, but also between the male thread and the first female thread. It is possible to prevent new frictional force from being generated between the two, and a great loosening prevention effect can be reliably produced.

In addition, since the lock nut according to the present invention is made of a synthetic resin material, it has excellent elasticity, and even nuts with a small effective diameter can be easily manufactured in one piece.
High corrosion resistance, a
A lock nut with chemical resistance can be easily obtained, and in addition, the weight of the nut body can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a lock nut according to the present invention, FIG. 2 is a cross-sectional view of the lock nut according to the present invention taken along line If-If in FIG. 1, and FIG. 3 is a bottom view of the lock nut according to the present invention. 1...Lock nut, 5...Center shaft,
6...Female thread part, 10... Seat surface, 13
...Information department. Figure 2 Figure 3

Claims (4)

[Claims] (1) A first female thread that is screwed into the male thread; A lock nut made of synthetic resin material with two internal threads. (2) The lock nut according to claim 1, wherein the second female thread is provided at a plurality of locations on the inner circumferential surface of the first female thread in the rotation angle direction. (3) Claim 1 or 2, wherein the female threads occupy 90° on the inner circumferential surface of the first female thread with respect to the rotation angle direction and are arranged at equal intervals. Lock nut. (4) The lock nut according to any one of claims 1 to 3, wherein the synthetic resin material is plastic.