JP2006177501A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device by which sliding resistance of a seal lip 10 to an opposed member such as a housing is reduced, thus the durability of the seal lip 10 can be improved. <P>SOLUTION: A sliding part 15 of the seal lip 10 comprises a belt-like section (normally contacting section) 16 which normally comes in contact with the opposed member, and belt-like sections (contact/separate sections) 17, 18 positioned on both sides of the section 16 in the axial direction, and coming into contact only when under pressure-load. In the sections 17, 18 which come into contact only when under pressure-load, a plurality of axially long grooves 19, 20 or projections are arranged on the perimeter. This sealing device is used, e.g. as a bonded piston-seal (BPS) in an automatic variable transmission. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sealing device according to a sealing technique, and more particularly, for example, suitable for use as a bonded piston seal (BPS) in an automatic transmission (AT, CVT, etc.) of a vehicle such as an automobile. The present invention relates to a sealing device. The sealing device of the present invention is used not only in the field of automobiles but also in the fields of agricultural machinery or industrial machinery.

  Conventionally, a bonded piston seal 51 shown in FIG. 6 is known as a sealing device used in an automatic transmission of a vehicle such as an automobile. The bonded piston seal 51 is supplied from a port 53 provided in a housing 52. A piston 54 which is displaced by a pressure load to press the clutch plate 55, and a seal lip 56 which is provided on the piston 54 and slidably contacts the housing 52 to seal the pressure (patent) Reference 1).

However, according to the above prior art, as shown in FIG. 7, the seal lip 56 is pressed against the sliding surface of the housing 52 by the pressure load and the contact width w increases, so that the sliding resistance (friction) increases. There is a drawback that it is easy to wear. 7A shows an atmospheric pressure state in which no pressure load is applied to the seal lip 56. When pressure is applied to the seal lip 56 from this atmospheric pressure state, FIG. As shown, when the contact width increases from w ₁ to w ₂ and the pressure increases, the contact width further increases from w ₂ to w _{3 as} shown in FIG.

Japanese Patent Laid-Open No. 11-351273

  SUMMARY OF THE INVENTION In view of the above, the present invention has an object to provide a sealing device that can reduce the sliding resistance of a seal lip with respect to a mating member such as a housing and thus can increase the durability of the seal lip. To do.

  In order to achieve the above object, a sealing device according to claim 1 of the present invention is a sealing device having a seal lip that is slidably in close contact with a mating member such as a housing. A belt-shaped part that is always in contact with the member, and a belt-shaped part that is in contact with only the pressure load located on both sides in the axial direction of the part. A plurality of grooves or protrusions are arranged side by side on the circumference.

  According to a second aspect of the present invention, there is provided a sealing device according to the first aspect, wherein the sealing device is a bonded piston seal used in a clutch switching portion of an automatic transmission, and the bonded piston seal. Has a piston that reciprocates in the axial direction within the housing, and a seal lip that is attached to the piston and slidably contacts the housing.

  As in the sealing device according to claim 1 of the present invention having the above-described configuration, when a plurality of axially long grooves are arranged side by side on the circumference in a portion that contacts only at the time of pressure load in the sliding portion of the seal lip, Since the groove is provided, it is possible to reduce the contact area of the seal lip with the mating member when pressure is applied. Further, when a projection is provided instead of the groove, the projection comes into contact with the mating member and the periphery of the projection is lifted from the mating member, so that the contact area can also be reduced. Therefore, in any case, an increase in contact area due to pressure load can be suppressed.

  Further, since the groove has a shape that is long in the axial direction, it acts as a lubricating oil supply path that actively supplies lubricating oil to the sliding portion. When the protrusion is provided instead of the groove, since the periphery of the protrusion is lifted as described above, the lubricating oil supply path is formed immediately on the side of the protrusion.

  In addition, about the site | part which always contacts with the other party member in the sliding part of a seal lip, a groove | channel or protrusion is not provided here from a viewpoint of preventing the leak at atmospheric pressure.

  The present invention has the following effects.

  That is, in the sealing device according to the first aspect of the present invention, a plurality of axially long grooves or protrusions are arranged side by side on the circumference at a portion that contacts only at the time of pressure load in the sliding portion of the seal lip. It is possible to suppress an increase in the contact area due to the pressure load, and it is possible to positively supply lubricating oil to the sliding portion. Therefore, as described above, as expected, the sliding resistance of the seal lip with respect to the mating member such as the housing can be reduced, and the durability of the seal lip can be increased.

  Further, in the sealing device according to claim 2 of the present invention, the function and effect of claim 1 can be obtained in the bonded piston seal used in the clutch switching portion of the automatic transmission.

  The present invention includes the following embodiments.

(1) A groove structure that is parallel to the shaft is provided on both sides of the pressure side and the clutch plate side on the circumference of the surface that comes into contact with the pressure load of the seal lip.
(2) By providing a groove on the circumference of the surface to be contacted by the pressure load as in (1) above, it is possible to suppress an increase in the contact area due to the pressure load and to actively lubricate near the seal portion. Oil can be supplied, which is effective for low friction.
(3) By providing the groove positions alternately on the circumference on the pressure side and the clutch plate side, it is possible to prevent uneven wear in a portion without a groove and improve workability.
(4) Although the same effect can be obtained even if the groove is provided with a protrusion instead of this, there is a possibility that the contact state of the lip tip part with the housing may partially rise. The stability of the contact state is higher in the groove. However, the protrusion is effective when supplying a large amount of lubricating oil to the lip tip.

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

  FIG. 1 shows a cross section of a main part in a state in which a bonded piston seal 1 which is a sealing device according to an embodiment of the present invention is incorporated in a clutch switching part in an automatic transmission of a vehicle such as an automobile. It is configured as follows.

  That is, first, an annular housing 2 formed by pressing a sheet metal or the like is provided, and an annular cylinder chamber 2c between the outer peripheral cylindrical portion 2a and the inner peripheral cylindrical portion 2c in the housing 2 is similarly annular. A bonded piston seal 1 to be presented is incorporated so as to reciprocate in the axial direction (vertical direction in the figure).

  The bonded piston seal 1 includes a cancel seal 3 held in a housing 2, a return spring 4 interposed between the bonded piston seal 1 and the cancel seal 3, and a housing 2 to be pressed against the bonded piston seal 1. When the hydraulic pressure as the load pressure is introduced from the pressure port 6 provided in the housing 2 into the pressure chamber (piston chamber) 7 together with the clutch plate 5 having a multilayer structure disposed below the housing 2. Then, it is displaced downward against the elasticity of the return spring 4 to press the clutch plate 5 and fasten the clutch. When the hydraulic pressure is pulled, the return spring 4 returns upward due to the elasticity of the return spring 4 to disengage the clutch. Therefore, the bonded piston seal 1 is sometimes referred to as an automatic transmission piston because of this reciprocating function.

  The bonded piston seal 1 has an annular piston member (metal ring) 8 formed by sheet metal pressing or the like, and housings 2 are provided on the outer peripheral portion and the inner peripheral portion of the piston 8 respectively. Annular seal lips 10, 11 that are slidably in close contact with the sliding surfaces (the inner peripheral surface of the outer peripheral cylindrical portion 2a and the outer peripheral surface of the inner peripheral cylindrical portion 2c) are attached (vulcanized and bonded). The seal lips 10, 11 are provided as a part of a film-like rubber-like elastic body 9 attached to the upper surface of the piston 8, and the rubber-like elastic body 9 includes the seal lips 10, 11, A shock-absorbing stopper 12 and the like that abuts on and away from the inner surface of the flat surface portion 2d of the housing 2 are provided.

  A cylindrical pressing portion 13 for pressing the clutch plate 5 downward is integrally formed on the outer peripheral portion of the piston 8, and is slidably in close contact with the inner peripheral surface of the pressing portion 13. A seal lip 14 is attached to the outer periphery of the cancel plate 3.

As shown in FIG. 2 in an enlarged manner, the seal lip 10 provided on the outer peripheral portion of the piston 8 has a sliding portion 15 having a mountain-shaped cross section that is slidably in close contact with the sliding surface of the housing 2. The sliding portion 15 is pressed against the sliding surface of the housing 2 by the hydraulic pressure introduced into the pressure chamber 7, and the contact width w gradually increases. That is, in FIG. 2, (A) shows an atmospheric pressure state where no pressure load acts on the seal lip 10, and when pressure acts on the seal lip 10 from this atmospheric pressure state, as shown in FIG. When the contact width gradually increases from w ₁ to w ₂ and the pressure increases, the contact width further increases from w ₂ to w _{3 as} shown in FIG. Is increased as described above. Therefore, in the bonded piston seal 1, the following measures are taken.

That is, the sliding portion 15 of the seal lip 10 has a belt-like portion (constant contact portion) 16 having the above-described constant width w ₁ that always comes into contact with the sliding surface of the housing 2 and both axial sides thereof. There are belt-like parts (contact / separation part, the width is the dimension obtained by subtracting w ₁ from w ₃ ) 17 and 18 that are in contact with each other only at the time of a pressure load. A plurality of grooves 19 and 20 each having a long shape in the axial direction are formed side by side on the circumference.

  A number of grooves 19 and 20 are provided at the same pitch over the entire circumference, and the end on the constant contact portion 16 side is on the boundary line between the constant contact portion 16 and the contact and separation portions 17 and 18, respectively. It is provided to be located.

  Further, each of the grooves 19 and 20 is depicted by a single line in FIG. 2 for the convenience of drawing, but actually, as shown in FIG. 3, a predetermined circle other than a predetermined axial length is used. It has a circumferential width, and thus has a predetermined plane area. Therefore, the contact area of the seal lip 10 with respect to the housing 2 is reduced by the amount of the grooves 19 and 20 formed.

  In the bonded piston seal 1 having the above-described configuration, a plurality of grooves 19 and 20 are provided side by side on the contact and separation portions 17 and 18 of the sliding portion 15 of the seal lip 10. , 20, the contact area of the seal lip 10 with the housing 2 when pressure is applied is reduced. Therefore, an increase in the contact area due to the pressure load can be suppressed as compared with the case where the grooves 19 and 20 are not provided.

  Further, since the grooves 19 and 20 are each formed in a shape that is long in the axial direction, the peripheral pressure oil is positively supplied to the sliding portion 15 as lubricating oil through the grooves 19 and 20. Therefore, the lubrication state of the sliding part 15 can be maintained satisfactorily.

  Therefore, the bonded piston seal 1 that can reduce the sliding resistance of the seal lip 10 with respect to the housing 2 and can increase the durability of the seal lip 10 as described in the intended purpose of the present invention. Can be provided.

  In the above embodiment, the seal lip 10 disposed on the outer peripheral portion of the piston 8 in the bonded piston seal 1 is taken as an example, and the grooves 19 and 20 are provided in the sliding portion 15. The seal lip 11 disposed on the inner peripheral portion and the seal lip 14 disposed on the outer peripheral portion of the cancel seal 3 are similarly provided with grooves 19 and 20 to reduce their sliding resistance and increase durability. be able to.

  Further, in the above embodiment, as shown in FIGS. 2 and 3, the groove 19 provided in the contact / separation portion 17 on the pressure chamber 7 side (upper side in the figure) and the contact / separation on the clutch plate 5 side (upper and lower side in the figure). The groove 20 provided in the part 18 is arranged so that the positions on the circumference coincide with each other. As shown in FIGS. 4 and 5, the grooves 19 and 20 are formed on the pressure chamber 7 side and the clutch plate 5 side. The arrangement may be alternately arranged on the circumference. In this case, uneven wear of the portions without the grooves 19 and 20 can be suppressed, and the processing can be facilitated.

  Furthermore, the grooves 19 and 20 may be provided with protrusions (not shown) instead. In this case, a relative groove is formed between the adjacent protrusions. The same effects as the example can be achieved.

Sectional drawing of the principal part of the automatic transmission clutch switching part incorporating the sealing device based on the Example of this invention Explanatory drawing which shows the change of the contact state of the seal lip in the sealing device (A) is an enlarged sectional view of a seal lip in the sealing device, and (B) is a view in the direction of arrow A in FIG. Explanatory drawing which shows the change of the contact state of the seal lip in the sealing device which concerns on the other Example of this invention. (A) is an enlarged sectional view of a seal lip in the sealing device, and (B) is a view in the direction of arrow B in FIG. Sectional view of the main part of the automatic transmission clutch switching part incorporating the sealing device according to the conventional example Explanatory drawing which shows the change of the contact state of the seal lip in the sealing device

Explanation of symbols

1 Bonded piston seal (sealing device)
2 Housing (mating member)
2a Outer cylinder part 2b Inner cylinder part 2c Cylinder chamber 2d Plane part 3 Cancel seal 4 Return spring 5 Clutch plate 6 Pressure port 7 Pressure chamber 8 Piston 9 Rubber elastic body 10, 11, 14 Seal lip 12 Stopper 13 Press part 15 Sliding part 16 Always contact part (band-like part always in contact)
17, 18 Contact / separation part (band-like part that contacts only when pressure is applied)
19, 20 groove

Claims (2)

In a sealing device (1) having a sealing lip (10) slidably in close contact with a mating member (2) such as a housing,
The seal lip (10) has a belt-like part (16) that always contacts the sliding member (15) against the mating member (2) and a pressure load located on both sides in the axial direction of the part (16). And the belt-like part (17) (18) which contacts only
A sealing device characterized in that a plurality of grooves (19), (20) or protrusions that are long in the axial direction are arranged on the circumference in the parts (17), (18) that contact only at the latter pressure load. The sealing device of claim 1.
The sealing device is a bonded piston seal (1) used in a clutch switching portion of an automatic transmission, and the bonded piston seal (1) is a piston (8) reciprocating in an axial direction in a housing (2). And a sealing lip (10) which is attached to the piston (8) and slidably contacts the housing (2).

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