JPH11210687A - Impeller with shroud - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an impeller from being subjected to tension in such a way that it can withstand high speed revolution, and enhance the stiffness of whole the structure. SOLUTION: A shroud in a cone shape is formed out of a CFRP laminated plate 12 comprising long fiber CFRP prepreg 11 liminated. An impeller main body 13 having a boss 14 and blades 15, is formed out of short fiber reinforced resin. The shroud 10 is joined with the outer side of the impeller main body 13 so as to be integrated therewith. Since the shroud 10 formed out of the CFRP laminated plate 12 made of longer fibers is higher in stiffness than the impeller main body 13 formed out of short fiber reinforced CFRP, let compression stress be incurred in each blade 15 just because of the difference in stiffness between both of them, by letting the shroud 10 act as a hoop. Besides, a CFRP laminated plate 16 is joined with the base end surface of the boss 14 so as to allow the base end part of the impeller main body 13 to be high in stiffness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impeller with a shroud among centrifugal impellers used for general-purpose compressors and compressors of refrigerators, and more particularly to an impeller with a shroud made of CFRP.

[0002]

2. Description of the Related Art Centrifugal impellers used for general-purpose compressors and compressors of refrigerators include open impellers and impellers with shrouds.

[0003] As shown schematically in Fig. 3, an open impeller is formed so as to expand in diameter from a distal end, which is one end in the axial direction, to a proximal end, which is the other end, and is driven to the shaft center. Boss 3 through which shaft 1 is fixed
And a casing 5 in which the impeller body 2 composed of a plurality of wings 4 integrally formed on the outer peripheral surface of the boss 3 is formed separately.
The impeller body 2 is rotatably driven inside the casing 5 so that the fluid taken in from the distal end portion 6 is pressurized and sent out from the proximal end outer peripheral portion 7. is there.

On the other hand, as shown schematically in FIG. 4, an impeller with a shroud has a ring-shaped shroud 8 concentrically formed on the outer periphery of an impeller body 2 comprising a boss 3 and a wing 4 similar to the open impeller. And the outer peripheral end of the wing 4 of the impeller body 2 is joined to and integrated with the inner side surface of the shroud 8, and the impeller body 2 and the shroud 8 are introduced from the tip 6 so as to rotate integrally. The fluid is guided to the outer peripheral portion 7 on the proximal end side.

[0005] The impeller with a shroud has a smaller flow loss because there is no gap between the blade 4 and the casing 5 as compared with an open impeller without a shroud.
Since the compression efficiency is high, an impeller with a shroud is more effective, and a metal impeller has been used so far.

[0006]

However, in the case of a conventional impeller with a metal shroud, the inner surface of a relatively thick ring-shaped shroud 8 is joined to the outer peripheral end of the thin blade 4. The centrifugal force causes the wing 4
The shroud 8 is larger than the shroud 8. Therefore, when the shroud 8 is rotated at high speed, a large radial tensile stress is generated in the blade 4 due to the centrifugal force of the shroud 8, and the blade 4 may not be able to withstand and break. Therefore, there is a problem that a high-speed rotation speed cannot be obtained and a high pressure ratio cannot be obtained.

[0007] Therefore, the present invention aims to obtain a high pressure ratio (high rotation) with a light weight and high rigidity as a conventional impeller with a shroud as the impeller with a shroud.

[0008]

According to the present invention, in order to solve the above-mentioned problems, a long fiber CFRP prepreg is laminated in a cone shape such that the direction of the long fiber is the circumferential direction or the circumferential direction and the axial direction. A shroud is formed from a cone-shaped CFRP laminated plate, and an impeller body is formed by integrating short-fiber reinforced CFRP with a boss and wings on the outer surface of the boss. The impeller body is coaxial with the inside of the shroud. A configuration is made in which both are integrally formed by being arranged on a core wire.

The shroud reinforced by long fibers has higher rigidity than the impeller body reinforced by short fibers, and this rigidity difference causes a radially outward load due to centrifugal force during rotation. The elongation of the shroud is smaller than that of the impeller body.In particular, since the shroud is made so that the direction of the long fiber is the circumferential direction or the axial direction with the circumferential direction, or the angle is slightly shifted, the elongation in the circumferential direction is small. As it is more restrained, the shroud acts as a backlash against the impeller body that is going to expand,
Since the impeller body pushes the shroud, a radial compressive stress is generated on the blade.

[0010] A CFRP laminate obtained by laminating CFRP prepregs of long fibers so that the directions of the long fibers are different,
With the structure fixed to the base end side surface of the boss of the impeller body, the boss can be prevented from expanding in the radial direction by high-speed rotation with the CFRP laminate, and the rigidity of the base end side of the boss can be increased. it can.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 (a), 1 (b) and 1 (c) show an embodiment of an impeller with a shroud according to the present invention, in which a long fiber CFRP prepreg 11 is formed in a cone shape and the direction of the long fiber 11a is the circumferential direction. Or CFRP laminated board 1 which is laminated so as to be in the circumferential direction and the axial direction and integrally joined together
2, a cone-shaped shroud 10 having high rigidity is formed, and an impeller body 13 made of low-rigidity short-fiber reinforced resin composed of a boss 14 and wings 15 outside the boss 14 is formed by short-fiber reinforced resin. An impeller body 13 made of short fiber reinforced resin is concentrically arranged inside the shroud 10 made of a CFRP laminate, and the outer peripheral end of each wing 15 is joined to the inner surface of the shroud 10 to be integrated,
Make it an impeller with a shroud. Boss 1
4 is a long fiber CFRP prepreg 11
Is assembled and joined to the boss 14 to be integrated.

Next, the method of manufacturing the impeller with a shroud according to the present invention will be described in detail. First, a long-fiber thermoplastic resin CFRP prepreg 11 formed by impregnating a long fiber 11a of a carbon fiber with a thermoplastic resin is used. After winding and laminating the cone-shaped core so that the direction of the fiber is the circumferential direction or the direction of the long fiber 11a is different from the circumferential direction and the axial direction as shown in FIG. A shroud 10 is formed from a cone-shaped CFRP laminate 12 that is melt-hardened.

The CFRP laminate 16 is made of the long fiber 1
Lamination of the CFRP prepreg 11a to form a cone-shaped C
As in the case of making the FRP laminated board 12, the CFRP prepreg 11 is laminated so that the direction of the long fiber is radial and concentric as shown in FIG. I do.

On the other hand, the impeller body 13 composed of the boss 14 and the wing 15 has a complicated shape and the CF of the long fiber 11a is formed.
Since the RP prepreg is difficult to mold, the RP prepreg is molded by injection molding of a short fiber reinforced resin using the same resin as the CFRP prepreg 11 or the like.

Thereafter, the previously formed shroud 10 and the impeller body 13 are placed in a mold having an internal space of a shape obtained by combining the shroud 10 and the impeller body 13. After being assembled and heated and re-melted, the outer peripheral end of the blade 15 is joined to the inner surface of the shroud 10 so that the shroud 10 and the impeller body 13 are integrated, and the base end face of the boss 14 of the impeller body 13 The CFRP laminated plate 16 is joined to be integrated.

After the shroud 10 and the impeller body 13 are integrally formed, a hole 1 is formed in the axial center of the boss 14.
7 is formed so that the drive shaft 1 passes through the hole 17. 18 is a boss 1 for assembling the CFRP laminate 16.
4 is a concave portion formed on the base end face.

The rigidity of the shroud 10 formed by the CFRP laminated plate 12 in which the long fibers CFRP prepregs 11 are laminated so that the direction of the long fibers 11a is the circumferential direction or the axial direction is the impeller body 13 made of short fiber reinforced CFRP.
It is large compared to the rigidity. By the way, the short fiber reinforced CFRP and the long fiber CFRP laminated board are made to have the same density (1.7 kg / cm
When the elastic modulus and the strength in the case of ³ ) were compared, the elastic modulus was 7000 kgf / mm ² for the former 1000 kgf / mm ² and the strength was 10 kgf / mm ² for the former. / mm ² the latter with respect to the 7
It is 0 kgf / mm ² , and it has been found that the latter has higher elastic modulus and strength than the former.

Therefore, the expansion of the shroud 10 due to the centrifugal force during high-speed rotation becomes smaller than the expansion of the low-rigidity impeller body 13 due to the difference in rigidity. The shroud 10 acts as a backlash against the impeller main body 13 that tends to expand due to a radially outward load acting by centrifugal force, and the impeller main body 13 pushes the shroud 10, so that the wing 15 Causes a compressive stress. The amount of generation of the compressive stress of the blade 15 can be reduced by adjusting the thickness of the shroud 10 when laminating the CFRP prepregs 11 by adjusting the rigidity difference between the impeller body 13 and the shroud 11. Therefore, it can withstand high-speed rotation.

Further, by joining the CFRP laminated plate 16 having high rigidity to the base end surface of the boss 14, the boss 1 without the shroud 10 acting as a backlash in the radial direction is provided.
4. The rigidity of the base end of the boss 1 can be increased, and the base end is prevented from extending radially outward during high-speed rotation.
4 can withstand high-speed rotation. Furthermore, the shroud 10 has higher rigidity and lighter weight than the conventional metal shroud, so that the permissible rotation speed is high. Therefore, when the fluid introduced from the distal end portion 6 is compressed and discharged from the proximal end outer peripheral portion 7 as in the conventional case, a high pressure ratio can be obtained by performing high-speed rotation.

Next, FIGS. 2A and 2B show another embodiment of the impeller with a shroud according to the present invention. In the impeller with a CFRP shroud having the same configuration as that of the above embodiment, a shroud 10 is shown. Molding CFRP
The laminated plate 12 is formed by laminating the long fiber CFRP prepreg 11 such that the direction of the fiber of the long fiber CFRP prepreg 11 is slightly shifted from one another. The layers are laminated so that the directions are slightly shifted in angle.

Also in the present embodiment, among the long fibers 11a of the CFRP laminates 12 and 16 which are laminated so that the angles of the fibers are shifted, the long fibers 11a in the direction coinciding with the direction of the load due to the centrifugal force are used. Since the elongation due to the load can be suppressed, the shroud 10 and the CFRP laminate 16 can be made highly rigid.

The present invention is not limited to the above embodiment, and the length and direction of the long fibers 11a are set within a range in which a desired strength can be obtained for the shroud 10 and the CFRP laminate 16. In addition to the method described in the above-described embodiment, only the shroud 10 and the CFRP laminate 16 may be prepared first, and both may be formed in an impeller-shaped mold. After that, the impeller body 13 is injection-molded by injecting the short fiber reinforced resin into the mold, and at the same time, the impeller body 13 is joined to the shroud 10 and the CFRP laminate 16 to be integrated. Good thing,
In addition, it goes without saying that various changes can be made without departing from the scope of the present invention.

[0024]

As described above, according to the impeller with a shroud of the present invention, the following excellent effects are exhibited. (1) A shroud is formed from a cone-shaped CFRP laminate obtained by laminating long-fiber CFRP prepregs in a cone shape such that the direction of the long fibers is the circumferential direction or the axial direction and the short-fiber reinforced CFRP. To form an impeller body that integrates the boss and the wings on the outer surface of the boss, arranges the impeller body on the same axis on the inside of the shroud, and integrally molds both. Therefore, the rigidity of the shroud is made higher than that of the impeller body, and the difference in rigidity makes it possible to reduce the shroud elongation when a load due to centrifugal force is applied as compared with the impeller body. And the impeller body presses the shroud to generate compressive stress on the wings, eliminating the risk of breakage. The wing can withstand high-speed rotation. (2) Since the shroud is lighter and more rigid than a metal shroud, the allowable rotation speed can be increased. (3) By forming the shroud with a CFRP laminate in which the direction of the long fibers is the circumferential direction or the axial direction and the circumferential direction, it is possible to firmly suppress the elongation in the circumferential direction, The rigidity as a hoop can be increased. (4) A CFRP laminated plate formed by laminating CFRP prepregs of long fibers so that the directions of the long fibers are different from each other is fixed to the base end surface of the boss of the impeller body, so that a CFRP laminate having high rigidity is obtained. The plate makes it possible to increase the rigidity of the base end of the impeller body without a shroud acting as a hoop, that is, the base end of the boss. (5) The CFRP laminate is laminated such that the direction of the long fiber is gradually changed at an angle.
The rigidity of the FRP laminate can be increased.

[Brief description of the drawings]

FIG. 1 shows an embodiment of an impeller with a shroud of the present invention, in which (a) is a cut side view, and (b) is a view taken along the line AA of (a), showing the orientation of long fibers in the shroud. (C) is an BB view of (a) showing the orientation of long fibers in the CFRP laminate fixed to the base end face of the boss.

FIG. 2 shows another embodiment of the impeller with a shroud of the present invention, wherein (a) is a view corresponding to FIG. 1 (b),
(B) is a view corresponding to FIG. 1 (c).

FIG. 3 is a schematic sectional side view showing an example of a conventional open impeller.

FIG. 4 is a schematic cut-away side view showing an example of a conventional impeller with a shroud.

[Explanation of symbols]

 Reference Signs List 1 drive shaft 10 shroud 11 long fiber CFRP prepreg 11a long fiber 12 CFRP laminate 13 impeller body 14 boss 15 wing 16 CFRP laminate

Claims (3)

[Claims] 1. A shroud is formed by a cone-shaped CFRP laminate obtained by laminating CFRP prepregs of long fibers in a cone shape such that the direction of the long fibers is the circumferential direction or the axial direction, and the short fibers are formed. A structure in which a boss and an impeller body on the outer surface of the boss are integrally formed by reinforced CFRP, and the impeller body is disposed on the same axis on the inside of the shroud, and both are integrally formed. An impeller with a shroud comprising: 2. The impeller with a shroud according to claim 1, wherein a CFRP laminated plate formed by laminating CFRP prepregs of long fibers so that the directions of the long fibers are different from each other is fixed to the base end side surface of the boss of the impeller body. 3. The impeller with a shroud according to claim 1, wherein the CFRP laminates are laminated so that the direction of the long fiber is changed little by little.