JP2015078753A - Lock nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lock nut 10 capable of positively preventing looseness of a lock screw 17 without fixing looseness of a lock screw 17 acting as a weight member to be screwed into a balance adjusting thread hole 16 under application of adhesive agent.SOLUTION: This invention relates to a lock nut 10 comprising a plurality of balance adjustment thread holes 16 arranged in a circumferential direction at either an outer circumferential surface or an end surface of a nut main body 11 and lock screws 17 acting as weight members that are threadably fitted to the balance adjustment thread holes, fastening and fixing of the lock screws 17 against the balance adjustment thread holes 16 are carried out by plastic deformation of the balance adjustment thread holes 16 with the lock screws 17 to prevent the lock screws from being loosened.

Description

  The present invention relates to a lock nut for positioning and fixing a member to be fixed such as a bearing attached to a rotating shaft such as a main shaft that rotates at high speed such as a machine tool.

  Lock nuts are used to position and fix fixed members such as bearings attached to rotating shafts, such as spindles that rotate at high speed, such as machine tools, even if there is a gap between the tightening surface due to vibration or impact, A locking mechanism is provided so that loosening does not occur.

  As a lock nut of this type, as shown in FIG. 7, a cylindrical nut body 1 having a female screw portion 2 screwed to a male screw portion of a rotating shaft on the inner peripheral surface penetrates from the outer peripheral surface to the inner peripheral surface. A plurality of holes 3 are provided in the circumferential direction, a lock pin 4 is inserted into the through hole 3, the nut body 1 is screwed into the male screw portion of the rotating shaft, and then a push screw 5 is screwed into the through hole 3. There is one in which the nut body 2 is prevented from loosening by causing the front end of the lock pin 4 to be engaged with the male screw portion of the rotating shaft by the screw 5.

  Further, in a spindle rotating at high speed such as a machine tool, the rotation balance is adjusted in order to reduce the vibration of the spindle.

  As shown in FIG. 7, as the lock nut capable of adjusting the rotation balance, a plurality of balance adjusting screw holes 6 are provided at equal intervals in the circumferential direction on the outer peripheral surface or end surface of the nut body 1, and the main shaft is mounted on the balancing device. There is one in which the rotation balance is adjusted by screwing a set screw 7 as a weight member into the balance adjustment screw hole 6 at a required position while measuring the rotation balance of the main shaft (Patent Document 1).

JP 2009-281426 A

  However, the spindle rotates at a high speed, and the set screw 7 screwed into the balance adjusting screw hole 6 is loosened due to vibration and heat generated when a workpiece is machined by a tool attached to the tip of the spindle, thereby rotating the balance. May break down.

  In order to prevent the set screw 7 from loosening, if the set screw 7 is fixed with an adhesive or the like after the set screw 7 is screwed in, the rotational balance may be lost due to the weight of the adhesive or the like. The method of fixing 7 with an adhesive or the like cannot be applied to the adjustment of the rotational balance.

  Accordingly, an object of the present invention is to reliably prevent the set screw from loosening without fixing the set screw as a weight member screwed into the balance adjusting screw hole with an adhesive or the like.

  In order to solve the above-described problems, in the present invention, a cylindrical nut body having an internal thread surface on the inner peripheral surface that is threadedly engaged with an external thread portion of a rotating shaft having an external thread portion formed on the outer peripheral surface; A plurality of circumferentially arranged through holes penetrating from the outer peripheral surface to the inner peripheral surface, a lock pin inserted into the through hole, and screwed from the outer peripheral surface side of the through hole and inserted into the through hole A push screw that presses the lock pin toward the inner peripheral surface and engages the front end of the lock pin with the male screw portion of the rotary shaft, and a plurality of balance adjustment screws provided in the circumferential direction on the outer peripheral surface or end surface of the nut body In a lock nut comprising a hole, a screw hole for balance adjustment, and a set screw as a weight member screwed into the screw hole for balance adjustment, tightening and fixing the set screw to the screw hole for balance adjustment is stopped. It is characterized in that performed by plastic deformation of the balancing screw holes by screws.

  The plastic deformation of the balance adjusting screw hole is, for example, by providing a biting portion projecting on both sides in the axial direction on the top of the screw thread of the set screw, and biting the biting portion against the wall surface of the balance adjusting screw hole. Can be done.

  The biting portion at the top of the screw thread of the set screw can be provided at a diagonal position in the circumferential direction of the screw thread.

  The top of the screw thread of the set screw is formed on a flat surface, and a space is provided between the top of the screw thread of the set screw and the root of the screw thread of the screw hole for balance adjustment. By accommodating release powder generated when screwing into the screw hole for balance adjustment and preventing re-engagement of release powder when screwing the set screw, the set screw can be easily screwed.

  The bottom of the thread of the female screw part of the balance adjusting screw hole is made shallower than the height of the screw of the set screw, and the top of the screw of the set screw is bitten into the bottom of the screw hole for balancing. The adjustment screw hole may be plastically deformed.

  The bottom of the thread of the female screw part of the balance adjustment screw hole is formed at a depth that does not interfere with the screw thread of the set screw at a few pitches from the entrance side, and the depth of the valley root thereafter is set to the depth of the screw thread of the set screw. By forming it shallower than the height, the set screw can be easily inserted into the balance adjusting screw hole.

  By using a material for forming the balance adjusting screw hole having a lower hardness than that of the set screw forming material, plastic deformation of the balance adjusting screw hole is facilitated.

  By providing a black oxide coating or manganese phosphate coating on the surface of the set screw, the coefficient of friction with the balance adjusting screw hole is reduced when the set screw is tightened, and the set screw is adjusted to the balance adjusting screw hole. Screwing becomes easy.

  According to the present invention, the set screw as the weight member is fastened and fixed to the balance adjustment screw hole by plastic deformation of the balance adjustment screw hole by the set screw, so that the set screw screwed into the balance adjustment screw hole is loosened. Can be prevented.

It is a perspective view of a 1st embodiment of a lock nut concerning this invention. It is the front view which showed a part of embodiment of FIG. 1 in the cross section. It is a perspective view of 2nd Embodiment of the lock nut which concerns on this invention. (A) is a front view of a set screw used for a lock nut concerning this invention, and (b) is the sectional view. It is a fragmentary sectional view which shows the state which screws the set screw of FIG. 4 in the screw hole for balance adjustment of a lock nut. It is a fragmentary sectional view which shows the state which screws the set screw of another form used for the lock nut which concerns on this invention into the screw hole for balance adjustment of a lock nut. It is a perspective view of the conventional lock nut.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 and 2 show a lock nut according to a first embodiment of the present invention for positioning and fixing a fixed member such as a bearing attached to a rotary shaft such as a main shaft that rotates at high speed such as a machine tool. .

  This lock nut is provided with two through holes 13 in the circumferential direction penetrating from the outer peripheral surface to the inner peripheral surface in a cylindrical nut body 11 having an inner peripheral surface with a female screw portion 12 screwed with the male screw portion of the main shaft, After inserting the lock pin 14 into the through hole 13 and screwing the nut body 11 into the male threaded portion of the main shaft, a push screw 15 is screwed into the through hole 13, and the front end of the lock pin 14 is moved by the push screw 15 to the main shaft. The nut body 11 is prevented from loosening by being bitten by the male thread portion.

  The lock nut is provided with a plurality of balance adjustment screw holes 16 at equal intervals in the circumferential direction in the nut body 11, the main shaft is placed on the balancing device, and the balance adjustment screw at the required position is measured while measuring the rotation balance of the main shaft. The rotation balance can be adjusted by screwing a set screw 17 into the hole 16 as a weight member.

  In the lock nut of the first embodiment shown in FIGS. 1 and 2, six screw holes 16 for balance adjustment are arranged in the axial direction from the end face side of the nut body 1.

  In the lock nut of the second embodiment shown in FIG. 3, the lock nut is disposed at an angle of 45 degrees with respect to the axial direction of the balance adjusting screw hole 16.

  As in the second embodiment shown in FIG. 3, when the balance adjusting screw hole 16 is disposed at an angle, the balance adjusting operation can be performed from outside the main shaft using a jig. Further, when the balance adjusting screw hole 16 is disposed at an angle with respect to the axial direction, the set screw 17 as a weight member is provided as compared with the lock nut of the first embodiment shown in FIGS. Since the distance from the shaft center can be changed, the balance adjustment capability can be increased.

  When the balance adjusting screw hole 16 is disposed at an angle with respect to the axial direction, the angle is not limited to 45 degrees, and any angle can be adopted.

  The lock nut according to the first embodiment shown in FIGS. 1 and 2 and the lock nut according to the second embodiment shown in FIG. 3 are each used when a lock nut 10 is tightened on the outer peripheral surface of the nut body 11 (see FIG. (Not shown) is provided with an engaging groove 18.

  The lock nut according to the present invention is characterized by the fact that the set screw 17 as a weight member is fastened and fixed to the balance adjustment screw hole 16 by plastic deformation of the balance adjustment screw hole 16 by the set screw 17. The set screw 7 screwed into the screw hole 6 is not loosened.

  In the first embodiment shown in FIGS. 1 and 2 and the second embodiment shown in FIG. 3, when the set screw 17 is screwed into the balance adjusting screw hole 16, the set screw 17 becomes the balance adjusting screw hole. 16 so that the balance adjusting screw hole 16 is plastically deformed and the set screw 17 and the balance adjusting screw hole 16 are firmly tightened without loosening. The biting portion 19 is formed by squashing the top of the corner position into a trapezoid and projecting on both sides in the axial direction.

  When a set screw 17 having a bite portion 19 projecting on both sides in the axial direction is screwed into the balance adjusting screw hole 16 at the top of the screw thread, as shown in FIG. Both wall surfaces near the valley bottom of the screw thread of the portion are plastically deformed, and the biting portion 19 bites into the screw hole 16 for balance adjustment (light ink portion in FIG. 5).

  As shown in FIG. 5, since the top of the thread of the set screw 17 is crushed into a trapezoidal shape, the top of the thread of the trapezoidal set screw 17 and the thread of the female thread of the balance adjusting screw hole 16 are shown. A space 21 is formed between the bottom of the valley. When the biting portion 19 of the set screw 17 bites into the wall surface of the balance adjusting screw hole 16, even if the peeling powder 20 of the balance adjusting screw hole 16 is generated, the peeling powder 20 is accommodated in the space 21. . For this reason, when the set screw 17 is screwed into the balance adjusting screw hole 16, re-engagement of the peeling powder 20 does not easily occur, so that the set screw 17 can be easily screwed.

  By the way, the screw hole 16 for balance adjustment formed in the nut main body 11 can be formed by roll tapping. When the balance adjusting screw hole 16 is formed by roll tapping, a concave portion 22 is formed at the top of the thread of the female screw portion of the balance adjusting screw hole 16, and the peeling powder 20 is also accommodated in the concave portion 22. Can do.

  Next, in the third embodiment shown in FIG. 6, the thread bottom of the female screw portion of the balance adjustment screw hole 16 is shallow, and the thread of the set screw 17 is formed on the bottom of the balance adjustment screw hole 16. By biting the top, the valley bottom of the balance adjustment screw hole 16 is plastically deformed so that the set screw 17 and the balance adjustment screw hole 16 are firmly tightened without loosening (the bite in FIG. 6). The embedding part 19 is indicated by light ink).

  In the third embodiment shown in FIG. 6, the female screw portion of the balance adjusting screw hole 16 is formed at a depth that does not interfere with the screw thread of the set screw 17 from the entrance side, and the valley bottom after the third pitch is formed. It is shallow. By setting the entrance side to a depth that does not interfere with the threads of the set screw 17, the set screw 17 can be easily inserted into the balance adjusting screw hole 16.

  Further, the top of the thread of the female thread portion of the balance adjusting screw hole 16 of the third embodiment shown in FIG. 6 is removed, and the top of the thread of the female thread portion of the balance adjusting screw hole 16 and the screw of the set screw 17 are removed. A space 21 is formed between the bottom of the mountain. When the thread of the set screw 17 bites into the valley bottom of the balance adjustment screw hole 16, even if the release powder 20 of the balance adjustment screw hole 16 is generated, the release powder 20 is accommodated in the space 21. For this reason, when the set screw 17 is screwed into the balance adjusting screw hole 16, re-engagement of the peeling powder 20 is unlikely to occur, so that the set screw 17 can be easily screwed.

  In the first to third embodiments described above, the set screw 17 and the nut body 11 can be formed of an iron-based material, for example, JIS SS400, but the hardness of the nut body 11 that forms the screw hole 16 for balance adjustment. Is made lower than the hardness of the set screw 17 to facilitate plastic deformation of the balance adjusting screw hole 16.

  In addition, if a black oxide film or a manganese phosphate film is formed on the surface of the set screw 17 that plastically deforms the balance adjustment screw hole 16, when the set screw 17 is tightened, The coefficient of friction is reduced and fastening can be performed relatively easily.

11: Nut body 12: Female thread portion 13: Through hole 14: Lock pin 15: Push screw 16: Screw hole 17 for balance adjustment: Set screw 18: Engaging groove 19: Biting portion 20: Peeling powder 21: Space 22: Dent

Claims (8)

  A cylindrical nut body having an internal thread surface on the inner peripheral surface that engages with an external thread portion of a rotating shaft having an external thread portion formed on the outer peripheral surface, and an inner periphery from a plurality of outer peripheral surfaces disposed in the circumferential direction of the nut body A through-hole penetrating to the surface, a lock pin inserted into the through-hole, and screwed from the outer peripheral surface side of the through-hole to press the lock pin inserted into the through-hole toward the inner peripheral surface side, A push screw that allows the front end of the nut to engage with the male screw portion of the rotating shaft, a plurality of balance adjustment screw holes provided in the circumferential direction on the outer peripheral surface or end surface of the nut body, the balance adjustment screw hole, and the balance In a lock nut comprising a set screw as a weight member screwed into the adjustment screw hole, the fixing screw is fixed to the balance adjustment screw hole by means of a balance adjustment set screw. Lock nut, which comprises carrying out the plastic deformation.   The plastic deformation of the balance adjusting screw hole is provided with a biting portion protruding on both sides in the axial direction at the top of the set screw thread, and this biting portion is engaged with the wall surface of the balance adjusting screw hole. The lock nut according to claim 1, wherein the lock nut is performed.   The lock nut according to claim 2, wherein the biting portion of the top of the screw thread of the set screw is provided at a diagonal position in the circumferential direction of the screw thread.   The lock nut according to claim 2 or 3, wherein a top portion of a screw thread of the set screw is formed on a flat surface.   The bottom of the thread of the female screw part of the balance adjusting screw hole is made shallower than the height of the screw of the set screw, and the top of the screw of the set screw is bitten into the bottom of the screw hole for balancing. The lock nut according to claim 1, wherein the screw hole for adjustment is plastically deformed.   The bottom of the thread of the female screw part of the balance adjustment screw hole is formed at a depth that does not interfere with the screw thread of the set screw at a few pitches from the entrance side, and the depth of the valley root thereafter is set to the depth of the screw thread of the set screw. The lock nut according to claim 5, wherein the lock nut is formed shallower than the height.   The lock nut according to claim 1, wherein a material for forming the balance adjusting screw hole is lower in hardness than a material for forming a set screw. The lock nut according to claim 1, which has a black oxide film or a manganese phosphate film on a surface of the set screw.