JP2021116917A - Seal device - Google Patents

Abstract

To position a shaft core of a lip part relative to a shaft core of a shaft during operation more accurately in a contact type seal device including the lip part.SOLUTION: A seal device is disposed enclosing a shaft S and restricts flow of a liquid in a direction along a shaft core of the shaft S. The seal device comprises: a casing 2 which includes an insertion hole 2a into which the shaft S is inserted; an annular seal ring 3 which includes a lip part 3b capable of sliding on a peripheral surface of the shaft S and which is placed in slide contact with the casing 2; and a disc spring 4 which biases the seal ring 3 to the casing 2 in a direction along the shaft core.SELECTED DRAWING: Figure 2

Description

The present invention relates to a sealing device.

Conventionally, a floating sealing device has been known as a non-contact sealing device having no contact portion with respect to the shaft. In such a floating sealing device, the sealing ring is movable in the radial direction, and the sealing property is exhibited by holding the shaft and the sealing ring at an extremely small separation distance and a constant separation distance in the circumferential direction. However, since such a non-contact sealing device is not in contact with the shaft, the sealing property is lower than that of the contact type sealing device. Therefore, when high sealing performance is required, a contact-type sealing device including a lip portion that is slidably contacted with the shaft is generally used (see Patent Document 1 and Patent Document 2).

Japanese Unexamined Patent Publication No. 2011-241886 Japanese Unexamined Patent Publication No. 2015-155739

For example, a turbo pump used in a rocket engine or the like is required to have high sealing performance. Therefore, a contact-type sealing device having a high sealing property is often used. However, in the above turbo pumps and the like, extremely low temperature liquid oxygen and liquid hydrogen may be sealed around a shaft rotating at high speed (for example, 40,000 rpm). In the sealing device used in such an extreme environment of extremely low temperature and high peripheral speed, a resin lip portion is used in order to improve the sealing property. Since the resin lip portion has a larger coefficient of linear expansion than the metal that forms the shaft, it contracts at an extremely low temperature and is strongly pressed against the peripheral surface of the shaft, whereby high sealing performance can be exhibited.

On the other hand, since the resin lip portion as described above is designed to be pressed against the shaft with an appropriate force when contracting at an extremely low temperature, the lip portion is designed to be pressed against the shaft in a high temperature environment such as room temperature. Is inflated to a state where it is separated from the peripheral surface of the shaft. Therefore, when assembling the sealing device, it is difficult to accurately align the shaft core of the annular lip portion with the shaft core of the shaft. If the shaft core of the lip portion and the shaft core of the shaft are slightly misaligned, a stress biased in the circumferential direction acts on the lip portion during operation, which shortens the life of the sealing device and seals. The time to replace the device will be earlier.

It should be noted that such a problem is not limited to the sealing device used at an extremely low temperature. Even if the seal device is not used at extremely low temperatures, if the position of the axis of the lip is deviated from the axis of the shaft, the life of the lip will be shortened, and similarly, it is time to replace the seal. Will be hastened.

The present invention has been made in view of the above-mentioned problems, and in a contact-type sealing device provided with a lip portion, it is possible to more accurately align the shaft core of the lip portion with respect to the shaft core during operation. The purpose is to do.

The present invention employs the following configuration as a means for solving the above problems.

The first invention is a sealing device which is arranged around a shaft and regulates the flow of liquid in a direction along the axis of the shaft, and has a casing having an insertion hole through which the shaft is inserted. An annular seal ring having a rubbable lip portion on the peripheral surface of the shaft and slidably contacting the casing, and the seal ring in a direction along the axis of the seal ring. A configuration is adopted in which an urging portion for urging the casing is provided.

In the second invention, in the first invention, the seal ring is arranged on the outer side of the annular lip portion and the lip portion in the radial direction of the seal ring, and the lip portion is provided on the inner peripheral surface. A configuration is adopted in which the casing is connected and has an annular ring portion having a sliding surface that is slidably contacted with the casing.

In the third invention, in the second invention, the lip portion is extended inward in the radial direction from the inner peripheral surface of the ring portion, and the tip thereof is oriented in the direction along the axis. Adopt a configuration that is curved to.

The fourth invention adopts the configuration in which the tip of the lip portion is located inside the end face of the ring portion in the direction along the axis in the third invention.

In the fifth aspect of the invention, in any one of the second to fourth inventions, the casing has a liquid inflow space outside the ring portion in the radial direction through which the liquid can flow, and is inside the ring portion. A configuration is adopted in which a low-pressure fluid contact surface is provided on the peripheral surface so that a fluid having a lower pressure than the liquid flowing into the liquid inflow space can come into contact with the peripheral surface.

A sixth aspect of the present invention is the annular protrusion in which the casing projects in the direction along the axis and the tip surface is pressed against the sliding surface of the ring portion in any one of the second to fifth inventions. Adopt the configuration of having.

According to the present invention, the seal ring having the lip portion is not fixed to the casing and is slidable in the radial direction with respect to the casing. Therefore, the seal ring is automatically moved so as to align the shaft core with the shaft core by the reaction force received from the shaft. That is, according to the present invention, even if the axis of the lip portion is deviated from the axis of the shaft at the time of attachment, the lip portion is automatically centered by rotating the shaft. Therefore, according to the present invention, it is possible to more accurately align the axis of the lip portion with respect to the axis of the shaft during operation.

It is sectional drawing which shows typically the schematic structure of the sealing device in one Embodiment of this invention. It is an enlarged view of the main part which enlarged a part of the sealing device in one Embodiment of this invention. It is a schematic diagram which shows the pressure state around the seal ring provided in the seal device in one Embodiment of this invention.

Hereinafter, an embodiment of the sealing device according to the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing a schematic configuration of the sealing device 1 of the present embodiment. The sealing device 1 of the present embodiment is arranged so as to surround the shaft S from the outside in the radial direction, and regulates the flow of liquid in the direction along the axis of the shaft S. In the present embodiment, the sealing device 1 regulates the flow of liquid from the high pressure side (left side of the sealing device 1 in FIG. 1) to the low pressure side (right side of the sealing device 1 in FIG. 1). As shown in FIG. 1, the sealing device 1 of the present embodiment includes a casing 2, a sealing ring 3, and a disc spring 4 (biased portion).

The casing 2 is a member that houses the seal ring 3 and the disc spring 4. As shown in FIG. 1, the casing 2 has an insertion hole 2a through which the shaft S is inserted. The diameter dimension of the insertion hole 2a is set to be larger than the diameter dimension of the shaft S. Therefore, as shown in FIG. 1, a certain gap is formed between the inner wall surface of the insertion hole 2a and the peripheral surface of the shaft S.

FIG. 2 is an enlarged view of a main part of the sealing device 1 in which a part of the sealing device 1 is enlarged. As shown in this figure, the casing 2 is provided with a liquid inflow space 2b for allowing the liquid on the high pressure side to flow in. The liquid inflow space 2b is formed by a groove portion that is recessed from the inner peripheral surface of the insertion hole 2a of the casing 2 toward the outside in the radial direction of the casing 2. The liquid inflow space 2b is continuously provided in an annular shape about the shaft core when viewed from the direction along the shaft core of the casing 2 (that is, the shaft core of the shaft S).

As shown in FIG. 2, such a liquid inflow space 2b accommodates a part of the seal ring 3 and the disc spring 4. In such a liquid inflow space 2b, the depth dimension in the radial direction is located on the outer side in the radial direction with respect to the outer peripheral surface of the seal ring 3 so that the high-pressure liquid flows to the outside in the radial direction of the seal ring 3. It is set. Therefore, a certain gap is provided between the outer peripheral surface of the seal ring 3 and the inner peripheral surface of the liquid inflow space 2b (the bottom surface of the groove-shaped liquid inflow space 2b). The seal ring 3 can be moved in the radial direction by such a gap. As will be described in more detail later, in the present embodiment, the seal ring 3 is slidably contacted with the casing 2. That is, in the present embodiment, the seal ring 3 is slidably contacted with the casing 2.

Further, as shown in FIG. 2, the casing 2 has an annular protrusion 2c protruding from the inner wall surface of the liquid inflow space 2b in the direction along the axis. The annular protrusion 2c is located near the low pressure side (right side in FIG. 2) of the liquid inflow space 2b, and is located on the high pressure side from the most shaft S side (inside in the radial direction) of the inner wall surface orthogonal to the axis L. It is provided so as to project toward (the left side in FIG. 2). The tip surface of such an annular protrusion 2c is slidably pressed against the ring portion 3a described later of the seal ring 3.

The seal ring 3 has a ring portion 3a and a lip portion 3b, and these ring portions 3a and the lip portion 3b are integrated. The seal ring 3 is entirely made of resin. The seal ring 3 has an annular shape centered on a common shaft core L of the ring portion 3a and the lip portion 3b.

As shown in FIG. 2, the ring portion 3a is a block-shaped member having a rectangular cross section and an annular shape when viewed from the direction along the axis L, and is a radial direction of the lip portion 3b. It is located on the outside of. In the ring portion 3a, the shaft S is inserted through a circular opening provided in the central portion when viewed from the direction along the axis L. The diameter dimension of the opening at the center is set to be larger than the diameter of the shaft S. Therefore, a gap is provided between the inner peripheral surface of the ring portion 3a and the outer peripheral surface of the shaft S.

One of the two surfaces of the ring portion 3a orthogonal to the axis L (the surface located on the right side of FIG. 2) is a contact surface with the annular protrusion 2c of the casing 2. The ring portion 3a is movable in the radial direction. That is, in the present embodiment, the contact surface of the ring portion 3a with the annular protrusion 2c is a sliding surface with the casing 2. On the other hand, one of the two surfaces of the ring portion 3a orthogonal to the axis L (the surface located on the left side of FIG. 2) is a contact surface with the disc spring 4.

The lip portion 3b is a portion that can be rubbed on the peripheral surface of the shaft S, and is arranged inside the ring portion 3a in the radial direction. The lip portion 3b is continuously provided in an annular shape when viewed from the direction along the axis L, and projects inward in the radial direction from the inner peripheral surface of the opening of the ring portion 3a. Further, as shown in FIG. 2, the lip portion 3b is extended inward in the radial direction from the inner peripheral surface (inner peripheral surface of the central opening) of the ring portion 3a, and the tip thereof is in the direction along the axis L. It is curved so that it faces. That is, in the present embodiment, the root portion of the lip portion 3b is connected to the inner peripheral surface of the ring portion 3a from the radial direction, and the tip of the lip portion 3b is directed in the direction (high pressure side) along the axis L. ..

Further, the lip portion 3b is connected to the central portion of the ring portion 3a in the direction along the axis L. By rubbing the lip portion 3b against the peripheral surface of the shaft S, the flow of the liquid from the high pressure side to the low pressure side is restricted. Therefore, the high-pressure liquid comes into contact with the region of the inner peripheral surface of the ring portion 3a on the high-pressure side of the lip portion 3b, and the region of the inner peripheral surface of the ring portion 3a on the low-pressure side of the lip portion 3b Low pressure liquids come into contact. That is, in the present embodiment, as shown in FIG. 2, a low-pressure fluid capable of contacting the inner peripheral surface of the ring portion 3a with a liquid (fluid) having a lower pressure than the liquid (high-pressure liquid) flowing into the liquid inflow space 2b. The contact surface 3a1 is provided.

The tip of the lip portion 3b is located inside the end surface (contact surface with the disc spring 4) of the ring portion 3a in the direction along the axis L. For example, when the seal ring 3 is formed by carving from a resin block body, if the tip of the lip portion 3b protrudes from the ring portion 3a in the direction along the axis L, the lip portion 3b It becomes necessary to scrape a large number of parts corresponding to the ring portion 3a having a larger volume than that of the ring portion 3a, resulting in waste of material. On the other hand, when the tip of the lip portion 3b is located inside the end surface of the ring portion 3a as in the present embodiment, the length of the lip portion 3b is adjusted to the length in the direction along the axis L. It is not necessary to scrape the ring portion 3a, and waste of material can be reduced.

It should be noted that such a lip portion 3b is curved as described above even in a state where no external force is applied. That is, the lip portion 3b is curved even when the reaction force from the shaft S is not received.

The disc spring 4 is inserted between the liquid inflow space 2b and the seal ring 3, and urges the seal ring 3 toward the annular protrusion 2c of the casing 2. The seal ring 3 is pressed against the casing 2 by the urging force of the disc spring 4. As shown in FIG. 2, the disc spring 4 is in contact with the ring portion 3a of the seal ring 3.

The disc spring 4 has an annular shape when viewed from the direction along the axis L. Further, the disc spring 4 is provided with a plurality of discrete openings when viewed from the direction along the shaft core L, so that liquid can pass between the front side and the back side of the disc spring 4. ..

According to the sealing device 1 of the present embodiment having such a configuration, the lip portion 3b is rubbed against the peripheral surface of the shaft S and the ring portion 3a is pressed against the annular protrusion 2c of the casing 2 to obtain a high pressure. The liquid is sealed so that it does not flow to the low pressure side. Here, when the sealing device 1 is attached, even if the shaft core L of the sealing device 1 is displaced with respect to the shaft core of the shaft S, the lip portion 3b receives the lip portion 3b when it comes into contact with the shaft S. Due to the reaction force, the shaft core L of the lip portion 3b is automatically matched with the shaft core of the shaft S.

The sealing device 1 of the present embodiment as described above is arranged so as to surround the shaft S and regulates the flow of the liquid on the shaft S in the direction along the axis. The sealing device 1 of the present embodiment has a casing 2 having an insertion hole 2a through which the shaft S is inserted, and a rubbable lip portion 3b on the peripheral surface of the shaft S, and is slidable with respect to the casing 2. An annular seal ring 3 to be abutted and a disc spring 4 for urging the seal ring 3 toward the casing 2 in a direction along the shaft core L are provided.

According to the sealing device 1 of the present embodiment as described above, the sealing ring 3 having the lip portion 3b is not fixed to the casing 2 and is slidable in the radial direction with respect to the casing 2. Therefore, the seal ring 3 is automatically moved so as to align the shaft core L with the shaft core of the shaft S by the reaction force received from the shaft S. That is, according to the sealing device 1 of the present embodiment, the sealing ring 3 shrinks in a low temperature environment even when the shaft core L of the lip portion 3b is deviated from the shaft core of the shaft S at the time of mounting. In addition, the lip portion 3b is automatically centered by the reaction force received by the rotation of the shaft S. Therefore, according to the sealing device 1 of the present embodiment, it is possible to more accurately align the shaft core L of the lip portion 3b with respect to the shaft core of the shaft S during operation.

Further, in the sealing device 1 of the present embodiment, the sealing ring 3 is arranged outside the annular lip portion 3b and the lip portion 3b in the radial direction of the sealing ring 3, and the lip portion 3b is connected to the inner peripheral surface. In addition, it has an annular ring portion 3a having a sliding surface that is slidably contacted with the casing 2. Therefore, the portion slidable with respect to the casing 2 can be separated from the lip portion 3b, and the lip portion 3b is not slid on the casing 2. Therefore, it is possible to prevent the lip portion 3b from being unintentionally deformed or the like due to sliding with the casing 2.

Further, in the sealing device 1 of the present embodiment, the lip portion 3b is extended inward in the radial direction from the inner peripheral surface of the ring portion 3a, and the tip is curved so as to face the direction along the axis L. ing. Therefore, as compared with the case where the tip of the lip portion 3b is brought into contact with the peripheral surface of the shaft S without bending the lip portion 3b, the contact area between the lip portion 3b and the shaft S is increased to improve the sealing property. It becomes possible.

Further, in the sealing device 1 of the present embodiment, the tip of the lip portion 3b is located inside the end surface of the ring portion 3a in the direction along the axis L. Therefore, when the seal ring 3 is formed by cutting out, the waste of the material can be reduced as described above.

Further, in the sealing device 1 of the present embodiment, the casing 2 has a liquid inflow space 2b through which liquid can flow in outside the ring portion 3a in the radial direction, and a liquid inflow space is provided on the inner peripheral surface of the ring portion 3a. A low-pressure fluid contact surface 3a1 is provided so that a fluid having a lower pressure than the liquid flowing into 2b can come into contact with the liquid. FIG. 3 is a schematic view showing a pressure state around the seal ring 3. The disc spring 4 is omitted in FIG. As shown in FIG. 3, the high-pressure region R1 having a relatively high pressure is formed so as to cover the entire outer peripheral surface of the ring portion 3a. On the other hand, the low pressure region R2 having a relatively low pressure is in contact with the low pressure fluid contact surface 3a1 which is a part of the inner peripheral surface of the ring portion 3a. Therefore, as shown by the arrow in FIG. 3, a force acts on the ring portion 3a (that is, the seal ring 3) inward in the radial direction. Therefore, the lip portion 3b can be strongly pressed against the shaft S, and the sealing property can be improved.

Further, in the sealing device 1 of the present embodiment, the casing 2 has an annular protrusion 2c that protrudes in the direction along the axis L and whose tip surface is pressed against the sliding surface of the ring portion 3a. Therefore, as compared with the case where the casing 2 is in pressure contact with the ring portion 3a over a wide area, the surface pressure in the contact region can be increased, and the sealing property can be improved.

Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above embodiment. The various shapes and combinations of the constituent members shown in the above-described embodiment are examples, and can be variously changed based on design requirements and the like without departing from the spirit of the present invention.

For example, in the above embodiment, the configuration in which the seal ring 3 is provided with only one lip portion 3b has been described. However, the present invention is not limited to this. For example, it is possible to adopt a configuration in which a plurality of lip portions 3b are provided in a direction along the axis L.

Further, in the above embodiment, the configuration in which the lip portion 3b is connected to the central position of the ring portion 3a in the direction along the axis L has been described. However, the present invention is not limited to this. For example, the lip portion 3b may be connected to the lowest pressure side of the inner peripheral surface of the ring portion 3a. In such a case, the low-pressure fluid contact surface 3a1 is not provided.

Further, in the above embodiment, the configuration in which the disc spring 4 is used as the urging portion has been described. However, the present invention is not limited to this, and other elastic members can be used as the urging portion.

1 ... Sealing device, 2 ... Casing, 2a ... Insertion hole, 2b ... Liquid inflow space, 2c ... Circular protrusion, 3 ... Seal ring, 3a ... Ring part, 3a1 ... Low pressure fluid contact surface 3, 3b …… Lip part, 4 …… Belleville spring (biased part), L …… Shaft core, S …… Shaft

Claims (6)

A sealing device that is arranged around the shaft and regulates the flow of liquid in the direction along the axis of the shaft.
A casing having an insertion hole through which the shaft is inserted, and
An annular seal ring having a rubbable lip portion on the peripheral surface of the shaft and slidably contacting the casing.
A sealing device comprising: an urging portion for urging the sealing ring toward the casing in a direction along the axis of the sealing ring. The seal ring is
The annular lip portion and
An annular shape that is arranged outside the lip portion in the radial direction of the seal ring, the lip portion is connected to the inner peripheral surface, and has a sliding surface that is slidably abutted against the casing. The sealing device according to claim 1, further comprising a ring portion. 2. The lip portion is characterized in that the lip portion is extended inward in the radial direction from the inner peripheral surface of the ring portion and the tip is curved so as to face a direction along the axis. The sealing device described. The sealing device according to claim 3, wherein the tip of the lip portion is located inside the end surface of the ring portion in a direction along the axis. The casing has a liquid inflow space in which the liquid can flow in outside the ring portion in the radial direction.
2. The sealing device described. The casing according to any one of claims 2 to 5, wherein the casing projects in a direction along the axis and has an annular protrusion whose tip surface is in pressure contact with the sliding surface of the ring portion. Sealing device.

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