Closed impeller and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-11828293-B2
Application number	US-201917311737-A
Country	US
Kind code	B2
Filing date	Nov 26, 2019
Priority date	Dec 10, 2018
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

A closed impeller (1) includes an impeller main body (2), which is composed of an aluminum alloy and has blades (22) that protrude from a hub (21). A shroud (3) covers the blades. The blades and the shroud are joined together by brazed joints (4). The shroud (3) is formed from a brazing sheet (30) that comprises a core material (31), which is composed of an aluminum alloy, and a filler material layer (320), which is disposed on an outermost surface (33) of the shroud that opposes or faces the blades when the shroud is brazed to the blades.

First claim

The invention claimed is:

1. A closed impeller comprising:
an impeller main body, which is composed of an aluminum alloy and comprises a hub part and blade parts that protrude from the hub part;
a shroud, which covers the blade parts; and
brazed joints, which are interposed between the blade parts and the shroud and join the blade parts and the shroud;
wherein the shroud is a brazing sheet that comprises a core material, which is composed of an aluminum alloy, and a filler material, which is disposed on the core material and is present on an outermost surface on a side opposing the blade parts.

2. The closed impeller according to claim 1 , wherein the joint strength of the brazed joints is 150 MPa or higher.

3. The closed impeller according to claim 2 , wherein the brazed joints have a joint strength of 150 MPa or higher.

4. The closed impeller according to claim 3 , wherein the aluminum alloy of the impeller main body is a 6000-series aluminum alloy or a 7000-series aluminum alloy.

5. The closed impeller according to claim 4 , wherein the aluminum alloy of the core material is a 6000-series aluminum alloy or a 7000-series aluminum alloy.

6. The closed impeller according to claim 5 , wherein:
the aluminum alloy of the core material contains Mg: 0.20 mass % or more and less than 1.80 mass %, and
the filler material contains Si: 6 mass % or more and 13 mass % or less.

7. The closed impeller according to claim 6 , wherein:
the blade parts have a helical shape in plan view, and
the shroud has a funnel shape.

8. The closed impeller according to claim 7 , wherein the filler material contains Bi:
0.0050 mass % or more and less than 0.060 mass %.

9. The closed impeller according to claim 1 or 2 , wherein the brazed joints comprise the filler material, which is composed of an aluminum alloy that contains Mg: 0.25 mass % or more.

10. A method of manufacturing the closed impeller according to claim 1 , comprising:
preparing the impeller main body;
preparing the brazing sheet, which comprises: the core material, which is composed of an aluminum alloy that contains Mg: 0.20 mass % or more and less than 1.80 mass %; and a filler-material layer, which is composed of an Al—Si-series alloy, has a thickness of 20-215 μm, and is disposed on the outermost surface;
preparing the shroud by performing forming work on the brazing sheet and disposing the filler-material layer on a surface opposing the blade parts; and
brazing the surface of the shroud opposing the blade parts and the blade parts of the impeller main body in an inert gas without using flux.

11. The method of manufacturing the closed impeller according to claim 10 , wherein:
the brazing sheet comprises the core material, which is composed of an aluminum alloy that contains Mg: 0.30 mass % or more and less than 1.80 mass %, and the filler-material layer, which is layered on the core material, and
a thickness X [μm] of the filler-material layer and an Mg amount Y [mass %] in the core material satisfy either Equation (1) below or Equation (2) below:
Y≥X/ 120(provided that X≥ 36)  (1) or

Y≥ 0.30(provided that X< 36)  (2).

12. The method of manufacturing the closed impeller according to claim 10 , wherein the brazing sheet further comprises an intermediate material, which is composed of an aluminum alloy that contains Mg: 0.80 mass % or more and less than 6.50 mass % and is interposed between the core material and the filler-material layer.

13. The method of manufacturing the closed impeller according to claim 12 , wherein the intermediate material further contains Si: 2.0 mass % or more and 13.0 mass % or less.

14. The method of manufacturing the closed impeller according to claim 4 , wherein the filler-material layer further contains Bi: 0.0050 mass % or more and less than 0.060 mass %.

15. The method of manufacturing the closed impeller according to claim 4 , wherein the brazing is performed by heating the shroud and the impeller main body in a state in which pressure due to the inert gas is controlled to within a range of 1-110,000 Pa.

16. The method of manufacturing the closed impeller according to claim 4 , wherein after the brazing has been performed, a solution treatment is performed on the closed impeller, and then an artificial-aging treatment is performed on the closed impeller.

17. A closed impeller comprising:
an impeller main body, which is composed of an aluminum material and comprises a hub part and blade parts that protrude from the hub part;
a shroud, which is composed of an aluminum material and covers the blade parts; and
brazed joints, which are interposed between the blade parts and the shroud and join the blade parts and the shroud;
wherein the brazed joints comprise a filler material, which is composed of an aluminum alloy that contains Mg: 0.25 mass % or more.

18. A method of manufacturing a closed impeller comprising: an impeller main body, which is composed of an aluminum material and comprises a hub part and blade parts that protrude from the hub part; a shroud, which is composed of an aluminum material and covers the blade parts; and brazed joints, which are interposed between the blade parts and the shroud and join the blade parts and the shroud, the method comprising:
preparing an assembly, which comprises the impeller main body, the shroud that covers the blade parts, and a filler material, which is disposed between the blade parts and the shroud; and
brazing the assembly in an inert gas without using flux.

Assignees

• Daikin Ind Ltd
• Uacj Corp

Inventors

• Okada Tadashi
• Nishimura Kosuke
• Ueda Kaoru
• Itoh Yasunaga

Classifications

• F04D29/28 Primary

  for centrifugal or helico-centrifugal pumps {for radial-flow or helico-centrifugal pumps} · CPC title

• B23K1/0008

  specially adapted for particular articles or work · CPC title

• B23K35/0238

  layered · CPC title

• B23K35/286

  Al as the principal constituent · CPC title

• C22C21/02

  with silicon as the next major constituent · CPC title