Method for producing porous member, fan, and component

Abstract

To provide a method for producing a porous molded body that suppresses variation in void size.SOLUTION: A method for producing a porous member includes: a cutting step in which a rod-like resin member (60) is cut at predetermined intervals along a direction perpendicular to a longitudinal direction; a filling step of filling the cut resin member (60) into a mold; and a heating step of heating the resin member (60) filled in the mold.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a porous member, a fan, and a component. [Background technology]

[0002] The method for producing a porous molded body described in Patent Document 1 includes a step of expanding foamed resin particles filled in a mold by heating them, which causes the foamed resin particles to bond together and form a porous molded body having a predetermined porosity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-168577 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, as a method for obtaining resin particles before filling a mold, there is a method for crushing resin pellets, which are lumps of resin. In this method, resin particles of a predetermined size can be obtained by sieving the crushed resin pellets. From the viewpoint of the strength and sound absorption of the porous molding, it is preferable that each void of the porous molding is formed to a uniform size. However, the size of the voids of the porous molding obtained by the method of crushing the resin pellets is not sufficiently uniform, and there is room for improvement.

[0005] An object of the present disclosure is to provide a method for producing a porous molded body in which variation in pore size is suppressed. [Means for solving the problem]

[0006] The first aspect is a cutting step of cutting the rod-shaped resin member (60) at predetermined intervals along a direction perpendicular to the longitudinal direction; a filling step of filling the cut resin member (60) into a mold; and a heating step of heating the resin member (60) filled in the mold. A method for producing a porous member.

[0007] In the first aspect, the size of the cut resin member (60) can be made uniform, compared to a manufacturing method in which resin pellets are crushed and sieved, so that the variation in size of each void formed in the porous member can be suppressed. In addition, the voids can be formed evenly throughout the porous member.

[0008] The second aspect is the first aspect, In the cutting step, the rod-shaped resin member (60) is cut at a constant first interval, The first interval is equal to the length of the resin member (60) in a width direction perpendicular to the longitudinal direction, The length in the width direction is equal to or greater than the minimum value and equal to or less than the maximum value when the rod-shaped resin member (60) is projected onto a plane parallel to the longitudinal direction of the resin member (60).

[0009] In the second aspect, the resin member 60 after cutting can have uniform width and length, which can reduce variation in size of the voids formed in the porous member.

[0010] The third aspect is the first or second aspect, The length of the rod-shaped resin member (60) in the width direction perpendicular to the longitudinal direction is 300 μm or more and 700 μm or less.

[0011] In the third embodiment, a gap of a desired size can be formed by adjusting the length of the resin member (60) to be cut.

[0012] The fourth aspect is The fan includes blades provided with a porous member manufactured by the manufacturing method according to any one of the first to third aspects.

[0013] In the fourth aspect, a fan can be manufactured that includes a porous member in which voids are uniformly formed and each void has a uniform size.

[0014] The fifth aspect is The component constituting an air passage comprises a porous member (51) manufactured by the manufacturing method according to any one of the first to third aspects.

[0015] In the fifth aspect, a component can be manufactured that includes a porous member in which pores are uniformly formed and each pore has a uniform size. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a front view of a fan according to an embodiment. [Diagram 2] FIG. 2 is a side view of the fan. [Diagram 3] FIG. 3 is a schematic diagram showing the shape of a resin member according to the embodiment. [Figure 4] FIG. 4 is a flowchart showing the flow of the manufacturing method according to the embodiment. [Diagram 5] 5 is an electron microscope photograph of a porous member: (a) a porous member produced by the production method according to the embodiment, and (b) a porous member produced by a conventional production method. [Figure 6] FIG. 6 shows a cross section of the bellmouth and the fan in the direction of the rotation axis. [Figure 7] FIG. 7 shows a cross section perpendicular to the rotation axis direction of the fan casing and the impeller. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is essentially a preferred example, and is not intended to limit the scope of the present invention, its applications, or its uses. Furthermore, each configuration of each embodiment, modification, other example, etc. described below can be combined or partially substituted within the scope in which the present invention can be implemented. Note that "front" and "back" shown below refer to the directions indicated by the arrows shown in FIG. 2.

[0018] (1) Overall configuration of the fan As shown in FIGS. 1 and 2, the porous member (51) of this embodiment is applied to a propeller fan (26) provided in a blower or the like. The fan (26) is directly connected to a motor (not shown). The fan (26) is rotated by being driven by the motor. The fan (26) of this embodiment has one hub (42) and three blades (41). The number of blades is just an example, and there is no limit to the number.

[0019] The hub (42) is a cylindrical member with a closed front end. The hub (42) is disposed coaxially with the drive shaft of the motor. A boss portion (not shown) is formed at the rear end of the hub (42). The drive shaft of the motor is connected to the boss portion.

[0020] The three blades (41) are connected to the outer circumferential surface of the hub (42) and are arranged at equal intervals in the circumferential direction. The three blades (41) are provided so that when the hub (42) rotates in the direction of the arrow in FIG. 1, air flows from the back of the page to the front of the page. Specifically, each blade (41) has four edges (41a, 41b, 41c, 41d) each having a different shape. The four edges (41a, 41b, 41c, 41d) are an inner edge (41a), an outer edge (41b), a leading edge (41c), and a trailing edge (41d).

[0021] The inner edge portion (41a) is an edge of the blade (41) that contacts the outer circumferential surface of the hub (42). The inner edge portion (41a) is provided so as to be inclined with respect to the direction of the rotation axis of the hub (42) from the front end to the rear end of the hub (42).

[0022] The outer edge portion (41b) is an edge facing the inner edge portion (41a). Like the inner edge portion (41a), the outer edge portion (41b) is also inclined with respect to the rotation axis direction of the hub (42). The length of the outer edge portion (41b) is longer than the length of the inner edge portion (41a). One end P1 of the outer edge portion (41b) in the rotation direction is located forward of one end Q1 of the inner edge portion (41a) in the rotation direction. One end P1 of the outer edge portion (41b) is located rearward of the rear end of the hub (42). The other end P2 of the outer edge portion (41b) in the rotation direction and the other end Q2 of the inner edge portion (41a) in the rotation direction are located on approximately the same radial direction of the hub when the fan (26) is viewed from the front.

[0023] The leading edge portion (41c) is the edge on the front side in the direction of rotation of the blade (41). The leading edge portion (41c) connects one end P1 of the outer edge portion (41b) and one end Q1 of the inner edge portion (41a). The leading edge portion (41c) is formed so as to curve backward in the direction of rotation. The trailing edge portion (41d) is the edge on the rear side in the direction of rotation of the blade (41). The trailing edge portion (41d) connects the other end P2 of the outer edge portion (41b) and the other end Q2 of the inner edge portion (41a). The trailing edge portion (41d) is formed so as to curve backward in the direction of rotation.

[0024] (2) Porous part Each blade (41) is provided with a porous portion (50). The porous portion (50) is made of a porous material having a plurality of continuous fine pores. In this embodiment, the porous portion (50) is made of a resin porous member (51) described later. The porous portion (50) is provided so as to penetrate the blade (41) in the thickness direction. The porous portion (50) is formed in a part of the blade (41). Specifically, when the fan (26) rotates, air flows toward the front of the paper. As a result, one surface of the blade (41) becomes a negative pressure surface. The speed of the air flowing along the negative pressure surface becomes slower closer to the blade, and the speed distribution becomes non-uniform. This can cause air to separate from the blade, generating noise. The porous member (51) is provided at a position that can cause the separation. The porous portion (50) suppresses non-uniformity in the speed distribution of the air on the blade surface, and the separation of the air from the blade (41) is suppressed, resulting in suppression of noise generation.

[0025] (3) Fan molding The fan 26 is made of non-porous resin except for the porous portion 50. The fan 26 is molded, for example, by insert molding. Specifically, the porous member 51 is placed at a predetermined position in a mold, and the mold is filled with resin to form the hub 42 and the blades 41 provided with the porous member 51.

[0026] (4) Manufacturing of porous materials Next, a method for manufacturing the porous member (51) constituting the porous portion (50) will be described. As shown in FIG. 3, a rod-shaped resin member (60) is used as a raw material for the porous member (51). The resin member (60) is, for example, a foamed resin. The resin member (60) is an elongated member having a circular cross section perpendicular to its longitudinal direction. The diameter d of the circle of the cross section is synonymous with the length of the resin member (60) in the width direction perpendicular to the longitudinal direction. The diameter d is 300 μm or more and 700 μm or less. The diameter d may be 400 μm or more and 600 μm or less, or may be 450 μm or more and 550 μm or less. A resin member having a single diameter d may be used to manufacture the porous member, or multiple types of resin members having different diameters d may be used.

[0027] As shown in Fig. 4, the method for producing the porous member (51) includes a cutting step, a filling step, a heating step, and a cooling step. The cutting step is a step of cutting a rod-shaped resin member (60) at predetermined intervals in a direction perpendicular to the longitudinal direction. When the predetermined interval is defined as a first interval L, the first interval L is the same as the length of the resin member (60) in the width direction perpendicular to the longitudinal direction (see Fig. 3). In other words, the first interval L is the same length as the diameter d.

[0028] In the cutting step, the resin member is continuously cut at the first interval L. The cut resin member fragments are successively collected. In the cutting step, the resin member may be cut one by one, or a plurality of pieces may be bundled and cut simultaneously. Considering the amount of resin member fragments obtained in one cut, it is preferable to cut a plurality of pieces simultaneously.

[0029] The filling step is a process of filling the cut resin material into a mold. The mold is formed to match the shape of the porous material 51 to be provided on the blade 41.

[0030] In the heating step, the resin member filled in the mold is heated by placing the resin member filled in the mold in a predetermined heating furnace and heating the resin member at a predetermined temperature for a predetermined period of time.

[0031] In the cooling process, the resin member after the heating process is cooled, whereby a resin part having a desired shape is formed.

[0032] (5) Porous materials 5 is an electron microscope photograph of a porous member produced by the method of the present embodiment and a porous member produced by a conventional method, both of which were produced under the same temperature conditions in the heating step.

[0033] As shown in FIG. 5(a), in the porous member (51) manufactured using the rod-shaped resin member (60), the voids are uniformly formed and the void ratio is relatively high. In addition, when the tensile strength of the porous member (51) was measured under predetermined conditions, it was found to be 2.7 MPa, and the porous member (51) was found to have sufficient strength for use in the fan (26). Furthermore, when the fan (26) equipped with the porous member (51) was rotated at a predetermined rotation speed, the noise suppression effect was examined and found to be -0.4 dB compared to the fan (26) not equipped with the porous member (51). In other words, it was found that the porous member (51) of this embodiment has a noise suppression effect. In addition, since the shape of the resin particles in the porous member (51) is generally maintained, a porous member having voids of a desired size and void ratio can be obtained by adjusting the thickness (size of the cross section perpendicular to the longitudinal direction) of the rod-shaped resin member (60) and the first interval. In this manner, a porous member (51) having desired strength and sound-absorbing performance can be manufactured by selecting the rod-shaped resin member (60), so that a porous member (51) suitable for the fan (26) can be manufactured.

[0034] In contrast, as shown in Figure 5(b), in the conventional method of crushing resin pellets, it was found that the voids were not formed uniformly compared to Figure (a), and the shape of each void was also non-uniform.

[0035] (6) Features (6-1) Feature 1 The manufacturing method of the porous member (51) of this embodiment includes a cutting process of cutting a rod-shaped resin member (60) at predetermined intervals along a direction perpendicular to the longitudinal direction, a filling process of filling a mold with the cut resin member, and a heating process of heating the resin member (60) filled in the mold.

[0036] This allows the size of the cut resin member (60) to be uniform, compared to a manufacturing method in which resin pellets are crushed and sieved, and therefore reduces the variation in size of the voids formed in the porous member (51). In addition, voids can be formed evenly throughout the entire porous member (51). Furthermore, because the size of the cut resin member (60) can be uniform, the amount of resin member (60) that cannot be used in manufacturing and is discarded can be reduced, and sieving is not required, shortening the manufacturing process.

[0037] (6-2) Feature 2 In the manufacturing method of the porous member 51 of this embodiment, the rod-shaped resin member 60 is cut at a constant first interval in the cutting step. The first interval is equal to the length of the resin member 60 in the width direction perpendicular to the longitudinal direction.

[0038] This allows the cut resin member 60 to have uniform width and length, thereby reducing variation in size of the voids formed in the porous member 51.

[0039] (6-3) Feature 3 In this embodiment, the length of the rod-shaped resin member (60) in the width direction perpendicular to the longitudinal direction is 300 μm or more and 700 μm or less. This allows the length of the resin member (60) to be cut to be adjusted to form voids of a desired size. For example, if it is desired to increase the size of each void, a resin member (60) that is relatively long in the width direction can be selected, and if it is desired to decrease the size of each void, a resin member (60) that is relatively short in the width direction can be selected.

[0040] (7) Other embodiments The above embodiment may be configured as follows.

[0041] The cross-sectional shape of the rod-shaped resin member (60) perpendicular to the longitudinal direction does not have to be circular. The cross-sectional shape of the rod-shaped resin member (60) perpendicular to the longitudinal direction may be elliptical or polygonal. In this case, the first interval (length in the width direction) in the cutting process is equal to or greater than the minimum value and equal to or less than the maximum value when the rod-shaped resin member (60) is projected onto a plane parallel to the longitudinal direction of the resin member (60).

[0042] In the above embodiment, the blade (41) has been described as a rotating blade. However, the porous member (51) may be provided on a stationary blade, which is a blade that does not rotate.

[0043] As shown in FIG. 6, the porous member (51) may be provided in a bellmouth (70). The bellmouth (70) shown in FIG. 6 is an example of a component that configures an air passage. The bellmouth (70) is a cylindrical member provided around the fan (26). An air passage is formed between the inner surface of the bellmouth (70) and the blades (41). When the fan (26) rotates, air flowing through the air passage comes into contact with the inner surface of the bellmouth (70). The porous portion (50) may be provided on the entire inner surface of the bellmouth (70) or on a part of the inner surface. This prevents the airflow from separating from the inner surface of the bellmouth (70), thereby suppressing the generation of noise.

[0044] As shown in FIG. 7, the porous member (51) may be provided on a peripheral wall (95) of a fan casing (90). The peripheral wall (95) shown in FIG. 7 is an example of a component constituting an air passage. The fan casing (90) houses an impeller (80). The peripheral wall (95) is disposed inside the fan casing (90) so as to surround the impeller (80). The peripheral wall (95) is formed in a scroll shape. An air passage is formed between the impeller (80) and the peripheral wall (95). When the impeller (80) rotates, air flowing through the air passage comes into contact with the inner surface of the peripheral wall (95). The porous portion (50) may be provided on the entire inner surface of the peripheral wall (95) or on a part of the inner surface. This prevents the airflow from separating from the inner surface of the peripheral wall (95), thereby suppressing noise generation.

[0045] The components (70, 95) are not limited to the bell-mouth (70) or the peripheral wall (95). The components (70, 95) may be any components that form an air passage and come into contact with air flowing through the air passage.

[0046] Although the embodiments and modifications have been described above, it will be understood that various modifications of form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments and modifications may be appropriately combined or substituted as long as the functions of the subject of the present disclosure are not impaired. [Industrial Applicability]

[0047] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for a manufacturing method for a porous member, a fan, and a component member. [Explanation of symbols]

[0048] 26 Fans 41 Wings 51 Porous Materials 60 Resin parts 70 Bell mouth (component) 95 Peripheral wall (component)

Claims

1. a cutting step of cutting the rod-shaped resin member (60) at predetermined intervals along a direction perpendicular to the longitudinal direction; a filling step of filling the cut resin member (60) into a mold; and a heating step of heating the resin member (60) filled in the mold. A method for producing a porous member.

2. In the cutting step, the rod-shaped resin member (60) is cut at constant first intervals, The first interval has the same length as a width direction perpendicular to the longitudinal direction of the resin member (60), The length in the width direction is equal to or greater than the minimum value and equal to or less than the maximum value when the rod-shaped resin member (60) is projected onto a plane parallel to the longitudinal direction of the resin member (60). A method for producing the porous member according to claim 1 .

3. The length of the rod-shaped resin member (60) in a width direction perpendicular to the longitudinal direction is 300 μm or more and 700 μm or less. A method for producing the porous member according to claim 1 or 2.

4. A fan having a blade provided with a porous member manufactured by the manufacturing method according to claim 1 or 2.

5. A component constituting an air passage, comprising a porous member (51) manufactured by the manufacturing method according to claim 1 or 2.

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