JPH11336908A - Seal material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal material which has slow starting resistance and excellent abrasion resistance and is hardly forced out by forming a sliding seal side as a high hardness part, and also forming the inner end side of a recessed groove as a low hardness part, and integrally forming two parts in the seal material whose cross sectional shape is a non-circular shape. SOLUTION: This seal material S which is a so-called X ring whose cross sectional shape is an X shape is mounted in the recessed groove 2 of a first member (mounting member) 1 such as a pump casing and a cylinder head. In this case, in the seal material S, the inner end side of the recessed groove 2 is formed as a low hardness part 5, and also a sliding seal side 6 sealing by sliding on a second member (counterpart) 3 such as a piston rod and a cylinder tube is formed as a high hardness part 4, and they are integrally formed. For example, the rubber hardness of the high hardness part 4 is set from 80 to 95 degrees, and the rubber hardness of the low hardness part 5 is set from 50 to 75 degrees. The cross sectional area ratio to the high hardness part 4 and low hardness part 5 is set to from (20:80) to (80:20). Both the members 1, 3 perform linear reciprocating motion and rotational motion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sealing material.

[0002]

2. Description of the Related Art Conventionally, as a sealing material for sealing a liquid, a gas or the like, various cross-sectional shapes such as an O-ring, an X-ring, a D-ring, a U-packing, a Y-packing, and the same material / material are used.
Materials having the same hardness have been widely used (hereinafter referred to as "one-layer sealing material"). Conventionally, (O-ring,
A seal material having a two-part assembly structure (hereinafter referred to as a "combination seal material") is used, which includes a rubber seal body (such as an X ring, a T ring, and a U packing) and a synthetic resin backup ring and a slipper ring. Have been. That is, in this combined sealing material, two parts having different hardnesses (or materials) such as a backup main body and a slipper ring are assembled and mounted in the groove.

[0003]

In the conventional one-layer sealing material, when the rubber hardness is low, the starting resistance is small, but the abrasion resistance is poor and the protrusion resistance is also poor. That is, FIG. 8 exemplifies a case where the X-ring 31 is used as a single-layer sealing material. In FIG. 8, (A) shows a mounted state (sealing fluid pressure is zero).
(B) shows a state in which a low pressure P ₁ is applied, and (C) shows a state in which a relatively high pressure P ₂ is applied. A graph (contact pressure distribution diagram) is plotted on the vertical axis, taking the contact surface pressure P with the counterpart member (piston rod or inner surface of the cylinder tube) 32 (moving linearly and / or rotationally) taking the position in the center direction. Shown.

FIG. 8 shows that the contact surface pressure P is relatively small (low) and the starting resistance is small. However, FIG.
When the high pressure P ₂ acts as shown in FIG.
Is formed in the gap 35 between the mounting member 34 and the mating member 32,
A protrusion 36 (of the lip) is generated. In addition, it can be expected that wear is large when rubber hardness is low. Conversely, if the rubber hardness of the sealing material is higher, the protrusion resistance and abrasion resistance are good, but there is a disadvantage that the starting resistance is large.

That is, FIG. 9 exemplifies the case of the X-ring 31 similarly to FIG. 8, and shows the contact surface pressure P in the mounted state (A), the low pressure operation state (B), and the high pressure operation state (C). FIG. 9 shows that the contact surface pressure P is significantly larger than that of FIG.
It can be seen that the resistance ─── generated by the X-ring 31 as the relative movement of 34 begins is significantly greater.

On the other hand, the X-ring 31 made of a rubber material having a high hardness (as shown in FIG. 9) is reduced in the crushing allowance, so that a groove is formed.
In order to reduce the starting resistance by lowering the repulsive force (elastic force) when mounted inside 33, it is necessary to make the dimensional accuracy of the sealing material (X ring) 31 and the dimensional accuracy of the concave groove 33 severe. However, there is another problem that the production becomes difficult, the cost is increased, and the life is shortened due to abrasion due to the small crushing allowance.

As described above, it has been difficult to satisfy all the conditions required for a sealing material, such as a low sealing resistance, good wear resistance, and good protrusion resistance, with a single-layer sealing material.

Although the above-mentioned combination sealing material can solve the above-mentioned disadvantages of the sealing material, it is difficult to handle because it is composed of a plurality of parts. There are drawbacks such as the need to increase the groove size (need to increase the sealing material space).

It is an object of the present invention to provide easy handling, excellent mounting in a groove, compactness, easy management of a sealing material, low starting resistance, and excellent wear resistance. An object of the present invention is to provide a sealing material that does not easily protrude (a sealing material having good resistance to protruding).

[0010]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a sealing material having a non-circular cross-sectional shape, in which the sliding sealing side is made into a high hardness portion and the deep groove side is made into a low hardness portion. Is molded. Also, the cross-sectional area ratio of the high hardness part and the low hardness part
(20:80) to (80:20).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on the illustrated embodiments.

In FIG. 1, a so-called X-ring having an X-shaped cross section is exemplified as a sealing material S. Reference numeral 1 denotes a first member (mounting member) having an annular groove 2 and 3 denotes a second member. For example, the first member (attachment member) 1 is a pump casing, a cylinder head or a piston,
The member (counterpart) 3 corresponds to the output rotary shaft, the piston rod, and the cylinder tube (inner surface), respectively.

The sealing material S is mounted in the groove 2 of the first member (mounting member) 1 as shown in FIG. The sliding sealing side 6 which performs a sealing action while sliding on the
As one piece. In other words, the sealing material S is a “two-layer sealing material”.

The second member 3 and the first member 1 relatively perform a linear reciprocating motion, a rotating motion, or a combined motion of the two.
Do. As the material of the high-hardness portion 4 and the low-hardness portion 5 which are integrally molded, rubber, plastic, a composite material of them, or a material mixed with various kinds of wear-resistant powder can be selected.
For example, the rubber hardness of the high hardness part 4 is set to 80 to 95 degrees, and the rubber hardness of the low hardness part 5 is set to 50 to 75 degrees. However, rubber hardness is JI
It is the rubber hardness measured by SHS.

When the cross-sectional area of the high hardness part 4 is Z ₄ and the cross-sectional area of the low hardness part 5 is Z ₅ , in the example of FIG.
Z _4: shows the case of a 50: Z ₅ = 50. However, this ratio: the (Z ₄ Z ₅₎ is operating conditions (pressure, stroke, speed or sliding speed, type of Fluid, temperature, etc.),
It can be increased or decreased.

However, when (Z ₄ : Z ₅ ) is changed from (20:80) to
It is better to set it in the range (80:20). The reason is that if it is out of this range, the production becomes difficult and the problem of the sealing material is more likely to appear.

FIG. 7 shows the conventional low-hardness single-layer seal material 31 shown in FIG. 8 and the conventional high-hardness single-layer seal material shown in FIG. Lumber
Similarly to 31, the mounted state (A) and the low pressure action state (B)
It is a graph figure (pressure distribution figure) of the contact surface pressure P in each state of a high pressure action state (C).

That is, the sealing material S according to one embodiment of the present invention.
Is compared with the conventional one-layer sealing material 31 shown in FIGS. 8 and 9, the following becomes clear. First, even in the high pressure operating state (C), the protrusion into the gap 8 between the first member 1 and the second member 3 is caused by the fact that the high hardness portion 5 is disposed on the sliding sealing side 6. Does not occur. As is clear from comparison with the graphs (pressure distribution diagrams) shown in FIGS. 8 and 9 in the same unit (scale), the contact pressure P in FIG.
It is much smaller than (C) and therefore the starting resistance is also small. Of course, since the high hardness portion 5 is in sliding contact with the second member (counterpart member) 3, wear is small and the seal life is extended.

In short, the sealing material S (X-ring) according to the present invention has a low starting resistance, is excellent in abrasion resistance, and is also excellent in resistance to protrusion. In addition, as compared with the conventional combination sealing material, the X-ring (seal material S) according to the present invention is low in cost, easy to mount in the concave groove 2, compact, does not cause mounting errors, and manages sealing components. It has tremendous advantages such as ease of operation.

Next, FIGS. 2 to 6 show another embodiment of the present invention in a cross section of a main part. FIG. 2 shows the rounded X-ring type sealing material S, and FIG. 3 shows the rounded X-ring type sealing material S. The cross-sectional area Z ₄ of the high-hardness portion 4 the ratio of the cross-sectional area Z ₅ of the low hardness portion 5, in FIG. 2 as (50:50), 3, exemplifies the case of about (30:70) ing.

4 is a D-ring type, FIG. 5 is a square ring type, and FIG. 6 is a U-packing type. It can be seen that any of the cross-sectional shapes shown in FIGS. 1 to 6 are non-circular shapes in which rotation (twisting) hardly occurs in the rectangular groove 2. Due to such non-circular shape, the mating member (second member) 3
The high hardness part 4 can be arranged on the side 6 to be slid and sealed.

[0022]

According to the present invention, the following significant effects can be obtained by the above-described structure.

The crushing allowance (reaction force) is small, and the mounting work into the concave groove 2 is easy. The starting resistance of a fluid device such as a pump, a cylinder or a valve using the sealing material S of the present invention is small. The wear on the sliding sealing side 6 is small and the life is long. The resistance to protrusion is improved. It is not necessary to improve the dimensional accuracy of the sealing material S itself and the groove 2 in order to reduce the starting resistance. Compared with the combined sealing material, the cost is low (because the sealing material S of the present invention is a single piece), the size is small, and the handling and management of parts are easy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing still another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing still another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing another embodiment of the present invention.

FIG. 7 is an operation explanatory diagram and pressure distribution diagram of the sealing material shown in FIG. 1;

FIG. 8 is an operation explanatory diagram and a pressure distribution diagram of an example of a conventional sealing material.

FIG. 9 is an explanatory diagram and a pressure distribution diagram of another example of a conventional sealing material.

[Explanation of symbols]

 2 Concave groove 4 High hardness part 5 Low hardness part 6 Sliding sealing side S Sealing material

Claims (2)

[Claims] In a sealing material having a non-circular cross-sectional shape,
A sealing material formed integrally with a sliding seal side as a high hardness portion and a deep groove side as a low hardness portion. 2. The sectional area ratio of a high hardness part and a low hardness part is
2. The sealing material according to claim 1, wherein (20:80) to (80:20) are set.