Polygonal gasket and fastening structure

Abstract

The invention provides a polygonal gasket and a fastening structure. The present invention suppresses associated rotation of a polygonal gasket by a simple structure. The polygonal washer is used by being sandwiched between a mounting surface (Sa) of a mounting object (S) and the head of a nut (2) or a bolt. The washer main body (1A) has a polygonal shape when viewed from a direction orthogonal to a surface on the nut (2) side, and a central recess (1Aa) is formed on the mounted surface (Sa) side. The outer shape of the central recess (1Aa) is formed so as to be the same as or larger than the outer shape of the nut (2) or the head of the bolt, and the central portion of the washer body (1A) has elasticity to displace toward the mounted surface (Sa) when the washer body (1A) is fastened by the nut (2) or the bolt.

Description

Technical Field

[0001] The invention relates to a polygonal gasket and a fastening structure. Background Art

[0002] Generally, bolts and nuts are used to attach an object to an object. In this case, the bolts or nuts are tightened by turning them, but regardless of the size, the lower surface of the bolts or nuts will rub against the mounting surface (supporting surface) of the object. As the bolts or nuts are tightened, the force rubbing against the mounting surface becomes stronger, so if the mounting surface is coated with paint, the paint may peel off and rub against the mounting surface under the paint.

[0003] In this case, the surface to be mounted is rough, and if it deteriorates, it becomes uneven, which reduces the commodity value of the product mounted by the bolts or nuts.

[0004] Furthermore, bolts or nuts are frequently and repeatedly loosened and tightened for maintenance, etc., and in this case, the mounting surface also becomes rough, and it is sometimes necessary to replace parts constituting the mounting surface or to beautifully repair the mounting surface.

[0005] As a solution to this problem, it is considered to avoid direct contact by clamping a flat washer (flat round washer) between the head of the bolt or nut and the mounting surface for tightening. However, in reality, when the bolt or nut is tightened, the flat washer will rotate along with the bolt or nut, and even if there is a difference in degree, the flat washer may damage the mounting surface due to the rotation.

[0006] Therefore, in order to suppress the associated rotation of the washer, the following scheme is proposed: the washer comprises a washer body and a central recess formed on the mounted surface side of the washer body, and the outer shape of the central recess (the shape of the outer peripheral edge) is the same as the outer shape of the nut or bolt head, or is larger than the outer shape of the nut or bolt head (for example, refer to patent document 1).

[0007] Patent document 1: Japanese Patent Publication No. 2021-179250 Summary of the invention Problems to be solved by the invention

[0008] However, it is required not only to improve the effect of suppressing the concomitant rotation of the gasket but also to simplify the structure.

[0009] Therefore, an object of the present invention is to provide a polygonal washer and a fastening structure capable of suppressing the associated rotation of the washer with a simple structure. Means for solving problems

[0010] The present invention is a polygonal washer, which is installed by being sandwiched between the mounted surface of the mounted object and the head of a nut or a bolt, and is characterized in that the washer body is polygonal when viewed from a direction orthogonal to the surface that becomes the head side of the nut or the bolt, a central recess is formed on the mounted surface side, the shape of the central recess is formed to be the same as or larger than the shape of the head of the nut or the bolt, and the central part of the washer body has elasticity to displace toward the mounted surface side when tightened by the nut or the bolt. Here, the central recess does not need to be formed over the entire surface, and also includes the case where a flat portion is formed on the periphery of the center hole and the outer periphery of the washer body within a range that does not impair the elasticity.

[0011] Thus, with a simple structure, when loosening or tightening a nut or a bolt, the associated rotation is eliminated, thereby preventing the mounted surface of the mounted object from being damaged due to the associated rotation.

[0012] In this case, it is preferred that the central recess is formed as a curved surface whose inner peripheral surface extends from the vicinity of the center hole of the washer body toward the outer peripheral edge, and the front end of each corner of the washer body contacts the mounted surface before being tightened by the nut or the bolt in the installed state, and when tightened, the apex of the corner sinks into the mounted surface, and the central part of the washer body is elastically deformed in a manner of displacement toward the mounted surface. Here, the curved surface shape includes a spherical surface shape, a conical surface shape, etc.

[0013] In these cases, it is preferred that an annular protrusion is formed on the head side of the nut or the bolt of the washer body, and the outer shape of the annular protrusion is the same as or smaller than the outer shape of the nut or bolt head.

[0014] Furthermore, in the mounted state, the outer peripheral edge between the corners of the washer body serves as a relief portion that forms a space between the washer body and the mounted surface before being tightened by the nut or the bolt.

[0015] Thus, the central portion of the gasket body can be elastically deformed appropriately when displaced toward the mounting surface.

[0016] Furthermore, it is preferred that a side convex portion is provided on at least one of the left and right side portions of the head portion of the nut or the bolt of the washer body, and the side surface on the center side of the side convex portion serves as a surface for restricting rotation of the nut or the bolt.

[0017] In addition, it is preferred that side protrusions are provided on the left and right sides of the head side of the nut or the bolt of the washer body, and a linear groove is formed between the side protrusions, and the width of the groove is the same as the width of the head of the nut or the bolt (the so-called two-sided width) or slightly larger than the width of the head of the nut or the bolt.

[0018] Furthermore, it is preferred that the side convex portion is formed so that the height of the upper surface gradually decreases in the counterclockwise direction.

[0019] In addition, the present invention is a fastening structure in which a polygonal washer is installed by clamping it between the installation surface of the object to be installed and the head of a nut or a bolt, and is characterized in that the polygonal washer is the polygonal washer described in any one of technical solutions 1 to 3.

[0020] The present invention has a simple structure and can eliminate associated rotation when loosening or tightening nuts or bolts, thereby preventing the mounted surface of the mounted object from being damaged due to the associated rotation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a cross-sectional view showing a fastening structure using the polygonal gasket according to the first embodiment of the present invention. Figure 2 The polygonal gasket is shown in FIG. 1 , wherein (a) is a perspective view from above, (b) is a perspective view from below, and (c) is a side view. Figure 3 A polygonal gasket according to a second embodiment of the present invention is shown. (a) is a perspective view when viewed from above, and (b) is a perspective view when viewed from below. Figure 4 (a) and (b) are perspective views showing modification examples, respectively. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

[0023] Figure 1 It is a cross-sectional view showing a fastening structure using the polygonal gasket according to the first embodiment of the present invention.

[0024] like Figure 1 As shown, the polygonal washer 1 of the present invention is used by being sandwiched between a mounting surface Sa of a mounting object S mounted on a mounting target object (not shown), for example, and a nut 2 .

[0025] The polygonal washer 1 is hexagonal when viewed from a direction perpendicular to the surface on the nut 2 side, and a central recess 1Aa is formed on the side of the washer body 1A that contacts the mounting surface Sa, and has elasticity that allows the central portion of the washer body 1A to deform in a manner close to the mounting surface Sa side by tightening the nut 2. A central hole 1a is formed in the center of the washer body 1A for the screw 4 that is screwed with the nut 2 to pass through. In addition, the polygonal washer does not need to be hexagonal when viewed from a direction perpendicular to the surface on the nut 2 side, and may be other polygonal shapes such as a triangle or a quadrilateral.

[0026] like Figure 2 As shown in (a), an annular protrusion 1B protruding from the washer body 1A toward the nut 2 is integrally formed on the side of the polygonal washer 1 that contacts the nut 2. The inner peripheral wall surface of the annular protrusion 1B is continuous with the inner peripheral wall surface of the center hole 1a. When the nut 2 used for fastening has a hexagonal cross-section, the outer shape of the annular protrusion 1B is an outer shape of the same size as the interval L (width across the two surfaces) between the two parallel surfaces. In addition, the minimum diameter required for the annular protrusion 1B is the same size as the interval L between the two parallel surfaces of the nut 2.

[0027] like Figure 2 As shown in (a) and (b) of FIG. 1 , the central recess 1Aa is formed into a curved surface in which the inner peripheral surface of the recess extends from the peripheral edge of the center hole 1a of the polygonal washer 1 toward the outer peripheral edge 1Ac over the entire surface. The outer peripheral edge 1Ac forms a relief portion between the corners 1Ab of the washer body 1A to form a space between the washer body 1A and the mounting surface Sa. That is, when the washer body 1A is in the installed state and before being tightened by the nut 2, the front ends of the corners 1Ab of the washer body 1A are in contact with the mounting surface Sa, but the outer peripheral edge 1Ac between the corners 1Ab is separated from the mounting surface Sa. Moreover, when tightening, the center part of the washer body 1A is pressed down in a manner close to the mounting surface Sa side, thereby the apex of the corner 1Ab sinks into the mounting surface, and the center part of the washer body 1A is elastically deformed as a whole in a manner close to the mounting surface Sa side, and the elastic deformation is not hindered by the presence of the relief portion.

[0028] The outer shape of the central recess 1Aa (the shape of the outer peripheral edge) is formed to be the same as or larger than the outer shape of the nut 2 (or the head of the bolt). Such a central recess 1Aa is provided because if the surface where the polygonal washer 1 contacts the mounting surface Sa of the mounted object S is made concave near the central portion, direct contact between the central portion of the polygonal washer 1 and the mounting surface Sa of the mounted object S can be avoided.

[0029] like Figure 1As shown in FIG. 1 , when tightening with the nut 2, the lower surface of the nut 2 (the surface on the side of the object S to be mounted) contacts only the upper surface of the annular convex portion 1B of the polygonal washer 1. Only the vertices (front ends) of the six corners 1Ab of the lower surface of the polygonal washer 1 contact the mounted surface Sa. That is, the spider (polygonal washer) is in a state of standing on the ground (mounted surface).

[0030] When the nut 2 is tightened relative to the screw 4 through the polygonal washer 1, the lower surface of the nut 2 is tightened while rubbing (sliding) on ​​the upper surface of the polygonal washer 1 (the upper surface of the annular protrusion 1B), but the polygonal washer 1 does not rotate with the nut 2 at all and remains stationary relative to the mounting surface Sa of the mounted object S. By tightening, the vertices of the six corners 1Ab of the polygonal washer sink into the mounting surface Sa, the associated rotation effect of the polygonal washer 1 is improved, and the central part of the washer body 1A is elastically deformed in a manner of displacement toward the mounting surface Sa. Therefore, the polygonal washer 1 can have a diameter equal to that of the nut support surface (or an outer shape that is the same as the shape of the nut).

[0031] The polygonal washer 1 remains stationary with respect to the mounting surface Sa, and therefore, as a result, the polygonal washer 1 hardly damages the mounting surface Sa.

[0032] In this way, the polygonal washer 1 does not rotate with the nut 2, that is, the nut 2 slides on the upper surface of the polygonal washer 1 (the upper surface of the annular protrusion 1B), and the lower surface of the polygonal washer 1 does not slide at all relative to the mounted surface Sa based on the following reasons. As described in Japanese Patent Publication No. 2021-179250, the friction force between the nut and the polygonal washer and the friction force between the polygonal washer and the mounted surface have nothing to do with the size of the area of ​​their contact parts, but are only related to the pressing force generated by the nut 2, and are the same. In addition, the nut 2 contacted by the polygonal washer 1 is iron, and the mounted object S is also iron, which is the same material. Therefore, it can be considered that even if there is a slight difference in the friction coefficients μ1 and μ2, μ1 and μ2 are almost equal. Therefore, the final friction force is equal.

[0033] On the other hand, when the nut 2 is tightened (the same is true when it is loosened), whether the polygonal washer 1 generates "joint rotation" depends on the difference in magnitude between the force (torque = rotational force T1) to rotate the polygonal washer 2 and the rotational resistance (torque = rotational resistance T2) that acts so that the polygonal washer 1 does not rotate relative to the mounted surface Sa. Therefore, by providing the central recess 1Aa, the rotational resistance T2 that acts so that the polygonal washer 1 does not rotate relative to the mounted surface Sa is larger than the force T1 that rotates the polygonal washer 1 by the friction force between the nut 2 and the polygonal washer 1. That is, by providing the central recess 1Aa, the length R2 (radius) from the rotation center to the contact portion between the polygonal washer and the mounted surface is greater than the length R1 from the rotation center to the contact portion between the nut 2 and the polygonal washer 1. Even if the friction force is the same, the rotational resistance T2 of the polygonal washer 1 is greater than the force T1 of the nut 2 to rotate the polygonal washer 1. As a result, the polygonal washer 1 does not rotate, but only the nut 2 rotates.

[0034] As described above, the embodiments of the present invention have been described with reference to the drawings, but various additions and changes can be made without departing from the gist of the present invention.

[0035] (i) In the above embodiment, the present invention is applied to a polygonal washer provided between a nut and a mounting surface of a mounting object. However, the present invention is not limited thereto and can also be similarly applied to a polygonal washer provided between a bolt head and a mounting object. (ii) If Figure 3 As shown in (a) and (b), two shoulder portions 11a (side convex portions) may be provided on the side opposite to the side in contact with the mounting surface Sa provided with the central recess, so as to form a polygonal washer 11 having a linear groove 11b (linear groove portion) of a certain width in the diameter direction. The linear groove 11b has a width that is the same as or slightly larger than the interval L between two parallel planes of the head of the hexagonal bolt, and is a size for the head of the hexagonal bolt (or nut) used for tightening to be embedded. Here, the shoulder portion 11a (side convex portion) does not need to be provided on the left or right side of the polygonal washer, and may be provided on only one of the left or right side. In addition, it does not need to be provided on the corner, and may be provided on the flat surface. (iii) If Figure 3 As shown in (a) and (b), when the shoulder portion 11a (side convex portion) is provided, as shown in Figure 4 (a), (b) ( Figure 4 (a) is the two shoulder parts, Figure 4As shown in (b) of the figure, the upper surfaces of the shoulder portions 11Aa, 11Aa, 11Ba of the polygonal washers 11A and 11B are preferably in the shape of an inclined surface whose height gradually decreases in the counterclockwise direction (i.e., around the counterclockwise direction). This is because, at the beginning of tightening the nut, even if a part of the head of the bolt rests on the shoulder portions 11Aa, 11Aa, 11Ba (side convex portions), if it is slightly turned to one side of the tightening nut, the head automatically rotates and slides along the inclined surface together with the bolt that cannot be seen from the side of the tightening nut, and can be smoothly embedded in the normal position. In addition, the side surface on the center side of the shoulder portion does not need to be a plane, as long as it is a surface that limits the rotation of the nut or bolt. In this case, an inclined surface whose height decreases in the counterclockwise direction can also be formed on the shoulder portion. Description of reference numerals:

[0036] 1, 11, 11A, 11B: polygonal washers; 1A: washer body; 1Aa: central recess; 1Ab: corner; 1Ac: outer peripheral edge; 1B: annular protrusion; 2: nut; 4: screw; 11: polygonal washers; 11a: shoulder; S: mounted object; Sa: mounted surface.

Claims

1. A polygonal washer, which is installed by being sandwiched between the mounting surface of the object to be mounted and the head of a nut or bolt, characterized in that: The washer body is polygonal when viewed from a direction perpendicular to a surface that becomes a head side of the nut or the bolt, and has a central recessed portion formed on the mounting surface side. The central recessed portion is formed to have an outer shape that is the same as or larger than an outer shape of a head of the nut or the bolt. When the washer body is fastened by the nut or the bolt, the central portion of the washer body has elasticity to be displaced toward the mounting surface.

2. The polygonal gasket according to claim 1, wherein: The central recess is formed into a curved surface whose inner peripheral surface extends from the vicinity of the center hole of the gasket body toward the outer peripheral edge. When the washer body is in the installed state, before being tightened by the nut or the bolt, the front ends of the corners of the washer body are in contact with the installed surface. During tightening, the apexes of the corners sink into the installed surface, and the central part of the washer body is elastically deformed in a manner displaced toward the installed surface.

3. The polygonal gasket according to claim 2, wherein: In the mounted state, the outer peripheral edge between the corners of the washer body serves as a relief portion that forms a space between the washer body and the mounted surface before being tightened by the nut or the bolt.

4. The polygonal gasket according to claim 1, wherein: An annular convex portion is formed on the head side of the nut or the bolt of the washer body. The outer shape of the annular protrusion is the same as or smaller than the outer shape of the head of the nut or the bolt.

5. The polygonal gasket according to claim 1, wherein: A side convex portion is provided on at least one of the left and right side portions of the washer body on the head side of the nut or the bolt. The side surface on the center side of the side projection serves as a surface for restricting the rotation of the nut or the bolt.

6. The polygonal gasket according to claim 1, wherein: On the head side of the nut or the bolt of the washer body, side convex parts are provided on the left and right sides. A linear groove is formed between the side convex portions. The width of the groove portion is the same as or slightly larger than the width of the head of the nut or the bolt.

7. The polygonal gasket according to claim 5 or 6, wherein: The side convex portion is formed such that the height of the upper surface gradually decreases in the counterclockwise direction.

8. A fastening structure, wherein a polygonal washer is installed by clamping it between the mounting surface of the object to be mounted and the head of a nut or bolt, characterized in that: The polygonal gasket is the polygonal gasket according to any one of claims 1 to 3.

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