JP3059911B2 - Bolt assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt assembly used for a fastening part of a machine, an instrument or the like which handles a fluid, and particularly to a fastening part which requires both vibration damping and fluid sealing. The present invention relates to an improvement in a bolt assembly of an anti-vibration washer suitable for use.

[0002]

2. Description of the Related Art Conventionally, a material having a rubber viscoelastic layer on one or both sides of a thin metal plate for the purpose of isolating vibration transmitted from the bolt as a washer used together with the bolt when fastening a machine or a part with the bolt. , Or a laminated anti-vibration washer made by laminating a plurality of laminated materials by gluing this material together and mechanically caulking with claws cut and raised in the thickness direction. In such a case, there is known an anti-vibration washer in which rubber viscoelastic layers provided on the uppermost surface and the lowermost surface of the anti-vibration washer are also used as a fluid sealing material (see Japanese Patent Application Laid-Open No. 6-341488). .

FIGS. 13 and 14 show an example in which a bolt assembly to which the above-mentioned anti-vibration washer is assembled is used for fastening a head cover of an automobile. FIG. 13 shows a vibration transmission path from a bolt portion. In FIG. 13, 1 is a fastened portion that generates mechanical vibration, 2 is a fastened portion such as a cover, 3 is a gasket for a fluid seal, and 4 is a gasket for a fluid seal. Bolt with cap for fastening, 4a
Is a bolt shaft, and 4b is a bolt head. As indicated by arrows, the path of vibration generated during machine operation in the fastened portion 1 includes a route for directly transmitting between fastened portions and an indirect transmission route for transmitting through the bolt shaft portion 4a. In this case, the vibration transmission can be cut off by inserting a viscoelastic body such as rubber between the fastened portion and the fastened portion such as the cover. Further, the latter vibration transmission can be prevented by using the above-mentioned vibration-proof washer W.

FIG. 14 shows a fluid path from a bolt portion. In this case, when fluid exists in the machine main body which is fastened by the bolts to which the vibration-proof washers are assembled (e.g., a head cover of an automobile), when the machine is operating, the fluid is transmitted through the bolts 4 by mechanical vibration as indicated by arrows. In some cases, the rubber viscoelastic layer is provided at least on the lowermost surface of the washer W. However, according to the structure in which the rubber viscoelastic layer is provided at least on the lowermost surface, fluid leakage from between a fastened portion such as a cover and the washer is prevented. It is possible to do.

[0005]

SUMMARY OF THE INVENTION The above-mentioned JP-A-6-341
The anti-vibration washer described in Japanese Patent No. 488 has the above-mentioned features, but has the following problems. (1) Since the laminated anti-vibration washers have a configuration in which cut-and-raised claws (usually four claws are provided at the same central angle portion) in the thickness direction of the laminated material are mechanically caulked, When caulking, the surface pressure is not uniformly applied to the periphery of the nail, and undulation occurs. This undulation makes it difficult to secure a seal line for a washer inner diameter portion (a portion to be fastened such as a washer / bolt and a washer / cover) which is indispensable for a fluid seal. That is, there is a difference in the surface pressure distribution of the seal line between the portion having the claw hole and the portion having no claw hole. Further, as shown in FIG. 15, the anti-vibration washer W is obtained by caulking and integrating a plurality of materials with the cut-and-raised claw pieces instead of bonding and laminating. There is a danger that a gap will be formed, and the fluid that has passed between the bolt and the washer will flow into this layer and leak out to outside through the claw portion of the washer.

(2) Normally, a bolt hole of a machine or the like is chamfered in order to avoid burrs of the bolt hole itself.
Due to the effect of this chamfering, even if a structure necessary to secure a seal line is adopted on the inner diameter side of the lowermost surface of the anti-vibration washer, the fluid flows from the chamfered portion to the washer cut and raised, and flows into the claw portion,
It may leak out. In order to solve the above-mentioned problem, measures such as changing the shape of the cut-and-raised nail of the washer and the position of the nail can be considered, but it is difficult to secure a seal line depending on the type of chamfering (chamfering is large). This is not a universal measure. Further, the surface roughness and flatness of the washer seated by the machine vary, and the thin rubber layer coated and vulcanized on the washer may not be able to follow the surface, and the capability may be insufficient.

(3) When the bolts and washers are used, for the purpose of reducing the number of steps for assembling the bolts and washers, an attempt is made to reduce the number of steps for assembling the bolts and washers as an assembly. ing.
For example, as shown in FIG. 16, a bulging portion 4c is provided as a part of a falling prevention mechanism (serration) on a part of a shaft portion 4a of the bolt 4, and a washer is press-fitted into the bulging portion 4c to enable assembly. is there. However, this bolt with a drop-out prevention mechanism has a drawback of increasing costs.

[0008]

The object of the present invention is to use a conventional anti-vibration washer as a washer to achieve a high characteristic by repeatedly laminating a metal and a rubber and mechanically caulking. The main object of the present invention is to provide a bolt assembly which can utilize the vibration damping property and the low settling property at the same time as it is, and can surely exhibit the fluid sealing property of the bolt portion, and can be constructed at a low cost.

[0009]

A bolt assembly according to the present invention has a bolt, an anti-vibration washer fitted to the bolt shaft, and a strong fit to the bolt shaft at least at the lower surface portion of the anti-vibration washer. The gist consists of a rubber ring.

As the rubber ring, an O-ring, a △ -ring, a □ -ring or the like is applied according to the shape of the bolt hole. Examples of the material include NBR, fluorine rubber, acrylic rubber, silicone rubber, butyl rubber, urethane rubber, SBR rubber, and the like. In addition, since the cross-sectional dimensions (wire diameter) and inner diameter of the rubber ring differ depending on the target machine, the bolt diameter, the bolt hole diameter, and the chamfered part dimensions are different.
Although it cannot be specified unconditionally, it is sufficient that the following operation is satisfied and the compression ratio at the time of press bonding is 5 to 40%, and it is preferably 20 to 30%.

[0011]

According to the above construction, the vibration isolating washer inserted into the bolt shaft is prevented from falling off from the bolt shaft by the rubber ring firmly fitted to the bolt shaft on the lower surface thereof.
It is kept in the assembled state. In addition, since the rubber ring can be positioned on the claw portion of the vibration isolating washer, the sealing performance of the claw portion is greatly improved. In addition, when the head ring or the like having a chamfered portion is used for a portion to be fastened, the rubber ring that is strongly fitted to the bolt shaft portion does not shift in the radial direction and is positioned concentrically with the chamfered portion. And
At the same time, the lower surface of the anti-vibration washer, the chamfered slope, and the bolt shaft are strongly pressed, so that the fluid is prevented from flowing out from the bolt shaft to the washer.

[0012]

FIG. 1 shows a bolt assembly according to an embodiment of the present invention, FIG. 2 shows its use, and FIG. 3 shows its tightened state. The same or similar members as those in FIGS. 13 to 15 are denoted by the same reference numerals.

1 to 3, reference numeral 1 denotes a fastened portion that generates mechanical vibration, 2 denotes a fastened portion such as a cover, 3 denotes a gasket for a fluid seal, 4 denotes a bolt, and 4a denotes a bolt shaft. , 4b is a bolt head, W is a vibration-proof washer, and a rubber ring R having an O-shaped cross section is strongly fitted to the shaft portion 4a of the bolt 4 at a position in contact with the lower surface of the vibration-proof washer W. ing. By strongly fitting the rubber ring R to the shaft 4a of the bolt 4, the ring itself is firmly held by the shaft 4a, and the vibration-proof washer W fitted to the shaft 4a is It is held by the shaft portion 4a without falling off. Therefore, the bolt, the vibration washer, and the rubber ring R are integrated to form a bolt assembly.

FIGS. 4 to 6 schematically show examples of the structure of the anti-vibration washer W. FIG. 4 is an overall perspective view, FIG. 5 is an exploded side view of a basic unit of the anti-vibration washer, FIG. 6 is a partial side view showing a state in which the basic units are joined together by cutting and raising nail pieces. In the drawings, 11 is a metal plate, 12 is a rubber viscoelastic layer, and 13 is an adhesive layer. Basic unit a ₁ is metal plate 11
Are integrally bonded by an adhesive layer 13 so that the rubber viscoelastic layers are opposed to each other, and have a structure of a constrained vibration damping material. I have. Basic single b ₁ previously formed rubber visco-elastic layer 12 on one surface of the metal plate 11 has a structure of its own unconstrained damping material. Then, the basic units b ₁ and b ₂ are superimposed on the basic unit a _{1 such} that the rubber viscoelastic layer faces each other. Of the basic units b ₁ -a ₁ -b ₁ , the upper unit b ₁ and the intermediate unit b ₁ are interposed. of the single a _1, claw piece 14 undergoes four rectangular cut in the circumferential direction is provided, by pressurizing in a thickness direction superimposing alone b ₁ -a ₁ -b _1, an intermediate layer of a single a ₁ pawl 14 is fitted into the notch opening 15 of the lower single b _1, pawl 14 of the upper layer of a single b ₁ is fitted into the cutout opening made in the cut-and-raised claws of a single a ₁ of the intermediate layer, Simple substance b ₁ −
a ₁ -b ₁ are joined by the fitting action of the claw pieces 14 and are integrated at the joined portions. Here, those anti-vibration washer having a sealing function, of the above structures, all of b ₁ and that forms the rubber visco-elastic layers on both sides of the metal plate, a rubber layer exposed to the outermost surface, It exhibits a sealing function.

When the bolt assembly in which the vibration isolating washer and the rubber ring are integrally formed with the bolt as described above is employed, the following operation and effect can be obtained.

(1) Since the seal line at the bolt hole chamfered portion can be secured concentrically, it is possible to secure the sealing performance at the root without being affected by the shape and structure of the vibration-proof washer. At the same time, accurate positioning of the bolt is possible. As shown in FIGS. 9A and 9B, when the rubber ring R is fitted with play into the bolt shaft portion 4a, the rubber ring R has a holding force on the vibration-proof washer W. No, and it is misaligned with the bolt hole chamfer,
When a part thereof protrudes from the chamfered portion, a phenomenon occurs in which a uniform pressure is not applied and the washer cannot be tightened.
As a result, the sealability at the initial stage cannot be satisfied, not to mention the long-term sealability. In addition, since the washer is displaced and directly hits the bolt, vibration isolation may not be possible. Further, as shown in FIGS. 10A and 10B, when the rubber ring is not used and the vibration isolating washer is used alone, the vibration isolating property of the vibration isolating washer is not changed, but the vibration of the machine body is not changed. It becomes difficult to prevent displacement,
The shaft portion of the bolt may come into contact with a fastened portion such as a cover, and as a result, there may be no reason for the existence of the vibration-proof washer. However, according to the use of the bolt assembly having the above configuration, the above-mentioned disadvantages do not occur at all.

(2) By firmly fitting the rubber ring to the bolt shaft, the bolt and the vibration-proof washer can be integrated, and it is not necessary to provide the bolt with a falling-off prevention mechanism (serration). In addition, the cost of bolt processing can be reduced. At the same time, the pre-assembly can provide a reduction in the work of assembling bolts and washers at the customer. The graph of FIG. 11 shows the effect of the present invention for improving the sealing performance. This graph shows the seal pressure of the fluid according to the tightening torque (pressure when the fluid leaks)
Is measured. The conventional product does not use a rubber ring.

(3) It is possible to prevent the bolt from coming into contact with the bolt hole, and a higher vibration isolation effect can be maintained. FIG. 12 is a graph showing a measurement of a difference in vibration insulation depending on the presence or absence of contact between a bolt and a fastened portion such as a cover, which is one of the secondary effects of the present invention. According to this,
By avoiding contact according to the present invention, it has become possible to greatly improve vibration insulation.

(4) It is effective for positioning of a portion to be fastened such as a cover, and the displacement of the machine body can be prevented.

(5) By integrating the anti-vibration washer with the bolt via the rubber ring, the position of the anti-vibration washer and the rubber ring with respect to the bolt is fixed before mounting, as described above. The rubber ring is positioned on the claw portion of the anti-vibration washer, which causes the sealing performance to deteriorate, because the rubber ring is accurately positioned on the chamfered portion of the bolt hole. Since it is strongly crimped to the portion, the sealing performance of the conventional anti-vibration washer is improved.

FIG. 7 shows another embodiment of the present invention. In this embodiment, the inner diameter of the lowermost layer portion of the vibration-proof washer is increased to form a large-diameter portion, and a rubber ring R is tightly fitted to the bolt shaft portion 4a in a state of being pressed into the large-diameter portion. When a vibration-proof washer is used for an object to be fastened such as a cover having no chamfered portion in the bolt hole, the rubber ring is in the way and the washer cannot be tightened. Therefore, it is naturally impossible to ensure the sealing performance. However, if the bolt assembly according to the above embodiment is used, the above problem is eliminated, and at the same time, the washer and the rubber ring can be integrated.

FIG. 8 shows another embodiment of the present invention. This embodiment is different from the embodiment shown in FIG. 7 in that the inner diameter of the uppermost portion of the vibration-isolating washer is increased to form a large-diameter portion.
a.

According to the above configuration, in addition to the effect of the configuration of FIG. 7, there is an advantage that the sealing performance of the contact surface between the bolt head and the vibration-proof washer W can be ensured. Further, even when the anti-vibration washer is mistakenly turned upside down, the rubber ring can be positioned at the lowermost layer of the washer.

[0024]

As described above in detail, according to the present invention, the characteristics of the conventional anti-vibration washer can be utilized as it is, the fluid sealing property of the bolt portion is surely exhibited, and the configuration can be made at a low cost. A bolt assembly is obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a bolt assembly illustrating one embodiment of the present invention.

FIG. 2 is a side view of the use state of the bolt assembly.

FIG. 3 is a side view of the bolt assembly in a fastened state.

FIG. 4 is a perspective view of an anti-vibration washer.

FIG. 5 is an exploded side view of a basic unit of the vibration washer.

FIG. 6 is a partial side view showing a state where the anti-vibration washer is joined by the cut-and-raised claw pieces.

FIG. 7 is a side view of a bolt assembly showing another embodiment of the present invention.

FIG. 8 is a side view of a bolt assembly showing another embodiment of the present invention.

FIG. 9 is a sectional view of a bolt assembly shown as a comparative example to the present invention.

FIG. 10 shows bolts shown as comparative examples with respect to the present invention.
FIG. 3 is a cross-sectional view of the assembly.

FIG. 11 is a graph showing the sealing performance of the product of the present invention and the conventional product in comparison.

FIG. 12 is a graph showing vibration insulation properties of the product of the present invention and a conventional product in comparison.

FIG. 13 is a cross-sectional view of a mechanical part showing a vibration isolation transmission path from the bolt part in a state where the mechanical part is fastened by a conventional bolt assembly.

FIG. 14 is a cross-sectional view of the mechanical part showing a fluid path from the bolt part in a state where the mechanical part is fastened by the conventional bolt assembly.

FIG. 15 is a side view of a washer portion for explaining a fluid leak caused by the cut-and-raised claw pieces of the vibration-proof washer.

FIG. 16 is a side view of a conventional bolt with a washer preventing mechanism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fastened part which generates mechanical vibration 2 Fastened part, such as a cover 3 Fluid seal gasket 4 Fastening cap bolt 4a Bolt shaft part 4b Bolt head 4c Swelling part W Vibration washer R Rubber ring 11 metal plate 12 rubber visco-elastic layer 13 adhesive layer a ₁ to form a vibration washer, b ₁ basic unit 14 cut and raised claw piece 15 notch opening

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masataka Yoshihara 7-4-40-401, Tatsuta Nishi, Ikaruga-cho, Ikoma-gun, Nara Prefecture (56) References Jikai Sho 60-161714 (JP, U) (58) Field (Int. Cl. ⁷ , DB name) F16B 43/00 F16B 39/26

Claims (3)

(57) [Claims] 1. A bolt, a vibration isolating washer inserted into a bolt shaft portion, and a rubber ring strongly fitted to the bolt shaft portion at least at a portion abutting on a lower surface side of the vibration isolating washer. A bolt assembly, characterized in that: 2. A large-diameter portion formed by increasing the inner diameter of a lowermost layer portion of the vibration-isolating washer, and a rubber ring is strongly fitted to the bolt shaft portion in a state of being pressed into the large-diameter portion.
The bolt assembly according to claim 1. 3. An inner diameter of the lowermost layer and the uppermost layer of the anti-vibration washer is increased to form a large diameter portion, and a rubber ring is strongly fitted to the bolt shaft portion in a state of being press-fitted into each large diameter portion. The bolt assembly of claim 1 in combination.