JPH04119211A - Disk-shaped spring seat - Google Patents

Abstract

PURPOSE:To prevent a disk screw or a member to be fastened from being damaged to maintain the initial spring force for a long period by forming to protrude an inwardly swelling part on the intermediate inner circumferential face of inner and outer circumferential side edge parts of tapered circumference in a truncated cone cylindrical body fitted to the seat face of head part of disc screw. CONSTITUTION:An inner circumferential cylindrical part 11 composed of a truncated cone cylindrical body forming an inner circumferential side of a small diameter and an outer circumferential side cylindrical part 12 forming an outer circumferential part of a large diameter are set up with a thin metal plate to form an integrated truncated cone cylindrical body. A swelling part 16 protruding in the shape of curvature is formed inwardly on the outer circumferential side cylindrical part 12, that is on the circumferential part thereof except an outer circumferential side circumferential edge part 15. With this arrangement the decrease in strength of fastening caused by degrading due to corrosion can be prevented without damaging the fastened part of member to be fastened and the initial force of spring can be maintained even for a long time of use.

Description

[Detailed Description of the Invention] [Object of the Invention] a) Industrial Application Field The present invention is used by being attached to a countersunk screw having a truncated conical head bearing surface, and is particularly suitable for use in vibrations, shocks, etc. This invention relates to an improvement of a dish-shaped spring washer suitable for fastening in places where it is easy to loosen.

b) Prior Art Conventionally, as this type of disc-shaped spring washer, there has been a disc-shaped disc-shaped washer with teeth for a long time, and later improved disc-shaped spring washers, such as the disc-shaped spring washer disclosed in Japanese Utility Model Publication No. 47-35168. etc.

As shown in FIG. 5, the toothed dish-shaped washer 1 is formed into a truncated conical cylinder with petal-shaped teeth 2 on the outer circumferential side of the large diameter by punching and forming a thin spring metal plate. . ``This dish-shaped washer 1 has a small-diameter inner circumferential side that is a head seat surface of a countersunk screw and a tapered circumferential surface that fits the mold hole of the member for tightening, and the tooth profiles 2 are each twisted in the same direction. At least a part of the edge of the screw is protruded inward from the head bearing surface of the countersunk screw, and the other part protrudes outward from the mold hole of the tightening member, thereby imparting a spring action and a rotation prevention function. It is something that

However, when tightening the members to be fastened,
When this toothed countersunk washer 1 is attached to a countersunk screw and screwed into the screw hole of a member to be fastened, the tooth profile 2 will be painted over the head seat surface of the countersunk screw and the hole in the member. Cause damage such as peeling off the membrane. For this reason, the fastening strength is reduced due to deterioration due to corrosion, and since the tooth profile 2 has a large amount of deflection, it is likely to be permanently deformed beyond the elastic deformation range, resulting in the problem that the initial function cannot be maintained during long-term use.

Therefore, in order to improve the problems of the dish-shaped spring washer 1, the dish-shaped spring washer 3 (
(See the same bulletin for details) was proposed. This dish-shaped spring washer 3 is a truncated conical cylinder with an inner diameter hole 4 on the inner circumferential side that is almost a perfect circle and a tapered circumferential surface that gradually increases in diameter toward the outer circumferential side. It is formed in a continuous state with no tooth profile.

The circumferential surface of the disc-shaped spring washer 5 protrudes inward from a perfect reference circle 6 at a plurality of first locations 5, and at a plurality of second locations 7 located between the first locations 5. It protrudes outward from the perfect reference circle 6, and its cross section is deformed into a wave shape. The amount of deformation is greatest at the edge on the outer circumferential side, but even if the maximum deformation amount is 8, the amount of deformation gradually decreases toward the inner circumference within the plate thickness and converges to the inner diameter of a perfect circle 4.

Further, if the opening angle of the truncated cone cylindrical body based on the reference circle 6 is set to an opening angle θ that approximately matches the head bearing surface angle of the flat head screw A, the tapered surface 5a of the first portion 5 is the flat head screw A. At an angle (θ-α) slightly smaller than the head seat angle, the second point 7
The tapered surface 7a is formed at an angle (θ+α) slightly larger than the head seat angle of the countersunk screw (see FIG. 7), thereby providing a spring action and a rotation prevention function.

C) Problem to be Solved by the Invention Therefore, as shown in FIG.
When the opening angle is different from the above-mentioned opening angle, the following problem occurs.

That is, when the countersunk screw A is tightened, the inner corner 5 formed at the outer peripheral edge of the bellows spring washer 3 at the first location 5
b is pressed against the head seat of the countersunk screw A, and at the second location 7, the outer corner 7b is slid into pressure contact with the mold hole of the tightening member C, and the head seat of the countersunk screw A and the tightening This damages the mold hole of member C and causes deterioration due to corrosion.

Therefore, the present invention provides a dish-shaped spring washer that can solve this problem, and in particular, a dish-shaped spring washer that prevents damage to a countersunk screw or a member to be fastened by the outer peripheral edge of a truncated conical cylindrical body having a tapered peripheral surface. The purpose is to provide shaped spring washers.

[Structure of the invention]

a) Means for Solving the Problems The gist of the present invention is to have a cross-sectional shape that is made of a spring metal thin plate, has a fitting hole in the center into which a countersunk screw is fitted, and has a cross section that fits the head seat of the countersunk screw. It forms a truncated conical cylindrical body having a tapered circumferential surface with a substantially perfect circular surface, and an inwardly curved inner circumferential surface is formed on the inner circumferential surface between the inner circumferential edge and the outer circumferential edge of the tapered circumferential surface. This is a dish-shaped spring washer in which a plurality of bulging portions that bulge out to provide spring force and a rotation prevention function are formed to protrude in a circumferentially spaced manner and face each other at intervals.

b) Examples The present invention will be explained below based on the examples shown in FIGS. 1 to 4.

The disc-shaped spring washer 10 has an inner cylindrical portion 11 formed of a truncated conical cylindrical body forming an inner periphery with a small diameter, as shown in FIGS. 1 and 2.
and an outer circumferential side cylindrical portion 12 formed of a truncated conical cylindrical body forming the outer periphery of the large diameter, which are integrally formed into a truncated conical cylindrical body by a thin metal plate with spring properties.

The inner peripheral side cylindrical part 11 has a taper angle θ with respect to the shaft center so as to match the head bearing surface A0 of the countersunk screw A and the mold hole C□ of the member C for tightening (approximately 45 degree), and is formed to approximately 1/2 to 1/3 of the height h of the entire washer, and the cross section of the inner circumferential side cylindrical portion 11 is approximately a perfect circle. In the case of a washer-integrated screw in which the washer 10 is pre-assembled into the countersunk screw A, the inner diameter hole 13 of the inner circumferential side cylindrical portion 11, which is a fitting hole portion for fitting into the neck of the countersunk screw, is used for screw rotation. It is formed to be larger than the diameter Φ1 and smaller than the outer diameter Φ2 of the screw. In addition, in the case of a screw with a built-in washer, in order to prevent the inner circumferential edge 14 of the washer from rotating and falling off when screwed into the trough (neck) A2 of the screw, the inner circumferential edge 1
4 is cut and formed parallel to the axis. In addition, in the case of a washer manufactured separately from the countersunk screw and attached later, the outer diameter is larger than the outer diameter Φ2 of the screw.

The outer cylindrical portion 12 has a portion on the circumferential surface excluding the outer periphery 15 that is located on the inside with respect to the extension line of the tapered circumferential surface of the inner cylindrical portion 11 (on the head seat side of the countersunk screw). A plurality of (four in this embodiment) bulges 16 that protrude in a curved shape are formed to face each other at intervals in the circumferential direction.

Therefore, the intermediate portion where the bulging portion 16 is not formed has a tapered circumferential surface that is an extension of the tapered circumferential surface of the inner cylindrical portion 11 . Further, the outer circumferential edge portion 15 on which the bulging portion 16 is not formed has a tapered circumferential surface whose cross section is approximately a perfect circle.

This deformed portion is processed by pressing the outer circumferential side cylindrical portion 12 from the outside into the truncated conical cylindrical body 18 having a tapered curved surface and having a perfect circular cross section so as to recess inward. Make it. Note that the degree of bulge d can be arbitrarily set so as to obtain a desired spring force.

When the above-described dish-shaped spring washer 10 is attached to the countersunk screw A and the member C is fastened to the member B to be fastened, the bulged portion 16
is on the head bearing surface A0 side of the countersunk screw A, and the outer surface 17 of the tapered circumferential surface is in contact with the circular hole C□ of the tightening member C, respectively, between the countersunk screw A and the tightening member C. be mediated. and,
When the countersunk screw A screwed into the screw hole B1 of the fastened member B is tightened in this state, the inner corner 15a of the outer peripheral edge 15 slides into the head seat surface A of the countersunk screw A. First, since the outer surface 17 of the tapered peripheral surface is in surface contact with the circular hole C1, the outer corner 15b of the outer peripheral edge 15 is also tightened by the circular hole C of the member C.
It does not come into sliding contact with 1. Therefore, when fastening or removing, the countersunk screw A and the member C are tightened by the bellows spring washer 10.
Since the curved portion of the bulging portion 16 exerts a strong spring force, the initial fastening force can be maintained for a long period of time.

〔Effect of the invention〕

As is clear from the above-mentioned embodiments, in the dish-shaped spring washer of the present invention, the inner corner formed at the edge of the outer peripheral edge is the head bearing surface of the countersunk screw, and the outer corner is the tightening member. Since the members are configured so that they do not slide into the respective circular holes, the countersunk screws and tightening do not damage the members during fastening or removal, and it is possible to prevent the fastening strength from decreasing due to deterioration due to corrosion.

In addition, the curved bulge that protrudes toward the head seat of the countersunk screw exerts a strong spring force and the amount of deflection is small, so the elastic deformation area is large and permanent deformation is difficult to occur, making it suitable for long-term use. Can maintain spring force.

[Brief explanation of the drawing]

Fig. 1 is an overall plan view of a disc-shaped spring washer according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view taken along the line
The figure shows the assembly condition of the same dish-shaped spring washer.
Fig. 4 is an enlarged longitudinal sectional view taken along the line ■-■ in Fig. 1, and Fig. 5 is an enlarged longitudinal sectional view taken along the line ■-■ in Fig. FIG. 6 is an overall front view of a toothed dish-shaped spring washer, FIG. 6 is an overall plan view of another conventional dish-shaped spring washer, and FIG. FIG. [Explanation of symbols] 10... Belleville spring washer 11... Inner peripheral side cylindrical part 1
2...Outer cylindrical part 14...Inner edge 15a...Inner corner 16...Bulging part 17...Outer surface 18 of tapered circumferential surface...Truncated conical tube Shape A... Flat head screw B... Member to be fastened C... Tightening is done on member Φ1... Thread rolling diameter θ... Taper angle 13... Inner diameter hole 15... Outer circumferential side Peripheral edge 15b...Outer corner 80...Head seat surface B□...Screw hole C1...Circular hole Φ2...Outer diameter of screw

Claims (1)

[Claims] A truncated conical cylinder made of a thin spring metal plate, with a hole in the center into which a countersunk screw is fitted, and a tapered peripheral surface with a cross section that fits the head seat of the countersunk screw. A plurality of inwardly curved bulges are provided on the inner circumferential surface between the inner circumferential edge and the outer circumferential edge of the tapered circumferential surface to provide a spring force and a rotation prevention function. The bulge is
A dish-shaped spring washer characterized by having opposing protrusions formed at intervals in the circumferential direction.