JPH0235273A - Sealing device - Google Patents

Abstract

PURPOSE:To sufficiently seal the liquid which possesses little lubricity such as water by press-fitting the second seal into a vacant place divided by the axial direction part and the radial direction part of the reinforcing ring of the first seal and allowing the outer peripheral side part of the second seal to contact the inner peripheral surface of the axial direction part of the reinforcing ring. CONSTITUTION:The first seal 20 is fixed by the press-fitting into a housing 1 or using snap ring, etc., by the action of a reinforcing ring 25 made of metal. While, the second seal 30 which is press-fitted into a space 22 surrounded by the reinforcing ring 25 of the first seal 20 has a recessed part or a bottom part 35 having a sufficient space between an outer peripheral side part 32 and an inner peripheral side lip 31, and the lubricant holding quantity is increased, and also the liquid scraped off by the second seal 30 can be sufficiently stored. Further, since the direct contact with the metal part of the housing 1 with the water which is sealed is prevented, the generation of rust is prevented. Further, the deformation of the seal due to the friction of the seal 30 and the deformation of the lip 21 of the seal 20 do not interfere with each other, the sealing effect of each lip is developed.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applied to a rotary part of a fluid pressure cylinder that mainly moves reciprocatingly, and is applied from the outside of the cylinder to the surface of the rotor 1 (=J). Prevent foreign matter such as dust and liquid droplets, as well as dust or external liquid (sometimes under pressure), from entering the Solink when the lot is operated in liquid outside the cylinder. The present invention relates to a sealing device for preventing

(Prior Art) Fig. 1 shows a conventional dust seal 3 in which a general dust seal 3 is attached in a housing 1, in which an elastic material such as synthetic rubber or synthetic resin such as thermoplastic elastomer is bonded to a conventional metal reinforcing ring 5. It is a sectional view showing a state. Note that the lip 6 is shown in a free state and is not shown in a deformed state due to contact with the lot 2. Reference numeral 7 indicates an oil seal lip.

Conventionally, the general seals 1 to 3 shown in Fig. 1 were sufficient to seal water entering from the outside into the rond part of a fluid pressure cylinder, etc.; Rod 2 extending from the cylinder (shown, U)
When the rod 2 is exposed to a large amount of water, or when the rod 2 is operated underwater, the lubricant (lubricating oil) on the surface of the rod may be washed away by water and the lip 6 of the dust seal 3. As a result, the lubricating condition between the lip 6 and the rod surface is poor, making it impossible to maintain sealing performance and promoting wear on the tip of the lip 6. As a result, water enters the inside of the cylinder and causes a failure of the hydraulic equipment. Something happened.

Particularly when the lot 2 comes into contact with an external liquid such as a water-soluble cutting fluid, the cutting fluid itself has poor lubricity and easily washes off the lubricating oil on the surface of the rotor 12, resulting in a significantly poor lubrication condition between the lip 6 and the surface of the lot. As a result, the wear of the tip of the professional is accelerated and cutting fluid leaks into the hydraulic oil, causing problems such as emulsification and deterioration of the hydraulic oil.

To solve these problems, even in the conventional case, as shown in FIG. 2, a second seal 4 that does not come into direct contact with external water, etc. can be incorporated inside the dust seal, and its inner circumferential lip 8 can
A method is used to seal water and the like that have entered through the lip 6 of the dust seal 3.

Note that FIG. 2 shows a single-lip type first dust seal 3 which is not shown in FIG. 70) i, ii d1
- Shows a sealing device constructed by incorporating second loops 4 made of a material into separate mounting grooves.

According to the configuration shown in FIG. 2, the lubricant can be stored in the space 13 between the dust seal 3, which is the first seal, and the second seal 4, so that wear on the tip of the lip due to lack of lubrication is considerably reduced. Further, the lip 8 of the second seal 4 seals water etc. to such an extent that there is no problem in normal use.

However, this time, the housing 1 or the seal mounting groove 10, and the space 13 are damaged by the water sealed in this way.
Rust occurs on the metal part of the seal, and this rust flakes off and adheres to the surface of the rod, causing the lip 8 to wear out. Also, depending on the movement conditions, the lip 8 may wear out in the mounting groove 10 of the packing that constitutes the second seal 4. has poor stability, making it difficult to maintain effective sealing performance over a long period of time.

In addition, in this method of installing a double seal device, the two seals are installed in separate grooves, which increases the number of man-hours required to process the housing, incorporate the seals, or increase the housing space. is not necessarily the best configuration.

(Problems to be Solved by the Invention) Thus, it is an object of the present invention to provide a sealing device that improves the problems associated with sealing liquids with poor lubricity such as water, which is the king of conventional seals.

(Another Means to Solve the Problems) The gist of the present invention is to provide reinforcement having a cross-sectional shape of approximately 17 or J7, which is almost entirely surrounded by an elastic material such as synthetic rubber or synthetic resin, as shown in FIG. A first seal 20 comprising a ring 25 and a knoll lip 21 provided on the inner peripheral side of a radial portion 26 of the reinforcing ring 25 and protruding outward in the axial direction and abutting the surface of the rod 2; It has a second seal 30 made of an elastic material such as synthetic rubber or synthetic resin and has an inner circumferential side ring 31 that comes into contact with the surface, and the second seal 30 is a reinforcing ring of the first seal 20. The second seal 30 is press-fitted into a space 22 defined by an axial portion 27 and a radial portion 26 of the second seal 30 , and the outer circumferential portion 32 of the second seal 30 is inserted into the inner axial portion 27 of the reinforcing ring 25 of the first seal 20 . This is a unique sealing device configured to abut against the circumferential surface.

(effect) Next, the present invention will be described in further detail with reference to the accompanying drawings.

As shown in FIG. 3, the sealing device according to the present invention includes:
A first seal 2 formed by adhering a metal reinforcing ring 25 having an L-shape or a J7 cross-sectional shape with an elastic material such as synthetic rubber or synthetic resin so as to surround almost the entire part thereof.
0 is set. On the inner peripheral side of the radial portion 26 of the reinforcing ring 25 of the first seal 20, a
:1 A seal lip 21 that comes into contact with the surface of the rod 2 is provided. A second seal 30 is press-fitted into the space 22 formed by the axial portion 27 and the radial portion 26 of the reinforcing ring 25 . The second seal 30 is made of an elastic material such as synthetic rubber or synthetic resin, and includes an outer lip 32 and an inner lip 31.

In the sealing device of the present invention having such a configuration,
The first seal 20 is fixed to the housing I by press fitting or a snap ring by the action of a metal reinforcing ring 25. - On the other hand, the second seal 30 press-fitted into the cavity 22 surrounded by the reinforcing ring 25 of the first seal 20 is
2 and the inner circumference side lip 31 is provided with a recess or trough 35 with sufficient volume, so a large amount of lubricant can be retained.
In addition, the liquid scraped off by the second seal 30 can be sufficiently stored, and since the sealed water does not come into direct contact with the metal parts of the housing 1, rust does not occur.

Further, since the deformation of the seal due to friction of the second seal 30 or the deformation of the lip 21 of the first seal 20 do not interfere with each other, the sealing effect of each lip is fully exhibited.
It can also perform satisfactorily in sealing fluids with poor lubricity such as water.

FIG. 4 shows another modified example of the sealing device of the present invention, in which the recess 2 in the inner peripheral surface of the axial portion 27 of the first seal 20 is shown.
4 to fit the convex portion 33 of the second seal 30, and then
Valley 3 of second seal 30 of radial portion 26 of seal 20
5 shows a sealing device in which an annular convex portion 23 is provided on the surface facing 5.

According to the embodiment of the sealing device according to the present invention shown in FIG.
The outer circumferential surface portion and the convex portion 33 of the outer circumferential side portion or the top portion 34 of the outer circumferential lip portion of the second seal 30 are shaped so that the unevenness matches each other, and the outer circumferential side portion of the second seal 30 or the outer circumferential lip The portion is configured to fit into the recess (or vice versa). Therefore, when the sealing device is assembled into the housing 1, the first
The seal 20 and the second seal 30 can be easily attached together, and the second seal 30 is prevented from falling off during assembly.

Furthermore, an outer circumferential portion of the second seal 30 ( By providing the annular convex portion 23 that supports the outer circumferential lip 32, deformation of the second seal 30 due to friction can be actively suppressed, increasing the stability of the second seal 30 and maintaining sealing performance. , can be improved.

According to another aspect, the first sill and the second sill as described above may be
The structure of the seal may be as follows.

That is, so that the second seal is compressed in the axial direction when installed, the second seal is elastically held by a method such as providing annular protrusions on each axial surface of the second seal to maintain the stability of the second seal and its sole. The effect may be further enhanced (fifth
Figures 5a and 5b).

That is, FIG. 5 shows still another aspect of the present invention, which is a sealing device in which annular projections are installed on each axial surface of the outer circumference of the main body portion of the second seal 30. As shown in FIG.

Fifth. '' and FIG. 5b are cross-sectional views of the first seal 20 and the second noon 30 of the sealing device shown in FIG. 5, respectively, in a free state.

The shape stability against friction of the second seal 30 must be compatible with a wide range of usage conditions depending on lubrication conditions, motion conditions, etc. Therefore, as shown in FIG.
7, and the collar portion 57 is connected to the axial portion 27 of the first sill 20.
By making contact with the bottom surface of the second seal 30, the second seal 30 is pressed against the side surface 11 of the mounting a1, and the second seal 30 is substantially prevented from being deformed due to changes in motion conditions such as frictional force. The stability of the seal can be further improved.

Further, as shown in FIG. 5a, a plurality of annular projections 49, 49' are provided on the outer peripheral surface of the axial portion 27 of the first seal 20, and the annular projections 49' are located on the outside of the cylinder.
By configuring the diameter and width to be larger than that of the inner protrusion 49, the sealing performance at the outer circumferential fixing surface 12 of the groove (see Fig. 5) is improved without impairing the fit. be able to.

Further, as can be seen from FIG. 5h, one or more of By numbering the annular protrusions 58, 58' and 58'', there is no margin for accuracy in the axial dimensions of the first seal 20 and the second seal 30, and the relationship between the housing 1 and the sealing device can be improved. The sealing performance at the groove side surface 11, which is the abutting portion, can be improved.

By the way, the fluid scraped off by the seal lip 31, which is the second lip, adheres to the rod 2 and returns to the outside of the cylinder when Rono I extends (extends to the outside) in a reversible manner. However, the top of the inner circumferential lip 31 of the second seal 30 hits the annular convex portion 23 (see Fig. 4) or the radial portion 26 or jaw portion 48 (see Fig. 5a) of the first seal due to lip friction. If they come into contact due to deformation, the fluid accumulated in the recess or trough 35 of the second seal 30 will be sealed at the abutment between the top of the inner lip 3 and the jaw 48, and the rod 2, it becomes difficult for the fluid to be discharged to the outside of the cylinder, and the fluid stored in this part increases and has pressure, which tends to deteriorate the sealing performance of the second seal 30.

In order to drain the fluid accumulated in such a recess or valley 35, the inner gauging knob 31 of the second seal 30 is used.
A plurality of fluid pressure passages 59 formed by protrusions or grooves extending in the radial direction are provided on the top of the second seal 30 so that the sealing performance of the second seal 30 is not impaired.

See Figure 5b.

Figure 6 shows the inner lip 31 extending outward and the inner lip 31 of the cylinder. J! FIG. 3 is a schematic cross-sectional view of a sealing device in which a second seal 30 of a dual-lip type is combined with an oil seal lithop 72 for sealing body pressure.

According to the embodiment shown in FIG. 6, as in the case of FIG. 5, the annular projection 23 is used on the inner periphery instead of the annular projection 23 shown in FIG. A jaw 48 is provided which extends to the side end. The inner lip 31 is set to be shorter in the axial direction than the outer circumferential portion 32, so that the jaw portion 4
8 and a slight gap. As explained in FIG. 5b, the top of the inner lip 31 is provided with a plurality of fluid pressure passages 59 formed by protrusions or radially extending grooves, and the jaw 48 is also provided with fluid pressure passages 59. 69 is provided to make it easier to drain the fluid accumulated in the recess, that is, the trough 35. Fluid pressure passage 59.69
This objective can also be achieved by providing at least one of the top of the inner lip 31 of the second seal 30 described above or the jaw 48 of the first seal 20.

Furthermore, by providing an oil seal lip 72 which is a third lip protruding in the opposite direction to the axial direction from the lip 21 of the first seal on the inner circumferential surface of the second seal 30 on the bottom side of the main body,
Seal the pressure of the working fluid inside the cylinder, No. 17
- A one-piece seal consisting of the seal 20 and the second seal 3o, which simultaneously prevents the intrusion of fluids such as water from the outside and seals the working pressure fluid inside the cylinder, making it extremely compact.
・A sealing device can be obtained. By providing a fluid pressure passage 79 at the top of the oil seal lip 72, which is this third lip, the oil seal lip 72
The sealing properties will not be compromised. See Figure 6.

In a cylinder device used at high pressure, an oil film that leaks from the third lip, the oil seal lip 72, and a rod seal (not shown in the figure) installed inside the cylinder is sealed. Acts as a double seal to prevent leakage to the outside of the cylinder.

(Effects of the Invention) As detailed above, the sealing device of the present invention consists of two dust seals, and the knee seals are fitted in advance.
It can be attached to the housing with two "combined" parts. Therefore, the occurrence of rust on the housing 1, the number of man-hours for machining the housing part, the space, and the installation workability including the 8J1 of the dust I/seal are significantly improved.

Space 35 (trough) between the first lip and the second lip
It stores lubricant (for example, grease) and prevents water that leaks from the outside and enters the knob.
You can also store Das I etc. Note that the latter can also be discharged through the fluid passages 59, 69.

The dust seal of the present invention is approximately 17 characters or J7
Since it has a cross-sectional metal reinforcing ring, it can be press-fitted into the housing, and the seal lip 21 of the first seal 20 is reinforced, and the outer peripheral side portion 32 of the second seal 30 is held by the reinforcing ring. In the aspect, the second seal 3
The part 57 of the reinforcing ring is connected to the side surface 11 by the axial part 27
Fixed. These reinforcing actions reduce the deformation of each seal lip due to friction, etc., thereby maintaining good sealing performance.

Next, the specific sealing effect of the sealing device of the present invention is as follows:
It is shown in FIG.

In a test in which the rond portion of the cylinder was operated in water, the amount of water intrusion was measured for the device according to the present invention and the conventional device. The results of comparing each type of the present invention with a conventional general dust seal (Fig. 1) or a seal installation in which the dust seal and packing are installed in separate mounting grooves (Fig. 2). is shown graphically in FIG.

1 and 2 shown in FIG. 7 are conventional sealing devices. On the other hand, all of FIGS. 3 to 5 are devices according to the present invention.

As can be seen from the results shown in Fig. 7, when compared with the amount of water intrusion when operated underwater, the sealing device according to the present invention has a water intrusion amount of 175 to 1710 or less, which is a significant improvement. . The sealing device with the structure shown in Fig. 5 was the best in both long and short strokes.

[Brief explanation of the drawing]

1 and 2 are schematic cross-sectional views of a conventional sealing device; FIG. 3 is a schematic cross-sectional view of a sealing device according to the present invention; FIGS. 4 to 6 are schematic cross-sectional views of a conventional sealing device; Schematic sectional views showing various modifications of the device; and FIG. 7 are graphs showing the results of a sealing performance test of the sealing device according to the present invention and the conventional sealing device. ]: Housing 2: Rod 3: Dust seal 4: Basokin 5: Reinforcement ring 6: Dust seal Resop 7:
Oil seal lip 8: Inner lip 9: Outer lip
10: Pasokin mounting groove 20: First seal
21: Seal lip 22: Vacant space 23.
Annular protrusion 24; recess 25: reinforcing ring 26:
Radial portion 27: Axial portion 30: Second seal 31: Inner lip 32: Outer portion
33: Outer lip convex portion 34: Outer lip top 35:
Valley part 48: Jaw part 57: Crocodile part 59.69: Fluid passage 72; Oil seal lithop procedure amendment (method) % formula % 2, Name of the invention Sill device 3, Relationship with the person making the amendment case

Claims (6)

[Claims] (1) A reinforcing ring (25) that is almost entirely surrounded by an elastic material such as synthetic rubber or synthetic resin and has a substantially L-shaped or J-shaped cross section, and the inner periphery of the radial portion (26) of the reinforcing ring (25). A rod (2) provided on the side and projecting axially outward
a first sealing lip (21) that abuts the surface of the
a seal (20); and a second seal (30) made of an elastic material such as synthetic rubber or synthetic resin and having an inner lip (31) that comes into contact with the surface of the rod (2). 2
The seal (30) is attached to the reinforcing ring (2) of the first seal (20).
5) into a cavity (22) defined by an axial portion (27) and a radial portion (26), and the second seal (30)
A seal device configured such that an outer circumferential portion (32) of the first seal (20) abuts an inner circumferential surface of an axial portion (27) of the reinforcing ring (25) of the first seal (20). (2) Recesses (24) in the covered areas of the elastic material on the inner peripheral surfaces of the axial portion (27) and the radial portion (26) and convex portions (33) in the outer peripheral portion (32) of the second seal. ) or the top (34) of the outer circumference side part (32) is formed into a shape in which the concavities and convexities coincide with each other, and the outer circumference side part (34) of the second seal is
2), and the first seal (
the second seal (30) on the radial portion (26) of the
An annular convex portion (23) that protrudes toward the trough (35) between the outer circumferential portion (32) and the inner circumferential lip (31) of the second seal (30) and supports the outer circumferential portion (32) of the second seal (30). The sealing device according to claim 1, further comprising: (3) A radially extending flange (57) is provided on the outer peripheral side of the main body (50) of the second seal (30), and the flange (57)
) is configured to be fixed between the bottom surface of the axial portion (27) of the first seal (20) and the side surface (11) of the mounting groove. (4) the bottom surface of the main body (56) of the second seal (30);
One or more annular projections (58″) on the bottom surface of the flange (57) and the top surface of the flange (57), respectively;
The sealing device according to claim 3, further comprising (58') and (58). (5) A jaw portion ( 48),
The inner lip (31) is set to be shorter in the axial direction than the outer circumferential portion (32), and is installed so as to have a slight gap between it and the jaw (48) when worn.
5. The seal device according to claim 2, further comprising a plurality of fluid passages (59), (69) extending in the radial direction at the top of the inner lip (31). (6) A first seal is attached to the inner peripheral surface of the second seal (30) on the bottom side of the main body.
6. The sealing device according to claim 1, further comprising an oil seal lip (72) projecting axially opposite to the lip of the seal (20).