WO2012122829A1

WO2012122829A1 - Self-tightening lock nut

Info

Publication number: WO2012122829A1
Application number: PCT/CN2011/083541
Authority: WO
Inventors: 杨志清
Original assignee: Yang Zhiqing
Priority date: 2011-03-11
Filing date: 2011-12-06
Publication date: 2012-09-20
Also published as: CN201944075U

Abstract

A self-tightening lock nut, the nut having the thread pitch (t) being smaller or greater than the thread pitch of a standard nut of the same specification, and the value of a pitch difference between the nut and the standard nut being 1% to 6% of the pitch of the standard nut. Since a pitch difference exists between the pitch of the nut and that of a fitting bolt, during fitting, the pitch difference gradually accumulates as the nut is gradually screwed in. In this way, a compression force and the prevailing torque are produced between thread engagement surfaces, thereby producing an anti-loosening effect. Accordingly, a self-tightening lock nut with a simple structure, convenient use, high operability and a desirable anti-loosening effect is provided, and can be widely applied in railways, bridges, turnouts, automobiles, machineries and situations with long-time vibration and requiring safety fastening capable of resisting loosening.

Description

Self-tightening locknut

Technical field

The utility model relates to a fastener, and more particularly to a self-tightening locknut.

Background technique

Nuts are widely used fasteners today and are often used with bolts. For the size specifications of the nuts, there are detailed standards in the industry. Under normal circumstances, we try to use standard parts for the convenience of processing, purchasing and even use. Nut lock is a topic that has always been highly valued by the engineering community. Because the loose nut is loose, the function of the product is reduced or invalid. The heavy result is the collapse of the engineering or equipment structure, and may directly cause a major safety accident, so the nut is loose. It should not be underestimated. In equipment facilities such as railway tracks and automobiles that are related to personal safety, it is especially important to take nuts as a major event. At present, there are many ways to prevent the nut from loosening. It is more common to add accessories or accessories, such as adding a spring washer or a backing washer, using a back nut, installing a split pin, and filling a thread glue. These methods have certain effects under normal use conditions, but in high temperature, humidity, strong vibration and frequent harsh environments, such as railway tracks, the anti-loose function is extremely easy to lose, and the anti-loose method needs to be supplemented. The cooperation of the auxiliary materials increases the cost invisibly. In some cases, the nut is loosened by machining the nut's own structure. For example, there is a nut that is machined by a tap that deliberately removes a portion of the tapped cusp, and the nut is left on each thread of the nut. When the next protrusion is engaged with the bolt, the pressing force when the protrusion is pressed against the screw thread surface is tightened and loosened, but the nut has a large resistance at the beginning of screwing with the bolt. It is necessary to use the tool from the beginning to the end. It cannot be pre-screwed in place like a normal nut. This makes it easy for the screw and the bolt to be in position when screwing, which leads to cooperation. Skewed, unable to tighten. A utility model patent with the publication number CN86204074U discloses a locknut on July 22, 1987. The utility model comprises an eccentric and tapered male nut and an eccentric and tapered female nut, each The nut is provided with an eccentric obstruction point. When the nut is tightened, due to the eccentric structure, the two nuts are pressed against each other on the uneven surface of the contact surface to prevent loosening. The utility model has strong locking force, and because of the interlocking, only one nut needs to be screwed, instead of having to be counter-rotating when the common top nut is locked, the utility model needs special processing in pairs. Nut, structure is much more complicated than standard parts, high manufacturing cost, inconvenient operation

Summary of the invention

In order to overcome the existing locknuts or the accessories of the auxiliary parts, or to specially process the matching parts, or to process special shapes, the structure is complicated, the cost is increased, the use is inconvenient, and the operability is poor. The new type provides a self-tightening locknut, which does not require any auxiliary accessories or additional components, and has a simple structure, convenient use, strong operability and good anti-loose effect.

The technical proposal of the utility model is: a self-tightening locknut, the pitch of the thread is smaller than the standard screw of the same specification The female thread pitch, the pitch difference between the nut and the standard nut is 1% to 6% of the standard nut pitch. When the standard nut and the standard bolt are matched, the pitch of the nut and the pitch of the bolt are equal, and the screwing of the nut and the bolt is relatively easy until the nut and the bolt head are pressed against each other on both sides of the fastening object, the nut and the bolt Before the threaded surface, a large pressing force is generated. Before this, the nut and the bolt are always in a clearance fit, so that there is almost no mutual pressing force between the screwing surfaces. The thread pitch of the present invention is intentionally processed to be slightly smaller than the thread pitch of a standard nut of the same specification, but the nut can be used in combination with a standard bolt, and the threaded fit between the two is not strictly a precise fit. Although the nut and the bolt are still matched with each other at the beginning of the screwing, after the thread is twisted for a long time, the screwing surface of the thread will be squeezed by the force difference, and the mutual pressing force is generated, but due to the processing Note that the pitch difference between the nut pitch and the standard nut pitch is controlled to a suitable value, and the fastener material itself has a certain elastic deformation ability, so the pressing force between the screwing surfaces at the initial stage of the pressing force is generated. Smaller, the nut can still be screwed by hand, and the cooperation of the nut and the bolt is converted into a transition fit. Continue to screw, the pitch difference continues to accumulate, the pressing force between the screwing surfaces is further increased, the screwing resistance is getting larger and larger, and finally the tool must be used to continue the screwing. At this time, the cooperation between the nut and the bolt has been changed. For interference fit. After the whole nut is screwed on the bolt, the pitch difference is no longer accumulated, the pressing force between the screwing surfaces is kept constant, and the value of the pressing force is obtained after the nut and the bolt head are pressed on both sides of the fastening object. It changed because of the reaction force of the fastening object. In summary, the working principle of the utility model differs from the standard one in that before the bolt head and the nut are pressed against the fastening object, there is already a strong pressing force between the screwing surfaces of the screw, which is exactly this The pressing force compresses the screwing surface to produce a loosening torque, which acts as a loosening effect. The pressing force is gradually increased. In the initial stage, the pressing force is extremely small. At this time, the nut of the present invention can be quickly screwed into place on the bolt only by using the standard member. The thread is positioned to match the position until the nut and the bolt complete the thread alignment. After the deviation is not possible, the pressing force is gradually increased until the nut can no longer be screwed by hand, so it is convenient to use and standard. The usage of the parts is very close, except that the tools need to be used all the time after the nuts are all screwed onto the bolts. In order to be able to be used with the corresponding standard bolt standard to ensure the practicability and easy to promote the utility model, under the premise that the thread type, the thread specification and the like refer to the standard part, the nut thread of the utility model and the standard nut thread The pitch difference value must be controlled within a reasonable range. If the ratio of the pitch difference value to the standard nut pitch of the same specification is less than 1%, the pressing force between the nut and the bolt threading surface and the anti-loose torque are too small, and the anti-loose effect is not obvious; if it is greater than 6%, the thread is threaded. The pressing force between the screwing surfaces and the anti-loose torque are too large, and the operability is not strong. The utility model can be widely applied to the fields of railways, bridges, vehicles and machinery.

Preferably, the number of turns of the nut is from 3 to 9 turns. In the case where the pitch is determined, the number of turns determines the multiple of the total accumulated pitch difference after the nut is integrally screwed onto the bolt. In theory, the thicker the nut, the more the number of threads, the more the cumulative pitch difference, the greater the compression force and the anti-loose torque between the screw surfaces, and the better the anti-loose effect. but if Excessive number of thread turns, resulting in excessive lock-off torque, too large to operate, or damage to the thread, obviously loses its practical significance. Therefore, when machining the nut, the number of threads of the nut is controlled within the range of 3 to 9 turns, which can not only receive the anti-loosening effect, but also have operability.

Preferably, the thread of the nut is a triangular thread. The triangle is the most commonly used type of fastener thread, so the nut of the nut is made into a triangle, which can be used with the bolts of the mainstream system, so that it has good practicability.

Preferably, the nut thread angle is 60° or 55°. 60° is the standard profile angle of the metric thread, 55° is the standard profile angle of the inch thread, and the profile angle of the nut thread is machined according to the standard. It is also convenient for use with the existing standard parts, making the nut have wide applicability. .

The utility model can also adopt another technical solution as follows: A self-tightening locknut whose thread pitch is larger than the thread pitch of a standard nut of the same specification. The thread pitch of the utility model is intentionally processed to be slightly larger than the thread pitch of the standard nut of the same specification, and the nut can be used together with the standard bolt, after the screwing, even if the nut has not been pressed against the bolt head on both sides of the fastening object, the thread The mutual squeezing force is also generated between the screwing surfaces due to the accumulation of the pitch difference, and the locking torque is generated.

The beneficial effects of the utility model are:

It does not need any accessory accessories or additional matching components, and can be loosened by its own structural features, so the structure is simple, and the manufacturing and use cost is low;

The method of use is close to the use method of the standard parts, and the operability is strong and the use is convenient;

By controlling the key processing parameters within a reasonable range, a strong anti-loose torque can be obtained, and the anti-loose effect is good.

DRAWINGS

The present invention will be further described below in conjunction with the specific embodiments of the drawings.

Figure 1 is a schematic view of the structure of the present invention;

Figure 2 is a cross-sectional view of the present invention;

Fig. 3 is a schematic enlarged view of the structure A in Fig. 2.

In the figure, d-thread nominal diameter, d _r thread inner diameter, d ₂ - thread diameter, α-thread profile angle, t-thread pitch, H-nut thickness.

detailed description

Example 1

As shown in Figure 1, Figure 2 and Figure 3, a self-tightening locknut with 7 and 3/10 turns of thread, the nut size is coarse teeth M24, the thread inner diameter is 20.90mm, and the thread diameter d ₂ is 22.30mm, thread nominal diameter d is 24.00mm, nut thread is triangular thread, thread profile angle α is 60°, thread pitch t is 2.95mm, and standard coarse tooth M24 Compared with the pitch of the nut of 3.00 mm, there is a pitch difference of 0.05 mm. The remaining dimensions are in accordance with national standards. The nut is made of 45 steel slab. After hot forging and multi-pass hot forging, it is turned and tapped by processing equipment specializing in processing such nut, and heat treatment, quenching and tempering treatment HRC22 28 and blackening oil Wait for post processing.

Example 2

A self-tightening locknut with a size of M24 and a thread pitch t of 3.05mm. The rest are the same as in the first embodiment.

Example 3

Self-tightening locknut, the specification is coarse tooth M5, the inner diameter of the thread is 4.23mm, the diameter d ₂ is 4.56mm, the nominal diameter d of the thread is 5.00mm, the thickness of the nut is 3.5mm, and there are 4 3/10 ring thread, thread pitch t is 0.76mm, different from the pitch of the corresponding coarse tooth M5 standard nut 0.80mm. The remaining dimensions are processed according to national standards.

Example 4

Self-tightening locknut, the specification is coarse tooth M48, thread inner diameter ^ is 42.65mm, medium diameter d ₂ is 44.94mm, thread nominal diameter d is 48.00mm, nut thickness H is 38.00mm, a total of 7 3/5 turn thread, thread pitch t is 4.94mm, different from the corresponding coarse tooth M48 standard nut 5.00mm pitch. The rest are the same as in the first embodiment.

Example 5

Self-tightening locknut, specification is 1/2 inch, thread inner diameter ^ is 10.300mm, medium diameter d ₂ is 11.345mm, thread nominal diameter d is 12.700mm, number of teeth per inch is 12, nut thickness H It is 12.50mm, with a total of 6 turns of thread, the thread pitch t is 2.077mm, which is different from the pitch of 2.117mm of the standard nut of the corresponding 1/2 inch 12 teeth/inch. The remaining dimensions are processed according to national standards.

The nut of the utility model is used in combination with the standard bolt of the same specification. In the initial stage of screwing the bolt and the bolt, only a small number of thread faces are overlapped between the nut and the bolt, because the pitch of the nut and the standard nut pitch are used. The difference is very small, does not affect the clearance fit between the nut and the bolt in this stage. In this stage, the nut can be screwed by hand to position it on the bolt to obtain support without skewing; continue to screw, wait for the nut to When the screwing distance on the bolt reaches about 70% of the thickness of the nut, due to the accumulation of the pitch difference, the fit between the nut and the bolt is not as loose as the initial stage, and has been converted into a transition fit. The squeezing force has been generated, and the accompanying anti-loose torque, but it is still weak, so this stage can still rely on hand-force screwing; continue to screw, the pitch difference continues to accumulate, the cooperation between the nut and the bolt gradually The self-transformation state is changed to the state of interference. When the nut is close to the integral screw, the pressing force between the screwing surfaces and the anti-loose torque are already quite large. Thereafter, as long as the nut is entirely on the bolt, whether it is screwed in or out, it must be done by means of a tool.

Claims

Rights request

A self-tightening locknut, characterized in that the pitch of the thread is smaller than the thread pitch of a standard nut of the same specification, and the pitch difference between the nut and the standard nut is 1% to 6 of the pitch of the standard nut. %.

2. The self-tightening locknut according to claim 1, wherein the nut has a number of turns of 3 to 9 turns.

3. A self-tightening locknut according to claim 1 or 2, characterized in that the thread of the nut is a triangular thread.

4. A self-tightening locknut according to claim 3, wherein the nut has a thread profile angle of 60 or 55.

5. A self-tightening locknut, characterized in that the pitch of the thread is larger than the thread pitch of a standard nut of the same specification, and the pitch difference between the nut and the standard nut is 1% to 6 of the pitch of the standard nut. %.

The self-tightening lock nut according to claim 5, wherein the nut has a number of turns of 3 to 9 turns.

7. Self-tightening locknut according to claim 5 or 6, characterized in that the thread of the nut is a triangular thread.

8. A self-tightening locknut according to claim 7, wherein the nut has a thread profile angle of 60 or 55.