JPH0614135Y2 - Lip seal - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a lip-type seal used as a shaft sealing device in various rotary devices such as a compressor of a cooler.

[Conventional technology]

Conventionally, as shown in FIG. 2 as a lip type seal,
PT where the inner diameter part (102) extends to the sealed space (A) side in the axial direction
A lip member (101) made of a resin material such as FE, a metal backup ring (105) provided on the atmosphere (B) side of the lip member (101), and an outer diameter portion of the PTFE lip member (101) ( Gasket (106) provided on the sealed space (A) side of 103), and these lip members (101), backup ring (105) and gasket
(106) is a metal outer ring (10
The one composed of 7) and is widely known.

This lip-type seal is fitted on the inner peripheral surface of the device housing (110) in the outer ring (107), and the outer peripheral groove of the outer ring (107).
By the O-ring (109) attached to the (108), the housing
While maintaining airtightness with (110),
The inner space (102) of (1) is brought into sliding contact with the rotating shaft (111) to form a cylindrical sealing sliding surface (112), so that a sealed space is formed.
Leakage of the fluid to be sealed from (A) to the atmosphere (B) side is prevented.

[Problems to be solved by the device]

However, since PTFE is a stable material, it is excellent as a sealing material against special lubricating oils and corrosive fluids, but on the other hand, it is poor in elasticity and therefore the lip member (101)
Is made of PTFE, the surface pressure with the shaft (111) cannot be increased so much. In addition, the sealed sliding surface (1
In the case of the PTFE lip member (101) having the shape shown in the figure in which 12) is formed in a cylindrical shape and the seal width is set large, as shown in FIG. 2, the peak of the surface pressure on the sealing sliding surface (112) (P)
However, there is a tendency that the distribution is biased toward the atmosphere (B) side. this is,
It is considered that bending stress generated in the curved portion (104) of the lip member (101) acts due to the fitting with the shaft (111). Therefore, the fluid to be sealed easily enters from the tip (112a) of the sealing sliding surface (112), which has a small surface pressure, and is especially suitable for lip-type seals installed in equipment such as car cooler compressors. High sealing performance is required, and improvement is desired.

The present invention has been made in view of such problems, and an object of the present invention is to provide a lip-type seal having high sealing performance.

[Means for Solving the Problems]

The lip type seal according to the present invention is located on the sealed space side,
A first lip member whose inner diameter portion extends toward the atmosphere side and slides airtightly with the shaft; and on the atmosphere side, the inner diameter portion extends toward the sealed space side and is in close contact with the outer peripheral surface of the inner diameter portion of the first lip member. And a second lip member, wherein the first lip member is provided with a pressure guiding hole that connects the pressure guiding space formed between the lip members and the sealed space. Further, in this configuration, the inner diameter portion of the second lip member is located at a position corresponding to the sealed space side portion of the sealed sliding surface between the first lip member and the shaft. It is preferable that the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral surface of the inner peripheral portion of the inner peripheral surface of the inner peripheral portion contact closely.

[Action]

According to the present invention, since the inner diameter portion of the first lip member extends toward the atmosphere side, the surface pressure peaks on the sealing sliding surface between the inner diameter portion and the shaft are formed unevenly on the sealed space side. It Then, since the pressure of the sealed space is introduced into the pressure guiding space between the first lip member and the second lip member through the pressure guiding hole, the fluid pressure is balanced on both sides of the first lip member, Moreover, since the pressure in the pressure guiding space acts radially inward on the inner diameter portion of the second lip member, the inner diameter portion of the first lip member is tightened from the inner diameter portion of the second lip member. A load is added and good sealing performance is demonstrated.

The tightening load by the inner diameter portion of the second lip member is the first at a position corresponding to the sealed space side portion of the sealed sliding surface.
By acting on the inner diameter portion of the lip member, a large surface pressure peak is formed in the sealing space side portion of the sealing sliding surface, so that higher sealing performance can be achieved.

〔Example〕

The present invention will be described below with reference to an embodiment shown in FIG.

This lip-type seal is located on the sealed space (A) side and is in the atmosphere (B).
The PTF in which the inner diameter part (2) extending to the side slides airtightly with the shaft (15)
A first lip member (1) made of E, a metal backup ring (5) in close contact with the surface of the outer diameter portion (3) of the lip member (1) on the side opposite to the sealed space, and the atmosphere (B) side There is a sealed space (A)
The inner diameter portion (7) extending toward the side is the inner diameter portion of the first lip member (1)
An elastomer-made first part (8a), which is in close contact with the outer peripheral surface of (2) and in which the metal reinforcing ring (9) is embedded and which extends in a cylindrical shape and which is in contact with the backup ring (5) at the end (8a). A metal outer ring that holds the second lip member (6), the first lip member (1), the backup ring (5), and the second lip member (6) together by pressing them together on the outer diameter side. (10) and are provided.

Between both lip members (1) (6) where inner diameter (2) (7) is in close contact, and outer diameter (3) (8) is in close contact with backup ring (5) in between , An annular pressure guiding space (C) is formed, and this pressure guiding space (C) is the outer diameter portion of the first lip member (1).
It communicates with the sealed space (A) through a pressure guide hole (11) provided through (3) and the backup ring (5).

The lip-type seal of the present embodiment having the above-mentioned configuration is composed of the outer ring (1
In (0), it is fitted on the inner peripheral surface of the housing (14) of the device,
The O-ring (13) fitted in the outer peripheral groove (12) of the outer ring (10) maintains airtightness between the outer ring (10) and the housing (14), and the inner diameter portion of the first lip member (1) made of PTFE. (2) airtightly slides on the rotating shaft (15) to form a cylindrical sealed sliding surface (1
6) prevents the fluid to be sealed from leaking from the sealed space (A) to the atmosphere (B) side.

Here, the first lip member (1) on the sealed space (A) side is
Since the inner diameter portion (2) extends toward the atmosphere (B) side, the pressure of the sealed space (A) on the surface in contact with the sealed space (A) causes the first lip member (1) and the shaft ( 15), it acts to push open between them, but at the same time, this pressure is introduced into the pressure guiding space (C) formed on the anti-sealing space side through the pressure guiding hole (11), Since the fluid pressure is balanced on both sides of the first lip member (1), the force for pushing the sealing sliding surface (16) is not generated.

Further, the inner diameter part (2) of the first lip member (1) is the atmosphere (B).
Since it extends toward the side, due to the bending stress of the curved portion (4), a surface pressure peak (P) unevenly distributed on the sealed space (A) side is formed on the sealing sliding surface (16), and the sealing function is improved. It has an effective surface pressure distribution. Moreover, the sealed space introduced in the pressure guiding space (C)
The pressure from (A) acts so as to press the inner diameter portion (7) of the second lip member (6) toward the inner side in the radial direction, so that the inner diameter portion (7) is applied to the first lip member (1). ) Of the inner diameter part (2) of the first lip member (1) against the outer peripheral surface of the first lip member (1) as shown in FIG. By sealing the contact position (7a) of the inner diameter portion (7) of the second lip member (6) with the position (16a) biased to the sealed space (A) side in the sealing sliding surface (16), Space (A)
It is possible to obtain a large surface pressure peak (P) that is unevenly distributed on the side,
The reliability of sealing can be made high.

[Effect of device]

As described above, according to the lip-type seal of the present invention, since the inner diameter portion of the first lip member that airtightly slides on the shaft extends to the atmosphere side, the surface pressure peak on the sealing sliding surface is unevenly distributed to the sealed space side, Further, the fluid pressure is balanced on both sides of the first lip member, and the inner diameter portion of the first lip member is tightened by the second lip member that receives the pressure radially inward. , Excellent sealing performance can be obtained. Then, by bringing the second lip member into contact with a position deviated to the sealed space side in the inner diameter portion of the first lip member, a large surface pressure peak unevenly distributed on the sealed space side is surely formed, and further high sealing is achieved. Can be expected.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of the present invention, and FIG. 2 is a half sectional view showing a conventional example. (1) …… first lip member, (2) (7) …… inner diameter part (6) …… second lip member, (11) …… pressure guide hole (15) …… shaft, (16) …… Sealed sliding surface (A) …… Sealed space, (B) …… Atmosphere, (C) …… Pressure guiding space

Claims (2)

[Scope of utility model registration request] 1. A first lip member located on the sealed space side, the inner diameter portion of which extends toward the atmosphere side and which airtightly slides on a shaft,
It is on the atmosphere side, and the inner diameter portion extends toward the sealed space side.
Second lip member in close contact with the outer peripheral surface of the inner diameter portion of the lip member, and the first lip member has a pressure guiding hole that communicates the pressure guiding space formed between these lip members with the sealed space. A lip-type seal characterized by being provided with. 2. The inner diameter portion of the second lip member is at a position corresponding to the sealed space side portion of the sealing sliding surface between the first lip member and the shaft, and the outer circumference of the inner diameter portion of the first lip member. The lip seal according to claim 1, wherein the lip seal is in close contact with the surface.