JPH11166530A - High speed rotary apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce positional dislocation of a rotary body by allowing to abut to sliding members in an operation state anticipated that the rotary body is largely dislocated from a reference rotary position by arranging a sliding member driving mechanism capable of moving the sliding members according to an apparatus operating state and variably setting a tolerance. SOLUTION: A touchdown bearing 8 being plural sliding members is arranged under a disk body 21, and a sliding member driving mechanism 9 is arranged to vertically move this touchdown bearing 8 according to a rotating speed of a rotary shaft 2 being an apparatus operating state. The sliding member driving mechanism 9 has a control means 92 which detects a rotating speed of the rotary shaft 2 by a frequency in a motor driving signal of an inverter 43 and moves the touchdown bearing 8 upward up to an upper preset position A, if the rotating speed is less than a predetermined preset rotating speed based on this detecting signal (a) and if not, moves it downward to a lower preset position B. Thereby, positional dislocation of a rotary body can be reduced without reducing the service life of the sliding members.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed rotating device such as a turbo-type vacuum pump, a turbo blower, a roots blower, etc., which has a rotary blade and performs a gas compression action and a gas circulation action by the rotation of the rotary blade.

[0002]

2. Description of the Related Art In high-speed rotating equipment such as a turbomachine which has a rotating blade and performs a gas compressing action and a gas circulating action by the rotation of the rotating foil, a non-contact type represented by a gas dynamic pressure bearing, a magnetic levitation bearing and the like. In the case of using a type bearing, it is necessary to prevent the rotating body such as the rotor blade and the rotating shaft supporting the rotor from moving from the reference rotation position due to low speed rotation, disturbance, or the like, and to prevent contact with the bearing or the casing. For this reason, a touchdown bearing as a sliding member may be disposed at a fixed position. This touch-down bearing is in non-contact with the rotating body at the reference rotation position where the rotating body is supported by the bearing and is in a stable state, and if the rotating body moves from the reference rotation position beyond the allowable amount for some reason, Then, it is a safety measure component that comes into contact with this and prevents the rotating body from contacting a bearing, a casing, or the like.

[0003]

On the other hand, in a high-speed rotating device having such a non-contact type bearing, an external force is applied to the rotating body depending on the operating state of the device, such as at the time of rotation acceleration / deceleration or low-speed rotation. Therefore, a displacement from the reference rotation position is necessarily caused. For this reason, for example, in the case of a dynamic pressure gas bearing, a sliding displacement always occurs with the rotating body due to a positional shift occurring at low rotation, and the wear due to the sliding has limited the bearing life. Further, in the case of the magnetic levitation bearing, there is a problem that control for returning the rotating body to the reference rotation position after the displacement has occurred becomes extremely difficult. In order to solve such a problem, it is conceivable to dispose the touch-down bearing in close proximity to the rotating body to prevent displacement, but in this case, the rotating body frequently rotates even during stable operation. It is conceivable that the touchdown bearing comes into contact with the touchdown bearing, which may cause a problem that the life of the touchdown bearing itself is shortened, or that the number of revolutions of the rotating body fluctuates with each contact.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems at once, the present invention has a gas outlet, and performs suction and discharge of gas from the gas outlet by rotation of a rotary blade. A non-contact type bearing that rotatably supports a rotating body including the rotating blades, and a sliding member that suppresses deviation from a reference rotation position of the rotating body to an allowable amount or less by contacting the rotating body. In the high-speed rotating device provided, a sliding member driving mechanism capable of variably setting the allowable amount by moving the sliding member according to the operating state of the device is provided.

[0005] In such a case, the operating state of the equipment is monitored, and when the rotating body is in a stable operating state, the sliding member is moved in a direction away from the rotating body to set the allowable amount to a large value, thereby enabling the sliding operation. The contact of the rotating body with the member can be prevented. If the rotating state of the rotating body is expected to greatly deviate from the reference rotation position, the sliding member is brought closer to the rotating body and the allowable amount is reduced, so that the displacement of the rotating body is brought into contact with the sliding member. Can be reduced. In other words, the sliding member has a function of suppressing the displacement of the rotating body only when necessary by actively moving, and the displacement of the rotating body can be reduced without reducing the life of the sliding member. As a result, for example, if the non-contact type bearing is a magnetic levitation bearing, the position control of the rotating body becomes easy,
Further, if the non-contact bearing is a dynamic pressure gas bearing, the bearing and the rotating body can be completely brought into non-contact during operation, so that the bearing life can be extended.

Specific examples of the operating state of the equipment which are parameters for setting the allowable amount include the number of revolutions of the rotating body, the gas pressure at the gas inlet, and the like.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a schematic cross-sectional view schematically showing the internal structure of a turbo vacuum pump 100 which is a high-speed rotating device of the present embodiment. The turbo type vacuum pump 100 according to the present embodiment includes:
As shown in FIG. 1, a cylindrical casing 5, a rotary blade 1 having a plurality of blades 11 provided on the outer periphery, a rotary shaft 2 screwed to the rotary blade 1, and the rotary shaft 2 It comprises dynamic pressure gas bearings 31 and 32 as non-contact type bearings rotatably supported, and an electric motor 4 for rotating the rotating shaft 2, and is used by standing up with the rotating blades 1 upward.

The casing 5 has a rotor holding chamber 51 for holding the rotor 1, and a bearing holding chamber 52 provided continuously below the rotor holding chamber 51 for loosely fitting the rotating shaft 2. Become. In the rotor holding chamber 51, a gas inlet 53 opening above the rotor 1, a gas outlet 54 opening to the side of the rotor 1, and a fixed member alternately arranged with the wing 11. The wing body 55 is provided.

In the bearing holding chamber 52, a motor disposition portion 55 in which an electric motor 4 described later can be disposed near the center thereof, and a thrust bearing disposition portion 56 in which a thrust bearing 32 described later is disposed near a lower end thereof. Are provided. Further, an external connection path 6 extends from the lower end and communicates with an external port 7 opened on the outer surface of the casing 5. The rotating shaft 2 is screwed through the rotating wing 1, and a disk 21 is integrally fixed near the end.

The dynamic pressure gas bearings 31 and 32 include a journal bearing 31 for supporting the rotating shaft 2 against a load acting in the journal direction, and a thrust bearing 32 for supporting the rotating shaft 2 against a load acting in the thrust direction. It is composed of The journal bearings 31 are disposed at two places from above and below the rotating shaft 2. For example, the journal bearings 31 are formed by rolling a rectangular thin plate and have one end thereof in the bearing holding chamber 5.
A journal support plate 33 which is supported on the inner wall surface of the rotary shaft 2 and is disposed around the rotary shaft 2; and a journal support plate 33 is provided around the journal support plate 33 to elastically urge the journal support plate 33 inward to rotate the rotary shaft 2. 2 and a plurality of leaf spring members 34 to be pressed against. The thrust bearing 32 includes, for example, thrust support plates 36 disposed above and below the disk body 21, respectively.
A plate spring member 37 is provided above and below the thrust support plate 36 and elastically urges the thrust support plate 36 to press and contact the disc body 21. When the rotating shaft 2 is stationary or at a certain rotational speed or less, the journal support plate 3
3 and the thrust support plate 36 are brought into close proximity or close contact with the rotary shaft 2 by the elastic biasing force of the leaf spring members 34 and 37, and support the gas. Using the rotation axis 2
A dynamic pressure is generated on the periphery of the disk body 21 and on the upper and lower surfaces of the disk body 21, and the dynamic pressure causes the journal support plate 33 and the thrust support plate 36 to recede to form a gas film, thereby supporting the rotating shaft 2 in a non-contact manner. Have The gas such as nitrogen supplied to the dynamic pressure gas bearings 31 and 32 is supplied from the external port 7 through the external connection path 6. Also,
In this embodiment, a position where the gas film is formed and the rotating shaft 2 stably rotates in a non-contact state is defined as a reference rotation position.

The electric motor 4 is, for example, a DC brushless type in which the rotor 41 is fixed to the rotating shaft 2 and the stator 42 is supported around the rotor 41 by the casing 5. It is provided integrally and drives the rotating shaft 2 directly. In this embodiment, the inverter 43 is used as a drive source of the electric motor 4,
The inverter 43 is a known inverter that can rotate the electric motor 4 at a rotation speed proportional to the frequency of the motor drive signal.

The turbo-type vacuum pump 1 configured as described above
00 rotates the rotary wing 1 by the electric motor 4 so that the gas sucked in from the gas inlet 53 is supplied to the wing body 11.
It blows off by the interaction between the gas turbine and the fixed wing body 55, and performs a pump function of forcibly exhausting gas from the gas outlet 54. In this turbo-type vacuum pump 100, the rotating body corresponds to a rotating blade 1, a rotating shaft 2 and a rotor 4.
Becomes 1.

In this embodiment, the touch-down bearing 8 as a plurality of sliding members is disposed below the disk 21 and the touch-down bearing 8 is adjusted to the number of rotations of the rotating shaft 2 in a device operating state. A sliding member drive mechanism 9 that moves up and down accordingly is provided. Sliding member drive mechanism 9
Detects an electric actuator 91 that moves the touch-down bearing 8 up and down between an upper set position and a lower set position, and detects the number of revolutions of the rotating shaft 2 based on the frequency of the motor drive signal of the inverter 43, and A control means 92 for moving the touch-down bearing 8 up to the upper set position A if the rotational speed is lower than the predetermined set rotational speed, and moving the touch-down bearing 8 down to the lower set position B otherwise. And In addition,
The set number of revolutions is set to a number of revolutions near where a gas film of a sufficient pressure capable of supporting the rotating shaft 2 on the dynamic pressure gas bearings 31 and 32 in a non-contact manner is formed. On the other hand, the upper setting position A is set to be the same as or slightly above the natural position where the rotation shaft 2 does not act on the addition of the thrust support plate 36, that is, the reference rotation position in the thrust direction.
In this way, the allowable amount of deviation at the upper setting position A is set to substantially zero. Further, the lower setting position B is substantially the same as the fixed position of the conventional touchdown bearing, that is, is set in a range where the touchdown bearing 8 can prevent the rotating shaft 2 from contacting the casing 5 and the like.

The operation of the rotating body of this embodiment having the above-described structure is as follows. At the stage when the turbo-type vacuum pump 100 is operated to start rotating the rotating body, that is, while the rotating speed of the rotating body is lower than the set rotating speed, the rotating body is supported by the touch-down bearing 8 in the thrust direction and the reference rotation is performed. Will rotate in position. If the number of rotations exceeds the set number of revolutions, the touch-down bearing 8 moves downward, but at this time, due to the pressure of the gas film,
The rotating body is supported in the non-contact state in the vicinity of the reference rotation position. When the rotation of the rotating body is stopped, the touchdown bearing 8 rises to the upper set position A when the rotation becomes equal to or less than the set rotation, and slidably comes into contact with the rotating body again to support the same. Will be.

Therefore, the rotating body can be positioned in the vicinity of the reference rotating position from start to finish, without being largely displaced downward at the time of low rotation unlike the conventional rotating body. Further, in the related art, the thrust support plate 36 and the disk body 21 that have been completely in sliding contact at the time of low rotation until a gas film capable of supporting the rotating body is formed, the rotating body touches down at low rotation. Since the bearings 8 are supported by the bearings 8, the bearings are brought into a non-contact state, which contributes to reduction of wear, and also increases the life of the dynamic pressure gas bearing 32.

Next, a second embodiment of the present invention will be described with reference to FIGS. The same members as those in the first embodiment are denoted by the same reference numerals. The turbo type vacuum pump 101 of the present embodiment is different from that of the first embodiment only in the sliding member drive mechanism. That is, the turbo vacuum pump 101 has a plurality of touch-down bearings 8 disposed below the disk body 21, and the touch-down bearings 8 are connected to the gas introduction ports 53 in a device operating state.
Are supported by a sliding member drive mechanism 109 that moves up and down according to the gas pressure at This sliding member drive mechanism 109
Are a disk-shaped plate 191 provided at the lower end of the support column 81 supporting the touch-down bearing 8, and a support hole 192 provided at the bottom of the thrust bearing disposition portion 56 and supporting the plate 191 in a vertically movable manner. And a coil spring 193 that elastically urges the plate 191 downward, and a fluid path 194 having one end opened to the bottom surface of the support hole 192 and the other end opened to the gas inlet 53. 3 and 4, a sealing member 195 is provided on the side surface of the plate body 191 so as to support the support hole 1.
The fluid path 194 and the thrust bearing arrangement portion 56 are prevented from communicating with each other by being brought into close contact with the side surface of the thrust bearing 92.

When the turbo-type vacuum pump 101 is operated normally and the pressure of the gas inlet 53 is vacuum or almost vacuum, the gas is introduced into the coil spring 193 and the thrust bearing arrangement portion 56. The touchdown bearing 8 is urged downward by the gas pressure and is held at the lower setting position B shown in FIG. Thus, when the gas pressure of the gas inlet 53 exceeds a predetermined value due to, for example, a break in the vacuum state of the vacuum chamber, an excessively large downward load acts on the rotating body, In such a case, the gas pressure of the gas inlet 53 is also guided to the support hole 192 via the fluid path 194, thereby lifting the plate body 191 upward and moving the touchdown bearing 8 to the upper set position A shown in FIG. To support the rotating body so as not to largely move downward by antagonizing the load. In addition,
The area of the plate 191 is set to a value that can support the rotating body by the gas pressure of the gas inlet 53 acting.

Accordingly, in such a case, the rotating body does not shift significantly downward even when the gas pressure of the gas inlet 53 increases, unlike the conventional rotating body, and remains at the vicinity of the reference rotating position throughout. Can be done. In addition,
The sliding member drive mechanism is not limited to the present embodiment, and the gas inlet 5
3, a pressure detecting means for detecting the pressure, and an electric actuator for driving the touch-down bearing 8 up and down according to the detected pressure may be used.

According to the first and second embodiments, the following basic effects can be obtained. That is, since the touch-down bearing is actively moved and has a function of suppressing the axial movement of the rotating body in the thrust direction only when necessary, the reference of the rotating body can be performed without reducing the life of the touch-down bearing. The displacement from the rotational position can be reduced, which can contribute to the reduction of vibration and the like.

The present invention is not limited to the above. For example, both the rotation speed and the gas inlet pressure may be monitored, and the touchdown bearing may be moved depending on either condition. Of course, the operation state of the device is not limited to the rotation speed and the gas inlet pressure. In addition, a touchdown bearing and a similar sliding member driving mechanism may be added to suppress not only the displacement in the thrust direction but also the displacement of the rotating body in the journal direction. The touch-down bearing may be provided at any position as long as it can support the rotating body. For example, a similar effect can be obtained even at a position where the touch-down bearing is brought into direct contact with the rotor.

Further, the touch-down bearing 8 of the first and second embodiments and the sliding member driving mechanism 9 or 109 for driving the same may be applied to a turbo vacuum pump having a magnetic levitation bearing. According to the above-described configuration, in the case of the magnetic levitation bearing, a force (particularly, a thrust direction) acts on the rotating body due to a change in vibration or pressure ratio at the time of starting or stopping, and a displacement occurs in the rotating body. In such a case, the displacement can be suppressed by the touch-down bearing 8, so that the bearing control becomes easy. In addition, gas inlet 53
Even if the gas pressure becomes large, the rotating body can be positioned in the vicinity of the reference rotating position from beginning to end without being largely displaced downward, so that the bearing control is also facilitated.

When the bearing is a hydrodynamic gas bearing, the following configuration may be adopted. That is, as shown in FIG. 5, the turbo type vacuum pump 102
Journal support plate 33 and leaf spring material 3 in 1 and 32
4. A magnetic material is used for the thrust support plate 36 and the leaf spring member 37, and the dynamic pressure gas bearings 31 and 32 in the casing are used.
An electromagnet 201 is embedded in the outer periphery of the device. In addition,
The touchdown bearing 8 and its driving mechanism 9 employ, for example, the same ones as in the first embodiment. Further, a control device 202 for driving the electromagnet 201 is provided externally.
3. The leaf spring material 34, the thrust support plate 36, and the leaf spring material 37 can be moved in a direction away from the rotating shaft 2. In such a case, in the stop state,
The journal support plate 33 and the thrust support plate 36 are completely pressed and adhered to the rotating shaft 2 by the leaf spring members 34 and 37, so that the supporting state of the rotating body including the rotating shaft 2 can be improved without any play. The effect can be obtained.
Further, during operation, a current is applied to the electromagnet 201 during low rotation to move the journal support plate 33, the leaf spring material 34, the thrust support plate 36, and the leaf spring material 37 in a direction away from the rotary shaft 2. As in the first embodiment, the rotating shaft 2
And the journal support plate 33 or the thrust support plate 36 can be kept in a non-contact state all the time.

Further, as a unique effect, the balance of the rotating body in the manufacturing process of such a turbo type vacuum pump 102 can be made preferable. That is, conventionally, in balancing a rotating body, a balance adjustment is performed by measuring an unbalance amount while rotating the rotating body at a low speed on a balancing machine. For this reason, in a state where the dynamic pressure gas bearing is incorporated, the imbalance due to the contact between the rotating body and the dynamic pressure gas bearing cannot be measured, so that the unbalance amount cannot be accurately measured. Therefore, it is necessary to carry out balancing while the dynamic pressure gas bearing is removed, and then disassemble the rotary blade 1, the rotary shaft 1 and the like once and re-install the dynamic pressure gas bearing for final assembly. The balance as an assembly could not be obtained.

However, in the case of the above, the rotor and the dynamic pressure gas bearings 31 and 32 are driven by the electromagnet 201 in the state of a final assembly incorporating the dynamic pressure gas bearings 31 and 32.
32 can be balanced without contact
The process can be simplified and accurate balance can be obtained. Note that, at the time of balancing, if only a necessary portion Y including the electromagnet 201 is configured to be separable in the casing as shown by a dotted line in the drawing, for example, the weight of the portion to be mounted on the balancing machine can be reduced. An accurate balance can be obtained.

The present invention is not limited to a turbo-type vacuum pump, but is applied to a turbo machine such as a turbo blower or a roots blower having a rotary blade and performing a gas compression action and a gas circulation action by the rotation of the rotary blade. If applicable, it is applicable. In addition, the configuration is not limited to the illustrated example, and a cam follower is used in the embodiment as a touch-down bearing, for example, without departing from the spirit of the present invention. However, various modifications such as selection of an angular ball bearing are possible.

[0026]

According to the present invention as described above,
The sliding member drive mechanism moves the sliding member in accordance with the operation state of the device so that the allowable amount can be variably set, so that the sliding member is actively moved to suppress displacement of the rotating body only when necessary. The displacement of the rotating body can be reduced without reducing the life of the sliding member. As a result, for example, when the non-contact type bearing is a magnetic levitation bearing, the position control of the rotating body becomes easy, and when the non-contact type bearing is a hydrodynamic gas bearing, the bearing and the rotating body are operated. In some cases, it is possible to bring the bearing completely out of contact, thereby achieving effects such as an increase in bearing life.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a turbo vacuum pump showing a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of a turbo type vacuum pump showing a second embodiment of the present invention.

FIG. 3 is a schematic enlarged view showing a state where the touch-down bearing of the embodiment is at an upper set position.

FIG. 4 is a schematic enlarged view showing a state where the touchdown bearing of the embodiment is at a lower set position.

FIG. 5 is a schematic sectional view of a turbo vacuum pump showing a modification of the present invention.

[Explanation of symbols]

100, 101, 102: high-speed rotating equipment (turbo-type vacuum pump) 1: rotating blades 1, 2, 41: rotating body 31, 32: non-contact type bearing (dynamic pressure gas bearing) 53 ... gas inlet 54 ... gas outlet 8 ... sliding member (touch-down bearing) 9, 109 ... sliding member drive mechanism

Claims (3)

[Claims] A non-contact type bearing having a gas outlet, performing suction and discharge operations of gas from the gas outlet by rotation of the rotor, and rotatably supporting a rotor including the rotor. In a high-speed rotating device having a sliding member that suppresses the deviation of the rotating body from the reference rotation position to an allowable amount or less by abutting the rotating body, the sliding member is moved according to the operating state of the device. A high-speed rotating device provided with a sliding member drive mechanism capable of variably setting an allowable amount. 2. The high-speed rotating device according to claim 1, wherein the sliding member drive mechanism is configured to set the allowable amount according to the number of rotations of the rotating body. 3. The high-speed rotating apparatus according to claim 1, wherein the sliding member driving mechanism is configured to set the allowable amount according to a gas inlet port pressure.