JP2014088912A - Seal unit for reciprocation motion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal unit for reciprocation motion having such a shape as one in which a packing is hardly contacted with its entire surface by improving a volumetric absorptivity even if an inner pressure is increased and capable of realizing a superior sealing characteristic.SOLUTION: The present invention relates to a seal unit for sealing between two members by a method in which a packing is installed in an installing groove formed at one member of the two members performing a relative reciprocating motion, and the packing is comprised of an annular base part, a stationary lip and a sliding lip. The annular base part has such a shape as one in which a sectional shape of a heel part ranging from a peripheral surface opposing against the other member to its end surface of arcuate or tapered one and the annular base part does not excluded out of the extended line of the peripheral surface of the sliding lip under its free state to the other member. The end surface of the annular base part is provided with a flat part of axial perpendicular flat surface, and its flat part is provided with a peripheral continuous or non-continuous protrusion.

Description

  The present invention relates to a sealing device according to a sealing technique, and more particularly to a reciprocating sealing device. The sealing device of the present invention is used for, for example, an automobile damper mechanism or other damper mechanisms.

  Conventionally, a damper mechanism 51 shown in FIG. 6 is known, and a sealing device 61 is incorporated in the damper mechanism 51 in order to seal the oil O enclosed therein.

  The damper mechanism 51 shown in the figure is a combination of a damper shaft 52 having a piston 53 with an orifice 54 at the tip and a damper case 55 elastically supported by a spring means 56. A sealing device 61 is incorporated between the damper shaft 52 and the damper case 55 in order to seal the oil O enclosed in the cylinder. Further, a seal 71 made of an O-ring or a gasket or the like is separately attached to the split portion of the damper case 55 to seal the split portion.

  The sealing device 61 incorporated between the damper shaft 52 and the damper case 55 includes a packing 62 mounted in an annular mounting groove 57 provided on the outer peripheral surface of the damper shaft 52. As shown in an enlarged view in FIG. 62 includes an annular base 63, a stationary lip 64 that is in close contact with the bottom surface of the mounting groove 57, and a sliding lip 65 that is slidably in close contact with the inner peripheral surface of the cylindrical portion of the damper case 55. Yes.

However, the following problems are pointed out in the above prior art.
(1) When the oil is sealed (damper assembly), the volume of the oil 71 tends to be reduced due to the collapse of the seal 71 by the damper case 55. However, since the oil is an incompressible fluid, it is absorbed by the deformation of the packing 62. .
(2) The amount that cannot be absorbed by the deformation of the packing 62 increases the internal pressure.
(3) As the structure of the packing 62, the annular base portion 63 is formed such that the heel portion 63a has a cross-sectional shape at the corner end, and the annular base portion 63 extends from the extended line 65c of the outer peripheral surface 65b of the sliding side lip 65 in the free state. The damper case 55 has a shape that protrudes toward the outer periphery (the left side in the figure).
(4) According to the packing 62 having the above-described configuration, the packing 62 slides in a state of full contact due to an increase in internal pressure. Here, the entire surface contact means that the packing 62 contacts the damper case 55 over the entire surface from the lip end 65 a of the sliding side lip 65 to the heel portion 63 a of the annular base 63.
(5) Due to the events and configurations of (1) to (4) above, a large amount of oil leakage may occur when high-frequency vibration is input and high-viscosity oil is used.
(6) It is known that the internal pressure rises even during general vibrations, and it is highly possible that the rise in internal pressure at that time also affects the leakage.

  In addition, as a prior art to the present invention, there is an invention disclosed in the following Patent Document 1, which includes an “annular seal groove portion that receives fluid pressure, and an annular slide that is pressed against the sliding member by the fluid pressure”. A side lip, an annular heel portion facing the opening end side of the mounting groove, an annular shoulder portion facing the corner side of the mounting groove, and an annular fixed side pressed against the bottom surface of the mounting groove by fluid pressure In the fluid pressure packing having a lip, an annular first inclined surface that is inclined so as to gradually move away from the sliding member from the tip of the sliding side lip to the heel portion in a free state where fluid pressure does not act, The fluid pressure packing according to the present invention is characterized in that the heel portion is continuously curved from the first inclined surface.

Therefore, the difference between this prior invention and the present invention is as follows.
(A) In the prior invention, deformation starts from the lip, which is disadvantageous for maintaining the wedge shape. On the other hand, in the present invention, since there is a margin for crushing the protrusion, the lip shape can be maintained even after the initial internal pressure is absorbed.
(B) In the present invention, the protrusion is easily deformed only by the sliding lip, so that the stationary lip is hardly deformed and the stability of the seal is improved.
(C) In the present invention, since the volume of the non-sealed region is increased by the protrusion, the allowable amount of volume change is increased. Therefore, it can withstand the internal pressure rise (volume increase) during use.

Japanese Patent Laid-Open No. 2002-122241

  In view of the above, the present invention has a shape or structure in which the packing is difficult to come into contact with the entire surface even when the internal pressure is increased by improving the volume absorbability, so that it can exhibit excellent sealing performance. An object is to provide a sealing device.

  In order to achieve the above object, a reciprocating sealing device according to claim 1 of the present invention is configured such that a packing is mounted in a mounting groove provided in one of two members that reciprocate relatively, and the packing is mounted on the other. A reciprocating sealing device that seals between the two members by slidably contacting a member, wherein the packing includes an annular base, a stationary lip in close contact with the groove bottom surface of the mounting groove, and the other In the reciprocating sealing device integrally including a sliding side lip that is slidably in close contact with a member, the annular base portion has a circular cross-sectional shape of a heel portion from a peripheral surface to an end surface facing the other member. The circular base portion has a shape that does not protrude from the extension line of the peripheral surface of the sliding lip in the free state to the other member side as an arc shape, and the end surface of the annular base portion includes a flat portion perpendicular to the axis, Said Characterized in that a circumferentially continuous or discontinuous projections in Tsu isolation portion.

  Further, in the reciprocating sealing device according to claim 2 of the present invention, the packing is mounted in the mounting groove provided in one of the two members relatively reciprocating, and the packing can slide on the other member. A reciprocating sealing device that seals between the two members by being in close contact with each other, wherein the packing is slidable on the annular base, the stationary lip in close contact with the groove bottom surface of the mounting groove, and the other member In the reciprocating sealing device integrally including a sliding side lip that is in close contact with the annular base portion, the annular base portion has a tapered cross-sectional shape of the heel portion from the circumferential surface facing the other member to the end surface. Has a shape that does not protrude from the extended line of the peripheral surface of the sliding lip in the free state to the other member side, the end surface of the annular base portion includes a flat portion that is a plane perpendicular to the axis, and the flat portion has a circular shape. Zhoujo Characterized in that a connection or discontinuous projections.

  The reciprocating sealing device according to claim 3 of the present invention is the reciprocating sealing device according to claim 1 or 2, wherein when the packing is mounted in the mounting groove and in close contact with the other member, A wedge-shaped space region surrounded by the groove side surface of the mounting groove, the protrusion and annular base of the packing, and the other member is formed.

  In the sealing device of the present invention having the above-described configuration, the annular base portion has a heel portion in the basic configuration in which the packing attached to the mounting groove integrally includes the annular base portion, the stationary side lip, and the sliding side lip. In contrast, the volume of the heel portion from the circumferential surface facing the other member to the end surface is arcuate or tapered so that the annular base portion is slid in a free state. In order to have a shape that does not protrude from the extended line of the peripheral surface of the moving lip to the other member side, a relatively large space region is formed on the other member side of the annular base, and the deformation of the packing is performed here. There is room for absorption. In addition to this, in the sealing device according to the present invention, since the circumferentially continuous or discontinuous protrusion is provided on the flat portion of the end surface of the annular base portion, there is a spatial region for the height of the protrusion. This also creates room for absorbing the deformation of the packing. Therefore, when the packing is mounted in the mounting groove, the space area formed in the mounting groove is large, and this facilitates the absorption of deformation of the packing and improves the volume absorbability. Therefore, the packing makes full contact with the other member. It is possible to suppress this.

  In addition, since a projection part has moderate deformation resistance, it does not deform | transform too much at low pressure, and volume absorbability improves markedly. Further, since the flat portion of the planar shape perpendicular to the axis is provided on the end surface of the annular base portion, when the protrusion is crushed by the internal pressure, the packing stably contacts the side surface of the groove with this flat portion.

  Further, according to the above configuration of the present invention, when the packing is mounted in the mounting groove and in close contact with the other member, the groove side surface of the mounting groove, the protruding portion and the annular base of the packing, and the wedge-shaped shape surrounded by the other member Since the space region is formed, the oil (oil film) can be easily returned to the high pressure side by the wedge action or the wedge effect exhibited by the space region.

  The present invention has the following effects.

  That is, in the present invention, as described above, the annular base portion of the packing has the cross-sectional shape of the heel portion formed in an arc shape or a taper shape, and the annular base portion is in the other state from the extended line of the peripheral surface of the sliding lip in the free state. By providing a shape that does not protrude to the side and providing a circumferentially continuous or discontinuous protrusion on the flat portion of the end surface of the annular base, it is relatively easy to place the mounting groove in the mounting groove. A large space area is formed. Therefore, it is easy to absorb the deformation of the packing by using this relatively large space area, and the volume absorbability is improved. Therefore, when the high pressure is applied to the packing, it is possible to prevent the packing from contacting the other member entirely. It is possible. Therefore, it is possible to suppress the occurrence of problems such as a decrease in seal surface pressure and oil scraping due to packing, and to improve the sealing performance of the sealing device by extending the packing.

  In addition, since a wedge-shaped space region surrounded by the groove side surface of the mounting groove, the protrusion and annular base portion of the packing, and the other member is formed, oil is brought to the high pressure side by the wedge action or the wedge effect exhibited by this space region. It is possible to make it easy to return. Accordingly, the sealing performance of the sealing device can be improved by extending the packing.

Sectional drawing of the principal part of the packing with which the sealing apparatus which concerns on the Example of this invention is equipped. Comparative explanatory view showing the deformation state in the packing groove in the sealing device according to the conventional example, the comparative example and the embodiment of the present invention. Comparison graph showing the relationship between the internal pressure and the volume variation in the sealing device according to the conventional example, the comparative example, and the embodiment of the present invention. Sectional drawing of the principal part of the packing with which the sealing device which concerns on the other Example of this invention is equipped. The principal part perspective view of the projection part with which the sealing device which concerns on the other Example of this invention is equipped. Illustration of damper mechanism Sectional drawing of the principal part of the packing with which the sealing apparatus which concerns on a prior art example is equipped. Sectional drawing of the principal part of the packing with which the sealing apparatus which concerns on a comparative example is equipped

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross section of a main part of a packing 11 provided in a sealing device according to an embodiment of the present invention. The packing 11 is provided on an outer peripheral surface of a damper shaft 52 in the damper mechanism 51 of FIG. The sealing device for reciprocating motion (axial reciprocating motion) is configured by mounting in the mounting groove 57. As described above, the damper mechanism 51 has a damper shaft (one member in claim 1) 52 having a piston 53 with an orifice 54 at the tip and a damper case elastically supported by a spring means 56 (claim 1). And a sealing device is incorporated between the damper shaft 52 and the damper case 55 in order to seal the oil O enclosed in the damper case 55. As shown in FIG. 2, the mounting groove 57 includes a cylindrical groove bottom surface 57a, an axially perpendicular planar high pressure side (oil side) groove side surface 57b, and an axially perpendicular planar low pressure side (atmosphere side) groove side surface 57c. It has a rectangular cross section.

  As shown in FIG. 1, the packing 11 includes an annular base portion 12 having a predetermined axial length L, and an annular stationary side lip 13 and a damper case that are in close contact with the groove bottom surface 57 a of the mounting groove 57. An annular sliding lip 14 that is slidably in close contact with the inner peripheral surface of the cylindrical portion 55 is integrally formed. The stationary lip 13 is formed obliquely from the annular base 12 in one axial direction (high pressure side) and radially inward (groove bottom side), and is sealed at one axial position on the inner peripheral surface 13a. An annular convex lip end 13b for locally increasing the surface pressure is provided. On the other hand, the sliding side lip 14 is formed obliquely from the annular base 12 in one axial direction (high pressure side) and radially outward (case side), and at one axial position on the outer peripheral surface 14a. An annular convex lip end 14b is provided for locally increasing the seal surface pressure. An annular pressure receiving groove 15 is formed between the lips 13 and 14.

  Further, the packing 11 has the following characteristic configuration.

  That is, the annular base 12 in the packing 11 forms an arc shape in the cross-sectional shape of the heel portion 12c from the outer peripheral surface 12a to the other end surface 12b in the axial direction (low pressure side), so that the annular base 12 is in a free state. 1 has a shape that does not protrude from the extended line 14c of the outer peripheral surface 14a of the sliding side lip 14 toward the damper case 55 (outer peripheral side, left side in FIG. 1). In other words, the annular base 12 is slid in the free state. The cross-sectional shape of the heel portion 12c from the outer peripheral surface 12a to the end surface 12b of the annular base portion 12 is formed in an arc shape so as not to protrude from the extension line 14c of the outer peripheral surface 14a of the moving side lip 14 toward the damper case 55. Has been. The outer peripheral surface 12a of the annular base 12 faces the inner peripheral surface of the damper case 55 through a predetermined radial gap. Since the outer peripheral surface 14a of the sliding lip 14 in the free state is tapered (conical surface) and has a straight section, the extension line 14c is also tapered and has a straight section. The outer peripheral surface 14a of the side lip 14 may have an arcuate or curved cross section. In this case, the extension line 14c also has an arcuate or curved shape.

  In addition, an axially perpendicular flat portion 12d having an annular shape is provided on the other end surface 12b in the axial direction of the annular base portion 12, and an annular, predetermined axial height h that is continuous on the circumference is provided on the flat portion 12d. A protrusion 16 is provided.

  2, when the packing 11 is mounted in the mounting groove 57 and brought into close contact with the damper case 55, the low-pressure side groove side surface 57c of the mounting groove 57 and the protrusion 16 of the packing 11 are shown. Further, a wedge-shaped space region 17 having an annular shape is formed so as to be surrounded by the annular base portion 12 (flat portion 12d and heel portion 12c) and the damper case 55. The wedge-shaped space region 17 is a combination of the space region 18 between the annular base 12 and the damper case 55 and the space region 19 between the protrusion 16 and the damper case 55.

  In the sealing device having the above-described configuration, the annular base portion 12 of the packing 11 has the heel portion 12c having a circular cross section, and the annular base portion 12 has a damper from an extension line 14c of the outer peripheral surface 14a of the sliding lip 14 in a free state. Since the case 55 has a shape that does not protrude toward the case 55, a relatively large space region 18 is formed on the damper case 55 side (outer peripheral side) of the annular base 12, and elastic deformation of the packing 11 is formed here. There is room for absorption. In addition to this, in the sealing device having the above-described configuration, the annular protrusion 16 that is circumferentially continuous is provided on the flat portion 12d of the end surface 12b of the annular base 12, so that the damper case 55 of the protrusion 16 is provided. A space region 19 is also formed on the side (outer peripheral side), and a room for absorbing elastic deformation of the packing 11 is also created here. Therefore, when the packing 11 is mounted in the mounting groove 57, the space region 17 formed in the mounting groove 57 is large, which makes it easy to absorb the elastic deformation of the packing 11 (volume (volume and space region of the packing 11). Since the pressure absorption) due to the reduction of the sum of the volumes of 17) is improved, it is possible to suppress the packing 11 from contacting the damper case 55 over the entire surface. Therefore, it is possible to suppress the occurrence of problems such as a decrease in the seal surface pressure and the oil scraping out by the packing 11 and to improve the sealing performance of the sealing device by extending the packing 11.

  Further, in the sealing device having the above configuration, when the packing 11 is mounted in the mounting groove 57 and is in close contact with the damper case 55, the low-pressure side groove side surface 57c of the mounting groove 57, the protrusion 16 of the packing 11, and the annular base 12 (flat Since the wedge-shaped space region 17 surrounded by the portion 12d and the heel portion 12c) and the damper case 55 is formed, oil (oil film) in the space region 17 is formed by the wedge action or wedge effect exhibited by the space region 17. Can be easily returned to the high-pressure side. Therefore, the sealing performance of the sealing device can also be improved by this.

  Next, since this inventor performed the comparative test about the sealing device of the said structure, the content and result are demonstrated.

The specimens are the following three types.
(1) Conventional Example Product The conventional example product is a sealing device including the packing 62 according to the conventional example shown in FIG. As shown in the figure, the annular base 63 of the packing 62 is formed such that the cross-sectional shape of the heel portion 63a is a corner end, and the annular base 63 extends from an extension line 65c of the outer peripheral surface 65b of the sliding side lip 65 in a free state. The damper case 55 has a shape that protrudes toward the outer periphery (the left side in the figure).
(2) Comparative Example Product As shown in FIG. 8, the comparative example product is a sealing device including a packing 11 having a shape in which the protruding portion 16 is omitted from the packing 11 according to the above-described embodiment (FIG. 1). The configuration other than omitting the protrusion 16 is the same as that of the packing 11 according to the above-described embodiment (FIG. 1).
(3) Example Product The Example product is a sealing device including the packing 11 according to the above-described example (FIG. 1).

  When each of the three types of specimens is mounted in the mounting groove 57, the initial state shown in the left column diagram of FIG. 2 is obtained. In the conventional product, when the sliding side lip 65 is in close contact with the damper case 55, a relatively small space region 66 is formed on the outer peripheral side of the annular base 63. In the comparative product, when the sliding lip 14 is in close contact with the damper case 55, a relatively large space region 18 is formed on the outer peripheral side of the annular base portion 12. In the embodiment product, when the sliding side lip 14 is in close contact with the damper case 55, a relatively large space region 18 is formed on the outer peripheral side of the annular base 12, and a space region 19 is further formed on the outer peripheral side of the protrusion 16. Therefore, a large space region 17 is formed even in comparison with the comparative example product.

  When the internal pressure P due to oil acts from the initial state, each specimen is elastically deformed as shown in the right column diagram of FIG. The right column diagram of FIG. 2 shows a state when the “volume” consisting of the volume of each specimen and the volume of each space region 66, 18, 17 has changed by a certain amount, and is a graph diagram of FIG. In other words, the horizontal axis: the timing of point A in the volume change amount ΔV corresponds to this. Therefore, each elastic deformation state in the right column diagram of FIG. 2 shows the state of each plot x, y, z on the A point on the horizontal axis: volume change ΔV in the graph of FIG.

  In this state, as shown in the right column view of FIG. 2, the conventional example product covers the entire surface from the lip end 65a of the sliding side lip 65 to the heel portion 63a of the annular base 63. Contacting the damper case 55, the space area 66 disappears, and as shown in the graph of FIG. 3, it is no longer elastically deformable. Therefore, in the conventional example product, the seal surface pressure is dispersed and reduced as early as this point, and in a situation where high-frequency vibration is input and high-viscosity oil is used, the heel portion 63a scrapes the oil (oil film) to the low pressure side.

  On the other hand, in the comparative product, the packing 11 is not in full contact with the damper case 55 and the space region 18 is maintained a little as shown in the right column of FIG. As described above, the packing 11 can be further elastically deformed (volume change).

  Similarly, in the example product, as shown in the right column diagram of FIG. 2, the packing 11 is not in full contact with the damper case 55 and the space region 17 is maintained. Furthermore, the packing 11 can be further elastically deformed (volume change), but since the volume of the space region 17 is larger than that of the comparative product, further elastic deformation (volume change) is possible. . Therefore, according to the example product, it is possible to further elastically deform (change in volume) compared to the comparative example product. Therefore, since the volume absorbability is set larger in the example product than in the conventional product as well as the comparative example product, the sealing performance can be improved accordingly.

In addition, about the Example of the said invention, the following matters can be demonstrated additionally.
(A) Although the cross-sectional shape of the heel portion 12c is an arc shape in the above embodiment, it may be a tapered shape as shown in FIG. 4 instead. In the example of FIG. 4, the sectional line of the heel portion 12c is disposed on the extended line 14c of the outer peripheral surface 14a of the sliding side lip 14 in the free state (the inclination angle of the heel portion 12c with respect to the packing center axis is the sliding side). The inclination angle of the heel portion 12c may be larger than the inclination angle of the outer peripheral surface 14a of the sliding side lip 14 (smaller from the extension line 14c). Not possible because it protrudes).
(B) In the above embodiment, the protrusions 16 are continuous on the circumference, but instead of this, they may be discontinuous on the circumference as shown in FIG. It is also conceivable to provide a plurality of notches on the front end surface of the protrusion 16 that is continuous on the circumference.
(C) The material of the packing 11 may be a sealing material such as urethane in addition to rubber.
(D) In the above embodiment, the packing 11 is mounted in the mounting groove 57 provided on the outer peripheral surface of the damper shaft 52. Instead, the packing 11 is mounted in the mounting groove 57 provided on the inner peripheral surface of the damper case 55. Anyway. In this case, the mounting groove 57 opens radially inward, and in the structure of the packing 11, the stationary lip 13 is disposed on the outer peripheral side and the sliding lip 14 is disposed on the inner peripheral side. The damper case 55 corresponds to one member in claim 1 and the damper shaft 52 corresponds to the other member.

DESCRIPTION OF SYMBOLS 11 Packing 12 Ring base part 12a, 14a Outer peripheral surface 12b End surface 12c Heel part 12d Flat part 13 Stationary side lip 13a Inner peripheral surface 13b, 14b Lip end 14 Sliding side lip 14c Extension wire 15 Pressure receiving groove 16 Protrusion part 17, 18, 19 Space area 51 Damper mechanism 52 Damper shaft (one member)
53 Piston 54 Orifice 55 Damper case (the other member)
56 Spring means 57 Mounting groove 57a Groove bottom surface 57b, 57c Groove side surface

Claims (3)

A reciprocating seal that seals between the two members by mounting a packing in a mounting groove provided in one of the two members that reciprocally move relative to each other and slidably contacting the other member. The packing is a reciprocating seal that integrally includes an annular base, a stationary lip that is in close contact with the bottom surface of the mounting groove, and a sliding lip that is slidably in close contact with the other member. In the device
The annular base portion has an arc-shaped cross-sectional shape of the heel portion from the circumferential surface facing the other member to the end surface, and the other side from the extension line of the circumferential surface of the sliding lip when the annular base portion is free. It has a shape that does not protrude to the member side of
A reciprocating sealing device, wherein an end surface of the annular base portion includes a flat portion having a plane perpendicular to the axis, and a continuous or discontinuous protrusion is provided on the flat portion. A reciprocating seal that seals between the two members by mounting a packing in a mounting groove provided in one of the two members that reciprocally move relative to each other and slidably contacting the other member. The packing is a reciprocating seal that integrally includes an annular base, a stationary lip that is in close contact with the bottom surface of the mounting groove, and a sliding lip that is slidably in close contact with the other member. In the device
The annular base portion has a tapered heel section from the circumferential surface facing the other member to the end surface, and the other side from the extended line of the circumferential surface of the sliding lip when the annular base portion is free. It has a shape that does not protrude to the member side of
A reciprocating sealing device, wherein an end surface of the annular base portion includes a flat portion having a plane perpendicular to the axis, and a continuous or discontinuous protrusion is provided on the flat portion. The reciprocating sealing device according to claim 1 or 2,
When the packing is mounted in the mounting groove and is in close contact with the other member, a groove side surface of the mounting groove, a projection and an annular base of the packing, and a wedge-shaped space region surrounded by the other member are formed. A sealing device for reciprocating motion.

Images