JP2005082140A - Forged suspension member and suspension arm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forged suspension member allowing compact formation of a joint part by securing strength for the dimension of the joint part and largely taking of the length of an arm part, a forged suspension member allowing proper forging, even if the arrangement of a parting line is changed, and a suspension arm. <P>SOLUTION: The forged suspension member 1f is provided with the arm part 6f, the joint part 2f, a vehicle body side engaging part and a parting line P1 formed at a prescribed position. The joint part 2f is provided with one end face part 3f, the other end face part 4f and a side surface part 5f. A position h of the parting line P1 in the side surface part 5f of the joint part 2f to be a farthest position from the arm part 6f is provided within the range of a ratio shown by 0.4>h≥0.2W from the one end face part or the other end face part when a thickness dimension from the one end face part to the other end face part is made as W. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a suspension arm that is used as a suspension member disposed around a wheel of an automobile or the like and is attached via a stud bolt that becomes an engagement structure, and a forged suspension for machining and forming the suspension arm. This relates to the member.

  In general, a suspension member for an automobile such as a suspension arm attached to a support member such as a knuckle or a carrier supported by an axle of an automobile or the like via a joint structure joined to a ball stud bolt has a predetermined length. An arm portion provided, a ball joint portion supported by the ball stud bolt on one end side of the arm portion, a vehicle body side engaging portion engaged with a vehicle body side such as a sub member on the other end side of the arm portion, Various things have been proposed, such as those equipped with.

  For example, as a suspension arm, in order to improve steering stability, the distance between the fulcrum points from one ball joint part to the other ball joint part (vehicle body side engaging part) can be increased. It is known that the scrub radius (distance between intersections of the line connecting the center line of the wheel and the upper and lower joints on the tire contact surface) can be reduced and the torque steer can be reduced by bringing the joint center of the portion closer to the tire center. Therefore, it is desired to form the ball joint portion in the suspension arm so as to reduce the size.

  Further, since the installation environment in which the suspension arm is installed is in the vicinity of the wheel of the automobile, the installation space is limited, and there is a restriction in the case of the suspension arm that realizes the configuration of the arm portion described above. Therefore, it is desired to increase the degree of design freedom by reducing the shape of the ball joint portion in the suspension arm.

  On the other hand, the suspension arm is made of steel, and the structure including the steel ball joint portion is formed by press molding, so the ball joint portion tends to be large (for example, Patent Document 1). Therefore, conventionally, instead of steel material, the suspension arm is made of aluminum alloy, the ball joint part and the arm part are integrated, the ball joint part is small, the arm part is formed long, the strength and The thing superior to steel from the point of weight is proposed (for example, patent document 2).

  Further, as shown in FIG. 9A, the suspension arm formed of an aluminum alloy is formed by forging the ball joint portion 102 integrally with the arm portion 106, and then the ball portion 134 of the ball stud bolt 133 is formed. An insertion hole for insertion is processed, and the ball stud bolt 133 is configured to be inserted and assembled in a state of interposing an interposition member 138 composed of a plurality of parts.

  When the suspension arm 100 is forged, a parting line PL is formed in the arm part 106 and the ball joint part 102, and the parting line PL is arranged at a substantially central position of the ball joint part 102. The side part 105 is formed so that the center protrudes.

  The arm portion and the ball joint portion are each forged with a machining allowance and with a draft angle. In addition, the suspension arm is applied with a force in the direction in which the ball stud bolt enters and exits during traveling of the automobile, for example, so that a large stress is applied to the suspension arm. A certain volume of material must be secured. Further, the state of the grain flow GF when the parting line PL is formed at the center position of the suspension arm 100 is schematically shown in FIG.

  JP-A-10-37944 (paragraph numbers 0013 to 0017)   JP 2000-355206 A (paragraph numbers 0010 to 0015)

However, the configuration of a suspension arm formed of a conventional aluminum alloy has the following problems.
In the conventional suspension arm configuration, the grain flow is concentrated and the parting line, which is the weakest in strength, is located at the center of the ball joint in the thickness direction. There was a limit.

  Further, in the conventional suspension arm, the parting line is arranged at the center in the thickness direction on the side surfaces of the ball joint portion and the arm portion, so the variation margin of the remaining burr length caused by forging trimming is the center in the thickness direction. It is necessary to increase the thickness against the draft angle, and in addition to this increased thickness, it is necessary to add a dimension to ensure the range of interference with the wheel when joined to a support member such as a carrier supported by the axle. was there. For this reason, the suspension arm is restricted from bringing the ball joint portion closer to the wheel, and the degree of freedom in design is hindered.

Furthermore, in the suspension arm, in order to make the ball stud bolt compact, the draft angle of the side surface portion is made zero or minimum by inclining the ball joint portion and providing a parting line at the peripheral edge of either end surface. Is possible. However, when the parting line is provided on the caulking side end surface, the grain flow concentrates on the caulking portion to be caulked, and the pushing load direction of the caulking portion and the grain flow are orthogonal to each other. The strength in the T direction results in a decrease in punching strength.
Similarly, when the parting line is provided along the peripheral edge of the stud bolt side end surface, the drawing load direction and the grain flow of the portion deformed by the drawing load are orthogonal to each other, so that the drawing strength is reduced. Therefore, there has been a demand for a forged suspension member that is effective for grain flow.

  The present invention has been devised in view of the above-described problems, and can be formed compactly while ensuring strength with respect to the dimensions of the ball joint portion, and can be provided with a large arm portion length. An object of the present invention is to provide a forged suspension member and a suspension arm that can perform appropriate forging even if the arrangement of the ring line changes, and that are also effective for grain flow.

  In order to achieve the above object, the present invention has the following configuration. That is, the forged suspension member according to the present invention is a ball joint part that is attached to a support member supported on the axle side of an automobile via a stud bolt so as to be rotatable and avoid an interference area with axle side parts. A forged suspension member for forming a suspension arm having an arm by machining, wherein the forged suspension member includes an arm portion, a ball joint portion provided at one end of the arm portion, and a vehicle body provided at the other end of the arm portion. A side engaging portion, and a parting line formed continuously at predetermined positions of the arm portion, the ball joint portion, and the vehicle body side engaging portion, and the ball joint portion includes one end surface portion, It is formed across the other end surface portion facing the one end surface portion, the other end surface portion and the one end surface portion. A position h of the parting line in the side surface portion of the ball joint portion which is the farthest position from the arm portion when the thickness dimension from the one end surface portion to the other end surface portion is W, From the one end surface portion or from the other end surface portion, it is provided within a range of a ratio represented by 0.4 W> h ≧ 0.2 W. In addition, you may be the structure which inclines a predetermined angle in the said arm part and provides a ball joint part (Claim 2).

  By being configured in this manner, the forged suspension member has 0.4 W> h ≧ 0 in the side surface portion where the concentration of grain flow due to the parting line position is farthest from the arm portion in the ball joint portion during forging. The ball stud bolt's pull-out strength and pushing force are higher than when the parting line is along the periphery of both end faces when machined into a suspension arm because it is formed toward a position within the range of 2 W. The drawing strength can be improved. In addition, the parting line at the ball joint part is shifted from the center to one end face side or the other end face side, so the thickened part required for draft is compared with the parting line in the center And less. Furthermore, the degree to which the grain flow at the caulking part is parallel to the shearing direction during caulking is reduced. The forging suspension member is forged with the forging posture set in a direction in which the parting line of the arm portion is orthogonal to the forging press direction in the configuration in which the ball joint portion is provided at a predetermined angle with respect to the arm portion. In addition, when the ball joint portion is provided without being inclined with respect to the arm portion, the parting line of the arm portion is forged by a predetermined angle with respect to the forging press direction.

  Further, in the forged suspension member, the parting line of the ball joint part is formed so as to connect the position h in a straight line continuously from the position of the parting line of the arm part, The parting line of the ball joint part is formed so as to incline in a curved line or a straight line from the position of the parting line of the arm part so as to connect the position h, or the ball The parting line of the joint part is formed to extend to the center of the ball joint part in the state of the parting line of the arm part, and is formed so as to connect the position h from the center of the ball joint part. It is also possible to adopt a configuration (claims 3 to 5).

  By being configured in this way, the forged suspension member maintains a state in which the stud bolt pull-out load is improved in the concentration of grain flow at the parting line position, and the parting that matches the configuration on the wheel side of the automobile The type of line can be selected and used, and the parting line can be set corresponding to the form of the ball joint portion in the forged suspension member.

Further, in the forged suspension member, the parting line of the ball joint portion is formed in a peripheral line shape of a predetermined dimension along the peripheral edge of the one end surface part or the other end surface part at the position h, and the peripheral line shape It is configured to be formed continuously from the both end positions to the parting line of the arm.
By configuring in this way, the forged suspension member has a position in the interference region when the draft is provided so as to incline toward the one end surface portion and the other end surface portion with the parting line in the ball joint portion as a boundary. The amount of additional meat accompanying the grinding line can be reduced.

The forged suspension member is configured to be disposed at a position where the parting line of the ball joint portion located in the interference region is removed by machining (Claim 7).
By being configured in this manner, the forged suspension member can remove the protruding portion due to the parting line in the interference region when machined.

Furthermore, in a suspension arm formed by machining the forged suspension member, a radius of a ball ball diameter of a stud bolt engaged with the ball joint portion of the suspension arm is R1, and the ball is bent from the center of the ball joint portion. When the distance to the outermost part in the interference area of the joint portion is the distance R2, the ball joint portion is formed at a ratio represented by 1.2 <R1 / R2 ≦ 1.9 (Claim 8).
With this configuration, the suspension arm can maintain the degree of freedom in designing the ball joint portion and can maintain the strength of the ball joint portion.

In the suspension arm, the pull-out strength or the punch-out strength of the stud bolt is 25 kN or more.
In the suspension arm configured as described above, even when the ball stud bolt moves up and down due to the bounce of the wheel during traveling of the vehicle, the suspension arm does not come off the ball joint portion.

Further, in the suspension arm, the forged suspension member is made of an Al—Mg—Si based aluminum alloy having an average area ratio of sub-crystal grains in the structure of 60% or more and a 0.2% proof stress of 290 MPa or more. (Claim 10)
Further, the suspension arm configured as described above is made of a high-strength aluminum alloy, and the wall thickness can be reduced while maintaining the holding force of the ball portion of the ball joint portion.

The forged suspension member according to the present invention has the following excellent effects.
The forged suspension member has a parting line position h at the time of forging in the side surface portion of the ball joint portion which is the farthest position from the arm portion, when the thickness dimension from the one end surface portion to the other end surface portion is W, Since it is provided within the range of 0.4 W> h ≧ 0.2 W, when the ball stud bolt is engaged by caulking, the degree to which the grain flow is parallel to the shearing direction of caulking is reduced. No problems such as cracking occur during caulking. Therefore, in the state of being commercialized through machining, the grain flow in the vicinity of both end surface portions is compared to that of the parting line formed along either peripheral side of the both end surface portions of the ball joint portion. The degree of orthogonality to the direction of the punching and pulling load is reduced, and an improvement in the pulling and pushing load of the stud bolt can be expected.

  Therefore, the forged suspension member and the suspension arm can be reduced in size, the joint center of the ball joint portion can be brought closer to the tire center, the degree of freedom of design can be expanded, and the scrub radius can be reduced. Can provide. Further, the forged suspension member requires less increase in the thickness required for the parting draft in the ball joint portion than the one having a parting line in the center, and is excellent economically.

  Further, the forged suspension member maintains the improvement of the pull-out load of the stud bolt and can also select the type of the parting line as compared with the configuration of the parting line provided along one peripheral edge of the both end faces. Therefore, it is possible to select and use the parting line type that matches the configuration of the vehicle wheel side.

  Furthermore, the forged suspension member is advantageous for caulking, because it is arranged in a range where the parting line is machined and removed in the range that becomes the interference region, and further, the strength is maintained and the interference region is maintained. Miniaturization can be achieved without protruding.

  When the suspension arm formed by machining from the forged suspension member has a distance of the ball diameter of the stud bolt as R1, and a distance from the center of the ball joint portion to the outermost diameter in the interference region as a distance R2, Since the ratio is configured to satisfy 1.2 <R2 / R1 ≦ 1.9, it is possible to reduce the size by balancing the degree of freedom in designing the ball joint portion and the strength of the ball joint portion.

  The suspension arm can be made slim by using a high-strength aluminum material or by satisfying the conditions for the pulling strength and the punching strength.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view in which a part of the suspension arm mounting position is omitted, FIG. 2 is a side view of a state in which a part of the suspension arm is broken, and FIG. 3A is a ball joint portion of the suspension arm. FIG. 4B is a perspective view schematically showing a state before the machining of the ball joint portion of the suspension arm, and FIGS. 4A and 4B are one end surface portions of the ball joint portion of the suspension arm. FIG. 5 is a side view schematically illustrating the grain flow in the ball joint portion of the suspension arm, and FIG. (a), (b) is a top view which each shows typically two types of suspension arms as an example, respectively. In each figure, the reference numeral indicating the forged suspension member will be described by adding “f” to the reference numeral attached to the suspension arm.

  As shown in FIGS. 1 and 5, the suspension arm 1 includes an arm portion 6, a ball joint portion 2 formed at one end of the arm portion 6, and a vehicle body side engagement formed at the other end of the arm portion 6. And a joint section 9. The suspension arm 1 is forged with an aluminum alloy or the like and then machined from a forged suspension member 1f (see FIG. 3), and is a support member (knuckle, carrier that constitutes the suspension of the axle 31 of the wheel 30). The ball joint portion 2 is rotatably supported with respect to the interference region IF through 32 ball stud bolts (stud bolts) 33, and the vehicle body side engaging portion 9 is connected to the vehicle body side of the axle 31 (not shown). 2) is engaged and supported at the engaging position. As shown in FIG. 4, the interference area IF is described as a range of 100 degrees from the center of the ball joint portion 2f (2) as an example here, but is not limited to this range.

  As shown in FIG. 2, the ball stud bolt 33 interposed between the support member 32 (see FIG. 1) and the suspension arm 1 includes a screw portion 35 fixed by a nut to engage the support member 32, A barrel portion 36 continuing from the screw portion 35 and a ball portion 34 provided at an end portion of the barrel portion 36 are provided. When the ball stud bolt 33 is supported by the ball joint portion 2, the ball portion 34 can be freely rotated in a 360 degree direction with respect to the stud bolt neutral direction (direction perpendicular to the one end surface portion 3) SN. As described above, the ball joint portion 2 is supported by being engaged via an interposed member 38 (in this case, indicated as one component) (or directly without using the interposed member 38).

  As shown in FIGS. 6 (a) and 6 (b), the suspension arm 1 has a complex shape that is non-axisymmetric with respect to the wheel, such as one having two vehicle body side engaging portions 9 or only one. In many cases, it has the same strength and corrosion resistance as iron materials, and therefore, A6061 and its derivatives 6000 series, and aluminum alloys such as high-strength aluminum alloy materials are used. An example of the high-strength aluminum alloy material is an Al—Mg—Si based aluminum alloy having an average area ratio of sub-crystal grains in the structure of 60% or more and a 0.2% proof stress of 290 MPa or more.

  In aluminum alloys, the proportion of sub-crystal grains in the forged material structure has a greater effect on the strength, toughness and corrosion resistance of the forged material than the refinement of the crystal grains in the forged material structure (contribution). To do. That is, by increasing the ratio of the sub-crystal grains in the forged material structure, it is possible to achieve high strength, high toughness and high corrosion resistance of the forged material with good reproducibility. In other words, even if the average crystal grain size of the forged material structure is refined to 50 to 80 μm by high-temperature forging, the average area ratio of sub-crystal grains finer than the crystal grain size should be small in the forged material structure. Therefore, it is impossible to achieve high strength, high toughness, and high corrosion resistance of the forged material with good reproducibility.

  Therefore, if the average area ratio of the sub-crystal grains in the forged material structure is 60% or more, the 0.2% proof stress of the forged material can be 290 MPa or more, and the stress corrosion cracking resistance can be improved. Further, when the average area ratio of the sub-crystal grains is preferably 90% or more, the 0.2% proof stress of the forged material can be increased from 350 MPa or more, along with the stress corrosion cracking resistance.

  The measurement of sub-crystal grains of this high-strength aluminum alloy material is performed by electrolytically etching the microstructure measurement cross section of the forged material, in particular, by clarifying the sub-crystal grain boundaries and the crystal grain boundaries, This is done after discriminating between the boundaries and sub-crystal grains. At this time, in order to take into account variations due to the forged material parts, it is performed by observing 20 fields of view where the positions of measurement (data collection) are changed at the parts where the strength and corrosion resistance of each forged material are required. Then, the average area ratio of the sub-crystal grains is measured by visual processing or image processing for the area occupied by the sub-crystal grains for each visual field, and the area ratio of the sub-crystal grains relative to the one visual field area is calculated, The area ratio of the sub-crystal grains in 20 fields is averaged to obtain the average area ratio (%) of the sub-crystal grains.

  A forged suspension member 1f for forming the suspension arm 1 by machining is forged by a forging die (not shown) including an upper die and a lower die. FIG. 2 shows that the stud bolt neutral direction SN of the ball stud bolt 33 is in a state of being perpendicular to the plane of the arm portion 6. A forging die (not shown) is configured to be a mold split surface at predetermined positions of the arm portion 6f, the ball joint portion 2f, and the vehicle body side engaging portion.

  As shown in FIGS. 3A and 3B, the parting line P2 of the arm portion 6f at the time of forging is disposed at the center position in the thickness direction E on the side surface of the arm portion 6f. However, it may be formed at any position on the side surface from the upper end side to the lower end side.

Further, as shown in FIGS. 3A and 3B, the parting line P1 of the ball joint portion 2f during forging is the position of the side surface portion 5f farthest from the arm portion 6 (the tip of the ball joint portion 2f). When the position h of the parting line P1 at the position or the end of the ball joint portion of the forging die is the thickness dimension W from the one end surface portion 3f to the other end surface portion 4f, the one end surface portion 3f or the other end surface portion 4f. To 0.4 W> h ≧ 0.2 W. The parting line P1 of the ball joint part 2f is provided so as to be continuous with the parting line P2 of the arm part 6f.
Here, the parting line PL is a parting line P2 formed in a horizontal straight line shape of the arm portion 6f, and a parting line formed in a horizontal straight line shape, an inclined line shape, and a horizontal straight line shape of the ball joint portion 2f. It is comprised by the line P1. As shown in FIGS. 3A and 3B, the parting line P1 of the ball joint portion 2f has a thickness dimension W from the one end surface portion 3f to the other end surface portion 4f. A horizontal straight line parallel to the one end face 3f at a position of approximately h = 0.2 W is formed in an inclined line shape toward the center of the ball joint part 2f, and then the same height as the parting line P2 of the arm part. It arrange | positions here so that it may continue in a position. In addition, the position h of the parting line P1 in the side surface part f of the ball joint part 2f corresponds to an inclined surface that becomes a draft when being forged. For this reason, in the side surface portion 5f in the interference region of the forged suspension member 2f, there is no protrusion or the minimum at the portion farthest from the arm portion 6f.
In the ball joint part 2f, the parting line P1 may be continuously formed from the parting line P2 of the arm part 6f toward the point of the position h with the position h as a point.

  The reason why the position h of the parting line P1 at the tip position of the ball joint portion 2f is 0.4 W> h from the one end surface portion 3f or the other end surface portion 4f will be described below. That is, as shown in FIG. 5, when the parting line P1 is arranged so that 0.4 W ≦ h with respect to the center in the thickness direction of the ball joint portion 2f, the range in which the draft is provided is increased, and the compactness is achieved. It is disadvantageous.

  The reason why the position h of the parting line P1 at the tip position of the ball joint portion 2f is 0.2W ≦ h from the one end surface portion 3f or the other end surface portion 4f is as follows. That is, in the state of 0.2 W> h that is out of the range, the parting line P1 in the ball joint portion 2f is too close to the portion to be caulked during machining, and forging is performed on any of the end surface portions 3f and 4f. As a result, the grain flow GF generated due to the above will come out strongly in the ST direction (the direction perpendicular to the parting line P1), leading to a decrease in the pullout strength (punch strength).

  Therefore, in the state of 0.2 W> h where the position h of the parting line P1 is out of the range at the tip position of the ball joint portion 2f, if caulking is performed, a shearing force acts on the tissue of the grain flow GF. Will do. This is because the metal structure in the ball joint portion 2f is very strong against the force in the direction parallel to the grain flow GF, but from a direction perpendicular to or substantially perpendicular to the grain flow GF (see FIG. 5). The force is very weak, and when the grain flow GF (see FIG. 5) is concentrated, the force tends to become weaker against the shearing force. Therefore, in the case where a step of applying a force such as caulking is applied to the ball joint portion 2f, cracking may occur if the caulking is performed at a position of 0.2 W> h that is outside the range.

  When the position h of the parting line P1 is h ≧ 0.2 W at the tip position of the ball joint portion 2f, the grain flow GF does not concentrate on the crimped portion as shown in FIG. Therefore, even if the ball joint portion 2 is subjected to a caulking process or the like, no crack is generated.

  Further, in the ball joint portion 2f, the position h of the parting line P1 in the side surface portion 5f that is the farthest position from the arm portion 6f is, for example, left and right from the position of the side surface portion that is the farthest position from the arm portion 6f. In the region of 50 degrees), after forging, it is convenient to arrange in a range that can be removed by machining. That is, the position h is 0.4 W> h ≧ 0.2 W, and in the interference region, the grain flow GF is shifted from the center as shown in FIG. Thus, it is possible to improve the strength of the ball joint portion 2f and to remove the protrusion in the interference region.

  When the parting line P1 of the ball joint part 2f is machined and formed on the suspension arm 1, the parting line P1 is parted by extrapolating an extension line from the grain flow GF of the part that has not been cut by machining. The position of the line PL (P1) can be specified. If there is a forging die, the parting line P1 in the ball joint portion 2f can be specified based on the forging die.

  Further, as shown in FIGS. 4A and 4B, a curve surrounding an axial cross section along the parting line P1 formed in the ball joint portion 2f when projected onto a plane orthogonal to the forging press direction T. The region S is set to be maximum with respect to the region S1 in the one end surface portion 3f and the region S2 in the other end surface portion 4f of the ball joint portion 2f projected onto the plane orthogonal to the forging press direction T. In FIG. 4, the forging press direction T is assumed to be a direction orthogonal to the parting line PL. However, the forging press direction T has various directions.

  As described above, the reason for maximizing the curved region S surrounding the axial cross section along the parting line P1 formed in the ball joint portion 2f when projected onto the plane orthogonal to the forging press direction T is forging. This is to ensure that a draft angle is sometimes secured. Therefore, regardless of whether the position h of the parting line P1 is set within the range of 0.4W> h ≧ 0.2W at the tip position of the ball joint portion 2, the region S under the above-described conditions is the regions S1, S2. It is set to be the maximum compared to.

  Further, as shown in FIGS. 3A and 3B, in the ball joint portion 2f, in the design stage, the arrangement of the parting line P1 is specified, and the planar shapes of the one end surface portion 3f and the other end surface portion 4f are specified. The The ball joint portion 2f has a perfect circle when the sectional shape at the position along the parting line P1 is viewed from the stud bolt neutral direction (direction perpendicular to the plane of the one end surface portion 3) SN (see FIG. 2). Alternatively, it is formed to be an approximate perfect circle. The planar shape of the one end surface portion 3f of the ball joint portion 2f is assumed to be a virtual cone with a draft (inclination of the side surface portion 5f) with respect to the forging press direction with the cross-sectional shape along the parting line P1 as the bottom surface. The virtual cone is formed in a shape that is set in a plane that is cut at the planar position of the one end surface portion 3f and a range condition that does not protrude from the virtual cone.

  Similarly, the planar shape of the other end surface portion 4f is the other end surface portion 4f in the hypothetical cone when a cone with a draft (inclination of the side surface portion 5) is assumed with the cross-sectional shape along the parting line P1 as the bottom surface. And a shape set in a range condition that does not protrude from the virtual cone. Therefore, the side surface portion 5f of the ball joint portion 2f has a shape inclined in opposite directions with respect to the parting line PL (P1).

  Further, as shown in FIG. 3A, the ball joint portion 2f is parted in the center of the conventional case when machining is performed so that the ball stud bolt 33 (see FIG. 2) can be engaged and supported. Compared with a ball joint portion with a line, by shifting from the center and using the side surface portion 5f as an inclined surface with a draft, the addition of sacrificial meat accompanying the slope angle is reduced or not at all. Therefore, the joint center can be made closer to the wheel center for the size of the ball joint portion 2 that is reduced. In addition, when setting it as the structure which lengthens the arm part 6, the reinforcement | strengthening with respect to the part which lengthened the arm part 6 is needed.

  As shown in FIG. 3A, the forged suspension member 1f is machined as indicated by a solid line inside the imaginary line, and is formed as an example in the state of the suspension arm 1 as shown in FIG. In the ball joint portion 2 of the suspension arm 1, the opening portion 4 a of the other end surface portion 4 penetrates from the opening portion 3 a of the one end surface portion 3, and the ball portion 34 of the ball stud bolt 33 is inserted into a plurality of parts. It is formed so that it can be engaged and supported via the interposition member 38. Further, the ball joint portion 2 is configured such that a step portion is formed slightly above the center of the side surface portion 5 to form a locking portion 5b, and a dust cover 37 is engaged with the locking portion 5b. .

  As shown in FIG. 2, the suspension arm 1 has a radius R1 of the ball diameter of the ball portion 34 of the ball stud bolt 33 and a distance from the center position of the ball portion 34 of the ball joint portion 2 to the outermost portion. The ball joint portion 2 is formed within a range where R2 is a ratio represented by 1.2 <R2 / R1 ≦ 1.9.

  This R2 / R1 is related to the degree of freedom and strength of design of the ball joint portion 2. When R2 / R1 is reduced, the degree of freedom of design increases, but the strength of the ball joint portion 2 becomes insufficient. If it is .2 or less, the required strength cannot be obtained reliably. Further, when R2 / R1 is increased, the strength of the ball joint portion 2 is increased, but the degree of freedom of design is narrowed. In particular, when it exceeds 1.9, the necessary degree of freedom is surely inhibited.

  And the drawing strength and the punching strength in the ball joint portion 2 configured as 1.2 <R2 / R1 ≦ 1.9 are set to be 25 kN or more here. If the ball joint portion 2 has a pulling strength and a punching strength of less than 25 kN, the ball portion 34 may be detached from the ball joint portion 2 when running on the axle side. It is trying to become. In particular, by using the above-described high-strength aluminum alloy and by setting the parting line PL in the ball joint portion 2f to a predetermined position, the strength of the ball joint portion 2 after machining can be maintained and reduced in size. Can be done smoothly.

  Therefore, as shown in FIG. 1, at the position facing the wheel 30 side, the joint center of the ball joint portion 2 can be brought closer to the tire center as compared with the conventional ball joint in which the parting line is formed at the center. The cross-sectional shape of the arm portion 6 of the suspension arm 1 may be formed in a U shape or an H shape.

  Further, as shown in FIG. 7 (a), the parting line PL is formed to have a gentle curve at the connecting portion between the arm flange portion 6f and the ball joint portion 2f, and the ball joint portion 2f is linear. It may be configured as follows. Further, as shown in FIG. 7B, the parting line PL extends linearly from the position of the arm portion 6f to a predetermined position (for example, the center) of the ball joint portion 2f, and then 0.4 W> h ≧ 0. It may be configured to be linearly formed toward the position h set at 2 W (see FIG. 3). At this time, the connecting portion may be configured to have a gentle curve (not shown) as described above. The parting line PL is perpendicular to the one end surface 3 or the other end surface 4 when the ball joint portion 2f is cut along the parting line P1, or the stud bolt neutral of the ball stud bolt 33. There is no particular limitation as long as it is a perfect circle or an approximate perfect circle when viewed from the direction SN.

  In addition, the parting line PL of the forged suspension member 1f has been described as a configuration in which the side wall portion 6f is arranged at the center in the thickness direction on the side surface, but is arbitrary in the range of the thickness direction E on the upper end side or lower end side of the side surface. For example, it is formed so as to be at the upper end side and the lower end side, and is formed toward the position h set at 0.4 W> h ≧ 0.2 W (see FIG. 3). You may comprise as follows.

  Further, the suspension arm or the forged suspension member is not particularly limited with respect to the joining posture of the arm portion and the ball joint portion. For example, as shown in FIG. 8, the arm portion 6A and the ball joint portion 2A have a predetermined shape. It may be configured to be connected at an inclination angle. In addition, about the same structure already demonstrated in FIG. 2, it attaches "A" after the same code | symbol and abbreviate | omits for details.

  As shown in FIG. 8, the parting line PL in the suspension arm 1A is formed such that the parting line P2 in the arm portion 6A is formed at the center position in the thickness direction on the side surface, and the party in the ball joint portion 2A. The ring line P1 is set and formed so as to be continuous with the position h (0.4W> h ≧ 0.2W (see FIG. 3)) on the side surface portion 5A which is the farthest position from the arm portion 6A. It is.

  The forged suspension member having the above-described configuration requires less thickness increase due to the draft angle, and can be reduced in size when machined to form a suspension arm, which is advantageous for the interference range of automobile wheels. Moreover, the strength required for the shape of the ball joint portion can be obtained with the minimum necessary material volume. Furthermore, it is possible to provide a forged suspension member as a suspension arm in which the joint center of the ball joint portion can be brought closer to the wheel center, the degree of freedom of design is widened, and the scrub radius can be reduced.

Further, as shown in FIG. 9, the forged suspension member 1f is provided with the ball joint portion 2f in a state in which the arm portion 6f and the ball joint portion 2f are inclined at a predetermined angle with respect to the arm portion 6f. It is good also as a structure. In the state of FIG. 9, the parting line PL is 0.4 W> h ≧ 0.2 W on the straight line where the parting line P2 of the arm portion 6f and the parting line P1 of the ball joint portion 2f are continuous. It is formed toward the position that becomes the range. The position h in the parting line P1 in FIG. 9 is also a position that is removed by machining.
As described above, the forged suspension member 1f is configured such that the position h of the parting line P1 on the side surface portion 5f of the ball joint portion 2f that is the farthest end portion from the arm portion 6f is 0.4W> h ≧ 0.2W. By setting the position to be in the range, it is possible to make the configuration effective for downsizing and caulking of the ball joint portion.

  It is sectional drawing which abbreviate | omitted partially showing the attachment position of the suspension arm concerning this invention.   It is a side view which shows the state which fractured | ruptured a part of suspension arm concerning this invention.   (A) is sectional drawing which shows the ball joint part of the forge suspension member concerning this invention, (b) is a perspective view which shows typically the state before the machining of the ball joint part of the forge suspension member concerning this invention. It is.   (A), (b) is a schematic diagram explaining the relationship of the area ratio of the one end surface part and other end surface part in the ball joint part of the suspension arm concerning this invention, and the axial cross section along a parting line.   It is a side view which shows typically the grain flow in the ball joint part of the forge suspension member concerning this invention.   (A), (b) is a top view which shows typically two types of the whole suspension arm concerning this invention as an example, respectively.   (A), (b) is a schematic diagram which each shows the other form of the parting line of the forge suspension member concerning this invention.   It is a side view which shows the state which fractured | ruptured partially in the other structure of the suspension arm concerning this invention.   It is a schematic diagram which shows the other structure of the forge suspension member concerning this invention.   (A) is sectional drawing which shows the state which fractured | ruptured the ball joint part of the conventional forged suspension arm, (b) is a schematic diagram which shows the grain flow in the ball joint part of the conventional forged suspension arm. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Suspension arm 1f Forged suspension member 2 Ball joint part 2f Ball joint part (in a forged suspension member)
3 One end surface portion 3f One end surface portion (in the forged suspension member)
4 Other end surface portion 4f Other end surface portion (in the forged suspension member)
5 Side surface portion 5f Side surface portion (for forged suspension member)
6 Arm part 6f Arm part (forged suspension member)
30 Wheel 31 Axle 32 Support member 33 Ball stud bolt (Stud bolt)
34 Ball part 35 Screw part 36 Body part 37 Dust cover 38 Interposition member C Center line GF Grain flow PL Parting line P1 Parting line (ball joint part)
P2 Parting line (arm part)
SN Stud bolt neutral direction T Forging press direction

Claims (10)

To form a suspension arm having a ball joint portion that is pivotally mounted on a support member supported on the axle side of an automobile via a stud bolt and that is attached so as to avoid an interference area with respect to an axle side part by machining. Forged suspension members of
The forged suspension member includes an arm portion, a ball joint portion provided at one end of the arm portion, a vehicle body side engaging portion provided at the other end of the arm portion, the arm portion, the ball joint portion, and the vehicle body. A parting line formed continuously at a predetermined position of the side engagement portion,
The ball joint portion includes one end surface portion, the other end surface portion facing the one end surface portion, and a side surface portion formed over the other end surface portion and the one end surface portion.
The position h of the parting line in the side surface portion of the ball joint portion which is the farthest position from the arm portion is from the one end surface portion or the other when the thickness dimension from the one end surface portion to the other end surface portion is W. A forged suspension member, which is provided within a range of a ratio represented by 0.4 W> h ≧ 0.2 W from the end surface portion. To form a suspension arm having a ball joint portion that is pivotally mounted on a support member supported on the axle side of an automobile via a stud bolt and that is attached so as to avoid an interference area with respect to an axle side part by machining. Forged suspension members of
The forged suspension member includes an arm portion, a ball joint portion provided at one end of the arm portion with an inclination at a predetermined angle, a vehicle body side engaging portion provided at the other end of the arm portion, the arm portion, A parting line formed continuously at a predetermined position of the ball joint part and the vehicle body side engaging part,
The ball joint portion includes one end surface portion, the other end surface portion facing the one end surface portion, and a side surface portion formed over the other end surface portion and the one end surface portion.
The position h of the parting line in the side surface portion of the ball joint portion which is the farthest position from the arm portion is from the one end surface portion or the other when the thickness dimension from the one end surface portion to the other end surface portion is W. A forged suspension member, which is provided within a range of a ratio represented by 0.4 W> h ≧ 0.2 W from the end surface portion.   3. The parting line of the ball joint part is formed so as to connect the position h in a straight line continuously from the position of the parting line of the arm part. The forged suspension member as described.   The parting line of the ball joint part is formed to continuously incline from the position of the parting line of the arm part into a curved line or a straight line so as to connect the positions h. The forged suspension member according to claim 1 or 2.   The parting line of the ball joint part is formed to extend to the center of the ball joint part in the state of the parting line of the arm flange part, and connects the position h from the center of the ball joint part. The forged suspension member according to claim 1 or 2, wherein the forged suspension member is formed into a shape.   The parting line of the ball joint part is formed in a peripheral line shape of a predetermined dimension along the periphery of the one end surface part or the other end surface part at the position h, and the arm from the both end positions of the peripheral line shape. The forged suspension member according to claim 1, wherein the forged suspension member is formed continuously with the parting line.   The forged suspension member according to any one of claims 1 to 6, wherein the parting line of the ball joint portion located in the interference region is disposed at a position where the parting line is removed by machining. In the suspension arm formed by machining the forged suspension member according to any one of claims 1 to 7,
When the radius of the ball ball diameter of the stud bolt engaged with the ball joint part of the suspension arm is R1, and the distance from the center of the ball joint part to the outermost part in the interference region of the ball joint part is a distance R2, 1.2 <R2 / R1 ≦ 1.9 A suspension arm, wherein the ball joint portion is formed at a ratio of 1.9.   The suspension arm according to claim 8, wherein the pull-out strength or the punch-out strength of the stud bolt is 25 kN or more.   10. The forged suspension member is made of an Al—Mg—Si based aluminum alloy having an average area ratio of sub-crystal grains in the structure of 60% or more and a 0.2% proof stress of 290 MPa or more. Suspension arm.

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