JPS62266268A - Seal construction - Google Patents

Abstract

PURPOSE:To sufficiently maintain durability even for a high pressure and a high speed of an air clutch, by providing an annular tension part, which connects a point end lip part of an annular seal member with the other end part of a reinforcing member, and forming a plurality of communication holes, which connect a hollow chamber with a pressure air chamber, in the annular tension part. CONSTITUTION:In case of an engine in rotation, when a clutch is connected, air of an air supply source 30 is forced to be fed to a pressure air chamber 7 between seals S passing through a control mechanism 29 and a pipe 28. Subsequently, the air, which is supplied passing through a pipe 26 or the like to a pressure air chamber 20 in a cylinder part 16, forces a pressure plate 19 to come into contact with a clutch disc 12. When the clutch is placed in a connection condition, a pressure in the pressure air chamber 7 between the seals S is equalized to the pressure in a hollow chamber 5, and tightening force F is generated by a seal width W of a lip part 1a of a seal member 1. Simultaneously with the above, tensile force is generated in a tension part 40, consequently an increasing rate of the tightening force F decreases in accordance with an increase to the high pressure of the hollow chamber 5. Accordingly, a heat generation amount in the lip part is suppressed to a small value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention primarily relates to an air seal used in an air clutch or the like that rotates at high speed.

(Prior Art and its Problems) As shown in FIG. 6, for example, a conventional seal has an I.
It has an i-plane O-shaped configuration and has an annular hollow chamber 5 inside. The hollow chamber 5 opens into a pressurized air chamber 7 of the seal mounting member.

In such a seal, the pressure in the hollow chamber 5 increases in proportion to the increase in the pressure in the pressure air chamber 7, and as a result, the tightening of the seal portion (width W) against the rotating member (input @ 13) is performed by a force F. is increasing. By the way, the tightening force is F.
is: F, = po7Cw, P is the air pressure in the hollow chamber 5 <K9/cti>, D is the seal n - inner diameter (α), W
is the seal width (atr).

By the way, air clutches near Id are trending toward higher pressure and higher rotation speeds due to higher output of engines, etc., and therefore the PV value (■ is the rotational speed of the rotating member) is also decreasing. As the PV value increases, the number 4 hook F of the tightening tool increases, and the amount of heat in the seal part W also increases in proportion to it, which exceeds the heat resistant temperature of the seal member 1 and causes seal burnout. .

(Object of the Invention) An object of the present invention is to provide a seal structure that can maintain sufficient durability even under high pressure and high rotation speed of an air clutch.

(Means for Achieving the Object) In order to achieve the above object, the present invention includes an annular seal member that comes into contact with a rotating member, an annular reinforcing member that is fitted into a seal mounting member, and an annular seal member. By connecting one end of the member in the axial direction and one end of the annular reinforcement part, the seal is formed into a C-shaped cross section, and the annular hollow chamber within the seal is connected to the pressurized air chamber of the seal attachment member. In the seal structure that opens toward the direction, an annular tension part is provided that connects the tip lip part of the annular seal member and the other end part of the reinforcing member, and the annular tension part has a plurality of parts that connect the hollow chamber and the pressurized air chamber. It forms several communicating holes.

(Example) First, to briefly explain the air clutch to which the seal according to the present invention is applied with reference to FIG. The clutch cover 15 is rotatably supported on the inner peripheral side of the case 14 via a bearing 17.
It is equipped so that it can be rotated integrally. A cylinder part 16 having a cavity 11 and a chamber 20 is integrally provided on the clutch cover 15, and a pressure plate 19 is fitted into the cylinder part 16 so as to be movable in the axial direction. 21 is a flywheel.

For example, a pair of seals S are attached to the inner peripheral surface of the case 14 at intervals in the axial direction, and an annular pressure air chamber 7 is formed between the seals S. The pressurized air chamber 7 communicates with the pneumatic chamber 20 via the annular passage 25 of the input shaft 13 and the pipe 26, and communicates with the air supply source 30 via the pipe 28 and the pneumatic control mechanism 29.

In FIG. 1 showing an enlarged view of the seal S, the seal S is equipped with a rubber sealing member 1 having a rectangular cross-section on the inner circumferential side, a rubber annular reinforcing member 2 on the outer circumferential side, and both members 1 .2, that is, one end of the lubrication side (A side) opposite to the pressure air chamber 7, are integrally connected by a metal annular ring 33 and a metal middle plate 34. There is. As a result, the cross-sectional shape of the seal S is formed into a C-shape that opens toward the pressure air chamber 7 side, and an annular hollow 1!5 is formed. The annular metal ring 33 has an inverted cross-sectional shape, and the middle plate 34 is formed in a U-shape that opens radially inward.

A rubber annular tension part 40 extending radially outward is formed integrally with the seal member 1 on the lip part 1a of the seal member 1 on the pressure air chamber 7 side, and the outer peripheral end of the tension part 40 is connected to the middle plate. It is sandwiched between the side bolt V part on the side of the pressure air chamber of 34 and the washer 41.
The outer peripheral end of is connected to the end of the reinforcing member 2 on the fE pressure air chamber 7 side.

A plurality of communication holes 44 are formed in the tension portion 40 to communicate the hollow chamber 5 and the pressurized air chamber 7.

The washer t/41 is the inward clutch portion 33a of the metal ring 33.
J:Relationship IF has been done. Reference numeral 46 denotes a sliding member made of Tefcon (trade name of polytetrafluorene resin manufactured by DuPont), and is fixed to the inner circumferential end surface of the sealing member 1. A spring 47 presses the sealing member toward the inner circumference.

The communication holes 44 of the tension portion 40 are formed in a circular shape as shown in FIG. 3, and are arranged at intervals in the circumferential direction.

Next, to explain the operation, when the engine is rotating, for example, when connecting the clutch, the second
The air of the air supply a30 in the figure is supplied to the control mechanism 29 and the pipe 2.
Pressure air is sent through chamber 7 between seals S through 8, and by 1
26 etc., the air pressure chamber 20 in the cylinder part 16 is supplied, and the brake lever 11-plate 19 is connected to the clutch disc 1.
2.

When the clutch is in the connected state, the pressure air chamber 7 between the seals S
The pressure of the first
The hollow chamber 5 in the seal S in the figure also has the same pressure, and due to the seal width W of the lip portion 1a of the seal member 1, F=PDπW
Tightening generates force. And tension part 4 at 111
Since a tensile force is generated at zero, the rate of increase in the tightening force F decreases as the pressure in the hollow chamber 5 increases. Therefore the lip is
1a can be suppressed to a low level.

(Another embodiment) (1) It is also possible to have a structure in which the seal member 1 is provided on the radially inner side and the reinforcing member 2 is provided on the inner side.

(2) The shape of the communication hole 44 is 3 as shown in FIG.
Various shapes such as a square shape or a fan shape as shown in FIG. 5 can be adopted.

(Effects of the Invention) As explained above, according to the present invention, the annular seal member 1
An annular tension part 40 is provided to connect the tip lip part 1a and the reinforcing member 2, and the annular tension part 40 is provided with a plurality of communication holes 44 that communicate the annular hollow chamber 5 and the pressure air chamber 7 in the seal. Since it is formed, it has the following advantages.

(1) Since the hollow chamber 5 and the pressure air chamber 7 are communicated with each other through the communication hole 44, the pressure required for sealing can be obtained from the pressure inside the hollow chamber 5, and the sealing performance is good.

(2) When the air pressure in the pressure air chamber 7 becomes higher due to the trend toward higher pressure and higher speed of air clutches, the tightening force of the lip portion 1a is reduced by the force F due to the tensile force of the tension portion 40.
This suppresses an excessive increase in ! in the lip portion 1a. +
)! The increase in heat generation can be suppressed to a small level. In other words, pressure resistance is improved and seal life is extended.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a seal to which the present invention is applied, FIG. 2 is a schematic cross-sectional view showing an example of an air clutch equipped with the seal of the present invention, FIG. , FIG. 5 shows a modification of the seal, and FIG. 6 is an enlarged sectional view of the conventional example. 1... Seal member, 2... Reinforcement member, 5...
Hollow chamber, 7... Pressure air chamber, 13... Input shaft (rotating member), 14... Bearing case (sealing M member), 4
0...Tension part, 44...Communication hole

Claims (1)

[Claims] The seal includes an annular seal member that contacts the rotating member and an annular reinforcing member that is fitted into the seal mounting member, and one end of the annular seal member in the axial direction and one end of the annular reinforcing member are connected. In a seal structure in which the cross-sectional shape is C-shaped and the annular hollow chamber within the seal is opened toward the pressure air chamber of the seal mounting member, the tip lip of the annular seal member and the other end of the reinforcing member are connected. 1. A seal structure characterized in that an annular tension portion is provided, and a plurality of communication holes are formed in the annular tension portion to communicate the hollow chamber and the pressure air chamber.