JPH0722531Y2 - Gland packing shaft seal structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a shaft packing structure of a gland packing used for shaft sealing of various devices such as a stirrer, a blower, and a mixer.

(B) Prior Art Conventionally, in the shaft sealing structure of the gland packing described above, for example, as shown in FIG. 5, a tightening nut 10 screwed to a bolt shaft 9 of the shaft sealing portion 1 is tightened, and a shaft hole 2 is formed. Via the packing retainer 8 fitted to the atmosphere side, the gland packings 4 ... Press-fitted into the gap between the inner peripheral surface of the shaft hole 2 of the shaft sealing portion 1 and the outer peripheral surface of the rotary shaft 3 are added in the axial direction. There is a shaft sealing structure in which the inner peripheral surface of each of the gland packings is brought into close contact with the outer peripheral surface of the rotating shaft 3 in the radial direction by pressing to seal the inner peripheral surface.

In the above-mentioned conventional example, the same components as those in the first embodiment described later are designated by the same reference numerals, and detailed description thereof will be omitted.

(C) Problems to be solved by the invention In the shaft sealing structure described above, the tightening force of the tightening nut 10 is less likely to be applied to the gland packing 4 on the inner side of the shaft sealing, that is, the liquid sealing side, and the shaft of the shaft sealing part 1 is less likely to be applied. The relationship between the axial contact surface pressure P, the radial contact surface pressure P ′, and the tightening force P _G generated in each gland packing 4 ... Inside the hole 2 is P _G >P> P ′. .

As shown in FIG. 4, the distribution of the contact surface pressure P'applied to each gland packing 4 in the radial direction is such that the contact surface pressure on the sealing liquid side is very small and the contact surface pressure P'on the atmosphere side is very small. Since it is higher than that on the liquid-sealing side, the gland packing 4 on the liquid-sealing side cannot obtain a sufficient contact surface pressure for sealing, and there is a tendency that the gland packing 4 on the atmosphere side mainly seals.

As a result, the gland packing 4 on the atmosphere side having a high radial contact surface pressure P ′ is abnormally worn and the sealing function is rapidly deteriorated, and the sealing function of the gland packings 4 on the liquid sealing side and the atmosphere side is deteriorated. The fluid flowing on the sealing liquid side leaks,
If the foreign matter such as abrasion powder generated on the sliding surface between the rotating shaft 3 and the gland packing 4 is mixed in the fluid, the tightening nut 10
There is a problem that it is necessary to frequently perform maintenance such as re-tightening or replacing the gland packing 4 on the atmosphere side where the wear is remarkable.

Further, in order to prevent the above-mentioned deterioration of the sealing function, if the tightening nut 10 is strongly tightened to increase the radial contact surface pressure P ′ applied to the gland packing 4 on the liquid sealing side,
There is also a problem in that the gland packing 4 on the atmosphere side is unnecessarily applied with the other-field contact surface pressure, which shortens the wear rate and the life.

The purpose of this invention is to reliably prevent liquid leakage and foreign matter from entering the fluid, and to improve the sealing function. Especially, in the shaft sealing structure using the gland packing, the tightening pressure is reduced. In addition, it is to provide a shaft seal structure of a gland packing capable of improving the sealing property of the gland packing located at the innermost part (sealing side) where sufficient contact pressure with the shaft cannot be obtained.

(D) Means for Solving Problems The invention according to claim 1 of the present invention seals a gap between the inner peripheral surface of the shaft hole of the shaft sealing portion and the outer peripheral surface of the rotary shaft inserted into the shaft hole. A gland packing shaft sealing structure, in which a shaft sleeve is fitted and fixed to the outer peripheral surface of the rotating shaft, and a small area is provided on the outer peripheral surface of the shaft sleeve facing the liquid sealing side. A sealing surface is formed, the gland packing is axially pressed against the sealing surface, the inner peripheral surface of the gland packing is brought into close contact with the outer peripheral surface of the shaft sleeve, and the sealing liquid side end surface of the gland packing is It is characterized by a gland packing shaft sealing structure that is in close contact with the sealing surface.

According to a second aspect of the present invention, there is provided a gland packing shaft sealing structure for sealing a gap between an inner peripheral surface of a shaft hole of a shaft sealing portion and an outer peripheral surface of a rotary shaft inserted in the shaft hole. A shaft sleeve is fitted and fixed on the outer peripheral surface of the rotating shaft, and a small-area sealing surface is formed on the outer peripheral surface of the shaft sleeve on the liquid sealing side facing the liquid sealing side end surface of the gland packing. The gland packing in an axial direction by pressing the gland packing in an axial direction to bring the inner peripheral surface of the gland packing into close contact with the outer peripheral surface of the shaft sleeve, and to seal the liquid sealing side end surface of the packing ring provided on the liquid sealing side end surface of the gland packing. It is characterized by a shaft seal structure of gland packing that closely adheres to the surface.

(E) Action According to the present invention, by pressing the gland packing in the axial direction to tighten the gland packing, the inner peripheral surface of the entire gland packing is brought into close contact with the outer peripheral surface of the rotating shaft in an airtight state, and at the same time, The sealing surface formed on the outer peripheral surface of the sealing liquid is in close contact with the sealing liquid side end surface of the gland packing in the shaft sealing inner part, and the sealing liquid side end surface of the shaft sealing inner part and the rotating shaft sealing surface. A pressing force acts in a direction in which the and are in surface contact with each other, and a contact surface pressure equal to or greater than the radial contact surface pressure is generated, and the gland packing in the shaft sealing inner portion seals simultaneously in the radial direction and the axial direction.

Moreover, the centrifugal force due to the rotation of the rotating shaft acts between the sealing liquid side end surface of the gland packing in the inner portion of the shaft sealing and the gas or powder that tries to enter the contact surface, A force such as a mist that pushes the fluid back to the sealing liquid side acts, and the synergistic action of the surface contact and the centrifugal force reliably prevents the fluid from leaking and foreign matter from entering the fluid.

In short, since the seal part having a small area in the axial direction on the sealing liquid side is brought into contact with the innermost gland packing, the sealing surface pressure can be maintained high, and the shaft acting on the innermost gland packing can be maintained. The contact pressure in the radial direction, which is the conversion of the tightening pressure in the direction, can be maintained at a high level, and since the seal part is in contact with the sealing side of the innermost gland packing, the sliding of the shaft and gland packing It is possible to prevent the abrasion powder and the like generated by the above from being mixed in the sealing liquid.

(F) Effect of the invention As described above, since the pressing force is applied in the direction in which the sealing liquid-side end surface of the gland packing in the shaft sealing inner part and the sealing surface are in surface contact with each other, the contact pressure is equal to the radial contact surface pressure. The above contact surface pressure can be obtained, and the contact surface pressure obtained between the atmosphere side and the liquid sealing side can be set to a more approximate value to stabilize the sealing function. That is, it is possible to improve the sealing property of the gland packing located at the innermost portion (sealing liquid side).

Moreover, since the centrifugal force due to the rotation of the rotary shaft acts between the sealing liquid side end surface of the gland packing in the inner part of the shaft seal and the sealing surface of the rotary shaft, mutual surface contact and centrifugal force cause a synergistic effect. It is possible to reliably prevent the leakage of the liquid and the inclusion of foreign matter such as abrasion powder in the fluid, and improve the sealing function of the gland packing in the inner part of the shaft seal.

(G) Embodiment (First Embodiment) An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows the shaft sealing structure of the gland packing, and in FIG. 1, it is formed by the inner peripheral surface of the shaft hole 2 formed in the shaft sealing portion 1 and the outer peripheral surface of the rotary shaft 3 inserted into the shaft hole 2. A plurality of gland packings 4 formed of, for example, PTFE-impregnated carbonized fiber are press-fitted into the space.

Each of the above-mentioned gland packings 4 ... Is fitted on the peripheral surface of the shaft sleeve 5 which is fitted and fixed on the outer peripheral surface of the rotary shaft 3, and the annular step portion 6 formed on the peripheral surface of the shaft sleeve 5 on the liquid sealing side. Seal surface
6a and the end surface of the neck bush 7 fitted and fixed to the liquid seal side inner peripheral surface of the shaft hole 2 are brought into contact with the liquid seal side end surface 4a of the gland packing 4 arranged in the shaft seal inner part to form a shaft seal. The positions of the gland packings 4 are regulated on the peripheral surface of the portion 1 facing the inner peripheral surface of the shaft hole 2.

The minimum inner diameter of the gland packing 4 is used as a reference so that the sealing surface 6a of the annular stepped portion 6 comes into contact with the half circumferential surface of the liquid-side end surface 4a of the gland packing 4 in the shaft sealing inner part. The annular step 6 is formed by the dimensional difference between the maximum outer diameter dimension and the minimum inner diameter dimension of the gland packing 4, that is, the x dimension in which the y dimension is halved.

On the other hand, the packing presser 8 is fitted to the atmosphere side of the shaft hole 2 described above, and the end surface of the packing presser 8 on the liquid sealing side is brought into contact with the end surface of the gland packing 4 on the atmosphere side, and the outer peripheral edge of the packing presser 8 is The bolt shaft 9 screwed and fixed to the outer surface of the shaft sealing portion 1 is made slidable in the insertion hole 8a opened in the, and the tightening nut 10 screwed into the tip end of the bolt shaft 9 on the insertion side is tightened in the tightening direction. By rotating, the gland packings 4 ... Are sandwiched and fixed between the annular step portion 6 and the neck bush 7 formed on the rotary shaft 3 and the packing retainer 8.

The illustrated embodiment is constructed as described above, and the operation will be described below.

As shown in FIG. 1, a tightening nut 10 screwed onto the bolt shaft 9 of the shaft sealing portion 1 is tightened at 10 kg / cm ² , and each gland packing 4 ... through the packing retainer 8 ... Axial direction (arrow direction). By compressing the gland packing 4, each gland packing 4 ... is compressed in the axial direction, and material elasticity acts in the axial direction and the radial direction.
The inner peripheral surface of each gland packing 4 ... is closely adhered to the outer peripheral surface of the rotating shaft 3 in the radial direction, and as shown in FIG.
In the gland packing 4 at the inner part of the shaft seal located when x = a, a radial contact surface pressure P'l _{= a} = 6.3 kg / cm ² is obtained.

At the same time, the sealing surface 6a of the annular stepped portion 6 formed on the shaft sleeve 5 on the rotary shaft 3 is in close contact with the liquid-side end surface 4a of the gland packing 4 in the shaft sealing inner part, and the shaft sealing located at the distance a. In the inner gland packing 4, the contact surface pressure P _{l = a} = 9kg / cm
You get ² .

At this time, the sealing liquid side end surface of the gland packing 4 in the inner part of the shaft seal
4a and the sealing surface 6a formed on the rotary shaft 3 are in surface contact with each other, and a pressing force (tightening force) acts in the axial direction, so that the liquid sealing end surface 4a of the gland packing 4 in the shaft sealing depth and the sealing surface 6a A contact surface pressure P _{1 = a} = 9 kg / cm ² is generated on the shaft, and a radial contact surface pressure P ′ acting on the gland packing 4 and the rotary shaft 3 in the inner portion of the shaft seal is provided.
Contact surface pressures higher than _{l = a} ² = 6.3 kg / cm ² are obtained.

In this way, the sealing liquid side end surface of the gland packing 4 at the inner part of the shaft seal
Since the pressing force (tightening force) is applied in the direction in which the 4a and the seal surface 6a formed on the rotary shaft 3 come into surface contact, a contact surface pressure P equal to or greater than the radial contact surface pressure P'is obtained. The surface pressure obtained in each gland packing 4 between the atmosphere side and the liquid sealing side can be set to a more approximate value to stabilize the sealing function.

Moreover, the sealing liquid side end surface 4a of the gland packing 4 in the inner part of the shaft seal
The centrifugal force due to the rotation of the rotary shaft 3 acts on the seal surface 6a formed on the rotary shaft 3 and the surface contact between the seal surface 6a and the centrifugal force exerts a synergistic effect on the seal liquid side end surface 4a and the seal surface 6a. A force that pushes back the fluid such as gas, powder, mist, etc., which enters into the space toward the sealing liquid side, and at the same time, wear powder, etc. generated on the sliding surface between each gland packing 4 ... It is possible to reliably prevent foreign matter from mixing into the fluid, and improve the sealing function of the gland packing 4 in the inner portion of the shaft seal.

Further, the sealing liquid side end surface 4a of the gland packing 4 in the shaft seal inner part
On the other hand, the contact area of the seal surface 6a formed on the rotary shaft 3 is 1/2, that is, the contact area is 2/3 or less of the clearance, so that the rotary resistance of the rotary shaft 3 does not become smooth. You can get a nice rotation.

In short, since the seal surface 6a having a small area in the sealing liquid axial direction is brought into contact with the innermost gland packing 4, the seal surface pressure can be kept high, and the innermost gland packing 4 can be maintained. The contact pressure in the radial direction, in which the acting tightening pressure in the axial direction is converted, can be kept high, and further, since the seal surface 6a is in contact with the liquid packing side of the innermost gland packing 4, the shaft 3 And gland packing 4
It is possible to prevent the abrasion powder and the like generated by the sliding of the item from being mixed in the sealing liquid.

(Second Embodiment) The shaft sealing structure of the second embodiment shown in FIG. 2 is a structure that absorbs a decrease in the contact surface pressure P due to movement in the axial direction when the rotary shaft 3 rotates.

As shown in the figure, the sliding ring 11 fitted on the rotary shaft 3
And the sliding ring 12 fitted on the inner peripheral surface of the shaft hole 2 of the shaft sealing portion 1.
And are provided so as to be slidable in the axial direction.
Is urged toward the atmosphere side by the respective springs 13 and 13 'interposed on the sealing liquid side, and the sealing surface 11a of the sliding ring 11 is brought into close contact with the sealing liquid side end surface 4a of the gland packing 4 in the shaft sealing depth, The packing 14 is biased toward the sealing liquid side by the spring 14 wound between the bolt shaft 9 screwed and fixed to the outer surface of the shaft sealing portion 1 and the tightening nut 10, and the gland packing 4 in the inner portion of the shaft sealing 4 is pressed. The end surface 4a on the liquid sealing side and the sealing surface 11a of the sliding ring 11 are constantly maintained at a predetermined contact surface pressure P.

According to this structure, the same effects as those of the above-described first embodiment can be obtained, and the sliding rings 11 and 12 and the gland packings 4 can be moved by following the movement of the rotating shaft 3 in the axial direction. ... and the packing retainer 8 move while in surface contact,
The contact surface pressure P between the liquid-side end surface 4a of the gland packing 4 and the seal surface 11a of the sliding ring 11 in the shaft seal inner part is prevented from decreasing.

(Third Embodiment) In the shaft sealing structure of the third embodiment shown in FIG. 3, for example, a hard packing ring 15 made of a carbon-filled PTFE resin is arranged in the shaft sealing inner part, and, for example, PTFE impregnated carbonization. The sealing surface 6a formed on the rotary shaft 3 is pressed against the sealing liquid side end surface 15a of the packing ring 15 through a plurality of gland packings 4 formed of fibers.

According to this structure, the same effect as that of the first embodiment described above can be obtained, and by adjusting the width of the liquid sealing side end surface 15a of the packing ring 15, for example, the tightening nut 10 can be 2.
If tightened at 5 kg / cm ^2, it is possible to set the contact pressure P of the sealing surface 6a formed on the rotating shaft 3 and the sealing liquid side end face 15a of the packing ring 15 to 6 kg / cm ^2, A large contact surface pressure P can be obtained with a small tightening force as compared with the first embodiment.

In each of the second to third embodiments described above, the same components as those in the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted.

[Brief description of drawings]

The drawings show one embodiment of the present invention, FIG. 1 is a vertical sectional side view showing a shaft sealing structure of a gland packing of the first embodiment, and FIG. 2 is a vertical sectional view showing a shaft sealing structure of a gland packing of the second embodiment. Side view, FIG. 3 is a vertical cross-sectional side view showing the shaft sealing structure of the gland packing of the third embodiment, FIG. 4 is an explanatory view of the distribution of the contact surface pressure in the radial direction and the axial direction, and FIG. It is a vertical side view which shows the shaft sealing structure of packing. 1 ... Shaft sealing part, 2 ... Shaft hole 3 ... Rotating shaft, 4 ... Gland packing 5 ... Sleeve sleeve, 4a, 15a ... End surface 6a, 11a ... Sealing surface 15 ... Packing ring

Claims (2)

[Scope of utility model registration request] 1. A gland packing shaft seal for sealing a gap between an inner peripheral surface of a shaft hole (2) of a shaft sealing portion (1) and an outer peripheral surface of a rotary shaft (3) inserted in the shaft hole (2). A shaft sleeve (5) is fitted and fixed to the outer peripheral surface of the rotary shaft (3), and the shaft sleeve (5) faces the liquid-side end surface (4a) of the gland packing (4). A sealing surface having a small area is formed on the outer peripheral surface of the sealing liquid side, the gland packing (4) is axially pressed against the sealing surface (6a), and the inner peripheral surface of the gland packing (4) is attached to the shaft. A shaft seal structure for a gland packing, which is in close contact with the outer peripheral surface of the sleeve (5) and in which the liquid sealing side end surface (4a) of the gland packing (4) is in close contact with the sealing surface (6a). 2. A gland packing shaft seal for sealing a gap between an inner peripheral surface of a shaft hole (2) of a shaft sealing portion (1) and an outer peripheral surface of a rotary shaft (3) inserted through the shaft hole (2). The shaft sleeve (5) is structured such that a shaft sleeve (5) is fitted and fixed to the outer peripheral surface of the rotating shaft (3), and the shaft sleeve (5) faces the liquid-side end surface (4a) of the gland packing (4). A small area sealing surface (6a) is formed on the outer peripheral surface of the sealing liquid side, and the gland packing (4) is axially pressed against the sealing surface (6a) to form an inner peripheral surface of the gland packing (4). Is closely attached to the outer peripheral surface of the shaft sleeve (5), and the liquid sealing end surface (15a) of the packing ring (15) provided on the liquid sealing end surface (4a) of the gland packing (4) is connected to the sealing surface ( Shaft seal structure of gland packing that closely adheres to 6a).