JPH0738733U - Cam washer - Google Patents

Abstract

(57) [Summary] [Purpose] In a cam washer that prevents loosening of a nut or a bolt, this fastening can be released after the nut or the bolt is fastened. [Structure] An outer peripheral portion 12A of the second washer 12 has a hexagonal shape, a slip stopper is formed on a surface of the second washer 12 that is in contact with an object to be fastened, and the first washer 11 is fitted into a recess 15 provided on the opposite surface. After the nuts are fastened, the washers 11 and 12 are integrally rotatably engaged by the cam portions 14 and 16 formed on the washers 11 and 12, and the slip stopper 13 is formed on the surface of the first washer 11 in contact with the nut. When the wrench is fitted to the second washer 12 and rotated in the direction of loosening the screw, both washers 11 and 12 and the nut rotate together.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cam washer, and more particularly, to a cam washer that locks a bolt or nut after fastening an object to be fastened with the bolt and nut.

[0002]

[Prior art]

 When the object to be fastened is fastened with bolts or nuts, if loosening occurs due to vibration or other external force after the fastening, the predetermined tightening axial force is lost and fastening failure occurs. Therefore, it is fastened by a combination of a nut that has a cam portion that has a downward slope in the screw tightening direction and is formed in an annular direction, and a cam washer that has a cam portion that engages with the nut-side cam portion on the top surface. Is considered to do.

According to such a combination structure, if the inclination angle of each of the cam portions is set to be larger than the lead angle of the screw portion of the nut, the nut is tightened in the halt to fasten the object to be fastened. In this state, even if the nut tries to rotate in the loosening direction due to subsequent vibration or other external force, the rotation must be such that the cam portion on the nut side moves over the cam washer cam portion to get over it. Since this does not happen, this rotation is blocked and loosening does not occur.

[0004]

[Problems to be solved by the device]

 By the way, when the nut and cam washer are used for fastening, once the fastening is done, the nut cannot be rotated in the loosening direction with respect to the bolt for the same reason as the anti-loosening action described above. Since it cannot be disassembled, there are some cases where the range of use is limited.

Therefore, an object of the present invention is to provide a cam washer capable of easily releasing the fastening when necessary while preventing loosening.

[0006]

[Means for Solving the Problems]

 That is, the device according to claim 1 of the present invention (hereinafter, referred to as the first device) is provided with a bolt or a nut formed in an annular direction with a cam portion having a downward slope in the screw tightening direction protruding on one surface. A cam washer to be used, the outer periphery of which is polygonal, and one side of which has a non-slip surface, and the other side of which has a plurality of cam portions which engage with the cam portions of the bolts or nuts in an annular direction. It is characterized in that the inclination angle of the cam portions is larger than the lead angle of the screw portion of the bolt or nut.

Further, a device according to claim 2 (hereinafter, referred to as a second device) is sandwiched between a first washer that contacts a bolt or a nut and the first washer and an object to be fastened. A cam washer comprising a second washer, wherein the outer peripheral portion of the second washer has a polygonal shape, a slip stopper is formed on one surface, and a concave portion is formed on the other surface. The first washer is fitted in such a manner that it can rotate and is prevented from coming out, and a slip stopper is formed on the surface of the first washer that contacts the above-mentioned bolt or nut, and a downward slope in the screw tightening direction on the opposite surface. The cam portion that protrudes is formed in an annular direction, and a plurality of cam portions that engage with the cam portion of the first washer are provided in the annular surface on the bottom surface of the recess, and the inclination angles of these cam portions are increased. Is the lead of the thread part of the above bolt or nut. Characterized by being larger than the corner.

[0008]

[Action]

 According to the first aspect of the invention, the engagement of the cam portion of the cam washer and the cam portion of the bolt or nut can prevent the bolt or nut from loosening due to vibration or the like while the bolt or nut is fastened. However, since the outer circumference of the cam washer has a polygonal shape, if the cam washer is grasped and rotated with a torque wrench after the above fastening, the bolt or nut will rotate with the cam washer. Now you can loosen the bolt or nut to disassemble.

Further, according to the second aspect, when the bolts or nuts are fastened, the engagement of the cam portions of both the first washer and the second washer causes vibration of the bolts or nuts due to vibration or the like. Although the outer circumference of the second washer is polygonal, the first washer will rotate together if the second washer is gripped and rotated with a torque wrench after the above fastening. In addition, the bolts or nuts also rotate together to prevent slippage provided on the first washer, and the bolts or nuts can be loosened and disassembled.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

In the first embodiment shown in FIGS. 1 to 3, a plurality of cam portions 2 and 2 having a downward slope in the screw tightening direction are formed on the lower surface of the nut 1 in an annular direction. On the other hand, in the cam washer 3, the outer peripheral portion 3A has a hexagonal shape, and the same number of cam portions 4 to 4 having a downward slope in the screw tightening direction are formed on the upper surface as well as the above-mentioned cam portion 2 and the lower surface is protruded. Non-slip 5 to 5 are provided. In that case, the inclination angles of the cam portions 2 and 4 of the nut 1 and the cam washer 3 are set to be larger than the lead angle of the screw portion of the nut 1.

As shown in FIG. 3, when the nut 1 and the cam washer 3 are fastened to the bolts 7 passed through the objects to be fastened X, X, the nut 1 is loosened by vibration or other external force after the fastening is completed. Even if an attempt is made to rotate in the directional direction, the rotation must cause the cam portions 2 to 2 on the nut 1 side to move over the cam portions 4 to 4 of the cam washer 3 in the direction of the arrow, and to overcome the movement. Moreover, since the inclination angle of each of the cam portions 2 and 4 is set to be larger than the lead angle of the screw portion 8 of the nut 1 and the bolt 7, this rotation is blocked and loosening does not occur.

Further, since the outer peripheral portion 3A of the cam washer 3 has a hexagonal shape, the cam washer 3 is rotated by fitting the wrench from the state where the nut 1 and the bolt 7 are fastened as described above. Can be made. Therefore, if the cam washer 3 is rotated in the direction to loosen the nut 10, the force acts on the nut 1 via the cam portions 2 and 4 in the engaged state, and the cam washer 3 rotates together with the nut. Since the nut 1 is loosened and the nut 1 can be subsequently rotated to remove it from the bolt 7, even if the nut itself cannot be directly rotated after fastening because the cam engagement structure is adopted for the purpose of preventing loosening, The nut 1 can be disassembled, and the objects to be fastened X, X can be disassembled.

FIG. 4 to FIG. 8 show a second embodiment of the present invention, in which the nut 10 without the cam portion as in the first embodiment is prevented from loosening and can be disassembled after fastening. It is a thing.

That is, the cam washer of this embodiment is composed of the first and second washers 11 and 12. The first washer 11 has a plurality of protrusion-shaped slip stoppers 13 to 13 formed on the upper surface with which the nut 10 contacts, and a plurality of cam portions 14 to 14 having a downward slope in the screw tightening direction project on the lower surface to form an annular shape. Formed in the direction. On the other hand, in the second washer 12, the outer peripheral portion 12A has a hexagonal shape, and the concave portion 15 into which the first washer 11 is fitted is formed in the central portion of the upper surface, and the screw tightening direction is formed on the bottom surface of the concave portion 15. The cam portions 16 having a downward slope are formed in the annular direction so as to project by the same number as the above-mentioned cam portions, and projecting cleat 17 to 17 are provided on the lower surface of the washer. In that case, the inclination angles of the cam portions 14 and 16 of the first and second washers 11 and 12 are set to be larger than the lead angles of the screw portions of the nut 10, and the second washer 12 has the above-mentioned configuration. The first washer 11 is fitted into the recess 15 with the cam portions 14 and 16 of both washers 11 and 12 engaged. Further, the caulking process is applied to the upper surface of the annular convex portion 18 surrounding the concave portion 15 of the second washer 12 in the state where the first washer 11 is fitted in this manner at approximately three places, and the caulking portions 19 to 19 (see FIG. 4) prevents the first washer 11 from slipping out. The first washer 11 can rotate in the recess 15 and can move up and down to some extent. The nut 10 is not in contact with the annular protrusion 18 of the second washer 12.

When the nut 10 is fastened to the bolt 7 using the cam washers 11 and 12 as shown in FIG. 8, the nut 10 is rotated in the loosening direction by vibration or other external force after the fastening is completed. Attempting to do so, the first washer 11 tries to rotate together with the nut 10 because the first washer 11 is fixed to the nut 10 by the anti-slip 13 provided on the upper surface. However, this rotation must be accompanied by the movement of the cam portion 14 on the side of the first washer 11 over the cam portion 16 of the second washer 12 fixed to the object X to be fastened by the cleat 17. Moreover, since the inclination angles of the cam portions 14 and 16 are set to be larger than the lead angles of the nut 10 and the screw portion 8 of the bolt 7, rotation is blocked and loosening does not occur.

Since the outer peripheral portion 12A of the second washer 12 has a hexagonal shape, a wrench is fitted to the second washer 12 from the state where the nut 10 is fastened to the bolt 7 as described above. It can be rotated. Therefore, when the second washer 12 is rotated in the direction of loosening the nut 10 against the anti-slip 17, the force acts on the first washer 11 via the cam portions 14, 16 in the engaged state. At the same time, it also acts on the nut 10 via the anti-slip 13, so that the nut 10 rotates together with the washers 11 and 12, and the nut 10 loosens. It can be removed. Therefore, the bolt 7 and the nut 10 can be disassembled and the objects X, X to be fastened can be disassembled even if the nut itself cannot be directly rotated after fastening because the cam engagement structure is adopted for the purpose of preventing loosening.

In the case of the second embodiment, two washers are used. Since the first washer is attached to the second washer 12 by the caulking portion 19 formed on the second washer, In the case where both washers 11 and 12 are separated, it is possible to save the trouble of combining them when using, and to avoid a situation where one of the washers is lost.

By the way, as described above, fastening with bolts and nuts is performed by rotating these bolts and nuts with a torque wrench or the like so that a predetermined tightening axial force can be obtained. Even if it is rotated, the specified tightening axial force may not always be obtained depending on the presence of screws, seat dents, rust, oil adhesion, etc., and it is difficult to determine that axial force, and multiple bolts, etc. There was a problem that the tightening axial force was not constant due to variations in the tightening rotation angle from the tightened state to the completion of tightening.

Therefore, in the second embodiment, a concave step portion 20 is formed by a notch at the outer peripheral corner of the seating surface side of the nut 10, and the C-shaped ring 21 having an opening portion 21A in the concave step portion 20 is formed. Are partially engaged with each other so as to project outward. In this case, the C-shaped ring 21 is, for example, a metal body (may be a resin body) having elasticity capable of expanding and contracting in the diameter direction, and is elastically fitted to the concave step portion 20 in the above-mentioned engaged state. , The nut 10 rotates integrally with the nut 10.

The second washer 12 has a size such that an annular convex portion 18 surrounding the concave portion 15 is located outside the C-shaped ring 21, and a temporary tightening position is provided on the upper surface of the annular convex portion 18. The position display mark (snag point or seating point) 22 and the fastening completion position display mark 23 are provided at a predetermined rotation angle. The marks 22 and 23 are formed by applying paint or engraving the washer 12.

According to the nut 10 and the cam washers 11 and 12, when the nut 10 is screwed into the bolt 7 with a wrench, the screwing proceeds and the second washer 12 is pressed against the surface of the object to be fastened, so that the cleat 17 can be prevented. When the screwing resistance of the nut 10 increases by biting into the object X, the screwing is stopped once, the diameter of the C-shaped ring 21 is expanded using the opening 21A, and the C-shaped ring 21 is rotated independently with respect to the nut 10. The opening 21A can be aligned with the temporary tightening position display mark 22, and then the nut 10 can be tightened by the wrench until the opening 21A is aligned with the fastening completion position display mark 23.

Therefore, according to the nut 10 and the cam washers 11 and 12, the angle between the temporary tightening position display mark 22 and the fastening completion position display mark 23 is set to a predetermined value when the nut 10 is tightened from the temporarily tightened state. If you set it so that the tightening axial force can be obtained easily and reliably, the specified tightening axial force will be obtained, and the tightening rotation angle from the temporary tightening state to the completion of tightening will be constant. , The variation of tightening rotation angle will not occur.

In each of the above embodiments, the cam washer used on the nut side has been described, but it goes without saying that the present invention can be applied to a cam washer for bolts. Further, the above-mentioned C-shaped ring may be a complete annular elastic ring, in which case a rotation angle indicating mark corresponding to the opening 21A is formed on the elastic ring.

[0025]

[Effect of device]

 As is clear from the above description, according to the first aspect of the present invention, the engagement of the cam portion of the cam washer and the cam portion of the bolt or nut prevents loosening of the bolt or nut due to vibration after fastening. Although it can be done, the outer periphery of the cam washer has a polygonal shape, so after the above fastening, if you grasp the cam washer with a torque wrench and rotate it, the bolt or nut will rotate with the cam washer. Then, the bolt or nut can be loosened and disassembled, and the object to be fastened can be disassembled and the bolt or nut can be reused.

Further, according to the second invention, since the outer peripheral portion of the second washer has a polygonal shape, if the second washer is gripped and rotated by a torque wrench or the like after the fastening, the first washer will be The bolt or nut rotates together with the first washer to prevent slippage, so that the bolt or nut can be loosened and disassembled. Alternatively, the nut can be reused. According to the second consideration, bolts and nuts having a normal shape without a cam portion can be used.

[Brief description of drawings]

FIG. 1 is a perspective view of a cam washer according to a first embodiment of the present invention.

FIG. 2 is a half sectional view of the cam washer.

FIG. 3 is a usage state diagram of the cam washer.

FIG. 4 is a plan view of a cam washer according to a second embodiment.

FIG. 5 is an exploded view of a cam washer of the second embodiment.

FIG. 6 is a partially cutaway side view of the cam washer of the second embodiment.

FIG. 7 is a plan view showing a usage state of a cam washer of the second embodiment.

FIG. 8 is a side view of FIG. 7.

[Explanation of symbols]

 1,10 Nut 2,4 Cam part 3 Cam washer 5 Anti-slip 11 First washer 12 Second washer 13,17 Anti-slip 14,16 Cam part 15 Recess

Claims (2)

[Scope of utility model registration request] 1. A cam washer for use with a bolt or a nut, which is formed in an annular direction so that a cam portion having a downward slope in the screw tightening direction on one surface is projected, and the outer peripheral portion has a polygonal shape. A plurality of cam portions that engage with the cam portions of the bolts or nuts are provided on the other surface in an annular direction on the other surface, and the inclination angle of these cam portions is the screw portion of the bolts or nuts. Cam washer characterized by being made larger than the lead angle of. 2. A first washer in contact with a bolt or a nut, and a second washer sandwiched between the first washer and the object to be fastened.
The washer is a cam washer, and the outer peripheral portion of the second washer has a polygonal shape, and a slip stopper is formed on one surface, and a recess is formed on the other surface. A cam part that is fitted in a state where the washer is rotatable and is prevented from slipping out, a slip stopper is formed on the surface of the first washer that contacts the above-mentioned bolt or nut, and a downward slope in the screw tightening direction on the opposite surface. And a plurality of cam portions that engage with the cam portion of the first washer are provided in the annular direction on the bottom surface of the recess, and the inclination angle of these cam portions is the bolt or nut. The cam washer is characterized in that it is larger than the lead angle of the screw part in.