JPS598035Y2 - Patsukin - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a packing for sealing.

More specifically, the present invention relates to a packing used in a sealing device for a rotating or reciprocating rotating part, for example, a packing for a sealing part of a universal rotary joint in a hydraulic circuit of a construction machine or the like.

Packing is used in the sealing part of center swivel joints or universal rotary joints used in hydraulic circuits of construction machinery and the like.

Conventionally, a ring-shaped packing made of a single rubber material is known as a packing used in this type of center swivel joint or universal rotary pipe joint.

These packings have a large frictional resistance on the sliding surface between the rotating shaft and the packing, causing abnormal wear and resulting in a problem in sealing performance.

Furthermore, as a recently known packing, a packing shown in FIG. 1 is used.

FIG. 1 shows a cross section of the packing installed. It has a casing 2 that is penetrated through the rotor 1, and a packing groove 4 cut on the circumferential surface of the through hole of the casing 2 is filled with rubber material. A square ring 6 made of aluminum and a square ring-shaped sealing member 5 made of a synthetic resin material that slides on the rotor 1 on its inner periphery are combined and tightly attached.

A gap 3 between the rotor 1 and the casing 2 is partitioned off by a sealing member 5 to prevent fluid from leaking from the gap 3.

However, since the sealing member 5 is made of a synthetic resin material in consideration of wear resistance, friction resistance, etc., it has poor trackability with respect to the rotating shaft and has a problem in sealing performance.

FIG. 2 shows the installation state shown in FIG. 1 in use when pressure P is applied.

In the pressure distribution diagram shown in FIG. 2, the sealing pressure on the pressure receiving side is P.

and low. Then, the pressure gradually increases toward the side opposite to the pressure receiving side, forming a gradient A.

However, since this gradient A is formed, even if the side opposite to the pressure receiving side is high, the pressure fluid that has already entered forms a wedge shape and reaches the side opposite the pressure receiving as if pushing the sealing surface of the sealing member 5 apart.

As a result, the sealing ability of the packing is reduced.

In particular, when low pressure fluid acts on the packing, Po
Since it is even smaller, pressure fluid can easily penetrate and the sealing condition is significantly deteriorated, which is a big problem.

On the contrary, when high-pressure fluid acts, the fluid pressure acts on the side surface of the square ring 6 and presses the square ring 6 in the radial direction, so this force presses the sealing member 5 against the rotor 1 and seals it. This poses a major problem of rapid surface wear and eventual damage.

The present invention was developed in view of the above-mentioned problems, and its technical challenges are to demonstrate sealing ability regardless of the level of fluid pressure, and to ensure that the sliding member does not close even when high-pressure fluid is applied. The purpose is to prevent damage to the sealing surface.

The technical means of the present invention for solving the above-mentioned technical problems is constructed as follows.

A sealing member is made of a resin material into a square ring shape, and one of the inner circumferential surface and the outer circumferential surface is a sealing surface and the other is a fixing surface, and a rubber-like elastic material is attached to the fixing surface side of the sealing member to form an annular body. The manufactured supports are combined, and an annular groove is provided in the sealing surface of the sealing member to form the sealing surface into a first sealing part and a second sealing part, and the sealing part is formed into a first sealing part and a second sealing part. At least the axial width of the sealing portion opposite to the pressure receiving side is made smaller than the axial width of the groove.

The support is made of a rubber-like elastic material, and in particular, synthetic rubber can be widely used depending on its suitability.

Further, it is preferable that the sealing member is made of a resin material having a certain degree of elasticity, low abrasion resistance, and excellent abrasion resistance, such as a fluororesin.

With this structure, the deformation pressure of the rubber-like elastic material due to pressure is used as a support function, and the sealing member is pressed to increase the sealing force, and the sealing surface with the rotor has a low frictional resistance. It is sealed using abrasion-resistant synthetic resin.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 3 is a half-sectional view of the packing according to the present invention installed.

Now, 1 is the rotor, 2 is the casing, and the casing 2
An annular packing groove 16 is provided on the inner periphery of the hole penetrated through the rotor 1, and a packing is mounted in this packing groove 16.

This packing is made of a ring-shaped support 12 made of rubber material, which is a rubber-like elastic body, and a square ring-shaped sealing surface 14 made of fluororesin (trade name: Raeflon), which is a resin material. and a sealing member 11 having a fixing surface 15.
It is connected with the inside.

The axial width of the sealing surface 14 of this sealing member 11 is
In this embodiment, the radial thickness is larger than that of the radial thickness of the radial direction.

A groove 13 is provided in the sealing surface 14 in an annular shape.

By providing the groove 13 in the sealing surface 14, the sealing surface 14 is formed into a first sealing part 21 and a second sealing part 22, as shown in FIG.

Furthermore, the axial widths of the first sealing part 21 and the second sealing part 22 are smaller than the axial width of the groove 13.

This is because the fluid acts alternately from the axial side of the packing, so the axial widths of the first and second sealing parts 21 are both equal to the groove 1.
Although the width is smaller than the axial width in Figure 3, if fluid pressure acts only from one side of the packing in the axial direction, the sealing part opposite to the pressure-receiving side of the packing, for example, the pressure shown in Figure 5. In the operating state, only the axial width of the second sealing portion 22 may be smaller than the axial width of the groove 13.

Note that a gap 3 exists between the rotor 1 and the casing 2.

In FIG. 4, a packing groove 16 is cut into the rotor 1.

A fixed surface 15 of a sealing member 11 made of a fluororesin material is concentrically connected to the outer periphery of an annular support 12 made of a synthetic rubber material to form a packing, and this packing is installed in a packing groove 16. .

The sealing surface 14 of this packing is provided on the outer peripheral surface so as to slide on the casing 2, and the sealing surface 14 has a groove 13.
are arranged in a ring.

The rest of the structure is substantially the same as in FIG. 3.

The present invention constructed as described above has the following effects.

FIG. 5 is a state diagram in which pressure P is applied to the packing 10, the same as FIG. 3.

As a result of experiments, when the fluid pressure P is applied at low pressure (approximately 80 kg/- or less), the elastic force of the support body 12 accounts for a large proportion, and the pressure distribution of the sealing member 11 against the rotor 1 is determined as follows.
A pressure distribution diagram as shown in FIG. 5 will be obtained.

In the first sealing part 21, the initial sealing pressure P on the pressure receiving side X is the pressure receiving side sealing pressure P shown in FIG.

The pressure fluid enters the sealing surface 14 in the form of a wedge in order to form a pressure distribution similar to that of the gradient A.

However, when this infiltrated pressure fluid infiltrates into the groove 13, the wedge-shaped intrusion of the fluid is destroyed by the groove 13, and it is retained within the groove 13.

At the same time, since fluid pressure also acts on the side surface of the packing 10, the support body 12 is pressed by the fluid pressure to the side surface of the packing groove 16 opposite to the pressure receiving side, and is elastically deformed and tries to expand in the radial direction, resulting in the second sealing part. 22 toward the rotor 1 side, thereby increasing the sealing force of the second sealing portion 22.

Since the sealing surface of the second sealing part 22 does not have a pressure distribution having a gradient like the first sealing part 21 shown in FIG. 5, even if the sealing member 11 is made of resin material, Preventing pressure fluid from entering the sealing surface in a wedge shape,
A child is formed that exhibits a sealing effect.

However, if the groove 13 is small in the axial direction, the influence of the tapered shape of the first sealing part 21 due to the wedge-shaped fluid reaches the second sealing part 22, and the wedge-shaped fluid also forms in the second sealing part 22. This will allow fluid ingress.

Therefore, if the axial width of the groove 13 is made larger than the axial width of the second sealing part 22, this influence will hardly be exerted.

Next, when high fluid pressure is applied to the packing, the sealing surface of the conventional sealing member 11 on the opposite side of the pressure receiving side comes into increasingly pressure contact with the rotor 1 for the reasons mentioned above, causing rapid wear and eventually damage. .

However, since the packing of the present invention is provided with the groove 13 on the sealing surface, when high pressure (experimentally 80 kg/Cm or more) is applied, fluid pressure also acts on the bottom peripheral surface of the groove 13. The sealing member 11 is then elastically deformed to have an arched cross-section in the outer radial direction.

In particular, since the axial width of the groove 11 is larger than the axial width of the second sealing part 22, the oil film that enters the sealing surface of the first sealing part 21 and the bottom peripheral surface of the groove 13 are The accumulated and acting fluid pressure refers to the pressure receiving area of the bottom peripheral surface of the groove 13 and the pressure receiving area of the sealing surface of the second sealing part 22, so that the second sealing part 22 is expanded outward. This facilitates the formation of an extremely thin oil film on the sealing surface of the second sealing portion 22.

As a result, the second sealing part 22 is strongly pressed against the rotor 1, effectively preventing the sealing surface from being rapidly worn out.

This has also been experimentally confirmed that the axial direction of the groove 13 is connected to the second sealing part 22.
It has been found that wear damage to the second sealing portion 22 is significantly reduced by making the width larger than the width of the second sealing portion 22 .

Note that the axial width dimension of the sealing portion 22 of the packing of the present invention is roughly determined by the width dimension of the packing and the magnitude of the fluid pressure acting on it, and it should be a small medium dimension that cannot withstand the fluid pressure. isn't it.

Further, the groove 13 is provided in the center of the sealing surface 14 in the axial direction, as an example of a case where pressure is applied alternately to the pressure receiving side X and the opposite pressure receiving side Y, and the groove 13 is not limited to the center. .

As described above, the packing of the present invention exhibits sealing performance and durability against the effects of both low and high pressures.

[Brief explanation of the drawing]

Figure 1 is a partial cross-sectional view showing the installation state of a conventional packing.
Figure 2 is a partial cross-sectional view and pressure distribution diagram of the state of the packing when pressure is applied in Figure 1, Figures 3 and 4 are partial cross-sectional views of the packing of the present invention in the installed state, and Figure 5. 3 is a partial sectional view and pressure distribution diagram of the state of the packing when pressure is applied in FIG. 3. 10...Packing, 11...Sealing member, 12...Support, 13...Groove, 14
..., Sealing surface, 15... Adhering surface, 21...
...first sealing part, 22...second sealing part,
A...Gradient, X...Pressure receiving side, Y...
...Opposite pressure receiving side.

Claims (1)

[Scope of utility model registration request] A sealing member 11 is made of a resin material into a square ring shape, and one of the inner circumferential surface and the outer circumferential surface is the sealing surface 14 and the other is the fixing surface 15. A rubber-like elastic material is provided on the fixing surface 15 side of the sealing member 11. A support body 12 made of an annular body and elastically deformed in the radial direction under the action of a pressure fluid is connected substantially concentrically, and an annular groove 13 is provided in the sealing surface 14 of the sealing member 11 to form a sealing surface 14. The first sealing part 21 and the second sealing part 2
2, and the axial width dimension of at least the sealing portion opposite to the pressure receiving side of the sealing portions 21 and 22 is set to the groove 1.
Packing smaller than the axial width of item 3.