JPS598450Y2 - Rotating shaft sealing device - Google Patents

Description

[Detailed description of the invention] This invention relates to a shaft sealing device for a rotating shaft, and in particular, liquid is introduced into the rotor through a supply port provided in the rotor from a supply port provided in the stationary housing to seal the rotor coil. Also, for example, an internal liquid cooling type generator, etc., in which a bearing is provided in the housing on the atmospheric pressure side and the stationary side, and a shaft sealing device between the bearing and the generator rotor is provided. The present invention relates to a shaft sealing device for a rotating shaft in a rotating electric machine.

Note that the housing does not necessarily need to be filled with liquid for cooling the rotor coil.

A conventional shaft sealing device for a rotating shaft of this type is shown in FIG.

In FIG. 1, threaded screws 2 are formed on a rotating shaft 1, and a threaded seal 5 is formed by these threaded screws 2 and the inner peripheral surface 4 of an integral annular stationary housing 3 surrounding the threaded screws 2. The threaded seal 5 separates one high-pressure liquid side A from the other atmospheric pressure side B in the axial direction.

This screw seal 5 works to push back the liquid leaking from the high pressure liquid side A to the atmospheric pressure side B by the pump action caused by the rotation of the rotating shaft 1, and the liquid pressure due to the pump action pushes back the liquid leaking from the high pressure liquid side A to the atmospheric pressure side B. When the hydraulic pressure is balanced, i.e.
After the rotating shaft 1 reaches a certain number of revolutions, leakage of liquid from this certain number of revolutions to the rated number of revolutions is prevented.

Therefore, with such a threaded seal 5, when the rotating shaft 1 is stopped or in a low rotation speed range until reaching a certain rotation speed,
For this reason, an elastic, integral annular thin film rubber 6 and a pressure chamber 7 are arranged around the outer circumference of the rubber are arranged on the circumferential surface of the rotating shaft 1 on the atmospheric pressure side B. By supplying high-pressure gas from the port 8, the thin film rubber 6 is bulged and deformed and pressed against the circumferential surface of the shaft, thereby preventing leakage of liquid below the above-mentioned constant rotation speed.

Furthermore, at a rotation speed above a certain number, the pressure in the pressure chamber 7 is reduced to separate the thin film rubber 6 from the shaft peripheral surface.

However, the shaft sealing effect due to the bulging deformation of the thin film rubber 6 is caused by the poor lubrication performance of the thin film rubber 6, and if the shaft is used for a long time during turning or in a low rotation speed range. This not only increases the amount of rubber abrasion and lowers the reliability of the seal, but also has disadvantages such as the need to control the gas pressure in order to expand and contract the seal.

This invention was made in order to improve the conventional inconvenience, and the sealing effect is obtained below a certain number of rotations until the screw seal exhibits the specified performance, and the sealing effect is obtained when the number of rotations exceeds a certain number. To provide a shaft sealing device for a rotating shaft that can automatically cancel the low-speed sealing action after the rotary shaft begins to perform the intended sealing action.

An embodiment of the shaft sealing device for a rotating shaft according to this invention will be described in detail below with reference to FIG. 2.

In Fig. 2, the same reference numerals as in Fig. 1 indicate corresponding parts; 9 is a rotating ring provided on the peripheral surface of the rotating shaft on the atmospheric pressure side; 9a is one end face of this rotating ring 9; 10 is a rotating ring. A fixed cylinder concentric with the shaft 1, 11 a stop ring provided on the fixed cylinder 10, 12 a sliding ring fitted onto the fixed cylinder 10, 12a,
Reference numeral 12b represents an end face of the sliding ring 12, and reference numeral 13 represents a spring that presses the end face 12a of the sliding ring 12 against the end face 9a of the rotary ring 9 by its elastic force.

In this embodiment, a rotating ring 9 is formed on the circumferential surface of the atmospheric pressure side B of the rotating shaft 1, and a stop ring 11 is provided at the protruding end toward one end surface 9a of the rotating ring 9. A fixed cylinder 10 having a fixed cylinder 10 is provided concentrically with the rotating shaft 1 and protrudes from the housing 3, and an end face 12a of a sliding ring 12 is fitted onto the fixed cylinder 10 so as to be slidable in the axial direction, and one end is attached to the housing 3. a spring 13 whose other end is attached to the end surface 12b of the sliding ring 12;
The rotating shaft may be brought into pressure contact with the end surface 9a by the elastic force of In response to the axial elongation of the rotating shaft 1 shown by the arrow C due to the temperature rise, the end surface 9 of the rotating ring 9
a and the end face 12a of the sliding ring 12 can be separated from each other.

In the figure, 14 is an O-ring.

Therefore, in the structure of this embodiment, when the rotary shaft 1 is stopped or rotates at low speed, the shaft temperature is low and the axial elongation in the direction of arrow C is small, so the sliding ring 12 is closed to the stop ring 11 as shown in the figure. The end surface 12a is pressed against the end surface 9a of the rotating ring 9 by the elastic force of the spring 13 without colliding with the end surface 12a, thereby sealing the liquid from the high-pressure liquid side A. From this state, the rotating shaft 1 As the rotational speed gradually increases and approaches the above-mentioned constant rotational speed, the axial elongation in the direction of arrow C also gradually increases, so the position of the rotating ring 9 moves in the direction of arrow C, causing sliding. The ring 12 also moves following this.

When the rotating shaft 1 reaches a certain rotation speed, the front edge of the sliding ring 12 hits the stop ring 11 and is stopped, thereby preventing the sliding ring 12 from moving in the direction of the rotating ring 9. Therefore, from now on, the two end surfaces 9a and 12a, which had been pressed together, are separated, and the sealing effect for low rotation, which was exerted by the pressure contact of these two end surfaces 9a and 12a, is released. Instead, the screw seal 5 that has reached a certain number of rotations performs a sealing action for high rotation, and thereafter this screw seal 5 prevents liquid leakage from the high-pressure liquid side A.

Here, in the above embodiment, the case where the axial elongation of the rotating shaft 1 due to temperature rise is in the direction of the arrow C is explained as an example. If the axial extension of the rotating shaft 1 occurs in the direction opposite to the arrow C, the sliding ring 12 may be brought into pressure contact with the end surface 9a from the opposite side, thereby obtaining the same effect. I can do it.

As described in detail above, according to this invention, in a rotating shaft in which a threaded screw formed on the shaft is brought close to the inner circumferential surface of the housing to form a threaded seal, the threaded screw on the shaft circumferential surface on the atmospheric pressure side of the rotating shaft is At the same time, a rotating ring is provided on the fixed cylinder concentric with the rotating shaft, and an axial direction The end faces of the slidably inserted sliding ring are brought into pressure contact, and a stop ring provided on the fixed cylinder is used to stop the sliding ring at a position where the rotating shaft reaches a certain rotational speed and reaches a certain amount of extension.
Since the pressure contact between the end faces is released, the pressure contact between the end face of the sliding ring and the end face of the rotating ring on the circumferential surface of the rotating shaft prevents the screw seal from performing its sealing function when stopped or below a certain rotation speed. In addition to being able to perform sealing, once the threaded seal reaches a certain number of revolutions at which it performs its sealing action, the sealing action can be canceled below a certain number of revolutions due to the axial expansion caused by the temperature rise of the shaft itself. Moreover, it has the advantage of automatically performing this operation without any external control, and its mechanism is also simple, easy to implement, and can be implemented at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a conventional shaft sealing device for a rotating shaft, and FIG. 2 is a sectional view showing an embodiment of the shaft sealing device for a rotating shaft according to this invention. 1...Rotating shaft, 2...Threaded screw, 3...Housing, 4...Inner peripheral surface of housing, 5...Thread seal , 9...
・Rotating ring, 9a...End face of rotating ring, 10...
... Fixed cylinder, 11 ... Stop ring, 12 ...
... Sliding ring, 12a, 12b... End face of sliding ring, 13... Spring.

Claims (1)

[Scope of utility model registration request] In rotating electric machines such as internal liquid-cooled generators, which have a threaded seal for high-speed rotation that obtains a sealing effect above a certain number of rotations by a threaded screw formed on the shaft and an integral annular stationary housing surrounding it. In the shaft sealing device for a rotating shaft, a rotating ring is provided on the circumferential surface of the rotating shaft on the atmospheric pressure side, which is the high pressure liquid side and the atmospheric pressure side separated by the threaded seal, and a rotating ring is provided on the circumferential surface of the rotating shaft on the atmospheric pressure side, which is separated by the threaded seal, and a The end face of a sliding ring fitted on a fixed cylinder concentric with the rotating shaft is brought into pressure contact with the end face of the rotating ring to provide an end face seal for stopping and low speed rotation that obtains a sealing effect below a certain number of rotations, and the above-mentioned The movable range of the sliding ring in the axial direction is limited by a stop ring provided on the fixed cylinder, so that sliding pressure welding can be stopped at the axially extending position of the rotating shaft when a certain number of rotations has been reached. A shaft sealing device for the rotating shaft.