JPS631047Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a nut loosening prevention device.

A locking nut is formed by screwing two nuts onto a bolt and pressing the two nuts against each other, for example, a recess in the shape of an inverted truncated cone having a central axis that coincides with the axis of the nut. Using a lower nut and an upper nut provided with an inverted truncated conical protrusion having a central axis slightly eccentric with respect to the axis of the nut,
The lower nut is first tightened to the bolt, and then the upper nut is tightened to the bolt, so that the upper nut overlaps the lower nut and the recess and the protrusion are brought into contact engagement,
A locking nut is known in which a lower nut is caused to interfere with a bolt by an eccentric protrusion.

However, this type of locking nut is
Because it is necessary to thread each nut onto the bolt, the nut tightening process becomes complicated and time-consuming, and the recesses and protrusions are simply shaped like a truncated cone. Therefore, if the recess and the protrusion are strongly pressed together, this pressure-welded part is likely to seize, and conversely, if the upper nut and lower nut are not pressed strongly, they will rotate relative to each other in the direction of loosening.
It tends to come loose easily.

Also known is a torque-increasing locking nut in which the nut body is provided with an interference portion that interferes with the male thread of the bolt. However, with this type of torque-increasing nut, it is necessary to apply a large torque to the nut when screwing the nut into the bolt, and the nut cannot be screwed in so easily.

This invention was made in view of the above points,
The purpose is to provide a nut loosening device which requires only a single nut, allows the nut to be easily screwed in, and has a reliable nut loosening prevention effect.

That is, the nut loosening device of the present invention includes a member having a hole with a diameter larger than the nominal diameter of the bolt;
A nut that is tightened onto the member through a bolt inserted into a hole in the member, an engaging portion provided in the central portion of the nut on the seat side, and a nut that is engaged with the engaging portion. an engaged part provided around a hole of the member, the engaging part and the engaged part being formed of a recess and a protrusion fitted into the recess,
An annular guide surface is provided at the open end of the recess, and a portion of the recess adjacent to the annular guide surface is formed as a cylindrical locking surface extending along the axis of the nut. , an annular guide surface is provided on the side circumferential surface of the protruding end of the protruding portion, corresponding to the annular guide surface of the recess, and a side circumferential surface of the protruding portion adjacent to the annular guide surface of the protruding portion The surface is formed as a cylindrical locking surface that extends along the axis of the nut in correspondence with the cylindrical guide surface of the recess, and the surface is formed as a cylindrical locking surface that extends along the axis of the nut, and the surface is formed as a cylindrical locking surface that corresponds to the cylindrical guide surface of the recess and of the engaging portion. In order to bring the cylindrical locking surfaces into contact with each other, the center of either the cylindrical locking surface of the recess or the cylindrical locking surface of the protrusion is eccentric with respect to the axis of the nut. It is characterized by

Next, a preferred embodiment of the present invention will be explained based on the attached drawings.

In the figure, reference numeral 1 denotes a nut, and a protrusion 3 is provided at the central portion of the nut 1 on the seat surface side, and extends integrally downward from the seat surface 2. The protruding part 3 has a cylindrical part 4 as a locking surface and an inverted truncated conical part 5 formed by gradually reducing the diameter of the outer periphery downward from the cylindrical part 4. The center 7 of the protrusion 3 is eccentric by a value ε with respect to the axis 8 of the female thread 6, which is the axial center line of the nut 1. The female thread 6 is also formed on the inner circumferential surface of the protrusion 3.
In this way, the side peripheral surface of the protruding end of the protruding portion 3 of the nut 1 is provided with an annular guide surface constituted by the side surface of the inverted truncated conical portion 5, and this annular guide surface of the protruding portion 3 is provided with The side circumferential surfaces of the adjacent protrusions 3, that is, the side circumferential surfaces of the cylindrical portions 4, are formed as cylindrical locking surfaces extending along the axis of the nut.

In FIG. 2, 9 is a member having a through hole 11 with a diameter slightly larger than the nominal diameter (outer diameter) of the bolt 10. Recess 1 as the formed engaged part
2 is provided. The recess 12 is formed in a shape that approximately corresponds to the shape of the protrusion 3, and the cylindrical portion 1
3 and an inverted truncated conical portion 14, the recess 1
The center of 2 substantially coincides with the axis of the through hole 11, and therefore also substantially coincides with the axis 8 of the female thread 6. An annular chamfer 16 is provided between the upper surface 15 of the member 9 and the cylindrical portion 13. As described above, the open end of the recess 12 of the member 9 is provided with an annular chamfered portion 16 as an annular guide surface, and the portion of the recess 12 adjacent to the chamfered portion 16, that is, the cylindrical portion 13, is shaped like a nut. It is formed as a cylindrical locking surface extending along the axis of the cylindrical locking surface.

The member 17 on which the member 9 is superimposed has the member 9
A through hole 18 corresponding to the through hole 11 is provided, and a bolt 10 inserted into the through hole 11, 18 is provided.
The nut 1 is tightened onto the members 9, 17 via the .

In the process of tightening the nut 1, when screwing the eccentric protrusion 3 of the nut 1 into the recess 12 of the member 9, the side surface of the truncated conical portion 5 as a guide surface of the protrusion 3 and the annular shape of the member 9 The chamfered portions 16 guide each other while contacting each other, and as shown in FIG. Surface and recess 12
The cylindrical portions 13 of the nut 1 contact and interfere with each other to prevent the nut 1 from loosening.

In this specific example, the protrusion 3 of the nut 1 is eccentric, and the protrusion 3 of the nut 1 is placed on the recess 12 of the member 9, which is formed in a shape corresponding to the shape of the protrusion 3 and is not eccentric. Since the protrusion 3 and the recess 12 contact and interfere with each other, a strong interference pressure is applied to the male thread of the bolt 10 and the female thread 6 of the nut 1. In particular, the projections 3 and 12 have cylindrical portions 4 and 1, respectively.
3 is provided, and the cylindrical portions 4 and 13
Since these contact and interfere with each other in opposing directions, a strong interference pressure is applied to the male and female threads in a direction perpendicular to the axis of the bolt 10, thereby preventing the nut 1 from loosening. In addition, since the cylindrical parts 4 and 13 contact and interfere with each other in a direction perpendicular to the axis of the bolt, even if the nut 1 is rotated in the direction of loosening, the contact interference between the cylindrical parts 4 and 13 is maintained. Nut 1 will not loosen easily.

In addition, in this specific example, the recess 12 of the member 9
is formed by a cylindrical portion 13 and an inverted truncated conical portion 14, but instead of this, an inverted truncated conical portion 14 is formed.
The cylindrical portion 13 is extended to the depth of the recess 1.
The inner circumferential surface of No. 2 may be formed into a cylindrical shape. Alternatively, the recess may be eccentric and the center of the protrusion may be aligned with the axis of the female thread of the nut.

In the specific example shown in FIG. 3, the nut 20 is provided with a recess 21 as an engaging portion, and the member 22 is provided with a protrusion 23 as an engaged portion. The inner peripheral surface of the recess 21 is provided with a cylindrical portion 24 and a truncated conical portion 25 extending upward from the cylindrical portion 24 with a gradually reduced diameter. A female thread 26 of the nut 20 extends upward from the top. The center of the recess 21 is eccentric with respect to the axis of the female thread 26. An annular chamfer 28 is provided between the seat surface 27 of the nut 20 and the cylindrical portion 24. The protrusion 23 of the member 22 is connected to the nut 2
The projecting portion 23 has a cylindrical portion 29 and a truncated conical portion 30 corresponding to the recess 21 of the member 22, and the center of the protrusion 23 substantially coincides with the axis of the through hole 31 of the member 22. 31 extends within the protrusion 23 and defines the inner circumferential surface of the protrusion 23 .

In this specific example as well, the truncated conical portion 30 of the protrusion 23 is formed as a guide surface for the recess 21 of the nut 20, and when the nut 20 is tightened onto the member 22 via the bolt 10, the nut 2
The recess 21 of 0 is guided by the truncated conical part 30, the cylindrical part 24 is locked with the cylindrical part 29, and as a result of mutual contact and interference, the nut 2 is securely tightened.
The locking effect of 0 can be reliably achieved in the same manner as in the above example.

In this specific example as well, the inner circumferential surface of the recess 21 may be formed into a cylindrical shape, or the center of the recess 21 may be aligned with the axis of the female screw, and the protrusion 23 may be formed eccentrically. It's okay.

In the specific example shown in FIG. 4, the nut 35 is provided with a protrusion 36 as an engaging portion extending downward around the axis of the female thread, and the protrusion 36 is connected to a cylindrical portion 37. The cylindrical portion 37 is formed with a spherical inverted truncated conical portion 38 whose side circumference is gradually reduced in diameter downward from the cylindrical portion 37 and is curved downward. Then, the protrusion 3 is placed on the surface of the member to which the nut 35 is tightened via the bolt.
A recess as an engaged portion having a shape corresponding to 6 is provided, and this recess is formed eccentrically with respect to the axis of the through hole of the member. In this case, a rounded annular chamfer may be provided at the upper end of the recess.

The cylindrical portion of the recess may be formed with a diameter slightly larger than the outer diameter of the cylindrical portion of the protrusion within the range where the cylindrical portion of the recess and the protrusion contact and interfere with each other. Furthermore, the inner circumferential surface of the recess may be formed into a cylindrical shape with a length comparable to the length of the protrusion.

In addition, in all of the above-mentioned examples, if the eccentricity of the recess or protrusion from the axis of the female thread (the axis of the through hole) is small, the locking effect of the nut decreases, and if it is large, the eccentricity within the recess This may make it difficult for the protruding part to fit into the nut, or the nut may be destroyed. However, in this invention, the amount of eccentricity can be adjusted to maintain a constant tightening force after the nut is tightened to an effective torque value, ensuring a secure locking effect. The nut is set within limits such that it is effective and there is no risk of the nut being destroyed. For example, when the nut thread is set as a JIS metric thread M12 x 1.75, it is preferable to set the eccentricity ε = 0.6. Further, the taper and curvature of the truncated conical portion and the spherical truncated conical portion of the protrusion are set appropriately for each pair of nuts, and the taper and roundness of the annular chamfered portion of the recess are also set appropriately.

Further, the member provided with the engaged portion that is engaged with the engaging portion of the nut may be formed of a washer, and for example, the washer may be provided with the recess 12 or the protruding portion 21.

As described above, according to the present invention, it is possible to eliminate the need to tighten two nuts as in the conventional double nut, and to simply screw in and tighten this nut using a single nut. It is possible to provide a nut loosening device that can apply strong interference pressure to the screw and the female thread of the nut, and can achieve a reliable nut loosening effect.

That is, in the present invention, there is provided a member having a hole with a diameter larger than the nominal diameter of the bolt, a nut that is tightened onto the member via the bolt inserted into the hole of the member, and a center portion of the nut on the seat side. Since it is formed of an engaging part provided and an engaged part provided around the hole of the member to be engaged with the engaging part, only a single nut can be used. To provide a nut loosening device that can have a reliable nut loosening prevention effect, and to smoothly accomplish nut tightening work that should originally be carried out efficiently and without any omissions as intended.

In addition, the nut loosening device of the present invention is
The engaging portion and the engaged portion are formed of a recess and a protrusion that is fitted into the recess, and an annular guide surface is provided at the open end of the recess. Adjacent portions of the recess are formed as cylindrical locking surfaces extending along the axis of the nut, and a side peripheral surface at the protruding end of the protrusion has an annular guide surface of the recess. A corresponding annular guide surface is provided, and the side peripheral surface of the protrusion adjacent to the annular guide surface is aligned with the axis of the nut in correspondence with the cylindrical locking surface of the recess. Since it is formed as a cylindrical locking surface that extends along the cylindrical locking surface, when screwing the nut onto the bolt, the annular guide surface formed at the protruding end of the protrusion and the open end of the recess are formed. The annular guide surfaces are in contact with each other and guide each other, and the protrusion can be easily and reliably fitted into the recess, and the nut tightening operation can proceed smoothly. The cylindrical locking surface and the cylindrical locking surface formed in the recess correspond to each other, so that the protrusion can be reliably locked in the corresponding recess. Since the locking surface extends along the axis of the nut, it is possible to control the force applied to the nut in the direction of loosening, thereby reliably preventing the nut from loosening.

Furthermore, in the nut loosening device of the present invention, the cylindrical locking surface of the recess and the cylindrical locking surface of the protrusion are arranged so that the cylindrical locking surface of the recess and the cylindrical locking surface of the protrusion contact and interfere with each other. Since either of the cylindrical locking surfaces of the protrusion and the recess are formed so that their centers are eccentric with respect to the axis of the nut, the cylindrical locking surfaces of the protrusion and the recess are They contact and interfere with each other, and strong interference pressure can be applied to the male thread of the bolt through which the nut is inserted and the female thread of the nut. In particular, protrusions and recesses
Each nut is provided with a cylindrical locking surface formed along the axial center line of the nut, and since the respective cylindrical locking surfaces contact and interfere with each other in opposing directions, the shaft of the bolt is A strong interference force is applied to the male thread and the female thread in the orthogonal direction, preventing the nut from loosening. In addition, since the respective cylindrical locking surfaces contact and interfere with each other in the direction perpendicular to the bolt axis,
Even if the nut is rotated in the loosening direction, the contact interference between the respective cylindrical locking surfaces can be maintained, and the effect of preventing the nut from loosening is achieved.

Therefore, according to the present invention, it is possible to eliminate the need to tighten two nuts as in the case of conventional double nuts, and to use a single nut, this nut can be easily screwed in and tightened, and the tightening work is also reduced. but,
To provide a nut loosening device that can be easily and reliably operated, can apply strong interference pressure to the male and female threads of a bolt, and has a reliable nut loosening effect.

[Brief explanation of the drawing]

Fig. 1 is an explanatory view showing a specific example of a nut used in the device of the present invention, and Fig. 2 is an explanatory cross-sectional view showing a state in which the nut shown in Fig. 1 is tightened onto a member via a bolt. , FIG. 3 is a cross-sectional explanatory view showing another specific example of the device of the present invention, and FIG. 4 is an explanatory diagram of another specific example of the nut used in the device of the present invention. 1... Nut, 2... Seat surface, 3... Protrusion, 4
...Cylindrical part, 5...Inverted truncated conical part, 9...
Member, 10... Bolt, 11... Through hole, 12...
...concavity.

Claims (1)

[Claims for Utility Model Registration] (1) A member having a hole with a diameter larger than the nominal diameter of the bolt, a nut that is tightened on the member through the bolt inserted through the hole in the member, and a seat for the nut. It consists of an engaging part provided in the center part of the surface side, and an engaged part provided around the hole of the member so as to be engaged with the engaging part, and the engaging part and the engaged part are provided around the hole of the member. A portion is formed of a recess and a protrusion fitted into the recess, and an annular guide surface is provided at the open end of the recess, and a portion of the recess adjacent to the annular guide surface is formed as a cylindrical locking surface extending along the axial center line of the nut, and an annular guide surface is formed on the side peripheral surface of the protruding end of the protruding portion in correspondence with the annular guide surface of the recess. The side peripheral surface of the protrusion adjacent to the annular guide surface of the protrusion has a cylindrical locking surface extending along the axis of the nut in correspondence with the cylindrical locking surface of the recess. The cylindrical locking surface of the recess and the cylindrical locking surface of the protrusion are formed as a stop surface so that the cylindrical locking surface of the recess and the cylindrical locking surface of the protrusion contact and interfere with each other. Either of the stop surfaces is a nut locking device whose center is eccentric to the axis of the nut. (2) The device according to claim 1, wherein the engaging portion is formed by a protrusion and the engaged portion is formed by a recess. (3) The device according to claim 1, wherein the engaging portion is formed as a recess and the engaged portion is formed as a protrusion. (4) The protruding portion has a cylindrical portion and a truncated conical portion extending from the cylindrical portion with a diameter gradually reduced, and the truncated conical portion defines a guide surface of the protruding portion. The device according to any one of claims 1 to 3, wherein the cylindrical portion defines a locking surface of the protrusion. (5) Utility model registration claim 4, wherein the inner circumferential surface of the recess is provided with a truncated conical portion and a cylindrical portion corresponding to the truncated conical portion and cylindrical portion of the protrusion, respectively. The device described in.