JPS6023675A - Mechanical seal for shaft shift - Google Patents

Abstract

PURPOSE:To decrease a load and reduce abrasion by preventing a thrust sleeve from being applied with a thrust force due to a liquid pressure and applying only a load via an elastic means to sealed sliding surfaces. CONSTITUTION:A proper face pressure is invariably applied to sealed sliding surfaces 53, 57 by the pressing force of a coil spring 67 regardless of shaft shift directions of a rotary shaft 3. Radial notches are provided on the sealed sliding surface 57 on the left side to keep a chamber A and a chamber B at the same pressure, and the outer diameter d1 and the inner diameter d2 of a thrust sleeve 54 are formed equal so that no thrust force due to the liquid pressure is applied. Therefore, the load to the sealed sliding surfaces 53, 57 can be made small and the seal life can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanical seal used as a shaft sealing device, and more specifically, the present invention relates to a mechanical seal used as a shaft sealing device, and more specifically, the present invention relates to a mechanical seal that is used as a shaft sealing device, and more specifically, a mechanical seal that moves in the axial direction of a rotating shaft of each Yuzu rotating device with respect to a main body of the device that supports the rotating shaft. The present invention relates to a mechanical seal for shaft movement that seals the gap between the main body and the rotating shaft in such cases.

A mechanical seal as shown in FIG. 1 has been known as an example of this type of mechanical seal. In the figure (1
) shows a part of the main body of a rotating device, in which a rotating shaft (3) with a step (4×5) is inserted into a shaft hole (2) drilled in the device main body (1).

A cylindrical sleeve (6) is fitted onto the rotating shaft (3) in an airtight manner. (8) is a key fixed to the rotating shaft (3) in a buried state, and is engaged with a key length (7) formed on the inner peripheral surface of the sleeve (6).
) is made to follow the rotating shaft (3). A flange (9) is fixed to the front surface of the device main body (1). A flange (10) facing inward is formed at the front end of the flange (9), and a seal cover (11) is fitted inside the flange (10).

This seal cover (11) has an O ring (1
3) through which the 70-tingseat (12) is fitted. A step (2a) is formed at the opening of the shaft hole (2) of the device body (1), and another seal cover (14) is fitted into the step (2a). A floating retainer (15) is fitted on the substantially inner diameter side of this seal cover (14) via an O-ring (16), and a second 74-tingseat (17) is fitted on the front end surface of the floating retainer (15). ing. (18) is the 70-ting sheet (12)
) and a 70-ring retainer (15), the inner circumferential surface of which is in contact with the sleeve (6) and a hexagonal socket hole (19) that penetrates in the radial direction. It is equipped with This Pol) (19
) A guide shoe (20) is screwed onto the tip.

The guide shoe (20) is engaged with a guide groove (21) formed on the outer circumferential surface of the sleeve (6), and the mating retainer (18) is connected to the rotating shaft (3) through the sleeve (6). It will follow the rotation of.

The axial length tl) of the guide shoe (20) is shorter than the length t2) of the guide groove (21). A mating ring (22) is fitted onto the rear end surface of the mating retainer (18).

(23) (24) are dowel pins for stopping the rotation, (25)
is a spacer, (26827×28) and (29) are 0 rings.

The conventional mechanical seal having the above structure has the above-mentioned 74-
mating seat (12) and mating retainer (18)
) and a mating ring (22) fitted to the mating retainer (18) and a second 7 μm
sealing surface (17) and sliding surface (3).
0031), even if the rotating shaft (3) and the sleeve (6) fitted thereon move in the axial direction with respect to the main body (1), the maintaining retainer (18)
is sandwiched between two 74-ring seats (12) and (17) to prevent its movement in the axial direction, and the first sleeve (6) maintains airtightness against the inner peripheral surface of this mating retainer (18). It is configured to slide. Therefore, compared to normal mechanical seals (those not configured for shaft movement), this mechanical seal changes its travel length as it does when the shaft moves, and the spring (tightly pierced) applies blood pressure to the sliding surface. The mechanical seal will not be damaged due to changes in the load (applied to the mechanical seal) due to insufficient or excessive surface pressure on the seal sliding surface, but the 18) is not hydraulically balanced, the thrust load due to hydraulic pressure may always be applied to the sealing sliding surface (30X31), resulting in excessive surface pressure. ) was causing damage.

The present invention has been made in view of the above points, and a 70-teating sheet and a thrust receiver, which are fixed to the main body of the device, are arranged opposite to each other, and between these two, the driven rotation with respect to the rotating shaft is prevented. However, a light seal ring and a thrust sleeve are arranged so as to be movable in the axial direction, and an elastic means such as a coil spring is interposed between the two, and a thrust force due to hydraulic pressure is not applied to the thrust sleeve. A step is provided to make the outer diameter and the inner diameter equal, and the 70
- rc so that only the load by the elastic means is applied to the sealing sliding surface formed by the opposing surfaces of the sealing seat and the seal ring, the thrust receiver and the thrust sleeve;
It is an object of the present invention to provide a mechanical seal for shaft movement having the following structure. Due to the above-mentioned configuration, the mechanical seal has excellent durability because no hydraulic pressure acts on the sealing sliding surface trap, and the load is small and wear can be kept to a minimum. To explain, in FIG. 2, a case (41) is fitted around the opening of the shaft hole (2) of the device body (1), and the case (41)
A flange (42) is attached to the front surface of the flange (42) by screwing with a hexagonal bolt (43). A floating seam is attached to the inner circumference of this flange (42) via an O ring (46).
(45) is fitted. (44) is the flange (
42) is a dowel pin that protrudes in the radial direction on the inner peripheral surface of the 70-ting seat (45), and is engaged with a notch formed in the front end of the 70-ting seat (45).
45) times) Make a stop. A thrust receiver (47) is provided on the inner periphery of the rear end of the case (41) via an O-ring (48).
is fitted. Reference numeral (49) denotes a knock pin that protrudes radially inward from the inner peripheral surface of the rear end of the case (41), and is engaged with a notch formed in the rear end of the thrust receiver (47). It prevents the receiver (47) from turning. A seal ring (50) and a thrust sleeve (54) are arranged between the floating sea (45) and the thrust receiver (47).

This seal ring (50) is a sliding member (51) with a rectangular cross section.
and the holding member (52), and a first sealed sliding surface (53) is formed by contact between the front end surface of the sliding member (51) and the rear end surface of the 70-tingseat (45). . The other thrust sleeve (54) is connected to the sliding member (55) and the holding member (56), and the rear end surface of the sliding member (55) and the front end surface of the thrust receiver (47) come into contact with each other, causing flooding 2.
A sealing sliding surface (57) is formed. A large number of radial notches are provided on the front end surface of this thrust receiver (47),
The MU sliding surface (57) serves to make chambers A and B separated by the same pressure. The thrust sleeve (54)
The front end of the holding member (56) has an outer circumferential surface in contact with the inner circumferential surface of the holding member (52) of the seal ring (50), and an inner circumferential surface in contact with the curved surface of the rotating shaft (3). A small-diameter cylindrical portion (58) is integrally formed, and the small-diameter cylindrical portion (58) and the holding member (5) on the seal ring (50) side are integrally formed.
2) is interposed with an O-ring (59) for airtightness. (60) is a collar fixed to the circumferential surface of the rotating shaft (3) by a set screw (61).

The collar (60) has a knock bottle (
A locking hole (62) is provided in a protruding manner, and the tip of the knock pin (62) is placed in the small diameter cylindrical portion (58) in the axial direction.
63). In addition, this small diameter cylindrical part (58)
A drive pin (64) is provided at the front end of the drive pin (64) to protrude axially forward. This drive pin (64) is connected to the sliding member (51) of the seal ring (50) and the holding member (52).
It is engaged with locking grooves (65) and (66) formed on the inner circumferential surface of. (67) is a holding member (52) of the seal ring (50) and a holding member (52) of the thrust sleeve (54).
6) (Small diameter cylindrical part (58)) with a coil spring loaded between them.

A plurality of coil springs (67) are arranged at equal intervals in the circumferential direction. (68X69) is the above force, F - (6
This is an O-ring for airtightness that is fitted on the inner and outer peripheries of the 0).

In the mechanical cool with the above configuration, the outer diameter (dl
) immediately behind said small diameter front section (58) and said collar (6).
0), and the minimum inner diameter of the thrust receiver (47) (d is the force? - the maximum outer diameter of (60) (larger than d). is formed.

Next, the operation of the mechanical seal will be explained.

When the rotating shaft (3) rotates, the collar (60) is directly fitted onto the rotating shaft (3), and the thrust sleeve (54) is connected to the collar (613) via a dowel pin (62).
), the drive pin (64) is attached to the thrust sleeve (54).
) The members of the seal link (50) connected through the seal link (50) are driven to rotate, and the liquid to be sealed is contained by the action of the sealing sliding surface (53×57).

When the rotating shaft (3) moves in the axial direction relative to the device body (1), for example, when the rotating shaft (3) moves to the right in FIG. Applied force 9-
(60) follows this, but the seal ring (50) and the stripe (54) are floating sea) (
A dowel pin (62), which is sandwiched between the thrust receiver (45) and the thrust receiver (47) and protrudes at a force /' ) is loosely fitted in the axial direction into the locking hole (63) provided in the rotary shaft (3), so it does not follow the movement of the rotating shaft (3). That is, in this case, on the diagram (ts,
(As the interval indicated by to becomes narrower, the color (60
) and the holding member (56) (portion (70)) of the thrust sleeve (54), and the contact surface between the small diameter cylindrical portion (58) of the holding member (56) and the rotation @ (3) are in sliding contact. .

Similarly, when the rotating shaft (3) moves to the left in the figure, the interval (t5) becomes narrower. Therefore, the sealing sliding surface (53) (
57), regardless of the axial movement of the rotation shaft (3), appropriate surface pressure is always applied by the coil spring (67), and the left sealing sliding movement (57) A radial notch is provided to maintain the same pressure in chambers A and B, and also to maintain the same pressure.
The outer diameter (dl) and the inner diameter (d2) of the are formed to be equal and are configured not to receive thrust force due to hydraulic pressure, so the load on the sealing sliding surfaces (53) and (57) is kept small (the above-mentioned (only the coil spring (67)) can reduce wear and prolong the life of the seal.

Also, the color (60) K is an O-ring (68 to 69)
Since the dowel pin (62) and coil spring (67) do not come into contact with the liquid, the dowel pin (62) and coil spring (67) have excellent rigidity and leakage properties. In addition, the minimum inner diameter (d3) of the thrust receiver (47) is set to the rotation axis (3).
By forming the seal with a diameter larger than the maximum outer diameter (d4) of the collar (60) that is directly fitted to the case (4
1) and a flange (42), which is a so-called cartridge (unit), assembled outside the machine,
It can be assembled to the device main body (1) at once. Further, the small diameter front portion (54) of the thrust sleeve (54)
8) By applying hard chrome plating or the like to the inner circumferential surface, the sliding resistance with the rotating shaft (3) can be suppressed to a low level, and the responsiveness to shaft movement can be improved.

As explained above, the mechanical seal for shaft movement of the present invention eliminates the effect of hydraulic pressure on the sliding surface, which was a drawback of conventional products, and can maintain stable sealing performance over a long period of time. .

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a half-cut sectional view of a conventional mechanical seal for moving a shaft, and FIG. 2 is a half-cut sectional view of a mechanical seal for moving a shaft according to the present invention. (1) Equipment body (2) Shaft hole (3) Rotating shaft (41) Case (42) N2-inch (43) Hexagonal bolt (440)
49X62) Dowel pin (45) 70-ting sheet

Claims (1)

[Claims] In a mechanical seal attached to a rotating device in which a rotating shaft (3) mounted on the device body (1) moves relative to the device body (1) in the axial direction, the device body (1)
A floating seam (45) and a thrust receiver (47) are arranged opposite each other, and a floating seat (45) and a thrust receiver (47) are fixed to the rotating shaft (3). Seal ring that rotates as a result (50
) and a thrust sleeve (54) are arranged so as to be movable in the axial direction with respect to the rotating shaft (3), and this seal ring (5
An elastic means such as a coil spring (67) is interposed between the thrust sleeve (54) and the thrust sleeve (54), and the outer diameter (dl) and inner diameter are A mechanical seal for shaft movement whose % characteristic is that a step is provided to equalize (d+).