JP2018044558A - Looseness inhibition thread - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a looseness inhibition thread for inhibiting looseness of a fastened thread caused by vibration.SOLUTION: A part of a pan chamfering part 8 of a female thread 5 of a male thread 1 and the female thread 5 concentrically fitted to each other is formed with a convex part 7. This convex part 7 is placed on an orbit through which a top part 4 of a crest of the male thread and has a position and a size in which the top part 4 of the crest of the male thread slides against it. During fastening operation, the top part 4 of the male thread fastens the convex part 7 of the female thread 5 under an inclined state while slightly scratching it. Upon becoming the fastened state, a bearing surface 3 of the female thread 5 compresses against a fastened member 11 and the convex part 7 of the female thread 5 strongly compresses the top part 4 of the crest of the male thread to restrict its looseness.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a loosening suppression screw that suppresses loosening under vibration.

  Conventionally, a screw is loosened due to factors such as vibration even if a member to be fastened is tightened. In order to prevent this loosening, hexagon bolts with nylon inserts or pre-ringing torque type detent nuts made of all metal hex nuts were used.

  In addition, Patent Literature 1 discloses a fastening bolt and a screw fastening body using the fastening bolt. Patent Document 2 discloses a structure for preventing loosening of a screw in which a thread root portion of a nut is inclined. Patent Document 3 discloses a thread of a fastening member in which the thread pressure side flank angle is inclined toward the male screw head and the flank surface is formed on a curved surface.

JP 2012-72837 A JP 2008-208983 A JP 2008-144955 A

  However, conventionally, the flank angle of the male screw and the female screw is generally about 30 ° with respect to the axis in the reference angle. When vibration occurs in the male screw and the female screw, one of them is inclined in an oblique direction, and the contact surface between the head of the male screw and the member to be fastened, or the contact surface between the seat surface of the female screw and the member to be fastened is uniform. Since no pressure is applied, the frictional force is reduced and loosening occurs. Moreover, in the inclination of the valley bottom part of patent document 2 with the inclination | tilt angle of 27 degree | times-37 degree | times, since an axis line inclines, the locking effect cannot be expected. When the flank angle of the thread pressure side flank is formed on a curved surface like the external thread of Patent Document 3, the male screw and the female screw become a wasteful curved surface, and there are difficulties in manufacturing technology and manufacturing cost. is there. Therefore, an object underlying the present invention is to provide a loosening prevention screw that has a simple shape and is inexpensive to manufacture and can be tightened by a simple operation.

  Therefore, in the present invention, the means of the present invention taken in order to solve the above problems are as follows. In the first means, in the male screw and the female screw that are concentrically fitted with each other, a convex portion is formed on the track through which the top of the male screw thread passes in the vicinity of the counter chamfered portion of the upper part of the female screw. . The convex portion is formed at a position where it is in contact with the top of the male screw thread, and when the male screw and the female screw are tightened, the convex portion has a size and a position where it is in close contact with the top of the male screw thread. A loosening prevention screw characterized by having

According to this, while the female screw is screwed into the male screw, there is a gap between the two flank so that the wobble is wobbled. The convex portion is formed in the axial direction on a part of the counter chamfer of the female screw on the wobbled and inclined side. Further, the distance measured in the direction perpendicular to the axis of the convex portion is such that when the male screw is fitted to the female screw and the axis of the female screw being screwed is inclined, It is a distance to pass each other. The convex portion has an elongated shape in a direction along a trajectory of the top of the male screw. That is, the convex portion is provided on the chamfered chamfer, and is on a trajectory through which the top of the male screw thread passes, and further, the convex portion and the top of the male screw thread are positioned at a distance. In addition, it is desirable that the top of the male screw thread be in close contact with the line, not a point.

In the second means, the convex portion of the female screw is a loosening prevention screw according to the first means characterized in that the seat surface direction is inclined from the top surface side toward the outer peripheral side.

According to this, in the state where the female screw fitted to the male screw is tilted, the top of the male screw and the surface of the convex portion rub against each other in parallel. In addition, the inclination angle of the surface of the convex portion is the same as the inclination angle of the female screw, so that the rubbing contact surface is enlarged to increase the frictional force.

When the male screw is screwed in, the crest of the male screw comes to be tightened while lightly rubbing the convex portion of the female screw. In this state, the male screw advances the screwing while being inclined obliquely with respect to the female screw. At this time, the axis of the female screw is inclined with respect to the axis of the male screw. In the tightened state, the seat surface of the female screw is pressed against the member to be fastened, and the axis of the male screw and the axis of the female screw become parallel. At this time, the crest of the male screw is strongly pressed against the axis by the convex portion of the female screw. By this pressure contact, loosening is suppressed.

Conventionally, if there is a relative inclination or misalignment between shafts between a male screw and a nut to be screwed, it causes loosening. The convex portion of the female screw is one of the most affected portions of the fitting portion of the male screw and the female screw, and is one of the places where the influence can be suppressed most. If the looseness is suppressed at this position, it can be effectively suppressed with a small force. The top of the male screw thread and the convex portion of the female screw are pressed in a direction perpendicular to the axis so that they do not loosen even if vibration occurs.

  The loosening prevention screw of the present plan will be described as an example. As the member to be fastened is tightened with the male screw and the female screw, the light screw passes between the convex portion of the female screw and the top of the mountain of the male screw. Therefore, tightening can be advanced with bare hands. When the tightening is approaching and tightening with a tool such as a spanner, the pressure side flank of the male screw and the pressure side flank of the female screw come into contact with each other, and as the tightening is performed, the convex portion of the female screw and the peak of the male screw However, it comes to press-contact, contacting the axis line at a right angle. For this reason, even if vibration occurs, loosening is prevented by the male screw and the female screw.

  According to the present invention, the fastening member to be fastened by the male screw and the female screw can be screwed with a bare hand until the seating surface side of the female screw is pressed against the fastening member, and finally only by tightening with a tool such as a spanner. The top of the crest of the male screw is prevented from loosening due to vibration because the convex portion of the female screw prevents the screwing rotation. Also, when manufacturing, it can be made at low cost by technically simple work.

It is a schematic sectional drawing of the state which tightened the slack prevention screw concerning the present invention. It is a schematic sectional drawing in tightening of the loosening prevention screw which concerns on this invention. It is a top view of the slack prevention screw concerning the present invention. It is sectional drawing of the AA line of the loosening prevention screw which concerns on this invention.

The embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic cross-sectional view of a state in which the male screw 1 and the female screw 5 according to the embodiment of the present invention are tightened. The top 4 and the convex part 7 of the female screw 5 are in a state of being strongly pressed. When the fastened member 11 is tightened with the male screw 1 and the female screw 5, the pressure-side flank 2 of the male screw and the pressure-side flank 6 of the female screw come into contact with each other, and at the same time, the fastened member 11 and the seat surface 3 of the female screw 5 are brought into contact with each other. It shows a state in which the crest 4 of the male screw 5 and the convex portion 7 of the female screw 5 are in close contact and strongly pressed. The convex portion 7 is provided on the countersink chamfer 8 on the inclined side when the axis of the female screw 5 is inclined with respect to the axis of the male screw 1, and the direction of the seating surface 3 from the top surface 9 is It is inclined to the outer peripheral side and has the same inclination angle as the inclination of the female screw 5. Further, it is sized to be rubbed lightly on the top 4 of the male thread. When tightening, it is screwed while tilting diagonally. When the screwing is about to end, the seat surface 3 side of the female screw 1 presses the member to be fastened 11 and the axes try to be parallel to each other obliquely. At the end of screwing, the axes are parallel to each other. The seating surface 3 tends to be in close contact with the fastened member 11 when the axes are about to become parallel to each other as tightened. Since the convex portion 7 strongly presses the crest 4 of the male screw toward the axial line side, it suppresses loosening. When the male screw 1 and the female screw 5 are fitted to each other, the distance between the surface of the countersink chamfer 8 and the top 4 of the male screw thread is the distance of the convex portion 7, and more specifically, the axes of the male screw 1 and the female screw 5 are It is a distance that passes lightly when inclined, and a distance that rubs strongly when the axes are parallel to each other.

FIG. 2 shows a cross-sectional view of the male screw 1 and the female screw 5 that are in the process of being fastened together. When the male screw 1 and the female screw 5 are tightened, the convex portion 7 of the female screw 5 has a size for rubbing the crest 4 of the male screw 1 while the male screw 1 is inclined. Further, it is provided along the surface of the dish chamfer 8. Further, when the inclination of the male screw 1 is small, the return of the inclination is small and the locking effect is small. For this reason, it is desirable to use a shape in which the clearance between the flank of the opposing male screw 1 and the flank of the slack suppressing screw is increased to increase the inclination.

FIG. 3 shows a plan view. The convex portion 7 is provided in a part of the chamfer chamfer 8 on a track through which the top 4 of the male screw thread passes. The convex portion 7 is provided at a position where the top 4 of the male screw thread rubs. 4 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 4, a part of the countersink chamfer 8 is provided with a length of one-sixth of the female screw 5 and a width that can be accommodated in the countersink chamfer 8 at a position where the crest 4 of the male thread passes. It is desirable to form the elongated protrusion 7. The convex portion 7 is screwed so as to be rubbed while being in contact with the top 4 of the male screw being inclined. The convex portion 7 of the female screw 5 strongly presses the crest 4 of the male screw toward the axis. It is desirable that the seat surface 3 of the female screw 5 is formed with a seat surface 3 with the same perpendicular direction as the convex portion 7 as viewed from the axial line side. Thus, when tightened, the convex portion 7 of the female screw 5 comes into strong pressure contact with the crest 4 of the male screw, thereby increasing the prevention of loosening.

When the loosening prevention screw according to the present invention is used, the loosening prevention can be obtained only by tightening the fastened member 11 with the male screw 1 and the female screw 5.

Further, the present invention is not limited to the above-described embodiments and examples, and the male screw 1 and the female screw 5 are iron, stainless steel, etc. Is possible.

1 Male thread 2 Male thread pressure side flank 3 Bearing surface 4 Male thread crest 5 Female thread 6 Female thread pressure side flank 7 Convex part
8 dish chamfering
9 Top surface 11 Fastened member
13 Valley bottom

Claims (2)

In the male screw and the female screw that are concentrically fitted to each other, a convex portion is formed on the track through which the top of the male screw thread passes in the vicinity of the counter chamfered portion of the upper portion of the female screw. The convex portion is formed at a position where it meets the peak of the male screw, and when the male screw and the female screw are tightened, the convex portion has a size and a position where it is in close contact with the top of the male screw. A loosening prevention screw characterized by having. The loosening prevention screw according to claim 1, wherein the convex portion has a shape in which a seating surface direction is inclined from the top surface side toward the outer peripheral side.