JPH07782Y2 - Outside mechanical seal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a mechanical seal for axially sealing a rotary shaft portion of a machine body such as a rotary joint, and in particular, a sealed sliding surface formed by a rotary ring and a fixed ring. The outside mechanical seal in which the leak direction of the fluid to be sealed is the outer diameter direction.

[Conventional technology]

Conventionally, as a typical conventional example of a mechanical seal,
Some have a structure as shown in the figure.

That is, the support ring 5 to which the mating ring 4 as the fixed ring is shrink-fitted is fitted and fixed to the inner diameter portion 1a of the housing 1 of the machine body through the O-ring 3. On the other hand, the case 11 is tightly fitted in the annular recess of the inner diameter of the rotary body 12 attached to the rotary shaft 2 inserted through the inner circumference of the housing 1 and is fastened and fixed by the bolt 13 to form a rotary ring. The seal ring 6 fits inside the case 11 with the O-ring 10.
Is movably supported in the axial direction via a retainer 7 which is integrally engaged with a retainer 7 which is circumferentially engaged with a case 11 by a knock pin 8 and is pressed against the mating ring 4 by a spring 9 in the case 11. ing.

This mechanical seal is intended to seal the high-pressure fluid existing on the inner periphery of the housing 1 side, and the sealing target body A is directed toward the outer diameter side on the sealing sliding surface S formed by the mating ring 4 and the seal ring 6. Because it tries to leak, it is called an outside mechanical seal (outward flow mechanical seal).

[Problems to be solved by the device]

However, in such a conventional outside type mechanical seal, the rotation stop of the seal ring 6 with respect to the case 11 is performed by the engagement of the knock pin 8 implanted in the case 11 and the retainer 7 shrink-fitted in the seal ring 6. It is necessary to increase the wall thickness of the case 11, and therefore the case 11 must be manufactured by turning, and the shape thereof is complicated, which causes a problem of high manufacturing cost.

The present invention has been made in view of such a problem, and its main purpose is to simplify the structure and reduce the cost.

[Means for Solving the Problems]

In order to achieve the above object, an outside mechanical seal according to the present invention includes a rotary ring which is arranged around an axis of a rotary shaft which is inserted through an inner circumference of a housing and which is tightly fitted to a rotary body integrated with the rotary shaft. A cylindrical case having a substantially U-shaped cross section that is tightly fitted to the inner peripheral surface of the end of the housing and is open toward the rotating ring side, and a plurality of protrusions are provided to project from the end of the outer peripheral cylinder of the cylindrical case on the open side. And a plurality of notch grooves that are fixed to the housing and are engaged with the locking protrusions are formed on the inner peripheral surface of the housing so that the locking protrusions can come into contact with the open-side end of the outer peripheral tubular portion. And a fixed ring having a thrust receiving plate, a plurality of cutout grooves formed on an outer peripheral surface of the inner peripheral cylindrical portion of the cylindrical case so as to be movable in the axial direction, and engaging with the locking protrusions. And a spring for pressing the fixed ring against the rotary ring.

[Action]

The locking projection provided on the cylindrical case engages both the notch groove on the inner peripheral surface of the thrust receiving plate and the notch groove on the outer peripheral surface of the fixed ring to prevent the cylindrical case from rotating with respect to the housing. It also has a function to prevent the fixed ring from rotating with respect to the housing. The thrust receiving plate includes thrust receiving means for preventing the cylindrical case from axially moving in the direction of coming out of the housing to the rotary ring side by the pressure of the fluid to be sealed existing on the inner peripheral side of the housing, and the inner peripheral surface thereof. The engagement of the notch groove of the surface and the locking projection also serves as a means for preventing rotation of the cylindrical case and the fixed ring with respect to the housing.

〔Example〕

Hereinafter, an outside mechanical seal according to the present invention will be described with reference to an embodiment shown in FIGS. 1 and 2.

In FIG. 1, reference numeral 20 is a housing of the device, 22 is a rotary shaft inserted through the inner periphery of the shaft hole of the housing 20, and 35 is a rotating body outside the housing 20 and rotated by the rotary shaft 22. . The outside mechanical seal of this embodiment includes a seal sliding surface S that is a fixed ring provided on the housing 20 side and a mating ring 34 that is a rotating ring provided on the rotating body 35 side. To prevent the fluid A to be sealed on the inner circumference of the housing 20 from leaking from the axial clearance between the housing 20 and the rotary shaft 22.

That is, the inner peripheral surface 21 of the end portion of the housing 20 has an inner diameter that is not in contact with the outer peripheral surface of the rotating shaft 22, and the mating ring 34
On the other hand, in other words, a cylindrical case 24 having a substantially U-shaped cross section, which is open toward the outside of the housing 20, is tightly fitted via an O-ring 23. That is, this cylindrical case 24 is
24a, an inner peripheral tubular portion 24b, and a rear surface portion 24c on the side opposite to the open end portion. As shown in the perspective view of FIG. 2, the outer peripheral tubular portion 24a has an open end. A plurality of locking protrusions 25 are provided at equal intervals in the circumferential direction, and each locking protrusion 25 is bent toward the inner diameter side from the upper axial direction portion 25a on the base side and the upper axial direction portion 25a. It is composed of a lower axial direction portion 25b formed via a step portion.

The seal ring 27 is arranged in the cylindrical case 24, and is supported by the inner peripheral cylindrical portion 24b of the cylindrical case 24 via an O-ring 26 so as to be axially movable. On the outer peripheral surface of the seal ring 27, a plurality of notched grooves 28 extending in the axial direction are formed at equal intervals in the circumferential direction, and each notched groove 28 is formed with a lower axial portion 25b of each locking projection 25. Each is engaged so as to be slidable in the axial direction. A plurality of recesses 29 are formed at equal intervals in the circumferential direction on the surface of the seal ring 27 opposite to the sealing sliding surface S. One end of each recess 29 is the rear surface 24c of the cylindrical case 24. A spring that abuts against the seal ring 27 and presses the seal ring 27 toward the mating ring 34 in the axial direction.
30 are arranged.

A stopper 31 is arranged between the O-ring 26 on the inner circumference of the seal ring 27 and the rear surface portion 24c of the cylindrical case 24. The stopper 31 reaches the inner circumference of the sealing sliding surface S via the gap G between the rotary shaft 22 and the cylindrical case 24, and the fluid A to be sealed is reached.
The pressure prevents the O-ring 26 from deviating from the inner peripheral surface of the seal ring 27 toward the back surface portion 24c and impairing the sealing performance. Also, like this, the O-ring 26
Is restricted by the movement of the
The pressure of the fluid A to be sealed is applied as a load for pressing the seal ring 27 to the mating ring 34 side together with the urging force of the spring 30.

Further, a thrust receiving plate 32 having an inner diameter smaller than the inner peripheral surface 21 of the end of the housing 20 is fixed to the end of the housing 20 by a bolt (not shown).
When the open side of the outer peripheral tubular portion 24a of the cylindrical case 24, that is, the end on the locking projection 25 side abuts on the inner diameter portion of the thrust receiving plate 32, the cylindrical case 24 becomes a housing.
It is prevented from moving in the direction of coming out of the housing 20 under the pressure of the fluid A to be sealed 20.

On the other hand, the rotating mating ring 34, which is in sliding contact with the seal ring 27, is tightly fitted to the annular recess of the inner diameter of the rotating body 35 fixed to the rotating shaft 22 via the O-ring 37, and is provided on the outer peripheral portion thereof. The formed notch engages with the knock pin 36 implanted in the rotating body 35, whereby the rotating shaft 22 and the rotating body are
It is designed to rotate together with the 35.

According to this embodiment, the locking projection 25 of the cylindrical case 24 engages with the notch groove 33 of the thrust receiving plate 32 to form a rotation preventing means for the cylindrical case 24 with respect to the housing 20, and also to prevent the seal ring 27 from rotating. By engaging with the notch groove 28 on the outer peripheral surface, the seal ring 27 is prevented from rotating with respect to the housing 20. Further, the thrust receiving plate 32 is a thrust receiving means for preventing the cylindrical case 24 from coming out of the housing 20 to the mating ring 34 side by the pressure of the fluid A to be sealed, and the notch groove 33 on the inner peripheral surface thereof is a cylinder. By engaging with the locking projections 25 of the case 24, it also serves as a rotation preventing means for the cylindrical case 24 with respect to the housing 20 and a rotation preventing means for the seal ring 27.

Therefore, since it is not necessary to implant a knock pin or the like as the rotation stopping means in the cylindrical case 24, a press-formed product of a thin metal plate can be obtained, and the structure is simplified, which facilitates manufacturing. The cost can be reduced.

[Effect of device]

As is apparent from the above description, according to the outside mechanical seal of the present invention, the notch groove formed in the inner peripheral surface of the thrust receiving plate, the locking protrusion protruding from the cylindrical case, and the fixing ring. Since the notch grooves formed on the outer peripheral surface of the cylinder engage with each other in an interconnected state to prevent the cylindrical case and the fixed ring from rotating with respect to the housing, the bolt fastening portion for preventing the cylindrical case itself from rotating. There is no need to install a knock pin or a knock pin, so the structure is simple.
Compact size, easy assembly and disassembly, and cost reduction.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of an outside mechanical seal according to the present invention, FIG. 2 is a perspective view of a cylindrical case in this embodiment, and FIG. 3 is a conventional outside mechanical seal. FIG. 20 …… housing, 22 …… rotating shaft, 23,26,37 …… O-ring 24 …… cylindrical case, 25 …… locking protrusion, 27 …… seal ring (fixed ring) 28,33 …… notch groove, 32 …… Thrust receiving plate 34 …… Mating ring (rotating ring)

Claims (1)

[Scope of utility model registration request] 1. A rotating ring, which is arranged around an axis of a rotary shaft inserted through an inner circumference of a housing and is tightly fitted to a rotary body integrated with the rotary shaft, and a rotary ring which is tightly fitted to an inner circumferential surface of an end portion of the housing. A cylindrical case having a substantially U-shaped cross-section that is open toward the ring side, a plurality of locking projections that project from the open-side end of the outer peripheral tubular portion of the cylindrical case, and the opening of the outer peripheral tubular portion. A thrust receiving plate fixed to the housing in a state capable of abutting the end portion on the side and having a plurality of cutout grooves formed on the inner peripheral surface thereof to be engaged with the locking projections; and an inner peripheral cylinder of the cylindrical case. A fixed ring in which a plurality of cutout grooves are formed on the outer peripheral surface of which is tightly fitted in a state of being axially movable, and a spring which presses the fixed ring against the rotary ring. An outside mechanical seal that is characterized by: