JPH0680060U - Slipper seal back ring - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a slipper seal having a small frictional force, excellent sealing property and durability, and excellent eccentricity following property. [Structure] Seal ring 11 and back ring of substantially rectangular cross section
In the slipper seal 10 configured by combining 21 with, the back ring 21 is sandwiched between the outer peripheral lip 23 and the inner peripheral lip 24, the valley portion 25 between the outer peripheral lip and the inner peripheral lip, and the upper and lower valley portions. And a base portion 22 having a substantially H-shaped cross section.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a slipper seal buckling having low friction and improved sealability and durability.

[0002]

[Prior art]

 As shown in cross sections in FIGS. 9 (a) and 9 (b), the slipper seal 1 used as a sealing device for fluid pressure equipment is made of a synthetic resin such as PTFE or a thermoplastic elastomer material such as polyurethane or polyester. This is a sealing device configured by combining a seal ring 2 having a substantially rectangular cross section and a synthetic rubber back ring (O ring, square ring) 3 having a circular or rectangular cross section, and as shown in FIG. The piston 5 is mounted in a mounting groove 6 of a substantially rectangular cross section provided on the outer periphery of the piston 5, and the pressing force due to the compressive deformation of the back ring 3 is applied to the seal ring 2 so that the sealability between the seal ring 2 and the cylinder 4 is improved. Have secured.

Although the mounting groove 6 is provided on the piston 5 in the illustrated example, the mounting groove 6 may be provided on the cylinder 4 side. Such slipper seals are normally used in fluid seals for pistons or rods, and have been required to have characteristics such as low friction and low speed operation. With the recent increase in pressure and compactness of fluid pressure equipment, the operating environment temperature has risen, and there is a demand for improved durability and sealability under such conditions.

By the way, as described above, the sealability of the slipper seal is obtained by compressing and deforming a compression type back ring such as an O-ring or a square ring when the slipper seal is mounted in the mounting groove. Therefore, the amount of compressive deformation (crushing amount) affects the performance of the slipper seal.

That is, when the amount of compressive deformation is increased, the contact force of the seal ring with respect to the other surface is increased, so that the sealability and the eccentricity followability are initially improved, but on the contrary, the seal force is increased due to the increase in the friction force. , And the amount of wear of the back ring is increased, or the back ring is deformed or damaged, which causes a problem of deterioration of sealing property and durability. Especially when the operating temperature is high, the shrinkage and settling (permanent strain) due to the deterioration of the buckling material are accelerated and the durability is affected. On the other hand, when the amount of compressive deformation of the buckling is set to a small value, the reverse operation is observed, and friction and wear are reduced, but the sealability and eccentricity followability are insufficient.

The slipper seal having an O-ring-shaped back ring shown in FIG. 9 (a) is worn or damaged by twisting due to the cross-sectional shape of the O-ring under high-pressure or pressure switching frequency. Etc. may occur. The slipper seal with a square back ring as shown in Fig. 9 (b) is basically suitable for high pressure and high frequency use due to its stable shape, but it has the same crushing rate. Since the compression force of the square ring in this case is about four times that of the O-ring, the sealing performance is improved but the friction force tends to be high. Therefore, it has been difficult in the prior art to obtain a slipper seal having a small frictional force and excellent sealability and durability.

[0007]

[Problems to be solved by the device]

 An object of the present invention is to provide a slipper seal buckling having a small frictional force, excellent sealing property and durability, and excellent eccentricity following property.

[0008]

[Means for Solving the Problems]

 In order to achieve such an object, the present inventors have repeatedly studied conventional slipper seals, and basically applied a pressing force to the seal ring of the back ring in order to obtain low friction and durability. The inventors completed the present invention knowing that the eccentricity following property is improved by the expansion action of the buckling fluid pressure and the expansion action of the buckling fluid pressure.

That is, since the conventional slipper seal is a squeeze seal in combination with an O-ring or a square ring, the durability and the sealability tend to largely change depending on the crushing amount of the back ring, and the fluid pressure The expansion effect of buckling due to is hardly used.

[0010] In practice, the buckling is worn and twisted during use, and the deterioration of the material due to the influence of heat and the like causes the hardness to increase and the crushing amount to decrease due to shrinkage, resulting in deterioration of durability and sealability. Tend to bring.

Therefore, the inventors of the present invention have the idea that, in order to improve the sealing property and durability of the slipper seal, the back ring may be positively utilized with fluid pressure like U packing. Friction is reduced by providing a lip on the outer and inner peripheral surfaces on both pressure sides of the back ring and introducing the fluid pressure into the valley between the lip on the outer and inner peripheral surface to utilize the expanding action of the lip. Moreover, they found that a slipper seal with excellent sealing properties and durability could be obtained, and completed the present invention.

Therefore, the gist of the present invention is a slipper seal configured by combining a seal ring having a substantially rectangular cross section and a back ring, and at least at the time of mounting, a fixed side peripheral surface of the seal ring and the mounting side. An outer peripheral lip and an inner peripheral lip that are in contact with the bottom surface of the groove and extend in both pressure directions, a valley portion between the outer peripheral lip and the inner peripheral lip, and a base portion sandwiched between the upper and lower lip and the valley portion. The back ring of the slipper seal is characterized by having a substantially H-shaped cross section.

Another aspect of the present invention is a slipper seal configured by combining a seal ring and a back ring, each of which has a substantially rectangular cross section, in a pressure side of the seal ring at least when mounted in both pressure directions. The cross-section is composed of an outer peripheral lip and an inner peripheral lip that come into contact with the peripheral surface and the bottom surface of the mounting groove, a valley portion between the outer peripheral lip and the inner peripheral lip, and a base portion sandwiched between the upper and lower valley portions, and is substantially H. The back ring of the slipper seal is characterized in that the tip of a convex portion provided on the peripheral surface of the base projects from the tip of the lip of the letter-shaped buck ring.

Further, according to another aspect of the present invention, in order to more effectively obtain low friction and eccentricity followability, the tip of the lip of the back ring is located closer to the peripheral surface of the base. It is a back ring of a slipper seal configured to project.

[0015]

[Action]

 Next, the operation of the present invention will be described in more detail with reference to the accompanying drawings. The same reference numerals denote the same members throughout the drawings. 1 to 3 are schematic partial cross-sectional views showing a back ring of a slipper seal according to the present invention, a combination of the seal ring and the back ring, and a state when the slip ring is mounted in a mounting groove. According to the present invention, the back ring 21 of the slipper seal 10 is provided with outer and inner peripheral lips 23 and 24 on the outer circumference and inner circumference of both side surfaces of the base portion 22 in the axial direction. It is made of a soft elastic material such as synthetic rubber having a substantially H-shaped cross section provided with a valley portion 25.

Then, a force for expanding the outer peripheral lip 23 and the inner peripheral lip 24 of the fluid pressure introduced into the valley portion 25 acts on the seal ring 11, and the contact force to the mating movement surface corresponding to the fluid pressure is applied. Has obtained a sealing property. In order to make it easier to introduce the fluid pressure to each trough 25, the lip 23, 24 is cut at least at the lip apex on the seal ring side so as to extend over the outer and inner circumferential surface of the back ring 21 and the trough 25. Fluid pressure introducing means such as the notch groove 38 may be provided. Reference numeral 15 indicates a notch provided in the seal ring.

As shown in FIG. 3, the slipper seal 10 configured by combining the back ring 21 and the seal ring 11 as described above has the back ring 21 in contact with the groove bottom surface 7 of the mounting groove 6. In the illustrated example, the piston 5 is mounted.

Explaining the shape of the valley portion 25, the depth of the valley portion 25 is set according to the usage conditions of the slipper seal, in particular, the friction characteristics and pressure conditions. The lower the working pressure, the deeper the sealing property. It is effective in terms of the above, and when the width is installed in combination with the seal ring 11, the purpose is to secure a space for introducing the fluid pressure to the open end of the valley 25 in the sandwiched state. Can be reached.

Further, FIGS. 4 to 6 show another embodiment of the slipper seal according to the present invention, according to which it is used under a relatively low pressure condition in which the expansion action of the lip by the fluid pressure is hard to work. In this case, by giving a slight amount of crushing to the base portion of the back ring 21, it is possible to secure the sealing property under low pressure or no pressure.

Therefore, according to the preferred embodiment shown in FIG. 4 of the present invention, in the slipper seal 10 configured by combining the seal ring 11 and the back ring 21 each having a substantially rectangular cross section, at least when mounted in both pressure directions. An outer peripheral lip 23 and an inner peripheral lip 24 that come into contact with the fixed-side peripheral surface 12 of the seal ring 11 and the bottom surface 7 of the mounting groove 6, a trough portion 25 between the outer peripheral lip 23 and the inner peripheral lip 24, and upper and lower troughs. The tips of the protrusions 31 and 32 provided on the peripheral surface of the base project from the tips 26 and 27 of the lip of the back ring 21 having a substantially H-shaped cross section composed of the base 22 sandwiched between the portions 15. It may be configured to. The convex portion may be provided on either side, for example, only on the seal ring 11 side.

Further, as shown in FIG. 5, in order to more effectively obtain the low friction property and the eccentricity following property, the tip portions 26 and 27 of the lips 23 and 24 of the back ring 21 have the base portion 22. It may be configured to project from the peripheral surfaces 33, 34. That is, the peripheral surfaces 33 and 34 are formed as concave surfaces, which is the opposite of the case of FIG. The concave surface may be provided on only one of them. FIG. 6 is a schematic explanatory view showing a state in which the slipper seal ring of FIG. 4 is mounted on a relative moving surface such as a piston or a cylinder, as in the case of FIG.

According to the present invention, since the back ring 21 is composed of the compression portion and the lip portion as described above, the portions substantially subjected to the compression deformation are the valley portions on the both side surfaces of the back ring 21. Since it is only the portion of the base portion 22 sandwiched by the 25, the frictional force of the slipper seal can be reduced. Even if the crushing amount decreases due to wear of the back ring 21, thermal deterioration, wear of the seal ring, etc., the sealing performance is maintained by the expansion action of the fluid pressure introduced into the valley portion 25 on the lips 23, 24. As a result, durability and eccentricity followability can be improved.

In addition, the tips 26 and 27 of the lips 23 and 24 of the back ring 21 are projected from the peripheral surfaces 33 and 34 of the base 22, so that at least one of the outer and inner peripheral surfaces of the back ring is By making the central portion an annular concave surface, the amount of compression of the base portion 22 can be reduced or substantially eliminated, and the frictional force can be further reduced.

The above-described configuration of the lip tip and the peripheral surface of the base portion 22 may be only on one of the outer and inner surfaces of the buckling, and the base portion of one peripheral surface may be a convex portion and the other peripheral surface. The object of the present invention can be achieved even if it is configured as a concave portion.

Further, the axial end surface of each lip is provided with means for introducing a fluid pressure, such as a protrusion and / or a notch groove extending over the seal ring side and the trough, so that troughs on both side surfaces are formed. The fluid pressure is surely introduced into 25, and the sealing action is improved by ensuring the expansion action of the lip. In this case, it is desirable to provide similar fluid pressure introducing means 15 on the pressure side surface 14 of the seal ring 11. See FIG. 2 and FIG.

[0026]

【Example】

 The operation of the present invention will be described more specifically with reference to the embodiments shown in FIGS. 1 to 3 and 4 to 6, respectively. FIG. 1 is a one-sided sectional view of a back ring of a slipper seal according to the present invention. In the figure, the back ring 21 has an outer peripheral lip 23, an inner peripheral lip 24, and a valley 25 between the outer inner lip and the outer peripheral lip 23 on both sides of the base 22 in the pressure direction.

The slipper seal 10 shown in FIG. 2 consisting of a seal ring 11 and a back ring 21 having a substantially rectangular cross section is mounted in a mounting groove 6 provided on the outer peripheral surface of the piston 5 as shown in FIG. The outer peripheral surface of the ring 11 is in contact with the inner peripheral surface of the cylinder tube 4. In the illustrated example, the notch grooves 38 for introducing the fluid pressure to the valleys 25 are provided at appropriate intervals in the circumferential direction.

FIG. 7 and FIG. 8 are graphs showing a comparison of the sealability and frictional force between the slipper seal having the back ring according to the present invention and the conventional slipper seal. The product of the present invention is a slipper seal having the structure shown in FIG. 2, and the conventional product is a slipper seal using an O-ring shown in FIG. 9 (a).

The test condition of the sealing performance (leakage amount) was as follows. A cylinder body with an inner diameter of 50 mm was assembled with a piston body in which two pistons with slipper seals were connected, and pressure was applied to the pressure chamber between both pistons. In this state, the piston body was driven from the outside and the cumulative leak amount was measured.

The test condition of the frictional force was carried out by a test apparatus using the above-mentioned seal performance test, and the same slipper seal was installed in two pistons, and after a predetermined pressure was applied to the pressure chamber between the two pistons and the mixture was left stationary for 1 minute. , The starting frictional force when the piston body was moved at a speed of 50 m / sec was measured and converted into one seal value.

According to the present invention, the sealability (leakage amount) is reduced to about 1/2 of that of the conventional one, and the frictional force is approximately 1/2 at low pressure and slightly lower even at high pressure. It becomes a value. The buckling with such a configuration can be easily designed according to various specifications by changing the setting such as the lip beam allowance, the depth and width of the trough, and the provision of multiple troughs. I also found out.

As described above, the slipper seal of the present invention is composed of the seal ring and the back ring having a substantially H-shaped cross section composed of four lips provided on the upper and lower outer peripheral surfaces of the base, so When assembled in the groove, the outer and inner lips and the peripheral surface of the base contact the seal ring and the bottom of the mounting groove, but only the base part is compressed by mounting, and depending on the setting, the base part may be compressed. It is possible to reduce the volume of the compressed portion of the portion of, and it is also possible to adopt a configuration in which there is no compressed portion.

Next, FIGS. 4 and 5 are schematic cross-sectional views of another buckling according to the present invention. As described above, the slipper seal of FIG. 4 is compared with that of FIG. The only difference is that the convex portions 31 and 32 provided on the outer and inner peripheral surfaces of the base portion 22 that come into contact with the back ring side peripheral surface 12 of the seal ring 11 and the groove bottom surface 7 protrude from the tips 26 and 27 of the lips 23 and 24. Take the same configuration except that

The protrusions 31 and 32 each have a width dimension of about 1/10 or less of the width of the back ring 21, and when mounted, the seal ring 11 has a seal ring side surface including the peripheral surface of the lip 23. The diameter of the lip tip 26 on the seal ring side is preferably set to be approximately the same as the diameter of the back ring side peripheral surface 12 of the seal ring so as to contact the seal ring.

With such a configuration, the force due to the compression of the convex portions 31 and 32 of the base portion 22 of the back ring at the time of low pressure, and the expansion force due to the compression and the fluid pressure of the lip at the time of pressurization are applied to the seal ring. Since it works, the sealability against pressure conditions from low pressure to high pressure is more effectively ensured.

Further, the buckling of FIG. 5 has a more complete lip shape in which the tips 26 and 27 of the outer and inner lips protrude beyond the peripheral surfaces 33 and 34 of the base 22, thereby substantially compressing the base. Is configured not to.

By adopting such a configuration, the expansion force of the lip due to the fluid pressure introduced into the valley gives a contact force corresponding to the fluid pressure to the mating movement surface of the seal ring, so that the sealing property of the slipper seal, In addition to improving friction characteristics, the contact between the seal ring and the back ring is secured over the entire surface, so rolling and twisting of the back ring are eliminated and the sealing performance is stable.

Further, when it is used for swinging / rotating motion, a so-called co-rotation phenomenon in which the seal ring and the back ring relatively rotate is prevented, and the occurrence of back ring wear is reduced. The effect was obtained.

[0039]

[Effect of device]

 As described above in detail, according to the present invention, the sealing amount of the back ring can be set by appropriately setting the beam margin amount of the lip, the depth of the valley portion, and the compression amount of the convex portion of the central portion of the base portion. Since the pressing force against can be set in a fairly wide range, it is possible to obtain a slipper seal that can be used for low pressure to high pressure while maintaining low wear resistance.

Also, the lip of the back ring is made to project to the seal ring side and the bottom of the mounting groove respectively, and the lip seal type is formed by relatively recessing the base part, so that lip packing such as U packing is achieved. The same action and effect as those of the sealing mechanism can be obtained, and the low friction property, the sealing property and the durability are improved.

Moreover, with such a lip seal shape, the contact force of the back ring to the seal ring is concentrated near the lip tip, so that the contact force of the seal ring to the mating movement surface is also on both end sides of the seal ring. The oil film will not easily enter between the seal ring and the mating movement surface, and the sealing performance will be improved.

Therefore, the sealability (leakage amount) of the slipper seal using the back ring according to the present invention is reduced to about 1/2 of that of the conventional slipper seal, and the friction resistance is approximately 1%. It has decreased from / 2 to about 4/5. Further, the eccentricity following property of the slipper seal is also improved by the expansion action of the lip portion of the back ring due to the fluid pressure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a buckling according to the present invention.

FIG. 2 is a sectional view of a slipper seal having a back ring according to the present invention.

FIG. 3 is a cross-sectional view showing a mounted state of a slipper seal combined with a back ring according to the present invention.

FIG. 4 is a cross-sectional view of another embodiment of the buckling according to the present invention.

FIG. 5 is a cross-sectional view of another embodiment of the buckling according to the present invention.

FIG. 6 is a cross-sectional view showing a mounted state of the slipper seal combined with the back ring shown in FIG.

7 is a graph comparing the sealing performance of the slipper seal according to the present invention shown in FIG. 2 and the conventional O-ring type slipper seal.

FIG. 8 is a graph comparing the friction resistances of the slipper seal according to the present invention shown in FIG. 2 and a conventional O-ring type slipper seal.

9A and 9B are cross-sectional views of one side of a conventional slipper seal using a back ring. FIG. 9A is a case where the back ring is an O-ring, and FIG. 9B is a case where the back ring is a square ring.

FIG. 10 is a cross-sectional view showing a mounted state of the slipper seal by the conventional back ring shown in FIG. 9 (a).

[Explanation of symbols]

1: Slipper seal 2: Seal ring 3: Back ring (O-ring, square ring) 4: Cylinder tube 5: Piston 6: Mounting groove 7: Bottom of groove 10: Slipper seal 11: Seal ring 21: Back ring 22: Base 23,24: Lip 25: Valley 26,27: Lip tip 31,32: Convex part 33,34: Peripheral surface 35,36: Convex ridge 38: Fluid pressure introducing means

Claims (3)

[Scope of utility model registration request] 1. A pair of cylindrical members that move relative to each other,
With a back ring of a slipper seal, which is mounted in an annular groove of a substantially rectangular cross section provided on the peripheral surface of one of the members to seal fluid pressure, and which is configured by combining a seal ring and a back ring of a substantially rectangular cross section. The outer peripheral lip 23 and the inner peripheral lip 24, which contact the fixed-side peripheral surface of the seal ring and the bottom surface of the mounting groove at least during mounting and extend in both pressure directions.
And a valley portion 25 between the outer peripheral lip and the inner peripheral lip, and a base portion 22 sandwiched between the upper and lower valley portions, the cross section having a substantially H shape, the back of the slipper seal. ring. 2. The back ring for a slipper seal according to claim 1, wherein a tip of a convex portion provided on the peripheral surface of the base portion projects radially from the tip of the lip. 3. The back ring for a slipper seal according to claim 1, wherein the tip of the lip projects radially from the peripheral surface of the base.