FR2459926A1 - HYDROSTATIC BALANCING LIPSTICK FOR PRESSURIZED FLUID - Google Patents

Abstract

LIP SEAL THAT CONTAINS TWO PIECES OF WHICH ONE IS ELASTOMERIC AND THE OTHER IS METAL. THE FIRST PIECE PRESENTING A FACE NOTCHED SO AS TO CONSTITUTE TWO V-SHAPED LIPS THE SECOND BEING CHAMFRAINED AND SUPPORTS THE V-LIPS OF THE SECOND PIECE.

Description

* All the so-called "lip seals" currently marketed

are designed on the same sealing principle.

  The fluid to be sealed acts directly on the lips, and pla

that these on their range, thus ensuring sealing.

  The very principle limits their use in translation (approximately Im / sec); the possible number of half-cycles is not guaranteed above I0 and, moreover, friction is high and

  proportional to the operating pressure.

The subject of the invention is a seal whose forces to which they are subjected are balanced in order to reduce the frictional forces, which results in:

- long-term potential.

  - a very high translation speed due to the absence of heating. The seal is shown as a seal on shaft I, it goes from

the sealing on the bore is identical.

  The seal is made up of two parts:

  IO) the actual seal 2, made of elasto

mother. 20) a metal part 3, one end of which is chamfered and which bears on the inner part of the lips of the

elastomer seal.

  The fluid P is assumed on the left, that is to say on the side of the tab of the seal opposite the lips 4 and 5, which is contrary to

which is usually done.

  It should be noted, however, that the seal according to the invention is

  capable of sealing in two opposite directions, although primarily

cipe, it was not designed for this use.

The seal itself is housed in a body 6 whose shape

me can be cylindrical or prismatic.

  The part 2, made of elastomer, has two faces, preferably two parallel faces 7 and 8, one face 9 subjected to pressure, the fourth face has the two lips 4 and 5, on which comes to bear and press the chamfer I0. The passage II has only an accessory role, and is intended to allow the fluid to I

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escape in the event of overpressure.

The pressure of the fluid gives rise to a force F and two forces F2, both perpendicular to F, and antagonistic one

compared to each other.

  The force F gives birth to two forces FI, which, by decompo

sition, give rise to two forces F IO, of opposite signs.

  We note that F IO is opposite to F2 on each of the diameters

inside and outside.

By a judicious dimensioning of the geometry of the joint, (rai-

IO odor, opening angle) it is possible to make the FIO forces balance the F2 forces, which results in a

  zero friction component, therefore zero friction.

  Given this state of equilibrium, it follows: I) that the seal can operate both in translation and in rotation.

2) that the linear speed is not limited by the sealing system

  dearly. 3) that there is almost no wear, thus ensuring a lifetime

  of tens of millions of cycles.

4) that the sealing is also ensured, as for the seals

classic lipsticks, when the pressure acts on the side of the lips.

  ) that the fluid to be sealed can be a non-lubricating fluid. 6) that the system is in equilibrium whatever the pressure under

which one we use.

  Given these advantages, this seal can find applications

cations wherever "dry" friction is disruptive

(servo-control-servo cylinders, vibration cylinders) and also

ment: -when a long service life is sought

  -when there is composition of a circular movement and a movement-

rotatable.

- when the system to be sealed is subjected to alternating

high frequency movement (several hundred Hertz).

  - when a high pressure is applied simultaneously and

high speed.

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Claims (3)

- CLAIMS - -R E V E N D I C À T I O N S- I / -Lip seal characterized in that it comprises two parts, one of which is made of elastomer and the other is metallic - the first part with a notched side -   lée so as to constitute two V-shaped lips. The second being chamfered and bears on the lips in V of the second room. 2 / - Lip seal, characterized in that all the forces involved are hydrostatically balanced, whatever the hydraulic pressure values.   3 / -Lip seal characterized in that the sealing of the fluid takes place without friction on the sealing faces. 3 pages.