JP5729697B1 - Locking screw - Google Patents

Abstract

The present invention provides a locking screw having a simple structure that reliably exhibits a nut locking function, has high workability, and is inexpensive. A fixed member is fixed by a male screw and a female screw. The thread 18 of at least one of the male screw 12 and the female screw 20 is formed in a wave shape along the winding of the screw, and the lead angle α changes periodically. The male screw 12 of the bolt 10 is formed in a wave shape, and is screwed with a normal nut 14 to fix the fixed member 16. The wavy screw thread 18 has a plurality of wave numbers, for example, 3 or 4 wave numbers in one rotation 360? Of the screw. [Selection] Figure 1

Description

  The present invention relates to a locking screw that prevents a screw member having a structure in which a male member and a female screw are screwed together to fasten and fix a fixed member.

  Conventionally, tightening with a double nut is generally used as a method for preventing a nut screwed into a bolt. However, the double nut is one in which the nuts are fixed by friction caused by the tightening force between the nuts, and it is weak against long-term durability and vibration.

  Thus, as a more reliable locking structure, a locking apparatus in which various devices are formed on the nut has been proposed. However, these locking apparatuses have a large number of parts and cost, and the structure of the fastening portion. There was a problem of increase in weight and space.

  On the other hand, there is a locking nut disclosed in Patent Document 1 as a locking nut having a relatively simple structure. This nut is a double nut with a pair of nuts, and the contact surface of each nut is contacted at an angle larger than the lead angle of the screw and bonded together. After tightening the double nut, the upper nut of the pair of nuts It is fixed by turning in the opposite direction. This fixing is performed by applying a force that presses the threads in the loosening direction by reverse rotation because the inclination of the contact surface is larger than the lead angle.

JP 2000-35025 A

  However, the loosening prevention structure using the double nut disclosed in Patent Document 1 is the same as the fixing using the frictional force of the normal double nut, and acts on the contact surface between the male screw and the female screw with a constant lead angle. It is fixed by the friction force generated there by the tightening force, and there is a risk of loosening due to long-term use or vibration.

  The present invention has been made in view of the background art described above, and has an object to provide a locking screw that has a simple configuration, reliably exhibits a nut locking function, has good workability, and is inexpensive. To do.

The present invention relates to a locking screw used for fixing a fixed member with a male screw and a female screw, wherein the thread of the male screw is formed in a wave shape along the winding of the screw, and the lead angle is periodic. The maximum change amount of the lead angle in the positive direction and the negative direction with respect to the average lead angle is substantially equal to the average lead angle with respect to the average lead angle of the male screw, and the male screw and the female Each screw thread of the male screw and the female screw is driven by the amplitude of the lead angle with respect to the helical winding of the wavy screw thread before the axial force due to tightening is applied. It is a loosening set screw that is displaced by causing displacement.

The present invention also provides a locking screw used for fixing a fixed member with a male screw and a female screw, wherein the thread of the female screw is formed in a wave shape along the winding of the screw, and the lead angle respect but periodically changes, the average lead angle of the female screw, the maximum amount of change in the plus and minus directions of the lead angle with respect to the average lead angle is approximately equal to the average lead angle, and the male screw Each of the male screw and the female screw is oscillated according to the amplitude of the lead angle with respect to the helical winding of the wavy thread before the axial force due to tightening is applied. A set screw that causes displacement of the thread and is screwed may be used.

  The wavy thread may be any one that has a plurality of integer wave numbers that can divide 360 degrees in one turn of the screw. Preferably, the wavy thread has a wave number of 3 to 8, more preferably 4 to 6, in one turn of the screw.

  The wavy thread is formed on at least one of a male thread and a female thread of a multi-threaded thread.

  According to the loosening prevention screw of the present invention, the screw loosening prevention function can be exhibited with a simple structure and without using special parts, etc., the manufacture is easy, and the cost is low.

It is a partially broken side view which shows the state which fixed the to-be-fixed member with the volt | bolt and nut of the locking screw of one Embodiment of this invention. It is an expanded view of the side surface of the external thread of the volt | bolt which is a locking screw of this embodiment. It is a schematic diagram explaining the lead | read | reed of the locking screw of this embodiment. It is a fragmentary sectional view which shows the screwing state of the volt | bolt and nut of the locking screw of this embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The locking screw of this embodiment is a male screw 12 of the bolt 10. As shown in FIG. 1, the bolt 10 is configured to sandwich and fix a member 16 to be fixed by a nut 14 and a head portion 11 of the bolt 10 in the same manner as a normal bolt.

  The male screw 12 advances by the lead L in the axial direction by one rotation of the bolt 10, and as shown in FIGS. 1 and 3A, a surface orthogonal to the axial direction of the male screw 12 of the bolt 10 having a diameter D. In contrast, the inclination angle of the coil 12a of the male screw 12 is the lead angle α. In the male screw 12 of this embodiment, as shown in FIGS. 1 and 3B, the screw thread 18 is formed in a wave shape in the axial direction at a constant period. Is formed by a sine curve or the like. The period of the wave of the screw thread 18 is 90 ° with respect to 360 ° of the circumference of the male screw 12, and the wave of the thread 18 is formed in four periods during one round of the circumference of the male screw 12. .

  As shown in FIG. 3B, the lead angle α (> 0) during one cycle of the wavy screw thread 18 is the maximum variation ± with respect to the average lead angle αave (> 0) of the male screw 12. This gives a change in the lead angle of β, and the value of the minimum lead angle αmin = αave−β is a value slightly on the minus side from 0 °, and the maximum lead angle αmax = αave + β of the wavy male screw 12 Is set to an angle that is slightly larger than twice the average lead angle αave. Therefore, it is preferable that the average lead angle αave≈maximum change amount β, more preferably αave≈β, and α <β.

  As shown in FIG. 2, when the fixed member 16 is fixed together with the nut 14 of the normal screw using the bolt 10 of this embodiment, the thread 22 of the normal female screw 20 of the nut 14 is corrugated of the male screw 12. The screw thread 18 shows a portion that is strongly pressed and deformed periodically during one round of 360 °. In this embodiment, since one wavelength of the wave of the screw thread 18 is 90 °, this pressure contact portion has four waves between the peripheral surface 360 ° of the portion where the male screw 12 and the female screw 20 are screwed together. Is formed. Accordingly, pressure contact portions are formed at eight locations in the direction opposite to the direction in which the screw travels. Thereby, the thread 22 of the female thread 20 of the nut 14 is deformed along the waveform of the thread 18 of the male thread 12 as shown in FIG.

  The thread 18 and 22 of each of the male screw 12 of the bolt 12 and the female screw 20 of the nut 14 has a lead angle of a wavy peripheral surface as shown in FIG. A strong pressing force acts from the thread 18 of the male screw 12 at the maximum portion and the portion where the lead angle is minimum as shown in FIG. The peaks 18 and 22 are displaced by Δa and are elastically deformed to be in pressure contact with each other. Further, as shown in FIG. 4 (b), the central thread 18 that is equal to the average lead angle αave of the lead angle α that changes in a wavy shape is in a contact state in the same manner as a normal screw. When a load is applied in the axial direction of the bolt 10 and the nut 14 by tightening, a force is applied to the male screw 12 thread 18 and the female screw 20 in the load direction and in the opposite direction, and the wavy lead angle is increased. The threads 18 and 22 are deformed in the load direction.

  The bolt 10 of the locking screw of this embodiment is formed so that the thread 18 of the male screw 12 is formed in a wave shape and the lead angle α is changed at a constant cycle, so that it is screwed with the nut 14. Then, the screw threads 18 and 22 are elastically deformed and pressed into contact with each other, and further, the nut 14 is tightened, so that the screw thread 22 of the female screw 20 of the nut 14 is pressed into contact with the female screw 20 at a portion having a large lead angle. The thread 22 is elastically deformed to prevent loosening. In addition, the nut 14 used here may be a normal screw nut, and it is not necessary to use a nut having a special structure, so that the cost can be reduced at a low cost.

  In addition, the locking screw of this invention is not limited to the said embodiment, A wavy thread may be formed in a nut and may be formed in both a volt | bolt and a nut.

  The cycle of the screw thread may be other than 90 °, for example, 120 ° at which the wave number at one turn of the screw is 3, 180 ° at which the wave number at one turn is 2, and 60 ° at which the wave number at one turn is 6. . That is, the wave number of the thread of the locking screw of the present invention may be an integer that can divide 360 degrees of the screw, and has a wave number of 3 to 8, more preferably 4 to 6 in one turn. Although it is good, it can be set as appropriate according to the application and size. Furthermore, the values of the maximum lead angle and the minimum lead angle may be set as appropriate according to the use and performance of the screw, and the screw may be applied to a multi-thread screw in addition to a single thread. is there.

10 Bolt 12 Male thread 14 Nut 16 Fixed member 18, 22 Thread 20 Female thread

Claims (5)

In the locking screw used to fix the fixed member with male and female screws,
The thread of the male screw is formed in a wave shape along the screw winding, and the lead angle changes periodically,
With respect to the average lead angle of the male screw, the maximum amount of change in the positive direction and the negative direction of the lead angle with respect to the average lead angle is substantially equal to the average lead angle,
The male screw and the female screw are screwed together, and in the state before the axial force due to tightening is applied , the male screw and the male screw and the screw according to the amplitude of the lead angle with respect to the helical winding of the wavy thread A locking screw, wherein the female screw thread is displaced by causing displacement. In the locking screw used to fix the fixed member with male and female screws,
The thread of the female screw is formed in a wave shape along the screw winding, and the lead angle changes periodically,
With respect to the average lead angle of the female screw, the maximum change amount in the positive direction and the negative direction of the lead angle with respect to the average lead angle is substantially equal to the average lead angle,
The male screw and the female screw are screwed together, and in the state before the axial force due to tightening is applied, the male screw and the male screw and the screw according to the amplitude of the lead angle with respect to the helical winding of the wavy thread A locking screw, wherein the female screw thread is displaced by causing displacement.   3. The locking screw according to claim 1, wherein the wavy thread has a plurality of integer wave numbers that are divisible by 360 ° in one turn of the screw. 4.   4. The locking screw according to claim 3, wherein the wavy thread has a wave number of 3 or 4 in one circumference of the screw.   5. The locking screw according to claim 1, wherein the wavy thread is formed on at least one of a male screw and a female screw of a multi-threaded screw.

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