Bracket for stabilizer, method for designing bracket for stabilizer, method for manufacturing bracket for stabilizer, and stabilizer device

Abstract

A bracket for a stabilizer according to the present invention comprises a first member and a second member that hold a bush in a state of being compressed in a second direction intersecting a first direction. The first member has a contact part that comes into contact with the bush, a first connection plate part that extends from the contact part in a third direction intersecting the first direction and the second direction, and a through-hole provided in the first connection plate part. The second member has a recess that can accommodate the bush, a second connection plate part that extends in the third direction with respect to the bush and overlaps the first connection plate part, and a crimped part that is provided to the second connection plate part and is crimped so as to be inserted into the through-hole. The inner peripheral surface of the through-hole has a straight surface that extends in the second direction, and an inclined surface that is inclined with respect to the surface of the first connection plate part.

Description

Bracket for stabilizer, design method for bracket for stabilizer, manufacturing method for bracket for stabilizer, and stabilizer device

[0001] An embodiment of the present invention relates to a bracket for a stabilizer, a method for designing a bracket for a stabilizer, a method for manufacturing a bracket for a stabilizer, and a stabilizer device.

[0002] Generally, a stabilizer device is used to suppress the roll motion of a vehicle body that occurs when a vehicle such as an automobile vibrates, and performs functions such as reducing vibrations that occur when the vehicle is traveling, suppressing the roll motion of the vehicle, and maintaining the left-right balance of the vehicle body to improve driving stability.

[0003] Patent Document 1 discloses a stabilizer bracket that holds a bushing having a fitting hole into which a vehicle stabilizer is fitted and is attached to a vehicle frame. The stabilizer bracket sandwiches and compresses the bushing between an upper bracket having a recess that can accommodate the bushing and a lower bracket that abuts against the bushing. Furthermore, flanges on each of the upper and lower brackets are provided with through-holes, and rivets provided around the periphery of the through-hole in the upper bracket are fastened to the through-hole in the lower bracket by crimping them.

[0004] US Patent Application Publication No. 2018 / 0141402

[0005] The crimping structure of a stabilizer bracket is required to withstand destruction before being assembled into a vehicle. Therefore, the crimping structure of a stabilizer bracket is required to have high strength. However, the strength of the crimping structure of a stabilizer bracket cannot be verified without conducting a destructive test after the crimping structure is formed. Therefore, a design method for a stabilizer bracket that can predict the breaking load is required.

[0006] An object of one embodiment of the present invention is to improve the strength of the crimping structure of a stabilizer bracket, to provide a design method for a stabilizer bracket that is capable of predicting the breaking load, or to provide a manufacturing method for a stabilizer bracket.

[0007] In one embodiment of the present invention, the stabilizer bracket is a stabilizer bracket that holds a bush having a fitting hole into which a vehicle stabilizer extending in a first direction is fitted, and is attached to a vehicle body frame, and includes a first member and a second member that sandwich and compress the bush in a second direction that intersects with the first direction, the first member having an abutment portion that abuts against the bush, a first connecting plate portion that extends from the abutment portion in a third direction that intersects with the first and second directions, and a through hole provided in the first connecting plate portion, and the second member has a recess that can accommodate the bush, and a second member that extends in the third direction relative to the bush, The connector has a second connecting plate that overlaps the first connecting plate, and a crimped portion that is provided on the second connecting plate and crimped so as to be inserted into the through hole, the inner peripheral surface of the through hole has a straight surface that extends in a second direction and an inclined surface that is inclined with respect to the surface of the first connecting plate, the crimped portion has a straight portion that extends along the straight surface and a locking portion that locks on the inclined surface, and the breaking load W1 expressed using the hole diameter φD1 (mm) on the inclined surface, the hole diameter φD2 (mm) on the straight surface, and the length L1 (mm) of the straight surface in the third direction is expressed by the following formula (1) and satisfies formulas (2) to (5): W1 = a{(φD1 - φD2) × L1} ２ +b{(φD1-φD2)×L1}+c (1) However, the ranges of coefficient a, coefficient b, constant c, and withstand load W2 are as follows: a = -233225 to -70334 (2) b = 112363 to 326155 (3) c = -104232 to -35052 (4) W2 ≥ 7700N (5)

[0008] In the stabilizer bracket, the hole diameter φD2 in the inclined surface is the hole diameter at the lower end of the locking portion in the inclined surface.

[0009] In the stabilizer bracket, the first connecting plate portion has an overlapping surface facing the second connecting plate portion, and the length L1 of the straight surface is the length from the end of the overlapping surface to the end of the inclined surface.

[0010] In the stabilizer bracket, the angle of the inclined surface relative to the surface of the first connecting plate portion is equal to or greater than 1° and equal to or less than 4°.

[0011] In one embodiment of the present invention, a design method for a stabilizer bracket is a design method for a stabilizer bracket that holds a bush having a fitting hole into which a vehicle stabilizer extending in a first direction is fitted, and is attached to a vehicle body frame, the design method comprising: a first member and a second member that hold the bush in a sandwiched and compressed state in a second direction intersecting the first direction; the first member has an abutment portion that abuts against the bush, a first connecting plate portion that extends from the abutment portion in a third direction intersecting the first direction and the second direction, and a through hole provided in the first connecting plate portion; and the second member has a recess that can accommodate the bush, and a second member that has a recess that can abut against the bush in the third direction intersecting the bush. The through hole has an inner peripheral surface that has a straight surface extending in the second direction and an inclined surface that is inclined relative to the surface of the first connecting plate, and the inclined surface has a straight portion that extends along the straight surface and a locking portion that locks on the inclined surface, and the hole diameter φD1 (mm) on the inclined surface, the hole diameter φD2 (mm) on the straight surface, and the length L1 (mm) of the straight surface in the third direction are set so that the breaking load W1 expressed by the following equation (1) satisfies equations (2) to (5): W1 = a{(φD1 - φD2) × L1} ２ +b{(φD1-φD2)×L1}+c (1) However, the ranges of coefficient a, coefficient b, constant c, and withstand load W2 are as follows: a = -233225 to -70334 (2) b = 112363 to 326155 (3) c = -104232 to -35052 (4) W2 ≥ 7700N (5)

[0012] In the design method for the stabilizer bracket, the hole diameter φD1 (mm) on the inclined surface, the hole diameter φD2 (mm) on the straight surface, and the length L1 (mm) in the third direction of the straight surface are set so that the breaking load W1 expressed by equation (1) satisfies equations (2) to (5), by setting the length of the hole diameter φD2, setting each of the coefficient a, coefficient b, and constant c in equation (1) based on the length of the hole diameter φD2 and equations (3) to (5), setting the conditions for the hole diameter φD1 and length L1, calculating the range of (φD1-φD2) x L1 based on the relationship between equation (1) in which the coefficient a, coefficient b, and constant c are set, and equation (2), setting the range of the hole diameter φD1 and length L1, and calculating (φD1-φD2) x L1 based on the set hole diameter φD1, hole diameter φD2, and length L1, thereby determining whether the breaking load W1 is equal to or greater than the withstand load W2.

[0013] In the design method for the stabilizer bracket, the breaking load W1 is predicted under the conditions of hole diameter φD1, hole diameter φD2, and length L1 in equation (1) in which coefficients a, b, and c are set.

[0014] In the above-described method for designing a bracket for a stabilizer, the hole diameter φD1 in the inclined surface is the hole diameter at the position where the inclined surface comes into contact with the lower end of the locking portion.

[0015] In the above-described design method for a stabilizer bracket, the first connecting plate portion has an overlapping surface facing the second connecting plate portion, and the length L1 of the straight surface is the length from the end of the overlapping surface to the end of the inclined surface.

[0016] In the above-described method for designing a bracket for a stabilizer, the angle of the inclined surface is equal to or greater than 1° and equal to or less than 4° with respect to the surface of the first connecting plate portion.

[0017] A method for manufacturing a bracket for a stabilizer according to one embodiment of the present invention manufactures a bracket for a stabilizer by using the above-described method for designing a bracket for a stabilizer.

[0018] A stabilizer device according to one embodiment of the present invention includes a vehicle stabilizer extending in a first direction, a bushing having a fitting hole into which the vehicle stabilizer is fitted, and the above-mentioned stabilizer bracket that holds the bushing and is attached to the vehicle frame.

[0019] According to one embodiment of the present invention, it is possible to improve the strength of the crimping structure of a bracket for a stabilizer, to provide a design method for a bracket for a stabilizer that is capable of predicting the breaking load, or to provide a manufacturing method for a bracket for a stabilizer.

[0020] 1 is a perspective view of a stabilizer device according to one embodiment of the present invention; FIG. 2 is a cross-sectional view of the stabilizer bracket 1 taken along line A1-A2 of FIG. 1; FIG. 3 is a diagram illustrating a crimping structure of a stabilizer bracket according to one embodiment of the present invention; FIG. 4 is a diagram illustrating a crimping structure of a stabilizer bracket according to one embodiment of the present invention; FIG. 5 is a diagram illustrating a manufacturing method of a crimping structure of a stabilizer bracket according to one embodiment of the present invention; FIG. 6 is an optical microscope photograph showing an enlarged cross section of a crimping structure manufactured by a manufacturing method of a crimping structure of a stabilizer bracket; FIG. 7 is a diagram illustrating the relationship between (φD1-φD2)×L1 and a breaking load; FIG. 8 is a diagram illustrating the relationship between (φD1-φD2)×L1 and a breaking load; FIG. 9 is a diagram illustrating the relationship between (φD1-φD2)×L1 and a breaking load; FIG. 10 is a diagram illustrating the relationship between (φD1-φD2)×L1 and a breaking load; FIG. 11 is a diagram illustrating the relationship between (φD1-φD2)×L1 and a breaking load;

[0021] Hereinafter, each embodiment of the invention disclosed in this application will be described with reference to the drawings. However, the present invention can be embodied in various forms without departing from the gist thereof, and should not be construed as being limited to the description of the embodiments exemplified below. Furthermore, in this specification and each drawing, elements having the same functions as those described with reference to the previous drawings will be assigned the same reference numerals, and duplicate explanations may be omitted.

[0022] 1. Structure of the Stabilizer Device In this embodiment, a stabilizer device 10 according to one embodiment of the present invention will be described with reference to Figures 1 to 4. Figure 1 is a perspective view of the stabilizer device 10 according to one embodiment of the present invention. The stabilizer device 10 includes a stabilizer bracket 1, a stabilizer 50 for a vehicle, and a bushing 54.

[0023] 1, for the sake of explanation, the arrows shown in the figure indicate the X-axis direction, the Y-axis direction, and the Z-axis direction. In the figure, the Y-axis direction is perpendicular to the X-axis direction, and the Z-axis direction is perpendicular to the XY plane. The relationship between the three directions, the X-axis direction, the Y-axis direction, and the Z-axis direction, is the same in other figures referred to in this embodiment, unless otherwise specified.

[0024] The stabilizer 50 includes a torsion section 50a extending in the left-right direction (X-axis direction) of the vehicle, and a pair of arm sections 50b extending from both left-right ends of the torsion section 50a toward the rear of the vehicle (Y-axis direction). The torsion section 50a and the arm sections 50b are formed in a tubular shape. The torsion section 50a and the arm sections 50b are formed to be elastically deformable. A suspension device 51 is connected to the rear end of the arm sections 50b.

[0025] The suspension device 51 includes a support portion 52 that rotatably supports a wheel (not shown), and a shock absorber 53 attached to the support portion 52. The support portion 52 includes an upper arm 52a, a lower arm 52b, and an axle 52c. The arm portion 50b of the stabilizer 50 is connected to the lower arm 52b.

[0026] The bushing 54 is made of, for example, a rubber material. A fitting hole 54a into which the stabilizer 50 is fitted is formed in the bushing 54. The fitting hole 54a is formed in the center of the bushing 54 when viewed from the left and right direction. The left and right ends of the torsion portion 50a are fitted into the fitting hole 54a. Two bushings 54 are provided spaced apart in the left and right direction. Note that multiple bushings 54 may also be provided spaced apart in the up and down direction, for example. The stabilizer bracket 1 holds the bushings 54 and is attached to the vehicle body frame F.

[0027] 2. Structure of the Stabilizer Bracket Figure 2 is a cross-sectional view of the stabilizer bracket 1 shown in Figure 1 taken along line A1-A2. The stabilizer bracket 1 includes a first member 11 and a second member 12 that are separate (divided) in the Z-axis direction. The first member 11 and the second member 12 sandwich and compress the bushing 54 in the Z-axis direction. The Z-axis direction is perpendicular to the direction in which the central axis O of the fitting hole 54a extends. For convenience of explanation, the side of the first member 11 along the Z-axis direction will be referred to as the lower side, and the side of the second member 12 along the Z-axis direction will be referred to as the upper side. The direction in which the central axis O of the fitting hole 54a extends will be referred to as the left-right direction (X-axis direction), and the direction perpendicular to the Z-axis direction and the left-right direction will be referred to as the front-rear direction (Y-axis direction).

[0028] The first member 11 and the second member 12 are made of steel. The Young's modulus of the steel is, for example, 200 GPa or more and 220 GPa. Examples of materials suitable for the first member 11 and the second member 12 include iron, titanium, aluminum, magnesium, and alloys thereof. Here, alloys refer to, for example, iron-based alloys (including stainless steel), Ti-based alloys, Al-based alloys, and Mg alloys. More preferred examples of materials suitable for the first member 11 and the second member 12 include steel, iron-based alloys, aluminum, aluminum alloys, magnesium, and magnesium alloys, with steel being the most preferred. Such steel materials are, for example, steel materials standardized by the Japanese Industrial Standards (JIS) and the like, and specific examples of steel materials include hot-rolled steel plate materials for automobile structures (SAPH440) specified in JIS G 3113, and hot-rolled high-tensile steel plate materials for automobile processing (SPFH490, SPFH540, SPFH590) specified in JIS G 3134.

[0029] The first member 11 has an abutment portion 13 that abuts against the bush 54, a first connecting plate portion 15 that extends from the abutment portion 13 in the Y-axis direction, and a through hole 22 provided in the first connecting plate portion 15. The first member 11 has a pair of first connecting plate portions 15, and each of the pair of first connecting plate portions 15 protrudes in the Y-axis direction from the abutment portion 13. Each of the pair of first connecting portions is formed in a plate shape with the front and back surfaces facing in the Z-axis direction. In other words, the entire first member 11, including the abutment portion 13 and the pair of first connecting plate portions 15, is formed in a flat plate shape.

[0030] The second member 12 has a recess 14 capable of accommodating a bushing 54, a second connecting plate 16 extending in the Y-axis direction relative to the bushing 54 and overlapping the first connecting plate 15, and a crimping portion 23 provided on the second connecting plate 16 and crimped to insert into the through-hole 22. The recess 14 is formed in a half-cylindrical shape that opens downward. In other words, the recess 14 has a shape in which the lower portion is removed by a dividing surface extending in the axial direction of a cylindrical shape extending in the X-axis direction. The second member 12 has a pair of second connecting plates 16, each protruding in the Y-axis direction from the recess 14. Each of the pair of second connecting plates 16 is formed in a plate shape with the front and back surfaces facing the Z-axis direction.

[0031] The pair of first connecting plate portions 15 and the pair of second connecting plate portions 16 are overlapped with each other. The recessed portion 14 and the abutting portion 13 press the inner peripheral surface of the fitting hole 54a against the outer peripheral surface of the torsion portion 50a. The surface of the first connecting plate portion 15 facing the second connecting plate portion 16 is called the first overlapping surface 17. The surface of the second connecting plate portion 16 facing the first connecting plate portion 15 is called the second overlapping surface 18.

[0032] The inner peripheral surface of the through hole 22 has a straight surface 22a extending in the Z-axis direction and an inclined surface 22b inclined relative to the back surface of the first connecting plate portion 15. The crimped portion 23 is crimped so as to be inserted into the through hole 22. The crimped portion 23 has a straight portion 23a extending along the straight surface 22a and a locking portion 23b that locks on the inclined surface 22b. The straight portion 23a is formed in a cylindrical shape, and the locking portion 23b is formed in a truncated conical shape. The inside of the cylinder formed by the straight portion 23a and the locking portion 23b is also referred to as a through hole 25.

[0033] In this manner, by inserting the crimping portion 23 of the second connecting plate portion 16 into the through hole 22 of the first connecting plate portion 15 and crimping it, the bushing 54 is sandwiched and compressed between the recess 14 and the abutting portion 13. This allows the crimping structure 30 to be formed between the first member 11 and the second member 12. The crimping structure 30 causes the outer peripheral surface of the torsion portion 50a to be pressed against the inner peripheral surface of the fitting hole 54a. Therefore, the distance between the lower surface (inner surface) at the upper end of the recess 14 and the upper surface of the abutting portion 13 is smaller than the vertical length of the bushing 54 when it is not sandwiched and compressed between the recess 14 and the abutting portion 13.

[0034] A bolt B is provided so as to pass through the inside of the cylindrical crimping portion 23. The side of the bolt B opposite the second overlapping surface 18 of the second connecting plate portion 16, i.e., the upper surface, serves as a fastening surface 19 that is fastened in the Z-axis direction by the head of the bolt B. In other words, the fastening surface 19 is a biased surface that is biased downward by the head of the bolt B. The side of the first connecting plate portion 15 opposite the first overlapping surface 17, i.e., the lower surface, serves as a mounting surface 21 that is attached to the body frame F.

[0035] 3. Crimping Structure of Stabilizer Bracket Next, the crimping structure 30 of the stabilizer bracket 1 will be described in detail with reference to Figures 3 and 4. Figures 3 and 4 are diagrams illustrating the crimping structure 30 of the stabilizer bracket according to one embodiment of the present invention.

[0036] 3 and 4 , the inner circumferential surface of the through hole 22 of the first member 11 has a straight surface 22a extending in the Z-axis direction and an inclined surface 22b inclined relative to the first overlapping surface 17 of the first connecting plate portion 15. The straight surface 22a is continuous with the first overlapping surface 17 and is a straight, cylindrical surface with a central axis extending in the Z-axis direction, and the inner diameter of the straight surface 22a is constant in the Z-axis direction. The inclined surface 22b is continuous with the straight surface 22a and has an inclination that increases in diameter from the straight surface 22a toward the mounting surface 21. The diameter of the cylindrical hole in the straight surface 22a is referred to as the hole diameter φD2.

[0037] The crimping portion 23 of the second member 12 has a straight portion 23a extending along the straight surface 22a and a locking portion 23b that locks onto the inclined surface 22b. The straight portion 23a is cylindrical, and the inner diameter of the straight portion 23a is constant in the Z-axis direction. The locking portion 23b locks onto the inclined surface 22b. The locking portion 23b is continuous with the straight portion 23a and has a truncated conical shape that widens in diameter from the straight portion 23a toward the mounting surface 21. The length L3 of the straight portion 23a refers to the length from the end of the fastening surface 19 to the end of the inclined surface 22b. The length L4 of the locking portion 23b refers to the length from the end of the straight portion 23a to the end P1 of the locking portion 23b on the mounting surface 21 side. The hole diameter φD1 is the hole diameter at the end P2 of the locking portion 23b on the inclined surface 22b side. The hole diameter φD1 is larger than φD2.

[0038] As shown in Figure 4, the length L2 of the inclined surface 22b is longer than the length L1 of the straight surface 22a, which not only makes it possible to firmly engage the crimping portion 23 with the first connecting plate portion 15, but also makes it less likely for this crimping portion 23 to protrude downward from the mounting surface 21 toward the vehicle frame F.

[0039] On the inner circumferential surface of the through hole 22 shown in FIG. 4 , the length L1 of the straight surface 22a refers to the length from the end of the first overlapping surface 17 to the end of the inclined surface 22b. Furthermore, the length L2 of the inclined surface 22b refers to the length from the end of the straight surface 22a to the end of the mounting surface 21. The length L1 of the straight surface 22a is shorter than the length L2 of the inclined surface 22b. If the end P1 of the locking portion 23b on the mounting surface 21 side is positioned below the mounting surface 21 in the Z-axis direction, the locking portion 23b will come into contact with the vehicle body. Therefore, it is preferable that the end P1 of the locking portion 23b on the mounting surface 21 side be positioned at the same position as the mounting surface 21 or above the mounting surface 21 in the Z-axis direction.

[0040] As described above, according to the stabilizer bracket 1, the cylindrical crimping portion 23 is provided around the entire inner circumferential surface of the through hole 22, and the crimping portion 23 is crimped and fixed to the second connecting plate portion 16 while fitted into the through hole 22. This makes it possible to restrict the relative movement of the first member 11 and the second member 12 while the bush 54 is sandwiched and compressed between the recess 14 and the abutting portion 13, and the first member 11 and the second member 12 holding the bush 54 can be handled as a single unit.

[0041] 4. Manufacturing Method of the Crimping Structure of the Stabilizer Bracket Next, a manufacturing method of the crimping structure 30 of the stabilizer bracket 1 using the first member 11 and the second member 12 will be described with reference to FIG.

[0042] First, the second connecting plate portion 16 of the second member 12 is subjected to, for example, burring or the like to form a cylindrical crimped portion 23 that extends straight in the Z-axis direction. Then, the crimped portion 23 is inserted into the through hole 22. As shown in FIG. 5 , with the crimped portion 23 fitted into the through hole 22, a truncated conical molding pin 40 having a generatrix extending along the inclined surface 22 b of the through hole 22 is inserted into the crimped portion 23 from below the first member 11 (from the inclined surface 22 b side of the through hole 22 in FIG. 5 ), and the outer peripheral surface of the crimped portion 23 is pressed against the inclined surface 22 b, thereby plastically deforming the tip of the crimped portion 23. This allows the manufacture of the crimped structure 30 for a stabilizer bracket, in which the crimped portion 23 of the second member 12 is crimped into the through hole 22 of the first member 11.

[0043] Fig. 6 shows an optical microscope photograph enlarging a portion of the crimped structure manufactured by the manufacturing method for the crimped structure for a stabilizer bracket. As shown in Fig. 6, the crimped portion 23 of the second member 12 is crimped into the through hole 22 of the first member 11. Also, as shown in Fig. 6, the tip of the crimped portion 23 of the second member 12 is plastically deformed to form the locking portion 23b. In the locking portion 23b, the hole diameter at the end P2 on the inclined surface 22b side is φD1. Also, the cylindrical hole diameter at the straight surface 22a of the first member 11 is φD2.

[0044] 5. Manufacturing Method of Stabilizer Bracket A manufacturing method of the stabilizer bracket 1 will be described. First, the second connecting plate portion 16 of the second member 12 is subjected to, for example, burring or the like to form a cylindrical crimped portion 23 extending straight in the Z-axis direction. Thereafter, the bushing 54 is placed in the recess 14 of the second member 12, and the bushing 54 is brought into contact with the abutment portion 13 of the first member 11, and the crimped portion 23 is inserted into the through hole 22. As shown in FIG. 5 , with the crimped portion 23 fitted into the through hole 22, a truncated conical molding pin 40 having a generatrix extending along the inclined surface 22 b of the through hole 22 is inserted into the crimped portion 23 from below the first member 11 (the inclined surface 22 b side of the through hole 22 in FIG. 5 ). The outer peripheral surface of the crimped portion 23 is pressed against the inclined surface 22 b, thereby plastically deforming the lower portion of the crimped portion 23. By making the thickness t1 of the crimped portion 23 thinner than the thickness t2 of the portion of the second connecting plate 16 that is continuous with the crimped portion 23, the tip of the crimped portion 23 can be easily plastically deformed. This allows the crimped portion 23 to be crimped into the through hole 22. Furthermore, the bushing 54 is held in a compressed state by the recess 14 and the abutting portion 13. This allows the stabilizer bracket to be manufactured.

[0045] 6. Method of Assembling the Stabilizer Device A method of assembling the stabilizer device 10 will be described. The stabilizer 50 is inserted into the fitting hole 54a of the bushing 54, and the bushing 54 is placed in a predetermined position on the stabilizer 50. Thereafter, according to the method of assembling the stabilizer bracket 1 and the bushing 54 described above, the bushing 54 with the stabilizer 50 fitted into the fitting hole 54a is held by the stabilizer bracket 1. By this procedure, the stabilizer device 10 shown in FIG. 1 can be assembled.

[0046] 5, the thickness t1 of the crimped portion 23 is thinner than the plate thickness t2 of the portion of the second connecting plate 16 that is continuous with the crimped portion 23, so that the crimped portion 23 can be easily plastically deformed when crimping the crimped portion 23 to the first connecting plate 15. Furthermore, the thickness t1 of the crimped portion 23 is smaller than the length L4 of the locking portion 23b, so that the crimped portion 23 can be easily plastically deformed when crimping the crimped portion 23 to the first connecting plate 15.

[0047] Therefore, when assembling the stabilizer bracket 1 to the vehicle body frame F, the first member 11 and the second member 12, including the bushing 54, can be handled as a single unit. Furthermore, the bolts B can be inserted into the through holes 22 and 25, and the mounting surface 21 can be attached to the vehicle body frame F while the fastening surface 19 is fastened in the Z-axis direction by the heads of the bolts B. This makes it easy to assemble the stabilizer bracket 1 to the vehicle body frame F. Because the crimping portion 23 is provided integrally with the first connecting plate portion 15, there is no need to attach a separate part such as a collar, and the number of parts can be reduced.

[0048] The stabilizer bar bracket crimping structure 30 is required to withstand destruction before being assembled to a vehicle. Therefore, the stabilizer bar bracket crimping structure is required to have high strength. However, the strength of the stabilizer bar bracket cannot be verified without conducting a destructive test after the crimping structure 30 is formed. Therefore, a design method for a stabilizer bracket that can predict the breaking load is required.

[0049] In this embodiment, the inventors conducted extensive research in light of this point and discovered the following: They discovered that the greater the difference (φD1−φD2) between the hole diameter φD1 of locking portion 23b and the hole diameter φD2 of the straight surface, the greater the breaking load of crimping structure 30. They then discovered that there is a correlation between the breaking load of crimping structure 30 and the value (φD1−φD2)×L1 obtained by multiplying (φD1−φD2) by the length L1 of straight surface 22a, and this led to the present invention.

[0050] 7. Strength of the Crimping Structure First, a plurality of crimping structures 30 for the stabilizer bracket 1 were formed with different design values ​​for the hole diameter φD2 in the straight surface 22a and the length L1 of the straight surface 22a of the first member 11, and the results of measuring the breaking load W1 of each crimping structure 30 will be described. Here, SAPH440 is used as the steel material for the first member 11 and the second member 12.

[0051] First, a plurality of samples were prepared with different hole diameters φD2 in the straight surface 22a and different lengths L1 of the straight surface 22a of the first member 11. Next, the crimping structure 30 for the stabilizer bracket 1 was formed by crimping the second member 12 to the first member 11 according to the manufacturing method of the crimping structure 30 for the stabilizer bracket 1 described above.

[0052] Next, the hole diameter φD1 (mm) of the locking portion 23b of the second member 12 was measured for the manufactured stabilizer bracket crimping structure 30. Thereafter, the first member 11 and the second member 12 were fixed to a destructive test jig, and the destructive test jig on the second member 12 side was pulled up to measure the fracture load W1 applied to the crimping structure 30. The load at which the crimping structure 30 separated into the first member 11 and the second member 12 was defined as the fracture load W1.

[0053] The conditions of multiple samples and the results of measuring the breaking load W1 are shown in Table 1. In Table 1, the length L1 of the straight surface 22a and the hole diameter φD2 in the straight surface 22a are design values. The hole diameter φD1 (mm) in the locking portion 23b is an actual measurement value. Based on the obtained hole diameter φD1, hole diameter φD2, and length L1, the value of (φD1 - φD2) × L1 was calculated.

[0054]

[0055] The relationship between the obtained (φD1-φD2)×L1 and the measured breaking load W1 is shown in FIG. 7. In FIG. 7, the X axis is (φD1-φD2)×L1, and the Y axis is breaking load W1. An approximate curve was also calculated based on the results shown in FIG. 7. The formula for the approximate curve shown in FIG. 7 is shown below. In the following formula, y corresponds to breaking load W1, and x corresponds to (φD1-φD2)×L1. This also applies to the following explanation. y = -85093x ２ +129523x-39481 (A)

[0056] Then, using the equation for the approximation curve shown in equation (A), predicted values ​​of (φD1−φD2)×L1=0.90, 0.95 were calculated.

[0057] Table 2 is a table in which predicted values ​​W when (φD1-φD2)×L1=0.90 and 0.95 are added to Table 1.

[0058]

[0059] The relationship between (φD1 - φD2) x L1 shown in Table 2 and the measured breaking load W1 and predicted value W is shown in Figure 8. In Figure 8, the X axis is (φD1 - φD2) x L1, and the Y axis is breaking load W1. In Figure 8, 7700 W is shown as the withstand load W2 of the crimping structure 30 with a dotted line. The withstand load W2 is the value of the weight that can be withstood without deformation or destruction against externally applied force or weight. An approximate curve was also calculated based on the results shown in Figure 8. The formula for the approximate curve shown in Figure 8 is as follows: y = -85191x ２ +129660x-39529 (B)

[0060] The above results suggest that the relationship between (φD1-φD2)×L1 and the breaking load W1 can be expressed by the following polynomial: W1=a{(φD1-φD2)×L1} ２ +b{(φD1-φD2)×L1}+c Formula (1)

[0061] Next, in order to determine the ranges of the coefficients a, b, and c in equation (1), an approximate curve was calculated based on the relationship between (φD1-φD2) x L1 and the breaking load W1 for each hole diameter φD2 on the straight surface 22a. The results are explained with reference to Figures 9 to 12.

[0062] Figure 9 shows the relationship between (φD1 - φD2) x L1 and the breaking load W1 when the hole diameter φD2 = 12.5 mm. Note that in the results shown in Figure 9, the hole diameter φD2 = 12.5 mm includes both the measured value and the predicted value. In Figure 9, the withstand load W2 of the crimping structure 30 is indicated by a dotted line as 7700 W. An approximate curve was also calculated based on the results shown in Figure 9. The formula for the approximate curve shown in Figure 9 is as follows: y = -111397x ２ +171991x-56229 (C)

[0063] In this case, if the load capacity W2 of the crimping structure 30 is 7700 N, the range of (φD1-φD2)×L1 is expressed as follows: (φD1-φD2)×L1=0.6256 to 0.9184 Therefore, by satisfying (φD1-φD2)×L1=0.6256 to 0.9184, the crimping structure 30 can have a load capacity W2 of 7700 or more.

[0064] Figure 10 shows the relationship between (φD1 - φD2) x L1 and the breaking load W1 when the hole diameter φD2 = 12.7 mm. In Figure 10, the withstand load W2 of the crimping structure 30 is indicated by a dotted line as 7700 W. An approximation curve was also calculated based on the results shown in Figure 10. The formula for the approximation curve shown in Figure 10 is as follows: y = -70334x ２ +112363x-35052 (D)

[0065] In this case, if the load capacity W2 of the crimping structure 30 is 7700 N, the range of (φD1-φD2)×L1 is expressed as follows: (φD1-φD2)×L1=0.6250 to 0.9726 Therefore, by satisfying (φD1-φD2)×L1=0.6250 to 0.9726, the crimping structure 30 can have a load capacity W2 of 7700 or more.

[0066] Figure 11 shows the relationship between (φD1 - φD2) x L1 and the breaking load W1 when the hole diameter φD2 = 12.9 mm. In Figure 11, the withstand load W2 of the crimping structure 30 is indicated by a dotted line as 7700 W. An approximation curve was also calculated based on the results shown in Figure 11. The formula for the approximation curve shown in Figure 11 is as follows: y = -120218x ２+177851x-56050 (E)

[0067] In this case, if the load capacity W2 of the crimping structure 30 is 7700 N, the range of (φD1-φD2)×L1 is expressed as follows: (φD1-φD2)×L1=0.6098 to 0.8696 Therefore, by satisfying (φD1-φD2)×L1=0.6098 to 0.8696, the crimping structure 30 can have a load capacity W2 of 7700 or more.

[0068] Figure 12 shows the relationship between (φD1 - φD2) x L1 and the breaking load W1 when the hole diameter φD2 = 13.1 mm. In Figure 12, the withstand load W2 of the crimping structure 30 is indicated by a dotted line as 7700 W. An approximate curve was also calculated based on the results shown in Figure 12. y = -233225x ２ +326155x-104232 (F)

[0069] In this case, if the load capacity W2 of the crimping structure 30 is 7700 N, the range of (φD1-φD2)×L1 is expressed as follows: (φD1-φD2)×L1=0.6044 to 0.7940 Therefore, by satisfying (φD1-φD2)×L1=0.6044 to 0.7940, the crimping structure 30 can have a load capacity W2 of 7700 or more.

[0070] 9 to 12, it can be seen that the ranges of the coefficient a, coefficient b, and constant c are expressed as follows: a=-233225 to -70334 b=112363 to 326155 c=-104232 to -35052

[0071] From the above results, it can be seen that the breaking load W1, which is expressed using the hole diameter φD1 (mm) of the locking portion 23b in the crimping structure 30, the hole diameter φD2 (mm) of the straight surface 22a, and the length L1 (mm) of the straight surface 22a in the Z-axis direction, is expressed by the following formula (1), and that by satisfying formulas (2) to (5), a stabilizer bracket 1 with high strength can be obtained. W1 = a{(φD1 - φD2) × L1} ２+b{(φD1-φD2)×L1}+c (1) However, the ranges of coefficient a, coefficient b, constant c, and withstand load W2 are as follows: a = -233225 to -70334 (2) b = 112363 to 326155 (3) c = -104232 to -35052 (4) W2 ≥ 7700N (5)

[0072] For example, the hole diameter φD1, hole diameter φD2, and length L1 used in formula (1) are set as follows: The hole diameter φD1 in the locking portion 23b is 12.6 mm to 20.0 mm, preferably 12.6 mm to 13.9 mm, and more preferably 12.6 to 12.8 mm. The hole diameter φD2 in the straight surface 22a is 12.5 mm to 30.0 mm, and preferably 12.8 mm to 13.9 mm. The length L1 of the straight surface 22a in the Z-axis direction is 1.1 mm to 1.9 mm. In formula (1), when the load capacity W2 is 7700 N or more, the range of (φD1 - φD2) x L1 is 0.61 to 0.91.

[0073] The stabilizer bracket 1 is expressed by formula (1) and satisfies formulas (2) to (5), thereby enabling the crimping structure 30 to have a load capacity W2 of 7700 N or more. By using such a stabilizer bracket 1, it is possible to prevent the bracket 1 from being destroyed before being assembled to the vehicle.

[0074] In this embodiment, the case where SAPH440 is used as the steel material has been described, but as long as the steel material has a Young's modulus in the range of 200 GPa to 220 GPa, the strength of the stabilizer bracket 1 can be predicted using equations (1) to (5).

[0075] In this embodiment, the case where the load capacity W2 of the crimping structure 30 is set to 7700 N has been described, but the load capacity W2 may be set as appropriate, for example, between 7570 N and 7700 N. When the load capacity W2 is, for example, 7570 N, the solution for x in the graphs shown in Figures 9 to 12 may be changed as appropriate.

[0076] Furthermore, the greater the thickness t1 of the crimped portion 23 shown in FIG. 5, the greater the breaking load W1 can be.

[0077] The angle of the surface of the straight portion 23a relative to the surface of the straight surface 22a is preferably, for example, 1° or more and 4° or less. This angle depends on the size of the distance (also referred to as clearance) between the straight surface 22a and the surface of the straight portion 23a (the surface opposite the inner periphery of the through hole 25). The larger the clearance, the larger the angle of the surface of the straight portion 23a relative to the surface of the straight surface 22a. Furthermore, the larger the angle of the surface of the straight portion 23a (the inner periphery of the through hole 25) relative to the surface of the straight surface 22a (the inner periphery of the through hole 22), the larger the breaking load W1.

[0078] 8. Method for Designing the Crimping Structure The crimping structure 30 according to one embodiment of the present invention can be designed by the method for designing the crimping structure 30 described below. The method for designing the crimping structure 30 according to one embodiment of the present invention will be described with reference to Fig. 13. The above-described formulas (1) to (5) can also be used in the method for designing the crimping structure 30.

[0079] First, the steel material to be used to form the crimping structure 30 is determined (step S101). The steel material may be selected appropriately from the types of steel materials described above. Next, the length of the hole diameter φD2 in the crimping structure 30 is set (step S102). The hole diameter φD2 is set in the range of 12.5 mm to 13.3 mm. Here, the hole diameter φD2 is set to 13.1 mm.

[0080] Next, the coefficients a, b, and c in equation (1) are set based on the hole diameter φD2 and equations (2) to (4) (step S103). The coefficients a, b, and c are set within a range that satisfies equations (2) to (4), for example, based on the length of the hole diameter φD2. For hole diameters φD2 = 12.5 mm, 12.7 mm, 12.9 mm, and 13.1 mm, the coefficients a, b, and c in equation (1) may be set based on the approximation curves shown in FIGS. 9 to 12. For example, when the hole diameter φD2 = 13.1 mm, the coefficients a, b, and c in equation (1) may be set to -233225, b = 326155, and c = -104232. This allows equation (1) to be rewritten as y = -233225 {(φD1 - φD2) × L1} ２ It can be set as +326155{(φD1-φD2)×L1}-104232.

[0081] Next, based on the relationship between the equation (1) in which the coefficients a, b, and c are set in step S103 and the withstand load W2, the range of (φD1-φD2)×L1 is calculated (step S104): y=-233225{(φD1-φD2)×L1} ２ In the case of +326155{(φD1-φD2)×L1}-104232, when the withstand load W2 is 7700 or more, the range of (φD1-φD2)×L1 can be calculated to be 0.6015 to 0.7969.

[0082] Next, the conditions for the hole diameter φD1 and the length L1 are set (step S105). Here, when the hole diameter φD2 is 13.1 mm, the conditions are set as follows: hole diameter φD1 = 13.2 mm to 13.9 mm, length L1 = 1.1 mm to 1.9 mm.

[0083] Next, (φD1-φD2)×L1 is calculated based on the hole diameter φD1 and length L1 set in step S105, and it is determined whether the calculated breaking load W1 is equal to or greater than the withstand load W2 (step S106). In formula (1), the range of (φD1-φD2)×L1 where the withstand load W2 is 7700 N is 0.6015 to 0.7969. Therefore, if the calculated result of (φD1-φD2)×L1 is within the range of 0.6015 to 0.7969, it can be predicted that the breaking load W1 is 7700 N or greater, and if it is not within the range of 0.6015 to 0.7969, it can be predicted that the breaking load W1 is less than 7700 N.

[0084] When the hole diameter φD2 is 13.1 mm, (φD1 - φD2) x L1 is calculated for hole diameter φD1 = 13.2 mm to 13.9 mm and length L1 = 1.1 mm. Table 3 shows the design values ​​of hole diameter φD1, hole diameter φD2, and length L1, the calculated value of (φD1 - φD2) x L1, and whether or not W ≥ 7700N is satisfied.

[0085]

[0086] From the results shown in Table 3, it can be predicted that when the hole diameter φD2 = 13.1 mm and the length L1 = 1.1 mm, and when the length φD1 = 13.7 mm or 13.8 mm, the withstand load W2 will be W2 ≧ 7700 N.

[0087] Furthermore, equation (1) is W1 = -233225 {(φD1 - φD2) × L1} ２ Using +326155{(φD1-φD2)×L1}-104232, it is possible to predict the breaking load W1 under each condition of the hole diameter φD1, hole diameter φD2, and length L1. In Table 3, the predicted breaking load value [N] is calculated under all conditions, but it is not necessary to calculate the predicted breaking load value [N] under all conditions. Since the range of (φD1-φD2)×L1 can be used to determine the conditions under which the withstand load W2 is 7700 or greater, the predicted breaking load value [N] may be calculated only under the conditions under which the withstand load W2 is 7700 or greater.

[0088] Furthermore, for more detailed prediction, the conditions of the hole diameter φD1 and the length L1 may be set in detail. Table 4 shows the results of calculations performed under the conditions of length L1 = 1.1 mm, 1.3 mm, 1.5 mm, 1.7 mm, and 1.9 mm for hole diameters φD1 = 13.5 mm, 13.6 mm, 13.7 mm, and 13.8 mm, respectively.

[0089]

[0090] As shown in Table 4, when the hole diameter φD2 is 13.1 mm, it is possible to predict the hole diameter φD1 and length L1 that will result in a load capacity W2≧7700 N. Furthermore, when formula (1) is y=−233225x ２ The breaking load W1 can be predicted when +326155x-104232.

[0091] By applying the above-described design method for a stabilizer bracket to a manufacturing method for a stabilizer bracket, a high-strength stabilizer bracket can be manufactured. Furthermore, in the design process of the crimping structure in the manufacturing process for the stabilizer bracket, the fracture load of the crimping structure can be accurately predicted. This allows the stabilizer bracket to be manufactured with a design value that satisfies the load capacity, and allows efficient fracture testing of the manufactured crimping structure.

[0092] According to the design method for the stabilizer bracket 1 according to one embodiment of the present invention, it is possible to determine whether the caulking structure 30 satisfies the load capacity W2 or more. In addition, it is possible to accurately predict the breaking load W1 of the caulking structure 30.

[0093] The technical scope of the present invention is not limited to the embodiments, and various modifications can be made without departing from the spirit of the present invention. Within the scope of the present invention, the components in the embodiments can be replaced with well-known components as appropriate, and the embodiments and modifications can be combined as appropriate.

[0094] 1: stabilizer bracket, 10: stabilizer device, 11: first member, 12: second member, 13: abutment portion, 14: recess, 15: first connecting plate portion, 16: second connecting plate portion, 17: first overlapping surface, 18: second overlapping surface, 19: fastening surface, 21: mounting surface, 22: through hole, 22a: straight surface, 22b: inclined surface, 23: crimping portion, 23a: straight portion, 23b: engaging portion, 25: through hole, 40: molded pin, 50: stabilizer, 50a: torsion portion, 50b: arm portion, 51: suspension device, 52: support portion, 52a: upper arm, 52b: lower arm, 52c: axle, 53: shock absorber, 54: bushing, 54a: fitting hole, B: bolt, F: vehicle body frame

Claims

1. A stabilizer bracket attached to a vehicle frame, the bracket holding a bush having a fitting hole into which a vehicle stabilizer extending in a first direction is fitted, the bracket comprising a first member and a second member sandwiching and compressing the bush in a second direction intersecting the first direction, the first member having a contact portion that contacts the bush, a first connecting plate portion extending from the contact portion in a third direction intersecting the first and second directions, and a through hole provided in the first connecting plate portion, the second member having a recess capable of accommodating the bush, a second connecting plate portion extending in the third direction relative to the bush and overlapping with the first connecting plate portion, and a crimping portion provided in the second connecting plate portion and crimped to be inserted into the through hole, the inner peripheral surface of the through hole having a straight surface extending in the second direction and an inclined surface inclined with respect to the surface of the first connecting plate portion, The stabilizer bracket has a straight portion extending along the straight surface and a locking portion that locks on the inclined surface, and a breaking load W1 expressed using a hole diameter φD1 (mm) on the inclined surface, a hole diameter φD2 (mm) on the straight surface, and a length L1 (mm) of the straight surface in the third direction is expressed by the following formula (1) and satisfies formulas (2) to (5): W1=a{(φD1-φD2)×L1} ２ +b{(φD1-φD2)×L1}+c (1) However, the ranges of coefficient a, coefficient b, constant c, and withstand load W2 are as follows: a = -233225<a<-70334 (2) b = 112363<b<326155 (3) c = -104232<c<-35052 (4) W2≧7700N (5) 2. The stabilizer bracket according to claim 1, wherein the hole diameter φD1 in the inclined surface is the hole diameter at the lower end of the engaging portion in the inclined surface.

3. A stabilizer bracket as described in claim 1, wherein the first connecting plate portion has an overlapping surface facing the second connecting plate portion, and the length L1 of the straight surface is the length from the end of the overlapping surface to the end of the inclined surface.

4. The stabilizer bracket according to claim 1, wherein the angle of the inclined surface relative to the surface of the first connecting plate portion is between 1° and 4°.

5. A method for designing a stabilizer bracket that holds a bush having a fitting hole into which a vehicle stabilizer extending in a first direction is fitted, and that is attached to a vehicle frame, comprising: a first member and a second member that sandwich and hold the bush in a compressed state in a second direction that intersects with the first direction; the first member has an abutment portion that abuts against the bush, a first connecting plate portion that extends from the abutment portion in a third direction that intersects with the first and second directions, and a through hole provided in the first connecting plate portion; the second member has a recess that can accommodate the bush, a second connecting plate portion that extends in the third direction relative to the bush and overlaps with the first connecting plate portion, and a crimping portion that is provided in the second connecting plate portion and crimped so as to be inserted into the through hole; and the inner surface of the through hole has a straight surface that extends in the second direction, and an inclined surface that is inclined with respect to the surface of the first connecting plate portion. a design method for a bracket for a stabilizer, wherein the crimping portion has a straight portion extending along the straight surface and a locking portion that locks on the inclined surface, and the hole diameter φD1 (mm) on the inclined surface, the hole diameter φD2 (mm) on the straight surface, and the length L1 (mm) of the straight surface in the third direction are set so that the breaking load W1 expressed by the following formula (1) satisfies formulas (2) to (5): W1=a{(φD1-φD2)×L1} ２ +b{(φD1-φD2)×L1}+c (1) However, the ranges of coefficient a, coefficient b, constant c, and withstand load W2 are as follows: a = -233225<a<-70334 (2) b = 112363<b<326155 (3) c = -104232<c<-35052 (4) W2≧7700N (5) 6. Setting the hole diameter φD1 (mm) on the inclined surface, the hole diameter φD2 (mm) on the straight surface, and the length L1 (mm) of the straight surface in the third direction so that the breaking load W1 expressed by equation (1) satisfies equations (2) to (5) includes: setting the length of the hole diameter φD2; setting each of the coefficient a, coefficient b, and constant c in equation (1) based on the length of the hole diameter φD2 and equations (2) to (4); setting the conditions for the hole diameter φD1 and the length L1; calculating the range of (φD1-φD2) x L1 based on the relationship between equation (1) in which each of the coefficient a, coefficient b, and constant c is set and equation (2); setting the range of the hole diameter φD1 and the length L1; 6. The design method for a bracket for a stabilizer according to claim 5, wherein the determining step determines whether the breaking load W1 is equal to or greater than the withstand load W2 by calculating (φD1-φD2)×L1 based on the set hole diameter φD1, the hole diameter φD2, and the length L1.

7. A design method for a stabilizer bracket as described in claim 6, in which the breaking load W1 under the conditions of the hole diameter φD1, the hole diameter φD2, and the length L1 is predicted using equation (1) in which coefficient a, coefficient b, and constant c are each set.

8. A method for designing a bracket for a stabilizer as set forth in claim 6, wherein the hole diameter φD1 in the inclined surface is the hole diameter at a position where the inclined surface contacts the lower end of the engaging portion.

9. A design method for a stabilizer bracket as described in claim 6, wherein the first connecting plate portion has an overlapping surface facing the second connecting plate portion, and the length L1 of the straight surface is the length from the end of the overlapping surface to the end of the inclined surface.

10. A design method for a stabilizer bracket as set forth in claim 6, wherein the angle of the inclined surface is between 1° and 4° relative to the surface of the first connecting plate portion.

11. A method for manufacturing a stabilizer bracket, which comprises manufacturing a stabilizer bracket using the design method for a stabilizer bracket according to any one of claims 6 to 10.

12. A stabilizer device comprising: a vehicle stabilizer extending in the first direction; a bush having a fitting hole into which the vehicle stabilizer is fitted; and a stabilizer bracket according to any one of claims 1 to 4, which holds the bush and is attached to the vehicle frame.

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