JP2005249033A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device, improving lubricity in a sliding part. <P>SOLUTION: The sliding surface of a first seal ring 2 is provided with a first groove 21 extended from one end in the axial direction to the midway position toward the other end and a second groove 22 extended from the other end part in the axial direction to the midway position toward one end part, and the first groove 21 and the second groove 22 are independently provided not to be connected to each other, and also the axial range for providing the first groove 21 and the axial range for providing the second groove 2 include an overlapping part S. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  Conventionally, a sealing device for sealing an annular gap between a relatively rotating shaft and a housing has been used in a swivel joint portion or the like in a construction machine or a machine tool. An example of a sealing device according to a conventional example will be described with reference to FIG. FIG. 4 is a partially broken sectional view of a conventional sealing device. As illustrated, the sealing device 100 includes a first seal ring 200 and a second seal ring 300. As for the 1st seal ring 100, the internal peripheral surface slides with respect to the rotating shaft not shown. The second seal ring 300 has an inner peripheral surface that is in close contact with the outer peripheral surface of the first seal ring 200, and an outer peripheral surface that is in close contact with an inner peripheral surface of a shaft hole of a housing (not shown).

  The sealing device 100 is required to maintain sealing performance under conditions in which the pressure of the sealing fluid (oil) acts from one side or both sides in the axial direction. In order to improve the durability of the sealing device 100 while maintaining stable sealing performance, it is necessary to form an oil film continuously between the inner peripheral surface of the first seal ring 200 and the outer peripheral surface of the rotary shaft. is there. In order to form the oil film, in the sealing device 100 according to the conventional example, an annular groove 201 extending in the rotation direction is provided on the inner peripheral surface of the first seal ring 200.

  Even in the sealing device 100 configured as described above, an oil film is always formed in a portion where the groove 201 is provided (or in the vicinity thereof), but a portion where the groove 201 is not provided is likely to cause an oil film breakage. Particularly, the oil pressure is high, and the oil film is easily cut off during continuous pressurization operation. If the operation is continued with the oil film running out, temperature rise and rotational torque increase at the sliding part. Moreover, these accelerate | stimulate wear of the 1st seal ring 200, and will also cause the fall of sealing performance.

Other related arts are disclosed in Patent Documents 1 to 5.
JP 2002-295589 A JP-A-10-213231 JP-A-9-133215 JP 2000-81146 A JP 2003-4143 A

  One of the objects of the present invention is to improve the lubricity at the sliding portion.

  Another object of the present invention is to improve durability.

  Another object of the present invention is to improve the sealing performance.

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

That is, the present invention employs a configuration in which a plurality of independent grooves are formed on the sliding surface of the resin seal ring so that an oil film can be formed on the entire sliding surface. Here, the plurality of grooves were formed so as to satisfy the following conditions. (1) There is no groove extending from one end in the axial direction to the other end on the sliding surface. (2) When the axial regions of the grooves are combined, the sliding surface reaches the entire region from one end portion in the axial direction to the other end portion. (3) The plurality of grooves are provided so that a part of an axial range in which a certain groove is provided overlaps a part of an axial range in which another groove is provided.

  If the structure of this invention is employ | adopted, if oil will penetrate into at least 1 groove | channel, oil will be transmitted to another groove | channel while forming an oil film, Therefore An oil film can be formed in the whole sliding surface. Thereby, the lubricity of a sliding part improves.

As a more specific sealing device of the present invention,
A sealing device for sealing an annular gap between two relatively rotating members,
A first seal ring made of resin that slides against one of the two members;
In a sealing device comprising: a second seal ring that is in close contact with the other member of the two members and the first seal ring, and that presses each with its own elastic repulsion force,
On the sliding surface side of the first seal ring with respect to the one member,
A first groove extending from one end in the axial direction to a middle position toward the other end;
A second groove is provided extending from the other end in the axial direction to a middle position toward the one end;
The first groove and the second groove are provided independently so as not to be connected, and the axial range where the first groove is provided and the axial range where the second groove is provided overlap each other. The thing characterized by containing is mentioned.

  According to the configuration of the present invention, neither the first groove nor the second groove extends from one end portion in the axial direction to the other end portion, and both are not connected, so that the sealing performance is deteriorated. It doesn't let you. Even if oil exists only on one side via the sealing device, the oil enters one groove to form an oil film, and is transmitted to the other groove by the “overlapping portion”. Therefore, an oil film is formed on the entire sliding surface. Thereby, the lubricity of a sliding part improves.

Moreover, as a more specific sealing device of the present invention, in addition, a sealing device for sealing an annular gap between two relatively rotating members,
A first seal ring made of resin that slides against one of the two members;
In a sealing device comprising: a second seal ring that is in close contact with the other member of the two members and the first seal ring, and that presses each with its own elastic repulsion force,
On the sliding surface side of the first seal ring with respect to the one member,
A first groove extending from one end in the axial direction to a middle position toward the other end;
A second groove extending from the other end portion in the axial direction to a middle position toward the one end portion;
A third groove is provided which does not reach one of the other ends in the axial direction;
The first groove, the second groove, and the third groove are provided independently so as not to be connected to each other, and the axial range in which the first groove is provided and the axial range in which the third groove is provided. And the axial range in which the second groove is provided and the axial range in which the third groove is provided include an overlapping portion.

  According to the configuration of the present invention, none of the first groove, the second groove, and the third groove reach from the one end in the axial direction to the other end, and these are not connected. It does not reduce the sealing performance. Even if oil is present only on one side through the sealing device, the oil enters one of the first groove or the second groove to form an oil film, and the “overlapping portion” causes the third It is transmitted to the groove. Further, the “overlapping portion” is transmitted from the third groove to the other of the first groove and the second groove. Therefore, an oil film is formed on the entire sliding surface. Thereby, the lubricity of a sliding part improves.

  The third groove may be a single groove or a plurality of third grooves. However, in the case of being composed of a plurality, it is necessary to satisfy the following conditions. (1) When the axial regions of the first groove, the second groove, and the third groove are combined, the sliding surface reaches the entire region from one end portion in the axial direction to the other end portion. (2) Among a plurality of grooves constituting the third groove, a part of an axial range in which a certain groove is provided overlaps with a part of an axial range in which another groove is provided.

  As described above, according to the present invention, the lubricity at the sliding portion is improved. Further, along with this, wear of the sealing device is suppressed, and durability is improved. These improve the sealing performance.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. 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. .

  With reference to FIG.1 and FIG.2, the sealing device which concerns on Example 1 of this invention is demonstrated. 1 is a partially broken cross-sectional view of a sealing device according to Embodiment 1 of the present invention. FIG. 2 is an external view showing various modifications of grooves provided in a resin seal ring constituting the sealing device.

<Overall configuration of sealing device>
With reference to FIG. 1, the whole structure of the sealing device based on Example 1 of this invention is demonstrated. The sealing device 1 according to the first embodiment of the present invention includes a first seal ring 2 and a second seal ring 3. As for the 1st seal ring 2, the internal peripheral surface slides with respect to the rotating shaft not shown. The material of the first seal ring 2 is a resin material such as nylon (registered trademark) or polytetrafluoroethylene (PTFE). The inner peripheral surface of the second seal ring 3 is in close contact with the outer peripheral surface of the first seal ring 2, and the outer peripheral surface thereof is in close contact with the inner peripheral surface of a shaft hole of a housing (not shown). The material of the second seal ring 3 is a material that exhibits an elastic function, such as urethane or rubber. The second seal ring 3 presses the outer peripheral surface of the first seal ring 2 and the inner peripheral surface of the shaft hole of the housing by its own elastic repulsive force. Therefore, even if the sliding surface of the first seal ring 2 is worn down over time due to wear, the inner peripheral surface of the first seal ring 2 can be stably slid with respect to the rotating shaft over a long period of time. it can. Note that the first seal ring 2 and the second seal ring 3 may not be fixed, or may be fixed by baking or the like. In FIG. 1, the second seal ring 3 is an example of a square ring, but other seal rings such as an O-ring may be used.

<Usage example of sealing device>
The sealing device 1 according to the first embodiment seals an annular gap between the outer peripheral surface of the rotary shaft and the inner peripheral surface of the shaft hole provided in the housing in a swivel joint portion or the like in a construction machine or a machine tool. It can be suitably used as the apparatus. In this case, generally, the rotation speed of a rotating shaft is 12 to 1000 rpm. In addition, the sealing device 1 according to the first embodiment is used when the pressure of the sealing fluid (oil) is applied from one side in the axial direction and when the pressure of the sealing fluid (oil) is applied from both sides in the axial direction. Even if it exists, it can be used conveniently.

<Detailed description of the first seal ring 2>
The first seal ring 2 will be described in detail. On the inner peripheral surface of the first seal ring 2, a first groove 21 and a second groove 22 are provided independently so that they are not connected to each other. First
The groove 21 is configured to extend from one end in the axial direction to a middle position toward the other end. Further, the second groove 22 is configured to extend from the other end portion in the axial direction to a middle position toward the one end portion. Then, the axial range in which the first groove 21 is provided and the axial range in which the second groove 22 is provided include an overlapping portion (range indicated by S in FIG. 1).

  Next, the conditions required for the first groove 21 and the second groove 22 will be described in a little more detail. The shape of these grooves is not particularly limited. Some examples of groove shapes are shown in FIG. 2 is an enlarged view of a portion corresponding to a portion indicated by P in FIG. That is, as the shape viewed from the center of the first seal ring 2 toward the inner peripheral surface, an appropriate shape other than a triangle, a quadrangle, a semicircle, or a combination thereof can be adopted. As for the shape of the first seal ring 2 viewed from the end face side in the axial direction, an appropriate shape can be employed in addition to a triangle, a quadrangle, a semicircle, or a combination thereof. Moreover, about both, it can combine suitably.

  Further, the maximum depth T of these grooves satisfies T <T1 when the thickness T1 of the first seal ring 2 is satisfied. Further, the interval L between the first groove 21 and the second groove 22 satisfies L> 0 mm unless the shape of these grooves is a special shape (a shape having a portion refracted in the circumferential direction). The number of first grooves 21 and second grooves 22 is 1 or more, respectively. The overlapping portion S satisfies H> S> 0 mm when the axial length H of the first seal ring 2 is set.

<Effects obtained by the first groove 21 and the second groove 22>
(1) When oil exists on both sides in the axial direction of the sealing device 1 to prevent mutual leakage.

  In this case, the oil enters the grooves from the end portions of the first groove 21 and the second groove 22. Therefore, since the oil film is formed at each position, it goes without saying that the oil film is formed on the entire sliding surface of the first seal ring 2 with respect to the rotation shaft.

  (2) The case where oil exists only on one side of the sealing device 1 in the axial direction and prevents oil leakage to the other side. In addition, since the same effect is exhibited regardless of which oil is present on the side, here, a case where oil is present on the first groove 21 side will be described as an example.

  In this case, oil enters the first groove 21. Then, by sliding between the first seal ring 2 and the rotating shaft, an oil film is formed in the entire circumferential direction at least in the axial range where the first groove 21 is provided. Since the “overlapping portion S” is provided as described above, a part of the second groove 22 always passes through the portion where the oil film is formed (overlapping portion S). At this time, since the opening end (the edge) on the sliding surface side of the second groove 22 scrapes off a part of the oil film, the oil also enters the second groove 22. Thereby, an oil film is formed in the whole circumferential direction also in the axial direction range in which the second groove 22 is provided. Eventually, an oil film is formed on the entire sliding surface between the first seal ring 2 and the rotating shaft.

  Here, since the movement of the oil from the first groove 21 to the second groove 22 is performed by scraping the oil film, only a small amount of oil can be supplied to the second groove 22. Therefore, it is possible to suppress oil from leaking more than necessary. In addition, since an appropriate amount of oil can be constantly fed, an oil film can be stably formed. Note that the amount of oil fed from the first groove 21 to the second groove 22 includes the side wall surface of each groove and the inner peripheral surface of the first seal ring 2 (that is, the sliding surface (the surface on which no groove is provided)). It can be adjusted by the angle between That is, the thickness of the oil film to be formed and the scraping amount of the oil film can be adjusted by these angles.

  As described above, according to the sealing device 1 according to the first embodiment, the oil film can be stably formed on the entire sliding surface between the first seal ring 2 and the rotating shaft. For example, even if continuous pressurization operation continues for a long time (and when high pressure conditions are applied), a small amount of oil can be continuously fed, so an oil film is always formed. Can do. Accordingly, the lubricity of the sliding portion is improved. Thereby, the temperature rise of a sliding part and the raise of a rotational torque can be suppressed. Further, along with these, wear of the first seal ring 2 can be suppressed. Therefore, the durability of the first seal ring 2 and thus the sealing device 1 is improved. Further, along with these, stable sealing performance can be maintained, and sealing performance is improved. In addition, since the groove | channel formed in the 1st seal ring 2 may be a simple shape as above-mentioned, manufacture is also easy.

<Example of specific evaluation>
A comparative evaluation was performed between the sealing device according to Example 1 shown in FIG. 1 and the sealing device in which the grooves (the first groove 21 and the second groove 22) were removed from the sealing device. The evaluation conditions were (1) 25 MPa hydraulic pressure and continuous pressurization operation (2) Rotating shaft rotation speed was 15 rpm (3) No environmental temperature adjustment (natural rise) (4) Oil was Daphne 46 (trade name) is there.

  As a result of this evaluation, in the case of the sealing device according to the comparative example (no groove), the rotational torque exceeded 60 N · m, which was doubled after 20 minutes from the initial value of 30 N · m. On the other hand, in the case of the sealing device 1 according to Example 1, the rotational torque was stabilized at about 32 N · m and did not increase any more. In addition, the temperature of the sliding portion was high in the case of the comparative example, and the temperature rose even when the temperature exceeded 100 ° C. On the other hand, in the case of the sealing device 1 according to Example 1, the temperature increase rate was low, and the temperature did not increase at about 100 ° C.

  With reference to FIG. 3, the sealing apparatus which concerns on Example 2 of this invention is demonstrated. FIG. 3 is a partially broken sectional view of a sealing device according to Embodiment 2 of the present invention. In the present embodiment, only the structure of the groove provided on the inner peripheral surface of the first seal ring is different from the structure of the first embodiment. Since the other basic configuration is the same as that of the first embodiment, the description thereof will be omitted as appropriate.

  The sealing device 1a according to the present embodiment is also composed of a first seal ring 2a and a second seal ring 3. And the 1st groove | channel 21a, the 2nd groove | channel 22a, and the 3rd groove | channel 23a are independently provided in the internal peripheral surface of the 1st seal ring 2a so that it may not connect, respectively. The first groove 21a is configured to extend from one end portion in the axial direction to a middle position toward the other end portion. Further, the second groove 22a is configured to extend from the other end portion in the axial direction to a middle position toward the one end portion. And the 3rd groove | channel 23a is the structure provided in the center so that it may not reach any of the both ends of an axial direction.

  Here, unlike the first embodiment, there is no overlapping portion in the axial range in which the first groove 21a is provided and the axial range in which the second groove 22a is provided. However, the axial range in which the first groove 21a is provided and the axial range in which the third groove 23a is provided, and the axial range in which the second groove 22a is provided and the third groove 23a are provided. The overlapping ranges (ranges indicated by T in FIG. 1) are included in the ranges in the axial direction. Accordingly, an oil film is formed on the entire sliding surface between the first seal ring 2a and the rotating shaft. The reason is the same as that described in the first embodiment, and a description thereof will be omitted. Thereby, the effect similar to the said Example 1 can be acquired.

1 is a partially broken cross-sectional view of a sealing device according to Embodiment 1 of the present invention. FIG. 2 is an external view showing various modifications of grooves provided in a resin seal ring constituting the sealing device. FIG. 3 is a partially broken sectional view of a sealing device according to Embodiment 2 of the present invention. FIG. 4 is a partially broken sectional view of a conventional sealing device.

Explanation of symbols

1, 1a Sealing device 2, 2a First seal ring 21, 21a First groove 22, 22a Second groove 23a Third groove 3 Second seal ring

Claims (2)

A sealing device for sealing an annular gap between two relatively rotating members,
A first seal ring made of resin that slides against one of the two members;
In a sealing device comprising: a second seal ring that is in close contact with the other member of the two members and the first seal ring, and that presses each with its own elastic repulsion force,
On the sliding surface side of the first seal ring with respect to the one member,
A first groove extending from one end in the axial direction to a middle position toward the other end;
A second groove is provided extending from the other end in the axial direction to a middle position toward the one end;
The first groove and the second groove are provided independently so as not to be connected, and the axial range where the first groove is provided and the axial range where the second groove is provided overlap each other. The sealing device characterized by including. A sealing device for sealing an annular gap between two relatively rotating members,
A first seal ring made of resin that slides against one of the two members;
In a sealing device comprising: a second seal ring that is in close contact with the other member of the two members and the first seal ring, and that presses each with its own elastic repulsion force,
On the sliding surface side of the first seal ring with respect to the one member,
A first groove extending from one end in the axial direction to a middle position toward the other end;
A second groove extending from the other end portion in the axial direction to a middle position toward the one end portion;
A third groove is provided which does not reach one of the other ends in the axial direction;
The first groove, the second groove, and the third groove are provided independently so as not to be connected to each other, and the axial range in which the first groove is provided and the axial range in which the third groove is provided. And the axial range in which the second groove is provided and the axial range in which the third groove is provided include overlapping portions.

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