JP2014088113A - Steering knuckle for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering knuckle having a highly strong knuckle arm.SOLUTION: In a steering knuckle for a vehicle, having a knuckle arm 14 connected to a tie rod, at a tip 32, a shape of a cross section of an intermediate part 50, in an axial direction, of the knuckle arm is configured to be a shape in which a main axis Lis inclined by an angle θ', with respect to a projection line Lobtained by projecting a line parallel to a direction where force from the tie rod is applied, onto one plane including the cross section. Even when torsional stress is generated at the knuckle arm, the knuckle arm can be torsionally deformed in a direction where a direction of the main axis approaches a direction of bending stress. This structure enables the strength of the knuckle arm to be increased, when force from the tie rod is applied in a direction where the torsional deformation in the direction occurs.

Description

  The present invention relates to a vehicle steering knuckle that holds wheels in a steerable manner.

  A steering knuckle for a vehicle is a component of a steering system, and is a part that holds a wheel rotatably and allows the wheel to turn by its own rotation around a turning axis. This steering knuckle has a knuckle arm that extends from the knuckle body and is connected to a tie rod at the tip, and is rotated around the turning axis by the force that the knuckle arm receives from the tie rod. Due to such a structure, a relatively large bending stress is generated in the knuckle arm. Therefore, it is desirable to optimize the cross-sectional shape of the knuckle arm, and the following patent document proposes optimization of the cross-sectional shape with respect to an oblique bending stress.

JP-A-11-208501

  The inventor of the present application has found that there is a possibility that a torsional stress may be generated in addition to a bending stress in the knuckle arm during the development of the steering knuckle. And the knowledge that the intensity | strength of a knuckle arm can be improved by also considering the torsional stress was acquired. The present invention is based on this finding, and an object of the present invention is to provide a steering knuckle having a high-strength knuckle arm.

In order to solve the above problems, a vehicle steering knuckle according to the present invention includes:
A vehicle steering knuckle that has a knuckle arm that holds a wheel and is connected to a tie rod at a tip portion,
An intermediate portion in the axial direction of the knuckle arm is
The main axis of the cross section perpendicular to the axis of the knuckle arm is shaped so as to be inclined with respect to a projection line obtained by projecting a line parallel to the direction of action of the force from the tie rod onto one plane including the cross section. It is characterized by.

  The steering knuckle of the present invention can be configured such that even if a torsional stress is generated in the knuckle arm, the knuckle arm is torsionally deformed in a direction in which the direction of the main axis approaches the direction of the bending stress. With such a configuration, it is possible to increase the strength of the knuckle arm when a force from the tie rod is applied in a direction in which torsional deformation in that direction occurs.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

  In the following items, each of items (1) to (6) corresponds to each of claims 1 to 6.

(1) A vehicle steering knuckle that holds a wheel and has a knuckle arm that is connected to a tie rod at a tip portion,
An intermediate portion in the axial direction of the knuckle arm is
A vehicle having a shape in which a principal axis of a cross section perpendicular to the axis of the knuckle arm is inclined with respect to a projection line obtained by projecting a line parallel to an action direction of a force from the tie rod onto one plane including the cross section. Steering knuckle.

  The mode of this section is an effective mode in the case where not only bending stress but also torsional stress is generated in the knuckle arm (hereinafter sometimes simply referred to as “arm”) when the force from the tie rod is applied. is there. If the direction in which the main axis of the cross section of the intermediate portion extends due to the torsional deformation of the arm approaches the bending direction of the arm, the strength of the arm, specifically, the strength of the arm against bending stress increases.

  The “axis of the knuckle arm” in this aspect can be considered as a central axis that penetrates the arm in the longitudinal direction, or a neutral axis (neutral axis), and the “axis direction of the knuckle arm” refers to a direction in which the axis extends. Can think. The “intermediate portion of the knuckle arm in the axial direction” means a portion existing between a base end portion (a portion connected to the knuckle body) and a distal end portion (a portion to which the tie rod is connected) in the arm extending direction. . The intermediate portion is generally relatively thin compared to the distal end portion and the proximal end portion, and can be considered as the weakest portion (the deformation is increased), that is, the weakest portion of the arm. Therefore, in this embodiment, the strength of the arm can be increased without increasing the cross-sectional area of the arm by making the cross-sectional shape of the weakest portion as described above.

  In addition, the “main axis of the cross section” in this aspect can be considered as an axis orthogonal to the axis where the cross sectional secondary moment is maximum. Specifically, for example, assuming a rectangular cross-section, the line connecting the midpoints of the two long sides facing each other corresponds to the axis that maximizes the cross-sectional secondary moment, and the midpoint of the two short sides facing each other A line connecting the lines corresponds to the main axis. Furthermore, the “direction of the force applied from the tie rod” is the direction of the force received by the tip of the arm from the tie rod, and is generally a direction that is generally horizontal, and the “projection line” in this embodiment is generally The line is almost horizontal.

(2) The knuckle arm is
The vehicle steering knuckle according to (1), wherein the vehicle steering knuckle is connected to the tie rod via a ball joint, and has a connecting hole into which a stud portion of a ball stud of the ball joint is vertically inserted.

  The mode of this section is a typical mode in which torsional stress is generated in the arm. Generally, the ball joint includes a ball stud including a stud portion and a ball portion attached to one end of the stud portion, and a housing that rotatably holds the ball portion of the ball stud. . In a connection structure employing such a ball joint, a housing is generally attached to the tip of the tie rod, and the stud is inserted into a connection hole formed in the tip of the arm. . In such a connecting structure of the arm and the tie rod, the stud portion can be tilted relatively freely with respect to the tie rod. Therefore, a force for twisting the arm acts on the tip portion of the arm. Torsional stress is generated in the arm, and the arm is torsionally deformed. Therefore, the technical features of the aspects of the respective items can exert a sufficient effect on the steering knuckle in which the arm is connected to the tie rod by such a coupling structure.

(3) The intermediate portion is
The main axis is projected to the side where the inclination of the main axis to the projection line becomes smaller due to the twisting of the knuckle arm when a force in the direction toward the outside of the vehicle acts on the tip of the knuckle arm from the tie rod. The vehicle steering knuckle according to (1) or (2), wherein the steering knuckle is configured to be inclined with respect to a line.

  The closer the extension of the main axis is to the bending direction, the higher the strength against bending stress. Therefore, if the main axis approaches the direction of bending due to torsional deformation, the strength of the arm against bending increases. In this aspect, the main axis approaches the bending direction when a force in the direction toward the outside of the vehicle acts on the tip of the arm from the tie rod. The situation in which the force in the direction toward the outside of the vehicle acts on the tip of the arm from the tie rod is reversed. The situation is caused by an event such as riding on the curb of the wheel, wheel removal, or collision of some object with the wheel. That is, when such an event occurs, a large reaction force acts on the arm from the tie rod, and therefore the strength of the arm in the situation is particularly important. According to this aspect, the strength of the arm in the situation can be increased.

  (4) In the items (1) to (3), the intermediate part has a shape having a depression on one of two surfaces facing each other across the main axis of the outer peripheral surface of the intermediate part. The steering knuckle for vehicles as described in any one.

  For example, when the arm is twisted, the distance between the center of rotation of the arm (also referred to as “rigid”) and the point of action of the force (which can also be thought of as a projection point on the cross section of the actual point of action) It is possible to reduce torsional stress, that is, torsional deformation. According to this aspect, by forming a recess (recess) in one of the two surfaces in the intermediate portion of the arm, the distance between the rotation center and the force application point in the cross section of the intermediate portion can be reduced. Is possible. By making the intermediate portion have such a cross-sectional shape, the strength of the arm against torsion can be increased.

  In addition, at the site where the coupling between the bending stress and the torsional stress occurs (it can also be considered as the site where the coupling between the tensile stress resulting from bending and the shearing stress resulting from torsion occurs), that is, the two stresses It is considered that the strength is the lowest at the sites that promote each other. In this aspect, the presence of the depression makes it possible to provide an intermediate portion having a shape as if a convex portion is formed between a portion where the bending stress is maximized and a portion where the torsional stress is maximized. . In other words, the cross section can have a shape in which a protrusion is provided between the surface provided with the recess and the surface adjacent to the surface. For example, the torsional stress is maximized on the surface provided with the recess. And that the bending stress is maximized on the surface adjacent to that surface, and effectively, the bending stress and the torsional stress are coupled effectively. Coupling can be prevented. By setting it as such an arm, the intensity | strength of the arm will increase.

(5) The knuckle arm is
It is connected to the tie rod via a ball joint, and has a connecting hole into which the stud portion of the ball stud of the ball joint is fitted vertically in the tip portion.
According to the positional relationship in the vertical direction between the stud portion and the ball portion of the ball stud, one side in the vertical direction is a ball side direction that is a direction from the stud portion toward the ball portion, and the other is from the ball portion to the stud portion. The stud side direction, which is a direction toward the center, and the intermediate portion, when defined respectively, is a shape having the depression in the surface facing the stud side direction, out of the two surfaces. Steering knuckle for vehicles.

  This mode is a mode in which the formation position of the depression is limited in the previous mode in which the arm and the tie rod are connected via the ball joint. In the connection mode using the ball joint, the center of the ball portion of the ball stud constituting the ball joint is the point of action of the force. Therefore, as in this aspect, the distance between the action point and the above-mentioned rotation center can be reduced by providing the depression on the opposite surface of the ball joint. As a result, the strength against the torsional stress of the arm can be increased.

  (6) The main axis of the cross section is inclined with respect to the projection line so that an angle formed by the main axis is 40 ° or more and 50 ° or less, according to any one of (1) to (5) Steering knuckle for vehicles.

  According to this aspect, when the arm is twisted at a considerable angle, the extending direction of the main axis coincides with the extending direction of the projection line. The situation where the angle is twisted to such an angle is a situation where the arm must be broken. That is, this aspect is an aspect in which the strength of the arm is improved in consideration of the breakage of the arm.

It is the figure which looked at the steering knuckle for vehicles from the vehicle center side in the vehicle width direction toward the vehicle outer side. It is a perspective view which expands and shows the knuckle arm of the steering knuckle for vehicles. It is a figure which shows the mode of a deformation | transformation of a knuckle arm when force acts on a knuckle arm from a tie rod. It is a figure which shows the cross-sectional shape of the intermediate part of the knuckle arm which the conventional steering knuckle has, and the cross-sectional shape of the intermediate part of the knuckle arm which the steering knuckle of an Example has. It is a figure which shows a mode that an intermediate part rotates with a bending force while showing the bending force and torsional force which act on the intermediate part of the knuckle arm which the conventional steering knuckle has. It is a figure for demonstrating two means to improve the intensity | strength with respect to the knuckle arm of the conventional steering knuckle. It is a figure which shows the knuckle arm which the steering knuckle of an Example has from the viewpoint opposite to FIG. How to change the inclination direction of the middle part of the knuckle arm depending on whether the steering knuckle of the embodiment is for the right wheel or the left wheel, or the knuckle arm extends to the front side or the rear side of the vehicle It is a figure for demonstrating what to do. It is a figure which shows a mode that the knuckle arm of the steering knuckle of an Example is shape | molded using a type | mold.

  Hereinafter, as a form for carrying out the claimable invention, a vehicle steering knuckle which is an embodiment of the claimable invention will be described in detail with reference to the drawings. In addition to the following examples, the claimable invention is implemented in various forms including various modifications and improvements based on the knowledge of those skilled in the art, including the form described in the above [Aspect of the Invention] section. can do.

  Hereinafter, regarding the vehicle steering knuckle of the embodiment, in order to improve the basic structure of the vehicle steering knuckle, the torsional deformation of the knuckle arm and the strength of the knuckle arm and knuckle arm of the conventional vehicle steering knuckle. The knuckle arm which the steering knuckle for vehicles of this means and the embodiment has will be described in order.

<< 1. Basic structure of steering knuckle for vehicles >>
A steering knuckle 10 as an example of a vehicle steering knuckle that is a subject of the claimable invention includes a knuckle body 12 and a knuckle arm 14 extending from the knuckle body 12, as shown in FIG. 1. The steering knuckle 10 is a part of a strut mount type (McPherson type) suspension device, and the knuckle body 12 is fixed to a shock absorber 16 at an upper portion and supported holes 18 provided at a lower portion. The lower arm 20 is rotatably and tiltably supported via a ball joint (not shown). Further, the knuckle body 12 is provided with a shaft hole 22 into which a bearing (not shown) is inserted, and an axle (not shown) is rotatably held in the shaft hole 22 via the bearing. . A wheel (not shown) is attached to the axle. Further, the knuckle body 12 is provided with two brackets 26 for attaching the brake caliper 24.

  Referring to FIG. 2 as well, the knuckle arm 14 (hereinafter sometimes simply referred to as “arm 14”) is integrated with the knuckle body 12 at the base end portion 30, and at the distal end portion 32. The tie rod 36 is connected via a ball joint 34. The ball joint 34 includes a ball stud 42 including a ball portion 38 and a stud portion 40, and a housing 44 that is fixed to the tip of the tie rod 36 and supports the ball stud 42 rotatably and tiltably at the ball portion 38. In the state where the stud portion 40 of the ball stud 42 fits into the connecting hole 46 drilled through the distal end portion 32 of the arm 14 in the vertical direction, the distal end portion 32 thereof. To be concluded. In the arm 14, the distal end portion 32 is positioned higher than the proximal end portion 30, and the intermediate portion 50 that is an intermediate portion between the proximal end portion 30 and the distal end portion 32 is bent in the vertical direction. I am doing.

  The steering knuckle 10 is for the right front wheel. In FIG. 1, the left side is the front of the vehicle. As can be seen from FIG. 1, in the steering knuckle 10, the arm 14 extends from the knuckle body 12 generally toward the rear of the vehicle. The tie rod 36 can be reciprocated in the vehicle width direction according to the rotation operation of the steering wheel. When the right end of the tie rod 36 moves toward the outside of the vehicle, that is, from the tie rod 36 to the arm 14. When a force in a direction toward the right side of the vehicle acts on the front end portion 32 of the vehicle, the steering knuckle 10 is rotated counterclockwise as viewed from above, and the wheels face left (the vehicle turns left). It is steered to. Conversely, when the right end of the tie rod 36 moves toward the center of the vehicle, that is, when a force in the direction toward the left side of the vehicle acts on the tip 32 of the arm 14 from the tie rod 36, By the force, the steering knuckle 10 is rotated clockwise as viewed from above, and the wheels are steered to the right (the direction in which the vehicle turns to the right).

≪2. Torsional deformation of knuckle arm and conventional knuckle arm >>
In the steering knuckle 10 having the above-described basic configuration, when a force F (hereinafter sometimes referred to as “acting force F”) is applied to the distal end portion 32 of the arm 14 from the tie rod 36, the arm 14 Added torsional deformation. Specifically, for example, when a force is applied in the direction of the white arrow in FIG. 2, the point of action of the force is considered to be the center of the ball portion 38 of the ball stud 42 of the ball joint 34. In addition to the bending force, a torsional force acts on the distal end portion 32 of the arm 14 and deforms as shown by a two-dot chain line in FIG.

The arm 14 of the conventional steering knuckle 10 has an intermediate portion 50 having a cross-sectional shape as shown in FIG. 4 (a). As shown in FIG. If, its middle section 50, in addition to the bending force F _B, torsional force F _T is acting. That is, torsional stress is generated in addition to bending stress. Incidentally, the action point A and the action force F shown in FIG. 5 are strictly projected on one plane including the cross section. Further, the cross-sectional shape of the intermediate portion 50 of the arm 14 of the conventional steering knuckle 10 can be regarded as a generally rectangular shape with the upper and lower sides being long sides. As shown in FIG. 5 (a), the axis L _Y having the maximum cross-sectional secondary moment extends in the vertical direction, and the axis L _X perpendicular to the axis L _Y , that is, the main axis L _X is substantially horizontal. The posture extends in the direction. Then, the center of gravity O of the cross section and the rotation center O ′ of the cross section due to the action of the torsional force F _T can be handled as substantially coincident. Incidentally, since the arm 14 is formed of a homogeneous material, the center of gravity O coincides with the centroid, and the rotation center O ′ can also be called a rigid center O ′.

When a force is applied to the wheel from the outside, the above-described acting force F as a reaction force of the tie rod 36 is generated, and when the force from the outside, that is, the acting force F becomes considerably large, the cross section has a torsional force. By the action of F _T , the center rotates about the center of rotation O ′ substantially coincident with the center of gravity O, and is tilted by the tilt angle θ to change to the posture shown in FIG. In this case, the principal axis L _X is inclined and bent with respect to the direction of the acting force F, strictly speaking, with respect to the projection line L _P obtained by projecting a line parallel to the direction of the acting force F onto the plane including the cross section. The cross-sectional second moment with respect to the force F _B is reduced, and the amount of bending deformation is relatively large. That is, the rigidity of the arm 14 with respect to bending is reduced.

Further, regarding the generated bending stress and torsional stress, as shown in FIG. 5A, the tensile stress resulting from the bending stress is represented as the short side on the left side of the outer peripheral surface of the intermediate portion 50. The shear stress caused by the torsional force stress increases in the portion P _A constituting the formed surface, and one of the two surfaces sandwiching the principal axis L _X of the outer peripheral surface of the intermediate portion 50, In the portion P _B constituting the surface represented as the upper long side in FIG. If these portions P _A and P _B are referred to as a bending-induced large stress portion P _A and a torsion-induced large stress portion P _B , respectively, corner portions P _{C at} which the surfaces constituting each of these portions intersect, that is, in part P _C where those surfaces are continuous, coupled two stress is generated, the stress of the part P _C is the largest. In other words, call a that portion P _C and the maximum stress portion P _C, the maximum stress portion P _C and the vicinity thereof becomes lowest the weak portion of the strength. Incidentally, in FIG. 2, the weakest part P _W is shown by shading, and the existence of such a weakest part P _W caused by the coupling of the stress is a large one that reduces the strength of the arm 14. It is a cause.

≪3. Means for improving the strength of the knuckle arm >>
As a first means for improving the strength of the arm 14, as shown in FIG. 6 (a), the intermediate axis 50 has the main axis L _X described above in a state where the acting force F from the tie rod 36 does not act. It can be considered that the cross-sectional shape is inclined with respect to the projection line L _P. More specifically, the cross-sectional shape of the intermediate portion 50 is inclined with respect to a projected inclination angle θ ′ with respect to a projection line L _F obtained by projecting a line parallel to the direction of action of the acting force F onto one plane including the section. It is a shape. This means is based on the premise that a torsional force F _T acts on the intermediate part 50 of the tie rod 36, and the main axis L _X when the intermediate part 50 is rotated by a predetermined inclination angle θ ′ by the action of the torsional force F _T. Is a means for inclining the main axis L _X in advance so as to coincide with the projection line L _P. By adopting this means, when acts considerably large operating force F, bending force direction of extension of the direction and the major axis L _X of F _B match, the bending deformation when the operating force F acts reduced It can be done. That is, the bending rigidity of the intermediate portion 50 of the arm 14 can be increased.

As a second means for improving the strength of the arm 14, as shown in FIG. 6B, the cross-sectional shape of the intermediate portion 50 is set so that one of the upper and lower sides, that is, the main axis L _X is sandwiched therebetween. It can be considered to have a shape having a recess 52 on one of two sides facing each other. Specifically, in the vertical direction, when the direction from the stud portion 40 of the ball stud 42 toward the ball portion 38 is defined as the ball side direction, and the direction from the ball portion 38 toward the stud portion 40 is defined as the stud side direction. The upper surface, which is the surface facing the stud side direction of the intermediate portion 50, has a shape having a recess 52. That is, a depression (also referred to as a “recess”) 52 is provided on a surface far from the point of action A of the acting force F in the vertical direction.

Although a detailed description is omitted, the distance between the rotation points of the action points, which is the distance in the vertical direction between the rotation center O ′ and the action point A of the action force F, is d, and the sectional secondary pole moment of the intermediate portion 50 is I _P. If the lateral elastic modulus of the intermediate portion 50 is expressed as G, the inclination angle θ of the intermediate portion 50 of the arm 14 can be expressed by the following equation.
θ = (F · d) / (G · I _P )
According to the above equation, it can be understood that the inclination angle θ becomes smaller as the distance d between the action point rotation centers is smaller.

As shown in FIG. 5, the distance d between the action point rotation centers of the arms 14 of the conventional steering knuckle 10 is d _A , whereas in the arm 14 in which the recess 52 is formed as described above, the action point rotation center. The distance d is as small as d _B (<d _A ). Since this theory is a pure material dynamic theory, the description thereof will be omitted. However, by forming the recess 52, the distance d between the rotation points of the action points is reduced, and as a result, the same action force F is obtained. The inclination angle θ of the cross section when it acts, that is, the amount of torsional deformation of the intermediate portion 50 is reduced. That is, by providing the recess 52, the torsional rigidity of the intermediate portion of the arm 14 can be increased.

Further, by providing the recess 52, the intermediate portion 50 is as if between the surface represented as the left short side and the upper surface represented as the upper long side in the cross section thereof. The projection 54 (which may also be referred to as a “convex portion”) 54 is provided. The presence of the protrusion 54 avoids or reduces the coupling of the bending stress and the torsional stress at the portion where the bending-induced large stress portion P _A and the torsion-induced large stress portion P _B are continuous. As a result, the strength of the portion that has been the weakest portion P _W in the arm 14 of the conventional steering knuckle 10 is increased.

<< 4. The knuckle arm of the steering knuckle of the embodiment >>
In the steering knuckle 10 of the embodiment, both of the above-described two means for improving the strength of the arm 14 are adopted, and the intermediate portion 50 is configured to have the arm 14 having the cross-sectional shape shown in FIG. ing. That is, the intermediate portion 50 is inclined with respect to the projection line L _{P with} respect to the main axis L _X with a predetermined inclination angle θ ′, and one of two sides facing each other across the main axis L _X , that is, the stud. A shape having a recess 52 on the upper surface, which is a surface facing the side direction, is used. Incidentally, FIG. 7 shows the arm 14 from a viewpoint opposite to that in FIG. 1. In the figure, a depression 52 is shown by shading, and the depression 52 is formed on the proximal end portion 30. As it approaches, it becomes shallower smoothly, and as it approaches the tip 32, it becomes shallower. Note that the planned inclination angle θ ′ also gradually decreases as it approaches the proximal end portion 30 and gradually decreases as it approaches the distal end portion.

Speaking of the inclination direction of the main axis L _X , that is, the inclination direction of the intermediate portion 50 of the arm 14, the intermediate portion 50 is in the case where a force in the direction toward the vehicle outer side acts on the distal end portion of the arm 14 from the tie rod 36. The arm 14 is twisted so that the inclination angle θ of the main axis L _X with respect to the projection line L _P is inclined toward the side where the inclination angle θ decreases. Further, the planned inclination angle θ ′ is set to 40 ° or more and 50 ° or less (about 45 ° in the figure). That is, when the arm 14 is twisted substantial angle, direction projected line L _P and the direction of extension of the major axis L _X extends coincides (tilt angle θ is 0 ° to become) are adapted. Therefore, the steering knuckle 10 of the embodiment is designed to assume a situation where the arm 14 may be broken.

  The steering knuckle 10 of the embodiment having the arm 14 shown in FIGS. 4 and 7 is a steering knuckle 10 for the right front wheel and the arm 14 extending from the knuckle body 12 to the vehicle rear side. The steering knuckle 10 of the embodiment is also intended for a steering knuckle for a left wheel and a steering knuckle with an arm 14 extending to the front side of the vehicle. As schematically shown in FIG. 8, the inclination of the arm 14 depends on whether it is for the right wheel 60R or the left wheel 60L, and whether the arm 14 extends toward the vehicle front side or the vehicle rear side. You can change the direction of. 8 (a), (b), (c), and (d) are for the right wheel 60R and the arm 14 extends to the vehicle rear side, and for the left wheel 60L, the arm 14 is on the vehicle rear side. The cross section of the intermediate portion 50 of each of the extended arm, the right wheel 60R for the right wheel 60R, the arm 14 extending to the vehicle front side, and the left wheel 60L for the arm 14 extending to the vehicle front side is shown.

  Incidentally, the steering knuckle 10 of the embodiment is formed by forging, casting, or the like, for example. In that case, two molds are used, these two molds are closed, and forging, casting, and the like are performed. That is, molding is performed using a pair mold (die set) in which the mold surface that forms the cavity with the two molds closed is the outer peripheral surface of the steering knuckle 10. When forming the arm 14 with such a pair, the two molds are arranged on the front side and the back side of the arm 14 in FIG. 1, and the intermediate portion 50 of the arm 14 is formed as shown in FIG. The As can be seen from this figure, even if the recess 52 is provided in the intermediate portion 50 of the arm 14, the molding can be easily performed by the two molds 70 and 72. Specifically, by configuring the two molds 70 and 72 as shown in the drawing, the recess 52 separates the molds 70 and 72 from each other (the two molds are separated from each other to take out the product). Does not inhibit). In other words, by providing the recess 52, the molds 70 and 72 can be smoothly released without being caught by the convex portions 74 and 76 adjacent to the recess 52.

10: Steering knuckle 12: Knuckle body 14: Knuckle arm 30: Base end portion 32: Tip end portion 34: Ball joint 36: Tie rod 38: Ball portion 40: Stud portion 42: Ball stud 44: Housing 46: Connecting hole 50: Intermediate Part (intermediate part) 52: depression 54: protrusion F: acting force (force acting on the tip of the knuckle arm from the tie rod) F _B : bending force F _T : twisting force A: acting point O: center of gravity O ': center of rotation (Tsuyoshikokoro) L _X: main axis L _Y: axial second moment is maximized L _P: projection line of a line parallel to the direction of the applied force theta: the inclination angle theta ': planned inclination angle P _a: bending due overstress section P _B: torsional due overstress section P _C: maximum stress portion P _W: weak portion d _A, d _B: distance between the point the center of rotation

Claims (6)

A vehicle steering knuckle that has a knuckle arm that holds a wheel and is connected to a tie rod at a tip portion,
An intermediate portion in the axial direction of the knuckle arm is
A vehicle having a shape in which a principal axis of a cross section perpendicular to the axis of the knuckle arm is inclined with respect to a projection line obtained by projecting a line parallel to an action direction of a force from the tie rod onto one plane including the cross section. Steering knuckle. The knuckle arm is
2. The vehicle steering knuckle according to claim 1, wherein the steering knuckle for a vehicle is connected to the tie rod via a ball joint, and has a connecting hole into which a stud portion of a ball stud of the ball joint is vertically inserted at the tip portion. The intermediate portion is
The main axis is projected to the side where the inclination of the main axis to the projection line becomes smaller due to the twisting of the knuckle arm when a force in the direction toward the outside of the vehicle acts on the tip of the knuckle arm from the tie rod. The steering knuckle for a vehicle according to claim 1 or 2, wherein the steering knuckle is configured to be inclined with respect to a line.   The intermediate portion according to any one of claims 1 to 3, wherein the intermediate portion has a shape having a recess on one of two surfaces facing each other across the main axis of the outer peripheral surface of the intermediate portion. The steering knuckle for vehicles as described. The knuckle arm is
It is connected to the tie rod via a ball joint, and has a connecting hole into which the stud portion of the ball stud of the ball joint is fitted vertically in the tip portion.
According to the positional relationship in the vertical direction between the stud portion and the ball portion of the ball stud, one side in the vertical direction is a ball side direction that is a direction from the stud portion toward the ball portion, and the other is from the ball portion to the stud portion. 5. The vehicle according to claim 4, wherein the intermediate portion has a shape having the depression in a surface facing the stud side direction of the two surfaces when each is defined as a stud side direction that is a direction toward the stud. Steering knuckle. The vehicle steering knuckle according to any one of claims 1 to 5, wherein the main axis of the cross section is inclined with respect to the projection line so that an angle formed by the main axis is not less than 40 ° and not more than 50 °. .

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