JPH0126931Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a mechanical seal used as a shaft sealing device for the rotating shaft of various devices, and in particular to a mechanical seal that is used as a shaft sealing device for the rotating shaft of various devices. This is a suggestion for improvement.

[Conventional technology]

Traditionally, it has been used as the third type of mechanical seal.
There is something like the one shown in the figure. To explain its structure, the mechanical seal, which is designated as a whole by reference numeral 1, has a rotating shaft 2 that is rotated by a drive source (not shown).
A mating ring 3 is a rotating ring that is airtightly fitted and fixed on the outer circumference of the rotating shaft 2 and rotates according to the rotating shaft 2, and a mating ring 3 is airtightly fitted and fixed on the inner circumference of the shaft hole of the equipment housing 4 that is a non-rotating member. a rigid annular retainer 5;
It consists of a resin seal ring 7, which is a fixed ring, which is airtightly attached to the annular stepped portion 5' of the retainer 5 through a packing 6, and the seal ring 7 has one end attached to the rear surface of the retainer 5. It is elastically pressed in the axial direction by a spring 8 carried by the annular step 5', and its front end surface slides closely against the opposing end surface of the mating ring 3, and the sliding seals the fluid to be sealed. There is. Further, the seal ring 7 has a required number of notches 9 formed on its outer circumference that extend in the axial direction, and correspondingly, protrusions 10 protruding from the inner circumference of the stepped portion 5' of the retainer 5. It is engaged so as to be movable in the axial direction, and is prevented from rotating in the circumferential direction. As shown in the side cross section of FIG. The inner diameter end surface 10' is formed in the shape of a circumferential surface constituting a part of the circumferential surface concentric with the annular retainer 5, or in the shape of a plane that is in contact with the circumferential surface.

[Problem that the invention attempts to solve]

In the above configuration, the mating ring 3 rotates together with the rotating shaft 2, and the seal ring 7 does not rotate following the direction of the arrow A in FIG. 4 due to the sliding torque caused by sliding with the mating ring 3. In this case, the sliding torque varies depending on the lubrication conditions of the sliding surface, but the variation in the torque is quite large, and vibrations accompanying the driving of the equipment are added, so the protrusion of the retainer 5 at the notch 9 of the seal ring 7 Part 10
The abutment surface 9' gradually wears out. As the wear progresses, the inner diameter end surface 10' of the protrusion 10
5 forms a peripheral surface concentric with the retainer 5 or a plane in contact with the retainer 5, so as shown in FIG.
2, and comes into close contact with the entire surface. Therefore, the retainer 5 and the seal ring 7
Since the relative movement in the axial direction of the mechanical seal 1 is inhibited and the elastic pressing function and buffering function of the spring 8 are impaired, there is a problem in that the sealing performance of the sliding portion of the mechanical seal 1 is significantly reduced.

In view of these problems, the present invention aims to provide a mechanical seal that can maintain the reliability of the seal even if the notch of the fixed ring wears out due to long-term use.

[Means for solving problems]

To achieve this objective, the present invention provides a mechanical seal having a structure in which a fixed ring that is in sliding contact with a rotating ring that rotates together with a rotating shaft is hermetically fixed to the inner periphery of a housing shaft hole via an annular retainer.
The inner diameter end surface of a protrusion protruding from the inner periphery of the retainer for axially movable engagement with the axially extending notch formed on the outer periphery of the fixed ring is a rising surface of the protrusion. The radial width of the notch portion is inclined such that it becomes larger on the side where it collides with the rising surface of the notch portion.

[Effect]

Therefore, even if the rising surface of the notch that comes into contact with the protrusion is worn out due to long-term use, the protrusion will not come into contact with the outer periphery of the worn part, which forms a substantially circumferential surface formed by the wear. Since this occurs only at the acute-angled inner diameter edge of the rising surface, the contact area is extremely small.

〔Example〕

An embodiment of the mechanical seal according to the present invention will be described below with reference to the drawings.

First, in FIG. 1, reference numeral 21 denotes a rigid annular retainer that is airtightly fitted and fixed to the inner periphery of a non-rotating equipment housing, and 22 denotes the retainer 2.
This is a resin seal ring that is a fixed ring installed in the annular step portion 23 of the first embodiment. A required number of protrusions 24 (only one is shown in the figure) protrudes in the inner radial direction and extends in the axial direction on the inner periphery of the annular stepped portion 23 of the retainer 21, and on the other hand on the outer periphery of the seal ring 22. A notch 25 extending in the axial direction is formed at a portion corresponding to the projection 24, and the loose fit between the notch 25 and the projection 24 allows the retainer 21 and the seal ring 22 to move in the circumferential direction. They engage with each other and are movable relative to each other in the axial direction. Furthermore, the inner diameter end surface 26 of the protrusion 24
is a rising surface 2 that is on the rear-dorsal side with respect to the rotation direction (direction of arrow A) of the mating ring (not shown).
7 is larger than the rising surface 27' on the other side,
In other words, the inner diameter end face 26 and the rising face 27
It is slanted so that the angle it makes with is an acute angle (less than 90°).

In the above configuration, as the mechanical seal is used for a long period of time, the notch 25 is damaged due to bumps and friction caused by fluctuations in sliding torque and vibrations of equipment.
Even if the contact surface 28 of the protrusion 24 with the rising surface 27 is worn out and the wear progresses as shown in FIG. Therefore, the contact of the protrusion 24 with the outer periphery 29 of the worn part is at the inner diameter edge 2.
7", and the contact area is extremely small. In addition, the acute-angled inner diameter edge 27" has the effect of abrading the outer periphery 29 of the wear portion, so that the inner diameter end surface 26 of the protrusion 24 and the seal ring Since the outer periphery 29 of the worn part 22 does not come into close contact with each other, and a small gap 30 is formed between the two, wear powder is easily discharged.

[Effect of idea]

As described above, in the present invention, the inner diameter end surface of the protrusion of the retainer is inclined and one end is formed at an acute angle, so that the inner diameter end surface of the protrusion comes into contact with the outer periphery of the worn part of the notch of the fixed ring. The area is minimized to prevent close contact between the retainer and the fixed ring, thereby preventing deterioration in sealing performance due to inhibition of relative axial movement between the retainer and the fixed ring.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of the main part showing an embodiment of the present invention, Fig. 2 is a side sectional view of the main part showing the state of wear in the same embodiment, and Fig. 3 is a half-section showing an example of a general mechanical seal. 4 is a front sectional view, FIG. 4 is a side sectional view of a main part showing a conventional example, and FIG. 5 is a side sectional view of a main part showing a state of wear in the conventional example. 21...Retainer, 22...Seal ring, 2
3...Annular step portion, 24...Protrusion, 25...Notch, 26...Inner diameter end surface, 27, 27'...Rising surface, 27''...Inner diameter edge, 28...Contact surface, 29...
...Outer circumference of worn part, 30...Small gap.

Claims (1)

[Scope of utility model registration request] A mechanical seal that is used as a shaft sealing device for a rotating shaft and has a structure in which a fixed ring that is in sliding contact with a rotating ring that rotates together with the rotating shaft is airtightly fixed to the inner periphery of a housing shaft hole via an annular retainer,
The inner diameter end surface of a protrusion protruding from the inner periphery of the retainer for axially movable engagement with the axially extending notch formed on the outer periphery of the fixed ring is a rising surface of the protrusion. A mechanical seal characterized in that the radial width of the notch is inclined such that it becomes larger on the side where it collides with the rising surface of the notch.