JP2009115297A - Lock-nut, its manufacturing method, and its jig for processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lock-nut capable of sufficiently securing insertion characteristics and fastening force on a bolt and being easily manufactured at low cost. <P>SOLUTION: In the lock-nut, an inclined surface 3 inclined against an axis is formed on an outer peripheral surface of a hexagonal nut by pressing the outer peripheral surface at one end side of the hexagonal nut specified by the JIS B1181, and a diameter of a screw hole of the hexagonal nut is reduced at one end side corresponding to the inclined surface 3. The inclined surface 3 inclined against the axis is formed on the three planes by pressing one end sides of the three planes arranged every other plane among the six planes forming the outer peripheral surface of the hexagonal nut. The diameter of the screw hole of the hexagonal nut may be reduced at one end side corresponding to the inclined surface 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a locking nut, a manufacturing method thereof, and a processing jig thereof.

  Bolts and nuts are one of the most basic mechanical elements and are used in various devices. When the device using bolts and nuts is stationary, the bolts and nuts are firmly fastened. However, loosening may occur in the fastening between the bolt and the nut due to vibration generated when the device is operated or when the device is transported. And the risk of adversely affecting other things including the human body as well as the failure or damage of the device due to the decrease of the fastening force and the complete loss of the fastening force. There is.

  Therefore, various means are taken in order to prevent loosening of the fastening between the bolt and the nut. One of the means is a loosening prevention structure using a double nut. This prevents the nuts from loosening by tightening the two nuts adjacent to each other, thereby applying an axial retaining force to the nuts.

  However, such a locking structure with a double nut is not preferable in terms of cost and work efficiency because two nuts must be tightened. There is also a problem that the two nuts rotate together and loosen after tightening.

  Therefore, a locking nut has been proposed in which the fastening force with the bolt is improved by one nut. For example, as shown in FIG. 15, the locking nut shown in Patent Document 1 includes a nut main body 110 in which a screw hole 110a is formed, and a truncated cone-shaped protrusion 100 in which a screw hole 100a is formed. And the press body 200 is pressed on the outer peripheral surface of this protrusion part 100, and the internal diameter of the screw hole 100a is reduced-diameter-deformed. On the other hand, the screw hole 110a of the nut body 110 is not reduced in diameter. This is for improving the fastening force with the bolt in the screw hole 100a of the protrusion 100 while ensuring the insertion of the bolt into the screw hole 110a of the nut body 110.

  Also, Patent Document 2 shown in FIG. 16 discloses a nut including a nut body 330 having a screw hole 330a and a truncated cone-shaped protrusion 300 having a screw hole 300a. The locking nut basically has the same configuration as that shown in FIG. 15, but the outer peripheral surface of the protruding portion 300 is formed into a hexagonal shape by pressing the protruding portion 300 with a mold 400 having a concave portion of a hexagonal weight. While being formed, the inner diameter of the screw hole 300a is reduced and deformed.

  Further, Patent Document 3 and Patent Document 4 disclose a method of manufacturing a locking nut by caulking a hexagon nut.

In Patent Document 3, as shown in FIG. 17, the screw hole is slightly deformed into an elliptical shape by pressing the side surface of the hexagon nut radially inward with a pin 500. In Patent Document 4, as shown in FIG. 18, one end surface of the hexagon nut is pressed with a pin 600. Thereby, the pitch of the threads near the pressed one end surface is narrowed.
JP 2001-334343 A Japanese Patent No. 2577258 JP-A-57-28647 Japanese Utility Model Publication No. 57-200722

However, the locking nut disclosed in Patent Documents 1 to 4 and the manufacturing method thereof have the following drawbacks.
Since the locking nut of Patent Document 1 or 2 has a special shape having a frustoconical protrusion, the manufacturing cost increases. Moreover, since the protrusion is attached to the nut main body, it becomes longer in the axial direction and it is difficult to save space.

  In the method of manufacturing the locking nut of Patent Document 3, generally, the pin 500 is pressed locally at the center of the side surface of the hexagon nut to reduce the diameter of the intermediate portion in the axial direction of the screw hole. However, since the screw hole is not so long in the axial direction, when the diameter of the intermediate portion in the axial direction of the screw hole is reduced as described above, the effect extends to both ends of the screw hole and on both ends of the screw hole. The diameter is also reduced. For this reason, it is easy to produce the malfunction that it is difficult to insert a volt | bolt in a screw hole, or it cannot insert. Further, when the side surface of the hexagon nut is pressed over a long range in the axial direction with the pin 500 having a large pressing surface, the screw hole continuously reduces in diameter along the axial direction. Also in this case, it is difficult or impossible to insert the bolt into the screw hole. Therefore, in the method of Patent Document 3, it is difficult to improve the fastening force while maintaining the bolt insertion property.

  The method of patent document 4 is improving the fastening force with a volt | bolt by narrowing the pitch of screw threads. Even if the screw pitch is narrowed, the fastening force with the bolt can be improved. However, the elastic deformation amount of the screw pitch is smaller than the elastic deformation amount in the radial direction of the screw hole. Therefore, once the bolt is fastened, the screw pitch is plastically deformed in the expanding direction and is not elastically restored. Therefore, there is a drawback that the loosening prevention function is remarkably lowered at the next fastening.

  In addition, there are nuts that improve the fastening force with bolts by attaching synthetic resin or metal plates to the screw holes, but the material costs for these synthetic resins and the manufacturing man-hours for attaching them increase. Therefore, it is not preferable.

  Therefore, in view of such circumstances, the present invention can sufficiently secure the insertion property and the fastening force with respect to the bolt, and can be manufactured easily and inexpensively, a method for manufacturing the locking nut, and its processing It is intended to provide a jig for use. In addition, the hexagonal nut manufactured using a mold having a draft angle is focused on the fact that one end of the screw hole has a small diameter, and by reducing the diameter of one end side of the screw hole, It is an object of the present invention to provide a method that makes it possible to manufacture a locking nut efficiently.

  According to the first aspect of the present invention, an inclined surface that is inclined with respect to an axis is formed on the outer peripheral surface of the hexagon nut by pressing the outer peripheral surface of one end of the hexagon nut defined in JIS B1181, thereby forming the inclined surface. Is a locking nut in which one end side of the screw hole of the hexagonal nut corresponding to is reduced in diameter.

  Here, the “inclined surface” includes a tapered surface that is inclined straight with respect to the axis of the hexagon nut, or a curved surface that is inclined while being curved with respect to the axis of the hexagon nut.

  When fastening the locking nut to the bolt, it is easy to insert the bolt from the other end side opposite to the one end side where the screw hole of the locking nut is contracted. It is possible to firmly fasten the bolt with the bolt. Further, since the amount of elastic deformation in the radial direction of the screw hole is relatively large, when the tightened locking nut is removed from the bolt, one end side of the screw hole is elastically deformed and returned to the original inner diameter reduced. Thereby, even if the locking nut is repeatedly fastened to the bolt, the locking function can be maintained well.

  According to a second aspect of the present invention, in the locking nut according to the first aspect, among the six planes constituting the outer peripheral surface of the hexagon nut, one end side of two planes facing opposite directions is pressed to An inclined surface that is inclined with respect to the axis is formed on a flat surface, whereby one end side of the screw hole of the hexagon nut corresponding to the inclined surface is reduced in diameter.

  The loosening prevention nut according to claim 2 has an advantage that the processing jig for pressing one end side of the two planes and the pressing jig for fixing the hexagon nut hardly interfere with each other. As a result, the hexagon nut can be held in a wide range by the holding jig and stably fixed.

  According to a third aspect of the present invention, in the locking nut according to the first aspect, by pressing one end side of three planes arranged every other plane among the six planes constituting the outer peripheral surface of the hexagon nut. In addition, inclined surfaces that are inclined with respect to the axis are formed on the three planes, whereby one end side of the screw hole of the hexagon nut corresponding to the inclined surface is reduced in diameter.

  The loosening prevention nut of claim 3 can be uniformly reduced in diameter in a wide range over the circumferential direction of the screw hole by pressing one end side of the three planes arranged every other face. It is. Further, there is an advantage that the processing jig can be easily centered with respect to the hexagon nut.

  According to a fourth aspect of the present invention, in the locking nut according to any one of the first to third aspects, the lower limit value of the inclination angle of the inclined surface with respect to the axis of the hexagon nut is set to 10 °, and the inclination The upper limit value of the angle is set to 45 °.

  If the inclination angle is set to be less than the lower limit of 10 °, the screw hole may be reduced in diameter at the other end portion opposite to the one end portion where the inclined surface of the hexagon nut is formed. This makes it difficult to insert the bolt into the screw hole. On the other hand, by setting the inclination angle to 10 ° or more, it is possible to maintain the insertion property of the bolt into the screw hole.

  On the other hand, if the inclination angle exceeds the upper limit of 45 °, the amount of narrowing of the screw pitch increases, but the amount of diameter reduction of the screw hole cannot be obtained sufficiently. Even if the screw pitch is narrowed, the fastening force with the bolt can be improved. However, since the amount of elastic deformation of the screw pitch is small, once it is fastened to the bolt, the screw pitch is plastically deformed in the expanding direction and is not elastically restored. Therefore, when the bolt is next fastened, the loosening prevention function is remarkably lowered.

  On the other hand, by setting the inclination angle to 45 ° or less, the diameter reduction amount of the screw hole can be sufficiently secured. Since the amount of elastic deformation in the radial direction of the screw hole is large, even if the locking nut is repeatedly fastened to the bolt, the locking function can be maintained.

  The invention according to claim 5 is the locking nut according to any one of claims 1 to 3, wherein a lower limit value of an inclination angle of the inclined surface with respect to an axis of the hexagon nut is set to 20 °, and the inclination The upper limit value of the angle is set to 30 °.

  As a result, it is possible to further improve the insertion of the bolt into the screw hole and to more effectively maintain the locking function. Further, even if the hex nut has a variation in the axial length, an error in the diameter reduction amount of the screw hole caused by the variation can be reduced.

  According to the sixth aspect of the present invention, the pressing surface of the processing jig is brought into pressure contact with the outer peripheral surface of one end of the hexagon nut defined in JISB1181 while being inclined with respect to the axis of the hexagon nut. This is a method of manufacturing a loosening prevention nut in which one end side of the screw hole of the hexagon nut corresponding to the inclined surface is subjected to diameter reduction processing by plastic processing the inclined surface on the outer peripheral surface.

  Since the hexagon nut defined in JISB1181 is used as the material for the locking nut of the present invention, it is simpler and less expensive than the conventional locking nut made of the specially shaped nut shown in FIGS. Can be manufactured. Moreover, the locking nut manufactured by the manufacturing method of this invention can improve the fastening force with a volt | bolt, supporting the insertion property of a volt | bolt. Furthermore, even if the locking nut of the present invention is repeatedly fastened to the bolt, the locking function can be maintained.

  The invention of claim 7 is the method of manufacturing a locking nut according to claim 6, wherein the hexagonal nut is forged by a die having a draft angle so that the inner diameter on one end side of the screw hole is smaller than the other end. The pressing surface of the processing jig is brought into pressure contact with the outer peripheral surface of the one end side of the hexagon nut while being inclined with respect to the axis of the hexagon nut, and In this method, one end side of the screw hole of the hexagon nut corresponding to the inclined surface is subjected to diameter reduction processing by plastically processing the inclined surface on the outer peripheral surface.

  By pressing the outer peripheral surface corresponding to one end side of the screw hole that has a small diameter in advance, the one end side of the screw hole can be efficiently reduced in diameter.

  The invention according to claim 8 is provided with a protrusion having a pressing surface on the jig body, and the pressing surface is arranged so as to be able to press-contact with an outer peripheral surface on one end side of the hexagon nut defined in JISB1181 in an axial direction. It is a jig for processing the provided locking nut.

  It is possible to reduce the diameter of one end of the screw hole of the hex nut by inclining and pressing the pressing surface to the outer peripheral surface on the one end side of the hex nut in the axial direction.

  According to the ninth aspect of the present invention, the rod is detachably attached to the jig body, and the rod is disposed on the outer peripheral surface on one end side of the hexagon nut defined in JISB1181 so as to be press-contacted while being inclined in the axial direction. It is a jig for processing a retaining nut.

  It is possible to reduce the diameter of one end of the screw hole of the hex nut by inclining and pressure-contacting the rod to the outer peripheral surface on the one end side of the hex nut in the axial direction. Also, if the rod breaks, it can be easily replaced with a new rod.

  Since the hexagonal nut defined in JISB1181 is adopted as the material for the locking nut of the present invention, it is simpler and less expensive than the conventional locking nut made of the specially shaped nut shown in FIGS. Can be manufactured. Further, the loosening prevention nut of the present invention can sufficiently secure the insertion property and the fastening force with respect to the bolt as compared with the loosening prevention nut that is pressed by pressing the side surface of the hexagon nut shown in FIG. Furthermore, even if the locking nut of the present invention is repeatedly fastened to the bolt, the locking function can be maintained satisfactorily. Therefore, unlike the locking nut manufactured by pressing the end face of the hexagonal nut shown in FIG. 18, the locking function is not significantly lowered by repeatedly fastening with the bolt.

  FIG. 1 is a perspective view showing a first embodiment of a locking nut according to the present invention. As shown in FIG. 1, the locking nut of the present invention has a nut body 1 having an outer peripheral surface configured in a hexagonal shape with six planes, and a screw hole 1 a penetrating in the center. . Of the six planes constituting the outer peripheral surface of the nut main body 1, the three grooved planes arranged on every other plane are respectively provided with the groove portions 2 each having a square groove shape. The concave portion 2 has an inclined surface 3 that is disposed to be inclined with respect to the axis L of the nut body 1 (or the center line of the screw hole 1a).

  2 is a cross-sectional side view of FIG. As shown in FIG. 2, the inclination angle α of the inclined surface 3 with respect to the axis L of the nut body 1 has a lower limit value of 10 ° and an upper limit value of 45 °. Furthermore, it is preferable that the lower limit value of the inclination angle α is 20 ° and the upper limit value is 30 °. In addition, the said inclination | tilt angle (alpha) is an angle which faces the nut main body 1 side formed between the axis line L of the nut main body 1, and the extension line M of the inclined surface 3 which cross | intersects it.

  Each concave strip 2 (inclined surface 3) is formed on one end side of the nut body 1, that is, on the upper end side in FIGS. And the internal diameter of the screw hole 1a of the one end side in which each concave strip part 2 was formed is formed by reducing in diameter. Specifically, the inner diameter of the screw hole 1a is reduced so as to gradually decrease toward the one end side so as to correspond to the inclination angle α of the inclined surface 3.

  3 and 4 show a second embodiment of the locking nut of the present invention. FIG. 3 is a perspective view of the locking nut, and FIG. 4 is a sectional side view thereof. In this embodiment, two round groove-shaped recesses are respectively provided on two planes arranged every two planes out of the six planes constituting the outer peripheral surface of the nut body 1, in other words, two planes facing opposite directions. Portions 4 and 4 are formed. The recess 4 has an inclined surface 5 that is disposed to be inclined with respect to the axis L of the nut body 1.

  As shown in FIG. 4, the lower limit value and the upper limit value of the inclination angle β with respect to the axis L of the nut body 1 of the inclined surface 5 are set similarly to the inclination angle α (see FIG. 2). The inclination angle β is an angle formed between the axis L of the nut body 1 and the extension line N of the inclined surface 5 intersecting the nut body 1 and facing the nut body 1 side.

  Each concave strip 4 (inclined surface 5) is formed on one end side of the nut body 1, that is, on the upper end side in FIGS. And the internal diameter of the screw hole 1a of the one end side in which each concave-line part 4 was formed is formed by reducing in diameter. Specifically, the inner diameter of the screw hole 1a is reduced so as to gradually decrease toward the one end side so as to correspond to the inclination angle β of the inclined surface 5.

  As described above, in FIGS. 3 and 4, portions with reference numerals other than those described above and with the same reference numerals as those in FIGS. 1 and 2 have the same configurations as those in FIGS.

  In the above-described two embodiments of the present invention, the concave portions are formed on the two or three planes of the outer peripheral surface of the nut body 1, but the concave portions may be formed on one plane or three or more planes. Good. Further, the number of the concave portions formed on one plane of the outer peripheral surface may be three or more, and the cross-sectional shape of the concave portions is not limited to the above-described square (rectangle) to round (arc). . Further, the inclined surface 3 may be formed over the entire longitudinal direction of one side of the nut body 1.

Next, the processing jig for the locking nut according to the present invention will be described.
5 and 6 show a first embodiment of the processing jig of the present invention. FIG. 5 is a plan view of the processing jig of the first embodiment, and FIG. 6 is a cross-sectional side view taken along the line AA of FIG. As shown in FIG. 5, the processing jig 6 includes a jig body 7 formed to extend in a trifurcated shape in a plan view. At the tips of the portions extending from the center of the jig body 7 at equal intervals (every 120 °) in the outer diameter direction, leg portions 8 extending downward in FIG. 6 are provided. And the protrusion part 9 is provided inside these leg parts 8. FIG.

  Each protrusion 9 has a pressing surface 10 facing downward in FIG. The pressing surface 10 is disposed so as to be inclined with respect to an axis X extending in the vertical direction in FIG. The inclination angle γ of the pressing surface 10 with respect to the axis X of the jig body 7 has a lower limit value of 10 ° and an upper limit value of 45 °. Further, the lower limit value of the inclination angle γ is preferably 20 °, and the upper limit value is preferably 30 °. In addition, the said inclination | tilt angle (gamma) is an angle which faces the front end side of the leg part 8 formed between the axis line X of the jig | tool main body 7, and the extension line Y of the press surface 10 which cross | intersects it.

  7 and 8 are views showing a second embodiment of the processing jig. FIG. 7 is a plan view of the processing jig of the second embodiment, and FIG. 8 is a cross-sectional side view taken along the line BB of FIG. As shown in FIG. 8, the processing jig 60 includes a jig body 70 having legs 12 extending downward in FIG. 8 at both ends, and a plurality of rods 11 having a round bar shape. In this embodiment, four rods 11 are arranged in total. Specifically, a pair of rods 11 and 11 are disposed adjacent to the two leg portions 12 and 12 of the jig body 70, respectively. As this rod 11, for example, a needle of a needle bearing used for a constant velocity universal joint can be applied.

  Two insertion holes 14 are provided through each leg 12, and the rod 11 is detachably inserted into the insertion holes 14. As shown in FIG. 8, in a state where the rod 11 is inserted through the insertion hole 14 and attached, a part of the rod 11 is exposed from the insertion hole 14 and disposed inside the leg portion 12. Further, although not shown in the drawing, a dropping prevention means such as a stopper may be provided so that each rod 11 is not dropped from the insertion hole 14.

  The insertion hole 14 is inclined with respect to the axis X extending in the vertical direction of FIG. Accordingly, each rod 11 is disposed in an inclined manner with respect to the axis X of the jig body 70 by being mounted in the insertion hole 14.

  The lower limit value and the upper limit value of the inclination angle δ with respect to the axis X of the jig body 70 of the rod 11 are set similarly to the inclination angle γ (see FIG. 6). The inclination angle δ is an angle formed between the axis X of the jig main body 70 and the extension line Z of the axis of the rod 11 and facing the distal end side of the leg portion 12.

Hereinafter, a method for manufacturing a locking nut using the processing jig of the first embodiment will be described.
As a material for the locking nut of the present invention, a hexagon nut defined in JISB1181 is used. In this embodiment, among the hexagon nuts defined in JIS B1181, one kind of hexagon nut in which the edge of the outer peripheral edge on one end side is formed round is used. The standard hexagon nut 15 is forged by a die having a draft angle, so that the diameter of the screw hole 15a on one end side having a rounded outer peripheral edge is slightly smaller than the diameter on the other end side opposite to that. It is getting smaller. Hereinafter, this hex nut is referred to as a standard hex nut.

  9A is a plan view showing a state in which the processing jig 6 of the first embodiment is arranged at a predetermined position with respect to the standard hexagon nut 15, and FIG. 9B is a sectional side view thereof. As shown in FIGS. 9 (a) and 9 (b), one end side of the outer periphery of the standard hexagon nut 15 is rounded, that is, the small diameter end portion side of the screw hole 15a is arranged on the upper side, The side surface of the standard hexagon nut 15 is pressed and fixed by a pair of holding jigs 16 and 16.

  The processing jig 6 of the first embodiment is disposed coaxially (centered) with the standard hexagon nut 15 above the standard hexagon nut 15. Then, the three protrusions 9 of the processing jig 6 are positioned so as to correspond to the three sides arranged every other side of the standard hexagon nut 15.

  As shown in FIG. 10, the processing jig 6 is moved closer to the standard hexagon nut 15 in the axial direction, and the pressing surfaces 10 of the three protrusions 9 are pressed against the outer peripheral surface on the upper end side of the standard hexagon nut 15. To do. By this press contact, the concave strip portion 2 having the inclined surface 3 is locally formed on each of the upper ends of the three flat surfaces disposed on the outer peripheral surface of the standard hexagon nut 15 every other surface. In addition, the upper end side of the screw hole 15a is diameter-reduced in combination with the formation of the recessed strip portion 2. In this way, the locking nut of the first embodiment shown in FIG. 1 is formed.

  Moreover, it is possible to reduce the diameter of the screw hole 15 a by pressing the outer peripheral surface on either end side of the standard hexagon nut 15 with the processing jig 6. However, as in the above embodiment, the screw hole 15a (one end side) can be efficiently reduced in diameter by pressing the outer peripheral surface corresponding to one end side of the screw hole 15a having a small diameter in advance. Moreover, it is possible to sufficiently ensure the insertion property and fastening force of the screw hole 15a with respect to the bolt. Furthermore, since the edge of the end portion where the screw hole 15a has a small diameter has a round outer peripheral edge, it is easy to determine which end portion of the screw hole 15a has a small diameter by visual observation or the like. Can be determined.

  Further, as the material of the locking nut of the present invention, two or three types of hexagon nuts having rounded edges at both ends among the hexagon nuts defined in JISB1181 are also applicable. Further, the retaining nut of the present invention can be manufactured even by using a machined hex nut, but the forged hex nut has a cost advantage.

Next, a method for manufacturing a locking nut using the processing jig of the second embodiment will be described.
FIG. 11A is a plan view showing a state in which the processing jig 60 of the second embodiment is arranged at a predetermined position with respect to the standard hexagon nut 15, and FIG. 11B is a sectional side view thereof. Also in the manufacturing method of the second embodiment, a standard hexagon nut similar to the above is used as the material of the locking nut. As shown in FIGS. 11 (a) and 11 (b), one end of the standard hexagon nut 15 is rounded, that is, the small diameter end of the screw hole 15a is disposed on the upper side. The side surface of the standard hexagon nut 15 is pressed and fixed by a pair of holding jigs 17 and 17.

  The processing jig 60 of the second embodiment is disposed coaxially (centered) with the standard hexagon nut 15 above the fixed standard hexagon nut 15. Then, the two pairs of rods 11 of the processing jig 60 are positioned so as to correspond to the two opposite sides of the standard hexagon nut 15.

  Then, as shown in FIG. 12, the processing jig 60 is moved closer to the standard hex nut 15 in the axial direction, and the outer peripheral surface of each rod 11 is pressed against the outer peripheral surface on the upper end side of the standard hex nut 15. By this pressure contact, the concave strip portion 4 having the inclined surface 5 is formed on each of the upper ends of the two flat surfaces facing the opposite sides of the outer peripheral surface of the standard hexagon nut 15. In addition, the upper end side of the screw hole 15a is diameter-reduced in combination with the formation of the concave strip portion 4. In this way, the locking nut of the second embodiment shown in FIG. 2 is formed. In the case of the second embodiment, the outer peripheral surface of the rod 11 serves as a pressing surface that presses the upper end side of the standard hexagon nut 15. Also, the reason why the outer peripheral surface corresponding to the one end side of the screw hole 15a that has a small diameter in advance is pressed is the same as in the case of the first embodiment, in which the screw hole 15a (one end side thereof) is efficiently provided. This is to reduce the diameter.

  The manufacturing method of pressing the three outer peripheral surfaces of the standard hexagon nut (see FIG. 9) is more effective than the manufacturing method of pressing the two outer peripheral surfaces of the standard hexagon nut (see FIG. 11). It is possible to uniformly reduce the diameter in a wide range across the direction. Moreover, when pressing 3 planes, there exists an advantage which is easy to center a processing jig with respect to a standard hexagon nut.

  On the other hand, the manufacturing method of pressing the two planes has an advantage that the holding jig for fixing the standard hexagon nut is less likely to interfere with the processing jig as compared with the method of pressing the three planes. As a result, the standard hexagon nut can be pressed in a wide range by the holding jig and stably fixed.

  Further, as shown in FIG. 13, for example, the axial length P of the outer peripheral surface of the standard hexagon nut 15 that forms the inclined surface 3 is about 3 minutes of the axial length Q of the standard hexagon nut 15. 1 is set. That is, in FIG. 13, the upper third region of the screw hole 15a is subjected to diameter reduction processing, and in this region, the bolt is strongly fastened. On the other hand, the lower two-third region of the screw hole 15a is a region in which the diameter reduction processing is not performed and the bolt insertion property is favorably maintained. The axial length P of the portion forming the inclined surface 3 is not limited to being set to about one third of the axial length Q of the standard hexagon nut 15.

  As described above, the method of manufacturing the locking nut according to the present invention can manufacture a standard hexagonal nut as a material, so that the conventional manufacturing method using the specially shaped nut shown in FIGS. 15 and 16 as a material is used. In comparison, it can be manufactured easily and inexpensively.

  By the way, when the standard hex nut is manufactured by forging or the like, the axial length of the standard hex nut varies. If a standard hexagonal nut having a variation in the axial length is used as a material for the locking nut, an error occurs in the amount of diameter reduction of the screw hole due to the variation in the axial length.

  However, according to the method for manufacturing a locking nut of the present invention, even if the standard hexagonal nut has variations in axial length, an error in the diameter reduction amount of the screw hole can be reduced. Hereinafter, this will be described in detail.

  When the processing jig of the present invention is attached to a drive device that moves up and down at a predetermined stroke, as shown in FIG. 14A, the pressing surface 10 (or rod 11) of the processing jig is Even if there is a variation ΔL in the axial length of the standard hexagon nuts 18a and 18b, the standard hexagon nut is lowered to a predetermined position and presses the outer peripheral surface on one end side of the standard hexagon nut. For this reason, the pressing amount S in the radial direction of the standard hexagon nut 18a indicated by the two-dot chain line is larger than the pressing amount T in the radial direction of the standard hexagon nut 18b indicated by the one-dot chain line. At this time, if the inclination angle of the pressing surface 10 (with respect to the axis of the standard hexagon nut) is γ, the difference (ST) between the two pressing amounts T and S is ΔL × tan γ. Therefore, when the inclination angle γ of the pressing surface 10 is set to be less than 45 °, tan γ <1, so that the difference in the pressing amount in the radial direction (ST), that is, the error in the diameter reduction amount of the screw hole is standard. It is possible to make it smaller than the variation ΔL in the axial length of the hexagon nut.

  On the other hand, the conventional method for manufacturing a locking nut shown in FIG. 18 uses a standard hex nut as a material, as in the manufacturing method of the present invention. It differs from the present invention in that it is pressed in the axial direction. In this conventional manufacturing method, as shown in FIG. 14 (b), when the end faces of the standard hexagon nuts 18a and 18b having variations ΔL in the axial length are pressed by the processing jig 19, A difference (U−V) between the pressing amounts U and V in the axial direction is the same as the variation ΔL. Therefore, in the conventional manufacturing method shown in FIG. 18, the error in the pressing amount cannot be made smaller than the variation ΔL in the axial length of the standard hexagon nut.

  Further, by changing the inclination angle γ of the pressing surface 10 of the processing jig shown in FIG. 6, the inclination angle α of the inclined surface 3 of the locking nut of the first embodiment shown in FIG. 2 can be adjusted. It is. Further, by changing the inclination angle δ of the rod 11 shown in FIG. 8, the inclination angle β of the inclined surface 5 of the locking nut of the second embodiment shown in FIG. 4 can be adjusted.

  Hereinafter, the reason why the lower limit value and the upper limit value of the inclination angles α, β, γ, and δ are set as described above will be described. The reason for setting the lower limit value and the upper limit value is the same for each inclination angle α, β, γ, δ. Therefore, the inclination angle α of the inclined surface 3 of the locking nut of the first embodiment is taken as an example. explain.

  When the inclination angle α is set to be less than the lower limit of 10 °, the screw hole may be reduced in diameter at the other end opposite to the one end where the inclined surface 3 of the standard hexagon nut 15 is formed. This makes it difficult to insert the bolt into the screw hole. On the other hand, by setting the inclination angle α to 10 ° or more, it is possible to maintain the insertion property of the bolt into the screw hole.

  When the inclination angle α exceeds the upper limit of 45 °, the amount of narrowing of the screw pitch increases, but the amount of diameter reduction of the screw hole cannot be obtained sufficiently. Even if the screw pitch is narrowed, the fastening force with the bolt can be improved. However, since the amount of elastic deformation of the screw pitch is small, once it is fastened to the bolt, the screw pitch is plastically deformed in the expanding direction and is not elastically restored. Therefore, when the bolt is next fastened, the loosening prevention function is remarkably lowered.

  On the other hand, by setting the inclination angle α to 45 ° or less, the amount of diameter reduction of the screw hole can be sufficiently secured. Since the amount of elastic deformation in the radial direction of the screw hole is large, even if the locking nut is repeatedly fastened to the bolt, the locking function can be maintained.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. . In the above-described embodiment, the processing jig is pressed close to the axial direction of the standard hexagon nut, but the processing jig is approached in an orthogonal direction or an oblique direction with respect to the axial direction of the standard hexagon nut. You may comprise so that it may press.

It is a perspective view which shows 1st Embodiment of the locking nut of this invention. It is a cross-sectional side view of the locking nut of FIG. It is a perspective view which shows 2nd Embodiment of the locking nut of this invention. It is a cross-sectional side view of the locking nut of FIG. It is a top view which shows 1st Embodiment of the jig for processing the locking nut of this invention. It is an AA cross section side view of the processing jig of the first embodiment shown in FIG. It is a top view which shows 2nd Embodiment of the jig for processing the locking nut of this invention. It is a BB cross-section side view of the processing jig of the second embodiment shown in FIG. It is a figure which shows the state which has arrange | positioned the processing jig of the said 1st Embodiment in the predetermined position with respect to the hexagon nut, Comprising: (a) is the top view, (b) is the cross-sectional side view. It is a cross-sectional side view which shows the state which pressed the hexagon nut with the processing jig of the said 1st Embodiment. It is a figure which shows the state which has arrange | positioned the processing jig of the said 2nd Embodiment in the predetermined position with respect to the hexagon nut, Comprising: (a) is the top view, (b) is the cross-sectional side view. It is a cross-sectional side view which shows the state which pressed the hexagon nut with the processing jig of the said 2nd Embodiment. It is the cross-sectional side view which showed an example of the axial direction length of the inclined surface with respect to the axial direction length of the locking nut of this invention. It is the schematic diagram which expanded the one end side of the locking nut, (a) is a figure of the locking nut of this invention, (b) is a figure of the conventional locking nut. It is a figure which shows one Example of the manufacturing method of the conventional locking nut. It is a figure which shows the other Example of the manufacturing method of the conventional locking nut. It is a figure which shows another Example of the manufacturing method of the conventional locking nut. It is a figure which shows another Example of the manufacturing method of the conventional locking nut.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nut main body 1a Screw hole 3 Inclined surface 5 Inclined surface 6 Machining jig 7 Jig main body 9 Protruding part 10 Pressing surface 11 Rod 15 Hex nut 15a Screw hole 60 Machining jig 70 Jig main body L axis X axis α inclination Angle β Tilt angle γ Tilt angle δ Tilt angle

Claims (9)

  By pressing the outer peripheral surface on one end side of the hexagon nut defined in JISB1181, an inclined surface inclined with respect to the axis is formed on the outer peripheral surface of the hexagon nut, whereby the screw of the hexagon nut corresponding to the inclined surface is formed. A locking nut having a reduced diameter at one end of the hole.   By pressing one end side of two planes facing opposite directions among the six planes constituting the outer peripheral surface of the hexagon nut, an inclined plane inclined with respect to the axis is formed on the two planes, thereby The locking nut according to claim 1, wherein one end side of the screw hole of the hexagon nut corresponding to the surface is reduced in diameter.   By pressing one end side of three planes arranged every other plane out of the six planes constituting the outer peripheral surface of the hexagon nut, an inclined plane inclined with respect to the axis is formed on the three planes. The loosening prevention nut according to claim 1, wherein the one end side of the screw hole of the hexagon nut corresponding to the inclined surface is reduced in diameter.   The loosening prevention according to any one of claims 1 to 3, wherein a lower limit value of an inclination angle of the inclined surface with respect to the axis of the hexagon nut is set to 10 °, and an upper limit value of the inclination angle is set to 45 °. nut.   The loosening prevention according to any one of claims 1 to 3, wherein a lower limit value of an inclination angle of the inclined surface with respect to an axis of the hexagon nut is set to 20 °, and an upper limit value of the inclination angle is set to 30 °. nut.   The pressing surface of the processing jig is brought into pressure contact with the outer peripheral surface on one end side of the hexagon nut defined in JISB1181 while being inclined with respect to the axis of the hexagon nut, and the inclined surface is formed on the outer peripheral surface on one end side of the hexagon nut. A method of manufacturing a locking nut, wherein the one end side of the screw hole of the hexagon nut corresponding to the inclined surface is subjected to diameter reduction processing by plastic processing.   The hexagon nut is forged by a die having a draft angle, so that the inner diameter on one end side of the screw hole becomes smaller than the other end, and the outer peripheral surface on the one end side of the hexagon nut is processed on the outer peripheral surface. The pressing surface of the jig is inclined with respect to the axis of the hexagon nut and is pressed, and the inclined surface is plastic-worked on the outer peripheral surface on one end side of the hexagon nut, so that the hexagon nut corresponding to the inclined surface is deformed. The method for manufacturing a locking nut according to claim 6, wherein one end side of the screw hole is reduced in diameter.   A protrusion having a pressing surface is provided on the jig main body, and the pressing surface is disposed so as to be capable of press contact with an outer peripheral surface on one end side of a hexagon nut defined in JISB1181 in an axial direction. Fixing nut processing jig.   The rod is detachably attached to the jig body, and the rod is disposed on the outer peripheral surface on one end side of the hexagonal nut defined in JISB1181 so as to be capable of being pressure-contacted while being inclined in the axial direction. Processing jigs.

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