JPH0262725B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a locking nut.

a nut having a circular recess concentric with the female threaded shaft;
In combination with a nut having a circular protrusion eccentric to the female threaded shaft to fit into this recess, the bolt male thread is formed based on the contact between the inner peripheral surface of the recess and the outer peripheral surface of the projection. Double nuts are well known, which prevent loosening by interference of female nut threads.

However, with this type of locking double nut, if the inner circumferential surface of the recess and the outer circumferential surface of the protruding part come into contact with each other too strongly, fatal damage such as breaking the bolt or seizing the contact part may occur. On the other hand, if the contact pressure between the inner circumferential surface and the outer circumferential surface is weak, there is a problem in that a reliable effect of preventing the nut from loosening cannot be obtained.

The present invention has been made in view of the above points,
The purpose is to provide a double nut that can effectively and reliably prevent loosening without causing damage to the bolts or other joints.

According to the invention, the object comprises: a first nut;
A tapered cylindrical protrusion with a tapered tip provided on one end surface of the first nut, a plurality of grooves provided on the other end surface opposite to the one end surface of the first nut, and a second nut. a nut, and an inner diameter portion smaller than the maximum diameter of the tapered cylindrical protrusion, and the second
a cylindrical recess for fitting with the tapered protrusion provided at the center of one end face opposite to the one end face of the first nut of the nut, the tapered cylindrical protrusion and the cylindrical recess; The double nut is characterized in that the contact interference force exerted by the inner diameter portion of the recess on the outer circumferential surface of the protrusion when the two are fitted together is elastically absorbed by the plurality of grooves. achieved.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

In Figures 1, 2 and 3, Nut 1
is the nut body 2 and the second nut body 2.
It consists of a cylindrical protrusion 4 formed on the end surface 3, which is the lower side in the figure.

Further, on the end surface 5 of the nut body 2, which is the upper side in FIG. 2, two grooves 6, 6 are formed at symmetrical positions with respect to the axis 7 of the nut 1, respectively.
These grooves 6, 6 have an extension line of each groove aligned with the axis 7.
The respective depths 8 in the direction along the axis 7 are arranged so as to pass through the nut body 2.
It is formed so as to extend beyond the thickness 9 of the protrusion 4 in this direction and reach the middle of the thickness 10 of the protrusion 4 in that direction. In the case of a square nut as in this specific example, the grooves 6, 6 are preferably provided at the center of the engagement surface 11 with a tightening tool such as a spanner. A chamfered portion 12 is also formed on the end face 5.

The nut body 2 and the cylindrical protrusion 4 each include
A continuous internal thread 13, which is arranged concentrically with the axis 7 and has a root diameter R, is formed to pass through the nut 1.

The cylindrical protrusion 4 is formed so that its diameter gradually decreases as it moves away from the end surface 3, that is, it has a tapered shape. For example, in FIGS. 3 is the largest diameter part closest to R1, and the smallest diameter part which is the tip 14 of the protrusion 4 is R2, and R1>R2, these R
Diameter difference between 1 and R2 and thickness of cylindrical protrusion 4
10, the above-mentioned taper shape, in other words, the taper angle a is determined from each. Tip 14 of protrusion 4
A chamfered portion may be formed.

4 and 5, the nut 20 has a cylindrical recess 22 formed on the inner peripheral surface 26 of the nut 20 on the end face 21 side.

The recess 22 is formed concentrically with respect to the axis 23 of the nut 20. The recess 22 has a depth 24 approximately equal to the thickness 10 of the projection 4 of the nut 1. Furthermore, the recess 22 has a diameter R3 R1>R3>R2, which is an intermediate value between the diameter of the projection 4, ie the maximum diameter R1 and the minimum diameter R2 of the tapered projection 4.

The nut 20 further has an internal thread 25 arranged concentrically with the recess 22 . The root diameter R of the female thread 25 is equal to the root diameter R of the female thread 13 of the nut 1.
Further, the female thread 25 passes through the nut 20.

A chamfered portion 27 is formed on the peripheral edge of the end surface 21 of the nut 20. The chamfer angle a1 of the chamfered portion 27 is preferably 30 degrees.

Incidentally, the pitches of the female threads 13 and 25 are also configured to be equal to each other.

Nut 1 and Nut 2 configured as above
As shown in FIG. 6, the double nut according to the present invention, which is used by combining two nuts 1 and 20, is a double nut that extends upward from the hole 31 of the object 30 when tightening the object 30 with the nuts 1 and 20. The nut 20 is screwed onto the protruding bolt 32 and tightened onto the object 30 with a predetermined torque.
After this state, the nut 1 is screwed onto the bolt 32, and the protrusion 4 of the nut 1 is fitted into the recess 22 of the nut 20. FIG. 6 shows a state in which the nut 1 is screwed into the bolt 32 and moved in the direction of the arrow 33 from the first position P1 to the second position P2. The nut 1 is configured to eventually move to the third position P3, and in this state, the maximum loosening prevention effect can be obtained. That is, the cylindrical wall portion 16 of the protruding portion 4 of the nut 1 is aligned with the recess 22 of the nut 20.
When the nut 2 of the cylindrical wall portion 16 of the protruding portion 4 is guided while touching the open end 28 as the inner diameter portion of the
0 contact position 34 with respect to the open end 28 of the recess 22
approaches the end face 3 of the nut 1. Therefore, since the outer diameter of the protrusion 4 is tapered, the open end 28 of the recess 22 strongly contacts and interferes with the cylindrical wall 16 of the protrusion 4, and the cylindrical wall 16 is aligned with the axis. 7,
23 (in the direction of arrow 36) (the nut 1 indicated by the broken line in Fig. 6)
condition). Here, on the end face 5 of the nut 1, there is a groove 6,
6, the above-mentioned displacement force acting on the cylindrical wall portion 16 deforms the grooves 6, 6 each having a width S in the normal state as shown in FIG. Let it be S1. That is, the width of the grooves 6, 6 elastically changes depending on the pressing displacement force, and absorbs the pressing displacement force. In other words, the grooves 6, 6 are
The nut 1 constitutes means for elastically absorbing the aforementioned displacement force.

Therefore, as described above, in the final fitted state between the protrusion 4 and the recess 22, that is, in the state in which the nut 1 moves to the position P3, the width of the grooves 6, 6 becomes the minimum, and the nut 1 is in the maximum deformation state, and the female thread 1
3 strongly elastically presses the flank surface of the male thread 35 of the bolt 32, and the female thread 13 and the male thread 35 contact and interfere with each other, thereby reliably preventing the nut 1 from loosening against the bolt 32.

Furthermore, in the above-mentioned specific example, a set of grooves 6, 6 were provided in the end surface 5 of the nut 1 as a means for the nut 1 to elastically absorb the displacement force. As shown in FIG. 9, a plurality of sets of grooves 6, 6 may be provided. In this second specific example, three sets of grooves 6, 6 are formed, and the relative angle with each groove is 60 degrees. The number of sets and relative angles of these grooves may be appropriately selected as required.

As described above, according to the present invention, when fitting the tapered cylindrical protrusion and the cylindrical recess of the pair of nuts,
Due to the contact interference between the protrusion and the recess, the force applied to the nut can be effectively and gradually absorbed by the pair of grooves formed on the end face of one of the nuts. There is no damage to the external thread surface, so even if the nut is repeatedly installed and removed, the locking effect of the nut will not deteriorate, and even if a shocking external force is applied repeatedly to the nut, Can maintain a locking state,
It is possible to provide a double nut that can have a reliable locking effect.

[Brief explanation of the drawing]

1 is a plan view of one of the double nuts according to the present invention, FIG. 2 is a partially sectional front view of the nut shown in FIG. 1, and FIG. 3 is a top view of the nut shown in FIG. 1. FIG. 4 is a bottom view of the double nut according to the present invention, and FIG.
4 is a partially sectional front view of the nut shown in FIG. 4, FIG. 6 is an explanatory diagram showing a state in which the double nut according to the present invention is screwed onto a bolt to tighten a member to be tightened, and FIG. 7 is a diagram showing the present invention. FIG. 8 is a partially sectional front view of the nut shown in FIG. 7, and FIG. 9 is a plan view of one of the double nuts of another embodiment of the double nut according to the invention. It is a bottom view. 1, 20... Nut, 4... Protrusion, 6...
Groove, 22... recess.

Claims (1)

[Scope of Claims] 1. A first nut, a tapered cylindrical protrusion with a tapered tip provided on one end surface of the first nut, and a second nut on the other side opposite to the one end surface of the first nut. a plurality of grooves provided on an end surface, a second nut, and a diameter smaller than the maximum diameter of the tapered cylindrical protrusion, the second nut facing one end surface of the first nut; a cylindrical recess for fitting with the tapered protrusion provided at the center of one end surface, and the diameter of the recess when the tapered cylindrical protrusion and the recess are fitted; The contact interference force on the outer peripheral surface of the protrusion by the nut wall surface that defines
A double nut that is elastically absorbed by the plurality of grooves. 2. The plurality of grooves are a pair of grooves arranged symmetrically with respect to the axis of the nut, and the axis exists in the extension direction of each groove. The double nut described in item 1. 3. The double nut according to claim 2, wherein a plurality of pairs of grooves are provided.