JPH0126932Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a mechanical seal used as a shaft sealing device for a rotating shaft. The purpose is to improve the sealing performance and durability of the mechanical seal provided.

[Conventional technology]

Conventionally, as shown in FIG. 6, a mechanical seal has a fixed ring 1 and a rotating ring 2, and seals the fluid to be sealed by close sliding between the two rings 1 and 2. It is commonly used that a substantially L-shaped metal case 4 is externally fitted and the rotational driving force of the rotating shaft 3 is transmitted to the rotating ring 2 via the case 4. In this type of mechanical seal, the driving force is transmitted from the case 4 to the rotating ring 2 through engagement notches 5 formed at equal intervals on the outer peripheral surface of the rotating ring 2 and cut in the same direction as the axis, and the case 4. This is done by engaging with engaging claws 6 which are equally spaced and protruding from each other and extend in the same direction as the shaft. That is, as shown in FIG. 7, when the case 4 rotates in the direction of the arrow in the figure, the engagement claws 6,
A side portion 6' formed linearly in a direction parallel to the axis,
Abutting against the rising surface 5' of the corresponding engagement notch 5,
The rotary ring 2 is rotated by pressing.

Generally, in order to prevent leakage of sealed fluid when a mechanical seal is stopped, it is effective to increase the adhesion force between the fixed ring 1 and the rotating ring 2 by increasing the assembly load of the mechanical seal. It has become a means.

[Problem that the invention attempts to solve]

However, if the assembly load is increased, the amount of heat generated by sliding during rotational driving will increase, and the amount of wear on the sliding surfaces will increase. No measures have been taken to reduce the load on the surface, so increasing the load will lead to an early decline in seal durability, and reducing the load will lead to an increase in leakage during shutdown. It was hot.

[Means for solving problems]

In view of the above problems, the present invention aims to provide a mechanical seal with a structure that reduces the load applied to the sliding surface during rotation, and reduces the shaft driving force.
In a mechanical seal that transmits information to a rotating ring that is loosely fitted onto the shaft via a case that is fitted onto the shaft, the periphery of a required number of engagement notches extending in the axial direction is provided on the outer peripheral surface of the rotating ring. The rising surface is inclined with respect to the axial direction so that the directional width becomes larger toward the sliding surface side, and the circumferential width of the engagement claws protruding in the axial direction from the outer periphery of the case is set at the tip. The side surface is inclined with respect to the axial direction so that the side surface becomes larger toward the top, and the angle of inclination of the side surface coincides with the angle of inclination of the rising surface.

[Effect]

When the case is rotationally driven together with the rotating shaft, one side of the engaging claw protruding from the case comes into contact with one rising surface of the engaging notch of the rotating ring and transmits the rotational driving force to the rotating ring. The side surface of the engaging claw is inclined with respect to the axial direction so that the circumferential width thereof becomes larger at the tip side, and the rising surface of the engaging notch opposite to the side surface is also an inclined surface that coincides with the side surface. Therefore, the input direction of the driving force from the engaging claw that is perpendicular to the rising surface is inclined toward the rear side of the rotating ring with respect to the circumferential direction, and the axial direction thereof is The force acts to relieve the load on the sliding surface of the mechanical seal.

〔Example〕

Hereinafter, a preferred embodiment of the mechanical seal of the present invention will be described in detail based on the drawings.

FIG. 1 is a front view showing this embodiment, in which reference numeral 11 indicates a fixed ring fitted and fixed to the inner periphery of the housing 12 via an O-ring 13, and 14 indicates a metal case 16 fitted externally to the rotating shaft 15. The rotary ring receives the rotational driving force of the rotary shaft 15 through the rotary shaft 15, and slides on the fixed ring 11 by being pressed by the elastic force of a contracted coil spring 17 whose rear end is supported by the metal case 16. be. Engagement notches 18 are formed on the outer circumferential surface of the rotating ring 14 so as to be equally spaced in the circumferential direction, and the rising surfaces 18a and 18b are equal to the circumferential width W of the engagement notches 18.
1 is inclined with respect to the axial direction so that it becomes larger on the sliding surface side of the rotating ring 14. Further, an engaging pawl 19 is provided on the outer peripheral edge of the metal case 16 at a position corresponding to the engaging notch 18 and protrudes in the axial direction, and engages with the engaging notch 18 in the circumferential direction. Both side surfaces 19a and 19b are inclined with respect to the axial direction so that the circumferential width W2 of the engaging claw 19 becomes larger on the tip side, and the angle of inclination is equal to the rising surface 18 of the engaging notch 18.
It matches the inclination angle of a and 18b (15°, see Figure 2).

According to the above configuration, for example, when the rotating shaft 15 rotates in the direction of arrow A in the figure, the metal case 16 rotates accordingly, and as shown in FIG.
One side surface 19b of the engaging claw 19 protruding from the rotating ring 14 contacts one rising surface 18b of the engaging notch 18 formed in the rotating ring 14, and transmits the driving force of the rotating shaft 15. The driving force is applied to the rising surface 18b as a force F in a direction perpendicular to the rotating ring 1.
4 in the direction of arrow A in FIG. Since the coil spring 17 acts in the opposite direction to the pressing direction of the coil spring 17, the load on the rotating ring 14 due to the coil spring 17 is alleviated. The axial component force f1 is proportional to the magnitude of the force F, and when the vehicle is stopped, the axial component force f1 becomes zero, and the load of the coil spring 17 on the rotating ring 14 increases.

Next, Figures 3 to 5 all show the results of a comparative test of the mechanical seal according to this example with a conventional example. First, Figure 3 shows the following results: Rotation speed: 5500rpm Rotational pressure: 12Kg/ cm ² G Liquid to be sealed: Suniso 5GS + Freon R-12 Time: Graph showing the sliding surface temperature measurement results under the conditions of 200Hrs. Figure 4 is an enlarged cross section showing the wear condition of the sliding surface of the fixed ring after the above test. Figure 5 is a graph showing the leakage amount measurement results under the following conditions: Number of revolutions: 2000 rpm Pressure during rotation: 8 Kg/cm ² G Pressure at stop: 5 Kg/cm ² G Liquid to be sealed: Suniso 5GS + Freon R-12 .

[Effect of idea]

As is clear from the above test results, the mechanical seal of the present invention has a structure that reduces the load applied to the sliding surface during rotation, which reduces the amount of heat generated by sliding and suppresses wear on the sliding surface. In addition to improving the seal durability, the assembly load can be set larger than before, so leakage during stoppage can be reduced, among other effects.

[Brief explanation of drawings]

Fig. 1 is a front view showing one embodiment of the mechanical seal of the present invention, Fig. 2 is a front view of the main parts, Fig. 3 is a graph showing the test results, and Fig. 4 shows the wear condition of the fixed ring sliding surface. FIG. 5 is a graph showing the test results, FIG. 6 is a half-cut sectional view of a conventional mechanical seal, and FIG. 7 is a front view of the same main part. 11...Fixed ring, 12...Housing, 13...
...O-ring, 14... Rotating ring, 15... Rotating shaft,
16...Metal case, 17...Coil spring, 18...Engagement notch, 18a, 18b...Rising surface, 19...Engagement claw, 19a, 19b...Side surface.

Claims (1)

[Scope of utility model registration request] In a mechanical seal that is used as a shaft sealing device for a rotating shaft and transmits shaft driving force to a rotating ring that is loosely fitted onto the shaft through a case that is fitted onto the shaft, the outer circumferential surface of the rotating ring is The rising surface of the engagement notches provided in a required number extending in the axial direction is inclined with respect to the axial direction so that the width in the circumferential direction becomes larger toward the sliding surface side, and The side surfaces of the engagement claws provided in a required number are inclined with respect to the axial direction so that the width in the circumferential direction increases toward the tip, and the angle of inclination of the side surfaces matches the angle of inclination of the rising surface. A mechanical seal characterized by being configured to.