Method for producing porous member, fan, and constituent member

Abstract

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

Description

Porous member manufacturing method, fan, and component

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

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

[0003] Japanese Unexamined Patent Publication No. 7-168577

[0004] One method for obtaining resin particles before filling a mold is to crush 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 molded body, it is preferable that each void in the porous molded body is formed to a uniform size. However, the size of the voids in the porous molded body obtained by crushing 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 that reduces variations in pore size.

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

[0007] In the first aspect, compared to a manufacturing method in which resin pellets are crushed and sieved, the size of the resin member (60) after cutting can be made uniform, thereby reducing variation in the size of the voids formed in the porous member. In addition, the voids can be formed evenly throughout the porous member.

[0008] A second aspect is the first aspect, wherein in the cutting step, the rod-shaped resin member (60) is cut at a constant first interval, the first interval is the same as the length of the resin member (60) in a width direction perpendicular to the longitudinal direction, and the length of 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 lengths of the resin member (60) in the width direction and the length direction after cutting can be made uniform, thereby reducing variations in the size of the voids formed in the porous member.

[0010] A third aspect is the first or second aspect, wherein 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.

[0011] In the third aspect, by adjusting the length of the resin member (60) to be cut, it is possible to form a gap of a desired size.

[0012] A fourth aspect is a fan including 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, it is possible to manufacture a fan provided with a porous member in which voids are uniformly formed and the voids have a uniform size.

[0014] A fifth aspect is a component for forming an air passage, comprising 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 the pores have a uniform size.

[0016] FIG. 1 is a front view of a fan according to an embodiment. FIG. 2 is a side view of the fan. FIG. 3 is a schematic diagram showing the shape of a resin member according to an embodiment. FIG. 4 is a flowchart showing the flow of a manufacturing method according to an embodiment. FIG. 5 is an electron microscope photograph of a porous member. (a) Porous member manufactured by a manufacturing method according to an embodiment. (b) Porous member manufactured by a conventional manufacturing method. FIG. 6 shows a cross section of a bell mouth and a fan in the direction of the rotation axis. FIG. 7 shows a cross section perpendicular to the direction of the rotation axis of a fan casing and an impeller.

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses. Furthermore, each configuration of the embodiments, modifications, other examples, etc. described below can be combined or partially substituted within the scope of the present invention. Note that "front" and "rear" shown below refer to the directions indicated by the arrows in FIG. 2.

[0018] (1) Overall Configuration of Fan As shown in FIGS. 1 and 2 , the porous member (51) of this embodiment is applied to a propeller-type 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 the driving force of the motor. The fan (26) of this embodiment has one hub (42) and three blades (41). The number of blades is an example and is not limited thereto.

[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 peripheral surface of the hub (42) and are arranged at equal intervals in the circumferential direction. The three blades (41) are arranged 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 edge portions (41a, 41b, 41c, 41d) each having a different shape. The four edge portions (41a, 41b, 41c, 41d) are an inner edge portion (41a), an outer edge portion (41b), a leading edge portion (41c), and a trailing edge portion (41d).

[0021] The inner edge portion (41a) is an edge of the blade (41) that contacts the outer peripheral surface of the hub (42). The inner edge portion (41a) is provided so as to be inclined from the front end to the rear end of the hub (42) with respect to the direction of the rotation axis 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 rotational 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 rotational direction is located forward of one end Q1 of the inner edge portion (41a) in the rotational 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 rotational direction and the other end Q2 of the inner edge portion (41a) in the rotational 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 Section Each blade (41) is provided with a porous section (50). The porous section (50) is made of a porous material with a plurality of continuous fine pores. In this embodiment, the porous section (50) is made of a resin porous member (51) described below. The porous section (50) is provided so as to penetrate the blade (41) in the thickness direction. The porous section (50) is formed in a part of the blade (41). Specifically, when the fan (26) rotates, air flows toward the front of the page. 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 decreases toward the blade, resulting in an uneven velocity distribution. This can cause air separation from the blade, generating noise. The porous member (51) is provided at a position that could cause this separation. The porous section (50) suppresses unevenness in the air velocity distribution on the blade surface, suppressing air separation from the blade (41), thereby reducing noise generation.

[0025] (3) Molding of the Fan 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 Member Next, a manufacturing method of 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 the 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 this cross-sectional circle 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 450 μm or more and 550 μm or less. To manufacture the porous member, a resin member having a single diameter d may be used, or multiple types of resin members having different diameters d may be used.

[0027] As shown in Fig. 4, the method for manufacturing 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 along a direction perpendicular to the longitudinal direction. When the predetermined intervals are defined as first intervals L, the first intervals L are 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 intervals L are the same 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 sequentially collected. In the cutting step, the resin member may be cut one by one, or a bundle of multiple resin members may be cut simultaneously. Considering the amount of resin member fragments obtained in one cut, it is preferable to cut multiple resin members simultaneously.

[0029] The filling step is a step of filling the cut resin material into a mold, which is formed to fit the shape of the porous member (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 step, the resin member after the heating step is cooled, thereby forming a resin part having a desired shape.

[0032] (5) Porous Member Figure 5 shows electron microscope photographs of a porous member manufactured by the method of this embodiment and a porous member manufactured by a conventional method. The temperature conditions in the heating process were the same for both.

[0033] As shown in FIG. 5( a), the porous member (51) manufactured using the rod-shaped resin member (60) has uniformly formed voids and a relatively high porosity. Furthermore, when the tensile strength of the porous member (51) was measured under predetermined conditions, it was found to be 2.7 MPa, which is sufficient 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, the porous member (51) of this embodiment was found to have a noise suppression effect. Furthermore, because the shape of the resin particles in the porous member (51) is largely maintained, a porous member having a desired size of voids and a desired porosity 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 way, a porous member (51) having desired strength and sound-absorbing performance can be manufactured by selecting the rod-shaped resin member (60), and therefore, a porous member (51) suitable for the fan (26) can be manufactured.

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

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

[0036] This allows the size of the resin member (60) after cutting to be uniform, compared to a manufacturing method in which resin pellets are crushed and sieved, thereby reducing variation in the size of the voids formed in the porous member (51). In addition, voids can be formed evenly throughout the porous member (51). Furthermore, because the size of the resin member (60) after cutting 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, thereby shortening the manufacturing process.

[0037] (6-2) Feature 2 In the method for manufacturing 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 a width direction perpendicular to the longitudinal direction.

[0038] This allows the cut resin member (60) to have the same width and length, thereby reducing variations in the 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 voids of a desired size to be formed by adjusting the length of the resin member (60) to be cut. For example, if the size of each void is to be increased, a resin member (60) that is relatively long in the width direction can be selected, and if the size of each void is to be decreased, 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 section of the rod-shaped resin member (60) perpendicular to the longitudinal direction does not have to be circular. The cross section 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 step 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 blades (41) are described as rotor blades. However, the porous member (51) may be provided on stationary blades, which are non-rotating blades.

[0043] As shown in FIG. 6 , the porous member (51) may be provided in a bell mouth (70). The bell mouth (70) shown in FIG. 6 is an example of a component constituting an air passage. The bell mouth (70) is a cylindrical member provided around the fan (26). An air passage is formed between the inner surface of the bell mouth (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 bell mouth (70). The porous portion (50) may be provided on the entire inner surface of the bell mouth (70) or on a part of the inner surface. This prevents the airflow from separating from the inner surface of the bell mouth (70), thereby reducing noise generation.

[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 reducing 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 in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments and modifications may be combined or substituted as appropriate as long as the functionality of the subject matter of the present disclosure is not impaired.

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

[0048] 26 Fan 41 Blade 51 Porous member 60 Resin member 70 Bell mouth (component) 95 Peripheral wall (component)

Claims

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

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

3. The method for producing a porous member according to claim 1 or 2, wherein 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.

4. A fan having a blade provided with a porous member manufactured by the manufacturing method according to any one of claims 1 to 3.

5. A component constituting an air passage, comprising a porous member (51) manufactured by the manufacturing method according to any one of claims 1 to 3.

Images