JP6387506B2 - Screw body reverse rotation prevention structure - Google Patents

Description

  The present invention relates to a reverse rotation prevention structure for preventing reverse rotation of a fastened screw body.

  Conventionally, in various scenes, a screw body is used to fasten an object to be fastened. This screw body has a structure in which a male screw body in which a spiral groove is formed on a columnar outer periphery and a female screw body in which a spiral groove is formed on the inner periphery of a cylindrical member are screwed together.

  At the time of use, after inserting a male screw body into the hole formed in a to-be-fastened member, a female screw body is screwed together. As a result, the fastened object is sandwiched between the head of the male screw body and the cylindrical member of the female screw body. What is devised so that such a screw body for fastening can be used easily is a so-called bolt formed by forming a hexagonal column head at one end of the male screw member, and an outer peripheral surface formed in a hexagonal column shape. There are some combinations of nuts. In addition, a so-called small screw having a head portion that is not hexagonal and has a slit (minus hole) or a cross hole (plus hole) formed on the end face is also widely used.

  In addition, a washer (washer) is inserted around the male screw body when the screw body is fastened. This washer protects the object to be fastened from buckling or scratches at the time of fastening, and conversely suppresses loosening of the screw body by positively pressing the object to be fastened.

  For example, the washer has a general ring-shaped “flat washer” and a protrusion extending in the radial direction on the inner periphery and outer periphery, and is engaged with a member to be fastened or a screw body to prevent loosening. `` Washer with hook '', `` Washer with claw '' in which short claws bent in the axial direction engage with the object to be fastened, `` Spring washer '' to prevent loosening of the screw body by elastic deformation, teeth around the fastening surface There is a “toothed washer” and so on.

Japanese Industrial Standard JIS 1251 Spring Washer

  However, the conventional washer has a degree of expectation of friction and biting with respect to the structure for preventing loosening between the screw body, and the effect thereof is insufficient as well known. Therefore, in an environment where vibrations and the like are severe, there is a problem that even if a washer is used, the screw body gradually loosens.

  The present invention has been made by the inventor's diligent research in view of the above-mentioned problems, and by using a washer effectively, it has a simple structure and highly prevents reverse rotation of the screw body, that is, prevents loosening. It is an object to provide a structure for performing the following.

  The present invention for achieving the above object includes a screw body having a screw thread and a washer, and the screw body includes a screw body side seat portion facing the washer, and the washer includes the screw body side seat. A first receiving part facing the part, and a second receiving part facing the fastened member having a member side seat part, between the screw body side seat part and the first receiving part, A first engagement mechanism is configured that maintains a state of being engaged with each other even when a rotational force in a specific direction is applied to the screw body side seat portion, and the washer is disposed around the second receiving portion in the periphery of the screw A washer side abutting portion whose distance from the body axis is different along the circumferential direction, and the washer side abutting portion abuts and engages a part of the fastened body, thereby Second engagement in which the contact state is maintained even when the rotational force in the specific direction is applied. The first engagement mechanism prevents relative rotation in the specific direction between the screw body and the washer, and the second engagement mechanism allows the washer and the member to be fastened. The relative rotation in the specific direction between the screw body and the fastened member is prevented by preventing the relative rotation in the specific direction between the screw body and the reverse rotation of the screw body It is a prevention structure.

  In relation to the reverse rotation prevention structure of the screw body, the washer side contact portion is formed in a part of the circumferential direction of the screw body.

  In relation to the reverse rotation prevention structure of the screw body, the washer-side contact portion includes a first washer-side contact region facing one rotation direction of the screw body and the other rotation direction of the screw body. And an opposing second washer side contact area.

  In relation to the reverse rotation prevention structure of the screw body, the to-be-fastened member has a distance from the axis of the screw body that varies along a circumferential direction around the member side seat portion, and the washer side contact portion The member-side contact portion that can contact with the member, and the washer-side contact portion and the member-side contact portion are in contact with each other even if a rotational force in the specific direction acts on the washer The second engagement mechanism is configured to hold the screw member, and the second engagement mechanism prevents the screw member from rotating in the specific direction of the screw body.

  In relation to the reverse rotation prevention structure of the screw body, the member side contact portion is a first member side contact that is capable of contacting the washer side contact portion so as to face the other rotation direction of the screw body. And a second member-side contact region that can be in contact with the washer-side contact portion so as to face one rotation direction of the screw body.

  In relation to the reverse rotation preventing structure of the screw body, the washer-side contact portion extends along the axial direction of the screw body toward the washer side with respect to the fastened member. .

  In relation to the reverse rotation prevention structure of the screw body, the washer-side contact portion extends toward the fastened member side along the axial direction of the screw body with respect to the second receiving portion of the washer. It is characterized by doing.

  In relation to the reverse rotation prevention structure of the screw body, the member side contact portion is constituted by a cylindrical or cylindrical outer peripheral wall having a shaft different from that of the screw body.

  In relation to the reverse rotation prevention structure of the screw body, the first engagement mechanism includes a screw body side uneven portion formed on the screw body side seat portion and an engagement with the screw body side uneven portion on the first receiving portion. A first receiving portion side unevenness is formed to obtain the engagement state.

  In relation to the reverse rotation prevention structure of the screw body, the first receiving portion side unevenness is a saw blade shape provided in the circumferential direction.

  In relation to the reverse rotation prevention structure of the screw body, the screw body side seat portion is formed with a screw body side tapered surface inclined in the radial direction.

  In relation to the reverse rotation preventing structure of the screw body, the first receiving portion is formed with a washer-side tapered surface inclined in the radial direction.

  In relation to the reverse rotation prevention structure of the screw body, the first engagement mechanism is configured such that the engagement strength in the loosening direction increases as the distance between the screw body side seat portion and the first receiving portion decreases. It is characterized by being.

  In relation to the reverse rotation prevention structure of the screw body, the first engagement mechanism allows relative rotation in the tightening direction of the screw body side seat portion between the screw body side seat portion and the first receiving portion. It is characterized by that.

  In relation to the structure for preventing reverse rotation of the screw body, the outer wall of the second receiving portion has a circular shape eccentric with respect to the axis of the screw body.

  In relation to the reverse rotation prevention structure of the screw body, the member side contact portion includes a member side step portion stepped in the axial direction of the screw body around the member side seat portion, and the washer A washer-side step portion that engages with the member-side step portion is formed around the second receiving portion as the side contact portion.

  According to the present invention, the screw body can be reliably prevented from loosening by preventing the screw body from rotating backward, for example, by preventing the screw body from rotating in the direction in which the screw body is loosened. Become.

(A) is a side surface fragmentary sectional view which shows the reverse rotation prevention structure of the screw body of 1st embodiment of this invention, (B) is a top view. It is the side surface fragmentary sectional view and bottom view of the external thread body used with the reverse rotation prevention structure. It is the top view and side surface fragmentary sectional view of a washer used with the reverse rotation prevention structure. (A) is a conceptual diagram which shows the effect | action of the saw blade of the reverse rotation prevention structure of the screw body, (B)-(D) is a conceptual diagram which shows the modification of a saw blade. (A)-(C) are the conceptual diagrams which show the modification of the saw blade of the reverse rotation prevention structure. (A) (B) is a side view, without tightening the application example of the external thread body of the reverse rotation prevention structure. (A) and (B) are the top views and side surface fragmentary sectional views of the washer used by the application example of the reverse rotation prevention structure. (A) (B) is a top view which shows the example which applied the reverse rotation prevention structure to the fastening of a flange joint. (A) Top view and side partial cross-sectional view of washer, (B) Side partial cross-sectional view showing washer and male screw body, (C) shows the fastening state of the reverse rotation prevention structure of the screw body according to the second embodiment. It is side surface partial sectional drawing. (A) Top view and side partial sectional view of washer showing application examples of the reverse rotation prevention structure, (B) Side partial sectional view showing washer and male screw body, (C) is a side partial sectional view showing a fastening state. is there. It is a side surface fragmentary sectional view which shows the fastening state at the time of applying the reverse rotation prevention structure of the screw body of this invention to an internal thread body.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a reverse rotation prevention structure for a screw body according to the first embodiment. As shown in FIG. 3, the reverse rotation prevention structure of the screw body includes the male screw body 10, an annular washer 50, a fastened member 80, and a base 90. A female screw hole 92 for screwing with the male screw body 10 is formed in the base 90, and the fastened member 80 is fixed by being sandwiched between the base 90 and the male screw body 10.

  The male screw body 10 is a so-called bolt and has a head portion 20 and a shaft portion 30. A screw body side seat portion 22 is formed at a portion corresponding to a lower portion or a root of the head 20. The shaft portion 30 is formed with a cylindrical portion 30a and a screw portion 30b. Of course, the cylindrical portion 30a is not essential.

  A first receiving portion 60 is formed on one side of the washer 50 (upper side in FIG. 1A). The first receiving portion 60 faces the screw body side seat portion 22, and a first engagement mechanism A is configured between the two. In the first engagement mechanism A, when at least the screw body side seat portion 22 tries to rotate in the direction of loosening the male screw body 10 in the fastened state, the first receiving portion 60 and the screw body side seat portion 22 engage with each other, Relative rotation between the first receiving portion 60 and the screw body side seat portion 22 with respect to the rotation direction is prevented.

  A second receiving part 70 is formed on the other side of the washer 50 (the lower side in FIG. 1A). The first receiving part 70 faces the fastened member 80.

  In the fastened member 80, a member side seat portion 82 that faces the second receiving portion 70 of the washer 50 is formed. The second receiving portion 70 and the member side seat portion 82 are both annular planar regions, and are in contact with each other to play a role of transmitting the fastening force (axial force) of the male screw body 10 to the fastened member 80. That is, most of the axial force of the male screw body 10 is transmitted to the fastened member 80 via the washer 50.

  Further, the member side seat 82 of the fastened member 80 and the second receiving portion 70 of the washer 50 are held in contact with each other even if a rotational force is applied to the washer 50 in a specific direction. Thus, the second engagement mechanism B in which relative rotation is restricted is configured.

  As shown in FIG. 1B, the second engagement mechanism B includes a washer side contact portion 110 and a member side contact portion 120. The outer wall of the washer 50 has a partial arc shape concentric with the axial center of the screw, and the string is made into a washer-side contact portion 110 by cutting the remaining portion into a straight line shape like a string. ing. That is, when only the washer-side contact portion 110 is considered, the second receiving portion 70 is configured by a plane perpendicular to the radial direction and facing outward in the radial direction.

  On the other hand, the member-side abutting portion 120 is configured by a plane that is perpendicular to the radial direction and directed radially inward around the member-side seat portion 82. Therefore, the washer-side contact portion 110 and the member-side contact portion 120 face each other and contact each other.

  More specifically, the washer-side abutting portion 110 includes a first washer-side abutting region 110 </ b> X that opposes one rotational direction X of the male screw body 10 and a second washer-side abutment that opposes the other rotational direction Y of the male screw body 10. A contact area 110Y. The member-side abutting portion 120 is opposed to the other rotational direction Y of the male screw body 10, and can be in contact with the first washer-side abutting region 110 </ b> X and one of the male screw bodies 10. The second washer side abutment region 110X is provided so as to face the second washer side abutment region 110Y.

  For example, when the male screw body 10 is a right-hand thread, if the male screw body 10 is rotated in the Y direction in order to tighten the male screw body 10, the washer 50 tends to rotate relative to the member side seat 82 in the Y direction. As a result, the contact state between the first washer side contact region 110X and the first member side contact region 120Y is maintained, and the relative rotation thereof is suppressed. Similarly, when the male screw body 10 tries to loosen in the X direction, the washer 50 tends to rotate relative to the member side seat 82 in the X direction. As a result, the second washer side contact region 110Y. And the contact state of the second member side contact region 120X are maintained, and the relative rotation thereof is suppressed.

  The washer-side contact portion 110 and the member-side contact portion 120 are disposed in a partial angular range Q in the circumferential direction of the male screw body 10. If it is to be formed around the entire circumference, the structure of the washer-side contact portion 110 and the member-side contact portion 120 becomes complicated and the manufacturing cost increases, and further, it tends to interfere with the fastening operation of the male screw body 10. The angle range constituting the contact portion is preferably less than 180 degrees, and more desirably less than 120 degrees. In this embodiment, the washer side contact portion 110 and the member side contact portion 120 are disposed within an angle range of about 70 degrees. As a result, the remaining range of 290 degrees can open the periphery of the male screw body 10.

  Furthermore, in this embodiment, the washer side contact portion 110 and the member side contact portion 120 extend along the axial direction of the male screw body 10 toward the washer 50 side with respect to the member side seat portion 82 of the fastened member 80. Exist. As a result, the washer 50 can effectively utilize its outer peripheral surface as the washer-side contact portion 110.

  In addition, although the structure where the rotation of the washer 50 is also suppressed is illustrated here when the male screw body 10 rotates in both directions X and Y, the present invention is not limited to this. When at least the washer 50 tries to rotate in the loosening direction X together with the male screw body 10, the contact state between the second washer side contact region 110Y and the second member side contact region 120X is maintained, and the first direction relative to the rotation direction X is maintained. What is necessary is just to prevent the relative rotation of the two receiving parts 70 and the member side seat part 82. FIG.

  As described above, when the male screw body 10 tries to rotate in the loosening direction X by the action of the first engagement mechanism A and the second engagement mechanism B, the relative relationship between the male screw body 10 and the fastened member 80 is interposed by the washer 50. Rotation is regulated. As a result, the male screw body 10 is prevented from loosening. Further, even when the male screw body 10 rotates in the tightening direction Y, the second engagement mechanism B suppresses the swirling of the washer 50, and the engagement operation of the first engagement mechanism A can be appropriately exhibited. .

  As shown in FIG. 2, as the first engagement mechanism A, the screw body side uneven portion 24 is formed on the screw body side seat portion 22 of the male screw body 10. The screw body side unevenness 24 has a saw blade shape that is continuously provided in the circumferential direction. The direction in which each of the screw body side irregularities 24 extends, that is, the direction in which the ridge line extends is the radial direction of the male screw body 10. As a result, the screw body side unevenness 24 extends radially from the axis.

  Further, the threaded body side seat portion 22 is formed with a threaded body side tapered surface 26 inclined in the radial direction. The screw body-side tapered surface 26 is inclined so that the center side approaches the screw tip, and as a result, has a conical shape convex to the screw tip side. More preferably, the aforementioned threaded body side unevenness 24 is formed on the threaded body side tapered surface 26.

  As shown in FIG. 3, as the first engagement mechanism A, the first receiving portion 60 of the washer 50 is formed with a first receiving portion side unevenness 64 that engages with the screw body side unevenness 24. The 1st receiving part side unevenness | corrugation 64 becomes the saw blade shape provided in multiple numbers by the circumferential direction continuously. The direction in which each of the first receiving portion side irregularities 64 extends, that is, the direction in which the ridge line extends, is along the radial direction of the male screw body 10. As a result, the first receiving portion side unevenness 64 extends radially from the center of the through hole 52 of the washer 50.

  Further, preferably, the first receiving portion 60 is formed with a washer-side tapered surface 66 inclined in the radial direction. The washer-side tapered surface 66 has a mortar shape that is inclined so that the center side approaches the screw tip. As a result, a concave conical shape is formed on the screw tip side. On the washer-side tapered surface 66, the above-described first receiving portion-side irregularities 64 are formed.

  As a result, when the male screw body 10 is tightened, in the first engagement mechanism A, the screw body side tapered surface 26 of the screw body side seat portion 22 enters the recess of the washer side tapered surface 66 of the washer 50, and the screw body side unevenness 24. And the first receiving portion side unevenness 64 are engaged. As shown in FIG. 4 (A), when the male screw body 20 tries to rotate in the fastening direction Y, the inclined surfaces 24Y and 64Y come into contact with each other, and the distance between them is set in the axial direction. Allow relative sliding while narrowing. On the other hand, when the male screw body 20 tries to rotate in the loosening direction X, the vertical surfaces (surfaces with a strong inclination) 24X and 64X come into contact with each other to prevent relative movement between the two. In particular, in the first engagement mechanism A, as the distance between the screw body side seat portion 22 and the first receiving portion 60 decreases by tightening the male screw body 10, the engagement between the screw body side unevenness 24 and the first receiving portion side unevenness 64 becomes stronger. Thus, the engagement strength on the loosening direction X side is increased. Here, the inclination angle of the screw body side taper surface 26 and the inclination angle of the washer side taper surface 66 are made different from each other. In particular, the inclination angle from the axis of the washer side taper surface 66 is set to the axis of the screw body side taper surface 26. By setting it to be narrower than the inclination angle from, it is possible to tighten without rattling regardless of the pitch of the sawtooth formed on each tapered surface.

  Returning to FIG. 3, the outer wall 72 around the second receiving portion 70 of the washer 50 has a planar shape in a portion corresponding to the washer-side contact portion 110, and the distance from the screw shaft center is in the circumferential direction. Fluctuates along. Specifically, in the first washer side contact region 110X, the distances XA, XB, and XC increase along one rotational direction X of the male screw body 10. In the second washer side contact region 110Y, the distances YA, YB, and YC increase along one rotational direction Y of the male screw body 10. The portion excluding the washer-side contact portion 110 has a perfect circular shape with a constant distance from the screw shaft center.

  As shown in FIG. 1B, a step that protrudes toward the head of the male screw 10 is formed around the member-side seat portion 82 of the fastened member 80. A planar side wall facing the washer 50 side in the step corresponds to the member-side contact portion 120. The distance from the axial center of the screw also varies along the circumferential direction in the member-side contact portion 120. Specifically, distances X1, X2, and X3 of the first member-side contact region 120Y increase along one rotational direction X of the male screw body 10. In the second member-side contact region 120X, the distances Y1, Y2, and Y3 increase along one rotational direction Y of the male screw body 10. Note that the amount of variation is set to be the same for the washer-side contact portion 110 and the member-side contact portion 120 if a slight margin is ignored. Alternatively, it is preferable that the washer 50 be elastic or shaped so that the margin gap is filled by deformation in the direction perpendicular to the axis caused by axial compression caused by tightening of the washer 50 by the male screw 10.

  Therefore, when the second receiving portion 70 of the washer 50 and the member side seat portion 82 of the fastened member 80 are brought into contact with each other, the washer side contact portion 110 and the member side contact portion 120 come into contact with each other. In the state where the two are combined, the relative rotation in the circumferential direction of both is restricted. In other words, the washer side contact portion 110 and the member side contact portion 120 act as the second engagement mechanism B.

  As mentioned above, according to the reverse rotation prevention structure of the screw body of the first embodiment, the first engagement mechanism A is configured between the screw body side seat portion 22 and the first receiving portion 60 by interposing the washer 50. When the second engagement mechanism B is disposed around the member side seat portion 82 and the second receiving portion 70 and the male screw body 10 is about to be loosened, both the first engagement mechanism A and the second engagement mechanism B are restricted. By the action, the male screw body 10 is engaged with the fastened member 80 in the circumferential direction, and the reverse rotation, that is, the loosening is prevented. Therefore, even if vibration etc. arise, the fastening state which does not loosen at all can be obtained.

  Further, in the present embodiment, as the first engagement mechanism A, the screw body side unevenness 24 and the first receiving portion side unevenness 64 are formed in a saw blade shape in which a plurality of continuous in the circumferential direction, and as a so-called ratchet mechanism or one-way clutch mechanism Works. As a result, during the fastening operation, the screw body side unevenness 24 and the first receiving portion side unevenness 64 are allowed to move relative to each other to realize smooth relative rotation, while during the loosening operation, the screw body side unevenness 24 and the first receiving portion. The relative movement of the side irregularities 64 is completely restricted. As a result, workability at the time of fastening and subsequent locking can be rationally achieved.

  In the first embodiment, as the first engagement mechanism A, the screw body side seat portion 22 and the first receiving portion 60 are formed with the screw body side taper surface 26 and the washer side taper surface 66. The contact area can be increased. Further, the fastening force in the axial direction of the male screw body 10 also acts in the radial direction by the tapered surface. By pressing the taper surfaces of each other in the radial direction, centering can be carried out by self-excitation. As a result, the concentricity of the male screw body 10 and the washer 50 is increased, and the engagement accuracy between the screw body side unevenness 24 and the first receiving portion side unevenness 64 can be increased. It is also preferable to slightly increase the inclination of the convex screw body side tapered surface 26 and slightly decrease the inclination angle of the concave washer side tapered surface 66 so as to provide a small difference in angle. If it does in this way, a mutual taper surface can be made to contact | abut little by little toward the radial direction outer side from the center with the increase in clamping pressure.

  Furthermore, in the first embodiment, as the second engagement mechanism B, it is avoided that the shapes of the washer side contact portion 110 and the member side contact portion 120 are concentric with respect to the screw shaft center. Yes. In other words, the shapes of the washer-side contact portion 110 and the member-side contact portion 120 change along the circumferential direction in the distance from the screw axis. With this shape, once the washer-side contact portion 110 and the member-side contact portion 120 are in contact with each other, further relative rotation in the circumferential direction is restricted as long as the axes are aligned. In particular, the washer-side contact portion 110 and the member-side contact portion 120 are not formed over the entire circumference of the male screw body 10, but are formed partially in the circumferential direction. While making the shape processing of 80 extremely simple, the relative rotation of both can be prevented, and the periphery of the washer 50 and the screw body 10 can be widely opened.

  In the first embodiment, the case where the screw body side unevenness 24 and the first receiving portion side unevenness 64 have a saw blade shape is illustrated as the first engagement mechanism A, but the present invention is not limited to this. For example, as shown in FIG. 4B, the unevenness of each other can be a mountain shape (both are inclined surfaces). In this manner, when the male screw body 20 rotates in the loosening direction X, the inclined surfaces 24X and 64X tend to move relative to each other. The screw body side unevenness 24 and the first receiving portion side unevenness are along the inclined surface. 64 tries to leave. If this moving distance (separation angle α) is set larger than the lead angle of the male screw body 10, even if the male screw body 10 tries to loosen, the screw body side unevenness 24 and the first receiving part side unevenness 64 are more likely to be separated from each other. You will not be able to relax. In FIG. 4B, the irregularity of the isosceles triangle is illustrated. However, as shown in FIG. 4C, the angle of the inclined surfaces 24Y and 64Y that are in contact with each other at the time of fastening rotation is smaller than that at the time of loose rotation. It is also preferable to make the inclination angles of the inclined surfaces 24X and 64X in contact with each other gentle. In this way, the circumferential distance P between the inclined surfaces 24Y and 64Y that must be overcome during fastening rotation can be shortened, so that looseness (gap) after fastening can be reduced.

  Moreover, as an application of FIGS. 4A to 4C, as shown in FIG. 4D, corrugated irregularities with curved ridges and valleys are also preferable. Smooth operability can be obtained during fastening. Furthermore, in the first embodiment, the unevenness extending in the radial direction is illustrated, but it is also preferable to form a spiral (spiral) groove or mountain (unevenness) as shown in FIG. Further, as shown in FIG. 5B, even a groove or mountain (unevenness) extending linearly can be inclined so that the circumferential phase changes with respect to the radial direction of the screw. Further, as shown in FIG. 5C, it is also preferable to adopt a so-called embossed shape in which a plurality of fine irregularities are formed both in the circumferential direction and the radial direction (planar shape) of the screw.

  Further, unlike the first embodiment, the uneven shapes of the screw body side unevenness 24 and the first receiving portion side unevenness 64 are not necessarily matched (similar). For example, different shapes from the various shapes in FIGS. 4 and 5 can be selected and combined with each other.

  In the first embodiment, the case where the screw body side tapered surface 26 is convex and the washer side tapered surface 66 is concave is illustrated, but the present invention is not limited thereto. For example, as shown in FIG. 6 (A), the threaded body side tapered surface 26 can be formed into a planar shape, or can be formed into a concave shape as shown in FIG. 6 (B). The same applies to the washer-side tapered surface. Although not particularly illustrated, for example, if the elastic deformation of the washer 50 is effectively used, it is not necessary to match the inclination angles of the two tapered surfaces. Of course, a tapered surface may be formed on only one of the male screw body 10 or the washer 50. Furthermore, by making both the tapered surfaces convex or concave, the elastic deformation of the washer can be utilized to bring them into close contact. Further, in order to obtain the elasticity of the washer 50, the basic shape of the washer 50 is preferably a so-called spring washer shape or a disc spring shape in which a spiral shape is used.

  Further, as an application of the first embodiment, as shown in FIG. 7A, washer-side contact portions 110 are formed at a plurality of locations (here, two locations) around the second receiving portion 70 of the washer 50. You can also At this time, the member side contact portions 120 formed around the member side seat portion 82 are also formed at a plurality of locations. At this time, the first member side contact region 110Y and the second member side contact region 120X are similar to the first washer side contact region 110X and the second washer side contact region 110Y of the washer side contact portion 110. It does not have to be a shape. As in this application example, the member-side contact portion 120 can also be configured by a part of the outer peripheral surface of a column that is convex with respect to the washer-side contact portion 110. As a result, the first member side contact region 110Y and the second member side contact region 120X become curved planes that contact in a convex state toward the first washer side contact region 110X and the second washer side contact region 110Y. . Even in such a structure, the washer-side contact portion 110 and the member-side contact portion 120 are in contact with each other, and the relative rotation in the circumferential direction is restricted.

  Further, as shown in FIG. 7B, the outer wall of the washer 50 has a partial arc shape S that is concentric with the axial center of the screw, and a projection extending in the radial direction only in a part of the region. T can be formed. The projection T serves as a washer-side abutting portion 110, and one side surface of the projection T facing the one screw rotation direction X of the male screw body 10 serves as a first washer-side abutment region 110 X, and the other rotation direction Y of the male screw body 10. The other side surface that faces the second washer side contact region 110Y. At this time, a pair of columnar protrusions K1 and K2 are formed around the member side seat 82 so as to sandwich the protrusion T. The protrusions K1 and K2 serve as the member side contact portion 120. One protrusion K1 is formed with a first member-side contact area 110Y that contacts the first washer-side contact area 110X, and the other protrusion K2 is in contact with the second washer-side contact area 110Y. A second member side contact region 120X is formed. Although not particularly illustrated, the protrusions K1, K2, and the like that become the member-side contact portion 120 may be detachable from the fastening member 80 by a screw structure or the like.

  FIG. 8A illustrates a state in which the structure of the first embodiment is applied to fastening a so-called flange joint. Here, a part of the outer peripheral surface of the pipe member 150 of the flange joint is used as the member-side contact portion 120 of the second engagement mechanism B. On the other hand, the washer 50 applied to the screw body 10 such as a bolt or a nut is formed with a washer side abutting portion 110 that abuts the outer peripheral surface of the tube member 150. The washer-side contact portion 110 has a planar shape that is perpendicular to the radial direction of the tube member 150, and this is brought into contact with the outer peripheral surface of the tube member 150, thereby restricting bidirectional rotation of the washer 50. .

  In addition, you may make it the shape of the washer side contact part 110 formed in the washer 50 as FIG. 8 (B) shows. Specifically, when the screw body 10 rotates in the tightening direction Y, the first washer side contact region 110X contacts the outer peripheral surface (second member side contact region 120Y) of the tube member 150, and the screw When the body 10 rotates in the loosening direction X, the second washer side contact region 110Y may contact the outer periphery of the adjacent washer 50 (first member side contact region 120X). That is, the adjacent washer 50 functions as the member side contact portion 120 of the second engagement mechanism B. If it does in this way, if the flange joint is fastened in the aspect of FIG. 8 (B) using the screw body 10 and the washer 50, the reverse rotation prevention structure of the screw body of this invention will be completed as a result. become. This concept is not limited to the fastening of flange joints, and can be applied when arranging a plurality of screw body reverse rotation prevention structures in parallel.

  FIG. 9 shows a reverse rotation prevention structure for a screw according to the second embodiment. As shown in FIG. 9B, the screw body side seat portion 22 of the male screw body 10 has a planar shape, and a saw blade-shaped screw body side unevenness 24 is formed there. Further, a constriction 32 for holding the washer 50 is formed at the root of the shaft portion 30 of the male screw body 10.

  As shown in FIG. 9A, the first receiving portion 60 of the washer 50 has a planar shape, and a saw blade-shaped first receiving portion side unevenness 64 is formed there. In the through hole 52 of the washer 50, an engagement protrusion 52 </ b> A that protrudes toward the inner peripheral side is formed, and is engaged with the constriction 32 of the male screw body 10. As a result, the male screw body 10 and the washer 50 can be integrated (coupled) in advance.

  Further, a washer side step 74 extending in the axial direction of the screw is formed around the second receiving portion 70 of the washer 50. Here, the washer-side stepped portion 74 is constituted by the inner wall of the claw bent toward the fastened member 80 with reference to the second receiving portion 70 of the washer 50.

  On the other hand, the member side seat portion 82 of the fastened member 80 has a member side step portion 82A extending in the axial direction of the screw. The member-side stepped portion 82A is a step that falls to the screw tip side. The distances from the screw shaft center of the washer side step 74 and the member side step 82A coincide with each other. Therefore, as shown in FIG. 9C, when the male screw body 10 is tightened, the washer side stepped portion 74 and the member side stepped portion 82A are engaged, and the relative rotation of the washer 50 and the fastened member 80 is prevented. The In other words, the washer side step 74 corresponds to the washer side contact portion 110 in the second engagement mechanism B, and the member side step 82A corresponds to the member side contact portion 120 in the second engagement mechanism B. .

  In this way, the second engagement mechanism B is in a partial range in the circumferential direction of the screw body 10 and further formed on the screw tip side as compared with the washer 50, so that the periphery of the screw body 10 is formed. It can be opened.

  In the second embodiment, the case where the two are integrated in advance by the constriction 32 of the male screw body 10 and the engaging protrusion 52A of the washer 50 is exemplified, but the method is not limited to this. For example, the male screw body 10 and the washer 50 can be integrated by magnetic force by giving magnetism to at least one of them. In addition, the male screw body 10 and the washer 50 can be integrated in advance by an adhesive, (spot) welding, or press-fitting (frictional force). It is also possible to integrate the male screw body 10 and the washer 50 using an auxiliary tool such as an O-ring.

  An application example of the second embodiment will be described with reference to FIG. Here, the fastened member 80 has a cylindrical shape that accommodates the shaft portion 30 therein, and plate-shaped ribs 89 extending in all directions are arranged around the periphery in order to increase the strength. The rib 89 is utilized as the member side contact portion 120 of the second engagement mechanism B. An annular washer side stepped portion 74 extending in the axial direction of the screw is formed around the second receiving portion 70 of the washer 50, and this washer side stepped portion 74 covers the cylindrical member to be fastened 80. . The washer side step 74 is formed with a notch 75 for avoiding interference with the rib 89.

  The inner peripheral surface of the notch 75 corresponds to the washer side contact portion 110, and the side surface of the rib 89 serves as the member side contact portion 120. When both contact | abut, it functions as the 2nd engagement mechanism B, As a result, the relative rotation of the washer 50 is suppressed.

  9 and 10 exemplify the case where the washer side stepped portion 74 is formed on the outer periphery of the washer 50, the present invention is not limited to this.

  In the first or second embodiment, the case where the head of the male screw body 10 and the washer 50 are engaged is illustrated. However, the present invention is not limited to the case of applying to the male screw body, and this locking mechanism is applied to the female screw body side. You can also For example, as shown in FIG. 11, the female screw body 18, the washer 50, and the fastened member 80 are provided with the first engagement mechanism A and the second engagement mechanism B, thereby preventing reverse rotation of the female screw body 18. Things are also possible.

  In the first or second embodiment, the washer 50 is exemplified only when the outer shape of the washer 50 is a circle, a partial arc, a string, or the like, but other shapes can be employed. For example, the outer shape of the washer 50 may be oval, oval, polygonal or the like. It is also preferable that the outer shape of the washer 50 is a circular shape that is eccentric with respect to the axis of the screw body. In other words, the outer shape of the washer 50 with respect to the axial center may be “non-perfect circle (not a concentric perfect circle)”.

  Further, the embodiments of the present invention are not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the scope of the present invention.

  According to the present invention, it is possible to reliably prevent screws from loosening with a simple structure.

DESCRIPTION OF SYMBOLS 10 Male screw body 20 Head part 22 Screw body side seat part 24 Screw body side uneven | corrugated 23 Press surface 26 Screw body side taper surface 30 Shaft part 30a Cylindrical part 30b Screw part 50 Washer 52 Through-hole 52A Engagement protrusion 60 First receiving part 64 First receiving part Part side unevenness 70 Second receiving part 72 Outer wall 74 Washer side step part 80 Fastened member 82 Member side seat part 89 Rib 90 Base 92 Female screw hole 110 Washer side contact part 110X First washer side contact area 110Y Second washer Side contact region 1120 Member side contact portion 110X Second member side contact region 110Y First member side contact region

Claims (14)

A screw body having a thread and a washer;
The screw body has a screw body side seat portion facing the washer,
The washer includes a first receiving portion facing the screw body side seat portion, and a second receiving portion facing a fastened member having a member side seat portion in advance .
A first engagement mechanism is configured between the screw body side seat portion and the first receiving portion so that the screw body side seat portion is maintained in an engaged state even when a rotational force in a specific direction acts on the screw body side seat portion. And
The washer has a washer-side contact portion around the second receiving portion, the distance from the axis of the screw body being different along the circumferential direction,
The to-be-fastened member is radially outward from the screw body side seat portion and at a place independent of its own screw hole, the distance from the axis of the screw body is different along the circumferential direction, and the washer side contact A member side contact portion that can contact the portion,
The washer-side abutting portion abuts on and engages with the member-side abutting portion of the fastened member , so that even when a rotational force in the specific direction acts on the washer, the abutting state of each other is obtained. A second engagement mechanism to be held is configured;
Relative rotation in the specific direction between the screw body and the washer is prevented by the first engagement mechanism, and the second engagement mechanism prevents the relative rotation between the washer and the member to be fastened. By preventing relative rotation in a specific direction, relative rotation in the specific direction between the screw body and the fastened member is prevented,
Screw body reverse rotation prevention structure. The washer-side contact portion is a flat surface formed in a part of the circumferential direction of the screw body,
The structure for preventing reverse rotation of the screw body according to claim 1. The washer-side abutting portion includes a first washer-side abutting region facing the one rotation direction of the screw body and a second washer-side abutting region facing the other rotation direction of the screw body. It is characterized by
The structure for preventing reverse rotation of the screw body according to claim 1 or 2. The member side contact portion is opposed to the first member side contact region capable of contacting the washer side contact portion while facing the other rotation direction of the screw body, and opposed to one rotation direction of the screw body. And a second member side contact area capable of contacting with the washer side contact portion,
The structure for preventing reverse rotation of the screw body according to any one of claims 1 to 3 . The washer abutting portion along the axial direction of the screw body, which extend in the washer side the workpieces basis,
The member-side contact portion of the fastened member is a surface that stands on the washer side around the screw hole,
It is characterized by
The structure for preventing reverse rotation of the screw body according to any one of claims 1 to 4 . The washer side abutting portion extends along the axial direction of the screw body toward the fastened member side with respect to the second receiving portion of the washer.
The structure for preventing reverse rotation of the screw body according to any one of claims 1 to 4 . The member-side abutting portion is constituted by a cylindrical or cylindrical outer peripheral wall that is positioned radially outward from the screw body side seat by making the screw body and the shaft different from each other.
The structure for preventing reverse rotation of the screw body according to claim 4 . In the first engagement mechanism, a screw body side unevenness is formed on the screw body side seat portion, and a first receiving portion side unevenness engaging with the screw body side unevenness is formed on the first receiving portion, and the engagement Characterized by getting state,
The structure for preventing reverse rotation of the screw body according to any one of claims 1 to 7 . The first receiving part side unevenness is a saw blade shape provided in the circumferential direction,
The structure for preventing reverse rotation of the screw body according to claim 8 . In the screw body side seat portion, a screw body side tapered surface inclined in a radial direction is formed,
The reverse rotation prevention structure for a screw body according to any one of claims 1 to 9 . The first receiving portion is formed with a washer side tapered surface inclined in the radial direction.
The structure for preventing reverse rotation of the screw body according to any one of claims 1 to 10 . The first engagement mechanism is configured to increase the engagement strength in the loosening direction as the distance between the screw body side seat portion and the first receiving portion decreases.
The reverse rotation prevention structure for a screw body according to any one of claims 1 to 11 . The first engagement mechanism allows relative rotation in the tightening direction of the screw body side seat portion between the screw body side seat portion and the first receiving portion.
The structure for preventing reverse rotation of the screw body according to any one of claims 1 to 12 .   The member side contact portion is a plate-like rib extending in the radial direction around the screw hole,
  The structure for preventing reverse rotation of the screw body according to any one of claims 1 to 13.

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