JP3777485B2 - Rotor for rotary fluid machine and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotor of a rotary fluid machine such as a positive displacement vacuum pump and a compressor. More specifically, the present invention is suitable for obtaining a clean vacuum or the like in a dry atmosphere without using oil in a fluid flow path. The present invention relates to a rotor for a rotary fluid machine and a manufacturing method thereof.
[0002]
[Prior art]
In the rotary fluid machine, a pair of rotors having contours of involute curves and cycloid curves are rotated while meshed with each other to pump fluid.
[0003]
Conventionally, the rotor is generally constituted by a solid body. That is, a rotor and a rotating shaft that are formed into a solid integrated type by casting, a solid rotor in which the rotating shaft is cast, or a solid rotor that is fixed to the rotating shaft through a key material, etc. Widely known.
[0004]
However, such a solid rotor cannot be made thin, increases in weight, and has poor workability such as processing and assembly. In addition, the moment of inertia is large, and the rotational acceleration at the time of starting and stopping the rotation is reduced. In addition, when the rotor is broken during rotation, there is a possibility that it may lead to an unexpected situation such as breakage of the casing, and a uniform thickness cannot be obtained, resulting in a problem of poor balance.
[0005]
It is also known to obtain a hollow rotor by laminating and fixing press-punched thin plates, but in this case, it is difficult to fix the thin plates, the production efficiency is poor, and the assembly cost becomes considerably high. . For this reason, for example, Japanese Patent Application Laid-Open No. 7-155102 proposes a hollow chamber formed in each lobe of a rotor that is a cast member.
[0006]
[Problems to be solved by the invention]
However, since the rotor described in Japanese Patent Application Laid-Open No. 7-155102 is formed by casting the rotor, there is a limit to the reduction in thickness, and not only a reduction in weight can be expected. There seems to be a problem with the uniformity of the image.
[0007]
SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a rotor for a rotary fluid machine and a method of manufacturing the same that can reduce the weight of the rotor and reduce the moment of inertia, and can be manufactured at low cost with high productivity.
[0008]
[Means for Solving the Problems]
The invention according to claim 1, by bending along the shell member comprising a plate-shaped metal profile of the rotor lobe, by butting the end face of the shell member set at a position shifted from the apical portion of the lobes A rotor for a rotary fluid machine, comprising: a configured rotor shell; and a connecting portion for attaching the rotor shell to a rotating shaft.
[0009]
According to the present invention configured as described above, the rotor shell is composed of a uniform and relatively small shell member, thereby significantly reducing the weight of the rotor and reducing the moment of inertia to improve the control characteristics. be able to. As a connection part, it is good to form a rotor in a hollow shape as a side plate which covers the opening part of the side surface of a rotor shell. In this case, an air circulation hole may be provided so as not to cause a pressure difference between the inside and outside of the rotor. The side plate also serves as a reinforcement for the rotor shell.
Moreover, by setting the butt portion of the shell member to be shifted from the top end portion of the rotor lobe, the butt portion does not come to the rotor lobe top portion where high flatness is required, and high dimensions are achieved. Accuracy is maintained and exhaust performance is maintained.
[0010]
The invention according to claim 2 is characterized in that the rotor shell is composed of a plurality of shell members each having a shape obtained by dividing the rotor shell in the circumferential direction. It is a rotor. Thereby, since the size of the shell member to be bent is reduced, the processing becomes easier and the processing accuracy is improved.
[0012]
A third aspect of the present invention is the rotor for a rotary fluid machine according to the first aspect, wherein a reinforcing member for preventing deformation of the lobe is provided inside the rotor shell. Thereby, the deformation | transformation of a rotor shell can be prevented and the stable performance can be maintained over a long period of time. The reinforcing member includes, for example, a pin that connects the back surface of the top end of the lobe and the rotating shaft, a plate-shaped member that contacts the entire back surface of the rotor shell attached to the rotating shaft, or a rib having an appropriate shape. Used.
[0013]
It may constitute a rotor by connecting the front SL rotor shell multiple-axis direction. Accordingly, even a rotor having a relatively large axial dimension can be divided and molded individually, so that a tool can be reduced and the molding process can be facilitated. In addition, if a rotor shell unit having the same or different dimensions is manufactured in advance and combined to obtain a rotor having a predetermined dimension, the molding process and the mounting process can be performed separately, thus simplifying the manufacturing process. It becomes.
[0014]
According to a fourth aspect of the present invention, there is provided a molding step of bending a plate-shaped shell member along the contour of a rotor lobe, a forming step of forming a rotor shell by abutting the end faces of the shell member, and the rotor shell. A method for manufacturing a rotor for a rotary fluid machine , comprising: a step of pressurizing a mold in a mold and performing a re-striking; and a step of attaching a rotor shell after re-striking to a rotating shaft. Thereby, compared with the method of the conventional casting etc., productivity, dimensional accuracy, etc. can be improved and a high quality rotor can be provided cheaply.
[0016]
A fifth aspect of the present invention is a rotary pump characterized by incorporating the rotor for a rotary fluid machine according to any one of the first to third aspects into a casing.
[0017]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 1 to 3 show a rotor 1 according to a first embodiment of the present invention, which is applied to a rotor of a two-leaf type rotary pump. The rotor 1 includes a rotor shell 2 formed by bending a plate body such as a stainless steel plate along the profile of two desired lobes L, and a pair of side plates 3 that closes openings at both ends of the rotor shell 2. It is prepared for. As the profile of the lobe L, an involute curve or a cycloid curve is used as in the prior art.
[0018]
In this embodiment, the rotor shell 2 is formed by butting two shell members 4 having the same shape with each other and joining the butted surfaces by welding or the like. The butt joint 5 is set at a position shifted from the top end T of the lobe L of the rotor 1 by an angle θ. The top end T is a portion that is in contact with the inner surface of the casing of the rotary pump or another rotor surface with a predetermined gap, and determines the compression or exhaust performance of the pump. Therefore, by shifting the butt joint portion 5 that is likely to be uneven as in this embodiment from the top end portion T, the dimensional accuracy of this portion is maintained, and the compression or exhaust performance is improved.
[0019]
In this example, the rotor shell 2 is divided to form a shell member 4, which is joined. Accordingly, it is not necessary to bend a large plate material in multiple layers, and the workability and precision of processing can be improved. Further, in this example, the rotor shell 4 is divided into the same number as the number of lobes L of the rotor 1 to form the shell member 4, and the shell member 4 can have the same size and shape. Work and inventory management are simplified. The dividing method is arbitrary, and the rotor shell may be formed by a single shell member having the entire circumference.
[0020]
On the other hand, the side plate 3 is formed by press working or the like so that its outer shape matches the inner shape of the rotor shell 2, and a shaft hole 3 a for inserting the rotating shaft 6 is formed at the center. The shaft hole 3a is formed in an oval shape having a straight portion, and the rotary shaft 6 is fixed to the rotor shell 2 by welding or the like so that the straight portion comes into contact with the notch surface. In the side plate 3, air circulation holes H are formed in order to prevent a pressure difference from being generated in the space inside and outside the rotor 1.
[0021]
Reinforcing pins 8 are disposed between the rotating shaft 6 and the rotor shell 2 at a predetermined interval in the axial direction. The reinforcing pin 8 is fixed to the rotary shaft 6 with a screw or the like at one end thereof, extends in a direction perpendicular to the rotary shaft 6, reaches the top end portion T of the lobe L of the rotor 1, and is joined thereto by welding or the like. ing. In this manner, the rotor shell 2 and the rotary shaft 6 are coupled and reinforced by the reinforcing pins 8, the deformation of the rotor shell 2 can be prevented, the pump performance can be maintained, and the service life can be improved.
[0022]
Next, the manufacturing process of the rotor 1 as described above will be described. First, the molding process of the shell member 4 will be described with reference to FIG. A rectangular flat blank material 9 having a predetermined size as shown in FIG. 4A is prepared by punching or the like of the press, and the blank material 9 is pressed on one side as shown in FIG. Then, the second side is subjected to a second bending process by pressing as shown in FIG. Further, the rotor shell 2 is divided into two parts by sequentially performing a third bending process by a central press as shown in FIG. 4D and a fourth bending process by a press as shown in FIG. The shell member 4 is formed.
[0023]
Next, the two shell members 4 and 4 formed by pressing in this way are butted together while being rotated 180 degrees, and the butted portions are joined by arc welding or the like to form the rotor shell 2 that opens at both ends. To do. In addition, drilling for assembling the reinforcing pins is performed at an appropriate stage from the state of the blank material 9 to the rotor shell 4.
[0024]
Next, in order to determine the shape of the rotor shell 2 as described above, a restructuring process is performed using the die 20 and the punch 21 as shown in FIG. 5 as processing tools. That is, the die 20 and the punch 21 each have the necessary cross-sectional shape of the rotor 1, and when these tools are fitted, a space R for accommodating the rotor shell 2 is formed therebetween. It has become. The punch has a taper whose tip end is tapered, and a step surface 22 is formed on the base end side to pressurize the end face of the rotor shell 2 disposed in the accommodation space.
[0025]
In this restric process, the rotor shell 2 is mounted in the accommodation space R of the die 20, and the punch 21 is lowered and inserted into the rotor shell 2. Here, the punch 21 is smoothly inserted into the rotor shell 2 by the action of the taper, and the rotor shell 2 is pressed toward the die 20. Further, the punch 21 is inserted until the stepped surface comes into contact with the end surface of the rotor shell 2, and in this state, a predetermined pressure is applied so that the wrist-like operation is performed without elastic return (spring back). As a result, the rotor shell 2 is processed with high dimensional accuracy.
[0026]
The side plate 3 is formed by press punching or the like so as to have an outer shape inside the rotor shell 2 and a shaft hole 3a to be attached to the rotary shaft 6, and is subjected to a predetermined machining of the rotary shaft 6 subjected to machining. Join to the position by arc welding. Then, the rotary shaft 6 is inserted into the rotor shell 2 so that the side plates 3 are positioned at both ends of the rotor shell 2, and the contact portions between the rotor shell 2 and the side plates 3 are joined together by laser welding or the like. To do.
[0027]
Thereafter, the reinforcing pin 8 is inserted from the reinforcing pin assembling hole h opened in the rotor shell 2 until the tip of the reinforcing pin 8 reaches the rotating shaft 6, and the reinforcing pin 8 is coupled to the rotating shaft 6 by screwing or the like. And the upper end of this reinforcement pin 8 and the rotor shell 2 are joined by arc welding etc., and the rotating shaft 6 and the rotor 1 are connected with a reinforcement pin, and are reinforced. And the finishing process of this welding part is given.
[0028]
The rotary pump 23 with rotor 1 constructed as described above are shown in FIGS. This is a structure in which two rotating shafts 6 interlocked by a gear 25 are arranged in parallel in a casing 24 and the rotor 1 is attached to each of them by shifting a predetermined angle phase. In this rotary pump, the rotor 1 is hollow, lightweight, and the moment of inertia is small, so that the control responsiveness is good. Further, since the rotor 1 is manufactured at low cost by machining, the manufacturing cost of the pump is also low. Further, since the air circulation hole H is formed in the side plate 3, even when used as a pump, a pressure difference does not occur between the inside and outside of the rotor 1, and deformation of the rotor does not occur.
[0029]
FIG. 8 shows another embodiment of the present invention. Instead of the reinforcing pin 8 used in the embodiment of FIG. 1, the inner shape of the rotor shell 2 (that is, the same shape as the side plate) is shown . In the embodiment, the reinforcing plate 8a divided into two pieces is attached so as to fit the rotating shaft 6 by fitting the inner edge portion into the circumferential groove 26 formed on the outer surface of the rotating shaft. The reinforcing plate 8 a is also formed with an air circulation hole H for preventing a pressure difference between the space inside and outside the rotor 1. The reinforcing plates 8a or the reinforcing plate 8a and the rotor shell 4 are positioned and do not need to be fixed to each other, but are more stably joined by laser welding or the like.
[0030]
By the way, when manufacturing a rotor having a certain axial length in order to manufacture a pump having a large capacity, a large rotor is conventionally manufactured by casting or the like, so that a large mold is required and workability is improved. It was bad. FIG. 9 shows a preferred embodiment in such a case. The rotor shell 2 having a predetermined axial length is prepared as a unit by the method described in FIGS. 4 and 5, and this is necessary in the axial direction. A number of (two in this example) are joined to form the rotor 1 having a desired length.
[0031]
It is desirable to join the joint portions of the rotor shell 2 by welding or the like, but it is not always necessary to join the joint portions so as to ensure the sealing performance of the joint portions. If several units with different lengths are prepared, these units can be combined to form rotors of various lengths. In the above description, the unit composed only of the rotor shell 2 is used. However, for example, one or both sides covered with the side plate 3 may be used as the unit.
[0032]
10 to 12 show another embodiment applied to a so-called three-leaf type rotor 11. In this example, the rotor 11 is mainly composed of a rotor shell 12 having three lobes L and a pair of side plates 13 that close the side openings of the rotor shell 12, and each rotor shell 12 has one lobe. The three shell members 14 forming L are joined together while being abutted against each other.
[0033]
The butt joint 15 of the shell member 12 is located at a position shifted from the top end of the lobe L of the rotor 10 by an angle θ, and the rotor shell 12 is integrally attached to the rotating shaft 16 via the side plate 13, thereby the rotor shell. The hollow portion 17 is formed between the rotary shaft 12 and the rotary shaft 16 as in the above-described embodiment. Each lobe L is reinforced by reinforcing pins 18 that extend radially from the rotary shaft 16 in three directions.
[0034]
【The invention's effect】
As described above, according to the present invention, the rotor can be significantly reduced in weight by forming the rotor shell with a uniform and relatively small shell member. Therefore, when used in a rotary pump or the like, the entire apparatus including the drive unit can be downsized, and the inertial moment can be reduced to improve the control characteristics. In addition, since a mechanical processing step is used without using casting or the like, a high-quality rotor that can be manufactured with high productivity and at low cost and that has high dimensional accuracy can be provided.
[Brief description of the drawings]
FIG. 1 is a partially cut plan view showing a first embodiment of the present invention.
FIG. 2 is a side view of the same.
3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a view similarly showing a bending process of a shell member.
FIG. 5 is a diagram showing a rotor shell forming step.
FIG. 6 is a front sectional view showing an embodiment of a rotary pump using the rotor of the first embodiment.
7 is a plan sectional view of FIG. 6. FIG.
8A is a partially cutaway view showing a rotor according to a second embodiment of the present invention, and FIG. 8B is a view of a reinforcing plate.
FIG. 9 is a partially cutaway view showing a rotor according to a third embodiment of the present invention.
FIG. 10 is a side view showing another embodiment of the present invention.
11 is a cross-sectional view taken along line AA in FIG.
12 is a cross-sectional view showing an example of a rotary pump using the rotor of FIG.
[Explanation of symbols]
1,11 rotor 2,12 rotor shell 3,13 side plate (connecting part)
4, 14 Shell members 5, 15 Butt joints 6, 16 Rotating shafts 7, 17 Hollow portions 8, 18 Reinforcement pins 8 a Reinforcement plate 9 Blank material H Air circulation holes 20, 21 Wrist-like tool 23 Rotary pump 24 Casing

Claims (5)

A rotor shell formed by bending a shell member made of a plate-like metal along the contour of the rotor lobe and abutting the end face of the shell member set at a position shifted from the top end of the lobe, and the rotor shell A rotor for a rotary fluid machine, comprising: a connecting portion that attaches to the rotating shaft.   The rotor for a rotary fluid machine according to claim 1, wherein the rotor shell is composed of a plurality of shell members each having a shape obtained by dividing the rotor shell in a circumferential direction.   The rotor for a rotary fluid machine according to claim 1, wherein a reinforcing member for preventing deformation of the rotor shell is provided inside the rotor shell. A forming step of bending the plate-shaped shell member along the contour of the rotor lobe, a forming step of forming a rotor shell by abutting the end faces of the shell member, and pressing the rotor shell in a mold A method for manufacturing a rotor for a rotary fluid machine, comprising: a step of applying a like, and a step of attaching a rotor shell after re-striking to a rotating shaft.   A rotary pump comprising the rotor for a rotary fluid machine according to any one of claims 1 to 3 incorporated in a casing.

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