Composite structure rotating body and resin molded body

Abstract

A composite structure gear is provided with an annular resin molded body including reinforcing fibers and a resin and having a toothed profile formed on the outer periphery, an annular metal bush, and a coupling resin member that connects the resin molded body and the metal bush. In the resin molded body, a plurality of recessed regions are formed at predetermined intervals in the circumferential direction, and the recessed regions are provided with thin parts where recesses are formed on both surfaces of the resin molded body in the thickness direction. In the recessed regions, the total value of the depths of the recesses on both surfaces is less than the thickness of the thin parts.

Description

Composite structure rotating body and resin molded body

[0001] One aspect of the present invention relates to a composite structure rotating body and a resin molded body.

[0002] Patent Document 1 describes a resin composite structure rotor in which teeth are formed by impregnating a reinforcing fiber base material with resin.

[0003] Japanese Patent Application Laid-Open No. 2001-295913

[0004] Here, in the above-mentioned resin composite structure rotating body, during molding, it may be difficult for the reinforcing fibers to follow some areas of the resin molded body (a molded body containing reinforcing fibers and resin), for example, the convex areas of adjacent uneven shapes (the areas sandwiched between two concave areas).

[0005] One aspect of the present invention has been made in view of the above circumstances, and has an object to provide a composite structure rotating body and a resin molded body in which reinforcing fibers are provided in a well-balanced manner to improve strength.

[0006] A composite structure rotating body according to one embodiment of the present invention comprises an annular resin molded body containing reinforcing fibers and resin and having teeth formed on its outer periphery, an annular metal bushing, and a bonding resin member connecting the resin molded body and the metal bushing, wherein the resin molded body has a plurality of recessed regions formed at predetermined intervals in the circumferential direction, and the recessed regions have thin-walled portions with recesses formed on both sides in the thickness direction of the resin molded body, and in the recessed region, the total depth of the recesses on both sides is smaller than the thickness of the thin-walled portion.

[0007] In one aspect of the present invention, a composite-structure rotating body includes an annular resin molded body having a plurality of recessed regions formed along the circumferential direction. Each recessed region has a thin-walled portion with recesses formed on both sides of the resin molded body in the thickness direction. In each recessed region, the sum of the depths of the recesses on both sides is smaller than the thickness of the thin-walled portion. By forming the recesses shallowly, reinforcing fibers can be appropriately provided in the region between adjacent recessed regions during molding of the resin molded body. In other words, if the recesses are deep, it is difficult to provide reinforcing fibers in the region adjacent to the recessed region. However, by forming the recesses shallow enough that the sum of the depths of the recesses on both sides is smaller than the thickness of the thin-walled portion, reinforcing fibers can be appropriately provided in the region adjacent to the recessed region. This allows reinforcing fibers to be provided in a balanced manner, even in a resin molded body having, for example, continuous recesses and protrusions. While shallow recesses can cause a problem of reduced bonding strength between the resin molded body and the bonding resin member, the reinforcing fibers are appropriately provided in the region adjacent to the recessed region as described above, ensuring strength and appropriately suppressing the reduction in bonding strength. As described above, according to one aspect of the present invention, it is possible to provide a composite structure rotating body having improved strength by providing reinforcing fibers in a well-balanced manner.

[0008] The resin molding according to one aspect of the present invention is an annular resin molding that is connected to a metal bushing by a binder resin member to form a composite structure rotating body, the resin molding comprising a reinforcing fiber and a resin, and a plurality of recessed regions formed at predetermined intervals in the circumferential direction, the recessed regions having thin-walled portions with recesses formed on both sides in the thickness direction, and the sum of the depths of the recesses on both sides of the recessed regions is smaller than the thickness of the thin-walled portions. By configuring the resin molding in this manner, it is possible to provide a composite structure rotating body with improved strength due to the provision of reinforcing fibers in a balanced manner.

[0009] In the composite rotating body or resin molded body according to one aspect of the present invention, the reinforcing fibers may be organic fibers. With this configuration, the strength of the composite rotating body or resin molded body can be appropriately improved.

[0010] In the composite rotating body or resin molded body according to one aspect of the present invention, the reinforcing fibers may be aramid fibers. With this configuration, the strength of the composite rotating body or resin molded body can be appropriately improved.

[0011] In the composite rotating body or resin molded body according to one aspect of the present invention, the length of the region sandwiched between two adjacent recessed regions may be greater than the height in the circumferential direction. With this configuration, the reinforcing fibers can be provided so as to appropriately conform to the region sandwiched between the two recessed regions during molding of the resin molded body.

[0012] In the composite rotating body or resin molded body according to one aspect of the present invention, the length of the region sandwiched between two adjacent recessed regions may be at least twice the height in the circumferential direction. With this configuration, the reinforcing fibers can be provided so as to appropriately conform to the region sandwiched between the two recessed regions during molding of the resin molded body.

[0013] In a composite-structure rotating body or resin-molded body according to one aspect of the present invention, the radial length from the inner peripheral surface of the inner peripheral portion to the outer peripheral surface of the outer peripheral portion of the resin-molded body may be 40 to 50% or 30 to 40% of the radius of the resin-molded body. Because strength is required for the resin-molded body, expensive resins are used. In this regard, by adjusting the amount of the resin-molded body to the minimum necessary volume while ensuring appropriate strength, costs can be reduced while meeting the required strength level.

[0014] In the composite-structure rotating body or resin-molded body according to one aspect of the present invention, the corners on the outer periphery of the recess may be rounded. With this configuration, it is possible to improve the releasability from the mold.

[0015] In the composite rotating body or resin molded body according to one aspect of the present invention, the total amount (volume) of reinforcing fibers contained in the resin molded body may be 40% or more. With this configuration, it is possible to impart appropriate strength to the resin molded body.

[0016] According to one aspect of the present invention, it is possible to provide a composite structure rotating body and a resin molded body in which reinforcing fibers are provided in a well-balanced manner to improve strength.

[0017] FIG. 1 is a front view and a cross-sectional view of a composite structure gear according to an embodiment. FIG. 2 is a front view and a cross-sectional view of a resin molded body included in the composite structure gear of FIG. 1. FIG. 3 is a diagram illustrating a molding method. FIG. 4 is a diagram illustrating a molding method. FIG. 5 is a diagram illustrating the state of reinforcing fibers when compressed by mold clamping. FIG. 6 is a cross-sectional view of a composite structure gear according to a comparative example. FIG. 7 is a cross-sectional view of a resin molded body included in the composite structure gear of FIG. 6. FIG. 8 is a diagram illustrating the state of reinforcing fibers when compressed by mold clamping, for a resin molded body according to a comparative example. FIG. 9 is a front view and a cross-sectional view of a composite structure gear according to a modified example. FIG. 10 is a front view and a cross-sectional view of a resin molded body included in the composite structure gear of FIG. 9.

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0019] FIG. 1 is a front view (FIG. 1(a)) and a cross-sectional view (FIG. 1(b)) of a composite structure gear according to an embodiment. As shown in FIGS. 1(a) and 1(b), the composite structure gear 1 is a so-called hybrid gear made of resin and metal, and is used, for example, as a gear for vehicles and industrial applications. The composite structure gear 1 may also be a composite structure rotating body including a metal bushing 3, a resin molded body 5, and a binding resin member 7.

[0020] The metal bushing 3 is a component that is attached to, for example, a rotating shaft (not shown). As shown in Figures 1(a) and 1(b), the metal bushing 3 is annular. The metal bushing 3 is formed of a metal such as stainless steel. A through hole 3h is provided in the metal bushing 3. The through hole 3h passes through the metal bushing 3 in the axial direction. A rotating shaft is inserted into the through hole 3h. The metal bushing 3 has a plurality of protruding anti-rotation portions 31 formed on its outer circumferential surface at predetermined intervals in the circumferential direction. The anti-rotation portions 31 are embedded in the binding resin member 7. The anti-rotation portions 31 have the function of preventing the binding resin member 7 from rotating relative to the metal bushing 3 and preventing it from coming off.

[0021] The resin molded body 5 is a member that meshes with other gears. Figure 2 shows a front view and a cross-sectional view of the resin molded body 5 included in the composite structure gear 1 of Figure 1. As shown in Figures 1(a) and 1(b) and Figures 2(a) and 2(b), the resin molded body 5 is annular and coaxial with the metal bushing 3. The resin molded body 5 is provided around the metal bushing 3, and therefore around the binding resin member 7. The resin molded body 5 is configured to include an outer peripheral portion 51, an inner peripheral portion 52, and an intermediate portion 53.

[0022] The outer peripheral portion 51 is an annular portion provided on the outer periphery of the resin molded body 5. A tooth profile is formed on the outer peripheral portion 51. A plurality of tooth profiles are formed at predetermined intervals in the circumferential direction of the resin molded body 5. The inner peripheral portion 52 is an annular portion provided on the inner periphery of the resin molded body 5.

[0023] The intermediate portion 53 is a portion between the outer peripheral portion 51 and the inner peripheral portion 52. As shown in FIG. 2A , a plurality of recessed regions 531 are formed in the intermediate portion 53 of the resin molded body 5 at predetermined intervals in the circumferential direction. More specifically, in the intermediate portion 53 of the resin molded body 5, the recessed regions 531 and regions 532 are alternately arranged in the circumferential direction. Such a region 532 is a region sandwiched between two adjacent recessed regions 531.

[0024] As shown in FIG. 2B , each recessed region 531 has a thin-walled portion 531x with recesses 531y, 531y formed on both sides in the thickness direction of the resin molded body 5. In the recessed region 531, the sum of the depths D1, D1 of the recesses 531y, 531y on both sides is smaller than the thickness T1 of the thin-walled portion 531x. In other words, in the region 532 between the recessed regions 531, the sum of the heights of the inclined surfaces 532y, 532y (described below), which are convex portions on both sides, (i.e., D1 + D1) is smaller than the thickness T1 of the thin-walled portion 531x. Hereinafter, the depth D1 of the recess 531y may be referred to as the height D1 of the region 532 (specifically, the inclined surface 532y). Furthermore, the width W1 (see FIG. 5 ), which is the length in the circumferential direction of the region 532, is larger than the height D1 of the inclined surface 532y of the region 532, e.g., twice or more. The thickness T1 of the thin-walled portion 531x may be, for example, approximately 5 to 10 mm. The height D1 of the inclined surface 532y of the region 532 (the depth D1 of the recess 531y) may be, for example, approximately 2 to 5 mm. The width W1 (see FIG. 5) of the inclined surface 532y of the region 532 may be, for example, approximately 4 to 10 mm. Furthermore, the radial length R1 (see FIG. 2(a)) from the inner peripheral surface of the inner peripheral portion 52 to the outer peripheral surface of the outer peripheral portion 51 of the resin molded body 5 may be, for example, approximately 40 to 50% of the radius of the resin molded body 5, and specifically, approximately 15 to 20 mm.

[0025] 2A, the corners on the outer periphery of the recess 531y may be rounded to improve releasability from the mold. That is, the corners on the outer periphery of the recess 531y may be rounded.

[0026] Each region 532 is provided with a base portion 532x and a slope portion 532y. The base portion 532x is a portion provided at a position continuous with the outer circumferential portion 51. The slope portion 532y is a portion continuous with the base portion 532x and extending at an angle so that its thickness decreases radially toward the inner circumferential portion 52 (see FIG. 2B). The slope portion 532y is formed on both sides of the resin molded body 5 in the thickness direction.

[0027] The resin molded body 5 includes reinforcing fibers and a resin. The reinforcing fibers included in the resin molded body 5 are, for example, organic fibers. The reinforcing fibers may be, for example, aramid fibers, PBO (Poly-p-phenylenebenzobisoxazole) fibers, carbon fibers, glass fibers, or metal fibers. The resin included in the resin molded body 5 may be, for example, polyaminoamide resin, phenolic resin, or unsaturated polyester resin. The aramid fibers used as the reinforcing fibers may be para-aramid fibers, meta-aramid fibers, or para-aramid fiber pulp. When para-aramid fibers are used, their length may be 3 mm or more. When meta-aramid fibers are used, their length may be 3 mm or more, or 6 mm or more. The total fiber amount (volume) of the reinforcing fibers included in the resin molded body 5 may be 40% or more, or may be 40% or more and 60% or less.

[0028] The binding resin member 7 is a member that connects the resin molded body 5 and the metal bushing 3. The binding resin member 7 covers, for example, the surfaces of the intermediate portion 53 and the inner peripheral portion 52 of the resin molded body 5 and is provided up to a position where it contacts the outer peripheral surface of the metal bushing 3. The resin contained in the binding resin member 7 may be, for example, PPS (Polyphenylene sulfide), PEEK (Poly Ether Ether Ketone), PI (Polyimide), LCP (Liquid Crystal Polymer), PA (Polyamide), POM (Polyoxymethylene), PPE (Polyphenylene ether), or PBT (Poly Butylene Terephtalate), and may be reinforced with glass fiber. Note that the resin contained in the binding resin member 7 may be cheaper than the resin contained in the resin molded body 5.

[0029] Next, a description will be given of a manufacturing method of the composite structure gear 1. The manufacturing method of the composite structure gear 1 includes a step of forming a fiber assembly, a step of forming a resin rotor, a molding step, and a step of forming the resin molded body 5.

[0030] The step of forming a fibrous mass will now be described. In this step, short fibers are accumulated in an annular mold by a papermaking method, and compressed using a papermaking compression device (not shown) to form a fibrous mass surrounding the outer periphery of the metal bushing 3. The short fibers are mixed with water to form a slurry, which is then supplied to the mold of the papermaking compression device. Vacuum suction is then applied to remove the water, forming a circular fibrous mass.

[0031] Next, the step of forming the resin rotating body 556 will be described. In this step, the annular fiber assembly is clamped and compressed, impregnated with resin, and cured to form the resin rotating body 556. As shown in FIG. 3( a), a fiber substrate 555 is placed in a mold 101. The mold 101 includes a lower mold 109 and an upper mold 110 that are paired in the vertical direction and sandwich a metal bushing 3 or the like. As shown in FIG. 3( b), the lower mold 109 and the upper mold 110 are clamped together to forcibly compress the fiber substrate 555 into a shape that conforms to the contours of the lower mold 109 and the upper mold 110. Liquid resin is then injected into the mold 101 and cured, thereby forming the resin rotating body 556 containing reinforcing fibers and resin.

[0032] Next, the molding step will be described. In this step, a molded product is formed by connecting the resin rotor 556 and the metal bushing 3 with the binding resin member 7. Specifically, as shown in Fig. 4(a), the resin rotor 556 and the metal bushing 3 are set in separate molds, and after the molds are closed, the binding resin member 7 is injected to integrate them into a molded product, as shown in Fig. 4(b).

[0033] Finally, the step of forming the resin molded body 5 will be described. In this step, the outer periphery of the resin rotating body 556 is machined to form a tooth profile, thereby forming the resin molded body 5. In this manner, the composite structure gear 1 is manufactured in which the metal bushing 3 and the resin molded body 5 are connected by the binding resin member 7.

[0034] Next, the effects of the composite structure gear 1 (and the resin molded body 5) according to this embodiment will be described.

[0035] First, a composite structure gear 301 according to a comparative example will be described with reference to FIGS. 6 and 7 . As shown in FIG. 6 , the basic configuration of the composite structure gear 301 is similar to that of the composite structure gear 1 according to the present embodiment, and includes a resin molded body 305, a metal bushing 303, and a bonding resin member 307. The metal bushing 303 has a through hole 303h. The metal bushing 303 has a plurality of convex anti-rotation portions 331 formed at predetermined intervals in the circumferential direction on its outer circumferential surface. As shown in FIG. 7 , the recessed region 3531 of the resin molded body 305 has thin-walled portions 3531x formed with recesses 3531y, 3531y on both sides in the thickness direction of the resin molded body 305. In each recessed region 3531, the sum (D2 + D2) of the depths D2 of the recesses 3531y, 3531y on both sides is greater than the thickness T2 of the thin-walled portions 3531x. In the example shown in Figure 7, the depth D2 of the recess 3531y is approximately the same as the thickness T2 of the thin-walled portion 3531x, and the sum (D2 + D2) of the depths D2, D2 of the recesses 3531y, 3531y on both sides is approximately twice the thickness T2 of the thin-walled portion 3531x.

[0036] In a resin molded body 305 in which the depth D2 of the recess 3531y is deep, the reinforcing fibers cannot be properly adhered to the region adjacent to the recess 3531y (e.g., the protrusion) during molding, which may result in a weakened strength. Figure 8 is a diagram showing the state of the fiber substrate 555 (reinforcing fibers) during mold clamping compression for the resin molded body 305. As shown in Figure 8, if the depth of the recess 3531y after molding is deep, the fiber substrate 555 (reinforcing fibers) does not properly conform to the upper mold 110, and the reinforcing fibers cannot be properly provided in the region adjacent to the recess 3531y.

[0037] In contrast, the composite structure gear 1 according to this embodiment includes an annular resin molded body 5 containing reinforcing fibers and resin and having teeth formed on an outer periphery 51, an annular metal bushing 3, and a binder resin member 7 connecting the resin molded body 5 and the metal bushing 3. The resin molded body 5 has a plurality of recessed regions 531 formed at predetermined intervals in the circumferential direction, with regions 532 formed between adjacent recessed regions 531, and the recessed regions 531 have thin-walled portions 531x with recesses 531y formed on both sides in the thickness direction of the resin molded body 5. As shown in FIG. 2(b), in the recessed region 531, the sum of the depths D1 of the recesses 531y on both sides is smaller than the thickness T1 of the thin-walled portions 531x.

[0038] In this composite structure gear 1, a plurality of recessed regions 531 are formed in the circumferential direction of the annular resin molded body 5, and each recessed region 531 has a thin-walled portion 531x with recesses 531y, 531y formed on both sides in the thickness direction of the resin molded body 5. In each recessed region 531, the sum of the depths D1, D1 of the recesses 531y, 531y on both sides is smaller than the thickness T1 of the thin-walled portion 531x. By forming the recesses shallow in this way, reinforcing fibers can be provided so as to appropriately follow the regions 532 between adjacent recessed regions 531 during molding of the resin molded body 5. That is, if the recess 3531y is formed deep, as in the configuration of the comparative example, it is difficult to have the reinforcing fibers extend to the region 532 between the recessed regions 531. However, by making the recess 531y shallow enough that the sum of the depths of the recesses 531y, 531y on both sides is smaller than the thickness of the thin-walled portion 531x, the reinforcing fibers can be appropriately provided in the region 532 adjacent to the recessed region 531. This allows for a balanced provision of reinforcing fibers even in a resin molded body 5 having continuous uneven portions. Note that a shallow recess can cause a problem of reduced bonding strength between the resin molded body 5 and the bonding resin member 7. However, as described above, since the reinforcing fibers are appropriately provided in the region 532, the strength can be ensured by the reinforcing fibers, and the reduction in bonding strength can be appropriately suppressed. As described above, the configuration of this embodiment can provide a composite structure gear 1 with improved strength through a balanced provision of reinforcing fibers.

[0039] The reinforcing fibers may be organic fibers or aramid fibers, etc. This configuration can adequately ensure the strength of the composite structure gear 1.

[0040] 5, the width W1 of the region 532, which is the length in the circumferential direction, may be greater than the height D1, for example, two times or more. By making the width wide and the depth shallow in this way, the reinforcing fibers can be made to properly follow the region 532 during clamping compression.

[0041] The length R1 in the radial direction from the inner peripheral surface of the inner peripheral portion 52 to the outer peripheral surface of the outer peripheral portion 51 of the resin molded body 5 may be 40 to 50% or 30 to 40% of the radius of the resin molded body 5. This makes it possible to adjust the amount of the resin molded body 5 while ensuring appropriate strength and also to suppress cost increases.

[0042] The outer corners of the recess 531y may be rounded (may have a rounded shape). This configuration can improve the releasability from the mold.

[0043] The total amount (volume) of the reinforcing fibers contained in the resin molded body 5 may be 40% or more. With this configuration, it is possible to impart appropriate strength to the resin molded body 5.

[0044] Although one embodiment of the present invention has been described above, the present invention is not limited to the above. For example, the composite structure gear 1A shown in Figures 9 and 10 may be used as the composite structure gear. As shown in Figure 9, the basic configuration of the composite structure gear 1A is the same as that of the composite structure gear 1 according to the above-described embodiment, and includes a resin molded body 5A, a metal bushing 3, and a bonding resin member 7. Here, the resin molded body 5A of the composite structure gear 1A, which is a difference in configuration from the composite structure gear 1, will be described in detail.

[0045] 10A and 10B are a front view (FIG. 10A) and a cross-sectional view (FIG. 10B) of the resin molded body 5A included in the composite structure gear 1A of FIG. 9. As shown in FIG. 10, a plurality of recessed regions 531A are formed at predetermined intervals in the circumferential direction in the central portion 53A of the resin molded body 5A, and the recessed regions 531A are provided with thin-walled portions 531Ax in which recesses 531Ay, 531Ay are formed on both sides in the thickness direction of the resin molded body 5A. As shown in FIG. 10B, in the recessed region 531A, the sum of the depths of the recesses 531Ay, 531Ay on both sides is smaller than the thickness of the thin-walled portions 531Ax.

[0046] 10(a) and 2(a), the radial length R2 from the inner peripheral surface of inner peripheral portion 52A to the outer peripheral surface of outer peripheral portion 51A in resin molded body 5A (see FIG. 10(a)) is smaller than the radial length R1 from the inner peripheral surface of inner peripheral portion 52 to the outer peripheral surface of outer peripheral portion 51 in resin molded body 5A (see FIG. 2(a)). Specifically, the radial length R2 from the inner peripheral surface of inner peripheral portion 52A to the outer peripheral surface of outer peripheral portion 51A in resin molded body 5A may be about 30 to 40% of the radius of resin molded body 5A, and this value may be about 10 to 15 mm.

[0047] By reducing the radial length R2 of the resin molding 5A in this manner, the volume of the resin molding 5A, which is more expensive than the binding resin member 7, can be reduced, and material costs can be reduced.

[0048] 1, 1A... composite structure gear, 3... metal bushing, 5, 5A... resin molded body, 7... bonding resin member, 531, 531A... recessed area, 531x, 531Ax... thin-walled portion, 531y, 531Ay... recess, D1... depth of recess (height of area between recessed areas), W1... width (length in the circumferential direction).

Claims

1. A composite structure rotating body comprising: an annular resin molding containing reinforcing fibers and resin, and having a tooth pattern formed on its outer periphery; an annular metallic bushing; and a bonding resin member connecting the resin molding and the metallic bushing, wherein the resin molding has a plurality of recessed regions formed at predetermined intervals in the circumferential direction, and each recessed region has a thin-walled portion with recesses formed on both sides in the thickness direction of the resin molding, and the sum of the depths of the recesses on both sides in the recessed region is smaller than the thickness of the thin-walled portion.

2. The composite structure rotating body according to claim 1, wherein the reinforcing fibers are organic fibers.

3. The composite structure rotating body according to claim 1, wherein said reinforcing fibers are aramid fibers.

4. A composite structure rotating body according to any one of claims 1 to 3, wherein the length in the circumferential direction of the area sandwiched between two adjacent recessed areas is greater than its height.

5. A composite structure rotating body according to claim 4, wherein the length in the circumferential direction of the area sandwiched between two adjacent recessed areas is at least twice its height.

6. A composite structure rotating body as claimed in any one of claims 1 to 5, wherein the radial length from the inner surface of the inner circumference portion to the outer surface of the outer circumference portion of the resin molding is 40 to 50% or 30 to 40% of the radius of the resin molding.

7. A composite structure rotating body according to any one of claims 1 to 6, wherein the outer peripheral corners of the recess are rounded.

8. A composite structure rotating body according to any one of claims 1 to 7, wherein the total amount (volume) of the reinforcing fibers contained in the resin molding is 40% or more.

9. A ring-shaped resin molding that is connected to a metal bush by a bonding resin member to form a composite structure rotating body, the resin molding comprising reinforcing fibers and resin, a plurality of recessed regions formed at predetermined intervals in the circumferential direction, each of the recessed regions having a thin-walled portion with recesses formed on both sides in the thickness direction, and the sum of the depths of the recesses on both sides of each of the recessed regions is smaller than the thickness of the thin-walled portion.

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