WO2011049362A2

WO2011049362A2 - Screw rotor type vacuum pump incorporating motor

Info

Publication number: WO2011049362A2
Application number: PCT/KR2010/007189
Authority: WO
Inventors: 이헌
Original assignee: (주)코디박
Priority date: 2009-10-21
Filing date: 2010-10-20
Publication date: 2011-04-28
Also published as: WO2011049362A3; JP2013507575A; KR20110043331A; KR101138389B1

Abstract

The present invention relates to a screw rotor type vacuum pump incorporating a driving motor in any one of the pair of screw rotors, wherein the deformation of rotation balance may be reduced when the pair of screw rotors rotates. According to the present invention, provided is a screw rotor type vacuum pump comprising: a pair of screw rotors of which rotates and is to be engaged with each other; a housing for receiving the pair of screw rotors and having a suction hole at one side and a discharge hole at the other side; and a motor incorporated in any one of the pair of screw rotors for driving the rotation shaft thereof.

Description

Screw rotor type vacuum pump with built-in motor

The present invention relates to a screw rotor type vacuum pump in which a motor for driving is built into one of the screw rotors of the pair of screw rotors, and the deformation of the rotational balance during rotation of the pair of screw rotors can be reduced. It's about technology.

A vacuum means a space where no substance exists, but in reality, since it is difficult to make it, it refers to a low pressure of about 1/1000 mmHg or less. The pressure of the gas remaining in the container made of vacuum is called the degree of vacuum at that time, and the degree of vacuum is expressed by using the pressure of air at low pressure.

It prevents corrosive oxidation due to the influence of other bodies through the vacuum state, lowers the breaking point of materials, enables the transport of objects that are difficult to carry by other devices, and air molecule collisions such as protons. This makes it easier to control during operation.

At present, the maximum degree of vacuum that can be reached artificially is about 10 ^-12 mmHg, and there are about 35,000 gas molecules per cubic centimeter. However, the semiconductor manufacturing process and the display panel manufacturing process requires high vacuum, and various technologies are currently being developed to maintain the vacuum efficiently.

However, there are many problems to overcome in the conventional vacuum pump. In particular, in the case of an external motor of a screw rotor type vacuum pump, the motor and the screw rotor are combined with a coupling or similar parts to rotate. At this time, due to the gap tolerance due to the coupling or the center of the motor and the rotating body is not located in a straight line, the balance of the rotating body may be unbalanced, or may cause vibration.

Due to the problem that the rotation balance is not matched, heat may be generated due to the motor overload, and there is a risk of damage to the vacuum pump due to friction between the rotor and the housing. In addition, the loss of rotational force may cause a decrease in pumping capacity, a problem in the durability of the bearing may be a cause of frequent failures, excessive noise during operation may be a problem in the working environment.

The present invention for solving these problems, a screw that can reduce the deformation of the rotational balance during the rotation of a pair of screw rotor by embedding a motor for driving in any one of the screw rotor of the pair of screw rotor It is to provide a rotor type vacuum pump.

According to the present invention for achieving the above object, a pair of screw rotor that rotates in engagement with each other; A housing accommodating the pair of screw rotors, one side of which is provided with a suction port and the other side of which a discharge port is provided; And a motor built in the screw rotor of any one of the pair of screw rotors to drive the rotating shaft. There is provided a screw rotor type vacuum pump comprising a.

The centrifugal pump provided on the pair of screw rotor rotation shafts, preferably, the centrifugal pump includes an oil supply passage that extends through the center of the rotation shaft to the holes formed on both sides of the outer circumferential surface of the rotation shaft.

In the pair of screw rotors, a non-contact seal for non-contact sealing between the rotation shaft and the motor fixing member is interposed, and the inner diameter of the non-contact seal is preferably larger than the outer diameter of the rotation shaft.

A sealing gas supply passage is provided inside the motor fixing member so as to pass through the motor fixing member and the non-contact seal, and sealing gas is supplied to a gap between the inner circumferential surface of the non-contact seal and the outer circumferential surface of the rotary shaft to seal the gas. .

The inside of the motor fixing member, a sealing gas discharge passage is provided so that the sealing gas supplied into the gap between the inner peripheral surface of the non-contact seal and the outer peripheral surface of the rotary shaft can be discharged.

It is preferable that a sealing ring is provided between the inner circumferential surface of the motor fixing member and the outer circumferential surface of the non-contact seal so as to prevent leakage of the sealing gas from above and below the sealing gas supply passage.

It is preferable that the lead angle of the screw thread formed on the pair of screw rotor outer peripheral surfaces continuously changes.

It is preferable that the threads formed on the outer circumferential surfaces of the pair of screw rotors are continuously connected along the back lead section (a), the uneven lead section (b), and the back lead section (c).

It is preferable that the outer diameter of any one of the pair of screw rotors is larger than the outer diameter of the other screw rotors.

It is preferable that a motor is installed inside the screw rotor having a large outer diameter.

According to the present invention as described above, the screw rotor type vacuum which can minimize the deformation of the rotational balance during rotation of the pair of screw rotors by embedding a motor for driving in any one of the screw rotors of the pair of screw rotors Pumps may be provided.

Accordingly, according to the present invention, the imbalance problem of the rotational balance is reduced, so that the pumping for the vacuum can be efficiently performed at a high rotational force.

1 is a cross-sectional view of a built-in screw rotor type vacuum pump according to the present invention.

Figure 2 is a conceptual diagram for explaining the operation principle of the centrifugal pump according to the present invention.

3 is a conceptual diagram illustrating a non-contact sealing according to the present invention.

Figure 4 is a cross-sectional view of the screw rotor included in the screw rotor type vacuum pump according to an embodiment of the present invention.

5 is a cross-sectional view of the screw rotor included in the screw rotor type vacuum pump according to another embodiment of the present invention.

1: centrifugal pump 3: bearing

4a: rotor 4b: stator

4: motor 11: rotary shaft

12: Motor fixing member 13: Non-contact seal

14: sealing gas supply passage 15: sealing gas discharge passage

16: Oil supply passage 17: Sealing ring

21: inlet 22: discharge outlet

25: female screw rotor 26: male screw rotor

27: housing 28: operating room

Hereinafter, a screw rotor type vacuum pump having a motor built-in structure according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.

1 is a cross-sectional view of the built-in screw rotor type vacuum pump according to the present invention, Figure 2 is a conceptual diagram for explaining the operation principle of the centrifugal pump according to the present invention and in Figure 3 non-contact sealing according to the present invention A conceptual diagram is shown to illustrate. Figure 4 is a cross-sectional view of the screw rotor included in the screw rotor type vacuum pump according to an embodiment of the present invention is shown in Figure 5 of the screw rotor included in the screw rotor type vacuum pump according to another embodiment of the present invention A cross section is shown.

As shown in FIG. 1, a vacuum pump according to an embodiment of the present invention includes a male screw rotor 26 and a female screw rotor 25 capable of compressing and transporting gases, and a housing 27 surrounding them externally. It includes. The motor 4 is provided in order to rotate the

rotors

25 and 26 inside any one of the pair of screw rotors. On the rotating shaft 11 of each

rotor

25, 26 there is a bearing 3 for supporting it. Below the

rotors

25 and 26 there is a timing gear 2 which allows the rotary shaft of the male screw rotor 26 and the female screw rotor 25 to rotate in synchronization with each other.

The motor 4 consists of a rotor 4a and a stator 4b. The rotor 4a surrounds the rotating shaft 11 connected to the screw rotor to rotate the rotating shaft 11, and the stator 4b is surrounded by the motor fixing member 12 installed in the housing 27.

According to one embodiment of the present invention, by rotating the rotor 4a integrally with the screw rotor, it is possible to reduce the deformation of the rotational balance. In addition, the motor 4 may be present inside the screw rotor, thereby miniaturizing the pump. Preferably, the motor 4 may be mounted inside the male screw rotor 26. This is because the outer diameter of the male screw rotor 26 is generally larger than the outer diameter of the female screw rotor 25, so that a larger driving force can be obtained.

As shown in Figures 1 to 3, the centrifugal pump (1) provided in the pair of screw rotor shaft is formed in the lower end of the thin tube, such as a capillary tube in contact with the oil. The centrifugal pump includes an oil supply passage that passes through the center of the rotating shaft and continues to a hole formed at both sides of the outer circumferential surface of the rotating shaft. At this time, the oil rises into the vacuum pump as shown by the arrow through the oil supply passage 16, and the oil acting as a lubricant to the bearing 3 is supplied by the centrifugal force to achieve a smooth operation. In this case, since the oil may move into the shaft through the oil supply passage 16, the oil may directly cool the shaft.

As shown in FIG. 3, a non-contact seal 13 is interposed between the rotation shaft 11 and the motor fixing member 12. In order to seal the non-contact type, the inner diameter of the non-contact seal 13 is preferably larger than the outer diameter of the rotary shaft 11. The motor fixing member 12 includes a sealing gas supply passage 14 and a sealing gas discharge passage 15 through which the sealing gas may move.

In the gap formed between the inner diameter of the non-contact seal 13 and the outer diameter of the rotary shaft 11, sealing gas may be sealed up and down as the arrow direction is supplied through the sealing gas supply passage 14. In this case, a sealing ring 17 may be provided between the inner circumferential surface of the motor fixing member 13 and the outer circumferential surface of the non-contact seal so as not to leak the sealing gas.

By the non-contact sealing method as described above, when oil is supplied to the bearing through the oil supply passage 16 in the direction of the arrow, it is possible to prevent the oil is gasified outflow. In addition, since the non-contact seal 13 rotates in contact with the rotary shaft 11, wear, noise, dust, etc. due to physical friction may not occur, and the use of gas for shaft sealing may be minimized.

As shown in FIG. 4, the motor-mounted screw rotor type vacuum pump according to an embodiment of the present invention includes a male screw rotor 26 and a female screw rotor 25 and a housing 27 accommodating these rotors. An operating chamber 28 is formed. The operating chamber 28 includes a suction port 21 connected to one side of the operating chamber and a discharge port 22 connected to the other side of the operating chamber. In addition, the thread formed on the outer circumferential surface of the screw rotor may be in the form of an uneven interval in which the lead angle is continuously changed. Here, the lead angle is an angle formed by the screw rotor and the thread, as shown in FIG. 4.

The male screw rotor 26 and the female screw rotor 25 inside the working chamber 28 perform compression conveyance of gas in the direction of the arrow. Preferably, the outer diameter of the male screw rotor 26 is larger than the outer diameter of the female screw rotor 25. This is because due to the difference in the rotational speed due to the difference in the outer diameter, it is possible to suppress the phenomenon that the process by-products accumulate due to the frictional force of the contact portion between the male screw rotor 26 and the female screw rotor 25.

Under the operating chamber 28, the housing end face plate 24 is formed to be inclined in the form of gradually narrowing the cross sectional area in the direction of the discharge port 22, and has a cross section between the housing end face plate 24 and the

screw rotors

25 and 26. There is a gap 23. Due to the inclined shape of the housing end face plate 24, the gas from the

screw rotors

25 and 26 can be efficiently discharged toward the discharge port 22, and at the same time, the gas can be prevented from being despread.

In addition, by using the male screw rotor 26 and the female screw rotor 25 having leads that are continuously changed at different intervals, the lead angle gradually decreases from the inlet to the outlet. Therefore, the volume formed by the thread in the operating chamber 28 becomes smaller as it approaches the discharge port 22, so that the discharge pressure at the discharge port 22 increases and the flow of gas rapidly increases toward the discharge port 22. Will increase. Therefore, it is possible to smoothly discharge the gas to prevent overheating of the discharge port 22 side can be a vacuum pump of a thermally stable structure.

However, as shown in FIG. 5, according to another embodiment of the present invention, the thread formed on the outer circumferential surface of the screw rotor is continuously along the back lead section (a), the uneven lead section (b), and the back lead section (c). May be connected. Hereinafter, the same components as those in FIG. 4 are given the same reference numerals, and detailed descriptions thereof will be omitted.

The shape of the thread in each section is the back lead section (a) is

, The unequal lead interval (b)

, And the lead section (c)

Follow the shape of the graph represented by.

The a ₁ value of the back lead section a is determined by the ratio of the height of the screw rotor that satisfies the proper pump capacity calculated by the lead value (circumference) and the volume of the screw groove by the diameter when the screw rotor rotates. C ₁ is a range that can eliminate the overlap between each other caused by the difference in diameter between the male and female screw rotors. In the case of the male screw rotors, the value is “0”. It has a calculated value in the resolution range.

The a ₃ value of the back lead section c has the same meaning as the a1 value of the back lead section a, and c ₃ is determined by the height of the back lead section a and the uneven lead section b.

In the uneven lead section (b)

The slope obtained by differentiating is equal to a _1, a ₃ . a1 is the inclination of the point where the back lead section a and the inequality lead section b meet, and a3 is the inclination of the point where the uneven lead section b meets the back lead section a. Through this, it has a force function curve that connects the thread of the back lead section (a) and the thread of the back lead section (c). Further _, the curve is completed by obtaining a _2, b _{2, and} c ₂ values that simultaneously satisfy the minimum height value of the uneven lead section b obtained by volume calculation.

Hereinafter, the operation of the motor-built screw rotor type vacuum pump according to the present invention configured as described above will be described.

As shown in FIG. 1, when a motor 4 mounted in one of the pair of

screw rotors

25 and 26 is driven, the rotating shaft connected to the motor 4 rotates, and the timing The pair of

screw rotors

25 and 26 are rotated by the gear 2 synchronizing the rotary shaft of the male screw rotor with the rotary shaft of the female screw rotor.

As shown in FIG. 2, the centrifugal pump also rotates due to the rotation of the screw rotor. The centrifugal force generated by the screw rotor rotates along the oil supply passage 16 of the centrifugal pump as shown in the arrow direction of FIG. 3. Supplied. Therefore, smooth rotation of the motor can be achieved.

The sealing gas moves to the motor fixing member 12 surrounding the outer circumference of the non-contact seal 13 and the bearing 3 via the sealing gas supply passage 16. The moved sealing gas is supplied in the gap formed between the inner circumferential surface of the non-contact seal and the outer circumferential surface of the rotating shaft 11 in the direction of the arrow, and some sealing gas moves downward through the sealing gas discharge passage 15 in the direction of the arrow.

When the sealing gas is supplied to the gap formed between the inner circumferential surface of the non-contact seal and the outer circumferential surface of the rotating shaft 11 as shown in the direction of the arrow, complete sealing is performed, and the oil supplied to the bearing 3 is gasified and discharged into the vacuum pump. It can be prevented at the source.

The rotation of the pair of

screw rotors

25 and 26 sucks gas from the inlet 21 and simultaneously traps the sucked gas in the operating chamber 28. The sucked gas trapped in the operation chamber 28 is compressed and transported by the continuous rotation of the screw rotor to be discharged to the discharge port 22, resulting in high vacuum.

As described above, according to the structure of the vacuum pump with a built-in motor of the present invention, the deformation of the rotational balance during rotation of the screw rotor can be minimized by embedding the motor inside the screw rotor. In addition, since the space occupied when the motor is externally installed, it can be miniaturized than the existing pump of the same capacity, so the utilization of the work space is high.

In addition, by using the vacuum pump according to the present invention, the centrifugal pump is mounted inside the shaft of the screw rotor to smooth the lubrication of the bearing and move the oil into the shaft so that the shaft can be directly cooled to have an excellent cooling effect.

As described above, the motor-built screw rotor type vacuum pump according to the present invention has been described with reference to a preferred embodiment of the present invention. However, the present invention is not limited to the embodiments and drawings described above, and various modifications and changes may be made by those skilled in the art within the scope of the claims.

Claims

A pair of screw rotors engaged with each other and rotating;

A housing accommodating the pair of screw rotors, one side of which is provided with a suction port and the other side of which a discharge port is provided; And

A motor built in one of the screw rotors of the pair of screw rotors for driving the rotating shaft; Screw rotor type vacuum pump comprising a.
The method according to claim 1,

As a centrifugal pump provided in the pair of screw rotor rotation shaft,

The centrifugal pump is a screw rotor type vacuum pump, characterized in that it comprises an oil supply passage passing through the center of the rotating shaft to the holes formed on both sides of the outer peripheral surface of the rotating shaft.
The method according to claim 1,

In the pair of screw rotor, a non-contact seal for non-contact sealing between the rotating shaft and the motor fixing member is interposed,

The inner diameter of the non-contact seal is a screw rotor type vacuum pump, characterized in that larger than the outer diameter of the rotating shaft.
The method according to claim 3,

A sealing gas supply passage is provided inside the motor fixing member to penetrate the motor fixing member and the non-contact seal.

And a sealing gas is supplied to a gap between the inner circumferential surface of the non-contact seal and the outer circumferential surface of the rotating shaft to seal the screw rotor type vacuum pump.
The method according to claim 4,

And a sealing gas discharge passage is provided in the motor fixing member so that the sealing gas supplied into the gap between the inner circumferential surface of the non-contact seal and the outer circumferential surface of the rotating shaft is discharged.
The method according to claim 3,

And a sealing ring provided between the inner circumferential surface of the motor fixing member and the outer circumferential surface of the non-contact seal so as to prevent leakage of the sealing gas so that sealing rings are provided above and below the sealing gas supply passage.
The method according to claim 1,

A screw rotor formed on the outer circumferential surface of the pair of screw rotors, wherein the lead angle is continuously changed.
The method according to claim 1,

The screw thread formed on the outer circumferential surface of the pair of screw rotors, the screw rotor type vacuum pump, characterized in that connected continuously along the back lead section (a), the uneven lead section (b), the back lead section (c).
The method according to claim 1,

Screw rotor type vacuum pump, characterized in that the outer diameter of any one of the pair of screw rotor is larger than the outer diameter of the other screw rotor.
The method according to claim 9,

The screw rotor type vacuum pump, characterized in that the motor is installed inside the screw rotor having a large outer diameter.