CN202118079U - Anti-loosening structure for thread connection - Google Patents

Abstract

The utility model relates to a screw connection anti-loosening structure. It consists of bolts, connecting nuts, lock nuts, and stop washers. Its technical scheme is: there are two kinds of threads, one large and one small, on the bolt, the large thread part is screwed with the connecting nut to play a fastening effect, and the small thread part is screwed with a lock nut to play an anti-loosening effect. The two threads have the same direction of rotation (usually right-handed), but different pitches, and the pitch of the small thread part is smaller than the pitch of the large thread part. The nominal diameter of the small thread part is smaller than the minor diameter of the large thread part, so that the connecting nut can be easily screwed in. When the connecting nut is loose and rotates in the direction of withdrawal, under the action of the friction force of the joint surface, the locking nut also rotates at the same time, but because the pitch of the locking nut is smaller than that of the connecting nut, the withdrawal of the connecting nut is prevented, which plays a role Anti-loose effect. A stop washer can be added between the lock nut and the connecting nut, and the anti-loosening effect will be better.

Description

A threaded connection anti-loosening structure

technical field

The utility model relates to a mechanical connection, in particular to a screw connection anti-loosening structure. the

Background technique

Threaded connection is a common connection method in mechanical design. Under the condition of small static load and temperature change, the threaded connection can meet the self-locking condition, and the threaded connection may not loosen when tightened. However, due to the impact, vibration or variable load of the machine during the working process, the friction between the screw pairs may decrease or disappear instantly. If this phenomenon is repeated many times, the threaded connection will loosen. If there is looseness, it will affect the normal operation of the machine and even cause serious accidents. Therefore, the anti-loosening of threaded connections must be considered when designing threaded connections. the

The fundamental problem of threaded connection anti-loosening is to prevent the relative rotation of the screw pair. Among them, the "top nut" is a method of anti-loosening by using the principle of friction. The two nuts are tightened against each other, and the bolt screwing section is pulled while the nut is pressed, so that Make the spiral pair longitudinally compressed. However, the threads of the two nuts in the commonly used counter nut structure are the same thread, that is, the diameter, direction of rotation, pitch, etc. are the same. When the two nuts rotate at the same time, the friction force generated by the pressure between the two nuts will not act as resistance. Therefore, The structure can be improved to improve the anti-loosening effect. the

Contents of the invention

The purpose of the utility model is to provide a screw connection anti-loosening structure. the

The technical scheme of the utility model:

There are two kinds of threads, one large and one small, on the bolt (1). The large threaded part (102) is screwed together with the connecting nut (3) for fastening, and the small threaded part (101) is screwed together with the lock nut (2) to prevent loose effect. The two threads have the same direction of rotation (usually right-handed), but different pitches, and the pitch of the small thread part (101) is smaller than the pitch of the large thread part (102). The nominal diameter of the small threaded part (101) is smaller than the minor diameter of the large threaded part (102), so that the connecting nut (3) can be screwed in conveniently. The anti-loosening principle of this technical solution is: when the connecting nut (3) is loose and rotates in the direction of withdrawal, under the action of the friction force of the joint surface, the lock nut (2) also rotates at the same time, but due to the lock nut (2) ) is less than the pitch of the connecting nut (3), which prevents the withdrawing of the connecting nut (3) and plays an anti-loosening effect. If a stop washer (4) is added between the lock nut (2) and the connection nut (3), the anti-loosening effect will be better.

Beneficial effect: the structure is simple, the direction of rotation of the two threads is the same, and the installation and disassembly are convenient. the

Description of drawings

Figure 1 and Figure 2 are schematic diagrams of threaded connections without and with stop gaskets respectively. 1-bolt, 101-small thread part, 102-large thread part, 2-lock nut, 3-connection nut, 4-stop washer. the

Detailed ways

Option 1 is a threaded connection without a stop washer, as shown in Figure 1. When the connecting nut (3) is loose and rotates in the direction of withdrawal, under the action of the friction force of the joint surface, the lock nut (2) also rotates at the same time, but because the pitch of the lock nut (2) is smaller than that of the connecting nut (3) The thread pitch prevents the withdrawal of the connecting nut (3) and plays an anti-loosening effect. the

Option 2 is a threaded connection with a stop washer, as shown in Figure 2. After adding the stop washer 4, the two nuts must rotate simultaneously. Because the pitch of the two nuts is different, the locking nut (2) has stopped the connecting nut (3) from rotating, which plays an anti-loosening effect. the

Claims (2)

1. thread connection anti-loose structure is characterized in that: bolt (1) two kinds of screw threads of size are arranged, two thread rotary orientations are identical, but pitch is different, the pitch of minor thread part (101) is less than the major thread pitch of (102) partly; The nominal diameter of minor thread part (101) is less than the path of major thread part (102).

2. thread connection anti-loose structure according to claim 1 is characterized in that and can between locking nut (2) and attaching nut (3), add 1 locked spacer (4).

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