JPH0131816Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention relates to a resonance prevention bellows in a mechanical seal.

<Prior Art> In mechanical seals, a bellows is sometimes used to press the seal and the sealing ring.
Metal bellows are usually used as the bellows, but conventionally there has been a problem in that they resonate with the vibrations of the machine and vibrate in the axial, radial, or torsional direction.

In order to prevent this resonance, a structure is known in which, as shown in FIG. 4, a balance weight 51 is interposed in the middle of a bellows 50 to change its natural frequency to prevent resonance. However, in this case, there is a drawback that the free length becomes longer by the amount of the balance weight 51. Further, since the balance weight 51 is attached by welding, attachment and detachment are troublesome, and it is virtually impossible to arbitrarily change the weight. Therefore, there was a drawback that it was difficult to obtain a sufficient resonance prevention effect. Furthermore, since the length in the axial direction becomes long, it is difficult to achieve axial center accuracy, which has the disadvantage of poor workability.

Also, as shown in Fig. 5, there is a cup 54 on the bellows.
There is also known a structure in which a ring-shaped damper 52 is attached inside the bellows 50 via a spring 53, and the vibration of the bellows 50 is regulated by the damper 52. However, in this structure, since the bellows 50 is in contact with the damper 52,
There is a drawback that the bellows 50 wears out and the pressing force of the bellows 50 changes. Further, since the bellows 50 is in contact with the damper 52, the movement of the bellows 50 in the axial direction is inhibited, which impairs the sealing performance. Furthermore, since it requires a cup 54 and a spring 53, it cannot be installed in a place where the inner diameter of a stuffing box such as a pump is small.

<Summary of the invention> The present invention was made to improve the above-mentioned conventional drawbacks, and its basic feature is that a two-split ring of a predetermined weight is fitted to the top of the approximately central portion of the outer periphery of the bellows. It is something to do. Such a split ring is easy to install and remove, and the bellows can be easily adjusted to a natural frequency that does not cause resonance.

<Example> An example of the present invention will be described below based on the drawings.

In FIG. 1, the bellows 1 presses the driven ring 21 toward the rotating ring 22 and seals it at the same time, eliminating the need for sealing between the driven ring 21, retainer 23, and casing Y, and allowing the driven ring 21 to move freely. ing. The bellows 1 is composed of a bellows main body 10 and a resonance prevention ring 11 fitted around the outer periphery of the bellows main body 10. As shown in FIG. 3, the resonance prevention ring 11 is divided into two halves, and a fastening band 14 is attached to a fastening groove 15 formed on the outer periphery of the ring to maintain the integral ring shape. By configuring it in two parts in this way, it becomes extremely easy to attach and detach the resonance prevention ring 11.

The resonance prevention ring 11 is fitted at one top of the bellows body 10, and is in contact with the bellows body 10 only at this one top. In this embodiment, as shown in FIG. 2, a protrusion 12 is formed on the inner periphery of the resonance prevention ring 11, and a fitting groove 13 is provided in the protrusion 12 so that the top portion of the bellows body 10 is fitted therein. The weight of the resonance prevention ring 11 may be determined depending on the usage conditions and how much the natural frequency should be in order to prevent resonance. Further, since the resonance prevention ring 11 is easy to attach and remove, it is also possible to prepare a plurality of resonance prevention rings 11 and replace them as appropriate depending on the usage conditions.

As described above, in the bellows 1 of the present invention, its natural frequency can be easily changed by changing the weight of the resonance prevention ring 11, and resonance can be effectively prevented. Additionally, it does not have the disadvantage of having a long free length like conventional balance weights, and the axial accuracy can be maintained at the same level as normal bellows. Further, since the bellows body 10 and the anti-resonance ring 11 are in contact with each other only at one top, there is no problem such as wear of the bellows body 10 or inhibition of the bellows body 10 from following. Furthermore, since the spring 53 and cup 54 are not required, it can be installed in a narrow space such as inside an existing pump.

<Effects of the invention> As explained above, according to the resonance prevention bellows of the invention, its natural frequency can be changed as appropriate depending on the usage conditions, so resonance with vibrations of the machine body can be effectively prevented. There is.

[Brief explanation of the drawing]

Fig. 1 is a half-sectional view showing one embodiment of the present invention, Fig. 2 is a partially enlarged view thereof, Fig. 3 is a perspective view of a resonance prevention ring, and Figs. 4 and 5 are illustrations of the prior art. be. 1: Bellows, 10: Bellows body, 11: Resonance prevention ring, 12: Projection, 13: Fitting groove, 1
4: Fastening band, 15: Fastening groove, 21: Driven ring,
22: Rotating ring, 23: Retainer, 50: Bellows, 51: Balance weight, 52: Damper, 5
3: Spring, 54: Cup.

Claims (1)

[Scope of utility model registration request] A resonance-preventing bellows in a mechanical seal, characterized in that a two-split ring of a predetermined weight is fitted to one top of the substantially central portion of the outer periphery of the bellows.