JP2009270679A - Sealing structure and sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure and a sealing device, capable of reducing an influence of change in installation space on the sealing device. <P>SOLUTION: The sealing structure is configured to seal an annular gap between a shaft 4 and a housing 5 having a shaft hole into which the shaft 4 is inserted. The sealing structure includes a radially-recessed annular groove 41 formed in the outer peripheral surface 40 of the shaft 4, an annular member 20 fitted in the radially-recessed groove 41 with a clearance interposed between the bottom 44 of the groove 41 and itself, a first seal member 10 installed in the radially-recessed groove 41 on the groove opening side rather than the annular member 20 so as to make sliding contact with the inner peripheral surface 50 of the housing 5 and make close contact with the outer peripheral surface 21 of the annular member 20, an axially-recessed annular groove 43 at a radial position of the side face 42 of the radially-recessed groove 41 where the annular member 20 overlaps irrespective of the existence of displacement between the two members in a direction perpendicular to the shaft, and a second seal member 30 fitted in the axially-recessed groove 43 so as to make close contact with the bottom surface 43a of the axially-recessed groove 43 and the surface of the annular member 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealing structure and a sealing device for sealing an annular gap between a shaft and a shaft hole provided in a housing.

  Conventionally, as shown in FIG. 4, as a sealing device for sealing an annular gap between a shaft and a shaft hole provided in a housing, a hydraulic device such as a hydraulic cylinder used as an actuator of a construction machine or a general industrial machine is used. Is used. 4A and 4B are schematic cross-sectional views showing the mounting state of the sealing device according to the prior art, where FIG. 4A is a mounting state when there is no eccentricity between the cylinder and the piston, and FIG. Each wearing state is shown.

  A lip packing 100 as a sealing device according to the prior art is provided as a sealing device for a piston in a hydraulic cylinder in order to maintain hydraulic pressure in a reciprocating motion of a rod.

  As shown in FIG. 4A, the lip packing 100 seals an annular gap between an inner peripheral surface 201 of a cylinder 200 as a housing and an outer peripheral surface 301 of a piston 300 as a shaft. It is used by being attached to an annular groove 302 formed on the outer peripheral surface 301 of 300. The lip packing 100 has seal lips 101 and 102 on the high pressure side of the inner and outer peripheral surfaces, and an annular groove 103 having a U-shaped cross section recessed in the axial direction is provided on the end surface on the high pressure side. In the lip packing 100, the inner peripheral seal lip 101 is in close contact with the groove bottom surface 303 of the annular groove 302, and the outer peripheral seal lip 102 is in sliding contact with the inner peripheral surface 201 of the cylinder 200. An annular gap between the piston 300 and the outer peripheral surface 301 is sealed.

  The lip packing 100 has a crushing margin at the lip portion. That is, the lip packing 100 has an outer diameter dimension larger than a diameter dimension of the inner peripheral surface 201 of the hydraulic cylinder 200 and an inner diameter dimension of the groove bottom surface 303 of the annular groove 302 in the portion where the seal lips 101 and 102 are formed. It is smaller than the dimensions.

  Therefore, when the lip packing 100 is mounted, the inner peripheral seal lip 101 is crushed (expanded) in the outer diameter direction by the groove bottom surface 303 of the annular groove 302, and the outer peripheral seal lip 102 is inner diameter by the inner peripheral surface 201 of the cylinder 200. Collapsed (compressed) in the direction. Thereby, the inner peripheral seal lip 101 reliably contacts the groove bottom surface 303 of the annular groove 302, the outer peripheral seal lip 102 reliably contacts the inner peripheral surface 201 of the cylinder 200, and the inner peripheral seal lip 101 and the outer peripheral seal lip 102 Sealing performance is exhibited. In the drawing, the lip packing 100 is shown in a state before deformation in order to make the crushing margin easy to understand, which is different from the state of the actual mounting state.

  In such a hydraulic cylinder, the crushing allowance of the lip packing 100 is uniform, and in order to prevent galling between the cylinder 200 and the piston 300, there is a wear between the cylinder 200 and the piston 300. Bearing parts such as rings and esleees are installed.

However, when the size, material, and mounting position of the bearing parts are inappropriate, or when the lateral load applied to the piston 300 is large, as shown in FIG. Deviation in the direction perpendicular to the axis may occur between the piston 300 and the axis 300a (eccentricity of the piston 300). FIG. 4B shows a cross section including the axis 200a and the axis 300a among the cross sections of the piston 300 and the cylinder 200.

  At this time, the space in the direction perpendicular to the axis in the mounting space of the lip packing 100, that is, the space (CS) between the inner peripheral surface 201 of the cylinder 200 and the groove bottom surface 303 of the annular groove 302 is present. In the region (left side of the figure), the space is widened by the amount of eccentricity β of the piston 300 (CS + β), and in a certain region (right side of the figure), the space is narrowed by the amount of eccentricity β (CS.β). .

  In such a state, in the region where the space is widened, the crushing allowance for the groove bottom surface 303 of the inner peripheral seal lip 101 is reduced or eliminated, and the sealing performance is lowered and oil leakage occurs. On the other hand, in a region where the space is narrowed, the crushing margin of the lip packing 100 with respect to the inner peripheral surface 201 of the piston 200 increases, and friction increases to cause wear. That is, in the lip packing 100, uneven wear increases due to an increase in friction, and due to non-uniform surface pressure on the circumference, the pressure holding performance is reduced and oil leakage occurs.

In addition, there exists a thing described in patent document 1 as a related technique.
Japanese Utility Model Publication No. 62-151470

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a sealing structure and a sealing device that can reduce the influence of a change in mounting space on the sealing device. .

In order to achieve the above object, the sealing structure in the present invention comprises:
A sealing structure for sealing an annular gap between two members of a housing having a shaft and a shaft hole into which the shaft is inserted,
An annular radial groove provided so as to be recessed in the radial direction on the surface of one of the two members;
An annular member mounted with a gap between the radial groove and the groove bottom;
A first seal that is mounted closer to the groove opening than the annular member with respect to the radial groove, slidably contacts the surface of the other member of the two members, and closely contacts the surface of the annular member Members,
An annular axial groove provided so as to be recessed in the axial direction in a region overlapping with the annular member on the side surface of the radial groove on the side surface of the radial groove regardless of whether there is a deviation in a direction perpendicular to the axis between the two members When,
A second seal member mounted on the axial groove and in close contact with a bottom surface of the axial groove and slidably in contact with the surface of the annular member.

  According to this configuration, the gap provided between the annular member and the groove bottom of the radial groove absorbs the deviation in the direction perpendicular to the axis between the two members (deviation due to eccentricity), and the seal member and the contact partner It can suppress that a change arises in a contact state with.

That is, when the positional relationship in the direction perpendicular to the axis between the two members changes, the radial space of the mounting space for the annular member and the first seal member, that is, the surface of the other member and the groove bottom surface of the radial groove The space between is widened by a shift in a certain area, narrowed by a shift in a certain area, and becomes non-uniform in the circumferential direction. At this time, since a gap is provided between the groove bottom surface of the radial groove provided in one member and the annular member, the first seal member and the annular member It is possible to follow the members. Therefore, the space in the direction perpendicular to the axis in the mounting space of the first seal member, that is, the space between the surface of the other member and the annular member does not change, and the first seal member, the other member, and the annular member do not change. The contact state with is maintained as it was before the two members were displaced.

  Further, the axial groove in which the second seal member is mounted is provided in a region where the radial position overlaps with the annular member on the side surface of the radial groove regardless of whether or not there is a deviation in the direction perpendicular to the axis between the two members. Therefore, the second seal member is kept in contact with the annular member by sliding relative to the surface of the annular member.

  Therefore, even if a deviation in the direction perpendicular to the axis occurs between the two members, a change in the contact state of each seal member with the contact partner is suppressed, and an extreme uneven load is applied to the seal member due to the deviation between the two members. Is prevented from being added or the sealing performance is deteriorated.

In order to achieve the above object, a sealing device according to the present invention comprises:
A sealing device for sealing an annular gap between two members of a housing having a shaft and a shaft hole into which the shaft is inserted,
One of the two members is used by being attached to an annular radial groove provided on the surface of one member so as to be recessed in the radial direction and having an annular axial groove recessed in the axial direction on the side surface. In the sealing device,
A gap is provided between the radial groove and the groove bottom, and the radial groove and the radial position overlap each other regardless of whether or not there is a deviation in a direction perpendicular to the axis between the two members. An annular member to be mounted;
A first groove that is mounted on the groove opening side of the annular member with respect to the radial groove, slidably contacts the surface of the other member of the two members, and closely contacts the surface of the annular member. A sealing member;
A second seal member mounted on the axial groove and in close contact with a bottom surface of the axial groove and slidably in contact with the surface of the annular member.

  According to this configuration, the gap provided between the annular member and the groove bottom of the radial groove absorbs the deviation in the direction perpendicular to the axis between the two members, so that the seal member and the contact partner are in contact with each other. A change can be suppressed. Therefore, even if the mounting space is changed due to the deviation, the occurrence of an uneven load and a decrease in sealing performance are suppressed.

  As described above, according to the present invention, it is possible to reduce the influence of the change of the mounting space on the sealing device.

  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. .

(Example)
With reference to FIGS. 1-3, the sealing structure and sealing device based on the Example of this invention are demonstrated. FIG. 1 is a schematic half sectional view of a sealing device according to the present embodiment. FIG. 2 is a diagram for explaining the dimensional relationship of each member constituting the sealing structure according to the present embodiment, where (a) is a lip packing as a first seal member, and (b) is a seal ring as an annular member. (C) is a rubber ring as a 2nd sealing member, (d) is typical half sectional drawing of each mounting space of the sealing device formed by two members. FIG. 3 is a schematic cross-sectional view of the sealing structure according to the present embodiment, in which (a) shows no deviation (eccentricity) in the direction perpendicular to the axis between the two members, and (b) shows between the two members. Each case shows eccentricity.

  The sealing structure according to the present embodiment seals an annular gap between a shaft and a shaft hole provided in a housing in a hydraulic device such as a hydraulic cylinder used as an actuator for construction machinery, general industrial machinery, and the like by a sealing device. To do.

  As shown in FIG. 1, the sealing device 1 according to the present embodiment includes a lip packing 10 as a first seal member, a seal ring 20 as an annular member, and a rubber ring 30 as a second seal member. ing.

  With this sealing device 1, the sealing structure according to the present embodiment seals an annular gap between the piston 4 as a shaft and the hydraulic cylinder 5 as a housing, as shown in FIG. 3. In the present embodiment, in the state of use, the pressure on the upper side in the figure is configured to be increased by the fluid pressure (hydraulic pressure or pneumatic pressure). That is, in the use state, as shown in FIG. 3, the upper side becomes a high pressure (H) and the lower side becomes a low pressure (L) through the sealing device 1. Note that the fluid to be sealed is sealed on the high pressure side, and the fluid pressure by the fluid to be sealed may act on the low pressure side in the same way as the high pressure side, depending on the applied hydraulic and pneumatic equipment. In some cases, it may be atmospheric pressure. Moreover, depending on the applied hydraulic / pneumatic equipment, the upper side may be constantly at a high pressure, or may be intermittently at a high pressure.

  The lip packing 10 has an inner peripheral seal lip 11 and an outer peripheral seal lip 12 on the inner and outer peripheral surfaces, and has a groove 13 extending in an annular shape around the shaft on one side surface in the axial direction. This is a ring-shaped annular member and is called a so-called U-shaped packing. Examples of the material of the lip packing 10 include elastic materials such as nitrile rubber and polyurethane rubber.

  The seal ring 20 is an annular member whose half cross-sectional shape is substantially rectangular. Examples of the material of the seal ring 20 include resin materials and metal materials such as polytetrafluoroethylene (PTFE) and polyamide (PA).

  The rubber ring 30 is an annular member having a substantially circular determination surface shape. Examples of the material of the rubber ring 30 include elastic materials such as nitrile rubber, hydrogenated nitrile rubber, and fluorine rubber.

  An annular radial groove 41 formed so as to be recessed in the radial direction is provided on the outer peripheral surface 40 of the piston 4. An annular axial groove 43 formed so as to be recessed in the axial direction is provided on the side surface 42 of the radial groove 41. The lip packing 10 and the seal ring 20 are mounted in the radial groove 41, and the rubber ring 30 is mounted in the axial groove 43.

  In the lip packing 10 and the seal ring 20, the lip packing 10 is disposed on the groove opening side with respect to the radial groove 41, and the seal ring 20 is disposed on the groove bottom side.

In the lip packing 10, the inner diameter (D 11) of the inner peripheral seal lip 11 is set to be smaller than the outer diameter (D 21) of the seal ring 20. In the lip packing 10, the outer diameter (D 12) of the outer peripheral seal lip 12 is set to be larger than the diameter (D 50) of the inner peripheral surface 50 of the cylinder 5. Therefore, when the lip packing 10 is mounted in the radial groove 41, the inner peripheral seal lip 11 is in close contact with the outer peripheral surface 21 of the seal ring 20, and the outer peripheral seal lip 12 slides on the inner peripheral surface 50 of the cylinder 5. It is in a state of contact in a free state.

  The seal ring 20 has an inner diameter (D22) set larger than the diameter (D44) of the groove bottom surface 44 of the radial groove 41. Therefore, in a state where the seal ring 20 is mounted in the radial groove 41, the outer peripheral surface 21 contacts the inner peripheral seal lip 11 of the lip packing 10, but there is a gap (in between the inner peripheral surface 22 and the groove bottom surface 44. α) is formed.

  The axial groove 43 is provided in a region where the side surface 23 of the seal ring 20 and the radial position overlap each other on the side surface 42 of the radial groove 41. The rubber ring 30 is set such that the diameter (wire diameter: D31) of the circular cross section is larger than the depth (W43) of the axial groove 43. Therefore, when the rubber ring 30 is mounted in the axial groove 43, the rubber ring 30 is compressed in the axial direction by the groove bottom surface 43 a of the axial groove 43 and the side surface 23 of the seal ring 20.

  Thus, the gap between the seal ring 20 and the cylinder 5 is sealed by the lip packing 10, and the gap between the seal ring 20 and the piston 4 is sealed by the rubber ring 30, so that the piston 4 and the cylinder 5 are sealed. The annular gap between is sealed. In each drawing, the lip packing 10 and the rubber ring 30 are shown in a state where no external force is acting (the state before deformation) in order to make it easy to understand the dimensional relationship between the constituent members. It is different from the appearance.

  Here, a bearing component is installed between the piston 4 and the cylinder 5 to prevent eccentricity between the piston 4 and the cylinder 5 (shift in a direction perpendicular to the axis between the axis 4a and the axis 5a). Has been. However, when the size, material, and mounting position of the bearing component are inappropriate, eccentricity may occur even though the bearing component is mounted. Further, when the lateral load applied to the piston 4 is large, the eccentricity between the piston 4 and the cylinder 5 may not be sufficiently prevented by the bearing parts.

  As shown in FIG. 3B, when eccentricity occurs and the positional relationship in the direction perpendicular to the axis between the piston 4 and the cylinder 5 changes, the radial space in the mounting space of the sealing device 1, that is, A change occurs in the size of the space (CS) between the inner peripheral surface 50 of the cylinder 5 and the groove bottom surface 44 of the radial groove 41. That is, in a certain region (left side of the figure), the eccentric amount β is widened (CS + β), and in a certain region (right side of the diagram), it is narrowed by the eccentric amount β (CS.β). Therefore, the radial size of the mounting space is not uniform in the circumferential direction. FIG. 3B shows a cross section including the axis 4 a and the axis 5 a among the cross sections of the piston 4 and the cylinder 5.

  Thus, even if the mounting space (CS) of the sealing device 1 changes, according to the sealing structure according to the present embodiment, an uneven load is applied to the lip packing 10 and the rubber ring 30 that are seal members, It is possible to suppress the change in the contact state with the member, and to suppress the occurrence of uneven wear of the sealing device 1 and the deterioration of the sealing performance.

  Specifically, the gap α provided between the seal ring 20 and the piston 4 absorbs the eccentric amount β between the piston 4 and the cylinder 5, so that the lip packing 10, the seal ring 20, and the cylinder 5 It is possible to suppress changes in the contact state between the rubber ring 30, the seal ring 20, and the piston 4.

That is, since a clearance α is provided in the radial direction between the seal ring 20 and the piston 4 (groove bottom surface 44), the displacement in the direction perpendicular to the axis of the piston 4 and the cylinder 5 due to eccentricity is The lip packing 10 and the seal ring 20 can follow the cylinder 5, and the positional relationship in the direction perpendicular to the axis changes with the piston 4. At this time, the gap α between the seal ring 20 and the groove bottom surface 44 is widened by an eccentric amount β (α + β) in a certain region (left side in the figure).
In a certain region (the right side of the figure), it becomes narrower by the amount of eccentricity β (α−β). On the other hand, the radial space in the mounting space of the lip packing 10, that is, the space (C.S1) between the inner peripheral surface 50 of the cylinder 5 and the outer peripheral surface 21 of the seal ring 20 does not change, and the lip packing 10 The contact state between the cylinder 5 and the seal ring 20 is maintained in the contact state before the eccentricity.

  Further, the axial groove 43 in which the rubber ring 30 is mounted is in a region where the radial position overlaps the side surface 23 of the seal ring 20 regardless of whether the piston 4 and the cylinder 5 are eccentric on the side surface 42 of the radial groove 41. Is provided. The rubber ring 30 is slidably in contact with the side surface 23 of the seal ring 20. Accordingly, the seal ring 20 is displaced in the direction perpendicular to the axis with respect to the axial groove 43 due to the eccentricity, but the rubber ring 30 slides with respect to the side surface 23 of the seal ring 20, thereby the axial groove. The state sandwiched between the groove bottom surface 43a of 43 and the side surface 23 of the seal ring 20 is maintained.

  The dimensional relationship between the constituent members such as the size of the gap α and the position of the axial groove 43 can be set as appropriate within a range in which the above-described eccentric absorption effect can be exhibited. One specific example is illustrated below.

  First, in order to prevent interference between the inner peripheral surface 22 of the seal ring 20 and the groove bottom surface 44 of the radial groove 41 at the time of eccentricity, the gap α is set so as not to be smaller than the eccentric amount β. Specifically, at least half of the difference between the diameter (D50) of the inner peripheral surface 50 of the cylinder 5 and the diameter of the outer peripheral surface 40 of the piston 4, that is, the annular gap between the cylinder 5 and the piston 4. It is preferable to set it larger than the size in the radial direction. This is because the eccentric amount β does not become larger than the radial size of the annular gap unless the deformation of the cylinder 5 is taken into consideration.

  Further, the position of the axial groove 43 is such that the difference (DO43-D44) between the outer diameter and the diameter of the groove bottom surface 44 of the radial groove 41 is equal to the radial thickness t (D21-D22) of the seal ring 20. The seal ring 20 and the groove when the eccentric amount is the maximum (DI43-D44), preferably within a range smaller than t and the difference between the inner diameter and the diameter of the groove bottom surface 44 of the radial groove 41 (DI43-D44). It is preferable to set within a range equal to the size of the gap (α + β) between the bottom surface 44 and preferably larger than α + β. However, when (DO43-D44) is slightly larger than t and (DI43-D44) is slightly smaller than α + β, that is, a part of the axial groove 43 is radially formed from the side surface 23 of the seal ring 20. Even if the arrangement is such that the rubber ring 30 partially protrudes into the gap between the side surface 42 of the radial groove 41 and the side surface 23 of the seal ring 20 even when it is eccentric. Can be set as appropriate.

  In the present embodiment, the axial width (W20) of the seal ring 20 is substantially equal to the axial width (W41) of the radial groove 41. However, in the sealing device 1 according to the present embodiment, Since high sealing performance is not required for the seal ring 20 itself, the seal ring 20 can be appropriately set within a range in which the seal ring 20 does not follow the piston 4 at the time of eccentricity. For example, the axial width of the seal ring 20 may be smaller than the axial width of the radial groove 41, or the side surface 23 of the seal ring 20 and the side surface 43 of the radial groove 41 are always in contact with each other. Even in the case of such dimensions, for example, by setting the seal ring 20 so that the elastic force that the seal ring 20 receives from the lip packing 10 is larger than the frictional resistance between the side surface 23 and the side surface 43, the seal ring 20 is What is necessary is just to be able to suppress being dragged by the piston 4.

Specific numerical examples of the dimensions of the constituent members are as follows, for example. Note that this is an example, and is appropriately changed according to the specifications of the apparatus, and is not limited thereto.
D11: φ98.6 ± 0.6mm
D12: φ116.4mm
D21: φ100mm
D22: φ95mm
W20: 10mm
D30: φ96mm
D31: φ1.2mm
D44: φ93mm
DI43: φ96mm
DO43: φ99mm
D50: φ115mm
W41: 10mm
W43: 1mm

  In the above description, the case where the present embodiment is a sealing device for a piston has been described as an example, but it goes without saying that the present invention can be similarly applied to a sealing device for a rod. Further, it goes without saying that the present invention can be suitably applied even if the sealing device is mounted in an annular groove provided in the housing.

It is a typical half section view of the sealing device concerning this example. It is a figure explaining the dimensional relationship of each member which comprises the sealing structure which concerns on a present Example. It is typical sectional drawing of the sealing structure which concerns on a present Example. It is typical sectional drawing which shows the mounting state of the sealing device which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 10 Lip packing 11 Inner peripheral seal lip 12 Outer peripheral seal lip 13 Groove 20 Seal ring 21 Outer peripheral surface 22 Inner peripheral surface 23 Side surface 30 Rubber ring 4 Piston 40 Outer peripheral surface 41 Radial direction groove 42 Side surface 43 Axial groove 43a Groove bottom surface 44 Groove bottom 5 Cylinder 50 Inner circumferential surface

Claims (2)

A sealing structure for sealing an annular gap between two members of a housing having a shaft and a shaft hole into which the shaft is inserted,
An annular radial groove provided so as to be recessed in the radial direction on the surface of one of the two members;
An annular member mounted with a gap between the radial groove and the groove bottom;
A first seal that is mounted closer to the groove opening than the annular member with respect to the radial groove, slidably contacts the surface of the other member of the two members, and closely contacts the surface of the annular member Members,
An annular axial groove provided so as to be recessed in the axial direction in a region overlapping with the annular member on the side surface of the radial groove on the side surface of the radial groove regardless of whether there is a deviation in a direction perpendicular to the axis between the two members When,
A sealing structure comprising: a second seal member mounted in the axial groove and in close contact with a groove bottom surface of the axial groove and slidably contacting the surface of the annular member. A sealing device for sealing an annular gap between two members of a housing having a shaft and a shaft hole into which the shaft is inserted,
One of the two members is used by being attached to an annular radial groove provided on the surface of one member so as to be recessed in the radial direction and having an annular axial groove recessed in the axial direction on the side surface. In the sealing device,
A gap is provided between the radial groove and the groove bottom, and the radial groove and the radial position overlap each other regardless of whether or not there is a deviation in a direction perpendicular to the axis between the two members. An annular member to be mounted;
A first groove that is mounted on the groove opening side of the annular member with respect to the radial groove, slidably contacts the surface of the other member of the two members, and closely contacts the surface of the annular member. A sealing member;
A sealing device, comprising: a second seal member mounted in the axial groove and in close contact with a groove bottom surface of the axial groove and slidably contacting the surface of the annular member.

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