JP2541283Y2 - Bolts with built-in washers for stabilizing the axial force - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a bolt with a washer built-in for stabilizing the tightening axial force,
In particular, the present invention relates to a washer-incorporated bolt that can improve axial force management when bolting.

2. Description of the Related Art Generally, a fastening operation using a bolt and a washer is often employed in order to fix a member to be mounted, which is a component, to a mounting member such as a main body of a mechanical device. Conventional examples of bolts and washers used for fastening such components are shown in FIGS. 5 to 7. FIG. In these figures, reference numeral 1 denotes a bolt for fixing a component, and the bolt 1 has a head 2 to which a rotating action such as a spanner is applied;
It comprises a component contact portion 3 provided below the head 2 and having a seating surface on the back surface, and a leg portion 5 provided with a screw portion 4 at a lower end portion. A washer 6 is attached to the leg 5 of the bolt 1 to improve the tightening efficiency of the bolt 1. A flat spring washer is used for the washer 6, for example, the outer diameter is 21 mm (mm), and the diameter of the bolt insertion hole 8 is
When the thickness is 10.1 mm and the plate thickness is 2.2 mm, a dimensional difference of 0.55 mm (this is referred to as a depth) between the inner peripheral edge of the bolt insertion hole 8 and the outer edge of the washer 6 is formed by press forming or the like. Is molded. When such a washer 6 is mounted on the bolt 1 to mount a component, the washer 6
The protruding outer peripheral edge 6a contacts the component, while the protruding inner peripheral edge 6b contacts the seat surface of the component contact surface 3 of the bolt 1. When the bolt 1 is rotationally tightened in this state, a rotation preventing action acts on the washer 6 due to a difference in moment, and the bolt 1 is tightened with a constant torque while gradually deforming the washer 6 into a flat shape.

However, in such a conventional flat spring washer-incorporated bolt, the contact between the seat of the bolt 1 and the washer 6 is unstable, so that when the bolt 1 is screwed in, the rotational torque of the bolt 1 is increased. The value of the bolt axial force with respect to is not uniquely (or substantially constant), and as shown in FIG. 7, a considerable amount of the bolt axial force is increased until the rotation torque of the bolt 1 reaches the contact torque of the flat spring washer. There is variation (indicated by V1 in FIG. 7). Therefore, even when it is desired to tighten the components with a certain axial force when mounting the components, it is not clear how much the rotating torque should be,
There was a problem that the axial force could not be stably realized.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a washer-integrated bolt capable of obtaining a stable axial force in a bolt tightening operation.

Means for Solving the Problems In order to achieve the above object, the present invention provides a washer used for a washer-incorporated bolt, on a surface in contact with the bolt head, at a predetermined radial position from the center of the washer, in a circumferential direction. The gist is that an extending groove or bead is formed.

Action When a bolt is inserted through a washer and a part is tightened, the seat surface of the bolt comes into contact with the inner peripheral edge of the washer as the bolt is tightened, and this washer is pinched between the bolt head and the part. wear. Since grooves and beads are provided on the bolt contact surface of the washer, the shape of the washer changes as the bolt is tightened, and as the plate becomes flat, the contact surface between the bolt and the washer is limited. It becomes. Furthermore, there is an effect of an oil pool. Accordingly, when the bolt is tightened, the variation between the rotational torque applied to the bolt and the axial force of the bolt is reduced, and the management of the axial force of the bolt is facilitated.

Embodiment FIGS. 1 to 3 show a first embodiment of a washer-incorporated bolt according to the present invention.

Since the washer-incorporated bolt according to this embodiment has substantially the same structure as the bolt 1 described above as the conventional example, the same reference numeral is given to the conventional bolt 1 and the same component is given to the same component as the conventional bolt. The detailed description is omitted.
1 and 2, reference numeral 11 denotes a washer.
The washer 11 has a bolt insertion hole 12 and has the same structure as the conventional washer 6 in outer diameter and depth. However, unlike the past, the upper surface of the washer 11
A groove 13 extending in the circumferential direction is formed on the surface in contact with the bolt head 2. One or a plurality of the grooves 13 are provided at predetermined positions in the radial direction from the center of the washer. And the groove 13 is a washer
Even if there is some variation in the depth between the bolts 11, the bolts 1 are arranged within the range of the washer surface that abuts on the seating surface of the bolt head 2 as the bolt 1 is tightened.

The operation of the washer-integrated bolt having such a configuration will be described below.

When fastening the mounted member to the mounting member by the bolt 1 and the washer 11 according to this embodiment, when the bolt 1 is tightened, the outer peripheral edge 11a of the washer 11 comes into contact with the contact surface of the mounted member. Under the state, the torque is applied to the bolt 1 from when the seating surface 3 of the bolt 1 comes into contact with the protruding inner peripheral edge 11 b of the washer 11. As shown in FIG. 3, the torque gradually increases from 0 as the bolt 1 is rotated, and the axial force of the bolt 1 also increases. The state of increasing force changes. This change in the increase in the bolt axial force with respect to the rotation torque of the bolt is called the adhesion torque and is indicated by ST in FIG. This contact torque corresponds to the stage in which the washer 11 formed in a further shape is crushed by the screwing of the bolt 1, and the portion further than the contact torque ST does not involve further deformation of the washer 11. This represents a state where the axial force is increased only by screwing the bolt 1.

In this embodiment, a groove 13 extending in the circumferential direction is formed at a predetermined position in the radial direction from the center of the washer on a surface 11a of the washer 11 which is in contact with the head 2 of the bolt. , Bolt 1 and washer
The contact surface of the bolt 11 is limited, and the variation V2 of the axial force with respect to the rotation torque of the bolt 1 is reduced.

 FIG. 4 is a view showing a second embodiment of the present invention.

In this embodiment, a bead 15 extending in the circumferential direction is formed on the upper surface 14a of the washer 14, unlike the groove 13. The operation at the time of bolt tightening is the same as that of the first embodiment. That is, by providing this bead, the contact surface between the bolt 1 and the washer 14 is limited as the bolt 1 is screwed in, and the variation in the axial force with respect to the rotational torque of the bolt 1 is reduced.

Effect of the Invention As described above, according to the present invention, a groove or a bead is provided on the bolt contact surface of the washer in the washer built-in bolt, so that the contact surface between the bolt and the washer is limited according to the screwing of the bolt, Thus, it is possible to minimize the variation in the axial force with respect to the rotational torque, and to easily control the axial force of the bolt when fastening the mounted component to the mounting component.

[Brief description of the drawings]

1 is a perspective view of a washer used in a first embodiment of a washer-integrated bolt according to the present invention, FIG. 2 is a cross-sectional view of the washer, and FIG. FIG. 4 is a sectional view of a washer used in the second embodiment of the washer-integrated bolt of the present invention, FIG. 5 is a front view showing the washer-incorporated bolt to which the present invention is applied, FIG. 6 is a cross-sectional view showing a conventional example of a washer incorporated in the bolt, and FIG. 7 is a view showing a relationship between torque and axial force when the bolt is screwed in the conventional example. 1 ... bolt, 2 ... head, 4 ... shaft, 11, 14 ... washer, 11a ... top surface, 13 ... groove, 15 ... bead

Claims (2)

(57) [Scope of request for utility model registration] 1. A bolt in which a bolt-shaped washer is incorporated in a bolt leg portion, and a member to be mounted is fastened to a mounting member with the intervention of the washer. A groove extending in a circumferential direction is formed at a predetermined position within a range where the bolt hits a bearing surface of the bolt head as the bolt is tightened radially outward from the center of the washer. Bolt with washer for stabilizing axial force. 2. The bolt according to claim 1, wherein a bead extending in the circumferential direction is formed in a convex shape instead of the groove.