JPH0293169A - Packing for sealing rotary body - Google Patents

Abstract

PURPOSE:To improve lubricity and prolong the service life by forming an annular projection which is continuous in the peripheral direction onto the circumference on the contact side with the rotary body of a packing body made of elastic material, in inclination for a revolution axis line. CONSTITUTION:In a packing 20 for sealing a rotary body, at least one stripe of annular projection 24 which continues in the peripheral direction is formed on the peripheral surface on the slide contact side with a rotary body 6 of a packing body 22 made of elastic material, and at least a part of a sealing line 26 is tilted in an acute angle or an arbitrary obtuse angle theta for a revolution axis line 28. Therefore, the sliding speed V in the direction perpendicular to the sealing line 26, i.e., in the leak direction is set in the relation V=Vrcostheta, for the sliding speed Vr of the rotary body,and the sealing gap (h) is set in the relation (h)=mu.Vcostheta/p, and when the pressure P of the sealing fluid 34 increases, the sealing gap (h) reduces, and lubrication for the sealing surface becomes difficult, but since the sliding speed V in the leak direction can be set large, the gap (h) can be increased, and the lubrication for the sealing surface is improved. Therefore, the sealing life can be prolonged considerably.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a rotating body sealing packing which is arranged between a member that rotates relative to each other, such as a rotating shaft and a casing, and which prevents fluid leakage.

Technical Background of the Invention and Problems There are mechanical elements such as oil seals, O-rings, and A packing for a rotating shaft is known.

For example, an oil seal 2 as illustrated in FIG. 14 is used not only for sealing oil but also for sealing water and other fluids, and is most often used for sealing the rotating shaft 6. This type of oil seal 2 can guarantee a complete seal for a long time with low torque compared to other seal members, has a wide tolerance to shaft runout, and has a high limit speed, so it can withstand a relatively wide range of use. It has the following advantages.

However, on the other hand, since the lip portion 4 is thin and has an elongated cross-sectional shape in the axial direction, the force that tightens the shaft (tension force)
It's small enough for boat fishing. Therefore, the sealing pressure is low (2 to 3 kgr/cd at most), and if the pressure increases, problems such as lip protrusion occur, making it unusable.

On the other hand, gaskets such as the O-ring 8 and the X-ring 10 illustrated in FIGS. 15 and 16 have a relatively high sealing pressure and pressure resistance, but have a short lifespan.

Since seals on rotating shafts slide in a fixed area, compared to reciprocating movements like pistons, there is more heat accumulation and less heat radiation due to local temperature rises due to frictional heat. What is also important is that a sealing fluid film exists between the sealing surfaces of the seals such as the O-ring 8 and the It is difficult to do so. Even if a gap is created between the packing and the rotating shaft due to thermal deformation of the packing and a sealing fluid film exists, the gap is local and does not cover the entire circumference of the packing. As a result, when a gasket such as the O-ring 8 or the X-ring 10 is used for sealing a rotating body, the gasket itself is worn out due to frictional heat and the like, resulting in a short seal life.

In other words, in a packing for sealing a rotating body that is used between relatively rotating members, a thin film of sealing fluid must always exist between the rotating body and the seal line of the packing, and this part If the film is interrupted, wear occurs in that part, which has the disadvantage of shortening the seal life.

However, conventionally, only O-rings and X-rings have been known as simple sealing gaskets for sealing high-pressure fluid. Therefore, it is important to form a thin film of sealing fluid between the packing and the rotating body, but in order to seal high-pressure fluid, it is difficult to form a thin film of sealing fluid using conventional O I had no choice but to use a seal such as a ring or an X-ring.

Purpose of the Invention The present invention has been made in view of the above circumstances, and by improving the lubrication characteristics of the packing for sealing a rotating body, the life of the packing for sealing high-pressure fluid can be greatly increased by 11%. The goal is to improve.

Summary of the Invention In order to achieve the above object, the packing for sealing a rotating body according to the present invention has at least one strip continuous in the circumferential direction on the circumferential surface of the packing body made of an elastic material on the side that slides into contact with the rotating body. It is characterized in that it has an annular protrusion, and at least a part of the seal line of the annular protrusion is inclined at an arbitrary acute or obtuse angle with respect to the rotational axis of the rotating body.

According to the packing for sealing a rotating body according to the present invention, at least a part of the seal line of the annular protrusion formed on the circumferential surface of the packing main body has an arbitrary acute angle or an obtuse angle with respect to the rotational axis of the rotating body. Since it is inclined at an angle, the sliding speed V in the direction perpendicular to the seal line, in other words, in the leakage direction, has the relationship v=vφeO8θ with respect to the sliding speed V of the rotating body. In addition, the seal gap is hoc・μΦV・eO8θ/P, and as the fluid pressure P increases, the seal gap decreases, making it difficult to lubricate the seal surface, but in the present invention, the sliding in the leak direction Since the speed V can be increased, the seal gap becomes larger, the seal surface is better lubricated, and the seal life can be improved by a factor of 11. In the formula, θ is the angle between the seal line and the rotating shaft, and μ is the sealing angle. It is the viscosity coefficient of the fluid.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Fig. 1 is a longitudinal cross-sectional view of a packing for sealing a rotating body according to an embodiment of the present invention, Fig. 2 is a cross-sectional view showing an example of the use of the packing, and Figs. 3 to 9 are respective examples of other embodiments of the present invention. 10 to 13 are cross-sectional views showing other usage examples of the packing according to the present invention.

As shown in FIG. 1, a packing 20 for sealing a rotating body according to an embodiment of the present invention has a packing main body 22 having a generally rectangular cross section and a ring shape as a whole. At least one annular protrusion 24 continuous in the circumferential direction is integrally formed on the inner circumferential surface of the packing body 22. The ridgeline of this annular protrusion 24 comes into pressure contact with a rotating shaft 6 as a rotating body, which will be described later, and forms a seal line 26 as a sealing boundary line.

In the present invention, at least a part of the ridge line of the annular protrusion 24, that is, the seal line 26 is inclined at any acute or obtuse angle θ, θ'' with respect to the rotation axis 28 of the rotation shaft 6 as a rotating body. As such, the annular projection 24 is integrally formed on the inner peripheral surface of the packing body 22.

The acute angle θ of the seal line 26 with respect to the axis of rotation 28
may be any number of degrees as long as it is smaller than 90 degrees, but preferably 20 to 89.5 degrees, particularly preferably 75 to 89.5 degrees.

The material constituting such a packing 20 may be any material as long as it has elasticity, and is not particularly limited.
BR, nitrile rubber, urethane, acrylic, silicone rubber, fluororubber, fluororesin, etc. are used.

Next, an example of use of the rotating body seal packing 20 according to this embodiment will be explained based on FIG. 2.

As shown in FIG. 2, the packing 20 according to this embodiment is
The rotating shaft 6 as a rotating body and the casing 30 are installed in a packing groove 32 formed on the inner circumferential surface of the casing 30.
The gap between the casing and the casing is sealed to prevent the fluid 34 from leaking out of the casing.

Such a packing 20 for sealing a rotating body according to this embodiment
According to the above, the seal line 26 of the annular protrusion 24 formed on the circumferential surface of the packing body 22 is aligned with the rotation axis 28 of the rotation shaft 6.
As the rotating shaft 6 rotates, the sealing fluid 34 causes a gap between the annular protrusion 24 and the rotating shaft 6 due to its viscosity. the sealing fluid 34 near the seal line 26.
lubrication is possible. This lubrication theory can be explained, for example, as follows. That is, the sliding speed V in the direction perpendicular to the seal line 26, in other words in the leakage direction, is V-V with respect to the sliding speed V of the rotating shaft 6.
-eosθ.

""Also,
The seal gap is hcc・μ・v−CO8θ/P, and as the sealing fluid pressure P increases, the seal gap decreases and it becomes difficult to lubricate the seal surface. Compared to O-rings, etc., the sliding speed V in the leakage direction can be increased, so the seal gap becomes larger, and the sealing surface is better lubricated by the sealing fluid 34, so even if the fluid pressure is high, the sealing due to high pressure It can compensate for the reduction in clearance and greatly improve the seal life.In the formula, θ is the angle between the seal line and the rotating shaft, and μ is the viscosity coefficient of the sealed fluid.

Note that the present invention is not limited to the above-described embodiments, and can be variously modified within the scope of the present invention.

For example, as in a packing 20a shown in FIG. 3, the inclination direction of the seal line 26 in an annular projection 24a formed on the inner circumferential surface of a packing main body 22a may be changed midway in the circumferential direction. Further, the seal line 26 does not necessarily have to be a straight line, but may be a curved line. In the case of a curved line, at least a part of the tangent line of the seal line may be inclined at a predetermined acute or obtuse angle with respect to the axis of the rotating shaft. Packing skin 2 according to such an embodiment
Even if it is 0a, the intended purpose of the present invention can be achieved.

Further, the present invention provides a packing main body 2 as shown in FIG.
It is possible to apply the present invention to a packing 20b in which an annular projection 24b is formed on the outer peripheral surface 3b of the packing 20b. The packing 20b according to this embodiment is used for sealing when a rotating body comes into sliding contact with the outer periphery of the packing 20b.

FIG. 5 shows still another embodiment of the present invention, in which a normal annular projection 38 continuous in the circumferential direction on a plane perpendicular to the rotational axis 28 is formed on the outer circumferential surface 36 of the packing body 22c. A gasket 20c has an annular projection 24 similar to the annular projection shown in FIG. 1 formed on the inner circumferential surface of the gasket 22c.
is disclosed.

Further, in the present invention, as in the packing 20d shown in FIG. 6, the outer peripheral surface of the packing main body 22d does not necessarily have to have a cylindrical side surface shape, but may have a rounded shape along the rotation axis 28 direction. It's okay to have one.

Furthermore, in the present invention, the packing 2 shown in FIGS.
0e, the inner peripheral surface of the packing body 22e (or
Although not shown, two or more annular protrusions 24 may be formed on the outer peripheral surface. At that time, as shown in Figure 8,
A drain hole 40 may be formed in the packing body 22e to communicate the gap between each annular projection 24 and the outer circumferential surface side of the packing body 22e.

Further, as shown in FIG. 9, each seal line 24 in each annular projection 24, 24 formed on the packing body 22e
The angles of inclination with respect to the axis of rotation 28 may be made different.

Furthermore, as shown in FIGS. 10 to 12, the packing 2Or, 20g according to the present invention may not be used alone, but may be used by being attached to the packing groove together with the backup ring 42. In the usage example shown in FIG. 10, a backup ring 42 having a simple rectangular cross section is attached to the end face of the gasket 2Or. In the usage example shown in FIG. 11, a backup ring 42a having a cylindrical protrusion 44 is attached to the end face of the packing 2Of'.

The amount of axial protrusion of the cylindrical projection 44 is changed depending on the distance of the annular projection 24 from the end surface of the packing body 22r.

In the usage example shown in FIG. 12, a cylindrical backup ring 42b is attached between two annular protrusions 24 formed on the packing 20g.

Further, 20 to 20 g of the packing according to the present invention may be used alone, but as shown in FIG. 13, two or more may be used.

In addition, in the above-mentioned embodiment, the packing main bodies 22 to 22f
Although the cross-sectional shape of ' is approximately rectangular, the present invention is not limited to this, and other cross-sectional shapes such as circular, elliptical, and polygonal shapes may be used.

Further, it is possible to use the packing according to the present invention for purposes other than sealing a rotating body.

As described in detail, according to the present invention, a seal gap proportional to the sliding speed V is created in the gap (sliding surface) between the annular protrusion of the packing and the rotating body. As a result, the life of the seal is significantly improved compared to conventional O-rings and X-rings. According to experiments, 10
Improved by ~100 times.

Furthermore, it is now possible to seal rotating parts that conventionally could not be used with oil seals due to high pressure, making the sealing device more compact.

Furthermore, the seal of the present invention can be used in the same manner as conventional O-rings, X-rings, etc., so it can be said to be an extremely simple seal.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a packing for sealing a rotating body according to an embodiment of the present invention, Fig. 2 is a cross-sectional view showing an example of the use of the packing, and Figs. 3 to 9 are respective examples of other embodiments of the present invention. FIGS. 10 to 13 are sectional views showing other usage examples of the packing according to the present invention, and FIGS. 14 to 16 are sectional views showing how the conventional packing is used. be. 6...Rotation axis

Claims (1)

[Scope of Claims] 1) At least one annular protrusion continuous in the circumferential direction is provided on the circumferential surface of the packing body made of an elastic material on the side that comes into sliding contact with the rotating body, and at least a portion of the seal line of the annular protrusion is provided. is a packing for sealing a rotating body, which is inclined at an arbitrary acute or obtuse angle with respect to the axis of rotation of the rotating body. 2) The seal line of the annular protrusion is a curved line, and at least a part of the tangent line of the seal line is inclined at an arbitrary acute or obtuse angle with respect to the rotational axis of the rotating body. The packing for a rotating body seal according to item 1.