TW202122302A - Injection molded body and method for producing same - Google Patents

Abstract

The present invention provides an injection molded body that can be used as a suspension member of an automobile. The injection-molded body (1) formed from a thermoplastic resin composition has a first support plate section (10), a second support plate section (20), and a plate-like bridge section (30), the planar shape of the injection molded body (1) being substantially H-shaped or substantially U-shaped, and the first support plate section (10), the bridge section (30), and the second support plate section (20) containing a fibrous filler. The fibrous filler contained in the bridge section(30) is dispersed in the lengthwise direction of the bridge section (30) or in a direction inclined with respect to the lengthwise direction of the bridge section (30), and gate connection marks during injection molding remain in the bridge section (30).

Description

Injection molded body and its manufacturing method

The present invention relates to an injection molded body and its manufacturing method. Among several aspects, it can be used as a suspension part of a bicycle.

It is known according to Japanese Patent Application Publication No. 11-255172, Japanese Patent Application Publication No. 2002-264877, Japanese Patent Application Publication No. 2002-523289, Japanese Patent Application Publication No. 2007-506618, Japanese Patent Application Publication No. 2007-530345, etc. There are bicycles equipped with a suspension to absorb the impact of driving on the road.

In addition, in order to reduce the weight of the bicycle itself, it is also known to use fiber reinforced resin (FRP) instead of metal. When FRP is used, durability becomes important. Especially when FRP is used as a suspension part, it is required to have high durability against continuous vibration during driving.

The subject of the present invention is to provide, among several aspects thereof, an injection molded body having high durability when subjected to an impact. In addition, the subject of the present invention is to provide a method of manufacturing such an injection molded body among several other aspects.

According to one example, the present invention provides an injection molded body composed of a thermoplastic resin composition, the planar shape of which is substantially H-shaped or the planar shape is substantially U-shaped, and having: a first supporting plate portion, a second supporting plate portion, and A plate-shaped bridge portion, wherein the second support plate portion and the first support plate portion are arranged with a gap therebetween, and the plate-shaped bridge portion connects the opposing surfaces of the first support plate portion and the second support plate portion to each other, The first support plate portion, the plate-shaped bridge portion, and the second support plate portion contain fibrous fillers, The fibrous filler contained in the plate-shaped bridge portion is dispersed in a direction along the longitudinal direction of the plate-shaped bridge portion or a direction inclined with respect to the longitudinal direction of the plate-shaped bridge portion, At least one of the four surfaces of the above-mentioned plate-shaped bridge portion has a connection trace of a gate during injection molding.

In addition, according to another example, the present invention provides a method for manufacturing an injection molded body composed of a thermoplastic resin composition, which is supplied through an injection molding machine, including a sprue and a runner as required The route is a method of injecting resin from the gate into the mold to produce an injection molded body composed of a thermoplastic resin composition containing fibrous fillers, The gate has a first opening on the runner side and a second opening on the side of the molded body, and the second opening is connected to at least one of the four surfaces corresponding to the plate-shaped bridge portion of the injection molded body The location of the face, When the first opening and the second opening are square or rectangular, respectively, the short side length a1 of the first opening and the short side length b1 of the second opening are a1=b1, and the first opening The long side length a2 and the long side length b2 of the second opening are b2/a2=1.5-20, or the short side length a1 of the first opening and the short side length b1 of the second opening are a1< b1, the long side length a2 of the first opening and the long side length b2 of the second opening are a2<b2, the cross-sectional area s1 of the first opening and the cross-sectional area s2 of the second opening are s2/ s1=2～600; When the first opening and the second opening are circular, elliptical, or oblong, respectively, the minor axis length a3 of the first opening and the minor axis length b3 of the second opening are a3=b3 , The major axis length a4 of the first opening and the major axis length b4 of the second opening are b4/a4=1.5-20, or the shorter of the minor axis length a3 of the first opening and the second opening The axis length b3 is a3<b3, the major axis length a4 of the first opening and the major axis length b4 of the second opening are a4<b4, the cross-sectional area s3 of the first opening and the second opening The cross-sectional area s4 is s4/s3=2～600; When the first opening and the second opening have shapes other than those described above, the cross-sectional area s5 of the first opening and the cross-sectional area s6 of the second opening are s6/s5=2-600.

The injection molded body obtained by the example of the present invention, for example, even when continuous vibration (impact) is applied to the first support plate portion and the second support plate portion, the bridge portion connecting the first support plate portion and the second support plate portion is also It is not easy to break, and the durability is improved.

＜The first injection molded body＞ 1 to 5, some examples of the first injection molded body having a substantially H-shaped planar shape will be described.

The injection molded body 1 shown in FIGS. 1 and 2 has a substantially H-shaped planar shape, and has a first supporting plate portion 10, and a second supporting plate portion 20 arranged at a distance from the first supporting plate portion 10. And a plate-shaped bridge portion 30 that connects the opposing surfaces of the first support plate portion 10 and the second support plate portion 20 to each other. The "substantially H-shape" here means a shape that is the same as or similar to the H-shape. The injection molded body 1 shown in FIGS. 1 and 2 has a shape that is similar to the H-shape.

Although the planar shape of the first support plate portion 10 shown in FIG. 1(a) is rectangular, in other examples, it may also be elliptical, oblong, triangular or similar to these.

The first support plate portion 10 has a first surface 11, a second surface 12 opposite to the first surface 11 in the thickness direction, and four side surfaces between the first surface 11 and the second surface 12. The four side surfaces include a first short-side side surface 13 and a second short-side side surface 14 located at both ends in the longitudinal direction, and a first long-side side surface 15 and a second long-side side surface 16.

The corners formed by connecting the four side surfaces of the first support plate portion 10 to each other or connecting the first surface 11 and the second surface 12 may have a curvature in part or all of it, or may be formed by connecting the corners Part or all of the part is cut so that the angle of the corner becomes an obtuse angle, and part or all of the above-mentioned obtuse angle may be curved.

The four side surfaces of the first support plate portion 10 may partially have convex or concave curved surfaces, respectively.

The first support plate portion 10 may have one or more through holes 40 to 42 for connecting with other members, and may have protrusions (including protrusions with holes) or hooks instead of the through holes 40 to 42.

In the example shown in the figure, the first support plate portion 10 is suitable for the following purposes, that is, the length of the first short side side 13 and the second short side side 14 is greater than the first long side side 15 and the second long side side 16 The width (thickness) of the width (thickness) increases the resistance to the force applied from the longitudinal direction of the first short side surface 13 and the second short side surface 14.

According to the structure and shape of the installation object (such as a bicycle, etc.), as shown in Figure 1(b), the first support plate portion 10 may also have the following shape: at the first bending portion 45 and the second bending portion 46 1 The long side 15 and the second long side 16 are bent (the shape is bent in two or more places according to the situation). Furthermore, in FIG. 1(b), the injection molded body 1 is shown in a shape with a curvature at the end, but it may also be a shape in which the injection molded body of the same shape as in FIG. 1(a) is bent.

In the example shown in FIG. 1(a), the second support plate portion 20 is the same as the first support plate portion 10, and the planar shape is rectangular, but in other examples, it may be elliptical, oval, Triangular or similar shapes, etc.

The second support plate portion 20 has a first surface 21, a second surface 22 opposite to the first surface 21 in the thickness direction, and four side surfaces between the first surface 21 and the second surface 22. The four side surfaces include a first short side surface 23 and a second short side surface 24 located at both ends in the longitudinal direction, and a first long side surface 25 and a second long side surface 26.

The corners formed by connecting the four side surfaces of the second support plate portion 20 to each other, or connecting to the first surface 21 and the second surface 22 may have a curvature in part or all of it, or may be formed by connecting the corners Part or all of the part is cut so that the angle of the corner becomes an obtuse angle, and part or all of the above-mentioned obtuse angle may be curved.

The four side surfaces of the second support plate portion 20 may partially have convex or concave curved surfaces, respectively.

The second support plate portion 20 may have one or more through holes 40 to 42 for connecting with other members, and may have protrusions (including protrusions with holes) or hooks instead of the through holes 40 to 42.

In the example shown in the figure, the second supporting plate portion 20 is suitable for the following purposes, that is, the length of the first short side 23 and the second short side 24 is greater than the first long side 25 and the second long side 26 The width (thickness) of the width (thickness) increases the resistance to the force applied from the longitudinal direction of the first short-side side surface 23 and the second short-side side surface 24.

As shown in Figure 1(b), depending on the structure and shape of the installation object (such as a bicycle, etc.), the second support plate portion 20 may also have the following shape: at the first bending portion 45 and the second bending portion 46 1 The long side side 25 and the second long side side 26 are bent (a shape that is bent in two or more places depending on the situation). Furthermore, in Fig. 1(b), the injection molded body is represented by a shape with a curvature at the end, but it may also be a shape in which the injection molded body of the same shape as in Fig. 1(a) is bent.

In the example shown in Fig. 1(a) and Fig. 2, the first support plate portion 10 and the second support plate portion 20 have the same thickness, the same shape, and the same size. However, depending on the application, any of the thickness, shape, and size They can also be different. Also, in the example shown in the figure, the first support plate portion 10 and the second support plate portion 20 are arranged in parallel, but they do not necessarily have to be parallel. For example, the extension lines of the two can also be arranged in such a way that they intersect at a distant position. Slightly V-shaped.

In the example shown in the figure, the first support plate portion 10 and the second support plate portion 20 are arranged as follows: the second surface 12 and the first surface 21 are spaced apart in a direction orthogonal to the longitudinal direction of each. Opposite. In one example, the first support plate portion 10 and the second support plate portion 20 are arranged in the following manner: the first short side surface 13 of the first support plate portion 10 and the first short side surface 23 of the second support plate portion 20 The direction orthogonal to the longitudinal direction of each is spaced apart and opposed, and the second short side surface 14 of the first support plate portion 10 and the second short side surface 24 of the second support plate portion 20 are at the same length as each The directions orthogonal to each other are opposed to each other at intervals.

According to several examples of the present invention, the interval between the second surface 12 of the first support plate portion 10 and the first surface 21 of the second support plate portion 20 may be equal intervals as a whole, or may be changed according to the application. It is arranged at partially different intervals. That is, the distances between the surfaces facing each other of the first support plate portion 10 and the second support plate portion 20 are equal or partially different. For example, as shown in FIG. 3, the distance between the portion on the side of the first short side surface 13 of the first support plate portion 10 and the portion on the side of the first short side surface 23 of the second support plate portion 20 may be narrowed. Conversely, the local interval between the portion on the side of the second short side surface 14 and the portion on the side of the second short side surface 24 may be narrowed.

According to several examples of the present invention, the plate-shaped bridge portion 30 has a first surface (a surface facing the same side as the first long side surface 15 of FIG. 1(a)) 31 and the first surface 31 in the thickness (t1) direction The second surface on the opposite side (the surface facing the same side as the second long side side 16 of Figure 1(a)) 32, the first side 33, and the first side 33 are opposite to each other in the width (w1) direction The second side 34.

In the example shown in the figure, the first side surface 33 is located facing the same direction as the first short side surface 13 of the first support plate portion 10, and the second side surface 34 is located facing the second side surface of the first support plate portion 10. The position of the short side 14 in the same direction. The first side surface 33 and the second side surface 34 extend between the first surface 31 and the second surface 32, respectively.

The two side surfaces in the length (L1) direction of the plate-shaped bridge portion 30 are connected to the second surface 12 of the first support plate portion 10 and the first surface 21 of the second support plate portion 20. The bridge portion 30 is closer to the first short-side side surfaces 13, 23 than the middle position in the longitudinal direction of each of the second surface 12 (the first support plate portion 10) and the first surface 21 (the second support plate portion 20) , That is, at a position closer to the first short side side 13 and 23 than the middle position, it is connected to the second surface 12 of the first support plate portion 10 and the first surface 21 of the second support plate portion 20, but it can also be connected to The above-mentioned intermediate position may also be connected to the side of the second short-side side surface 14, 24, that is, a position closer to the second short-side side surface 14, 24 than the intermediate position.

In some examples of the present invention, when the plate-shaped bridge portion 30 is connected to the middle position of each of the second surface 12 and the first surface 21 in the longitudinal direction, the planar shape of the injection molded body 1 becomes an H-shape. Furthermore, as described below, the "plate shape" may include curved bridge portions.

In several examples of the present invention, the connection position (first connection position) between the bridge portion 30 and the second surface 12 of the first support plate portion 10, and the position between the bridge portion 30 and the first surface 21 of the second support plate portion 20 The connection position (the second connection position) can be the same position.

In the example shown in Figure 1 (a) and Figure 2, the first support plate portion 10 and the second support plate portion 20 have the same thickness, the same shape and the same size, and the first connection position is from the first support plate portion 10 The distance between the first short side side 13, the second short side side 14, the first long side side 15, and the second long side side 16 to the bridge portion 30, and the second connection position from the second support plate portion 20 The distances from the 1 short side surface 23, the second short side surface 24, the first long side surface 25, and the second long side surface 26 to the bridge portion 30 are the same.

In some examples of the present invention, the thickness (t1) of the bridge portion 30 is preferably 5 mm or more, more preferably 5-30 mm. In some examples of the present invention, the width (w1) of the bridge portion 30 is preferably 5 mm or more, more preferably 5 to 80 mm. In some examples of the present invention, the length (L1) of the bridge portion 30 is preferably 10 mm or more, more preferably 20-120 mm.

In one example, the thickness (t1), width (w1), and length (L1) preferably satisfy the relationship of t1≦w1<L1. Furthermore, in several examples of the present invention, the ratio (w1/t1) of the thickness (t1) to the width (w1) of the bridge portion 30 may be in the range of 1-30, preferably in the range of 1-16, more preferably The range of 1～5.

According to an example of the present invention, the first support plate portion 10, the second support plate portion 20, and the bridge portion 30 contain fibrous fillers.

As shown in FIG. 4, the fibrous filler contained in the bridge portion 30 includes a fibrous filler 51 and/or a fibrous filler 52. The fibrous filler 51 is positioned along the length (L1) of the bridge portion 30. The fibrous filler 52 is aligned and dispersed in the direction (the direction between the first side surface 33 and the second side surface 34), and the fibrous filler 52 is aligned and dispersed in a direction inclined with respect to the length (L1) direction of the plate-shaped bridge portion 30.

According to several examples of the present invention, the alignment ratio or degree of alignment of the fibrous filler in the bridging portion 30 can be determined by the ratio of the fibrous filler present in the same direction as the length of the gate connected to the bridging portion 30 during injection molding. The amount is evaluated. The fiber orientation relative to the elongation direction of the gate is 1 when the fibers are aligned completely parallel to the direction, 0 when the fibers are aligned completely perpendicular, and 1/3 when the fibers are aligned randomly ( 0.33). In one example, in the XYZ polar coordinate system, the orientation degree of a fiber i (the origin of the fiber is at the origin of the coordinate system) relative to the X direction is set to the deflection angle (polar angle) from the Z axis as θ , When the deflection angle (azimuth angle) from the X axis in the XY plane is set to ϕ, it can be ^{expressed by (sinθ·cosϕ) 2.} Regarding the dispersed n fibers, it can be expressed by 1/n×Σ[i ＝1..n](sinθi・cosϕi) ² Perform calculations.

According to the above example, the degree of alignment can be expressed as a value between 0 and 1. The closer the value is to 1, the greater the amount of fibrous filler existing in the direction orthogonal to the length (L1) direction of the bridge 30. The closer the value is to 0, the greater the amount of the fibrous filler aligned in the direction along the length (L1) of the bridge 30 and/or the direction inclined with respect to the length (L1) of the bridge 30.

According to an example of the present invention, in the bridge portion 30, the fiber alignment with respect to the extending direction of the gate can be reduced from 1. According to one example, the average value of the orientation degree of the fibrous filler is preferably 0.60 or less. According to another example, the average value of the orientation degree of the fibrous filler is preferably 0.55 or less. According to another example, the average value of the orientation degree of the fibrous filler is less than 0.55. The average value of the degree of alignment is preferably 0.50 or less. According to one example, the degree of alignment can be evaluated by software simulation.

According to an example of the present invention, at least one of the four surfaces of the first surface 31, the second surface 32, the first side surface 33, and the second side surface 34 of the bridge portion 30 has a connection trace of the gate during injection molding. The connection mark of the gate can be located in the middle of the length direction of each of the first surface 31, the second surface 32, the first side 33, and the second side 34, preferably at the center of the area, but can also be off the center of the area position.

Which side of the four sides will leave the connection mark can be selected according to the purpose of the injection molded body 1. For example, when the injection molded body 1 is installed on an installation object (a bicycle, etc.), by making the above-mentioned connection marks a shadow of other parts so as to improve the appearance of the product, the positional relationship with the above-mentioned other parts can be selected. Which of the four faces will the connection mark remain?

The example of the injection molded body 1A shown in FIG. 5 is the same except that the shape of the bridge portion is different from the injection molded body 1 of the example shown in FIGS. 1(a) and 2. The bridge portion 130 is convexly curved toward the first short-side side surface 13 side of the first support plate portion 10 and the first short-side side surface 23 side of the second support plate portion 20. In the case of the bridge portion 130 that is bent in this way, the length direction of the bridge portion may be the direction shown in L1 of FIG. 5 orthogonal to the first support plate portion 10 and the second support plate portion 20. When the first support plate portion 10 and the second support plate portion 20 are arranged in a slightly V shape as described above, the length direction of the bridge portion can be the same as that of the first support plate portion 10 and the second support plate portion 20 The angles intersect.

In one example, the width (w1) of the bridging portion 130 may be uniform over the entire curved convex shape, and the thickness (t1), width (w1), and length (L1) preferably satisfy the relationship of t1≦w1<L1 . In addition, in several examples of the present invention, the ratio (w1/t1) of the thickness (t1) to the width (w1) of the bridge portion 130 may be in the range of 1-30, preferably in the range of 1-16, more preferably The range of 1～5.

The injection molded body 1A shown in FIG. 5 is the same as the injection molded body 1 shown in the example of FIG. 3, and may be the portion on the first short side surface 13 side of the first supporting plate portion 10 and the second supporting plate portion The space between the part on the side of the first short side 23 of 20 is narrowed, and it may be the part on the side of the second short side 14 of the first support plate 10 and the second short side of the second support plate 20 The interval between the parts on the 24 sides becomes narrower.

The fibrous filler contained in the bridging portion 130 of FIG. 5 is shown in FIG. 6 and includes a fibrous filler 51 and a fibrous filler 52. The fibrous filler 51 is curved along the convex shape of the bridging portion 130. The directions of the surfaces (the first side surface 133 and the second side surface 134) are aligned and dispersed, and the fibrous filler 52 is aligned and dispersed in a direction inclined with respect to the direction of the convex curved surface. The fibrous fillers 51 and 52 are dispersed in the direction along the length L1 of the bridge 130 or in a direction inclined with respect to the length L1 of the bridge 130.

According to a few examples of the present invention, the alignment ratio or the degree of alignment of the fibrous filler in the bridge portion 130 can be evaluated in the same manner as the alignment ratio or degree of the fibrous filler in the bridge portion 30. According to one example, the average value of the orientation degree of the fibrous filler in the bridge portion 130 is preferably 0.60 or less. According to another example, the average value of the orientation degree of the fibrous filler is preferably 0.55 or less. According to another example, The average value of the orientation degree of the fibrous filler is preferably 0.50 or less.

According to an example of the present invention, the injection molded bodies 1 and 1A shown in FIGS. 1 to 5 are obtained by injection molding a thermoplastic resin composition. The thermoplastic resin composition may contain a thermoplastic resin, a fibrous filler, and a well-known resin additive used as needed.

According to a few examples, the thermoplastic resin can be selected from suitable thermoplastic resins according to the purpose of the injection molded body. Examples include: polyamide resins (aliphatic polyamides such as PA6 and PA66, aromatic polyamides), polyamides Copolymers containing styrene units such as styrene, ABS resin, AS resin, polyethylene, copolymers containing ethylene units, polypropylene, copolymers containing propylene units, other polyolefins, polyvinyl chloride, poly Vinylidene chloride, polycarbonate resin, acrylic resin, methacrylic resin, polyester resin, polyacetal resin, polyphenylene sulfide resin.

According to a few examples, as fibrous fillers, organic fibers such as carbon fibers, glass fibers, polyaramid fibers, cellulose fibers, inorganic fibers (excluding glass fibers), metal fibers, etc. can be used, but they are both lightweight and strong. From a viewpoint, carbon fiber is preferable. The content of the fibrous filler in the thermoplastic resin composition can be selected according to the application, and is preferably in the range of 5-50% by mass.

According to a few examples, the thermoplastic resin composition is preferably a cylindrical shape (resin-attached fiber bundle) with a thermoplastic resin attached to the bundled fibrous filler (fiber bundle) and a length of about 3-30 mm. As such resin-attached fiber bundles, the resin-attached fiber bundles described in Japanese Patent No. 5959183 and Japanese Patent No. 6087052 can be used.

Resin-attached fiber bundles include "fiber bundles (resin-impregnated fiber bundles) in a state where the resin penetrates to the center of the fiber bundle (impregnation) and the resin enters the fibers constituting the center of the fiber bundle (resin impregnated fiber bundle)", "only the surface of the fiber bundle Fiber bundles in a resin-covered state (fiber bundles coated with resin surface)", "the intermediate fiber bundles (the surface of the fiber bundle is covered with resin, only near the surface is impregnated with resin, and the resin does not enter the center of the fiber bundle) ( Part of the resin is impregnated with fiber bundles)” and so on. As the resin-impregnated fiber bundle, for example, PLASTRON (trade name) sold by DAICEL POLYMER (Stock) can also be used.

＜The second injection molded body＞ Based on FIGS. 7 and 8, several examples of the second injection molded body having a substantially U-shaped planar shape will be described. The "substantially U-shape" here means a shape that is the same as or similar to the U-shape, and the planar shape of the injection molded body 1B shown in FIGS. 7 and 8 is a shape similar to the U-shape.

The injection molded body 1B shown in FIGS. 7 and 8 may be the following, that is, except that the connecting position of the bridge portion 30 with respect to the first support plate portion 10 and the second support plate portion 20 is different, the planar shape is substantially U Except for the font shape, it has the same material or structure as the injection molded body 1 shown in Figs. 1 and 2 (planar shape is approximately H-shaped).

In the example shown in the figure, the plate-shaped bridge portion 30 connects the first short-side side surface 13 side of the first support plate portion 10 and the first short-side side surface 23 side of the second support plate portion 20, and the first short-side side surface 13. The first side surface 33 and the first short side side surface 23 of the bridge portion are the same plane. The interval between the first support plate portion 10 and the second support plate portion 20 of the portion without the bridge portion 30 may be equal intervals, or the intervals may be partially different.

In the example shown in FIG. 9, the injection molded body 1C is the same except that the shape of the bridge portion is different from the injection molded body 1B of the example shown in FIGS. 7 and 8, but the planar shape is U-shaped. In this example, the shape of the bridge portion 130 may also be the same as the shape of the bridge portion 130 of the injection molded body 1A shown in FIG. 5.

The bridge portion 130 is convexly curved toward the first short-side side surface 13 side of the first support plate portion 10 and the first short-side side surface 23 side of the second support plate portion 20. The plate-shaped bridge portion 130 connects the first short-side side surface 13 side of the first support plate portion 10 and the first short-side side surface 23 side of the second support plate portion 20, and the first short-side side surface 13 and the first short-side side surface 13 of the bridge portion The side surface 133 and the first short side surface 23 may be curved surfaces of the same plane.

According to a few examples, the injection molded bodies 1, 1A to 1C shown in Figs. 1 to 8 can be used as suspension parts for bicycles. For example, by mounting the injection molded body 1 shown in Figs. 1 and 2 on an axle connected to the rear wheel of a bicycle, it can be used as a suspension part of a bicycle to alleviate the impact during driving.

When used as in the above example, when the bicycle is running, the first support plate portion 10 and the second support plate portion 20 are continuously vibrated in the vertical direction. At this time, an extremely large stress is applied to the central portion of the bridge portion 30 connecting the first support plate portion 10 and the second support plate portion 20. However, the fibrous fillers 51, 52 are present along the length direction of the bridge portion 30. The direction or the direction inclined with respect to the longitudinal direction has a large resistance to the above-mentioned stress, so that the bridge portion 30 can be prevented from being damaged, and it can continuously exert an impact absorption effect as a suspension part.

In addition, the injection molded body 1 is an injection molded body composed of a thermoplastic resin composition. Therefore, compared to an injection molded body using a metal such as aluminum, it can easily correspond to a molded body of various shapes. Lightweight can be achieved.

＜Manufacturing method of injection molded body＞ According to several examples of the present invention, the injection molded bodies 1, 1A to 1C can be manufactured by injecting the thermoplastic resin composition from the gate into the mold through the injection molding machine, the resin supply path including the runner and if necessary runners. . In the manufacturing methods of several examples of the present invention, the shape of the gate used and the connection position of the gate with respect to the mold have characteristics. Depending on the injection form, it can be used by connecting a runner and a gate, or it can also be used by connecting a runner, runner, or gate.

In an example shown in Fig. 10(a), the gate 60 has a first opening 61 on the runner side (runner side when there is a runner) and a second opening 62 on the molded body side. The shapes of the first opening 61 and the second opening 62 are preferably the same shape, and may be, for example, a rectangle, an ellipse, an oval, a quadrilateral other than a rectangle, a circle, and other polygons. According to the relationship between the size of the first opening 61 and the size of the second opening 62, the gate 60 of various embodiments as shown below can be used.

In one example, it is the following embodiment, that is, when the first opening 61 and the second opening 62 are square or rectangular, for example, as shown in FIG. 10, the short side length a1 of the first opening 61 and the second opening The short side length b1 of 62 is a1=b1, and the long side length a2 of the first opening 61 and the long side length b2 of the second opening 62 are b2/a2=1.5-20. In some examples of the present invention, b2/a2 is preferably 2-20, more preferably 3-10. Furthermore, in the case of a square, the length of the short side is equal to the length of the long side.

In another example, it is the following embodiment, that is, when the first opening 61 and the second opening 62 are square or rectangular, for example, as shown in FIG. 11, the short side length a1 of the first opening 61 and the second opening The short side length b1 of the portion 62 is a1<b1, the long side length a2 of the first opening 61 and the long side length b2 of the second opening 62 are a2<b2, and the cross-sectional area s1 of the first opening 61 and the second The cross-sectional area s2 of the opening 62 is s2/s1=2-600. In some examples of the present invention, s2/s1 is preferably 2-100, more preferably 3-60. Furthermore, in the case of a square, the length of the short side is equal to the length of the long side.

In another example not shown in the figure, it is the following embodiment, that is, when the first opening and the second opening are circular, elliptical, or oblong, respectively, the diameter or minor axis length of the first opening a3 The diameter or minor axis length b3 of the second opening is a3=b3, and the diameter or major axis length a4 of the first opening and the diameter or major axis length b4 of the second opening are b4/a4=1.5~ 20. In some examples of the present invention, b4/a4 is preferably 2-20, more preferably 3-10. Furthermore, in the case of a circle, the length of the minor axis is equal to the length of the major axis.

In yet another example not shown in the figure, it is the following embodiment, that is, when the first opening and the second opening are circular, elliptical, or oblong, respectively, the minor axis length a3 of the first opening is The minor axis length b3 with the second opening is a3<b3, the major axis length a4 of the first opening and the major axis length b4 of the second opening are a4<b4, and the cross-sectional area of the first opening The cross-sectional area s4 of s3 and the above-mentioned second opening is s4/s3=2-600. In some examples of the present invention, s4/s3 is preferably 2-100, more preferably 3-60. Furthermore, in the case of a circle, the length of the minor axis is equal to the length of the major axis.

Furthermore, in another example not shown in the figure, there is the following embodiment, that is, when the first opening and the second opening have shapes other than those described above, the cross-sectional area s5 of the first opening and the cross-sectional area of the second opening The area s6 is s6/s5=2-600. In some examples of the present invention, s6/s5 is preferably 2-100, more preferably 3-60.

In some examples of the present invention, the gate length (L) is preferably L/a2 of 0.5-10, more preferably 1-5.

In the manufacturing method of the example of the present invention, in order to control the alignment of the fibrous fillers in the bridging portions 30 and 130 as shown in FIG. 4 and FIG. 6, it is preferable to adjust the size of the bridging portions 30 and 130 to the gate 60 The sizes of the first opening 61 and the second opening 62 are related.

When the first opening 61 and the second opening 62 are square or rectangular, respectively, in several examples of the present invention, the thickness (t1), width (w1) and casting of the bridge portion 30 (bridge portion 130) are preferred. The short side length b1 and the long side length b2 of the second opening 62 of the mouth 60 satisfy the relationship of t1/b1=1 to 6, w1/b2=0.2 to 8.

When the first opening and the second opening are respectively circular, elliptical or oblong, in several examples of the present invention, the thickness (t1) and width ( w1) The short axis length b3 and the long axis length b4 of the second opening of the gate satisfy the relationship of t1/b3=1~6, w1/b4=0.2~8.

When the first opening and the second opening have shapes other than the above, for example, when they are square, quadrilateral other than rectangles, or circular shapes other than circles, ellipses, or oblongs, in some examples of the present invention Preferably, the thickness (t1) and width (w1) of the bridge portion 30 (bridge portion 130) and the maximum length Lmax of the above-mentioned quadrilateral or the diameter D of the above-mentioned circular shape satisfy t1/Lmax or D=1～5, w1/ The relationship between Lmax or D=0.2-8.

In some examples of the present invention, the gate 60 can connect the second opening 62 to the first surface 31 (first surface) of the plate-shaped bridge portion 30 (bridge portion 130) corresponding to the injection molded body 1, 1A to 1C. 131), the second surface 32 (second surface 132), the first side surface 33 (first side surface 133), the second side surface 34 (second side surface 134) at least one of the four surfaces of the mold position Injection molding.

In some examples of the present invention, the gate 60 can also connect the second opening 62 to two or more of the above four surfaces for injection molding. In this case, injection molding can be performed at two or more places at the same time.

In several examples of the present invention, the connecting positions of the gate 60 can be the first surface 31 (first surface 131), the second surface 32 (second surface 132), the first side 33 (first side 133), and the The middle position in the length direction of each of the two side surfaces 34 (the second side surface 134) is preferably the area center position, but it is not limited to this.

In some examples of the present invention, the second opening 62 of the gate 60 is connected to the position of the mold corresponding to which of the above four surfaces, according to the gate formed on the injection molded body 1, 1A to 1C Select the connection mark of 60 and the purpose of injection molded body 1, 1A to 1C. For example, when the injection molded body 1 is installed on an installation object (a bicycle, etc.), the connection marks of the gate are made to be shadows of other parts so as not to be seen to improve the appearance of the product. Consider the position of the other parts mentioned above. Relationship and choose which of the four sides to connect to.

By applying the manufacturing method of the example of the present invention, the alignment of the fibrous filler in the bridging portion 30 (bridging portion 130) can be controlled as shown in FIG. 4 or FIG. 2 The stress is concentrated on the bridge 30 (bridge 130) due to the vibration (impact) applied by the support plate 20, and the bridge 30 (bridge 130) is also hard to break. [Example]

Examples 1 to 5, Comparative Examples 1 to 3 An injection molded body 1 having the configuration shown in Fig. 1(a) and Fig. 2 is manufactured. As the thermoplastic resin composition, PLASTRON (resin impregnated fiber bundle; polyamide containing 40% by mass of carbon fiber, PAX-CF40-02 (L9) F01L, length 9 mm) (manufactured by DAICEL POLYMER (stock)) was used.

Connect the second opening of the gate of the size shown in Table 1 to the bridge portion 30 so that the length direction of the second opening is parallel to the first surface 31 and the second surface 32 of the bridge portion 30 The mold part at the middle of the longitudinal direction of the first side surface 33 is injection-molded.

The gate 60 has, for example, the shapes shown in Figs. 10(a) to 10(c), Fig. 11(a), (b), the dimensions (mm) of a1, a2, b1, and b2, and the gate length L( mm) as shown in Table 1. Furthermore, if the gate of Comparative Example 1 (70 of Fig. 12(b)) is applied to Fig. 10, it is a rod gate of a1=a2=b1=b2. The gate of Comparative Example 2 is a shape in which the first opening is larger than the second opening and the gate 60 faces the opposite direction. The gate of Comparative Example 3 is a rod-shaped gate with a rectangular cross section. The dimensions t1, w1, and L1 shown in Fig. 2 of the bridge portion have the values shown in Table 1.

(Injection molding conditions) Injection molding machine: J150EII of Japan Steel Works Material tank temperature: 280℃ Mold temperature: 130℃

[Table 1] position value Example 1 Example 2 Example 3 Example 4 Example 5 Comparative example 1 Comparative example 2 Comparative example 3 Gate (mm) a1 5 5 2 5 5 5 5 5 a2 5 5 5 5 5 5 5 20 b1 5 5 8 8 20 5 2 5 b2 20 60 20 20 20 5 2 20 s2/s1 4 12 16 6.4 16 1 0.16 1 L 25 25 25 25 25 25 25 25 Bridge (mm) t1 15 15 15 15 15 15 15 15 w1 25 25 25 25 25 25 25 25 L1 50 50 50 50 50 50 50 50 The alignment state of carbon fiber ○ ○ ○ ○ ○ X X X

The alignment state of the carbon fiber was evaluated by observing a cross section obtained by dividing the bridging portion 30 into two parts along the length direction at a position of about 1/2 thickness using a microscope (10 times).

In Examples 1 to 5, the amount of carbon fibers existing along the length direction of the bridge portion 30 or the direction inclined with respect to the above-mentioned length direction exceeded half, and the amount of carbon fibers existing in the direction orthogonal to the above-mentioned length direction was less than half. Half (evaluated as ○).

In Comparative Examples 1 to 3, contrary to the results of Examples 1 to 5, the presence of carbon fibers along the length direction of the bridge portion 30 or the direction inclined with respect to the above length direction is less than about half, and more than half of the remaining portion. The amount of carbon fiber exists in the direction orthogonal to the above-mentioned length direction (evaluated as ×).

Test example 1 The alignment state (orientation degree) of the carbon fibers was simulated in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 3. The results are shown in Table 2. The alignment in Table 2 is expressed by the probability of the existence of carbon fibers aligned in the same direction as the lengthwise direction of the gate (the flow direction of resin and carbon fiber during injection molding).

In Table 2, the closer the value is to 1, the more carbon fiber (fibrous filler 53 in Figure 4) exists in the same direction as the lengthwise direction of the gate, and the closer the value is to 0, it means that the The less carbon fiber (fibrous filler 53 in Fig. 4) exists in the same direction as the lengthwise direction of the gate, it is orthogonal or oblique to the lengthwise direction of the gate, that is, the direction along the lengthwise direction of the bridge. Or the amount of carbon fibers (fibrous fillers 51 and 52 in FIG. 4) aligned with respect to the inclined direction increases.

The average value of the whole bridging part in Table 2 is measured when there are more than 30 parts in the area A (5 mm×5 mm) enclosed by a square in Fig. 12 (a) and (b), the largest value from large to small The average value of 5 locations (part 1 of the bridge part to part 5 of the bridge part).

The simulation conditions are as follows. Simulation software: Autodesk Moldflow Insight 2019

[Table 2] Orientation Example 1 Example 2 Example 3 Example 4 Example 5 Comparative example 1 Comparative example 2 Comparative example 3 The average value of the whole bridge 0.48 0.53 0.54 0.52 0.41 0.77 0.69 0.62 Bridge part 1 0.53 0.58 0.60 0.58 0.43 0.86 0.72 0.65 Bridge part 2 0.48 0.53 0.55 0.53 0.41 0.82 0.71 0.64 Bridge part 3 0.48 0.53 0.55 0.53 0.41 0.78 0.70 0.63 Bridge part 4 0.46 0.50 0.51 0.50 0.40 0.72 0.67 0.60 Bridge part 5 0.44 0.49 0.51 0.49 0.40 0.68 0.65 0.57

According to the results of the simulation, it is also clear that in Examples 1 to 5, the ratio of the fibrous fillers 51 and 52 in Fig. 4 is higher, and in Comparative Examples 1 to 3, the ratio is equivalent to the fibrous filler in Fig. 4 The ratio of filler 53 is higher.

Test example 2 For the injection molded body having the configuration shown in FIG. 1(b), which was manufactured in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 3, the simulation of the maximum generated stress in the bridge portion was performed.

In Fig. 1(b), in a state where the through holes 41, 42 of each of the first support plate portion 10 and the second support plate portion 20 are fixed, the center of the through hole 40 and the through hole 42 is drawn The line (reference line X) is calculated from the direction that intersects the reference line X at an angle of 140 degrees (the direction of arrow Y in Figure 1(b)) and pushes up the second short side 14 and the second side at 19.6 MPa (200 kgf) The maximum stress is generated on the upper surface of the bridge portion 30 when the short side side surface 24 is short.

In the calculation, use the simulation software as described above: the fiber orientation data obtained by Autodesk Moldflow Insight 2019 is coupled, and the structure analysis software is used for simulation. As the simulation software for structural analysis, ADVENTURECluster is used. The results are shown in Table 3. The maximum generated stress of Examples 1 to 5 is less than the value of the maximum generated stress of Comparative Examples 1 to 3.

[table 3] Orientation Example 1 Comparative example 1 Example 2 Example 3 Example 4 Example 5 Comparative example 2 Comparative example 3 Maximum generated stress/MPa 120 150 120 115 120 110 150 140

The maximum generated stress of the injection molded body of Example 1 (using gate 60) is 120 MPa, and the maximum generated stress of the injection molded body of Comparative Example 1 (using gate 70) is 150 MPa. The results show that when the second short-side side 14 and the second short-side side 24 are pushed up at 19.6 MPa (200 kgf) in Example 1, the maximum generated stress on the upper surface of the bridge portion 30 is reduced, and the bridge portion is not easily broken. It can be understood in the same way for other examples and comparative examples.

These results can be considered to be caused by the difference in the alignment state of the carbon fibers in the bridging portion. The visual observation of the alignment state of the carbon fibers in Example 1 and Comparative Example 1 corresponds to the results of the simulation test of Test Example 1.

The injection molded body of the example of the present invention is suitable for applications such as continuous application of vibration, for example, can be used as a suspension part of a bicycle.

1,1A,1B,1C: Injection molding 10: The first support board 11, 21, 31, 131: side 1 12, 22, 32: side 2 13,23: 1st short side side 14,24: 2nd short side side 15,25: 1st long side side 16,26: 2nd long side side 20: The second support board 30,130: Bridge 33,133: first side 34,134: second side 40～42: Through hole 45: The first bending part 46: The second bending part 51, 52, 53: Fibrous filler 60, 70: Gate 61: The first opening 62: The second opening

[Fig. 1] Fig. 1(a) is a perspective view of an injection molded body of an example of the present invention, and Fig. 1(b) is a perspective view of an injection molded body of an embodiment different from (a).

[Fig. 2] Fig. 2(a) is a plan view of the injection molded body of Fig. 1, and Fig. 2(b) is a front view viewed from one direction of Fig. 2(a).

[Fig. 3] Fig. 3 is a plan view of an injection molded body of an embodiment different from the injection molded body of Figs. 1 and 2;

[Fig. 4] Fig. 4 is a plan view for explaining the alignment method of the fibrous filler in the bridging part of the injection molded body of Fig. 1 and Fig. 2.

[Fig. 5] Fig. 5 is a plan view of an injection molded body of another embodiment different from Fig. 1. [Fig.

[Fig. 6] Fig. 6 is a plan view for explaining the alignment method of the fibrous filler in the bridge portion of the injection molded body of Fig. 5. [Fig.

[Fig. 7] Fig. 7 is a perspective view of an injection molded body of an embodiment different from the injection molded body of Figs. 1 to 6.

[Fig. 8] Fig. 8 is a plan view of the injection molded body of Fig. 7.

[Fig. 9] Fig. 9 is a plan view of an injection molded body of an embodiment different from the injection molded body of Fig. 8.

[Fig. 10] Fig. 10(a) is a plan view of a gate of an example of the present invention, Fig. 10(b) is a front view of the first opening of the gate of Fig. 10(a), and Fig. 10(c) is Fig. 10 (A) The front view of the second opening of the gate.

[Fig. 11] Fig. 11(a) is a front view of the first opening of the gate of another example of the present invention which is different from Fig. 10, and Fig. 11(b) is the second opening of the gate of Fig. 11(a) Before view.

[Fig. 12] Fig. 12 is an explanatory diagram of the measurement method of Test Example 1. [Fig.

1: Injection molding

10: The first support board

12, 22: Side 2

13,23: 1st short side side

14,24: 2nd short side side

15,25: 1st long side side

16,26: 2nd long side side

20: The second support board

30: Bridge

31: Side 1

33: side 1

34: second side

40~42: Through hole

Claims (8)

An injection molded body composed of a thermoplastic resin composition, the planar shape of which is substantially H-shaped or the planar shape is substantially U-shaped, and has: a first supporting plate portion, a second supporting plate portion, and a plate-shaped bridge portion, the above The second support plate portion and the first support plate portion are arranged with an interval therebetween, and the plate-shaped bridge portion connects the opposing surfaces of the first support plate portion and the second support plate portion to each other, The first support plate portion, the plate-shaped bridge portion, and the second support plate portion contain fibrous fillers, The fibrous filler contained in the plate-shaped bridge portion is dispersed in a direction along the longitudinal direction of the plate-shaped bridge portion or a direction inclined with respect to the longitudinal direction of the plate-shaped bridge portion, At least one of the four surfaces of the above-mentioned plate-shaped bridge portion has a connection trace of a gate during injection molding. Such as the injection molded body composed of a thermoplastic resin composition of claim 1, wherein: The first supporting plate portion has a first short-side side surface and a second short-side side surface located at both ends in the longitudinal direction, The second supporting plate portion has a first short side surface and a second short side surface located at both ends in the longitudinal direction, The first supporting plate portion and the second supporting plate portion are arranged as follows: the first short side side of the first supporting plate portion and the first short side side of the second supporting plate portion are in the longitudinal direction of each Orthogonal directions oppose at intervals; and The first support plate portion and the second support plate portion are arranged in the following manner: the second short side side surface of the first support plate portion and the second short side side surface of the second support plate portion are in the longitudinal direction of each Orthogonal directions oppose at intervals; When the planar shape is substantially H-shaped, the plate-shaped bridge portion is located closer to the first short side side and the first shorter than the intermediate position of the first supporting plate portion and the second supporting plate portion in the longitudinal direction. Side to side, When the planar shape is substantially U-shaped, the plate-shaped bridge portion connects the first short-side side surface of the first support plate portion and the first short-side side surface side of the second support plate portion. Such as claim 1 or 2 of the injection molded body composed of a thermoplastic resin composition, wherein: The plate-shaped bridge portion is convexly curved toward the side of the first short side of the first supporting plate portion and the side of the first short side of the second supporting plate portion, The fibrous filler contained in the plate-shaped bridge portion is dispersed in a direction along the convex curved surface of the plate-shaped bridge portion or a direction inclined with respect to the direction along the convex curved surface. An injection molded body composed of a thermoplastic resin composition according to any one of claims 1 to 3, wherein the thickness (t1) of the plate-shaped bridge portion is 5 mm or more, and the thickness (t1) and the width (w1) are The ratio (w1/t1) is in the range of 1-30. An injection molded body composed of a thermoplastic resin composition according to any one of claims 1 to 4, wherein the surfaces facing each other of the first support plate portion and the second support plate portion are equally spaced, or the space Partially different. An injection molded body composed of a thermoplastic resin composition according to any one of claims 1 to 5, wherein one or both of the first support plate portion and the second support plate portion have one or more With through holes connected with other components, the injection molded body is used as a suspension part of a bicycle. A method for manufacturing an injection molded body composed of a thermoplastic resin composition, which is injected into the mold through an injection molding machine, a resin supply path including a sprue and a runner if necessary Resin, and a method of manufacturing an injection molded body composed of a thermoplastic resin composition in any one of claims 1 to 6 containing fibrous fillers, The gate has a first opening on the runner side and a second opening on the side of the molded body, and the second opening is connected to at least one of the four surfaces corresponding to the plate-shaped bridge portion of the injection molded body The location of the face, Regarding the above gate, When the first opening and the second opening are square or rectangular, respectively, The short side length a1 of the first opening and the short side length b1 of the second opening are a1=b1, the long side length a2 of the first opening and the long side length b2 of the second opening are b2/ a2=1.5～20, or The short side length a1 of the first opening and the short side length b1 of the second opening are a1<b1, and the long side length a2 of the first opening and the long side length b2 of the second opening are a2< b2, the cross-sectional area s1 of the first opening and the cross-sectional area s2 of the second opening are s2/s1=2-600; When the first opening and the second opening are circular, elliptical, or oblong, respectively, The minor axis length a3 of the first opening and the minor axis length b3 of the second opening are a3=b3, the major axis length a4 of the first opening and the major axis length b4 of the second opening are b4/ a4=1.5～20, or The minor axis length a3 of the first opening and the minor axis length b3 of the second opening are a3<b3, and the major axis length a4 of the first opening and the major axis length b4 of the second opening are a4< b4, the cross-sectional area s3 of the first opening and the cross-sectional area s4 of the second opening are s4/s3=2-600; When the first opening and the second opening have shapes other than the above, The cross-sectional area s5 of the first opening and the cross-sectional area s6 of the second opening are s6/s5=2-600. The method for manufacturing an injection molded body composed of a thermoplastic resin composition of claim 7, wherein when the first opening and the second opening are square or rectangular, respectively, the thickness (t1) of the bridge portion, The width (w1) and the short side length b1 and the long side length b2 of the second opening of the gate satisfy the relationship of t1/b1=1~6, w1/b2=0.2-8; When the first opening and the second opening are circular, elliptical, or oblong, respectively, the thickness (t1) and width (w1) of the bridge portion and the minor axis of the second opening of the gate The length b3 and the major axis length b4 satisfy the relationship of t1/b3=1～6, w1/b4=0.2～8; When the first opening and the second opening have shapes other than the above, the thickness (t1) and width (w1) of the bridge portion and the maximum length Lmax or diameter D of the shape satisfy t1/Lmax or D=1 ～5, w1/Lmax or D=0.2～8.

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