JP3354976B2 - Screw rotor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw rotor and a method of manufacturing the same, and more particularly to a screw rotor of a screw fluid machine in which fluid is compressed, pumped or expanded by a pair of male and female rotors meshing with each other, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a screw fluid machine, a pair of male and female screw rotors are driven to rotate in a casing so as to mesh with each other. A fluid is confined and conveyed in an axial direction to an independent space formed between the inner surface of the casing and the fluid, and the fluid is compressed or pumped.

However, in the case of a screw rotor used for a supercharger of an automobile or a compressor of an aircraft, a hollow screw rotor has been used since the demand for weight reduction and reduction of the moment of inertia.
No. is proposed.

[0004] The screw rotor disclosed in Japanese Utility Model Application Laid-Open No. 63-198401 is formed by drawing, extrusion or precision casting.

[0005]

However, the screw rotor manufactured by the above-mentioned drawing and extrusion processes has various problems as listed below. That is, it is impossible to manufacture a rotor having a large torsion angle.
A uniform twist angle cannot be formed and the accuracy is not good.Thickness uniformity cannot be obtained, resulting in a product with poor dynamic balance. However, there is a problem that the material used for the rotor is restricted because of the need for extensibility that cannot be reduced in weight.

On the other hand, screw rotors manufactured by precision casting have problems that they are not suitable for mass production because the manufacturing cost is high, sand removal is difficult and productivity is low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and its object is to eliminate the above-mentioned various disadvantages of the conventional screw rotor and manufacturing method, and to reduce the weight and the moment of inertia. It is an object of the present invention to provide a screw rotor and a method for manufacturing the same, which can reduce the number of screws.

[0008]

According to the present invention, there is provided a screw rotor comprising a rotating shaft and a screw body, wherein the screw body has a through hole through which the rotating shaft is inserted. Have
And the rotating shaft is inserted through the thin plate forming the wall.
Having a through hole and an opening to form the wall body
The rotating shaft is inserted into the thin plate disposed adjacent to the thin plate to be
A through hole and a filling hole,
A thin plate having a portion and a thin plate disposed adjacent to the thin plate are formed by laminating and joining together, and a hollow portion is formed inside the screw body by an opening of the stacked thin plate. is there.

Further, according to the method for manufacturing a screw rotor according to the present invention, in the method for manufacturing a screw rotor comprising a rotating shaft and a screw body, thin plates having openings are laminated and formed by the openings of the laminated thin plates. After filling the powder pressurizing medium into the hollow portion, the thin plates are subjected to HIP treatment and diffusion-bonded to each other.

[0010]

According to the screw rotor of the present invention having the above-described structure, the screw body is formed by laminating thin plates having openings and joining them together, so that a hollow portion can be formed inside the screw body. . Therefore, the screw rotor can be manufactured with a small thickness, and the weight and the moment of inertia can be reduced.

According to the method for manufacturing a screw rotor of the present invention, thin plates having openings are laminated, and a hollow portion formed by the openings of the laminated thin plates is filled with a powder pressurizing medium and then subjected to HIP. Since the screw rotor can be manufactured by performing the treatment, the productivity of the screw rotor is good, mass production is possible, and the production cost is low.
In addition, a screw rotor having a large helix angle can be manufactured, and the accuracy of the screw rotor is improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a screw rotor according to the present invention and a method for manufacturing the same will be described below with reference to FIGS.

FIGS. 1 to 4 show a screw rotor according to an embodiment of the present invention in which thin plates having two protruding portions are stacked. FIG. 1 is a plan view, and FIG. FIG. 3 is a partial sectional front view taken along the ridge line II-II of the top, FIG. 3 is a sectional view taken along the line III-III of FIG. 1, and FIG. 4 is a side view.

The screw rotor 1 comprises a screw body 3 having a helical outer shape and a rotating shaft 2 supporting the screw body 3. The screw body 3 is formed by laminating a large number of thin plates 4 and joining them together as shown in FIG. That is, the thin plate 4 constituting the screw body 3 has a substantially eyebrow shape as shown in FIG. 3, and has openings 5 and 5 therein and a through hole 6 therein. When laminating the thin plates 4, the thin plates 4 are rotated by a slight angle around the center 0 so as to be laminated so that there is a slight phase difference between the adjacent thin plates 4. Thereby, as shown in FIGS. 1 and 4, a spiral screw outer shape in the screw body 3 is formed, and two spiral hollow portions 7 are formed. The rotary shaft 2 is provided in the through hole 6.
Are inserted, and the thin plate 4 and the rotating shaft 2 are joined to each other.

The thin plate 4 on at least one side end of the screw body 3 is formed of a solid material having no openings 5 and 5, and the front end face or the rear end face (or both end faces) of the screw body 3 is formed. ) Is a closed surface.

Next, a method of manufacturing the screw rotor having the above-described configuration will be described with reference to FIGS. First, a predetermined number of thin plates 4A having openings 5, 5 and through holes 6 as shown in FIG. 5 are formed by punching, laser processing, or the like, and without having the openings as shown in FIG. Similarly, a predetermined number of thin plates 4B made of a substantially solid material having only the through holes 6 are formed by punching or laser processing. At the same time as or after the formation of the thin plates 4A, 4B, a pair of positioning holes 8, 8 provided at positions slightly separated from the through holes 6 are formed. Positioning holes 8, 8 formed in each thin plate 4A, 4B
Are different from each other, that is, the angle θ from the reference line V extending vertically through the center 0 to the positioning hole 8 is set so as to increase by a predetermined angle as the layers are stacked. I have. This predetermined angle is an angle obtained by dividing the entire winding angle by the number of stacked layers. For example, if the total winding angle is 250 ° and the number of stacked layers is 250, the angle θ is set to an angle that increases by 1 ° as the layers are stacked. The positioning holes may be one hole instead of a pair. Further, a positioning means such as a key groove provided in the through hole 6 may be used.

Next, a container 10 as shown in FIG. 7 is prepared. In this container 10, a through hole 12 is formed in a bottom plate 11, and two positioning pins 13, 13 are provided upright. Note that the positioning pins 13 and 13 are
Does not penetrate. Then, the rotating shaft 2 is inserted into the through hole 12 of the container 10 having the above-described configuration. As a matter of course, when the number of the positioning holes is one, the number of the positioning pins is one.

Next, as shown in FIG. 8, a predetermined number of thin plates 4B having no openings (see FIG. 6) are laminated, and a thin plate 4A having a predetermined number of openings 5, 5 (see FIG. 8). 5). When laminating the thin plates 4B and 4A, the positioning of the laminated thin plates 4B and 4A is performed by inserting the positioning holes 8 and 8 into the positioning pins 13 and 13, respectively. Finally, as shown in FIG. 9, the thin plate 4 having a small diameter filling hole 9 formed in the thin plate 4B shown in FIG.
C is laminated in a predetermined number. As a result, the external shape of the spiral screw in the screw body 3 is formed, and two spiral hollow portions 7, 7 are formed.

Next, as shown in FIG. 9, the upper lid 16 is covered, and the ceramic powder 15 is put into the hollow portions 7, 7 through the openings 16a formed in the upper lid 16 and the filling holes 9, 9 formed in the thin plate 4C. While filling, the space between the container 10 and the outer periphery of the screw body 3 is filled.

The ceramic powder is made of a material that does not sinter by HIP (Hot Isostatic Pressing). For example, alumina, silicon carbide and the like are suitable. In addition,
This ceramic powder constitutes a powder pressurizing medium for performing HIP processing.

Next, as shown in FIG. 9, a plug 19 is inserted into the opening 16a of the upper lid 16 to perform seal welding, and a contact portion between the upper lid 16 and the container 10 and a contact portion between the upper lid 16 and the rotating shaft 2 are formed. Seal welding or brazing. Before the opening 16a of the upper lid 16 is sealed, a vacuum may be drawn to prevent oxidation and deterioration of the material, and air may be removed as much as possible.

Next, the container 10 sealed as described above is
HIP processing is performed in the IP processing apparatus. Where HI
The P process is a process in which a gas such as argon is used as a pressure medium in a pressure vessel having a built-in heating furnace and a high pressure (several hundred to 200).
0 kgf / cm ² ) and a high temperature (several hundred to 2000 ° C.) synergistic effect. At this time, the temperature of the HIP process,
The pressure and the processing time are appropriately selected according to the material of the thin plate. By the HIP process, the laminated thin plates 4 are diffusion bonded to each other, and the thin plates 4 and the rotating shaft 2 are similarly diffusion bonded. By the diffusion bonding by the HIP processing, the bonded portion is completely adhered and a dense structure is formed.

After the HIP processing is completed, the container 10 and the upper lid 16 are removed by machining or the like. Thereafter, the ceramic powder in the hollow portions 7, 7 is extracted from the filling hole 9 of the thin plate 4C. Finally, the final outer shape processing of the screw body 3 is performed by machining.

Through the above steps, a hollow screw rotor made of a thin plate is formed. After the ceramic powder is extracted from the hollow portion 7, the filling hole 9 may be sealed with a plug or the like. In this embodiment, the wall is formed at the end of the screw rotor. However, the wall may be formed at the middle of the screw rotor by interposing the thin plate 4B at the middle of the laminated thin layers. good. In the case where the thin plate 4B is interposed in the intermediate portion and a wall is formed in the intermediate portion of the screw rotor, the operation of finally extracting the powder pressurized medium from the hollow portion becomes easy.

The screw rotor can also be manufactured by a simple diffusion bonding method in which pressure is applied in one axial direction and diffusion bonding is performed. However, in the simple diffusion bonding method, only the direction perpendicular to the pressing direction can be bonded, so that the laminated thin plates can be easily bonded to each other. After joining by the diffusion joining method, the shaft must be joined separately. On the other hand, if the screw rotor is manufactured by the HIP process, since the HIP process is isotropic pressing, the bonding surfaces in multiple directions can be bonded at a time, and therefore, the laminated thin plate and the shaft can be simultaneously bonded. Can be.

Further, when a screw rotor is manufactured by a simple diffusion bonding method, pressure is applied in a uniaxial direction.
There is a drawback that a gap is easily formed between the thin plates, and this gap portion causes poor bonding. On the other hand, when the screw rotor is manufactured by the HIP process, a gap is hardly formed between the thin plates because the screw rotors are pressed isotropically, and the whole is uniformly joined.

Further, when a screw rotor is manufactured by the simple diffusion bonding method, it is necessary to press and bond the products one by one, but according to the HIP process, a large number of workpieces (screw rotors) are put into a furnace. And can be processed at the same time. In addition, according to the HIP process, a high pressure is uniformly applied to the joint surface, so that a highly reliable screw rotor can be manufactured without using an insert material.

FIG. 10 shows a large number of recesses 2a on the outer circumference of the rotating shaft 2.
An example in which is formed is shown. By forming the concave portion 2a on the outer periphery of the rotary shaft 2 in advance in this way, the inner peripheral surface of the thin plate 4 enters the concave portion 2a by the HIP process, and the bonding strength between the thin plate 4 and the rotary shaft 2 increases. . The recess 2a
May be one.

FIG. 11 is a view showing an example in which thin plates are stacked and positioned without using positioning pins. That is, the jig (jig) 21 composed of a plurality of (2 or 3) divided pieces has an inner peripheral surface formed in a shape corresponding to the outer shape of the screw rotor. Therefore, as shown in FIG. 11, the jig 21 can be formed only by laminating the thin plates 4A and 4B.
Thereby, the outer shape of the screw rotor can be formed. Then, after laminating the thin plates, the jig 21 is removed, the screw main body is put into the container, the ceramic powder is filled between the hollow portion of the screw main body and the container and the screw main body, and the HIP treatment is performed. It can also be manufactured.

FIG. 12 shows a screw rotor formed by laminating thin plates having three leaf projections.
12 (a) is a plan view, and FIG. 12 (b) is XII of FIG. 12 (a).
It is a (b) -XII (b) line sectional view. The manufacturing method is exactly the same as in the above-described embodiment.

As shown in FIG. 13, after the laminated thin plates are sealed with each other by a sealing means, the thin plates can be diffusion bonded to each other and the thin plate and the shaft can be subjected to HIP processing. As a sealing means, metal plating, thermal spraying, CVD (chemical vapor deposition), PVD (ph
Metal coating such as ysical vapor deposition) and welding are suitable. Examples of the plating include nickel plating such as so-called Kanigen plating, immersion in molten aluminum, and the like. The outer surface may be sprayed and the inner surface may be plated. Further, the outer peripheral surface of the laminated thin plates is sealed by a sealing means as shown in FIG. 13, and the hollow portion is filled with ceramic powder and sealed. Then, the thin plates are subjected to HIP treatment and the thin plate and the shaft are diffusion-bonded to each other. You can also.

Although the present invention is applied to the male rotor in the embodiment shown in FIGS. 1 to 13, it is also possible to apply the present invention to the female rotor.

[0033]

As described above, according to the present invention, various effects as listed below can be obtained. The screw rotor can be manufactured with a small thickness, and the weight and the moment of inertia can be reduced. Screw rotors have good productivity and can be mass-produced.
Further, the production cost is low. The precision of the screw rotor is good, and a large torsion angle can be freely obtained. It can be manufactured as an integrated product in which the rotating shaft and the screw body are integrated. There are no restrictions on the material used for the screw rotor. When the powder pressurizing medium is not used after being sealed by the sealing means, it is not necessary to extract the powder pressurizing medium. Further, deformation to the inside of the rotor is avoided, and the accuracy of the product is further improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a screw rotor according to the present invention.

FIG. 2 is a partial sectional front view showing one embodiment of the screw rotor according to the present invention. The partial cross section is a cross section cut along the ridge line II-II at the top of the screw in FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a side view showing one embodiment of the screw rotor according to the present invention.

FIG. 5 is a side view showing a thin plate in one embodiment of the screw rotor according to the present invention.

FIG. 6 is a side view showing a thin plate in one embodiment of the screw rotor according to the present invention.

FIG. 7 is an explanatory view showing one embodiment of a method for manufacturing a screw rotor according to the present invention.

FIG. 8 is an explanatory view showing one embodiment of a method for manufacturing a screw rotor according to the present invention.

FIG. 9 is an explanatory view showing one embodiment of a method for manufacturing a screw rotor according to the present invention.

FIG. 10 is an explanatory view showing another embodiment of the method for manufacturing a screw rotor according to the present invention.

FIG. 11 is an explanatory view showing another embodiment of the method for manufacturing a screw rotor according to the present invention.

FIG. 12 is a view showing another embodiment of the screw rotor according to the present invention, wherein FIG. 12 (a) is a plan view and FIG. 12 (b).
FIG. 13 is a sectional view taken along line XII (b) -XII (b) in FIG.

FIG. 13 is an explanatory view showing still another embodiment of the method for manufacturing a screw rotor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw rotor 2 Rotating shaft 3 Screw main body 4 Thin plate 5 Opening 7 Hollow part 8 Positioning hole 10 Container 13 Positioning pin 15 Ceramic powder 16 Upper lid 21 Jig

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-41634 (JP, A) JP-A-2-112691 (JP, A) JP-A-49-15010 (JP, A) JP-A-2- 221382 (JP, A) JP-A-2-83273 (JP, A) JP-A 1-237083 (JP, A) JP-A 63-177689 (JP, U) JP-A 49-126212 (JP, U) J. 44-25736 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) F01C 1/16 F04C 18/16

Claims (5)

(57) [Claims] 1. A screw rotor comprising a rotating shaft and a screw main body, wherein the screw main body includes the screw main body.
It has a through hole through which the pivot is inserted and forms a wall
And a through-hole and an opening through which the rotating shaft is inserted.
Having and disposed adjacent to the thin plate forming the wall
And a through hole through which the rotating shaft is inserted and a filling hole
Adjacent to the sheet having a hole and having the opening.
A screw rotor formed by laminating and joining thin plates arranged together, and forming a hollow portion inside the screw body by an opening of the laminated thin plate. 2. The method according to claim 1, wherein the sheets are slightly spaced between adjacent sheets.
The screw rotor according to claim 1, wherein the screw rotor is laminated so as to have a phase difference . 3. A method of manufacturing a screw rotor comprising a rotating shaft and a screw body, wherein thin plates having openings are laminated, and a hollow portion formed by the openings of the laminated thin plates is filled with a powder pressurizing medium. A method for manufacturing a screw rotor, wherein the thin plates are subjected to HIP treatment and then diffusion bonded to each other. 4. An HIP process in which the outer surface of the laminated thin plate is covered with a powder pressurizing medium.
A manufacturing method of the screw rotor described. 5. A method for manufacturing a screw rotor comprising a rotating shaft and a screw body, wherein the rotating shaft is inserted
A thin plate having a through hole and forming a wall,
It has a through hole and an opening through which the rotating shaft is inserted.
A thin plate arranged adjacent to a thin plate forming said wall
And a through hole through which the rotating shaft is inserted and a filling hole.
And is disposed adjacent to the thin plate having the opening.
A method for manufacturing a screw rotor, comprising: laminating thin sheets with each other, sealing the stacked thin sheets with each other by a sealing means, performing HIP processing, and diffusion bonding the thin sheets to each other.