Propeller with rough blades and manufacturing method thereof

Abstract

The invention provides a manufacturing method of a propeller, which comprises the following steps of: casting a propeller rough blank with a hub part and a plurality of blades extending outwards from the hub part, and carrying out rough slinging and fine slinging on the propeller rough blank, and performing bead beating treatment on the hub part of the propeller rough blank and the surfaces of the blades by using a plurality of stainless steel balls, so that the blades have rough surfaces. According to the manufacturing method provided by the invention, the fatigue strength of the blade can be enhanced, and a plurality of slinging and polishing processes required by a traditional manufacturing method are reduced, so that the production cost of the propeller is reduced.

Description

Technical Field

[0001] The present invention relates to a propeller, in particular to a propeller with rough blades and a manufacturing method thereof. The manufactured propeller has the dual effects of improving the fatigue strength of the blades and reducing the production cost of the propeller. Background Art

[0002] The manufacturing method of traditional marine propellers usually includes multiple processing steps such as casting, coarse sandblasting, multiple fine sandblasting, and cloth wheel polishing to obtain propellers with smooth blade surfaces.

[0003] However, manufacturing propellers with smooth surfaces requires numerous and complex machining steps, resulting in low production efficiency. Furthermore, after a period of operation, smooth propellers will experience cyclical stresses that can lead to fatigue failure, shortening their service life. In other words, conventional marine propeller manufacturing methods still need improvement. Summary of the Invention

[0004] The object of the present invention is to provide a marine propeller and a manufacturing method thereof. The blades of the manufactured propeller have a rough surface, which can reduce the multiple sandblasting and polishing processes required by the existing manufacturing method, reduce the production cost of the propeller and increase the fatigue strength of the blades.

[0005] To achieve the aforementioned objectives, the present invention provides a propeller manufacturing method, which primarily involves performing surface treatments such as coarse and fine sandblasting on a cast propeller blank, followed by a shot peening process to create a roughened surface on the blades. This improves the blade's surface roughness and fatigue strength, while also reducing the multiple sandblasting and polishing steps required by existing manufacturing methods, thereby lowering propeller production costs.

[0006] The detailed structure, features, manufacturing, assembly, and use of the propeller with roughened blades and the manufacturing method thereof provided by the present invention will be described in the detailed description of the embodiments that follow. However, those skilled in the art will appreciate that such detailed description and the specific embodiments listed for implementing the present invention are merely illustrative of the present invention and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0008] Figure 1 A perspective view of a propeller with rough blades provided in accordance with a first embodiment of the present invention;

[0009] Figure 2A block diagram of a method for manufacturing a propeller according to a first embodiment of the present invention;

[0010] Figure 3 Test report information for a propeller manufactured using the manufacturing method provided in an embodiment of the present invention;

[0011] Figure 4 This is a test report, wherein Test 4 is a propeller manufactured by the manufacturing method provided in an embodiment of the present invention, and Test 5 is a propeller manufactured by a traditional polishing process.

[0012] In the above drawings, the meanings of the reference numerals are as follows:

[0013] 1. Propeller;

[0014] 2. Hub;

[0015] 3. Paddle blades;

[0016] 6. Surface. DETAILED DESCRIPTION

[0017] First, it should be noted that the technical features provided by this invention are not limited to the specific structures, uses, and applications described in the embodiments. The terms used in this description are illustrative and readily understood by persons of ordinary skill in the art. Directional terms such as "front, up, down, back, left, right, top, bottom, inside, and outside" mentioned in this specification are merely illustrative and based on normal usage directions, and are not intended to limit the scope of the claims.

[0018] According to a preferred embodiment of the present invention, the manufacturing method provided by the present invention is mainly to manufacture Figure 1 The propeller 1 shown in FIG. 1 has a hub 2 and a plurality of blades 3 extending outward from the hub 2. Figure 2 As shown, the manufacturing method provided by the present invention mainly involves the following steps: a) casting a propeller blank having a hub and a plurality of blades extending outward from the hub, b) performing a coarse sandblasting surface treatment on the propeller blank, c) performing a fine sandblasting surface treatment on the propeller blank, d) using stainless steel balls with a diameter of 0.3 mm to 0.5 mm to perform a high-speed and high-pressure impact on the surfaces of the blades and the hub, that is, performing a shot peening treatment on the surfaces of the blades and the hub, so that the blades and the hub have a significantly roughened surface 6 to improve the fatigue strength of the blades, and d) completing the following steps: Figure 1The propeller 1 shown. The propeller thus produced can have fatigue strength increased by more than 30%. The manufacturing method of the present invention can reduce the multiple sandblasting and polishing processes required for traditional processing, thereby reducing costs. Secondly, in the shot peening step, the stainless steel balls hit the surfaces of the blades 3 and the hub 2 in various directions, and a plurality of indentations and relative protrusions are generated on the aforementioned surfaces, thereby increasing the roughness of the aforementioned surfaces. Optionally, the manufacturing method provided by the present invention may further include: a step of polishing the surfaces of the blades 3 and the hub 2 after the shot peening treatment using a fine grinding wheel to make the aforementioned surfaces smoother.

[0019] The surface of the blade treated by the manufacturing method provided by the present invention is different from the surface of the propeller blade produced by the traditional polishing process. The surface of the blade treated by the manufacturing method provided by the present invention is smooth to the touch, and when the surface is magnified, it presents a concave and convex texture similar to shark skin. For the shot peening treatment, there are no special restrictions on the processing conditions (such as the size, speed, and pressure of the stainless steel balls), as long as the surface of the blade produced can have a surface roughness Ra in the range of 3.0 to 4.0. Compared with propellers manufactured by traditional polishing processes and having a surface roughness Ra generally in the range of 0.1 to 0.2, the propeller 1 of the present invention has a relatively large surface roughness due to the tiny pits on the blade surface. Although theoretically a rougher surface will lead to a thicker boundary layer and increase resistance, a surface with a plurality of pitted textures can suppress the formation of vortices in the wake, thereby reducing resistance. The results of actual ship tests show that the propeller 1 manufactured according to the manufacturing method provided by the present invention has the same maximum speed as the propeller manufactured by the traditional polishing process.

Claims

1. A propeller comprising a hub and a plurality of blades extending from the hub, characterized in that: The blade of the propeller is subjected to external force to form a rough surface with a plurality of pits. 2 . The propeller according to claim 1 , wherein the surface of the blade has a surface roughness between 3.0 and 4.

0.

3. A method for manufacturing a propeller, comprising the following steps: Casting a propeller blank, the propeller blank having a hub and a plurality of blades extending from the hub; Performing coarse sandblasting and fine sandblasting surface treatment on the rough propeller blank; and The hub and blade surfaces of the propeller blank are bead-peened using stainless steel balls to improve the fatigue strength of the blades. 4 . The method for manufacturing a propeller according to claim 3 , wherein the surface of the blade has a surface roughness ranging from 3.0 to 4.

0. 5 . The method for manufacturing a propeller according to claim 3 , further comprising the step of polishing the surfaces of the hub and the blade after the shot peening treatment. 6 . The method for manufacturing a propeller according to claim 3 , wherein the diameter of the stainless steel ball is between 0.3 mm and 0.5 mm.

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