JPH0412276Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a mechanical seal that seals the rotating shaft of a machine body such as a water pump.

[Conventional technology] Conventionally, in this type of mechanical seal,
As shown in FIG. 3, a rotating shaft 4 is inserted through a mating ring 3 which is a fixed ring fixed to the housing 1 side of the machine body via a cup gasket 2.
As a means for elastically pressing the seal ring 5, which is a rotary ring that rotates together with the rotary shaft 4, into sliding contact with the mating ring 3, the seal ring 5 is usually attached to a rubber band that is in close contact with the rotary shaft 4. The bellows 6 is integrally constructed with a case 7 and a drive ring 8 which have a rotation prevention function on its outer periphery, and the mating Some devices have a structure in which the seal ring 5 is assembled by elastically pressing the ring 3, thereby preventing liquid leakage.

In the case of mechanical seals with this conventional structure, so-called rotary body mechanical seals,
The rubber bellows 6 is designed to have a cross-sectional shape with a bent portion 6a so as to withstand pressure from the back side, and as shown in FIG.
A tapered inner diameter space 51 is formed on the back surface of the seal ring 5 corresponding to the angle a, and a part of the bent portion 6a of the rubber bellows 6 is formed in this tapered inner diameter space 51 with a slight gap a. By facing the bent portion 6 of the seal ring 5 and rubber bellows 6.
A to a certain degree of freedom is provided between the rotary shaft 4 and the rotary shaft 4 to follow the reciprocating behavior in the axial direction of the rotary shaft 4 that occurs at the time of starting or stopping the operation.

[Problems to be solved by the invention] However, in the conventional mechanical seal described above, when the seal ring 5 is assembled to the rotating shaft 4, the gap between the sliding surface 5a of the seal ring 5 and the spring suppressing member 9 is Due to variations in the installation length L,
When the bent portion 6a of the rubber bellows 6 is assembled tightly into the tapered inner diameter space 51 of the seal ring 5, the seal ring 5 has almost no degree of freedom.
When the assembly load becomes significantly high and the sliding torque increases, not only is it easy to seize the sliding surface, damage the sliding material, or cause startup failure, but also when the behavior of the rotating shaft 4 is large. In this case, the behavioral force of the rotating shaft 4 exceeds the tightening force of the rubber bellows 6 to the rotating shaft 4, and the seal ring 5 is pushed back rearward. There was a problem in that the sliding surface with the ring 5 opened and the sealing fluid leaked.

[Purpose of the invention] The present invention was developed under the above circumstances, and its purpose is to increase the degree of freedom of the seal ring during assembly and to prevent the generation of excessive assembly loads. An object of the present invention is to provide a mechanical seal that can avoid influence on the behavior of a rotating shaft.

[Means for solving the problems] In order to solve the above problems, the present invention has the following features:
A rotating ring that rotates together with the rotating shaft is elastically pressed and urged into sliding contact with a fixed ring fixed to the housing side of the aircraft, and a case equipped with a rotation prevention function is provided on the back side of the rotating ring. A mechanical seal is provided with a rubber bellows for transmitting the rotation of the rotating shaft, and a part of the bent part of the rubber bellows faces a tapered inner diameter space formed on the back surface of the rotating ring. A ring-shaped inner diameter space along the axial direction is continuously formed in the tapered inner diameter space, and a space is provided between the bent portion of the rubber bellows and the tapered inner diameter space with a margin. It is.

[Operation] That is, in the present invention, by having the above-mentioned configuration, a ring-shaped inner diameter space along the axial direction is formed continuously with the tapered inner diameter space in the tapered inner diameter space of the rotating ring, Since there is a space between the bent part of the rubber bellows and the tapered inner diameter space, the degree of freedom of the seal ring can be increased, so when assembling the seal ring to the rotating shaft. Even if there is some variation in the installation length of the seal ring, the bent part of the rubber bellows will not be assembled tightly into the tapered inner diameter space of the seal ring, and this will prevent excessive installation load. It is possible to prevent seizure of the sliding surface, damage to the sliding material, or failure to start due to vibration, and even if the movement of the rotating shaft is large, the tightening force of the rubber bellows to the rotating shaft is higher than that of the rubber bellows. Since there is no rotation, the sliding surfaces between the mating ring and the seal ring do not open during operation, making it possible to maintain good sealing performance over a long period of time.

[Example] Hereinafter, the present invention will be described in detail with reference to an example shown in FIGS. 1 and 2. In the illustrated embodiment of the present invention, parts having the same structure as the conventional mechanical seal shown in FIGS. 3 and 4 will be described using the same reference numerals.

That is, as shown in FIG. 1, in the present invention, a ring-shaped inner diameter space 52 is continuously formed in the tapered inner diameter space 51 formed on the back surface of the seal ring 5 along the axial direction. Therefore, as shown in FIG. 2, when the rubber bellows 6 is assembled to the rotating shaft 4, the gap width W between the bent portion 6a of the rubber bellows 6 and the tapered inner diameter space 51 is made to have an allowance. It is structured as follows.

It should be noted that the present invention is not limited to the above-described embodiments in any way, and it goes without saying that various modifications can be made without changing the gist of the present invention.

[Effect of the invention] As is clear from the above explanation, according to the present invention, the fixed ring fixed to the housing side of the aircraft body has a
A rotating ring that rotates with the rotating shaft is elastically pressed and urged into sliding contact, and a rubber bellows is provided on the back side of the rotating ring to transmit the rotation of the rotating shaft via a case with a rotation stop function. In addition, in a mechanical seal in which a part of the bent portion of the rubber bellows faces a tapered inner diameter space formed on the back surface of the rotary ring, a ring-shaped part extends along the axial direction in the tapered inner diameter space of the rotary ring. The inner diameter space of the rubber bellows is formed continuously, and the gap between the bent part of the rubber bellows and the tapered inner diameter space is provided with a margin, so that the degree of freedom of the seal ring can be increased. Therefore, when assembling the seal ring onto the rotating shaft, even if there is some variation in the installation length of the seal ring, the bent part of the rubber bellows can be assembled in a tight state in the tapered inner diameter space of the seal ring. As a result, it is possible to prevent seizure of the sliding surface, damage to the sliding material, or startup failure due to excessive assembly loads, and also to prevent the occurrence of starting failures even if the behavior of the rotating shaft is large. Since the tightening force of the rubber bellows to the rotating shaft is never exceeded, the sliding surfaces of the mating ring and seal ring do not open during operation, and this ensures long-term operation. This has the excellent effect of maintaining good sealing performance.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part showing an embodiment of a seal ring used in a mechanical seal according to the present invention, Fig. 2 is a schematic sectional view of a main part showing the same mechanical seal, and Fig. 3 is a conventional mechanical seal. FIG. 4 is a schematic cross-sectional view of a main part showing a conventional seal ring. DESCRIPTION OF SYMBOLS 1... Body housing, 3... Fixed ring (mating ring), 4... Rotating shaft, 5... Rotating ring (seal ring), 51... Tapered inner diameter space,
52...Ring-shaped inner diameter space, 6...Rubber bellows, 6a...Bending portion, 10...Coil spring, W...Gap.

Claims (1)

[Scope of utility model registration request] A rotary ring that rotates with the rotary shaft is elastically pressed and urged into sliding contact with a fixed ring fixed to the housing side of the fuselage, and a case equipped with a rotation prevention function is provided on the back side of the rotary ring. A mechanical seal is provided with a rubber bellows for transmitting the rotation of the rotating shaft, and a part of the bent part of the rubber bellows faces a tapered inner diameter space formed on the back surface of the rotating ring. A ring-shaped inner diameter space along the axial direction is continuously formed in the tapered inner diameter space, and a space is provided between the bent portion of the rubber bellows and the tapered inner diameter space. mechanical seal.