Anti-loosening washer

Abstract

This invention provides a locking washer that is installed between a hexagonal nut, which is screwed onto a bolt to fasten an object, and the object to be fastened, preventing the hexagonal nut from loosening after fastening without damaging the threaded portion of the bolt. [Solution] The anti-loosening washer has multiple tongue-shaped pieces and slits alternately formed in the circumferential direction on the inner circumference of the flange of an annular or polygonal hole annular shape, and female threads are formed at the tips of the tongue-shaped pieces so that the female threads are tightly fitted onto the bolt when fastened, and it is integrated with the hexagonal nut by an integration means to prevent the hexagonal nut from loosening.

Description

Detailed Description of the Invention

Technical Field

[0001] The present invention relates to a locking washer installed between a hexagonal nut that is screwed onto a bolt penetrating a fastened object to fasten the fastened object and the fastened object to prevent loosening of the hexagonal nut.

Background Art

[0002] Preventing loosening of nuts and bolts for fastening fastened objects with a locking washer has already been conventionally practiced.

[0003] As a first example of this type of locking washer, there is a description in "Patent Document 1". This locking washer has gear-shaped irregularities on the outer or inner circumference of an annular plate. The axial cross-section of the irregularity portion is semi-circular, and an example is shown in which loosening of the bolt is prevented by the first-stage and second-stage repulsive forces when the locking washer is compressed.

[0004] As a second example, there is a description in "Patent Document 2". By biting the claws formed in the inner diameter portion of an annular washer (locking washer) into the thread portion of the bolt during fastening, the claws are fixed to the bolt, and at the same time, a cotter as an integration means for the outer peripheral portion is bent along the side surface of the nut to integrate the nut and the washer to prevent loosening of the nut. An example is shown.

[0005] As a third example, there is a description in "Patent Document 3". An inner ring (locking washer) is engaged with a recess formed on the nut seating surface. By cutting the thread portion of the bolt with a longitudinal blade formed in the inner diameter portion during fastening, the longitudinal blade is fixed to the bolt, and at the same time, the radial expansion of the inner ring is restricted by the recess on the nut seating surface to integrate the inner ring, the nut, and the bolt to prevent loosening of the nut. An example is shown.

[0006] As a fourth example, there is a description in "Patent Document 4". An example is shown in which the male thread portion is pressed by the tip portion of a leaf spring of a locking washer to prevent loosening of an integral hexagonal nut that is fitted with the locking washer. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Publication No. 48-085070 [Patent Document 2] Publication No. 53-140855 [Patent Document 3] Japanese Patent Application Publication No. 53-014263 [Patent Document 4] Japanese Patent Publication No. 2022-075946 [Overview of the project] [Problems that the invention aims to solve]

[0008] In the example in "Patent Document 1," the loosening of the bolt is prevented by the first and second repulsive forces when the anti-loosening washer is compressed. However, the anti-loosening effect in this case is the same as that of a standard spring washer, and there was a problem in that it could not provide a sufficient anti-loosening effect.

[0009] In the example described in "Patent Document 2," there was a problem in that the claws of the anti-loosening washer damaged the threaded portion of the bolt.

[0010] In the example described in "Patent Document 3," there were problems such as the vertical blades of the inner ring (anti-loosening washer) damaging the threaded portion of the bolt, and the need for a special nut instead of a standard one.

[0011] In the example of "Patent Document 4," as shown in Figure 3(b), if the tip portion 1e of the leaf spring 1b is a surface perpendicular to the plane of the leaf spring 1b, only the apex of the threads of the male screw 3 will be pressed, resulting in the problems of damage to the thread apex and insufficient fixing force between the locking washer 1 and the male screw 3. Furthermore, as shown in Figure 5(a), when the tip portion 1e of the leaf spring 1b is shaped like a wedge 1f, as the hexagonal nut 2, which is fitted into the locking washer 1 and screwed onto the male thread 3, is rotated in the tightening direction, the tip portion 1e that is in contact with the surface of the object to be fastened 4 moves in the direction of the male thread 3. When the wedge-shaped tip portion 1e engages with the male thread 3, the hexagonal nut 2 and the locking washer 1, which are fitted together as one unit, can no longer rotate. Consequently, there was a problem in that the leaf spring 1b could not be tightly attached to the object to be fastened 4 with the hexagonal nut 2, as shown in Figure 5(b). Furthermore, in Figure 5(a), if the tip portion 1e of the leaf spring 1b were to be female-threaded, as the hexagonal nut 2, which is fitted into the locking washer 1 and screwed onto the male thread 3, is rotated in the tightening direction, the tip portion 1e that is in contact with the surface of the object to be fastened 4 will move in the direction of the male thread 3. Once the female thread is screwed onto the male thread 3, the hexagonal nut 2 and the locking washer 1, which are fitted together as one unit, will no longer be able to rotate. Consequently, a problem arises in that the leaf spring 1b cannot be tightly fitted to the object to be fastened 4 with the hexagonal nut 2, as shown in Figure 5(b).

[0012] This invention has been made in view of the above-mentioned problems with anti-loosening washers, and aims to provide an anti-loosening washer that can be used with a standard hexagonal nut for fastening, prevents the hexagonal nut from loosening after fastening without damaging the threaded portion of the bolt. [Means for solving the problem]

[0013] The first anti-loosening washer of the present invention, which solves the above problems, has a flange made of an elastic material with an annular or polygonal hole annular shape, on which a plurality of inverted pyramidal tongue-shaped pieces and a plurality of slits are alternately formed in the circumferential direction on the inner circumference, and is installed between a hexagonal nut that fastens a fastened object by screwing it onto a bolt that passes through the fastened object and the fastened object, and when fastened the tip of the tongue-shaped piece is fixed to the bolt and the flange and the hexagonal nut are integrated to prevent the hexagonal nut from loosening, wherein a female thread that is screwed onto the bolt is formed at the tip of the tongue-shaped piece, and the tongue-shaped piece and the slit are formed so that when fastened the female thread is reduced by a required amount from its initial state, and the female thread is fixed to the bolt when fastened.

[0014] The second anti-loosening washer of the present invention is the first anti-loosening washer of the present invention described above, wherein a plurality of elastic latches protruding axially upward are formed on the flange portion, and during fastening, the latches elastically deform to allow rotation of the hexagonal nut in the tightening direction, and at the time of fastening, at least one of the latches protruding outside the range of the seating surface of the hexagonal nut abuts against the side surface of the hexagonal nut to prevent rotation of the hexagonal nut in the loosening direction, thereby integrating the flange portion and the hexagonal nut. [Effects of the Invention]

[0015] The anti-loosening washer of the present invention can be installed between a hexagonal nut, which is screwed onto a bolt to fasten an object, and the object to be fastened, thereby preventing the hexagonal nut from loosening after fastening without damaging the threaded portion of the bolt. Furthermore, instead of special hexagonal nuts, standard hexagonal nuts can be used to fasten the objects to be fastened. [Brief explanation of the drawing]

[0016] [Figure 1] This is a longitudinal cross-sectional view of a locking washer according to the first embodiment of the present invention. [Figure 2] Similarly, this is a view from arrow A in Figure 1. [Figure 3]Similarly, it is a longitudinal sectional view showing the deformed state of the anti-loosening washer during compression. [Figure 4] Similarly, it is a longitudinal sectional view showing the deformed state of the anti-loosening washer during compression. [Figure 5] Similarly, it is a longitudinal sectional view showing the state where the anti-loosening washer is installed in the fastening part. [Figure 6] Similarly, it is a longitudinal sectional view showing the state where the anti-loosening washer abuts against the fastened object. [Figure 7] Similarly, it is a longitudinal sectional view showing the state where the fastened object is fastened with a hexagonal nut. [Figure 8] Similarly, it is a side view showing the state where the flange portion of the anti-loosening washer is bent. [Figure 9] Similarly, it is a view taken along the arrow B in FIG. 8. [Figure 10] It is a plan view of the anti-loosening washer according to the second embodiment of the present invention. [Figure 11] Similarly, it is a sectional view taken along the arrow C-C in FIG. 10. [Figure 12] Similarly, it is a longitudinal sectional view showing the state where the anti-loosening washer is installed in the fastening part. [Figure 13] Similarly, it is a longitudinal sectional view showing the state where the fastened object is fastened with a hexagonal nut. [Figure 14] Similarly, it is a view taken along the arrow D in FIG. 13.

Embodiments for Carrying out the Invention

[0017] Hereinafter, embodiments of the anti-loosening washer according to the present invention will be described with reference to the accompanying drawings.

[0018] FIGS. 1 to 9 show the first embodiment of the present invention. As shown in FIGS. 1, 2, 5, and 9, the anti-loosening washer 1 made of an elastic body has a plurality of reverse conical surface-shaped (reverse circular conical surface-shaped or reverse pyramidal surface-shaped) tongue-shaped pieces 1n and a plurality of slits 1c formed alternately in the circumferential direction on the inner peripheral portion of a horizontal flange 1g having an annular shape or a polygonal hole annular shape. The tongue-shaped flap 1n has a base that forms the inclined surface 1i of an inverted thruster, and a tip that is horizontal and forms an annular jaw 1e. A female thread 1a is formed at the tip of the tongue-shaped piece 1n for screwing onto the bolt 5, and a slit 1c is formed radially from the female thread 1a to the slit end 1d. The boundary between the jaw 1e and the slope 1i is the jaw boundary 1f, and the boundary between the slope 1i and the brim 1g is the brim boundary 1k. The outer circumference of flange 1g is circular with an outer diameter of 1h, which is larger than the diagonal width 4d of hexagonal nut 4.

[0019] Using Figure 3, we will explain the deformation state when a locking washer 1, where the slit end 1d and the flange boundary 1k are in the same position, is sandwiched between two flat plates (not shown) and compressed in the axial direction. When the anti-loosening washer 1 is compressed, the inclined surface 1i deforms horizontally as a cantilever beam with the flange boundary 1k as the fixed end, and finally, the tongue-shaped piece 1n (jaw 1e and inclined surface 1i) and the flange 1g deform into a single plane. The horizontal distance from the flange boundary 1k to the female thread 1a changes from Y before deformation (initial state) to X after deformation. If X1 is the slope distance from the flange boundary 1k to the jaw boundary 1f, and X2 is the horizontal distance from the jaw boundary 1f to the female thread 1a, then X is the sum of X2 and the horizontally expanded X1. The difference between X and Y is the amount Z of reduction in the internal thread 1a when the anti-loosening washer 1 is compressed into a single plane from its initial state.

[0020] Using Figure 4, we will explain the deformation state of a locking washer 1 when it is compressed axially while sandwiched between two flat plates (not shown), where the slit end 1d is radially inward from the flange boundary 1k and the shape of the inclined surface 1i is an inverted cone. When the anti-loosening washer 1 is compressed, initially, a portion of the slope 1i from the circle of diameter F to the jaw boundary 1f deforms horizontally, acting as a cantilever beam with the circle of diameter F passing through the slit end 1d as the fixed end. The portion of the slope 1i that has been deformed horizontally becomes one plane with the jaw 1e. The horizontal distance from the circle of diameter F to the female thread 1a changes from U before deformation (initial state) to T after deformation. If the slope distance from the circle of diameter F to the jaw boundary 1f is T1, and the horizontal distance from the jaw boundary 1f to the female thread 1a is T2, then T is the sum of T2 and the horizontally expanded T1. The difference between T and U is the temporary reduction amount V of the female thread 1a. Next, the disc spring structure, which has a circle with diameter F passing through the slit end 1d as its inner diameter and a flange boundary 1k as its outer diameter, deforms into a flattened shape, and finally, the locking washer 1 deforms into a single plane. As the inner diameter of the disc spring expands when it deforms into a flattened shape, if the amount of expansion of the radius of the circle with diameter F (corresponding to the inner diameter of the disc spring) is W, then the amount of expansion of the female thread 1a at the tip of the tongue-shaped piece 1n, which is integrated with the circle with diameter F, is also W. The difference between the provisional reduction amount V and the expansion amount W is the actual reduction amount S of the female thread 1a when the locking washer 1 is compressed into a single plane from its initial state. Furthermore, according to publicly available documents from Tokai Spring Industry Co., Ltd. (Spring Technology and Calculation Information: Disc Springs, Calculation Formulas, Guides and Clearances), disc springs "increase in inner diameter and decrease in outer diameter as they are compressed."

[0021] As described above, the amount of reduction in the internal thread 1a when the anti-loosening washer 1 is compressed and deformed in a single plane varies depending on the state of the slope 1i and the slit 1c (slit end 1d). This anti-loosening washer 1 is designed to have a tongue-shaped piece 1n and a slit 1c formed so that the female thread 1a is reduced by a required amount from its initial state when fastened (when in a flat state), thereby securing the female thread 1a to the bolt 5 (see Figure 7) in an appropriate tight fit state when fastened.

[0022] Using Figure 5, we will explain the state in which the anti-loosening washer 1 is installed on the fastening part. A locking washer 1 is installed between the hexagonal nut 4, which is screwed onto a bolt 5 that passes through the fastened objects 6 and 7, and the fastened object 6. The locking washer 1 has its female thread 1a screwed onto the bolt 5 with the lower surface of its jaw 1e facing the fastened object 6. The locking washer 1 and hexagonal nut 4, which are screwed onto the bolt 5 respectively, can rotate independently or simultaneously.

[0023] Using Figure 6, we will explain the state in which the lower surface of the jaw 1e of the locking washer 1 is in contact with the object to be fastened 6. The locking washer 1, with its jaw 1e in contact with the 6 surfaces of the fastened object, cannot rotate any further in the tightening direction. However, the hexagonal nut 4 can rotate in the tightening direction as its seating surface slides on the flange 1g surface, thereby compressing the locking washer 1.

[0024] Using Figure 7, we will explain the state in which the objects to be fastened 6 and 7 are fastened together with the hexagonal nut 4. As mentioned above, the anti-loosening washer 1 is designed so that when fastened (in a flat state), the internal thread 1a portion shrinks by the required amount compared to its initial state, allowing the internal thread 1a portion to be properly secured to the bolt 5 in an appropriate tight fit during fastening. When the anti-loosening washer 1 is secured to the bolt 5, its outer diameter 1h expands in accordance with the amount of tight fit due to the reduction in the internal thread 1a. Therefore, the tolerance between the internal thread 1a of the anti-loosening washer 1 and the bolt 6 becomes large. Since the lower surface of the horizontal jaw 1e is in contact with the object to be fastened 6 from the start to the completion of fastening, the horizontal orientation of the female thread 1a at the tip of the jaw 1e does not change. Therefore, no bending stress is generated in the threads of the bolt 5, and since the female thread 1a is fixed to the bolt 5 with its entire thread surface, the female thread 1a does not damage the threads of the bolt 5.

[0025] Using Figures 8 and 9, we will explain the state in which the outer edge of flange 1g is bent during fastening, integrating flange 1g with the hexagonal nut 4. As mentioned above, the flange 1g is circular with an outer diameter of 1h, which is larger than the diagonal width 4d of the hexagonal nut 4. During fastening, the outer edge of the flange 1g is bent along the side surface 4a of the hexagonal nut 4 to form a bend 1m as an integrating means, thereby integrating the flange 1g (anti-loosening washer 1) and the hexagonal nut 4. The locking washer 1, fixed to the bolt 5, prevents the integrated hexagonal nut 4 from loosening. Since the outer shape of the flange 1g is a circle larger than the diagonal width 4d, regardless of the relative positional relationship between the locking washer 1 and the hexagonal nut 4 in the circumferential direction during fastening, the bend 1m will be a symmetrical mountain shape along the entire width of the side length 4b of the hexagonal nut 4. Therefore, depending on the surrounding conditions, the side 4a that facilitates the bending work can be selected.

[0026] Figures 10 to 14 show a second embodiment of the present invention. As shown in Figures 10 and 11, the elastic anti-loosening washer 2 has multiple notches 2q formed on the outer circumference of the flange 2g, which has an outer diameter 2h larger than the diagonal width 4d of the hexagonal nut 4. The radially outer portions of the notches 2q are bent diagonally along the bending line 2r to form multiple elastic latches 2p that protrude in an inclined shape axially upward, forming an integrated means. When the seating surface of the hexagonal nut 4, which rotates in the tightening direction during fastening, comes into contact with the latch 2p, the inclined latch 2p elastically deforms to allow the hexagonal nut 4 to rotate in the tightening direction. Regardless of the relative positional relationship between the locking washer 2 and the hexagonal nut 4 in the circumferential direction during fastening, the side surface 2s of at least one latch 2p, which protrudes in an inclined shape in its initial state outside the seating surface of the hexagonal nut 4, is configured to contact the side surface 4a of the hexagonal nut 4 in order to prevent rotation of the hexagonal nut 4 in the loosening direction. The anti-loosening washer 2 has the same structure as the anti-loosening washer 1 described above, except for the latch 2p portion. Note that this diagram corresponds to a right-hand threaded hexagonal nut 4; for a left-hand threaded hexagonal nut 4, the diagram will be symmetrical to this one.

[0027] Using Figure 12, we will explain the state in which the anti-loosening washer 2 is installed on the fastening part. With the lower surface of the jaw 2e in contact with the object to be fastened 6, a locking washer 2 that screws onto the bolt 5 is installed in the fastening portion between the hexagonal nut 4 and the object to be fastened 6. The lock washer 2, which is screwed onto the bolt 5 and whose lower jaw 2e is in contact with the fastened object 6, cannot rotate any further in the tightening direction. In this state, as the hexagonal nut 4 is rotated in the tightening direction, the hexagonal nut 4 compresses the lock washer 2 while elastically deforming the slanted latch 2p that is in contact with the seating surface into a planar shape.

[0028] The state in which the objects to be fastened 6 and 7 are fastened together with a hexagonal nut 4 will be explained using Figures 13 and 14. The hexagonal nut 4 presses the locking washer 2 onto the fastened object 6 in a flat plane, and secures the female thread 2a to the bolt 5 in a tight fit. Outside the seating area of ​​the hexagonal nut 4, the side surface 2s of at least one latch 2p, which is initially projecting in a slanted shape, abuts against the side surface 4a to prevent rotation of the hexagonal nut 4 in the loosening direction, thereby integrating the flange 2g (loosening prevention washer 2) and the hexagonal nut 4. The locking washer 2, which is fixed to the bolt 5, is integrated with the hexagonal nut 4, preventing the hexagonal nut 4 from loosening.

[0029] According to the first and second embodiments, there is no need to press the anti-loosening washer 1 or 2 from the outer diameter side by separate means or to restrain the outer diameter portion. By compressing the anti-loosening washer 1 or 2 axially with a standard hexagonal nut 4, the anti-loosening washer 1 or 2 can be fixed to the bolt 5 without damaging the bolt 5. With the anti-loosening washer 2, simply fastening it with the hexagonal nut 4 prevents the hexagonal nut 4 from rotating in the loosening direction by the latch 2p, thereby preventing the hexagonal nut 4 from loosening.

[0030] Suitable materials include elastically deformable steel and spring materials, while materials that undergo plastic deformation are unsuitable. The appropriate thickness varies depending on the size of the hexagonal nut 4 at the application site. If it is too thin, the fastening force will be weak, and if it is too thick, the tightening force of the hexagonal nut 4 will be excessive. Examples include thicknesses of 0.2 mm to 5 mm. By increasing the frictional force of the female threads 1a and 2a, the fixing force can be increased, thereby enhancing the anti-loosening effect.

[0031] Although embodiments of the present invention have been described above, the embodiments described above do not limit the invention as defined in the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention. [Explanation of symbols]

[0032] 1. Anti-loosening washer 1a Female thread 1c slit 1d slit end 1e Ago 1f jaw boundary 1g Tsuba 1h outer diameter 1i Slope 1k flange boundary 1m bend 1n tongue 2. Anti-loosening washer 2a Female thread 2e jaw 2g Tsuba 2h outer diameter 2p latch 2q Notch 2r folding line 2s side 4 Hex nuts 4a side 4b Side length 4c Width across flats 4d diagonal width 5 volts 6 Object to be fastened 7 Object to be fastened

Claims

1. A locking washer is provided in which a plurality of inverted pyramidal tongue-shaped pieces and a plurality of slits are alternately formed in the circumferential direction on the inner circumference of an annular or polygonal hole annular flange made of an elastic material, and is installed between a hexagonal nut that is screwed onto a bolt passing through the object to be fastened and the object to be fastened, and when fastened the tip of the tongue-shaped pieces is fixed to the bolt and the flange and the hexagonal nut are integrated to prevent the hexagonal nut from loosening, A locking washer having a female thread formed at the tip of the tongue-shaped piece that screws onto the bolt, and the tongue-shaped piece and the slit are formed so that the female thread shrinks by a required amount from its initial state when fastened, thereby fixing the female thread to the bolt when fastened.

2. In the anti-loosening washer according to claim 1, A locking washer having multiple elastic latches projecting upward in the axial direction onto the flange portion, wherein during fastening, the latches elastically deform to allow rotation of the hexagonal nut in the tightening direction, and at the time of fastening, at least one of the latches projecting outside the range of the seating surface of the hexagonal nut abuts against the side surface of the hexagonal nut to prevent rotation of the hexagonal nut in the loosening direction, thereby integrating the flange portion and the hexagonal nut.

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