Mechanical seal

Patent metadata

Field	Value
Publication number	US-9644745-B2
Application number	US-201414910393-A
Country	US
Kind code	B2
Filing date	Oct 8, 2014
Priority date	Nov 12, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A mechanical seal ( 100 ) includes a sleeve ( 130 ) fixed to a rotating shaft ( 200 ), wherein the sleeve ( 130 ) has: a first annular portion ( 131 ) that has a step having an inner diameter and an outer diameter on a sealed fluid (F) side thereof that are larger than those of on an opposite side thereto, an inner peripheral surface of a small diameter portion ( 131 a ) on the first annular portion ( 131 ) is fitted on the rotating shaft ( 200 ), and a stationary ring ( 110 ) is disposed on the small diameter portion ( 131 a ), a rotating ring ( 120 ) is disposed between a large diameter portion ( 131 b ) and an inner peripheral surface of the rotating ring ( 120 ) is sealed, S 2 ÷S 1 ≦1 is satisfied where S 1 is a sliding area between the stationary ring ( 110 ) and the rotating ring ( 120 ), S 2 is a pressure receiving area where the stationary ring ( 110 ) receives a pressure effect of the rotating ring ( 120 ) due to a pressure of the sealed fluid (F).

First claim

What is claimed is:

1. A mechanical seal for sealing an annular gap between a rotating shaft and a housing, comprising:
a stationary ring provided on a housing side;
a rotating ring that is disposed on a sealed fluid side with respect to the stationary ring and rotates together with the rotating shaft;
a pressing member that presses the rotating ring toward the stationary ring; and
a sleeve fixed to the rotating shaft,
wherein the sleeve has: a first annular portion that has a step having an inner diameter and an outer diameter on a sealed fluid side thereof that are larger than those of on an opposite side to the sealed fluid side thereof; an enlarged diameter portion that enlarges in diameter from an end portion of the first annular portion on the sealed fluid side toward a radially outer side; and a second annular portion that extends from an end portion of the enlarged diameter portion on a radially outer side thereof toward the opposite side,
an inner peripheral surface of a small diameter portion on the opposite side with respect to the step on the first annular portion is fitted on an outer peripheral surface of the rotating shaft, and the stationary ring is disposed on an outer peripheral surface side of the small diameter portion,
the rotating ring is disposed in a state in which an annular gap between an outer peripheral surface of a large diameter portion on the sealed fluid side with respect to the step on the first annular portion and an inner peripheral surface of the rotating ring is sealed,
a space surrounded by the large diameter portion, the enlarged diameter portion, and the second annular portion is configured such that a sealed fluid flows therein, and the pressing member is disposed in the space, and
S2÷S1≦1 is satisfied where S1 is a sliding area between the stationary ring and the rotating ring, S2 is a pressure receiving area where the stationary ring receives a pressure effect of the rotating ring due to a pressure of the sealed fluid; and
wherein the rotating shaft includes a small diameter portion on which the sleeve is disposed and a large diameter portion disposed on a side further toward the sealed fluid from the small diameter portion, and the sleeve is disposed such that the enlarged diameter portion comes into intimate contact with a step portion of the rotating shaft, and
the enlarged diameter portion is provided with a rotation locking portion that is formed by bending a part of the enlarged diameter portion toward the sealed fluid side at bending line, the part being formed by cutting the enlarged diameter portion along a line joining both ends of the bending line, and locks the sleeve by being fitted into a notch formed on the large diameter portion of the rotating shaft.

2. The mechanical seal according to claim 1 , further comprising a seal ring made of an elastic body that seals an annular gap between an outer peripheral surface of the large diameter portion of the first annular portion and the inner peripheral surface of the rotating ring,
wherein the pressing member is a spring that has one end side coming into intimate contact with a corner portion between the enlarged diameter portion and the second annular portion, and another end side being held by a holding member that is provided so as to be slidable against the outer peripheral surface of the large diameter portion of the first annular portion, and
the holding member pressed by the spring is provided so as to come into intimate contact with the seal ring.

3. The mechanical seal according to claim 1 , further comprising a seal ring made of an elastic body that seals an annular gap between an outer peripheral surface of the large diameter portion of the first annular portion and the inner peripheral surface of the rotating ring,
wherein the pressing member is a spring that has one end side coming into intimate contact with a corner portion between the enlarged diameter portion and the second annular portion, and another end side being held by a holding member that is provided so as to be slidable against the outer peripheral surface of the large diameter portion of the first annular portion, and
the holding member pressed by the spring is provided so as to come into intimate contact with the seal ring.

Assignees

• Eagle Ind Co Ltd

Inventors

• Nakahara Nobuo
• Ikeda Yasuhiro

Classifications

• F16J15/3452

  the pressing force resulting from the action of a spring · CPC title

• F16J15/3448 Primary

  the pressing force resulting from fluid pressure · CPC title

• F16J15/38

  sealed by a packing · CPC title

• F16J15/348

  Pre-assembled seals, e.g. cartridge seals · CPC title