Knuckle cast and knuckle

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, the knuckle as a product (product knuckle) is simply referred to as "knuckle" and is distinguished from the knuckle casting.

Background Art

[0002] A member called a knuckle for holding a wheel is attached to a vehicle such as a passenger car. Among such knuckles, those provided with reinforcing ribs are known (see, for example, Patent Document 1 (FIG. 2)).

[0003] Patent Document 1 will be described based on 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 a middle portion 101, a first connection portion 102 formed at one end of the middle portion 101, and a second connection portion 103 formed at the other end of the middle portion 101 as basic elements. Fastening members such as a lower arm, an upper arm, a brake carrier, and a link member are fastened to the first connection portion 102 and the second connection portion 103 with 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 FIG. 9(a), when a line passing through the center of the first connection portion 102 and the center of the second connection portion 103 is defined as a center line 106, the first rib 104 and the second rib 105 are provided so as to be parallel to the center line 106.

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

[0006] The axle is fastened to the axle fastening section 202. A damper is fastened to the damper fastening section 203. A tie rod for steering is fastened to the rod fastening section 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 inventors attached ribs (a pair of parallel reinforcing ribs) similar to those in Patent Document 1 to the knuckle 200. In other words, the first reinforcing rib 207 and the second reinforcing rib 208, which extend from the axle fastening portion 202 to the damper fastening portion 203, are integrally formed in the intermediate portion 201 of the product.

[0008] The first reinforcing rib 207 and the second reinforcing rib 208 improve rigidity. On the other hand, it was found that the castability (molten metal flow and solidification directionality) was compromised due to the inclusion 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 Publication No. 2017-74863 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention aims to provide a technology that improves castability even when a knuckle casting is equipped with a first reinforcing rib and a second reinforcing rib for the purpose of improving rigidity. [Means for solving the problem]

[0011] The invention according to claim 1 is a knuckle casting that can be obtained as a product by machining, This knuckle casting consists of a plan section and a product section formed along the flow of molten metal, and is designed so that the plan section solidifies after the product section solidifies. After solidification, the plan section is separated from the product section, the plan section is sent to a remelting process, and the product section is subjected to the machining process. The product portion comprises an intermediate portion, a first fastening portion integrally formed at one end of the intermediate portion and formed on the side of the bracket 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 at 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 are arranged in a V-shape such that the spacing between the ribs on the first fastening portion side is narrower than the spacing between the ribs on the second fastening portion side.

[0012] The invention according to claim 2 is a knuckle casting according to claim 1, The aforementioned plan section includes the final solidification section which solidifies most slowly. The intersection of the longitudinal axis of the first rib and the longitudinal axis of the second rib is characterized in that it overlaps with the final solidified portion.

[0013] The invention according to claim 3 is a knuckle casting according to claim 1 or claim 2, The first fastening part is the part to which the axle is fastened, The second fastening portion is characterized by being the part to which the damper is fastened.

[0014] The invention according to claim 4 is a knuckle comprising a product intermediate part, a axle fastening part integrally formed at one end of the product intermediate part to which an axle is fastened, and a damper fastening part integrally formed at the other end of the product intermediate part to which a damper is fastened. This knuckle includes a first reinforcing rib and a second reinforcing rib that are integrally formed with the product intermediate part so as to extend from the axle fastening part to the damper fastening part. The first reinforcing rib and the second reinforcing rib are non-parallel and are arranged in a V shape such that the rib interval on the axle fastening part side is narrower than the rib interval on the damper fastening part side.

Advantages of the Invention

[0015] In the invention according to claim 1, the first rib and the second rib are arranged in a V shape such that the first rib and the second rib point to the solution part. After the filling of the molten metal is completed in the casting process, heat is extracted by the mold and the solidification of the molten metal begins. At this time, the unfrozen molten metal passes through the first rib and the second rib and heads towards the solution part. According to the present invention, since the first rib and the second rib point to the solution part, the unfrozen molten metal smoothly heads towards the solution part. As a result, the solidification orientation is significantly improved. Since the solidification orientation is improved, the casting property is improved. That is, according to the present invention, there is provided a technique capable of improving the casting property even though the knuckle casting includes the first rib and the second rib for the purpose of improving rigidity.

[0016] In the invention according to claim 2, the intersection of the longitudinal axis of the first rib and the longitudinal axis of the second rib overlaps with the final solidification part in the solution part. Since the unfrozen molten metal directly heads towards the final solidification part, the solidification orientation is further improved.

[0017] In the invention according to claim 3, the first rib and the second rib are extended to the part where the axle is fastened and the part where the damper is fastened. A large bending force is applied by an external force between the part to which the axle is fastened and the part to which the damper is fastened. The first rib and the second rib are provided at such a part to sufficiently increase the rigidity. That is, sufficient rigidity can be imparted without increasing the wall thickness of the middle part. As a result, thinning and weight reduction of the knuckle can be easily achieved.

[0018] In the invention according to claim 4, the first reinforcing rib and the second reinforcing rib are arranged in a V shape on the knuckle. Similar to claim 1, since the first reinforcing rib and the second reinforcing rib are directed toward the gating part, the unfrozen molten metal smoothly flows toward the gating part. As a result, the solidification orientation is significantly improved. Since the solidification orientation is improved, the casting property is improved. That is, according to the present invention, there is provided a technique capable of improving the casting property even though the knuckle casting is provided with the first reinforcing rib and the second reinforcing rib for the purpose of improving the rigidity.

Brief Description of the Drawings

[0019] [Figure 1] It is a plan view of the knuckle. [Figure 2] It is a view taken in the direction of arrow 2 in FIG. 1 (front view of the knuckle). [Figure 3] It is a view taken in the direction of arrow 3 in FIG. 1 (right side view of the knuckle). [Figure 4] It is a plan view of the knuckle casting according to the present invention. [[ID=D26]] [Figure 5] It is a plan view of the comparative example. [Figure 6] It is a diagram for explaining the solidification time of the first reinforcing rib. [Figure 7] It is a diagram for explaining the solidification time of the second reinforcing rib. [Figure 8] It is a diagram for explaining a more preferable embodiment. [Figure 9] It is a front view and a right side view of a conventional knuckle. [Figure 10] It is a perspective view of another conventional knuckle.

Modes for Carrying Out the Invention

[0020] Embodiments of the present invention will be described below with reference to the attached drawings. [Examples]

[0021] Figures 1 to 3 show the knuckle 10 as a product. This knuckle 10 is obtained by machining a knuckle casting.

[0022] As shown in Figure 1, the knuckle 10 comprises a product intermediate portion 11, an axle fastening portion 12 integrally formed at one end of the product intermediate portion 11, a damper fastening portion 13 integrally formed at the other end of the product intermediate portion 11, a rod fastening portion 14 extending to the right from the axle fastening portion 12, and a brake fastening portion 15 extending to the left from the axle fastening portion 12.

[0023] The axle is fastened to the axle fastening section 12. A machined hole 19 is provided in the damper fastening portion 13, and the damper is fastened to this machined hole 19. A tie rod for steering is fastened to the rod fastening section 14. A brake caliper is fastened to the brake fastening portion 15.

[0024] Furthermore, a first reinforcing rib 16 and a second reinforcing rib 17 are integrally formed in the intermediate portion 11 of the product, extending 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, forming a V-shape such 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 Figure 2, the knuckle 10 is integrally equipped with an arm fastening portion 18 at its lower part. The lower arm is fastened to this arm fastening portion 18. Other parts use the same reference numerals as in Figure 1, and detailed explanations are omitted.

[0026] As shown in Figure 3, the first reinforcing rib 16 and the second reinforcing rib 17 are integrally formed in the intermediate part 11 of the product, extending from the axle fastening part 12 to the damper fastening part 13. Other parts use the same reference numerals as in Figure 1, and detailed explanations are omitted.

[0027] The knuckle casting that forms the basis of the knuckle 10 described above is explained below. As shown in Figure 4, the knuckle casting 20 consists of a guide portion 22 and a product portion 23 formed along the flow of molten metal 21. The guide portion 22 solidifies after the product portion 23 solidifies. The area near the center of the guide portion 22 becomes the final solidified portion 29.

[0028] Once solidification is complete, the formulation section 22 is separated from the product section 23 by the separation line 24. The processing unit 22 is sent to the remelting process, and the product unit 23 is machined to obtain the knuckle 10 as described in Figures 1 to 3.

[0029] The product section 23 includes an intermediate section 26, a first fastening section 27 integrally formed at one end of the intermediate section 26 (the side facing the guide section 22), 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 on the intermediate section 26 so as to extend from the first fastening section 27 to the second fastening section 28.

[0030] By machining the product part 23, the knuckle 10 shown in Figure 2 is obtained. Thus, the first fastening part 27 corresponds to the part that fastens the axle (Figure 1, axle fastening part 12), and the second fastening part 28 corresponds to the part that fastens the damper (Figure 1, damper fastening part 13).

[0031] The product section 23 further integrally includes a section 33 that extends to the right from the intermediate section 26. A rod fastening section (Figure 1, reference numeral 14) is formed on this extending section 33 in a later process.

[0032] Furthermore, the first rib 31 and the second rib 32 are arranged in a V-shape, non-parallel to the center line 34 passing through the center of the first fastening portion 27 and the center of the second fastening portion 28, such 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 this embodiment, both the first rib 31 and the second rib 32 are made non-parallel to the center line 34. However, one of them may be made non-parallel to the center line 34, and the other may be made parallel to the center line 34 (including being approximately parallel). The point is that it should form a V shape.

[0034] To examine the advantages of the V-shaped arrangement of the first rib 31 and second rib 32 of the present invention, a knuckle casting with a pair of ribs arranged in parallel is used as a "comparative example". As shown in Figure 5, the knuckle casting 120 in the comparative example consists of a shaping section 122 and a product section 123. The product section 123 comprises an intermediate section 126, a first fastening section 127, a second fastening section 128, a first rib 131 and a second rib 132 integrally formed on the intermediate section 126 so as to extend from the first fastening section 127 to the second fastening section 128, and a protruding section 133.

[0035] Furthermore, the first rib 131 and the second rib 132 are parallel to the 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 (example) and the knuckle casting 120 (comparative example) described above will be compared. This comparison will be explained with reference to Figures 6 and 7.

[0037] Figure 6 illustrates the solidification process of the first reinforcing rib. Figure 6(a) shows knuckle casting 120 (comparative example), and Figure 6(b) is a diagram illustrating the solidification time in the cross-section along line bb in Figure 6(a). In Figure 6(b), the solidification time t1 in the shaded area is 10-18 seconds. The solidification time t2 in the area with numerous dots is 18-22 seconds. In other words, in the intermediate section including the first rib 131, solidification progresses (is directed) from the left and right surface layers towards the center. The distance D1 is defined as the distance between the left solidification time t2 area and the right solidification time t2 area.

[0038] Figure 6(c) shows a knuckle casting 20 (example), and Figure 6(d) is a diagram illustrating the solidification time in the cross-section along line dd in Figure 6(c). In Figure 6(d), the solidification time t1 in the shaded area is 10-18 seconds. The solidification time t2 in the area with numerous dots is 18-22 seconds. In other words, in the intermediate section including the first rib 31, solidification progresses (is directed) from the left and right surface layers towards the center. The distance D2 is defined as the distance between the left solidification time t2 area and the right solidification time t2 area.

[0039] Distance D2 is significantly smaller than distance D1. In addition, in Figure 6(d), the tip of the solidification time t2 area exhibits a "V" shape, clearly indicating the division of the solidification direction. In contrast, in Figure 6(b), the division of the solidification direction is not clearly defined.

[0040] In Figure 6(d), the boundary between the solidification directions is clear, so the unsolidified molten metal is pushed out to the first fastening part 27 and the second fastening part 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 orientations is not clearly defined, making it easier for casting defects such as voids to remain.

[0041] The above trends are also examined in Figure 4. In Figure 4, after the molten metal 21 has been filled into the mold during the casting process, it is cooled by the mold and solidification of the molten metal 21 begins. 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 tend to occur in the final part of the solidification due to the solidification shrinkage of the metal.

[0042] As explained in Figure 6(d), the unsolidified molten metal moves towards the first fastening portion 27 and the second fastening portion 28. In Figure 4, the molten metal heading towards the first fastening portion 27 proceeds towards the final solidification portion 29, and the molten metal heading towards the second fastening portion 28 proceeds towards the center of the second fastening portion 28. The center of the second fastening portion 28 becomes the delayed solidification portion 30 on the product side.

[0043] Shrinkage cavities are likely to occur in the final solidification section 29 and the delayed solidification section 30 on the product side. Due to the clear solidification directionality, the locations where shrinkage cavities occur are limited to the final solidification section 29 and the delayed solidification section 30 on the product side. Since the final solidified portion 29 is included in the formula portion 22 which is divided by the dividing line 24, it does not affect the product portion 23. Furthermore, the delayed solidification portion 30 on the product side is removed by cutting when machining the machined hole (Figure 1, reference numeral 19).

[0044] In other words, solidification begins from the intermediate section 26. As a result, the solidification directionality is controlled, preventing casting defects such as shrinkage cavities from occurring in the product section 23, including the intermediate section 26. Consequently, improvements in internal quality, strength, productivity, and castability are achieved. In contrast, in the comparative examples described in Figures 6(a) and (b), the boundary between solidification orientations is not clear, so there remains a risk of shrinkage cavities occurring in the product compared to the examples described in Figures 6(c) and (d).

[0045] Figure 7 illustrates the solidification process of the second reinforcing rib. Figure 7(a) shows knuckle casting 120 (comparative example), and Figure 7(b) is a diagram illustrating the solidification time in the cross-section along line bb in Figure 7(a). In Figure 7(b), the solidification time t1 in the shaded area is 10-16 seconds. The solidification time t3 in the area with numerous dots is 16-18 seconds. The distance D3 is defined as the distance between the left solidification time t3 area and the right solidification time t3 area. Furthermore, the second rib 132 is less likely to solidify than the first rib because it is affected by the protruding portion 133, which has a large heat capacity.

[0046] Figure 7(c) shows a knuckle casting 20 (example), and Figure 7(d) is a diagram illustrating the solidification time in the cross-section along line dd in Figure 7(c). In Figure 7(d), the solidification time t1 in the shaded area is 10-16 seconds. The solidification time t3 in the area with numerous dots is 16-18 seconds. Let D4 be the distance between the left coagulation time t3 area and the right coagulation time t3 area. Furthermore, the second rib 32 is less likely to solidify than the first rib because it is affected by the protruding portion 33, which has a large heat capacity.

[0047] Distance D4 is significantly smaller than distance D3. In addition, in Figure 7(d), the tip of the solidification time t3 area exhibits a "V" shape, clearly indicating the division of the solidification direction. In contrast, in Figure 7(b), the division of the solidification direction is not clearly defined.

[0048] In Figure 7(d), the boundary between the solidification directions is clear, so the unsolidified molten metal is pushed out to the first fastening part 27 and the second fastening part 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 the solidification directions is not clearly defined, making it easier for casting defects such as voids to remain.

[0049] In other words, as shown in Figures 7(c) and (d), solidification begins from the middle section. As a result, the solidification directionality is controlled, preventing casting defects such as shrinkage cavities from occurring in the product, including the middle section. Consequently, improvements in internal quality, strength, and productivity can be achieved. In contrast, in the comparative examples described in Figures 7(a) and (b), the boundary between solidification orientations is not clear, so there remains a risk of shrinkage cavities occurring in the product compared to the examples described in Figures 7(c) and (d).

[0050] Figures 6 and 7 show a significant difference in coagulation directionality between the comparative example and the example. We will try to estimate the reason for this difference. In Figure 5 (Comparative Example), since the first rib 131 and the second rib 132 are parallel, the longitudinal axis 131B of the first rib 131 is not directed toward the final solidification portion 129 in the gating portion 127. Similarly, the longitudinal axis 132B of the second rib 132 is not directed toward the final solidification portion 129 in the gating portion 127. Some of the unsolidified molten metal flows along the longitudinal axes 131B and 132B toward the pouring section 127, but not toward the final solidification section 129. Therefore, as shown in Figures 6(b) and 7(b), the dividing line for solidification direction 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 solidification portion 29, and the longitudinal axis 32B of the second rib 32 pointing toward the final solidification portion 29. A portion of the unsolidified molten metal flows along the longitudinal axes 31B and 32B towards the final solidification area 29. As a result, the division of the solidification direction becomes clear, as shown in Figures 6(d) and 7(d).

[0052] Next, we investigated the preferred sizes for the rib spacings W1 and W2 shown in Figure 4. 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. The castability of Models 1 to 4 was then investigated. 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 V-shape effect was not achieved, resulting in minimal improvement in castability. The result is a failure (×). In Model 2, W2 was set to 1.28. A sufficient V-shape effect was achieved, resulting in good castability. The result is positive (〇). In Model 3, W2 was set to 1.33. A sufficient V-shape effect was achieved, resulting in good castability. The result is positive (〇). In Model 4, W2 was set to 1.45. The angle formed by the V-shape increased, affecting the flow of hot water. The result is △.

[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 in the range of 1.28 to 1.33.

[0056] Next, a more preferred embodiment will be described. As shown in Figure 8, the plan section 22 is configured to include the final solidification section 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 coincide with the final solidification section 29. The intersection does not need to be at the center of the final solidification section 29; it may be at the edge of the final solidification section 29 as long as it is within the section.

[0057] Because the unsolidified molten metal moves along the longitudinal axes 31B and 32B towards the final solidification area 29, the solidification directionality becomes clearer, and the occurrence of casting defects can be more reliably avoided.

[0058] In this embodiment, an axle was fastened to the first fastening portion 27, but it is also permissible to fasten other arms or rods to the first fastening portion 27. Similarly, although a damper is fastened to the second fastening portion 28, it is permissible to fasten other arms or rods to the second fastening portion 28. [Industrial applicability]

[0059] The present invention is suitable for knuckles that hold wheels. [Explanation of Symbols]

[0060] 10...Knuckle, 12...Axle fastening section, 13...Damper fastening section, 16...First reinforcing rib, 17...Second reinforcing rib, 20...Knuckle casting, 21...Molten metal, 22...Shaping section, 23...Product section, 24...Separation line, 26...Intermediate section, 27...First fastening section, 28...Second fastening section, 29...Final solidification section, 31...First rib, 31B...Longitudinal axis of the first rib, 32...Second rib, 32B...Longitudinal axis of the second rib, 34...Centerline, W1...Rib spacing on the first fastening section side, W2...Rib spacing on the second fastening section side.

Claims

1. A knuckle casting from which a knuckle product can be obtained by machining, This knuckle casting is a casting comprising a design part and a product part formed along the flow of molten metal, and is designed so that the design part solidifies after the product part solidifies, and after solidification, the design part is separated from the product part, and the design part is sent to a remelting process, and the product part is subjected to the machining process. 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.

3. A knuckle including a product intermediate portion, an axle fastening portion formed integrally with one end of the product intermediate portion and to which an axle is fastened, and a damper fastening portion formed integrally with the other end of the product intermediate portion and to which a damper is fastened, The knuckle includes a first reinforcing rib and a second reinforcing rib that are integrally formed with the product intermediate portion and extend from the axle fastening portion to the damper fastening portion, When the rib spacing between the first reinforcing rib and the second reinforcing rib on the axle fastening portion side is set to 1.0, the rib spacing between the first reinforcing rib and the second reinforcing rib on the damper fastening portion side is set to 1.28 to 1.33, A knuckle characterized in that the first reinforcing rib and the second reinforcing rib are non-parallel and arranged in a V-shape so that the rib spacing on the axle fastening portion side is narrower than the rib spacing on the damper fastening portion side.

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