JP2020143582A - Rotary machine - Google Patents

Abstract

To provide a rotary machine that expands an operation area capable of securing stability in an axial line direction of a turbo pump more than before.SOLUTION: A rotary machine includes: a rotation shaft 2; an impeller 3 fitted to the rotation shaft; and a casing 1 storing the impeller therein and supporting the rotation shaft so as to be rotatable. The casing has a wall surface facing a back face 3a of the impeller and the wall surface is provided with a variable volume mechanism 4 capable of varying a volume of a space held between the back face and the wall surface.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rotating machine.

The following Patent Document 1 discloses a pump provided with an axial equilibrium device. The pump comprises a rotor with a stator and impeller and an axial equilibrium device provided on the impeller, which has a rear equilibrium chamber and passage provided between the impeller and the stator. The passages allow the fluid to drain from the fluid duct into the rear equilibrium chamber, and the fluid pressure in the equilibrium chamber compensates for the pressure exerted by the fluid on the rest of the rotor to equilibrate the rotor in the axial direction. is there. The passage comprises an upstream nozzle, a downstream nozzle and an intermediate annular chamber provided between the wall of the impeller and the wall of the stator.

Special Table 2012-514713

By the way, in such a pump (rotary machine), the stator shape (case shape) on the back surface of the impeller affects the stability of the axial equilibrium device in principle of equilibrating the rotor in the axial direction. Since this case shape cannot be changed after the rotating machine is assembled, in the actual operation of the rotating machine, the case must be operated only in the rotation range (operating range) where the above stability can be ensured.

The present invention has been made in view of the above circumstances, and an object of the present invention is to expand the operating range in which stability can be ensured.

In order to achieve the above object, in the present invention, as a first solution relating to a rotating machine, a rotating shaft, an impeller mounted on the rotating shaft, and the impeller are accommodated and the rotating shaft is rotated. A means is adopted in which a casing that freely supports the casing is provided, and a volume variable mechanism that changes the volume of the space sandwiched between the casing and the impeller is provided on the wall surface facing the back surface of the impeller. To do.

In the present invention, as a second solution for a rotating machine, in the first solution, the volume variable mechanism includes a ring member provided on the wall surface so as to be concentric with the rotation shaft, and the ring member. A means is adopted that includes a drive mechanism for moving the ring member forward and backward with respect to the back surface, and an airtight member that is deformable and maintains airtightness between the ring member and the wall surface.

In the present invention, as a third solution relating to a rotary machine, in the second solution, the drive mechanism is a ball screw mechanism screwed between the wall surface and the ring member. adopt.

In the present invention, as a fourth solution for a rotating machine, in the third solution, the airtight member is a diaphragm interposed between the wall surface and the ring member.

In the present invention, as a fifth solution relating to a rotating machine, in the second solution, the airtight member is a bellows interposed between the ring member and the wall surface, and the drive mechanism is the drive mechanism. A means of supplying and exhausting the driving fluid from the wall surface side into the bellows is adopted.

In the present invention, as the sixth solution for the rotating machine, the means of being a turbo pump is adopted in any of the first to fifth solutions.

According to the present invention, it is possible to change the volume of the space sandwiched between the wall surface of the casing and the back surface of the impeller, and thus it is possible to expand the operating area in which stability can be ensured as compared with the conventional case.

It is sectional drawing (a) which shows the structure of the turbo pump which concerns on 1st Embodiment of this invention, and the front view (b) of the volume variable mechanism. It is sectional drawing which shows the structure of the turbo pump which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the first embodiment of the present invention will be described. As shown in FIG. 1, the turbo pump according to the first embodiment includes a casing 1, a rotating shaft 2, an impeller 3, a volume variable mechanism 4, and the like.

The casing 1 is the housing of the turbo pump P, and is formed with a flow path for accommodating the rotary shaft 2 and the impeller 3 and the like and for flowing the fluid. The casing 1 includes a wall surface 1a facing the back surface 3a of the impeller 3. As shown in the figure, the wall surface 1a is an orthogonal surface that is substantially orthogonal to the axial direction (extending direction) of the rotating shaft 2.

As shown in the drawing, a ring-shaped recessed portion 1b is formed in the casing 1, and through holes 1c located on a plurality of sides are discretely formed in the recessed portion 1b. The recessed portion 1b is a portion that accommodates the ring member 4a described later. Further, the through hole 1c has a thread (female screw) formed on the inner peripheral surface thereof, and is screwed with a screw rod 4f described later.

The rotating shaft 2 is a columnar (round bar) member made of metal, and the impeller 3 is concentrically mounted at the tip, and the portion near the rear end is supported by the casing 1 via a bearing (not shown). ing. That is, the casing 1 described above is also a support member that rotatably supports the rotating shaft 2 via bearings.

The impeller 3 is fixed to the rotating shaft 2 so that the central axis is coaxial with the axis (center of rotation) of the rotating shaft 2, and a plurality of blades (wings) extending radially from the central axis are formed on the surface of the impeller 3. Be prepared. The impeller 3 is a centrifugal blade that sucks liquid oxygen R from the axial direction (inflow port m1) and sends it out in the circumferential direction by rotating.

Further, the impeller 3 includes a back surface 3a facing the wall surface 1a of the casing 1 as described above. The back surface 3a is a surface substantially orthogonal to the axial direction (extending direction) of the rotating shaft 2, and is substantially parallel to the wall surface 1a of the casing 1. As shown by the arrows in FIG. 1A, such an impeller 3 faces the casing 1 in close proximity to the casing 1 at an end portion in a direction perpendicular to the center of rotation of the impeller 3.

The volume variable mechanism 4 is provided on the wall surface 1a of the casing 1 described above, and changes the volume of the space sandwiched between the wall surface 1a and the back surface 3a of the impeller 3. The volume variable mechanism 4 includes a ring member 4a, a drive mechanism 4b, and a diaphragm 4c.

As shown in FIG. 1A, the ring member 4a is provided on the wall surface 1a so as to be concentric with the rotating shaft 2, and is housed in the recessed portion 1b of the casing 1. Further, as shown in FIG. 1B, the ring member 4a has a plurality of straight grooves 4e formed radially on the surface 4d facing the back surface 3a of the impeller 3.

The drive mechanism 4b is a mechanism for moving the ring member 4a forward and backward with respect to the back surface 3a, and is, for example, a ball screw mechanism that engages between the wall surface 1a and the ring member 4a. That is, in this drive mechanism 4b, a screw thread (male screw) is formed on the peripheral surface, the tip portion is connected to the back surface side of the ring member 4a, and the screw rod 4f is screwed into the through hole 1c of the casing 1. It is provided with a drive source 4g for rotationally driving the screw rod 4f.

The diaphragm 4c is a flexible metal ring plate, and is an airtight member that maintains airtightness between the ring member 4a and the wall surface 1a (recessed portion 1b). That is, the diaphragm 4c is interposed between the wall surface 1a and the ring member 4a and is deformable, the inner peripheral end is airtightly connected to the back surface side of the ring member 4a, and the outer peripheral end is the recessed portion 1b of the casing 1. Is airtightly connected to.

Such a diaphragm 4c is a kind of sealing member. That is, the diaphragm 4c prevents the fluid from leaking to the outside from the meshing portion between the thread (female screw) of the through hole 1c and the thread (male screw) of the screw rod 4f screwed into the thread (female screw). To prevent.

As the impeller 3 rotates, such a turbo pump P sucks fluid into the flow path from the front side of the impeller 3 and sends it out in the circumferential direction of the impeller 3. As shown by the broken line arrow, a part of the fluid sent out in the circumferential direction passes through a minute gap, wraps around the back surface 3a of the impeller 3, passes through the peripheral surface of the rotating shaft 2 as a leaking fluid, and goes to the outside. Flow out. The flow rate of the leaked fluid varies depending on the operating region of the turbo pump P, that is, the rotating region of the rotating shaft 2.

The volume variable mechanism 4 of the first embodiment stabilizes the position of the rotating shaft 2 in the axial direction by variably adjusting the flow rate of the leaking fluid. That is, the volume variable mechanism 4 desires the position of the rotating shaft 2 in the axial direction based on the flow rate difference between the fluid (main fluid) flowing on the front surface side of the impeller 3 and the leaking fluid flowing on the back surface 3a side of the impeller 3. Set the position stably.

Here, the volume variable mechanism 4 can move the ring member 4a forward / backward with respect to the back surface 3a of the impeller 3 by operating the drive source 4g, that is, the ring member 4a and the back surface 3a of the impeller 3 It has a function to change the volume of the space sandwiched between the two.

That is, the volume variable mechanism 4 in the present embodiment adjusts the distance between the ring member 4a and the back surface 3a of the impeller 3 according to the operating region of the turbopump P, that is, the rotating region of the rotating shaft 2, so that the rotating shaft 2 The volume of the space is set so that the position in the axial direction of the above space is stable at a desired position.

According to the present embodiment as described above, the volume of the space can be optimally set so that the desired position of the rotating shaft 2 in the axial direction is stabilized according to the operating region of the turbopump P. It is possible to expand the operating range of the turbopump P, which can secure stability as compared with the conventional case in which the volume of the space is constant.

Next, the second embodiment of the present invention will be described. In the turbo pump according to the second embodiment, as shown in FIG. 2, a second recessed portion 1d is formed on the wall surface 1a of the casing 1 in addition to the recessed portion 1b described above. Further, a second volume variable mechanism 4A is provided in place of the volume variable mechanism 4 described above.

The second recessed portion 1d is provided on the back side of the recessed portion 1b, that is, on the side away from the back surface 3a of the impeller 3 than the recessed portion 1b, and is for accommodating the bellows 4j (bellows) described later. is there.

The second volume variable mechanism 4A includes a second ring member 4h, a bellows 4i, and a gas supply device 4j. The second ring member 4h is a ring-shaped flat plate having substantially the same shape as the ring member 4a of the first embodiment, and a plurality of straight grooves 4e are formed on the surface 4d, but the back surface shape is slightly different from that of the ring member 4a. It's different. That is, one end of the bellows 4i is coaxially connected to the back surface of the second ring member 4h, and thus a convex portion 4k having a size corresponding to the diameter of the bellows 4i is formed on the back surface.

The bellows 4i is a metal component that is substantially cylindrical and can be expanded and contracted in the axial direction. The bellows 4i can be expanded and contracted in a direction orthogonal to the surface of the second ring member 4h, that is, in the left-right direction of FIG. 2, one end (left end) is airtightly connected to the convex portion 4k of the second ring member 4h, and the other. The end (right end) is airtightly connected to the second recess 1d. Such a bellows 4i freely supports the second ring member 4h with respect to the back surface 3a of the impeller 3.

The gas supply device 4j is connected to the other end (right end) of the bellows 4i via a manifold formed in the casing 1, and a driving fluid is introduced into the bellows 4i from the other end (right end) side, that is, the wall surface 1a side. It is a fluid supply means for supplying and exhausting air. That is, the gas supply device 4j adjusts the degree of expansion and contraction of the bellows 4i, that is, the distance of the second ring member 4h to the back surface 3a of the impeller 3 by controlling the supply amount of the driving fluid to the bellows 4i. The driving fluid is, for example, a liquid such as oil.

Similar to the volume variable mechanism 4 of the first embodiment, the second volume variable mechanism 4A in the second embodiment changes the flow rate of the leaking fluid that passes through the minute gap and wraps around the back surface 3a of the impeller 3. By adjusting, the position of the rotating shaft 2 in the axial direction is stabilized. That is, the second volume variable mechanism 4A moves the second ring member 4h forward / backward with respect to the back surface 3a of the impeller 3 by operating the gas supply device 4j, thereby causing the second ring member 4h and the impeller 3 to move forward / backward. The volume of the space sandwiched between the back surface 3a and the back surface 3a is variable.

As a result, the flow rate difference between the fluid (main fluid) flowing on the front surface side of the impeller 3 and the leaking fluid flowing on the back surface 3a side of the impeller 3 changes, so that the position of the rotating shaft 2 in the axial direction is stabilized at a desired position. To become. That is, the second volume variable mechanism 4A adjusts the distance between the second ring member 4h and the back surface 3a of the impeller 3 according to the operating region of the turbopump P, that is, the rotating region of the rotating shaft 2, thereby adjusting the rotating shaft. The volume of the space is set so that the position of 2 in the axial direction is stable at a desired position.

According to such a second embodiment, the volume of the space can be optimally set so that the desired position of the rotating shaft 2 in the axial direction is stabilized according to the operating region of the turbopump P. Therefore, it is possible to expand the operating range of the turbopump P, which can secure stability as compared with the conventional case in which the volume of the space is constant.

The present invention is not limited to the above embodiment, and for example, the following modifications can be considered.
(1) In the above embodiment, the present invention is applied to stabilize the position of the rotating shaft 2 in the axial direction in the turbo pump P, but the present invention is not limited thereto. That is, the present invention can be applied to the stabilization of the rotating shaft of various rotating machines other than the turbo pump P.

(2) In each of the above embodiments, the volume variable mechanism 4 and the second volume variable mechanism 4A have been described, but the present invention is not limited thereto. That is, the configuration of the volume variable mechanism in the present invention is not limited to the volume variable mechanism 4 and the second volume variable mechanism 4A.

(3) In the above embodiment, a plurality of straight grooves 4e are provided on the surface 4d of the ring member 4a and the second ring member 4h, but the present invention is not limited thereto. The plurality of straight grooves 4e have a function of stabilizing the flow of the leaking fluid on the back surface 3a of the impeller 3, but may be omitted if necessary.

1 Casing 1a Wall surface 1b Recessed part 1c Through hole 1d Second recessed part 2 Rotating shaft 3 Impeller 3a Back surface 4 Volume variable mechanism 4A Second volume variable mechanism 4a Ring member 4b Drive mechanism 4c Diaphragm 4d Surface 4e Straight groove 4f Rod 4g Drive source 4h 2nd ring member 4i Bellows 4j Gas supply device 4k Convex part

Claims (6)

The axis of rotation and
The impeller mounted on the rotating shaft and
It is provided with a casing that accommodates the impeller and rotatably supports the rotating shaft.
A rotating machine characterized in that a wall surface of the casing facing the back surface of the impeller is provided with a volume variable mechanism that changes the volume of the space sandwiched between the casing and the back surface. The volume variable mechanism is
A ring member provided on the wall surface so as to be concentric with the rotating shaft,
A drive mechanism that moves the ring member forward and backward with respect to the back surface,
The rotary machine according to claim 1, further comprising an airtight member that is deformable and maintains airtightness between the ring member and the wall surface. The rotary machine according to claim 2, wherein the drive mechanism is a ball screw mechanism screwed between the wall surface and the ring member. The rotary machine according to claim 3, wherein the airtight member is a diaphragm interposed between the wall surface and the ring member. The airtight member is a bellows interposed between the ring member and the wall surface.
The rotary machine according to claim 2, wherein the drive mechanism is a fluid supply means for supplying and exhausting a drive fluid into the bellows from the wall surface side. The rotary machine according to any one of claims 1 to 5, wherein the rotary machine is a turbo pump.

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