JPH0128384Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to shaft sealing technology, and more specifically to a mechanical seal having a structure in which airtightness between a shaft and a seal ring is maintained using bellows-shaped packing. Regarding the improvement of

[Conventional technology]

BACKGROUND ART Conventionally, mechanical seals shown in FIGS. 7 and 8 have been known as mechanical seals used in various devices to prevent leakage of internal fluid. Among these, the rotary mechanical seal shown in FIG. 7 is a non-rotating floating seat 3 that is airtightly fitted and fixed to the inner periphery of the stepped portion of the shaft hole of the housing 1 via a buffer rubber 2 having an L-shaped cross section. On the other hand, the seal ring 5, which is fitted onto the shaft 4 and rotates together with the shaft 4, slides closely to prevent leakage of fluid inside the machine at the sliding portion 6.
The seal ring 5 has one end 7a tightly fixed to the rear surface 5a of the seal ring 5 by an annular metal case 8, and the other end 7b tightly crimped to the outer peripheral surface of the shaft 4 by a drive ring 9. A bellows-shaped packing 7 made of rubber material maintains airtightness between the shaft 4 and the packing 7, a drive ring 9, an engagement mechanism 10 between the drive ring 9 and the case 8, the case 8, Case 8
The rotational torque of the shaft 4 is transmitted through the engagement mechanism 11 between the shaft 4 and the seal ring 5, and the coil spring 1 is elastically loaded between the spring retainer 12 fixed to the outer periphery of the shaft 4 and the case 8.
3 in the axial direction, and is brought into sliding contact with the floating sheet 3 with an appropriate surface pressure.

Furthermore, the stationary mechanical seal shown in FIG.
A non-rotating seal ring 5' supported on the housing 1 side closely slides against a floating seat 3' which is airtightly fitted onto the inner periphery of the stepped portion of the shaft 4 via a buffer rubber 2' and rotates together with the shaft 4. By doing so, the leakage of fluid inside the machine is prevented at the sliding portion 6', and the seal ring 5' has one end 7'a
The seal ring 5' is tightly fixed to the rear surface 5'a of the seal ring 5' by a metal case 8', and the other end 7'b is hermetically fitted to the inner periphery of the stepped portion of the single shaft hole of the housing via a buffer rubber 15. The bellows-shaped packing 7' is closely fixed to the inner side of the outer cylinder 16 by the inner cylinder 17, so that airtightness between the housing 1 and the housing 1 is maintained.
Inner cylinder 17 and case 8' crimped to the inner periphery of outer cylinder 16
Rotation is prevented by an engagement mechanism 10' between the case 8' and the seal ring 5', and an engagement mechanism 11' between the case 8' and the seal ring 5'.
Further, it is pressed in the axial direction by a coil spring 13' elastically mounted between the inner cylinder 17 and the case 8', and is brought into sliding contact with the floating seat 3' with an appropriate surface pressure.

[Problem that the invention attempts to solve]

However, among the above-mentioned mechanical seals, the one having the configuration shown in FIG. 7 has members such as the coil spring 13 and the spring retainer 12 separated from the seal ring 5 before installation, making management complicated. The disadvantage is that the workability during installation is also poor. In addition, the configuration shown in FIG. 8 includes non-rotating side structural members (seal ring 5', bellows packing 7', case 8', coil spring 13', inner cylinder 17, and outer cylinder 16).
Since the seals form a single assembly, the drawbacks of the mechanical seal shown in FIG. 7 are eliminated; however,
Since the coil spring 13' does not extend almost to its free length before installation, the bellows-shaped packing 7' is deformed so as to be fully extended in the axial direction. If left in such a state for a long period of time, the neck 7'c etc. will undergo a particularly large degree of deformation.
A new problem arises in that numerous cracks occur in the portion 7'c due to the so-called ozone deterioration phenomenon.

[Means for Solving the Problems] The present invention has been made to solve the above problems. That is, the airtightness between the seal ring and the rotating side or non-rotating side member can be maintained at one end. This is done by a bellows-shaped packing whose other end is tightly fixed to the rear part of the seal ring by an annular case, and whose other end is tightly fixed to the rotating side or non-rotating side member, and the pressing force against the seal ring is In a mechanical seal having a structure in which a coil spring is elastically loaded between a spring retainer fixed to a side or non-rotating side member and the case, one of the spring retainer and the case has a hook-shaped tip. One of the engaging claws is provided with a groove, and the other is formed with a groove portion that engages with the engaging claw, and the extension limit of the coil spring is regulated by the engagement of the two.

[Effect]

According to the present invention, each member such as the seal ring, bellows packing, case, coil spring, and spring retainer forms one assembly by engaging the case and the spring retainer, and in this assembly, the coil spring Since the extension limit of the bellows packing is limited by the case and the spring retainer to be somewhat longer than the installation length, the amount of deformation of the bellows packing is limited even before it is installed on the shaft seal. Therefore, it acts to suppress the occurrence of cracks due to ozone deterioration, etc.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows the installed state of one embodiment, in which a non-rotating floating seat 23 is airtightly fitted and fixed to the inner periphery of the stepped portion of the shaft hole of the housing 21 via a buffer rubber 22 having an L-shaped cross section. On the other hand, the rotary side seal ring 25, which slides closely with an appropriate surface pressure, has one end 26a tightly fixed to the rear surface 25a of the seal ring 25 by a metal case 27, and the other end 26b. The shaft 24 has a bellows-shaped packing 26 made of a rubber material that is crimped and fixed between the inner circumferential surface of the axial portion 29 formed on the inner diameter of the spring retainer 28 and the outer circumferential surface of the shaft 24.
The case 27 and the spring retainer 28 are kept airtight, and are urged in the axial direction by a coil spring 30 that is elastically loaded between the case 27 and the spring retainer 28. As shown in FIG. 2, the spring retainer 28 is provided with a plurality of equally spaced engaging claws 31 extending in the axial direction and having hooks 31' bent inwardly at the tips thereof, and projecting from the case. Recessed grooves 33 corresponding to the engaging claws 31 are equally spaced in the inner diameter axial direction portion 32 of the groove 27, and the bottom portion 3 of the groove 33 is recessed.
3' has a slit 34 that engages with the hook 31'.
is drilled. In the case 27, reference numerals 35 are concave steps that engage with engagement notches 36 formed at equal intervals on the outer peripheral surface of the seal ring 25, and 37 are caulking claws for preventing the seal ring 25 and the bellows-shaped packing 26 from coming off. be.

Here, as shown in FIG. 3, the inner diameter D ₁ of the hook 31' is set smaller than the outer diameter D ₂ of the recessed groove bottom 33'. When the coil spring 30 is inserted into the inner axial portion 32 or the outer circumferential side of the engaging claw 31 of the spring retainer 28, and the members 27 and 28 are pressed against each other and brought close to each other in order to compress the coil spring 30, as shown in FIG. ni hook 3
1' rides on the outer periphery of the depressed groove bottom 33' and the entire hook 31 is flexibly deformed toward the outer diameter side, and when the end of the hook 31' reaches the end 34' of the slit 34, As shown in FIG. 5, the engaging pawl 31 elastically returns to the inner diameter side, and the hook 31'
4 and interact with each other. This engagement functions to prevent the case 27 and the spring retainer 28 from rotating relative to each other, and also functions to restrict the extension limit of the coil spring 30. That is, the distance between the stepped portion 27' of the case 27, which one end of the coil spring 30 abuts, and the spring retainer 28, which the other end abuts, is as follows when the hook 31' and the slit end 34' are in abutment. The maximum length is l ₂ , and the length of this l ₂ (coil spring 30
(extension limit) is the length in the installed state shown in Figure 1.
The dimensions of each part are set so that the actual size is approximately 1 to 3 mm slightly larger than l ₁ (installation length).

Therefore, in the above embodiment, the seal ring 25, the bellows packing 26, and the case 2
7. In addition to being able to handle the spring retainer 28 and the coil spring 30 as one assembly, the amount of deformation of the bellows-shaped packing 26 is small due to the regulation of the expansion limit of the coil spring 30, so that the assembly can be used as a shaft sealing part. Even if the rubber material of the packing 26 is left unattached for a long period of time, ozone deterioration of the rubber material of the packing 26 can be suppressed.

Note that the shape of the hook 31' is not limited to that in the above embodiment; for example, it may be shaped like a fountain pen clip as shown in FIG. It may also be configured to be provided on the retainer side. Furthermore, although the above-mentioned embodiment is an example in which the present invention is applied to a rotary type mechanical seal, it is of course possible to apply the present invention to a stationary type mechanical seal.

[Effect of idea]

As mentioned above, the mechanical seal of the present invention is easy to handle and install by forming each member on the seal ring side into an integral assembly, and the expansion limit of the coil spring in the assembly is restricted. Because of this, the amount of deformation of the bellows-shaped packing is small, and therefore aging phenomena such as ozone deterioration of the rubber material do not progress easily even if left for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a half-cut sectional view showing an installed state of one embodiment of the mechanical seal of the present invention, FIG. 2 is a perspective view of the main parts, and FIGS. 3 to 5 are explanatory diagrams of the same assembly operation.
Fig. 6 is a half-cut sectional view of the main part showing another modification;
FIG. 8 and FIG. 8 are half-cut sectional views showing a state in which a conventional mechanical seal is installed. 21... Housing, 23... Floating seat, 24... Shaft, 25... Seal ring, 26... Bellows type packing, 27... Case, 28... Spring retainer, 30... Coil spring, 31... Engaging claw, 31'... hook, 33... recessed groove, 34... slit, 35...
...Concave stepped portion, 36...Engagement notch.

Claims (1)

[Scope of utility model registration request] Airtightness between the seal ring and the rotating side or non-rotating side member is maintained by having one end tightly fixed to the rear of the seal ring by an annular case, and the other end tightly fixed to the rotating side or non-rotating side member. The seal ring is pressed by a coil spring elastically loaded between the case and a spring retainer fixed to the rotating side or non-rotating side member. In this mechanical seal, one of the spring retainer and the case has a hook-shaped hook-shaped tip, and the other has a groove that engages with the hook, and the engagement of the two causes the coil spring to expand. A mechanical seal characterized by a regulated limit.