Method for forming the toe control arm mounting section

Abstract

The present invention provides a method for forming a toe control arm mounting portion that can reliably position an eccentric cam plate. [Solution] The mounting portion of the toe control arm comprises a bracket and a circular eccentric cam plate. A pair of stoppers 3D are formed on each of the pair of bracket plates 3A of the bracket, defining the mounting position of the eccentric cam plate. In the above forming method, a first press is performed on the metal plate 3X which will become the pair of bracket plates 3A, causing each of the pair of stoppers 3D to protrude from the surface of the bracket plate 3A without creating a cut. At this time, a vertical wall 3V is formed on the stopper 3D which restricts the peripheral edge of the eccentric cam plate. Furthermore, a second press is performed on the metal plate 3X to crush the vertical wall 3V formed in the first press, thereby increasing the thickness of the vertical wall 3V.

Description

Technical Field

[0001] The present invention relates to a method for forming a mounting portion on the vehicle body side to which one end of a toe control arm, which is one of the suspension components of a vehicle, is attached.

Background Art

[0002] The following Patent Document 1 discloses a toe control arm mounting portion. A bush is provided at one end of a metal toe control arm. The mounting portion of the toe control arm, that is, the mounting portion of the bush, is generally a bracket formed of a press part of a metal plate. This bracket includes a pair of bracket plates spaced apart in the central axis direction of the bush. The bush is sandwiched between this pair of bracket plates and attached to the bracket by bolts and nuts. At this time, circular eccentric cam plates are also clamped together with respect to the pair of bracket plates.

[0003] The bolt is inserted in the order of one eccentric cam plate, one bracket plate, the collar of the bush, the other bracket plate, and the other eccentric cam plate, and a bolt is screwed onto its tip. The bolt hole of the eccentric cam plate is eccentric with respect to the center of the circle. By changing the rotational positions of the pair of eccentric cam plates, the position of the bush with respect to the bracket can be adjusted. Therefore, by changing the rotational positions of the pair of eccentric cam plates, the suspension geometry can be adjusted.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The rotational position of the eccentric cam plate can be changed relative to the bracket plate, but the mounting position of the eccentric cam plate on the bracket plate is fixed. In other words, the mounting position of the eccentric cam plate relative to the bracket plate is restricted to a predetermined position. For this reason, a pair of opposing stoppers are provided on the bracket plate to restrict the mounting position of the eccentric cam plate.

[0006] There are various methods for forming a stopper, but in Figure 4 of the above-mentioned Patent Document 1, a bent portion is formed by bending the bracket plate, and this bent portion functions as a stopper. However, since the bracket, which is the mounting part for the toe control arm, requires strength and rigidity, the thickness of the bracket plate is not thin. For this reason, the radius of curvature at the corner of the bent portion is relatively large, and there is a risk that the periphery of the circular eccentric cam plate will ride up on this corner and lift off the bracket plate. In this case, the mounting of the bush may loosen, or the bush may not be positioned in the correct position.

[0007] The object of the present invention is to provide a method for forming a toe control arm mounting portion that can reliably position an eccentric cam plate. [Means for solving the problem]

[0008] The mounting portion formed by the toe control arm mounting method according to an aspect of the present invention comprises a bracket having a pair of bracket plates and a circular eccentric cam plate. A bush provided at one end of the toe control arm is sandwiched between the pair of bracket plates. The eccentric cam plate is attached to each bracket plate together with the bush using bolts and nuts. Each bracket plate has a pair of stoppers formed thereon that define the mounting position of the eccentric cam plate relative to that bracket plate. In the above-described forming method, a metal plate that will become the bracket plate is pressed once to make the stoppers protrude from the surface of the bracket plate without creating any cuts. Vertical walls are formed on the stoppers that restrict the peripheral edge of the eccentric cam plate. Furthermore, a second pressing process is performed on the metal plate to crush the vertical walls formed in the first pressing process, thereby increasing the thickness of the vertical walls. [Effects of the Invention]

[0009] According to the molding method described above, a stopper can be formed that reliably positions the eccentric cam plate disposed at the mounting portion of the toe control arm. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a simplified bottom view showing the state in which a toe control arm is attached to a mounting portion formed by the molding method according to the embodiment. [Figure 2] Figure 2 is a cross-sectional view of the bracket plate after preliminary press processing using the molding method described above. [Figure 3] Figure 3 is a cross-sectional view showing the first press working process in the molding method described above. [Figure 4] Figure 4 is a cross-sectional view showing the second press working process in the above molding method. [Modes for carrying out the invention]

[0011] A method for forming the toe control arm mounting portion according to the embodiment will be described with reference to the drawings.

[0012] First, with reference to Figure 1, the state in which the toe control arm 1 is attached to the toe control arm mounting portion formed according to this embodiment will be described. Note that Figure 1 shows the mounting portion in a simplified manner. The toe control arm 1 is one of the suspension components of the vehicle. Also, Figure 1 shows the state in which it is attached to the vehicle body, and is a bottom view relative to the vehicle body. That is, in this embodiment, the bolts 4 are arranged horizontally. However, the construction of the mounting portion on the vehicle body is not limited to this. The mounting portion may be constructed so that the bolts 4 are arranged vertically, or the mounting portion may be constructed with the bolts 4 inclined relative to the horizontal and vertical.

[0013] As shown in Figure 1, a metal cylindrical portion 1A is formed at one end of a metal toe control arm 1, and an annular bush 2 is press-fitted into the interior of this cylindrical portion 1A. In this embodiment, the bush 2 is a rubber bush, but other types of bushes such as ball bushes may also be used. The mounting portion of the toe control arm 1, i.e., the mounting portion of the bush 2, is a bracket 3 formed from a pressed steel plate part.

[0014] Bracket 3 comprises a pair of bracket plates 3A spaced apart in the direction of the central axis X of bush 2, with bolt insertion holes 3B formed in each bracket plate 3A. Each bracket plate 3A also has a flange 3C that is welded to the vehicle body. Bushing 2 is sandwiched between this pair of bracket plates 3A and attached to bracket 3 by bolts 4 and nuts 5. At this time, circular eccentric cam plates 6 are also fastened together with each of the bracket plates 3A.

[0015] The bolt 4 is inserted in the following order: one eccentric cam plate 6, one bracket plate 3A, the collar 2A of the bush 2, the other bracket plate 3A, and the other eccentric cam plate 6, and a nut 5 is screwed onto its end. Although not shown in the figure, washers may be interposed between the head of the bolt 4 and the nut 5 and the eccentric cam plate 6. Alternatively, flanges may be formed on the head of the bolt 4 and the nut 5.

[0016] The bolt holes 6A of the eccentric cam plate 6 are eccentric with respect to the center of the circle. By changing the rotational position of the pair of eccentric cam plates 6, the position of the bush 2 relative to the bracket 3 can be adjusted. Therefore, by changing the rotational position of the pair of eccentric cam plates 6, the suspension geometry can be adjusted. In order to match the rotational positions of both the pair of eccentric cam plates 6 with respect to the bolt 4, a key (not shown) protrudes from the bolt hole 6A of the eccentric cam plate 6 toward the center of the hole. On the other hand, a slot (not shown) that engages with this key is formed on the outer circumference of the bolt 4 along the direction of the central axis X.

[0017] Here, the rotational position of the eccentric cam plate 6 can be changed relative to the bracket plate 3A, but the mounting position of the eccentric cam plate 6 on the bracket plate is fixed. That is, the mounting position of the eccentric cam plate 6 relative to the bracket plate 3A is restricted to a predetermined position. For this reason, a pair of opposing stoppers 3D are provided on the bracket plate 3A. The eccentric cam plate 6 is mounted in a predetermined position on the bracket plate 3A by being fitted between the pair of opposing stoppers 3D. More specifically, if the mounting position of the eccentric cam plate 6 attempts to shift, its peripheral edge will come into contact with the vertical wall 3V of the stopper 3D, so the mounting position of the eccentric cam plate 6 is restricted by the vertical wall 3V.

[0018] As described above, the position of the bolt 4 with respect to the bracket plate 3A, that is, the position of the bush 2, can be adjusted according to the rotational position of the eccentric cam plate 6. Therefore, in order to allow for this change in the position of the bolt 4, the bolt insertion hole 3B of the bracket plate 3A is elongated or increased in diameter with respect to the outer diameter of the bolt 4. Also, due to the above configuration, the bolt insertion hole 3B of the bracket plate 3A is disposed between the pair of stoppers 3D.

[0019] Next, a method for forming the attachment portion having the above-described configuration, more specifically, a method for forming the stopper 3D on the metal plate 3X that becomes the bracket plate 3A, will be described with reference to FIGS. 2 to 4. The pair of stoppers 3D are formed simultaneously by the pressing process of the metal plate 3X. Hereinafter, one of them will be described as an example.

[0020] In the present embodiment, first, as shown in FIG. 2, a flat metal plate 3X is sandwiched between a pair of molds and pre-pressed to form a bulged portion 3E that finally becomes the stopper 3D on the metal plate 3X. Although not shown, at this time, a convex portion is formed on one of the molds, and a concave portion corresponding to this convex portion is formed on the other mold. By being sandwiched between these convex and concave portions, the bulged portion 3E is formed. The bulged portion 3E is formed in a form that gently bulges and is substantially circular in plan view. The height of the bulged portion 3E with respect to the surface of the metal plate 3X is, for example, 8 mm.

[0021] Next, as shown in FIG. 3, a first press process is performed on the metal plate 3X so that the stopper 3D protrudes without causing a cut on the surface of the metal plate 3X. In the present embodiment, since the above-described pre-pressing process has been performed, more specifically, the bulged portion 3E is reshaped and protruded as the stopper 3D. Note that the stopper 3D shown in FIG. 3 may be formed only by this first press process without performing the pre-pressing process. However, in this case, the shape of D1 is different, and D1 has a convex portion for forming the stopper 3D.

[0022] In this embodiment, a mold D1 is arranged on one side of a metal plate 3X, and molds D2 and D3 are arranged on the other side of the metal plate 3X. A stopper 3D is formed by these three molds D1 to D3. In this embodiment, first, after the metal plate 3X is sandwiched by the molds D1 and D2, molding with the mold D3 is performed. A bulging portion 3E is partially crushed by the molds D1 and D2 to form a vertical wall 3V, and the remaining portion is crushed by the molds D1 and D3 to form an inclined protrusion with a reference inclination of 30 degrees.

[0023] As a result, on the stopper 3D, a vertical wall 3V that restricts the peripheral portion of the eccentric cam plate 6 is formed by the side surface of the mold D2. At this time, the bulging portion 3E is pressed against the side surface of the mold D2 by the inclined surface of the mold D3 to form the vertical wall 3V. The surface of the vertical wall 3V is flat. However, the stopper 3D at this time is not in the final form and is formed into the final form by the second press working described below. The height of the inclined surface of the mold D3 during the first press working is, for example, 6 mm. Therefore, the height of the stopper 3D after the first press working is, for example, approximately 6 mm.

[0024] Finally, as shown in FIG. 4, the second press working is performed on the metal plate 3X to crush the vertical wall 3V formed by the first press working, thereby increasing the thickness of the vertical wall 3V. At this time, a mold D1 is arranged on one side of the metal plate 3X, and molds D4 and D5 are arranged on the other side of the metal plate 3X. The stopper 3D is formed into the final form by these three molds D1, D4, and D5. Here too, first, after the metal plate 3X is sandwiched by the molds D1 and D4, molding with the molds D1 and D5 is performed. The stopper 3D formed by the first press working, particularly its vertical wall 3V, is crushed by the molds D1 and D5. In order to crush the vertical wall 3V in its vertical direction, the mold D5 has a surface perpendicular to this vertical direction. This vertical direction is also the mold clamping direction.

[0025] As a result, the vertical wall 3V is crushed in its vertical direction, increasing its thickness, i.e., it is thickened. At the same time, the crushing of the vertical wall 3V in its vertical direction ensures that the material of the metal plate 3X is sufficiently filled up to the cross-sectional corner of the upper edge of the vertical wall 3V. Furthermore, the cross-sectional corner at the base end of the vertical wall 3V is processed by two press workings to reduce its radius of curvature R1. The die D5 is configured to allow further deformation of the stopper 3D formed in the first press working, by creating a gap G that does not come into contact with the inclined wall 3S of the stopper 3D. In this embodiment, the thickness of the inclined wall 3S is also increased at this time. The height of the stopper 3D relative to the surface of the metal plate 3X after the second press working is, for example, 4 mm. The radius of curvature R1 of the cross-sectional corner at the base end of the vertical wall 3V is, for example, 1 mm.

[0026] The final form of the stopper 3D is similar to one half of a frustum of a perfect cone or frustum of an ellipse that has been cut in half along a cross-section that includes its central axis. This form of stopper 3D is formed integrally with the metal plate 3X. In a pair of stoppers 3D formed on the metal plate 3X (bracket plate 3A), the vertical walls 3V face each other, and their surfaces are parallel to each other.

[0027] According to the method for forming the toe control arm mounting portion of the above embodiment, first, a first press is performed on the metal plate 3X which will become the bracket plate 3A. The first press causes the stopper 3D to protrude from the surface of the metal plate 3X without creating a cut. At this time, a vertical wall 3V that restricts the peripheral edge of the eccentric cam plate 6 is formed on the stopper 3D. Next, a second press is performed on the metal plate 3X, and the thickness of the vertical wall 3V formed in the first press is increased by crushing it.

[0028] Therefore, according to the above forming method, a stopper having a reinforced vertical wall 3V can be formed by at least two press operations without creating cuts in the metal plate 3X (bracket plate 3A). Since the stopper 3D is formed without creating cuts in the metal plate 3X (bracket plate 3A), even if a large load is applied to the bracket plate 3A via the toe control arm 1, the bracket 3 can be prevented from cracking or deforming. Furthermore, although this load is applied to the vertical wall 3V via the eccentric cam plate 6, the stopper 3D can withstand this load more reliably because the vertical wall 3V is reinforced.

[0029] Furthermore, since the vertical wall 3V is formed and thickened by at least two press processes, the radius of curvature R1 of the cross-sectional corner at the base end of the vertical wall 3V can be reduced. Therefore, it is possible to avoid the eccentric cam plate 6 riding up onto the cross-sectional corner and to ensure that the eccentric cam plate 6 makes firm surface contact with the bracket plate 3A. As a result, the toe control arm 1 can be securely attached to the bracket 3, which is its mounting part.

[0030] Furthermore, Figure 1 of the aforementioned Patent Document 1 discloses an embodiment different from that of Figure 4, in which a regulating member corresponding to the pair of stoppers 3D in the above embodiment is prepared separately and welded to the bracket. However, with such a configuration, a regulating member must be prepared separately from the bracket, which increases the number of parts and the weight. Also, welding must be performed, which increases the number of processes. These lead to increased costs. According to the above embodiment, these problems can be avoided.

[0031] In the forming method according to the above embodiment, prior to the first press working, a preliminary press working is performed on the metal sheet 3X to create a stopper 3D (bulge 3E) on the surface of the metal sheet 3X. In the subsequent first press working, a vertical wall 3V is formed on the stopper 3D (bulge 3E) that was bulged in the preliminary press working. Although this preliminary press working adds one more pressing step, it allows for the stable formation of the shape of the stopper 3D. In the preliminary press working, the metal sheet 3X is stretched (drawn), but in the first and second press working, the metal sheet 3X is crushed (compressed). Since the stopper 3D, i.e., the vertical wall 3V, is formed in these first and second press working, the shape of the vertical wall 3V is stable, and it also becomes easier to increase the thickness of the vertical wall 3V.

[0032] In the forming method according to the above embodiment, the second press working process increases the thickness of the vertical wall 3V by crushing it, and also fills the cross-sectional corners of the upper edge of the vertical wall 3V with the material of the metal plate 3X. This stabilizes the shape of the vertical wall 3V and improves the workability when assembling the eccentric cam plate 6 between the pair of stoppers 3D. When assembling the eccentric cam plate 6 to the bracket 3, it becomes easier to fit the eccentric cam plate 6 between the pair of stoppers 3D, and it is also easier to clearly recognize that it has been securely fitted, thus improving workability.

[0033] As described above, embodiments of the present invention have been presented, but the statements and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure. [Explanation of symbols]

[0034] 1. Toe control arm 3 brackets 3A Bracket Plate 3D Stopper 3E Bulging section (pre-molding of stopper 3D) 3V vertical wall 3X metal plate 4 bolts 5 nuts 6. Eccentric cam plate

Claims

1. A method for forming the mounting portion of a vehicle's toe control arm, The mounting portion comprises a bracket having a pair of bracket plates that clamp a bush provided at one end of the toe control arm, and a circular eccentric cam plate that is attached to each of the pair of bracket plates together with the bush using bolts and nuts. Each of the pair of bracket plates is formed with a pair of stoppers that restrict the mounting position of the eccentric cam plate relative to the bracket plate. In the aforementioned molding method, A first press is performed on the metal plates that will form the pair of bracket plates, so that each of the pair of stoppers protrudes from the surface of the metal plate without creating a cut, and a vertical wall is formed on the stopper that restricts the peripheral edge of the eccentric cam plate. A method for forming a toe control arm mounting portion, comprising performing a second press operation on the metal plate to crush the vertical wall formed in the first press operation, thereby increasing the thickness of the vertical wall.

2. A method for forming a toe control arm mounting portion according to claim 1, Prior to the first press working, a preliminary press working is performed on the metal plate to pre-form each of the pair of stoppers so that they bulge out on the surface of the metal plate. A method for forming a toe control arm mounting portion, wherein the first pressing process involves forming the vertical wall against the stopper that was bulged in the preliminary pressing process.

3. A method for forming a toe control arm mounting portion according to claim 1 or 2, A method for forming a toe control arm mounting portion, wherein in the second pressing process, the thickness of the vertical wall is increased by crushing the vertical wall, and the metal plate material is filled up to the cross-sectional corner of the upper edge of the vertical wall.

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