JP2020066090A - Method for manufacturing non-contact seal structure, and rotary machine - Google Patents

Abstract

To provide a method for manufacturing a non-contact seal structure in which a manufacturing time is shortened and a manufacturing cost can be suppressed as compared to before, and provide a rotary machine.SOLUTION: According to the present invention, a method for manufacturing a non-contact seal structure includes a workpiece fixation step, a rotational step, and a cutting step. The manufacturing method is provided as follows: a workpiece is fixed rotatably around a first rotating shaft being a predetermined rotating shaft in the workpiece fixation step; the workpiece is rotated around the first rotating shaft in the rotational step, and a tool having a cutting edge is rotated around the second rotating shaft different from the first rotating shaft; at least one position of the workpiece and the tool is displaced in the cutting step; the workpiece is brought into contact with the tool and an outer circumferential side or the side face of the workpiece is subjected to the cutting, and thereby the non-contact seal structure having a helical structure is formed; the spiral structure has a helical protrusion and a helical recess; and the rotational step is continuously performed in the cutting step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a non-contact seal structure and a rotating machine.

  There is a rotary machine that includes at least a rotating body that rotates about a rotating shaft and a housing configured to cover the rotating body. Examples of rotary machines include NC rotary table devices, centrifugal fluid machines, pumps, and the like. In such a rotary machine, a gap is formed between the rotating body and the housing in order to rotate the rotating body. In order to prevent foreign matter from entering the inside of the housing from the outside through such a gap or to prevent the fluid (such as lubricating oil) inside the housing from leaking to the outside, there is no contact with the rotating body. A seal structure may be provided (see Patent Document 1, for example). In this specification, such a rotating body is referred to as a non-contact seal structure.

Re-table 2015-115300

  However, in order to manufacture the non-contact seal structure described in Patent Document 1 or the like, it is necessary to form a spiral thread groove (unevenness) on the outer periphery thereof. If it is attempted to form such unevenness by conventional lathe processing, there is a problem that the working time is long and the manufacturing cost is high.

  The present invention has been made in view of the above circumstances, and provides a method for manufacturing a non-contact seal structure and a rotating machine, which can shorten the manufacturing time and can suppress the manufacturing cost as compared with the related art. The purpose is to

  According to the present invention, there is provided a method for manufacturing a non-contact seal structure, which includes a work fixing step, a rotating step, and a cutting step, and in the work fixing step, around a first rotation axis that is a predetermined rotation axis. A workpiece is rotatably fixed to the workpiece, and in the rotating step, the workpiece is rotated about the first rotation axis, and a tool having a cutting edge is rotated about a second rotation axis different from the first rotation axis. In the cutting step, at least one of the work and the tool is displaced, and the work and the tool are brought into contact with each other to cut an outer peripheral side surface or an end surface of the work to have a spiral structure. A manufacturing method is provided, wherein a contact seal structure is formed, the spiral structure has a spiral convex portion and a spiral concave portion, and the rotating step is continuously performed during the cutting step. .

  In the manufacturing method according to the present invention, the work and the tool are rotated in mutually different rotation axis directions, one of the work and the tool is displaced while maintaining the rotation, and the outer peripheral side surface or the end surface of the work is cut by bringing them into contact with each other. As a result, a spiral structure can be formed and a non-contact seal structure can be manufactured. As a result, the time required for manufacturing can be shortened, and the manufacturing cost can be suppressed.

Preferably, in the manufacturing method, when the angle formed by the spiral convex portion and the first rotation axis in the side view of the non-contact seal structure is defined as θ, 10 ° ≦ θ ≦ 80 ° is satisfied. A manufacturing method is provided which is carried out.
Preferably, in the manufacturing method, there is provided the manufacturing method, wherein the spiral recesses have height differences that are periodically formed in the extending direction thereof.
Preferably, in the manufacturing method, the number of revolutions of the work per unit time is defined as n_1, the number of revolutions of the tool per unit time is defined as n_2, and the decimal part of the value of n_2 / n_1 is defined as α. A manufacturing method is provided that is implemented to satisfy α ≠ 0 and α ≠ 0.5.
Preferably, there is provided a manufacturing method, which is carried out so as to satisfy 0.03 ≦ α ≦ 0.47 or 0.53 ≦ α ≦ 0.97.
Preferably, in the manufacturing method, the first rotation axis or the predetermined straight line is implemented so as to be orthogonal to the second rotation axis, and the predetermined straight line is parallel to the first rotation axis and the first straight line. A manufacturing method is provided that is a straight line that intersects two axes of rotation.

  Further, according to the present invention, the rotary machine is provided with a housing and a non-contact seal structure, and the housing covers the non-contact seal structure while leaving a gap with the non-contact seal structure. The non-contact seal structure is configured to be rotatable about a predetermined rotation axis, and has a spiral structure on its outer peripheral side surface, and the spiral structure has a spiral convex portion and a spiral shape. A concave portion, the spiral concave portion having a height difference periodically formed in the extending direction thereof, and during the rotation of the non-contact seal structure, from the inside of the gap toward the outside or the There is provided a rotating machine configured to generate an air flow from the outside toward the inside.

The whole block diagram of the rotary machine provided with the non-contact seal structure concerning a 1st embodiment. The figure which shows the air flow produced by rotation of a non-contact seal structure (partial enlarged view of FIG. 1). FIG. 6 is a schematic view showing an aspect of a spiral structure formed on the outer peripheral side surface of the non-contact seal structure. The flowchart which shows the manufacturing method of a non-contact sealing structure. The figure which shows the aspect of a workpiece | work and a tool in a cutting process. [FIG. 6A] A diagram showing a form of a work and a tool at the start of a cutting process, and [FIG. 6B] A diagram showing a form of a work and a tool during a cutting process. The whole block diagram of the rotary machine which concerns on 2nd Embodiment. The whole block diagram of the rotary machine which concerns on 3rd Embodiment. The whole block diagram of the rotary machine which concerns on 4th Embodiment. The figure which shows the helical structure in the non-contact seal structure of the rotary machine which concerns on 5th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. The various features shown in the embodiments described below can be combined with each other.

1. Overall Configuration FIG. 1 is an overall configuration diagram of a rotary machine 1 including a non-contact seal structure 2 according to the first embodiment. As shown in FIG. 1, the non-contact seal structure 2 according to the first embodiment is included in a rotary machine 1 and implemented. The rotary machine 1 is, for example, a pump that transfers an incompressible fluid (water, oil, or the like) or an NC rotary table device installed and used in an NC machine tool, but is not particularly limited.

  The rotary machine 1 includes a non-contact seal structure 2, a housing 3, and a body 4. The non-contact seal structure 2 has a substantially right columnar shape and is configured to be rotatable (spin) about a rotation axis X (an example of a “predetermined rotation axis” in the claims). The non-contact seal structure 2 will be described in more detail in Section 2. The housing 3 is configured to cover the non-contact seal structure 2 while having a gap S with the non-contact seal structure 2. The main body 4 accommodates various structural systems and electric drive systems of the rotary machine 1. In particular, a bearing 41 is interposed in the main body 4 to rotatably support the non-contact seal structure 2. Further, although other components of the main body 4 are not shown, the configuration may be appropriately changed depending on the use of the rotary machine 1.

  As an example, when the rotary machine 1 is an NC rotary table device attached to an NC machine tool, the main body 4 includes, for example, a direct drive motor (hereinafter referred to as DD motor) (not shown) and a spindle, and the non-contact seal structure 2 is provided. A rotary table is implemented as. The DD motor comprises a stator and a rotor, and the stator is fixed to the main body 4, while the rotor is fixed to the spindle. When the rotor is rotationally driven by the DD motor inside the main body 4, the spindle rotates in association with the rotation of the rotor. Then, the rotary table concentrically fixed to the front surface of the spindle rotates. With such a configuration, by using the NC rotary table device, it is possible to rotate the work (working target) attached to the rotary table so as to have a desired posture and perform the working with the tool.

2. Non-contact seal structure 2
In Section 2, the non-contact seal structure 2 will be described in detail. FIG. 2 shows the airflow AF generated by the rotation of the non-contact seal structure 2. When the non-contact seal structure 2 rotates about the rotation axis X counterclockwise when viewed from the left in FIG. 2, the spiral structure 21 having a left-handed twist rotates when viewed from the left in FIG. Thereby, in the gap S between the non-contact seal structure 2 and the housing 3, air flows from right to left in FIG. Then, the pressure on the right side of the clearance S decreases, so that air is sucked from the breathing hole 31 (communication to the clearance S) in the housing 3 and the airflow AF shown in FIG. 2 is formed. Such an air flow AF can prevent foreign matter such as chips from entering the rotating machine 1 from the outside.

  The position of the breathing hole 31 is shown on the upper side in FIG. 2 for the sake of convenience, but it is desirable that the breathing hole 31 is provided at a position (generally on the lower side) where foreign matter is difficult to enter because clean air is preferable. Further, when the non-contact seal structure 2 rotates clockwise around the rotation axis X when viewed from the left in FIG. 2, by implementing the spiral structure 21 with a right twist when viewed from the left in FIG. The same effect can be obtained.

  On the other hand, the non-contact seal structure 2 rotates counterclockwise around the rotation axis X as viewed from the left in FIG. 2 and implements the spiral structure 21 with right-hand twist, or the non-contact seal structure 2 rotates. Rotating clockwise about the axis X as seen from the left in FIG. 2 and implementing a helical structure 21 with a left-handed twist makes it possible to reverse the direction of the airflow AF. With such a configuration, it is possible to prevent the fluid (such as lubricating oil) flowing inside the rotary machine 1 from leaking to the outside. That is, the direction of the airflow AF may be appropriately used depending on the application of the rotary machine 1. In other words, it can be said that the airflow AF is generated from the inside to the outside or from the outside to the inside of the gap S during the rotation of the non-contact seal structure 2. In order for the non-contact seal structure 2 to exhibit the above-mentioned effects, it is preferable that the non-contact seal structure 2 rotates at a high speed of 10 m / s or more in peripheral speed.

  FIG. 3 shows a mode of the spiral structure 21 formed on the outer peripheral side surface 20 of the non-contact seal structure 2. Here, the extending direction of the spiral structure 21 is defined as the P direction, and the periodic direction of the spiral structure 21 is defined as the Q direction. The spiral structure 21 is composed of a spiral recess 22 that is periodically formed and a spiral projection 23 that serves as a boundary between two adjacent spiral recesses 22.

  The spiral concave portion 22 is formed in a scale shape in the P direction (for example, as an aggregate of substantially congruent scales 220 such as a rectangle, a rhombus, and an ellipse). Here, the recessed portion at the substantially center of the scale 220 is referred to as a belly 221, and both end lines of the scale 220 facing in the P direction are referred to as nodes 222. Further, as shown in FIG. 3, the nodes 222 of the two scales 220 adjacent to each other in the P direction are not configured to be completely shared with each other, but are configured to have a shift 222a in the Q direction. However, this is merely an example, and may be implemented in different modes such as preventing the shift 222a from occurring. Further, the length between the bellies 221 of the two scales 220 adjacent to each other in the Q direction is defined as the length fc. Since the spiral concave portion 22 is formed in a scale shape in the P direction, a height difference a occurs between the recessed portion (low portion 222b) at the substantially center of the node 222 and the belly 221. In addition, the spiral convex portion 23 that is a boundary between the two spiral concave portions 22 adjacent to each other in the Q direction also has a height difference formed periodically in the P direction. In FIG. 3, the lower portion 231 and the higher portion 232 of the spiral convex portion 23 are shown. Further, referring again to FIG. 2, the pitch width of the scale 220 in the direction parallel to the rotation axis X is defined as a length ft, and the height difference between the belly 221 and the spiral convex portion 23 is defined as a height h. Each parameter relating to these helical structures 21 is described in more detail in Section 3.3.

  As described above, since the spiral recess 22 is formed in the scale shape, a pressure difference is generated between the antinode 221 and the node 222 in the spiral recess 22 during the rotation of the non-contact seal structure 2. Then, by utilizing the dynamic pressure effect due to the pressure difference, the sealing performance of the non-contact sealing structure 2 is improved as compared with the sealing performance of the conventional non-contact sealing structure (not shown) having a spiral structure. There is an advantageous effect that it is possible.

3. Method of Manufacturing Non-Contact Seal Structure 2 Section 3 describes a method of manufacturing the non-contact seal structure 2 described above. FIG. 4 is a flowchart showing a method for manufacturing the non-contact seal structure 2. FIG. 5 shows an aspect of the work W and the tool 5 during the cutting process. FIG. 6A shows a mode of the work W and the tool 5 at the start of the cutting process, and FIG. 6B shows a mode of the work W and the tool 5 during the cutting process.

3.1 Each Step Hereinafter, each step of the method for manufacturing the non-contact seal structure 2 will be described along each step S1 to S5 of FIG.

[start]
(Step S1)
A work W having a substantially right columnar shape which is a source of the non-contact seal structure 2 is fixed to an NC circular table device (not shown). The workpiece W is configured to be rotatable about a predetermined rotation axis X (an example of the “first rotation axis” in the claims) by the NC circular table device. The step S1 corresponds to the "workpiece fixing step" in the claims. Further, a tool 5 is attached to a spindle of a machining center (not shown) which is close to the work W, and rotates around a predetermined rotation axis Z (an example of "second rotation axis" in claims). Configured to be possible. Further, as shown in FIG. 6A and the like, the tool 5 is provided with cutting edges 51, 51, 51, 51. The number of cutting edges 51 is not particularly limited.

(Step S2)
Subsequently, the workpiece W fixed in step S1 is rotated clockwise about the rotation axis X in the + X direction (left direction in FIGS. 6A and 6B), and the tool 5 attached to the spindle of the machining center is rotated around the rotation axis Z. Then, rotate counterclockwise in the + Z direction (direction from the back to the front of the paper). A straight line that is parallel to the rotation axis X and intersects the rotation axis Z is implemented so as to be orthogonal to the rotation axis Z. However, this is merely an example, and the crossing may be performed at an angle different from a right angle. Alternatively, the rotation axis X and the rotation axis Z may be intersected at a right angle or at an angle other than the right angle. Note that step S2 corresponds to the "rotating step" in the claims.

(Step S3)
Subsequently, while maintaining the rotation of the work W and the tool 5 in step S2, at least one of the positions of the work W and the tool 5 is displaced to bring the work W into contact with the tool 5. Here, as shown in FIGS. 6A and 6B, only the tool 5 is displaced in the −X direction (right direction in FIGS. 6A and 6B), but this is merely an example and the present invention is not limited to this.

(Step S4)
Even after the contact in step S3, the tool 5 is continuously displaced in the −X direction, whereby the workpiece W is cut by the tool 5 for a predetermined time. That is, as shown in FIG. 6B, the spiral structure 21 is formed on the outer peripheral side surface W0 of the work W having a substantially right columnar shape, and when the contact time is completed, the non-contact seal structure 2 is manufactured from the work W. Becomes However, with respect to the location where the spiral structure 21 is formed, the outer peripheral side surface W0 is merely an example, and may be formed on the end surface. Note that steps S3 and S4 correspond to the "cutting step" in the claims.

(Step S5)
Finally, the completed non-contact seal structure 2 is removed from the NC rotary table device, thereby completing a series of manufacturing steps.
[End]

3.2 Number of revolutions per unit time In step S2 described in Section 3.1, the number of revolutions of the work W per unit time is defined as n_1, the number of revolutions of the tool 5 per unit time is defined as n_2, and n_2 It should be noted that defining the fractional part of the value of / n_1 as α implements such that α ≠ 0 and α ≠ 0.5. By satisfying such a value, the angle formed by the spiral structure 21 (specifically, the spiral convex portion 23) and the rotation axis X in the side view of the manufactured non-contact seal structure 2 is θ (Fig. 6B), it can be implemented so as to satisfy 10 degrees ≦ θ ≦ 80 degrees.

  Regarding α, 0.03 ≦ α ≦ 0.47 or 0.53 ≦ α ≦ 0.97 is preferable. Specifically, for example, α = 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0. 13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0. 38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47 or 0.53, 0.54, 0.55 , 0.56, 0.57, 0.58, 0.59, 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0 .68, 0.69, 0.7, 0.71, 0.72, 0 73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, It may be within a range between any two of the numerical values exemplified here.

  Regarding the resulting θ, specifically, for example, θ = 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 degrees, and may be within a range between any two of the numerical values exemplified here.

3.3 Parameters Related to Helical Structure 21 The height h shown in FIG. 3 is the cusp height, and the length fc is the feed amount per cutting edge 51 of the tool 5 shown in FIG. 6A and the like. is there. Here, assuming that the cutting edge radius R of the tool 5 is, the height h and the length fc have the relationship shown in the following [Equation 1].

[Equation 1] h = fc ^ 2 / 8R

That is, the height h can be increased by increasing the length fc and decreasing the cutting edge radius R. In other words, the spiral convex portion 23 can be formed large.

  The length ft shown in FIG. 3 is the feed amount of the tool 5 in the rotation axis X direction per one rotation of the work W shown in FIG. 6A and the like. When the length ft is large, the height a is high. When the height a is high, the airflow AF (see FIG. 2) due to the spiral structure 21 is less likely to occur when the non-contact seal structure 2 rotates. That is, by reducing the length ft, the non-contact seal structure 2 having high sealing performance can be manufactured. However, it should also be noted that if the length ft is made small, the time required for cutting the work W becomes long, and therefore it must be set appropriately.

4. Other Embodiments The rotary machine 1 according to the first embodiment may be further creatively devised by the following aspects.

4.1 Second Embodiment FIG. 7 shows an overall configuration diagram of a rotary machine 1 according to a second embodiment. In the present embodiment, the rotary machine 1 has a radial labyrinth seal 61, which is a non-contact seal, in addition to the spiral structure 21 included in the non-contact seal structure 2. Even with such a configuration, foreign matter such as chips in the rotary machine 1 is prevented from entering from the outside, or fluid (lubricating oil or the like) flowing in the inside is prevented from leaking to the outside as in the first embodiment or more. be able to.

4.2 Third Embodiment FIG. 8 shows an overall configuration diagram of a rotary machine 1 according to a third embodiment. In the present embodiment, the rotary machine 1 has an axial labyrinth seal 62, which is a non-contact seal, in addition to the spiral structure 21 included in the non-contact seal structure 2. With such a configuration, foreign matter such as chips in the rotary machine 1 can be prevented from invading from the outside or the fluid (lubricating oil or the like) flowing inside can be prevented from leaking to the outside as in the first embodiment or more. be able to.

4.3 Fourth Embodiment FIG. 9 shows an overall configuration diagram of a rotary machine 1 according to a fourth embodiment. In the present embodiment, the rotary machine 1 has an oil seal 63 that is a contact seal, in addition to the spiral structure 21 included in the non-contact seal structure 2. Even with such a configuration, foreign matter such as chips in the rotary machine 1 is prevented from entering from the outside, or fluid (lubricating oil or the like) flowing in the inside is prevented from leaking to the outside as in the first embodiment or more. be able to.

4.4 Fifth Embodiment FIG. 10 shows a spiral structure 21 included in the non-contact seal structure 2 of the rotary machine 1 according to the fifth embodiment. In the present embodiment, the spiral convex portion 23 is configured to be substantially flat as shown in FIG. 10 by polishing the low portion 231 and the high portion 232 shown in FIG. Even with such a configuration, foreign matter such as chips in the rotary machine 1 is prevented from entering from the outside, or fluid (lubricating oil or the like) flowing in the inside is prevented from leaking to the outside as in the first embodiment or more. be able to.

5. Conclusion As described above, according to the present embodiment, it is possible to implement the method for manufacturing the non-contact seal structure 2 that can be manufactured in a shorter time and can be manufactured at a lower cost than ever before.

  The manufacturing method includes a work fixing process (step S1), a rotating process (step S2), and a cutting process (steps S3 and S4). In the work fixing process (step S1), a predetermined rotating shaft is used. The work W is rotatably fixed around the first rotation axis X, and in the rotating step (step S2), the work W is rotated around the first rotation axis X and the tool 5 having the cutting edges 51, 51, 51, 51. Is rotated about a second rotation axis Z different from the first rotation axis X, and in the cutting process (steps S3 and S4), at least one of the positions of the work W and the tool 5 is displaced to move the work W and the tool 5 together. The non-contact seal structure 2 having the spiral structure 21 is formed by contacting and cutting the outer peripheral side surface W0 or the end surface of the work W. The spiral structure 21 includes the spiral convex portion 23 and the spiral concave portion. And a 2, the rotation process (step S2) is continuously carried out during the cutting process (step S3, S4).

  In addition, it is possible to implement the rotary machine 1 including the non-contact seal structure 2 that can be manufactured in a shorter time and can be manufactured at a lower cost than ever before.

  The rotary machine 1 includes a housing 3 and a non-contact seal structure 2, and the housing 3 is provided so as to cover the non-contact seal structure 2 with a gap S between the non-contact seal structure 2 and the non-contact seal structure 2. The non-contact seal structure 2 is configured to be rotatable about a predetermined rotation axis X and has a spiral structure 21 on an outer peripheral side surface 20 thereof. The spiral structure 21 includes a spiral projection 23 and a spiral recess. 22 and the spiral recess 22 has a height difference (height a) which is periodically formed in the extending direction (P direction) thereof, and a gap is formed during rotation of the non-contact seal structure 2. The airflow AF is generated from the inside to the outside of S or from the outside to the inside.

  Lastly, various embodiments according to the present invention have been described, but these are presented as examples and are not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. The embodiment and its modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

1: rotary machine 2: non-contact seal structure 20: outer peripheral side face 21: spiral structure 22: spiral concave part 23: spiral convex part 3: housing 5: tool 51: cutting edge a: height P: direction S: Gap W: Work X: Rotation axis Z: Rotation axis α: Decimal part

Claims (7)

A method for manufacturing a non-contact seal structure, comprising:
It has a work fixing process, a rotating process, and a cutting process.
In the work fixing step, the work is rotatably fixed around a first rotation axis that is a predetermined rotation axis,
In the rotating step, while rotating the work around the first rotation axis, a tool having a cutting edge is rotated around a second rotation axis different from the first rotation axis,
In the cutting step,
Displace at least one position of the work and the tool,
A non-contact seal structure having a spiral structure is formed by bringing the work and the tool into contact with each other and cutting the outer peripheral side surface or the end surface of the work, and the spiral structure has a spiral convex portion and a spiral. And a concave portion,
The rotating step is continuously performed during the cutting step,
Production method. The manufacturing method according to claim 1,
In a side view of the non-contact seal structure, the angle formed by the spiral protrusion and the first rotation axis is defined as θ,
Implemented so as to satisfy 10 degrees ≤ θ ≤ 80 degrees,
Production method. In the manufacturing method according to claim 1 or 2,
The spiral recess has a height difference that is periodically formed in its extending direction,
Production method. The manufacturing method according to any one of claims 1 to 3,
When the number of revolutions of the work per unit time is defined as n_1, the number of revolutions of the tool per unit time is defined as n_2, and the decimal part of the value of n_2 / n_1 is defined as α,
It is performed so that α ≠ 0 and α ≠ 0.5 are satisfied,
Production method. The manufacturing method according to claim 4,
0.03 ≦ α ≦ 0.47 or 0.53 ≦ α ≦ 0.97 is satisfied,
Production method. The manufacturing method according to any one of claims 1 to 5,
The first rotation axis or the predetermined straight line is implemented so as to be orthogonal to the second rotation axis,
The predetermined straight line is a straight line that is parallel to the first rotation axis and intersects the second rotation axis.
Production method. A rotating machine,
A housing and a non-contact seal structure,
The housing is provided so as to cover the non-contact seal structure while having a gap with the non-contact seal structure.
The non-contact seal structure,
It is configured to be rotatable about a predetermined rotation axis and has a spiral structure on its outer peripheral side surface or end face, and the spiral structure has a spiral convex portion and a spiral concave portion, and the spiral concave portion is , Having a height difference periodically formed in its extending direction,
During rotation of the non-contact seal structure, an air flow is generated from the inside to the outside of the gap or from the outside to the inside.
Rotating machine.