WO2012096057A1

WO2012096057A1 - Dual-shaft rotor pump

Info

Publication number: WO2012096057A1
Application number: PCT/JP2011/076849
Authority: WO
Inventors: 志郎谷川
Original assignee: アネスト岩田株式会社
Priority date: 2011-01-11
Filing date: 2011-11-22
Publication date: 2012-07-19
Also published as: JP5389833B2; JP2012145017A

Abstract

A dual-shaft rotor pump having a casing, two rotary shafts provided within the casing, two rotors provided respectively on the two rotary shafts and capable of rotating in mutually opposing directions, and shaft bearings and shaft seals provided on each of the two rotary shafts, with the two rotors working together to compress and discharge a fluid within the casing, wherein a connecting passage is provided connecting the interior of the casing and each of the aforementioned shaft bearings, and the open end on the casing-interior side of the connecting passage is provided at a location where it is opened/closed by the rotation of the rotors such that the connecting passage is open during at least part of the fluid compression period.

Description

2-axis rotor pump

The present invention relates to a biaxial rotor pump, and particularly relates to a shaft seal in a mechanical dry vacuum pump or the like called a roots type, a screw type, a claw type or the like having a biaxial rotating shaft. The present invention relates to a twin-shaft rotor pump that can reduce the pressure load (differential pressure) and extend the life of the shaft seal.

As a fluid pump such as a vacuum pump, for example, a root type in which a plurality of vertical rotors (rotors) rotate at high speed in a casing to discharge air, and a plurality of screw (screw) type rotors while rotating with a casing A pump having a biaxial rotating shaft, such as a screw type that compresses and discharges air confined in between, and a claw type in which a rotor having a projection similar to a claw rotates in a casing to discharge air Are known.

Among such two-shaft rotor pumps having two rotating shafts, for example, a claw-type pump generally has two rotors having one or two claw-shaped protrusions, and each rotor has It is attached to each of two other shafts. The two rotors are arranged so as to engage with each other when the two shafts rotate in opposite directions, and are housed in a casing provided with a suction port and a discharge port. The two shafts that support the two rotors are provided with bearings and shaft seals, respectively.

In such a claw type biaxial rotor pump, the fluid sucked into the casing is sucked into the casing through the suction port. Then, a fixed volume of fluid is captured and compressed between the claw-like projections of the two rotors (hereinafter referred to as a compression chamber), and the compressed fluid is discharged from the discharge port.
Such a claw-type two-shaft rotor pump is disclosed in, for example, Patent Document 1 and is generally used.

JP-A-6-101673

By the way, for example, in the claw type, screw type, roots type and other biaxial rotor pumps as described above, in order to always maintain the rotational phase (synchronization) and center of each axis accurately, it is generally made of metal. The gear is used. This metal gear can transmit the driving force while maintaining accurate synchronization as long as the teeth are not damaged. However, since wear occurs, lubrication using a lubricating material such as oil, grease, or solid lubricant is necessary.

In the two-shaft rotor pump, a ball bearing is generally used as a bearing. For this reason, a shaft seal is provided between the rotor and the ball bearing. This shaft seal serves to prevent the leakage of the lubricating material used in the bearing, such as grease and lubricating oil, and the lubricating material used in the gears described above, to the compression chamber and to receive differential pressure between the compression chamber and the bearing. Plays.

However, in such a two-shaft rotor pump, the pressure load received by the shaft seal is high, so that there is a possibility that the life of the shaft seal will be reduced and the lubricating material may leak into the compression chamber due to the differential pressure.

Therefore, by providing a flow path that always communicates the bearing and the compression chamber, the pressure difference between the bearing and the compression chamber is eliminated by the action of the flow path, and the shaft seal leaks into the compression chamber. Such a technique has already been realized.

However, when a flow path in which the bearing and the compression chamber are always in communication is provided, the pressure load on the shaft seal is reduced, but leakage of the lubricating material to the compression chamber due to the reciprocating movement of the fluid in the flow path is reduced. There is a possibility that this will occur, and power loss will occur due to wasteful fluid movement in the flow path.

Therefore, in view of the problems of the prior art, the present invention provides a casing, two rotating shafts provided in the casing, two rotors attached to the two rotating shafts and rotatable, and the two rotating shafts. A pressure load applied to the shaft seal in a two-shaft rotor pump having a bearing and a shaft seal provided on each rotary shaft, wherein the two rotors cooperate to compress and discharge the fluid in the casing It is an object of the present invention to provide a two-shaft rotor pump that can extend the life of the shaft seal by reducing the above and prevent generation of power loss due to wasteful fluid movement.

In order to solve the above problems, in the present invention, a casing, two rotating shafts provided in the casing, and two rotors attached to the two rotating shafts and capable of rotating in opposite directions to each other. And a bearing and shaft seal provided on each of the two rotating shafts, and the two rotors cooperate to compress and discharge the fluid in the casing. A communication passage that communicates the inside and the bearing is provided, and the open end inside the casing of the communication passage is at a position that is opened and closed by the rotation of the rotor so that the release timing is at least part of the fluid compression period. It is provided.

As a result, a portion (compression chamber) that performs compression in the casing formed by the rotor is communicated during a part of the compression period, so that the differential pressure between the compression chamber and the bearing is reduced, and the pressure of the shaft seal is reduced. The load is reduced and the life of the shaft seal can be extended.

Furthermore, since the communication path is not always open and is opened only during compression, the fluid can be prevented from reciprocating in the communication path, and power loss due to wasteful fluid movement can be prevented. it can. At the same time, the bearing lubricant can be prevented from flowing into the compression chamber due to the reciprocating movement of the fluid in the communication path.

Further, the communication path may include a communication groove that communicates between the bearings provided on each of the two rotating shafts, and a communication hole that communicates the inside of the communication groove and the inside of the casing.
Thereby, a part of communication path required for each of the two can be shared, and the invention can be implemented with a simple configuration.

Moreover, the casing additional member united with the casing is provided in the casing lower part, and the said communication groove is good to be provided in the said casing additional member.
This makes it easier to implement the present invention by modifying a conventional claw-type biaxial rotor pump that does not have a communication groove.

Moreover, the casing inner side open end of the said communicating path is good to be provided in the position where the ratio of the pressure of the said compressed fluid and the said bearing becomes 1.2 or less during the compression period of the said fluid.
Thereby, the lifetime improvement of a shaft seal can be achieved reliably.

According to the present invention, the casing, the two rotary shafts provided in the casing, the two rotors attached to the two rotary shafts and rotatable, and the two rotary shafts are provided. A two-shaft rotor pump having a bearing and a shaft seal, wherein the two rotors cooperate to compress and discharge the fluid in the casing, thereby reducing the pressure load on the shaft seal and reducing the shaft seal. It is possible to provide a two-shaft rotor pump capable of extending life and preventing generation of power loss due to wasteful fluid movement.

It is a cross-sectional view which passes along the compression chamber of the claw type biaxial rotor pump which concerns on an Example. FIG. 2 is a cross-sectional view passing through a compression chamber of a claw-type biaxial rotor pump in a state where the rotor in FIG. FIG. 2 is a cross-sectional view passing through a compression chamber of a claw-type biaxial rotor pump in a state where the rotor in FIG. FIG. 2 is a cross-sectional view taken along line bb in FIG. FIG. 2 is a cross-sectional view taken along the line aa in FIG.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

The configuration of the claw-type biaxial rotor pump according to the embodiment will be described with reference to FIGS. 1, 4, and 5.
FIG. 1 is a cross-sectional view passing through a compression chamber of a claw-type biaxial rotor pump according to an embodiment. 4 is a cross-sectional view taken along the line bb in FIG. 1, and FIG. 5 is a cross-sectional view taken along the line aa in FIG. In FIG. 4, a state where a communication hole 30 described later is closed by the rotor 6 is shown.

The claw type biaxial rotor pump 1 according to the embodiment is provided with two

shafts

2 and 4. A rotor 6 having claw-

like protrusions

10a and 10b is attached to the shaft 2 at two locations. Similarly, a rotor 8 having claw-

like projections

12a and 12b at two locations is attached to the shaft 4. Is attached. The

shafts

2 and 4 and the

rotors

6 and 8 are accommodated in the casing 14.

The shaft 2 is housed in the casing 14 and is rotatably supported by the casing 14 by a plurality of bearings 24. Similarly, the shaft 4 is also housed in the casing 14 and supported by the casing 14 so as to be rotatable in the direction opposite to the shaft 2 by a plurality of bearings (not shown but referred to as bearings 44 for convenience). A shaft seal 26 is provided between the bearing 24 and the rotor 6. Similarly, a shaft seal (not shown, but referred to as a shaft seal 46 for convenience) is provided between the bearing 44 and the rotor 8. As the shaft seals 26 and 46, for example, an oil seal or a labyrinth seal can be applied.

With such a configuration, in the claw-type biaxial rotor pump 1 shown in FIG. 1, the

rotors

6 and 8 cooperate with the shaft 2 and the shaft 4 by driving means (not shown) when the pump 1 is used. By rotating in the reverse direction, it rotates in the directions indicated by arrows A and B in the chamber 16 formed in the casing 14, respectively. Due to the rotation and the configuration of the chamber 16 and the

rotors

4 and 6, a compression chamber 22 is formed between the

rotors

4 and 6 and the chamber wall surface 16a. The form of the compression chamber 22 varies depending on the rotation of the

rotors

4 and 6.

In FIG. 1, reference numeral 18 denotes a suction port provided on the lower surface of the casing 14, and sucks a fluid to be compressed from the outside into the chamber 16 from the outside. Reference numeral 20 denotes a suction port provided on the upper surface of the casing 14. This is a discharge port for discharging the compressed fluid upward. The suction port 18 and the discharge port 20 are opened and closed by the rotor 4 and the rotor 6 as the rotor 4 and the rotor 6 rotate.

As a characteristic configuration of the present invention, a communication groove 28 is provided below the bearing 24.
The communication groove 28 communicates between the bearing 24 and the bearing 44. Furthermore, a communication hole 30 is provided for communicating between the chamber 16 formed in the casing 14 and the communication groove 28. The opening surface of the communication hole 30 to the chamber 16 is provided at a position that is opened and closed by the rotor 6 as the rotor 6 rotates.

In addition, as shown in FIG. 4, the casing additional member 14a integrated with the casing 14 can be provided in the lower part of the casing 14, and the communication groove | channel 28 can also be provided in the casing additional member 14a. In this case, it becomes easy to implement the present invention by remodeling a claw type biaxial rotor pump that does not have the communication groove 28.

That is, the communication groove 28 and the communication hole 30 form a communication path between the chamber 16 and the bearing 24, and the communication path is opened and closed by the rotation of the rotor 6. Similarly, the communication groove 28 and the communication hole 30 form a communication path between the chamber 16 and the bearing 44, and the communication path is opened and closed by the rotation of the rotor 6. That is, the state where the compression chamber 22 formed in the chamber 16 and the bearing 24 and the bearing 44 can communicate with each other by the rotation of the rotor 6 is switched.

In the present embodiment, the communication groove 28 communicates the bearing 24 and the bearing 44, and the communication passage between the bearings 24 and 44 and the chamber 16 is formed by providing one communication hole 30, Other forms may be used as long as communication paths are provided between the respective bearings 24, 44 and the chamber 16 and the communication paths are opened and closed by the rotation of the rotor 6. For example, a first communication path that communicates between the bearing 24 and the chamber 16 and a second communication path that communicates between the bearing 44 and the chamber 16 may be provided separately.

In the claw-type biaxial rotor pump 1 having the above-described configuration, the

rotors

4 and 6 attached to the two

shafts

2 and 4 rotate in opposite directions to capture the fluid to be compressed sucked from the suction port 18. And compress. Specifically, while the

rotors

4 and 6 make one rotation, the rotor 4 and the rotor 6 open only the suction port 18 and the fluid is sucked into the compression chamber 22 formed in the chamber 16. Both the suction port 18 and the discharge port 20 are closed and the fluid is compressed, and then only the discharge port 20 is opened and the compressed fluid is discharged. By repeating the above operation, the fluid that is continuously sucked can be compressed. In FIG. 1, the portion indicated by 22a in the compression chamber 22 is a portion where both the supply port 18 and the discharge port 20 are closed and the fluid is compressed. Further, in FIG. 1, the portion indicated by 22 b in the compression chamber 22 is a portion where only the supply port 18 is opened and fluid is supplied.

Next, the operation of the communication groove 28 and the communication hole 30 during the operation of the claw type biaxial rotor pump 1 will be described.
FIG. 2 is a cross-sectional view through the compression chamber of the claw-type biaxial rotor pump in a state where the

rotors

4 and 6 in FIG. 1 are rotated by about 20 °. FIG. 3 is a cross-sectional view passing through the compression chamber of the claw-type biaxial rotor pump in a state where the

rotors

4 and 6 in FIG. 1 are rotated by about 45 °.

1 to 3, the portion indicated by 22a in the compression chamber 22 is a portion related to compression. The portion is referred to as the compression chamber 22a, and the portion of the compression chamber 22a will be described.
The fluid supplied from the supply port 18 first moves to the compression chamber 22a, which is a portion where the supply port 18 is closed by the rotation of the

rotors

4 and 6. At this time, the communication hole 30 is closed by the rotor 6.

Then, when the

rotor

4 and 6 are rotated and the position of the rotor 6 is moved to a position shifted from the upper end of the communication hole 30 as shown in FIG. The bearing 24 and the bearing 44 communicate with each other.
Then, the rotation of the rotor 4 and the rotor 6 continues, and the state where the communication hole 30 is opened as shown in FIG. 2 continues.
When the rotor 4 and the rotor 6 further rotate, the position of the rotor 6 moves to a position where the communication hole 30 is closed as shown in FIG.
Thereafter, the rotation of the rotor 4 and the rotor 6 further opens the compression chamber 22 a to the discharge port 20, and the fluid is discharged from the discharge port 20.

That is, while the fluid is compressed in the compression chamber 22a, the communication hole 30 is opened and closed in the order of closing → opening → closing. That is, during compression of the fluid, the compression chamber 22a and the bearings 24 and 44 are communicated only during a part of the period.

According to the present invention, since the compression chamber 22a and the bearings 24 and 44 are communicated with each other during a part of the compression, the differential pressure between the compression chamber 22a and the bearings 24 and 44 is reduced, and the shaft seals 26 and 46 The pressure load is reduced, and the life of the shaft seals 26 and 46 can be extended.
Furthermore, the communication path formed by the communication groove 28 and the communication hole 30 is not always opened, and is opened only at the time of compression. It is possible to prevent the occurrence of power loss due to. At the same time, the bearing lubricant can be prevented from flowing into the compression chamber due to the reciprocating movement of the fluid in the communication path.
In order to prolong the service life of the shaft seal 26, the position of the open portion 32 of the communication hole 30 is preferably provided at a position where the pressure ratio between the compression chamber 22a and the bearings 24 and 44 is about 1.2 or less.

In the present embodiment, the claw type biaxial rotor pump has been described. However, the present invention can be similarly applied to a root type, a screw type, and other biaxial rotor pumps.

A casing, two rotating shafts provided in the casing, two rotors attached to the two rotating shafts and rotatable, and bearings and shaft seals provided on the two rotating shafts, respectively. And a two-shaft rotor pump in which the two rotors cooperate to compress and discharge the fluid in the casing, thereby reducing the pressure load on the shaft seal and extending the life of the shaft seal. In addition, it can be used as a two-shaft rotor pump that can prevent the occurrence of power loss due to wasteful fluid movement.

Claims

A casing, two rotating shafts provided in the casing, two rotors attached to the two rotating shafts and capable of rotating in opposite directions, a bearing provided on each of the two rotating shafts, and A two-shaft rotor pump having a shaft seal, wherein the two rotors cooperate to compress and discharge the fluid in the casing;
Providing a communication path for communicating the inside of the casing and each of the bearings;
The open end inside the casing of the communication path is provided at a position that opens and closes by the rotation of the rotor so that the opening timing is at least part of the fluid compression period. .
The communication path includes a communication groove that communicates between the bearings provided on each of the two rotating shafts;
2. The twin-shaft rotor pump according to claim 1, wherein the two-shaft rotor pump includes a communication hole that communicates the inside of the communication groove and the inside of the casing.
In the lower part of the casing, a casing additional member integrated with the casing is provided,
The biaxial rotor pump according to claim 2, wherein the communication groove is provided in the casing additional member.
The casing inner open end of the communication path is provided at a position where a ratio of pressure between the compressed fluid and the bearing is 1.2 or less during a compression period of the fluid. Item 4. The biaxial rotor pump according to any one of Items 1 to 3.