JP2010196763A - Sealing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing system for improving abrasion resistance in a simple constitution. <P>SOLUTION: This sealing system includes a first sealing device 10 installed in a first annular groove 301 arranged in a housing 300, and a second sealing deice 20 arranged in the housing 300 and installed in a second annular groove 302 arranged on the sealing side (W) further than the first annular groove 301, and is characterized in that the second sealing device 20 is slidingly arranged to a rod 200, and is arranged so as to be movable in the reciprocating direction in the second annular groove 302 and to have the clearance between the groove bottom and itself. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealing system that seals an annular gap between two members that reciprocate relatively.

  A plunger pump or a hydraulic cylinder is provided with a sealing device for sealing an annular gap between two members that reciprocally move relative to each other. Here, when the fluid to be sealed (hereinafter referred to as a sealed fluid) is a material having a lower viscosity than oil such as water or agricultural chemicals, the lubrication state is poor. Therefore, as a sealing device, a seal using a material having excellent wear resistance (such as PTFE) or a V-packing (see Patent Document 1) that can secure a tightening margin even when a sliding part is worn is used. Yes.

  As an example, the former case will be described with reference to FIG. FIG. 7 is a schematic cross-sectional view of a sealing device according to Conventional Example 1. In the drawing, the right side is the sealing side (W), and the left side is the side opposite to the sealing side (hereinafter referred to as the anti-sealing side) (A).

  The sealing device 500 is used to seal an annular gap between the rod 200 and the housing 300 that reciprocate relatively. The sealing device 500 is mounted in an annular groove 301 provided in the housing 300 and provided in the inner peripheral surface of the shaft hole through which the rod 200 is inserted. The sealing device 500 includes a resin ring 520 made of PTFE having excellent wear resistance and a rubber ring 510 for pressing the resin ring 520 against the outer peripheral surface of the rod 200.

  In the sealing device 500 configured as described above, the rod 200 and the housing 300 slide between the rod 200 and the resin ring 520 when they relatively reciprocate. As described above, since the resin ring 520 is made of PTFE having excellent wear resistance, the resin ring 520 is excellent in durability as compared with the case of sealing with a rubber seal.

  However, as described above, when the sealing fluid has a low viscosity, the lubrication state is still bad, and the product life is short, so there is a need for longer life. In response to the need for a longer life, there are also known ones in which a plurality of sealing devices are arranged. Such a sealing structure according to Conventional Example 2 will be described with reference to FIG. In the figure, the right side is the sealing side (W) and the left side is the anti-sealing side (A). FIG. 8 is a schematic cross-sectional view of a sealing structure according to Conventional Example 2.

  As shown in the figure, in this conventional example, two annular grooves 301 are provided on the inner peripheral surface of the shaft hole of the housing 300. A sealing device 500 is attached to each of the two annular grooves 301. Since the configuration of each sealing device 500 is the same as the configuration of the conventional example 1, the description thereof will be omitted.

  In the case of this conventional example, a large load is applied to the sealing device 500 on the sealing side (W) that becomes high in the early stage, and at first, the sealing device 500 on the sealing side (W) deteriorates due to wear. When the pressure resistance of the sealing device 500 on the sealing side (W) is lost, a load is applied to the sealing device 500 on the anti-sealing side (A). Accordingly, in the case of this conventional example, the product life is approximately doubled as compared with the case where there is only one sealing device 500.

  However, such measures are less effective because the product life is only increased by the increase in the number of sealing devices.

  Here, in the reciprocating sealing device, when the sealing fluid is oil, an oil film is formed on the surface of the rod when the sealing device moves relative to the rod toward the sealing side. And when a sealing device moves relatively to the anti-sealing side with respect to a rod, the lubricity of a sliding part is maintained by the oil film formed in the surface of a rod. However, in the case where the sealing fluid has a low viscosity, such as agricultural chemicals or water, when the sealing device moves relative to the sealing side relative to the rod, no fluid film is formed on the surface of the rod. Accordingly, when the sealing device moves relative to the anti-sealing side with respect to the rod, sliding resistance increases and wear is promoted.

  In view of this, it is also known that a lubricant (generally a sealing fluid) is forcibly supplied to the sliding portion of the sealing device also from the anti-sealing side. Such a sealing structure according to Conventional Example 3 will be described with reference to FIG. In the figure, the left side is the sealing side (W) and the right side is the anti-sealing side (A). FIG. 9 is a schematic cross-sectional view of a sealing structure according to Conventional Example 3.

  Also in this conventional example, two annular grooves 301 are provided on the inner peripheral surface of the shaft hole of the housing 300. A sealing device 500 is attached to each of the two annular grooves 301. Since the configuration of each sealing device 500 is the same as the configuration of the conventional example 1, the description thereof will be omitted.

  In the case of this conventional example, a communication hole that communicates with the annular gap between the rod 200 and the housing 300 is provided between the two annular grooves 301, and the lubricant (usually sealed) is communicated through this communication hole. A supply mechanism 600 for supplying a fluid is provided. The supply mechanism 600 is configured by, for example, a pump or a drain port.

  In the case of this conventional example, since the sealing fluid is supplied from the anti-sealing side (A) to the sealing device 500 on the sealing side (W) by the supply mechanism 600, the lubricity of the sliding portion is maintained. Sagging and wear resistance can be improved.

  However, in the case of this conventional example 3, since the supply mechanism 600 is required, there is a drawback that the structure becomes complicated.

Japanese Utility Model Publication No. 60-82588 JP 2001-41323 A

  An object of the present invention is to provide a sealing system that improves the wear resistance with a simple structure.

  The present invention employs the following means in order to solve the above problems.

That is, the sealing system of the present invention is
In a sealing system for sealing an annular gap between two members that reciprocate relatively,
A first sealing device mounted in a first annular groove provided in one of the two members;
A second sealing device mounted on the second annular groove provided on the one member and provided on the sealing side of the first annular groove;
With
The second sealing device is
The second member is slidably provided with respect to the other member,
In the second annular groove, the second annular groove is arranged so as to be movable in the reciprocating direction and to have a gap with the groove bottom.

  According to the present invention, the second sealing device is configured to be movable in the reciprocating direction in the second annular groove, and is disposed so as to have a gap with the groove bottom. Therefore, when the pressure of the fluid to be sealed (hereinafter referred to as the sealing fluid) is not applied, the second sealing device is on the side opposite to the sealing side in the second annular groove (hereinafter referred to as the anti-sealing side). Apart from the side surface, the sealing fluid is supplied to the anti-sealing side rather than the second sealing device.

  Accordingly, the sealing fluid can be present on both sides of the sealing side and the anti-sealing side via the second sealing device, and the lubricity of the sliding portion between the second sealing device and the other member can be maintained.

  Moreover, it is good for the surface which slides with respect to the other member in a 2nd sealing device to form the groove | channel connected only to one of both end surfaces. The term “groove communicating only with one of both end faces” as used herein means a groove communicating only with the end face on the sealing side or a groove communicating only with the end face on the anti-sealing side. And in this invention, what is equipped with these both groove | channels is also included.

  Thus, by forming the groove as described above on the sliding surface, the sealing fluid can be actively guided to the sliding surface. Thereby, the lubricity of the sliding part of a 2nd sealing device and the other member can be maintained.

On the side opposite to the sealing side in the second annular groove, an inclined surface is provided in which the distance from the other member becomes shorter from the sealing side toward the opposite side,
The second sealing device may be formed of a single annular member, and may be provided with a close contact surface that comes into close contact with the inclined surface as the second sealing device moves to the side opposite to the sealing side.

  If comprised in this way, the 2nd sealing device will move to the anti-sealing side with the pressure of the sealing fluid, and the contact surface provided in the 2nd sealing device will contact | adhere to the inclined surface provided in the 2nd annular groove To do.

  Therefore, even if the thickness of the second sealing device is reduced due to sliding wear, the sealing performance (pressure resistance performance) by the second sealing device is maintained, so that the sealing performance of the sealing system can be maintained over a long period of time. .

  In addition, said each structure can be employ | adopted combining as much as possible.

  As described above, according to the present invention, it is possible to improve wear resistance with a simple configuration.

FIG. 1 is a schematic cross-sectional view of a sealing system according to Embodiment 1 of the present invention. FIG. 2 is a schematic cross-sectional view showing a usage state of the sealing system according to the first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a usage state of the sealing system according to the first embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a second sealing device according to Embodiment 2 of the present invention. FIG. 5 is a schematic cross-sectional view showing a usage state of the second sealing device according to the third embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing a usage state of the second sealing device according to Embodiment 3 of the present invention. FIG. 7 is a schematic cross-sectional view of a sealing device according to Conventional Example 1. FIG. 8 is a schematic cross-sectional view of a sealing structure according to Conventional Example 2. FIG. 9 is a schematic cross-sectional view of a sealing structure according to Conventional Example 3.

  EMBODIMENT OF THE INVENTION Below, with reference to drawings, the form for implementing this invention is demonstrated in detail exemplarily based on an Example. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

Example 1
With reference to FIGS. 1-3, the sealing system which concerns on Example 1 of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view of a sealing system according to Embodiment 1 of the present invention. 2 and 3 are schematic cross-sectional views showing a usage state of the sealing system according to the first embodiment of the present invention. 2 shows a state where there is a load due to the pressure of a fluid to be sealed (hereinafter referred to as a sealing fluid), and FIG. 3 shows a state where there is no load due to the pressure of the sealing fluid. 2 and 3, the right side is the sealing side (W), and the left side is the side opposite to the sealing side (hereinafter referred to as the anti-sealing side) (A).

<Configuration of sealing system>
The sealing system 100 according to the first embodiment of the present invention is applied to a plunger pump and a hydraulic cylinder. More specifically, the sealing system 100 is used to seal an annular gap between the relatively reciprocating rod 200 and the housing 300. The sealing system 100 includes a first sealing device 10 and a second sealing device 20.

  The first sealing device 10 is attached to a first annular groove 301 provided on the inner peripheral surface of the shaft hole of the housing 300. The second sealing device 20 is mounted on a second annular groove 302 provided on the inner peripheral surface of the shaft hole of the housing 300 and provided on the sealing side (W) with respect to the first annular groove 301.

  Here, the first sealing device 10 includes a resin ring 12 made of a resin such as PTFE having excellent wear resistance, and a rubber ring 11. The inner peripheral surface of the resin ring 12 is mounted so as to be slidable with respect to the outer peripheral surface of the rod 200. The rubber ring 11 is mounted in a compressed state by the outer peripheral surface of the resin ring 12 and the groove bottom (inner peripheral surface) of the first annular groove 301. Thereby, the inner peripheral surface of the resin ring 12 is pressed against the outer peripheral surface of the rod 200 by the repulsive force of the rubber ring 11.

  The second sealing device 20 is configured by a single annular member. As a material of the second sealing device 20, a resin such as PTFE having excellent wear resistance can be suitably used.

  The second sealing device 20 is mounted in the second annular groove 302 with its inner peripheral surface slidable with respect to the outer peripheral surface of the rod 200 (in FIG. 2, S1 indicates a sliding portion). ) The second sealing device 20 is arranged so as to be movable in the reciprocating direction in the second annular groove 302 and to have a gap between the second annular groove 302 and the groove bottom. Moreover, the 2nd sealing apparatus 20 which concerns on a present Example is provided with the chamfer 21 in the inner peripheral side and the anti-sealing side (A).

<Operation of sealing system>
FIG. 2 shows a state where there is a load due to the pressure of the sealing fluid. In this case, due to the pressure of the sealing fluid, the second sealing device 20 is in close contact with the side wall surface of the second annular groove 302 on the side opposite to the sealing side (A) (in FIG. 2, S2 indicates a close contact portion). Accordingly, the fluid path from the sealing side (W) to the first sealing device 10 is blocked by the second sealing device 20. Therefore, when the second sealing device 20 receives the pressure of the sealing fluid, it is possible to prevent the fluid pressure load from being applied to the first sealing device 10. In this embodiment, since the chamfer 21 is provided on the inner peripheral side and the anti-sealing side (A) of the second sealing device 20, the inner peripheral side and the anti-sealing side (A) of the second sealing device 20 are provided. It is possible to prevent the end edge portion from protruding into the gap between the inner peripheral surface of the shaft hole of the housing 300 (the portion where the annular groove is not formed) and the outer peripheral surface of the rod 200. Thereby, the damage of this part can be suppressed.

  FIG. 3 shows a state where there is no load due to the pressure of the sealing fluid. In this case, the 2nd sealing device 20 will be in the state away from this side wall surface after the adhesion state to the side wall surface of the 2nd annular groove 302 on the anti-sealing side (A) is canceled. Thus, the sealing side (via the clearance between the second sealing device 20 and the groove bottom of the second annular groove 302 and the clearance between the second sealing device 20 and the side wall surface of the second annular groove 302). A fluid path from W) to the first sealing device 10 is formed. Therefore, the sealing fluid is supplied to the anti-sealing side (A) from the second sealing device 20.

<Excellent points of this embodiment>
As described above, according to the sealing system 100 according to the present embodiment, when the pressure of the sealing fluid is not applied, the second sealing device 20 is separated from the side surface on the anti-sealing side (A) in the second annular groove 302. Thus, the sealing fluid is supplied to the anti-sealing side (A) from the second sealing device 20.

  Thereby, the sealing fluid can be present on both sides of the sealing side (W) and the anti-sealing side (A) via the second sealing device 20, and lubrication of the sliding portion between the second sealing device 20 and the rod 200 is possible. Can keep sex. Therefore, even if the sealing fluid has a lower viscosity than oil, such as water and agricultural chemicals, the presence of the sealing fluid on both sides of the second sealing device 20 can maintain the lubricity of the sliding portion. it can.

  Thus, according to the sealing system 100 according to the present embodiment, it is possible to maintain a good lubrication state with a simple configuration as compared with the case where a supply mechanism for supplying the lubricant is provided. Further, along with this, the wear resistance can be improved, and the product life can be extended.

  For example, when the sealing system 100 according to the present embodiment is applied to a plunger pump, the state shown in FIG. 2 when the rod 200 moves relative to the housing 300 to the anti-sealing side (A). Thus, when the rod 200 moves relative to the housing 300 toward the sealing side (W), the state shown in FIG. Therefore, when the rod 200 and the housing 300 relatively reciprocate, the sealing fluid always exists on both sides of the second sealing device 20.

(Example 2)
FIG. 4 shows a second embodiment of the present invention. In a present Example, the structure in the case of providing a groove | channel in the surface which slides with respect to the rod in a 2nd sealing device is shown. Since other basic configurations and operations are the same as those in the first embodiment, the description of the same components will be omitted.

FIG. 4 is a schematic cross-sectional view of a second sealing device according to Embodiment 2 of the present invention. The second sealing device 30 according to the present embodiment is also configured by a single annular member, as in the case of the second sealing device 20 according to the first embodiment. In addition, the inner circumferential surface of the rod 200 is slidable with respect to the outer circumferential surface of the rod 200. The second annular groove 302 is attached to the inner circumferential surface. It is the same as that of the said Example 1 also about the point arrange | positioned so that it may have a clearance gap between the groove bottoms of the groove | channel 302. FIG. Furthermore, also in the 2nd sealing device 30 which concerns on a present Example, the chamfer 31 is provided in the inner peripheral side and the anti-sealing side (A).

  The second sealing device 30 according to the present embodiment is different from the second sealing device 20 according to the first embodiment in that a plurality of grooves 32 are formed on the inner peripheral surface (surface that slides with respect to the rod 200). 33 is provided. In this embodiment, a groove 32 communicating only with the sealing side (W) and a groove 33 communicating only with the anti-sealing side (A) are provided. A plurality of the grooves 32 and 33 are provided at predetermined intervals in the circumferential direction.

  As described above, according to the second sealing device 30 according to the present embodiment, since the grooves 32 and 33 are provided on the inner peripheral surface serving as the sliding surface, the sealing fluid is positively guided to the sliding surface. be able to. Thereby, the lubricity of the sliding part of the 2nd sealing device 30 and the rod 200 can be kept still more suitable.

(Example 3)
5 and 6 show Embodiment 3 of the present invention. In a present Example, the structure at the time of providing the taper (inclined surface) for exhibiting a self-sealing function in a 2nd sealing device is shown. Since other basic configurations and operations are the same as those in the first embodiment, the description of the same components will be omitted.

  5 and 6 are schematic cross-sectional views showing a usage state of the second sealing device according to Embodiment 3 of the present invention. 5 shows a state where there is a load due to the pressure of the fluid to be sealed, and FIG. 6 shows a state where there is no load due to the pressure of the sealing fluid. 5 and 6, the right side is the sealing side (W) and the left side is the anti-sealing side (A).

  The second sealing device 40 according to the present embodiment is also configured by a single annular member, as in the case of the second sealing device 20 according to the first embodiment. Further, the inner peripheral surface of the rod 200 is slidable with respect to the outer peripheral surface of the rod 200, and is mounted in the second annular groove 303. The second annular groove 303 is movable in the reciprocating direction, and the second annular groove. It is the same as that of the said Example 1 also about the point arrange | positioned so that it may have a clearance gap between the groove bottoms of the groove | channel 303. FIG.

  In this embodiment, the anti-sealing side (A) of the second annular groove 303 is inclined so that the distance from the rod 200 becomes shorter as it goes from the sealing side (W) to the anti-sealing side (A). A surface 303a is provided. More specifically, the inclined surface 303a is constituted by a tapered surface that decreases in diameter as it goes from the sealing side (W) to the anti-sealing side (A).

  Moreover, the taper surface 41 which is diameter-reduced as it goes to the anti-sealing side (A) from the sealing side (W) is provided in the anti-sealing side (A) in the 2nd sealing device 40. As shown in FIG.

  In this embodiment, when there is a load due to the pressure of the sealing fluid, as shown in FIG. 5, the second sealing device 40 moves to the anti-sealing side (A), and the tapered surface 41 in the second sealing device 40. Closely contacts the inclined surface 303a of the second annular groove 303. That is, the taper surface 41 in the second sealing device 40 constitutes a close contact surface.

Further, when there is no load due to the pressure of the sealing fluid, as shown in FIG. 6, the second sealing device 40 eliminates the contact state of the tapered surface 41 with the inclined surface 303a in the second annular groove 303, It will be in the state away from this inclined surface 303a. Accordingly, the gaps between the second sealing device 40 and the groove bottom of the second annular groove 303, and the gaps between the second sealing device 40 and the inclined surface 303a of the second annular groove 303, respectively. As in the case of the embodiment, a fluid path from the sealing side (W) to the first sealing device 10 is formed.

  Therefore, also in the case of the present embodiment, the same operational effects as in the case of the first embodiment can be obtained. In the case of the present embodiment, the second sealing device 40 moves to the anti-sealing side by the pressure of the sealing fluid, so that the tapered surface 41 provided in the second sealing device 40 is formed in the second annular groove 303. It is in close contact with the provided inclined surface 303a. Thereby, the taper surface 41 in the 2nd sealing device 40 receives the force which goes to an inner peripheral side, and the adhesiveness of the inner peripheral surface of the 2nd sealing device 40 and the rod 200 increases. A so-called self-sealing function is exhibited. Therefore, even if the thickness of the second sealing device 40 is reduced due to sliding wear, the sealing performance (pressure resistance performance) of the second sealing device 40 is maintained, so that the sealing performance of the sealing system can be maintained for a long time. Can do.

  In addition, in the present Example, the case where the inclined surface 303a provided in the 2nd annular groove 303 was comprised by the taper surface, and the contact | adherence surface with respect to the inclined surface 303a in the 2nd sealing device 40 was comprised by the taper surface was demonstrated. However, these inclined surfaces are not limited to tapered surfaces, and may be configured as curved surfaces.

(Other)
In each of the above-described embodiments, the case where the first sealing device and the second sealing device are mounted in the annular groove provided on the inner peripheral surface of the shaft hole of the housing has been described as an example. However, the present invention can also be applied to the case where the first sealing device and the second sealing device are mounted in an annular groove provided on the rod side.

100 sealing system 10 first sealing device 11 rubber ring 12 resin ring 20, 30, 40 second sealing device 32, 33 groove 41 taper surface 200 rod 300 housing 301 first annular groove 302, 303 second annular groove 303a inclined surface

Claims (3)

In a sealing system for sealing an annular gap between two members that reciprocate relatively,
A first sealing device mounted in a first annular groove provided in one of the two members;
A second sealing device mounted on the second annular groove provided on the one member and provided on the sealing side of the first annular groove;
With
The second sealing device is
The second member is slidably provided with respect to the other member,
A sealing system characterized by being arranged in the second annular groove so as to be movable in the reciprocating direction and having a gap with the groove bottom.   The sealing system according to claim 1, wherein a groove that communicates with only one of both end faces is formed on a surface that slides with respect to the other member of the second sealing device. On the side opposite to the sealing side in the second annular groove, an inclined surface is provided in which the distance from the other member becomes shorter from the sealing side toward the opposite side,
The second sealing device is constituted by a single annular member, and is provided with a close contact surface that comes into close contact with the inclined surface by moving the second sealing device to the side opposite to the sealing side. The sealing system according to claim 1 or 2.

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