JPH01182614A - Locking nut - Google Patents

Abstract

PURPOSE:To make the locking function of a nut perfect by combining a nut having a circumferential part formed to have a globular surface along the external angle part of the bearing surface and a washer having a receiving part fitting to said globular surface in the upper internal angle part. CONSTITUTION:A nut 2 is in contact with a clamped body 6 through a washer 4, with the bearing surface 3 of the nut 2 and the receiving part of the washer forming part of a complementarily irregular globular surface. Even if the clamped body 6 is not necessarily disposed horizontally to the vertical axis of the bolt 1, the angle varies by the self movement of the washer 4 so as to correspond to this situation, and thus the pressure distribution on the bearing surface 3 of the nut 2 is made uniform in the circumferential direction. Further, as the pressure applied to the nut 2 is added slanting outward to the washer 4, the pressure is uniformly distributed on the whole bearing surface of the washer 4, and the bearing surface pressure is symmetrized to reduce the return rotating action of the nut 2.

Description

[Detailed Description of the Invention] The biggest drawback of screws is that they loosen after they are installed, and various methods have been devised since ancient times to prevent this, but each of them has its advantages and disadvantages, and is not completely perfect. The current situation is that there is nothing.

By the way, loosening of screws includes (1) Non-rotating loosening Loosening that does not occur due to the return rotation of the nut, which is caused by the settling of irregularities such as on the bicep surface. (2) Loosening due to rotation: Loosening due to rotation of the nut due to external force such as vibration.

In the case of (1), the progress can be prevented by stopping at a certain point or by re-tightening, but in the case of (2), this is difficult to prevent and requires other parts or adhesives. Many people have used methods that take time and effort, but there is still no perfect solution.

Therefore, we have thought of countermeasures against screws, assuming that screws naturally loosen, but with the opposite idea, one of the major causes of loosening is that screws are made so that they do not loosen. It is necessary to pay attention to making the surface pressure uniform.

Any vibrations applied to the nut will eventually result in horizontal sliding motion of the seat surface, but if the pressure distribution on the seat surface is not uniform at this time, frictional resistance will be concentrated in the area of maximum pressure. It is. However, the nut has a donut-shaped seat surface because the bolt needs to pass through the center, so if one part is strongly pressurized, the pressure on that target side will be less, and the left and right sides will be affected. It is natural that it will be uneven. After the bolt and nut are fastened, the force acting to loosen them is the force applied from all directions, up and down, left and right, due to vibrations, thermal expansion, etc., but only the force in the direction that tries to rotate the nut. If we investigate further, we can think of only the horizontal movement that occurs between the tightened body and the nut's seating surface, so we can only consider the state of the nut's seating surface and the contact surface with the tightened body in this case. When you look at it, the seat surface of the nut slides back and forth on the horizontal plane while being pressurized by the object to be tightened.

Therefore, at this time, if there is uneven pressure on the seat surface on the left and right sides,
For example, if we consider a case where a larger load is applied to the left side of the front and back, the frictional resistance on the left side of this part is greater than the right side, so when the seat is pushed forward, if the thread is a right-hand thread, If the screw tries to move in the direction of tightening, and on the other hand is moved back, the screw will be moved in the direction of loosening. By the way, a screw essentially has a large resistance when moving in the tightening direction and a small resistance when moving in the loosening direction, so even if the seat is moved back and forth the same distance, the screw will move in the loosening direction each time. This will cause the screw to loosen.

Normally, when a screw is tightened, the male and female threads are crimped together, and the frictional force generated between them resists the force in the direction of loosening the screw, so if a properly made screw is used correctly,
It's not something that will come loose.

However, (a) the tightening surface is sagging, caved in, and (b) galling. (c) Gaps between clamped plates due to waving, warping, curling, etc.

(d) Dripping of paint during painting, uneven peeling of the paint film.

(Po), quick entry into gaps between objects.

etc., the stress of the tightening torque applied to the bearing surface will be applied unevenly to the threaded surface of the bolt and the bearing surface of the nut, so the average left and right frictional resistance of the bearing surface, that is, the stress of the tightening torque applied to the bearing surface will be This causes an imbalance in the force exerted by the nut, causing the nut to loosen and rotate.

Fastening with screws uses a helical screw, so there is essentially no left-right imbalance, and the seat surface of the nut should originally be perpendicular to the axis, but it is unavoidable due to design reasons.
The screw holes may be drilled at a slight angle or may have a slight inclination due to machining accuracy, which, in addition to the above-mentioned problems with the tightening conditions, is a major cause of loosening.

By the way, elastic washers are generally used to prevent screws from loosening, but this is used to prevent shock from being transmitted to the screws, and it does not have the power to correct the average pressure on the left and right sides, and also prevents bubbling. As for nuts, we cannot expect anything more than the effect of preventing loosening and rotation by expanding the seat surface outward.

The present invention is a new proposal for equalizing the seat pressure, which is a major cause of such nut loosening, and thereby attempts to perfect the locking function of the nut.

To explain this with reference to the drawings, the nut (2) is formed so that the outer corner of its seat surface (3) becomes a part of a spherical surface, and the washer (4) is formed on the inner peripheral surface of the upper surface of the nut (2). ) is angled to match the seat surface of the seat (5).
) The present invention has such a structure, so the nut (2) screwed onto the bolt (1) has a washer (4
), but the bearing surface (3) of the nut (2) and the receiving part (5) of the washer (4)
) forms a part of a spherical surface with complementary concavities and convexities, so even if the tightened body (6) is not necessarily installed horizontally with respect to the vertical axis of the bolt (1), the washer (4) ) The angle changes due to the automatic movement of the nut (°2), and the pressure distribution applied to the seat surface (3) of the nut (°2) becomes completely uniform in the circumferential direction.

Furthermore, since the pressure applied to the nut (2) is applied diagonally outward with respect to the washer (4), it is distributed evenly over the entire bearing surface of the washer (4), and the bearing surface pressure is made symmetrical. This exerts a great force in reducing the return rotation effect of the nut (2).

Since the present invention has such a very simple structure, it is a strong lock nut that can be manufactured at low cost regardless of size, can be used repeatedly without causing mistakes, and can be used many times without damaging the threads. Regardless of the target, it is possible to apply a uniform load to the seat surface and each screw thread even if the object to be tightened has some difficulty such as unevenness or slope, and its simplicity makes it suitable for tightening with automatic assembly machines. Because of its unique elasticity, it can withstand relative movement between parts, stiffness, vibration, loosening of screws due to thermal changes, etc. without losing its anti-rotation effect, without using additional parts such as spring washers or double nuts.

Furthermore, this invention can be applied not only to nuts, but also to bolts and small screws, and by simply applying this idea to the heads of bolts and screws, it is possible to create products with a great anti-rotation effect.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the invention. 1: Bolt 2: Nut

Claims (1)

[Claims] A locking nut that combines a nut with a peripheral part with a spherical surface along the outer corner of the seat, and a washer with a receiving part similar to the spherical surface at the inner corner of the upper surface.