JPH0448372Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mounting structure for mechanical seals arranged in tandem or double arrangement.

[Conventional technology and its problems]

Conventionally, multiple mechanical seals are arranged in a tandem or double type, and at least some of the components are extrapolated to the shaft in a sequential series building block type from one side in the axial direction, and these parts are extrapolated to the shaft. It is known that the mechanical seal is elastically biased in the removal direction by a biasing force that applies surface pressure to the sliding surface of the seal, but according to this conventional mechanism, the mechanical seal on the retrofit side is disassembled and the mechanical seal is removed simultaneously. The mechanical seal on the side is also stretched by the biasing force, and the biasing force does not work on the sliding surface, resulting in insufficient surface pressure, resulting in a disadvantage that the fluid sealed in the mechanical seal on the first side leaks.

[Means for solving problems]

In view of the above points, the present invention provides a mechanical seal mounting structure that allows the first mechanical seal to maintain its sealing effect even if the retrofit mechanical seal is disassembled.To achieve this purpose,
A sleeve is placed between the retainer that holds the rotating ring of the pre-installed mechanical seal inside the housing shaft hole on the rotating shaft, and the retainer that holds the rotating ring of the retro-installed mechanical seal outside the shaft hole on the rotating shaft. The rear surface of the retainer of the retrofitted mechanical seal is supported by a lock nut screwed onto the outer circumferential surface of the rotating shaft, and the retainer of the retrofitted mechanical seal is supported from the rear inner circumferential surface of the sleeve to the front inner circumferential surface of the retainer of the retrofitted mechanical seal. A key divided into two or more pieces in the axial direction is fitted across both the continuously formed key relief groove and the key groove formed on the outer circumferential surface of the rotating shaft corresponding to the key relief groove, and each divided key is inserted into the key groove. , which is shorter than the difference in length between the keyway and the key clearance groove of the sleeve.

[Effect]

When the key is installed, the key is treated in the same manner as the shaft-side part of the mechanical seal and forms a part thereof. In other words, the first mechanical seal in the housing shaft hole holds the retainer that holds the rotating ring.
The spring that applies pressure to the sliding surfaces of the rotating ring and the stationary ring is pushed in with a sleeve so that it has an installation length that is a predetermined compressed length. In this state, the keyway from the rear end of the sleeve located on the outside of the housing to the outer peripheral surface of the rotating shaft is partially exposed by the difference in length from the key relief groove of the sleeve, and the split key can be inserted from this exposed keyway. By fitting between the key relief groove and the remaining split key, the mechanical seal on the front side is prevented from coming off at the installation length via the sleeve, and the retainer is fixed against the rotating shaft. Rotation is stopped. Then, the retrofitted mechanical seal that is inserted around the shaft is prevented from coming off at a predetermined installation length by a lock nut, and the retainer holding the rotating ring is prevented from rotating with respect to the rotating shaft by the split key. Ru.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

Fig. 1 shows an enlarged view of the shaft seal of an underwater motor. Two sets of mechanical seals 3, 14 arranged in tandem, front and rear, are extrapolated from the right direction in the figure with respect to the rotating shaft 1, and the mechanical seals on the left side are Seal 3 on the front side,
The mechanical seal 14 on the right side is installed later, and lubricating oil for a bearing, which is a liquid to be sealed, is sealed in the inner periphery of the mechanical seal 3 installed first.

The mechanical seal 3 on the advance side is located in the shaft hole of the motor housing 2, and a mating ring 5 is attached to the inner circumference of the case 4, which is bolted to the housing 2 in an airtight manner, so that it can be freely moved in the axial direction and is attached to an O-ring. 6, and the mating ring 5 is biased rightward by a spring 7 and pressed against the seal ring 8. The seal ring 8 is
A rubber cap 11 is held by a retainer 9 fitted to the rotating shaft 1 so as to come into contact with the stepped portion 1a thereof, and protrudes from the retainer 9 into a notch 8a formed at the rear end.
It is engaged with a knock pin 10. Knock pins with rubber caps, including those with the same configuration described later, are made by gluing or baking a rubber material onto the head of a stainless steel knock pin, and due to the elasticity of the rubber cap, it can be made of silicon carbide, cemented carbide, carbon, etc. To prevent chipping and damage of sliding materials made of brittle materials. The rubber cap, which is glued or baked onto the knock pin, does not come off the pin and effectively absorbs the shock at startup. O-rings 1 are installed between the seal ring 8 and the retainer 9 and between the retainer 9 and the rotating shaft 1, respectively.
2 and 13. Although not shown, the case 4 and the mating ring 5 are the case 15 of the mechanical seal 14 on the retrofit side, which will be described later.
Like the mating ring 16, it has a rotation prevention structure using a knob pin with a rubber cap.

The mechanical seal 14 on the retrofit side also has a configuration that substantially overlaps with the mechanical seal 3 on the preinstallation side. That is, a mating ring 16 is located outside the shaft hole of the motor housing 2 and is airtightly supported on the inner periphery of a case 15 that is bolted to the housing 2 in an axially movable manner and via an O-ring 17. A dowel pin 18 with a rubber cap 19 protruding from the case 15 is engaged with a notch 16a formed at the front end of the mating ring 16. The mating ring 16 is urged rightward using a spring (not shown) and pressed against the seal ring 20, similarly to the mating ring 5 of the mechanical seal 3 on the front side.
The seal ring 20 is held by a retainer 21 fitted to the rotating shaft 1, and a knock pin 22 with a rubber cap 23 protruding from the retainer 21 is engaged in a notch 20a formed at the rear end. Seal ring 20
and the retainer 21 are sealed with an O-ring 24.

A sleeve 25 is provided between the retainers 9 and 21.
are airtightly fitted using O-rings 26 and 27, and a knock pin 28 protruding from the tip engages with a notch 9a formed at the rear end of the retainer 9 of the front mechanical seal 3. A locking nut 29 equipped with an O-ring 30 is removably screwed onto the rear end of the retainer 21 of the retrofitted mechanical seal 14 to the threaded portion 1b of the rotating shaft 1, and from the left, a mating ring 5, a seal ring 8, retainer 9, sleeve 26, and retainer 21, which are arranged in series in this order, are positioned in the axial direction against the elasticity of springs 7 of both mechanical seals 3, 14.

In the configuration described above, loosen the lock nut 29 and tighten the mechanical seal 1 on the retrofit side.
When attempting to disassemble 4, the sleeve 25 that should remain on the outer circumference of the shaft and the mechanical seal 3 on the tip side are removed.
components are pushed by the spring 7 and moved to the right, and when the spring 7 is fully extended, the sealing force of the mechanical seal 3 on the front side is lost, causing a situation where lubricating oil leaks. The mounting structure of the present invention further includes the following configuration to prevent this leakage.

That is, a keyway 1c is formed on the circumferential surface of the shaft 1 so as to correspond from the vicinity of the rear end of the sleeve 25 fitted in the proper mounting position to the front half of the retainer 21 of the rear-mounted mechanical seal 14. Two split keys 3 arranged in series in the axial direction in the keyway 1c
1 and 32 are engaged. Key escape grooves 25a, 21 are provided on the inner periphery of the rear end of the sleeve 25 and the inner periphery of the front half of the retainer 21, corresponding to the split keys 31, 32.
a is formed, the total length of the keyway 1c _{is 1} , and the partial length of the keyway 1c that is left exposed on the rear side of the sleeve 25 before fitting the sleeve 25 in the proper position and fitting the retainer 21. ₂ , and the lengths of both split keys 31 and 32 _{are 3} and ₄ , respectively, and are set to satisfy _1≈3 + ₄ , ₂ > ₃ , ₂ > ₄ .

Each component of the pre-attached mechanical seal 3 is attached to the shaft 1.
After fitting the sleeve 26 in the proper position by compressing the spring 7, the two split keys 3
1 and 32 are engaged one by one in the keyway 1c. As a result, even if the force pushing the sleeve 25 is removed, the end surface 25a' of the key escape groove 25a presses against the end surface of the key 31, and the sleeve 25 is prevented from moving in the axial direction. Even if the mechanical seal 14 is assembled and further disassembled, the sealing action of the front mechanical seal 3 can be maintained regardless of this. FIG. 2 shows a jig 33 that is convenient to use when engaging the split keys 31, 32 in the keyway 1c. That is, a cutout window 33a through which the split keys 31 and 32 are inserted is formed in a part of the cylinder that is inserted onto the shaft 1, and the jig 33
is inserted from behind the sleeve 25, and the split keys 31 and 32 are inserted one by one, aligning the notch window 33a with the keyway 1c. When pushing in this sleeve 25 and jig 33 including the components of the first mechanical seal 3, the lock nut 29 is used, and after the split keys 31 and 32 are engaged, the second mechanical seal 14 is attached. The lock nut 29 is once removed from the shaft 1, and the jig 33 is removed.

[Effect of idea]

As explained above, the mounting structure of the mechanical seal of the present invention is such that the split key fitted into the keyway of the rotating shaft prevents the retainers of both the front and rear mechanical seals from rotating relative to the rotating shaft. It also has the function of specifying the pre-installed mechanical seal to a predetermined installation length, so even if the retro-installed mechanical seal is disassembled, the sealing performance of the initial-installed mechanical seal will not be impaired, and the After disassembling the side mechanical seal, if the splitting key is removed, the advance side mechanical seal can be disassembled without disassembling the housing.
Since both mechanical seals can be installed and disassembled from outside the housing, excellent effects such as ease of installation and disassembly are achieved.

[Brief explanation of the drawing]

FIG. 1 is a half-cut sectional view showing a shaft seal portion of an underwater motor using a mechanical seal mounting structure according to an embodiment of the present invention, and FIG. 2 is a perspective view of a mounting jig. DESCRIPTION OF SYMBOLS 1...Rotating shaft, 1a...Step part, 1b...Threaded part, 1c...Keyway, 3...Fixing side mechanical seal, 4, 15...Case, 5, 16...Mating ring, 7 ...Spring, 8,20...
Seal ring, 9, 21...retainer, 10, 1
8, 22, 28... Knock pin, 11, 19, 2
3...Rubber cap, 14...Retrofit side mechanical seal, 21a, 25a...Key escape groove, 25...
...Sleeve, 29...Lock nut, 31, 32
...Division key, 33...Jig, 33a...Notch window.

Claims (1)

[Scope of utility model registration request] Inside the shaft hole of the housing and outside the shaft hole, there are a pair of mechanical seals in which the rotary ring is located on the outside of the stationary ring and slides closely against each other due to the axial biasing force of a spring. A sleeve is interposed between a retainer that holds the rotating ring of the side mechanical seal on the rotating shaft and a retainer that holds the rotating ring of the retrofitted side mechanical seal outside the shaft hole on the rotating shaft, and The back surface of the retainer of the mechanical seal is supported by a lock nut screwed onto the outer circumferential surface of the rotating shaft, and a key clearance groove is formed continuously from the rear inner circumferential surface of the sleeve to the front inner circumferential surface of the retainer of the retrofitted mechanical seal. , fit a key divided into two or more in the axial direction so that it spans both key grooves formed on the outer circumferential surface of the rotating shaft support corresponding to this key relief groove, and insert each divided key into two or more pieces between the key groove and the sleeve. A mechanical seal mounting structure characterized by having a key clearance groove shorter than the difference in length.