JPH11108202A - Labyrinth seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the length of a separate type labyrinth seal in the axial direction by devising the structure of a labyrinth part. SOLUTION: A separate type labyrinth seal comprises a stator 1 mounted on a bearing housing and a rotor 2 mounted on a shaft, the rotor 2 being separated from the stator 1 in the axial direction. A labyrinth part 5 is formed such that a part overlapped in the radial direction of the shaft between recesses/ protrusions along the axial direction of the stator 1 and recesses/protrusions along the axial direction of the rotor 2, is formed in two parts in the radial direction, and a plurality of circumferential grooves 8 around a shaft axis are made in parallel in the axial direction on the shaft-mounted part 16 of the rotor 2 facing the cutout of the stator 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a pump, a motor,
The present invention relates to a labyrinth seal for a bearing of a rotating machine such as a gear box, and more particularly, to a compact labyrinth seal of a separation type.

[0002]

2. Description of the Related Art Labyrinth seals are roughly classified into two types, an integrated type and a separated type. As the integrated type, the one disclosed in JP-A-9-177802 is known. That is, by forming each of the stator and the rotor by screwing two parts together, the stator and the rotor are integrated so that they cannot be separated from each other in an assembled state, and thus can be easily assembled into a machine. And so on.

On the other hand, as shown in FIG. 5, a separated type stator 1 is press-fitted into a housing 12.
And a rotor 2 fitted externally to the shaft 3 so as to be relatively slidable in the axial direction of the shaft, and is provided with a labyrinth 5 formed by radial irregularities. In this structure, the separated state in which the stator 1 and the rotor 2 are separated from each other in the axial direction can be freely changed from the sealing action state in which the stator 1 and the rotor 2 form a pair.

[0004]

Conventionally, the labyrinth portion of the above-mentioned separate type labyrinth seal has a structure in which, as shown in the drawing, irregularities in the radial direction of the shaft formed on the stator and the rotor are overlapped in the axial direction of the shaft. Was formed. Therefore, in order to ensure a sufficient sealing function,
If a plurality of overlapping portions of unevenness are formed by overlapping in the axial direction, the axial length of the seal tends to be long, and it may be difficult to use it depending on a machine using the seal. An object of the present invention is to reduce the axial length of the separation type labyrinth seal by devising the structure of the labyrinth part.

[0005]

[Means for Solving the Problems]

[Configuration] A first invention is a labyrinth seal comprising a stator mounted on a housing and a rotor externally fitted to a shaft which rotates relative to the housing, wherein the stator and the rotor are positioned relative to each other in the axial direction of the shaft. The stator and the rotor are configured to be relatively movable in the axial direction so that the stator and the rotor can be separated from the sealing action state in which the labyrinth portion is formed in the vicinity of the labyrinth portion. A labyrinth portion is formed by overlapping a plurality of portions in the radial direction of the shaft where the unevenness along the direction overlaps in the radial direction of the shaft.

According to a second aspect of the present invention, in the first aspect, the stator or the rotor at the portion where the stator and the rotor face each other in the axial direction in the sealing state are provided with a plurality of circumferential grooves around the shaft axis. It is characterized by being juxtaposed in the axial direction.

A third invention is characterized in that, in the second invention, a plurality of circumferential grooves are formed at locations other than the labyrinth portion.

According to the structure of the first aspect, a plurality of portions where the unevenness along the axial direction of the stator and the unevenness along the axial direction of the rotor overlap in the radial direction of the shaft are overlapped in the radial direction. Since the labyrinth portion is formed, the length of the labyrinth portion in the axial direction can be as short as one set of the overlapping of the unevenness of the stator and the rotor. Then, since the plurality of overlaps between the irregularities overlap in the radial direction, the labyrinth (maze) portion can be increased while maintaining the above-described short axial length, and the sealing function can be enhanced.

Further, since the stator and the rotor can be separated from each other by moving the stator and the rotor in the axial direction from the sealing operation state in which the sealing function is exhibited, cleaning and inspection between the stator and the rotor can be easily performed, and the stator or the rotor can be easily operated. It is also possible to exchange only one of them.

According to the configuration of the second aspect, in addition to the above operation, the following operation is provided. That is, since a plurality of circumferential grooves centered on the shaft axis are arranged in the axial direction on the stator or the rotor at the portion where the stator and the rotor face each other, a gap is provided between the rotating body and the stationary body. And the expansion chamber is repeatedly formed, whereby the pressure of the leaked fluid is changed to a speed, and the sealing function can be exhibited by generating a loss.

By the way, there is a structure in which a spiral groove is used as a screw groove to provide a sealing function by pressure loss while enabling the groove to be efficiently formed. In this structure, the stator and the rotor approach each other in the axial direction by rotation. Or an axial force is generated in the separating direction, so that there is a surface in which it is difficult to maintain the above-mentioned sealing operation state. On the other hand, in the means of the present application in which the circumferential grooves are arranged in the axial direction, no axial force is generated regardless of the rotation direction, so that the axial distance between the stator and the rotor during use is reduced. There is no danger of change, and the sealing state can be maintained satisfactorily.

According to the third aspect of the present invention, since the plurality of circumferential grooves are formed at locations other than the labyrinth portion, the sealing function by the labyrinth portion and the sealing function by the plurality of circumferential grooves are synergistic. And the leakage of the fluid is more effectively suppressed.

[Effect] In the labyrinth seal according to any one of claims 1 to 3, in a separation type advantageous for maintenance such as cleaning and replacement of parts, the labyrinth seal has a compact axial length while effectively exhibiting a sealing function. Because of this, it was possible to increase the range of adaptability to rotating machines, and improved versatility, for example, it could be used for models where installation space in the axial direction was difficult to obtain.

In the labyrinth seal according to the second aspect,
(A) The sealing function by the plurality of circumferential grooves is added, and the sealing function in the separation type can be strengthened while maintaining the normal sealing function state regardless of the presence or absence of rotation and its direction.

In the labyrinth seal according to the third aspect,
By making the labyrinth part and the plurality of circumferential groove parts independent, there is an advantage that the effect of (a) can be further reinforced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a state in which a labyrinth seal A is mounted on a rotating machine.
The stator 2 on the stationary side, which is fitted inside, is a rotor which is fitted on the shaft 3 and rotates integrally with the shaft 3, and has a bearing 4 disposed near the machine inside the stator 1 near the machine. The labyrinth seal A prevents leakage of lubricating oil from the inside of the machine to the outside, and prevents intrusion of water, dust and the like from the outside of the machine to the inside.

As shown in FIG. 2, the stator 1 and the rotor 2
From the sealing state in which the labyrinth portion 5 is formed by being disposed relatively close to each other in the axial direction of the shaft 3, the rotor 2 is moved relative to the stator 1 in the axial direction as shown by the phantom line in FIG. The rotor 1 and the rotor 2 are configured to be separable, and the rotor 2 can be removed from the stator 1.

The labyrinth portion 5 has a portion where the unevenness 6 along the axial direction of the stator 1 and the unevenness 7 along the axial direction of the rotor 2 overlap in the radial direction of the shaft 3 as shown in FIGS. A plurality of radial grooves 8 are formed so as to overlap with each other in the radial direction, and the stator 1 and the rotor 2 at the portion where the stator 1 and the rotor 2 face each other along the axial direction in the sealing action state. Are arranged side by side in the axial direction. Next, before detailing the structure in the sealing action state,
The shape of each component will be described.

As shown in FIG. 3, the stator 1 is composed of two sets of stator unevenness 6 including a concave groove 10 and a ridge 11 extending along the axial direction and a large-diameter outer periphery 9 which are formed in a radial direction. The narrow inner diameter portion 15 formed laterally (in the axial direction) of the press-fit portion 13 into the bearing housing 12 in the overlapped state and having the V-groove 14 opening toward the shaft 3 is formed inside the press-fit portion 13. It is formed at the back end and is formed with a cutout portion 17 into which the shaft mounting portion 16 of the rotor 2 is inserted and arranged. An O-ring 18 which is a seal functioning between the press-fitting portion 13 and the bearing housing 12 is provided at an intermediate portion in the axial direction. A hole 25 is formed in a side wall of the V groove 14 on the inner side of the press-fit portion 13.

As shown in FIG. 4, the rotor 2 has a stator unevenness 7 comprising a groove 19 and a ridge 20 extending along the axial direction.
Are formed on the outer diameter side of the shaft mounting portion 16 in a state of being overlapped in the radial direction, and a plurality of (five) circumferential grooves 8 are continuously formed on the outer peripheral surface of the shaft mounting portion 16. It is configured. Two O-rings 21, which are seals functioning between the shaft 3 and the shaft 3, are mounted on the inner peripheral surface of the shaft mounting portion 16 that protrudes in the axial direction while being spaced apart in the axial direction.
The adjacent circumferential grooves 8 are independent without interfering with each other, and do not generate an axial force due to the rotation of the shaft 3 like a spiral groove or a screw groove.

Again, as shown in FIG.
Is formed by fitting the concave groove 10 of the stator 1 and the convex line 20 of the rotor 2 and the convex line 11 of the stator 1 and the concave groove 19 of the rotor 2 respectively. Is located. If the axial gap is made larger than the radial gap between each of the concave grooves 10, 19 and each of the ridges 20, 11, an effective sealing action can be obtained by repeating the gap and the enlarged chamber.

The outer peripheral surface 16a of the shaft mounting portion 16 in which a plurality of parallel circumferential grooves 8 are formed and the flat inner peripheral surface 17a of the notch 17 on the stator 1 side are arranged to face each other. An effective sealing action is obtained by repeating the gap and the expansion chamber. And two O-rings 21,
The sealing action between the rotor 2 and the shaft 3 is strengthened by arranging the 21 in parallel. Also, between the narrow inner diameter portion 15 and the shaft 3, the gap and the enlarged chamber are alternately formed due to the presence of the V-shaped groove 14, so that the sealing action is generated. Furthermore, V
The lubricating oil can return to the rotating machine side from the hole 25 provided on the inner side wall of the press-fitting portion 13 of the groove 14, and the sealing action can be further enhanced.

In other words, since the labyrinth portion 5 and the circumferential groove 8 exhibiting the sealing function are arranged so as to overlap in the radial direction of the shaft, the axial length required for the labyrinth portion can be relatively short. While the labyrinth seal 1 and the rotor 2 are relatively slidable in the axial direction relative to each other, the axial length of the entire seal including the width of the press-fitting portion 13 has been made more compact than before. .

[Alternative Embodiment] A plurality of circumferential grooves 8 arranged in the axial direction may be formed on the ridges 11 of the stator 1 or the ridges 20 of the rotor 2. Part 17
May be formed on the inner peripheral surface 17a. Furthermore, shaft 3
May be applied and the labyrinth seal of the present application may be applied to a structure in which the bearing housing 12 rotates.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a use state of a labyrinth seal.

FIG. 2 is a sectional view of a main part showing a structure of a labyrinth seal.

FIG. 3 is a sectional view showing a shape of a stator.

FIG. 4 is a sectional view showing a shape of a rotor.

FIG. 5 is a sectional view of a main part showing a conventional separated labyrinth seal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 2 Rotor 3 Shaft 5 Labyrinth part 6 Stator unevenness 7 Rotor unevenness 8 Circumferential groove 12 Bearing housing P Shaft axis

Claims (3)

[Claims] 1. A labyrinth seal comprising a stator mounted on a housing and a rotor externally fitted on a shaft which rotates relative to the housing, wherein the stator and the rotor are positioned relative to each other in the axial direction of the shaft. From the sealing state in which the labyrinth portion is formed close to the stator, the stator and the rotor are configured to be relatively movable in the axial direction so that the stator and the rotor can be separated,
A labyrinth seal in which the labyrinth portion is formed by overlapping a plurality of portions in the radial direction of the shaft where the unevenness along the axial direction of the stator and the unevenness along the axial direction of the rotor overlap in the radial direction of the shaft. . 2. A plurality of circumferential grooves centered on a shaft axis are provided on the stator or the rotor at a portion where the stator and the rotor face each other along the axial direction in the sealing operation state. The labyrinth seal according to claim 1, wherein the labyrinth seal is arranged in a direction. 3. The labyrinth seal according to claim 2, wherein the plurality of circumferential grooves are formed at locations other than the labyrinth portion.