Knuckle Castings

Abstract

To provide a technology which achieves improvement of castability despite a knuckle cast including a first reinforcement rib and a second reinforcement rib designed to improve rigidity.SOLUTION: A knuckle cast 20 comprises a casting plan part 22 and a product part 23 formed along flow of a molten metal 21. The product part 23 includes: an intermediate part 26; a first fastening part 27 integrally formed with one end (the casting plan part 22 side) of the intermediate part 26; a second fastening part 28 integrally formed with the other end of the intermediate part 26; and a first rib 31 and a second rib 32 which are integrally formed with the intermediate part 26 so as to extend from the first fastening part 27 to the second fastening part 28. The first rib 31 and the second rib 32 are not parallel to each other and are arranged in a V shape so that a rib interval W1 at the first fastening part 27 side becomes narrower than a rib interval W2 at the second fastening part 28 side.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a knuckle casting and a knuckle. In the present invention, a knuckle as a product (product knuckle) is simply called a "knuckle" to distinguish it from a knuckle casting. [Background technology]

[0002] 2. Description of the Related Art Vehicles such as passenger cars are provided with components called knuckles that hold wheels. Among such knuckles, those equipped with reinforcing ribs are known (see, for example, Patent Document 1 (FIG. 2)).

[0003] Patent Document 1 will be explained with reference to the following figure. FIG. 9 is a front view and a right side view of a conventional knuckle. As shown in FIG. 9(a), the knuckle 100 has as its basic elements an intermediate portion 101, a first connecting portion 102 formed at one end of the intermediate portion 101, and a second connecting portion 103 formed at the other end of the intermediate portion 101. Fastened members such as a lower arm, an upper arm, a brake carrier, and a link member are fastened to the first connecting portion 102 and the second connecting portion 103 by bolts (Patent Document 1, paragraph 0013).

[0004] As shown in FIG. 9(b), the knuckle 100 is provided with a first rib 104 and a second rib 105. As shown in Figure 9(a), when the line passing through the center of the first connection portion 102 and the center of the second connection portion 103 is taken as the center line 106, the first rib 104 and the second rib 105 are arranged so as to be parallel to the center line 106.

[0005] A knuckle 200 having a different configuration from that of Patent Document 1 will be described with reference to FIG. As shown in FIG. 10 , a conventional knuckle 200 includes a product intermediate portion 201, an axle fastening portion 202 formed integrally with one end of the product intermediate portion 201, a damper fastening portion 203 formed integrally with the other end of the product intermediate portion 201, a rod fastening portion 204 formed and protruding from the axle fastening portion 202 to the right in the figure, a brake fastening portion 205 formed and protruding from the axle fastening portion 202 to the left in the figure, and a lower arm fastening portion 206 formed and protruding from the axle fastening portion 202 downward in the figure.

[0006] An axle is fastened to the axle fastening portion 202 . A damper is fastened to the damper fastening portion 203 . A steering tie rod is fastened to the rod fastening portion 204 . A brake carrier (brake caliper) is fastened to the brake fastening portion 205. The lower arm is fastened to the lower arm fastening portion 206 .

[0007] The present inventors have tried to provide the knuckle 200 with ribs (a pair of parallel reinforcing ribs) similar to those in Patent Document 1. That is, a first reinforcing rib 207 and a second reinforcing rib 208 extending from the axle fastening portion 202 to the damper fastening portion 203 are integrally formed on the product intermediate portion 201 .

[0008] The first reinforcing rib 207 and the second reinforcing rib 208 improve rigidity. On the other hand, it was found that castability (molten metal running and solidification directionality) was sacrificed due to the provision of the first reinforcing rib 207 and the second reinforcing rib 208. The reason for this will be explained in detail in the "Comparative Example" below. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2017-74863 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a technique that can improve castability even when a knuckle casting is provided with first and second reinforcing ribs for the purpose of improving rigidity. [Means for solving the problem]

[0011] The invention of claim 1 is a knuckle casting from which a knuckle product is obtained by machining, This knuckle casting is a casting that comprises a design portion and a product portion that are formed along the flow of molten metal, and is designed so that the design portion solidifies after the product portion solidifies, and after solidification, the design portion is separated from the product portion, and the design portion is sent to a remelting process, and the product portion is subjected to the machining. The product portion includes an intermediate portion, a first fastening portion integrally formed at one end of the intermediate portion and formed on the side of the design portion, a second fastening portion integrally formed at the other end of the intermediate portion, and a first rib and a second rib integrally formed on the intermediate portion so as to extend from the first fastening portion to the second fastening portion, The first rib and the second rib are non-parallel and arranged in a V-shape such that the rib spacing on the first fastening portion side is narrower than the rib spacing on the second fastening portion side. And, The plan section includes a final solidification section that solidifies the slowest, The intersection of the longitudinal axis of the first rib and the longitudinal axis of the second rib overlaps the final solidified portion. It is characterized by:

[0013] Claim 2 The invention according to claim Article 1 The knuckle casting described above, the first fastening portion is a portion to which an axle is fastened, The second fastening portion is a portion to which a damper is fastened. [Effects of the Invention]

[0015] In the invention according to claim 1, the first rib and the second rib are arranged in a V-shape so that the first rib and the second rib are oriented toward the plan portion. In the casting process, after the filling of the molten metal is completed, heat is removed by the mold and the molten metal begins to solidify. At this time, the unsolidified molten metal passes through the first rib and the second rib toward the plan portion. According to the present invention, the first rib and the second rib are oriented toward the plan portion, so the unsolidified molten metal smoothly flows toward the plan portion. As a result, solidification directionality is significantly improved. Improved solidification directionality improves castability. That is, according to the present invention, a technique is provided that can improve castability even when the knuckle casting is provided with first and second ribs for the purpose of improving rigidity.

[0016] In addition, Claim 1 In the invention according to claim 1, the intersection of the longitudinal axis of the first rib and the longitudinal axis of the second rib overlaps with the final solidified portion in the plan portion. Since the unsolidified molten metal is directed directly to the final solidified portion, the solidification directionality is further improved.

[0017] Claim 2 In the invention according to the present invention, the first rib and the second rib are provided between the portion where the axle is fastened and the portion where the damper is fastened. External forces exert a large bending force between the area where the axle is fastened and the area where the damper is fastened. Providing the first and second ribs in these areas sufficiently increases rigidity. In other words, sufficient rigidity can be imparted without increasing the thickness of the middle section. As a result, the knuckle can be easily made thinner and lighter. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. [Figure 2] FIG. 2 is a view taken along arrow 2 in FIG. 1 (a front view of the knuckle). [Figure 3] FIG. 3 is a view taken along arrow 3 in FIG. 1 (right side view of the knuckle). [Figure 4] FIG. 1 is a plan view of a knuckle casting according to the present invention. [Figure 5] FIG. 10 is a plan view of a comparative example. [Figure 6] FIG. 10 is a diagram illustrating the solidification time of a first reinforcing rib. [Figure 7] FIG. 10 is a diagram illustrating the solidification time of a second reinforcing rib. [Figure 8] FIG. 10 is a diagram illustrating a more preferred embodiment. [Figure 9] 1A and 1B are a front view and a right side view of a conventional knuckle; [Figure 10] FIG. 1 is a perspective view of another conventional knuckle. DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of the present invention will be described below with reference to the accompanying drawings. [Example]

[0021] 1 to 3 show a knuckle 10 as a product. The knuckle 10 is obtained by subjecting a knuckle casting to machining or the like.

[0022] As shown in FIG. 1, the knuckle 10 includes a product intermediate portion 11, an axle fastening portion 12 formed integrally with one end of the product intermediate portion 11, a damper fastening portion 13 formed integrally with the other end of the product intermediate portion 11, a rod fastening portion 14 formed by protruding from the axle fastening portion 12 to the right in the figure, and a brake fastening portion 15 formed by protruding from the axle fastening portion 12 to the left in the figure.

[0023] An axle is fastened to the axle fastening portion 12. The damper fastening portion 13 has a machined hole 19 into which the damper is fastened. A steering tie rod is fastened to the rod fastening portion 14. A brake caliper is fastened to the brake fastening portion 15.

[0024] A first reinforcing rib 16 and a second reinforcing rib 17 are integrally formed in the product intermediate portion 11 so as to extend from the axle fastening portion 12 to the damper fastening portion 13. The first reinforcing rib 16 and the second reinforcing rib 17 are arranged non-parallel to each other and are arranged in a V-shape so that the rib spacing on the axle fastening portion side 12 is narrower than the rib spacing on the damper fastening portion side 13.

[0025] As shown in Fig. 2, the knuckle 10 is integrally provided at its lower part with an arm fastening portion 18. A lower arm is fastened to this arm fastening portion 18. For other parts, the same reference numerals as in Fig. 1 are used, and detailed description thereof will be omitted.

[0026] As shown in Fig. 3, a first reinforcing rib 16 and a second reinforcing rib 17 are integrally formed in the product intermediate portion 11 so as to extend from the axle fastening portion 12 to the damper fastening portion 13. For the rest, the reference numerals in Fig. 1 are used and detailed description will be omitted.

[0027] The knuckle casting that is the basis for the knuckle 10 described above will be described below. As shown in Fig. 4, a knuckle casting 20 comprises a plan portion 22 and a product portion 23 formed along the flow of molten metal 21. The plan portion 22 solidifies after the product portion 23 solidifies. The area near the center of the plan portion 22 becomes the final solidified portion 29.

[0028] Once solidification is complete, the plan portion 22 is separated from the product portion 23 along a separation line 24. The plan portion 22 is sent to a remelting process and machined into a product portion 23, thereby obtaining the knuckle 10 described with reference to FIGS.

[0029] The product section 23 comprises an intermediate section 26, a first fastening section 27 integrally formed at one end (the side of the plan section 22) of the intermediate section 26, a second fastening section 28 integrally formed at the other end of the intermediate section 26, and a first rib 31 and a second rib 32 integrally formed with the intermediate section 26 and extending from the first fastening section 27 to the second fastening section 28.

[0030] The knuckle 10 shown in FIG. 2 is obtained by machining the product portion 23, so that the first fastening portion 27 corresponds to the portion for fastening the axle (axle fastening portion 12 in FIG. 1), and the second fastening portion 28 corresponds to the portion for fastening the damper (damper fastening portion 13 in FIG. 1).

[0031] The product portion 23 further extends from the intermediate portion 26 to the right in the figure. overhang The protruding portion 33 is integrally provided. death A rod fastening portion (FIG. 1, reference numeral 14) will be formed in the portion 33 in a later process.

[0032] The first rib 31 and the second rib 32 are non-parallel to a center line 34 passing through the center of the first fastening portion 27 and the center of the second fastening portion 28, and are arranged in a V shape so that the rib spacing W1 on the first fastening portion 27 side is narrower than the rib spacing W2 on the second fastening portion 28 side.

[0033] In the embodiment, both the first rib 31 and the second rib 32 are non-parallel to the center line 34, but only one of the ribs may be non-parallel to the center line 34 and the other may be parallel (including approximately parallel) to the center line 34. The key is to form a V-shape.

[0034] In order to examine the advantages of the first rib 31 and second rib 32 of the present invention, which are arranged in a V-shape, a knuckle casting in which a pair of ribs are arranged in parallel will be used as a "comparative example." As shown in FIG. 5, a knuckle casting 120 in the comparative example is composed of a plan portion 122 and a product portion 123. The product portion 123 includes an intermediate portion 126, a first fastening portion 127, a second fastening portion 128, a first rib 131 and a second rib 132 that are integrally formed with the intermediate portion 126 and extend from the first fastening portion 127 to the second fastening portion 128, and a protruding portion. death It has a section 133.

[0035] The first rib 131 and the second rib 132 are parallel to a center line 134 that passes through the center of the first fastening portion 127 and the center of the second fastening portion 128 .

[0036] The knuckle casting 20 (embodiment) and the knuckle casting 120 (comparison example) described above will be compared. This comparison will be explained based on FIGS.

[0037] FIG. 6 is a diagram illustrating the solidification state of the first reinforcing rib. FIG. 6(a) shows a knuckle casting 120 (comparative example), and FIG. 6(b) is a diagram illustrating the solidification time in the cross section taken along line bb in FIG. 6(a). In Figure 6(b), the clotting time t1 in the shaded area is 10 to 18 seconds, and the clotting time t2 in the dotted area is 18 to 22 seconds. That is, coagulation progresses (directs) from the left and right surface layers toward the center in the intermediate portion including the first rib 131. The distance between the left coagulation time t2 area and the right coagulation time t2 area is defined as D1.

[0038] FIG. 6(c) shows a knuckle casting 20 (Example), and FIG. 6(d) is a diagram for explaining the solidification time in the cross section taken along line dd in FIG. 6(c). In Figure 6(d), the clotting time t1 in the shaded area is 10 to 18 seconds, and the clotting time t2 in the dotted area is 18 to 22 seconds. That is, solidification progresses (is directed) from the left and right surface layers toward the center in the intermediate portion including the first rib 31. The distance between the left solidification time t2 area and the right solidification time t2 area is defined as D2.

[0039] Distance D2 is significantly smaller than distance D1. In addition, in Figure 6(d), the tip of the coagulation time t2 area is "U" shaped, and the boundary of the coagulation tendency is clear. In contrast, in Figure 6(b), the boundary of the coagulation tendency is not clear.

[0040] 6(d), since the boundary between solidification trends is clear, the unsolidified molten metal is pushed out to the first fastening portion 27 and the second fastening portion 28. As a result, casting defects such as voids are less likely to remain in the first rib 31. In contrast, in Figure 6(b), the boundary between solidification trends is not clear, so casting defects such as voids are more likely to remain.

[0041] The above trends are also verified in Figure 4. In Figure 4, after the filling of the molten metal 21 is completed in the casting process, the heat is removed (cooled) by the mold, and the molten metal 21 begins to solidify. The solidification of the molten metal 21 may be uneven depending on the shape of the product and the shape of the mold. In general, shrinkage cavities are likely to occur in the final part of solidification due to solidification shrinkage of the metal.

[0042] As illustrated in FIG. 6(d), the unsolidified molten metal flows toward the first fastening portion 27 and the second fastening portion . In Fig. 4, the molten metal flowing toward the first fastened portion 27 flows toward the final solidification portion 29, and the molten metal flowing toward the second fastened portion 28 flows toward the center of the second fastened portion 28. The center of the second fastened portion 28 becomes the delayed solidification portion 30 on the product side.

[0043] Shrinkage cavities tend to occur in the final solidification portion 29 and the delayed solidification portion 30 on the product side. Because solidification directionality is clear, the areas where shrinkage cavities occur are limited to the final solidification portion 29 and the delayed solidification portion 30 on the product side. The final solidification portion 29 is included in the plan portion 22 separated by the separation line 24, and therefore does not affect the product portion 23. Furthermore, the delayed solidification portion 30 on the product side is cut and removed when machining the machined hole (FIG. 1, reference numeral 19).

[0044] That is, solidification begins from the intermediate portion 26. As a result, by controlling the solidification directionality, casting defects such as shrinkage cavities do not occur in the product portion 23 including the intermediate portion 26, which results in improved internal quality, ensured strength, improved productivity, and improved castability. In contrast, in the comparative example described in FIGS. 6(a) and 6(b), the boundary between the solidification tendencies is not clear, and therefore, compared to the example described in FIGS. 6(c) and 6(d), there remains a risk that shrinkage cavities may occur in the product.

[0045] FIG. 7 is a diagram illustrating the solidification state of the second reinforcing rib. FIG. 7(a) shows a knuckle casting 120 (comparative example), and FIG. 7(b) is a diagram illustrating the solidification time in the cross section taken along line bb in FIG. 7(a). In Figure 7(b), the clotting time t1 in the shaded area is 10 to 16 seconds. The clotting time t3 in the dotted area is 16 to 18 seconds. The distance between the left clotting time t3 area and the right clotting time t3 area is D3. The second rib 132 is a protruding portion having a large heat capacity. death Since the second rib is affected by the portion 133, it is more difficult to solidify than the first rib.

[0046] FIG. 7(c) shows a knuckle casting 20 (Example), and FIG. 7(d) is a diagram for explaining the solidification time in the cross section taken along line dd in FIG. 7(c). In Figure 7(d), the clotting time t1 in the shaded area is 10 to 16 seconds, and the clotting time t3 in the dotted area is 16 to 18 seconds. The distance between the left clotting time t3 area and the right clotting time t3 area is defined as D4. The second rib 32 is a protruding portion having a large heat capacity. death Since the second rib is affected by the portion 33, it is more difficult to solidify than the first rib.

[0047] Distance D4 is significantly smaller than distance D3. In addition, in Figure 7(d), the tip of the coagulation time t3 area is "L" shaped, and the boundary of the coagulation tendency is clear. In contrast, in Figure 7(b), the boundary of the coagulation tendency is not clear.

[0048] 7(d), since the boundary between solidification trends is clear, the unsolidified molten metal is pushed out to the first fastening portion 27 and the second fastening portion 28. As a result, casting defects such as voids are less likely to remain in the first rib 31. In contrast, in Figure 7(b), the boundary between solidification trends is not clear, so casting defects such as voids are more likely to remain.

[0049] 7(c) and (d), solidification begins from the middle part. As a result, by controlling the solidification direction, casting defects such as shrinkage cavities do not occur in the product part, including the middle part, which results in improved internal quality, ensured strength, and improved productivity. In contrast, in the comparative example described in FIGS. 7(a) and 7(b), the boundary between the solidification tendencies is not clear, and therefore, compared to the example described in FIGS. 7(c) and 7(d), there remains a risk that shrinkage cavities may occur in the product.

[0050] 6 and 7, a significant difference was observed in terms of solidification directionality between the comparative example and the example. The reason for this difference will be presumed. In FIG. 5 (comparison example), the first rib 131 and the second rib 132 are parallel to each other, so that the longitudinal axis 131B of the first rib 131 is parallel to the longitudinal axis 131B of the plan portion 12. 2 Similarly, the longitudinal axis 132B of the second rib 132 is not oriented toward the final solidified portion 129 in the 2 It is not directed towards the final solidified portion 129 inside. A portion of the unsolidified molten metal flows along the longitudinal axes 131B and 132B to the plan section 12. 2 , but not to the final solidification portion 129. Therefore, as shown in FIG. 6(b) and FIG. 7(b), the boundary between the solidification directions is not clear.

[0051] In contrast, in Figure 4 (embodiment), the first rib 31 and the second rib 32 are arranged in a V shape, with the longitudinal axis 31B of the first rib 31 pointing toward the final solidified portion 29 and the longitudinal axis 32B of the second rib 32 pointing toward the final solidified portion 29. A part of the unsolidified molten metal flows along the longitudinal axes 31B and 32B toward the final solidification portion 29. Therefore, as shown in Figure 6(d) and Figure 7(d), the boundary between the solidification directions becomes clear.

[0052] Next, the preferable sizes of the rib intervals W1 and W2 shown in FIG. 4 were investigated. Models 1 to 4 were created by setting the rib spacing W1 to a ratio of 1.0 and the rib spacing W2 to a ratio in the range of 1.15 to 1.45, and the castability was examined for Models 1 to 4. The results are shown in Table 1.

[0053] [Table 1]

[0054] In Model 1, W2 was set to 1.15. Because the difference between W1 and W2 was small, the effect of the V shape was not exerted and the improvement in castability was small. The result was ×. In Model 2, W2 was set to 1.28. The V-shape was effective and good castability was obtained. The result was good. In Model 3, W2 was set to 1.33. The V-shape was effective enough to obtain good castability. The result was good. In Model 4, W2 was set to 1.45. The V-shaped angle became larger, which affected the flow of the molten metal. The result was △.

[0055] As a result, when the rib spacing W1 is set to a ratio of "1.0", it is recommended that the rib spacing W2 be set to a ratio in the range of 1.28 to 1.33.

[0056] Next, a more preferred embodiment will be described. 8, the plan section 22 is configured to include the final solidification portion 29, and the intersection of the longitudinal axis 31B of the first rib 31 and the longitudinal axis 32B of the second rib 32 is configured to overlap the final solidification portion 29. The intersection does not have to be at the center of the final solidification portion 29; it can be at the edge as long as it is within the final solidification portion 29.

[0057] Since the unsolidified molten metal flows toward the final solidified portion 29 along the longitudinal axes 31B and 32B, the solidification directionality becomes clearer, and the occurrence of casting defects can be more reliably avoided.

[0058] Although in the embodiment an axle is fastened to the first fastening portion 27, other arms or rods may also be fastened to the first fastening portion 27. Similarly, although a damper is fastened to the second fastening portion 28, other arms or rods may also be fastened to the second fastening portion 28. [Industrial Applicability]

[0059] The present invention is suitable for use in a knuckle that holds a wheel. [Explanation of symbols]

[0060] 10...knuckle, 12...axle fastening portion, 13...damper fastening portion, 16...first reinforcing rib, 17...second reinforcing rib, 20...knuckle casting, 21...molten metal, 22...plan portion, 23...product portion, 24...separation line, 26...middle portion, 27...first fastening portion, 28...second fastening portion, 29...final solidification portion, 31...first rib, 31B...longitudinal axis of first rib, 32...second rib, 32B...longitudinal axis of second rib, 34...center line, W1...rib spacing on the first fastening portion side, W2...rib spacing on the second fastening portion side.

Claims

1. A knuckle casting that can be machined to produce a knuckle as a product, This knuckle casting is a casting that comprises a design portion and a product portion that are formed along the flow of molten metal, and is designed so that the design portion solidifies after the product portion solidifies, and after solidification, the design portion is separated from the product portion, and the design portion is sent to a remelting process, and the product portion is subjected to the machining. The product portion includes an intermediate portion, a first fastening portion integrally formed at one end of the intermediate portion and formed on the design portion side, a second fastening portion integrally formed at the other end of the intermediate portion, and a first rib and a second rib integrally formed on the intermediate portion so as to extend from the first fastening portion to the second fastening portion, the first rib and the second rib are non-parallel and arranged in a V-shape such that a rib spacing on the first fastening portion side is narrower than a rib spacing on the second fastening portion side, The plan section includes a final solidification section that solidifies the slowest, A knuckle casting, characterized in that an intersection of a longitudinal axis of the first rib and a longitudinal axis of the second rib overlaps the final solidified portion.

2. 2. The knuckle casting according to claim 1, the first fastening portion is a portion to which an axle is fastened, The knuckle casting is characterized in that the second fastening portion is a portion to which a damper is fastened.

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