A knuckle and hydraulic tooling thereof

Abstract

The application discloses a steering knuckle and a hydraulic tool thereof. The steering knuckle is provided with a circular-arc groove between two first mounting holes on the lower surface of a lower control connecting arm, and the quantitative relationship of the curvature radius R of the circular-arc groove, the thickness W of the lower control connecting arm and the inclination angle θ satisfies R≥λ·W·sin 2 θ (1≤λ≤2), so that the stress concentration caused by the additional bending moment generated between the two first mounting holes by the transverse component force of the vertical load from the road when the vertical load is transmitted through the inclined lower control connecting arm is effectively relieved. The circular-arc groove changes the original planar stress transmission path into a curved surface transition, and the stress line is forced to be redistributed along the tangential direction of the circular arc, so that the peak stress is dispersed from the hole edge and the bifurcation root to a larger curved surface area, thereby significantly reducing the stress concentration coefficient and the fatigue stress amplitude of the area.

Description

Technical Field

[0001] This invention relates to the field of automotive steering knuckle technology, specifically to a steering knuckle and its hydraulic tooling. Background Technology

[0002] As a key load-bearing component of the automotive chassis suspension system, the steering knuckle is connected to the wheel hub assembly at one end through the wheel hub bearing mounting hole, and at the other end through various connecting arms to the suspension lower control arm, steering tie rod, shock absorber, and brake caliper, etc. During vehicle operation, it continuously bears the combined effects of vertical impact loads from the road surface, longitudinal braking and driving forces, and lateral steering forces. Its structural strength and fatigue reliability are directly related to the handling stability and driving safety of the entire vehicle.

[0003] In existing technologies, to achieve a two-point connection with the lower control arm of the suspension, the lower control arm of the automotive steering knuckle typically employs a bifurcated structure. This bifurcated structure has two spaced-apart mounting holes at its ends to mate with the ball joints or bushings of the lower control arm, respectively. However, this bifurcated structure makes the area between the two mounting holes a critical transition section in the force transmission path. When the vehicle travels over bumpy roads or undergoes emergency braking, this transition section must simultaneously withstand the reverse shear forces from both mounting holes, as well as the bending moment coupling effect caused by suspension bounce. Because existing lower control arms often use planar or simple circular arc transition designs in this area, the stress concentration factor is high, and alternating stress easily leads to fatigue cracks at the hole edges and the bifurcated root.

[0004] Furthermore, to adapt to the suspension geometry and meet steering performance requirements, the lower control arm is typically arranged in an inclined direction. This inclination angle causes the vertical load from the road surface to be decomposed on the lower control arm into an axial component along the arm length and a lateral component perpendicular to the arm length, thereby generating a significant additional bending moment in the area between the two mounting holes. Under long-term alternating loads, this inclined arrangement exacerbates the cycle of tensile and compressive stresses in the area between the mounting holes, making this part a weak point in the fatigue life of the entire steering knuckle. Especially under high load cycle conditions, existing structures struggle to effectively disperse the peak stress in this area, significantly increasing the risk of fatigue failure.

[0005] To address the aforementioned issues, existing technologies typically employ methods such as increasing the local wall thickness of the lower control arm or adding simple reinforcing ribs to improve structural strength. However, simply adding material not only increases the overall weight of the steering knuckle, contradicting current automotive lightweight design trends, but also fails to fundamentally alter the stress distribution in stress concentration areas, allowing fatigue cracks to propagate along the ends of reinforcing ribs or at abrupt changes in wall thickness. Furthermore, existing reinforcing rib layouts often fail to adequately consider the coupling effect between the lower control arm's tilt angle and the bifurcation structure, making it difficult to effectively alleviate fatigue stress concentration in the area between mounting holes. Therefore, optimizing the bifurcation structure and tilt arrangement of the lower control arm while ensuring lightweight design to effectively reduce fatigue stress in the area between mounting holes and improve overall structural strength has become a pressing technical problem in this field. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, the present invention provides a steering knuckle and its hydraulic tooling to solve at least some of the technical problems mentioned in the background art.

[0007] To achieve the above objectives, a first aspect of the present invention provides a steering knuckle for an automobile, comprising: The steering knuckle body has a hub bearing mounting hole at its center. The lower control connecting arm is located on the left side of the steering knuckle body along an inclined downward extension direction. The lower control connecting arm has a forked structure and two first mounting holes are provided at the end of the lower control connecting arm at intervals. A steering tie rod connecting arm is disposed on the rear side of the steering knuckle body along an extension direction perpendicular to the lower control connecting arm, and a second mounting hole is provided at the end of the steering tie rod connecting arm; A shock absorber connecting arm is provided on the right side of the steering knuckle body along an extension direction opposite to that of the lower control connecting arm, and a third mounting hole is provided at the end of the shock absorber connecting arm; The brake caliper mounting part is located on the front side of the shock absorber connecting arm and includes a first lug and a second lug that are spaced apart. The first lug and the second lug are respectively provided with brake caliper mounting holes. The lower surface of the lower control connecting arm has an arcuate groove located between the two first mounting holes. The radius of curvature of the arcuate groove is R, and the tilt angle of the lower control connecting arm is θ; where R ≥ λ⋅W⋅sin 2 θ, 1≤λ≤2, W is the thickness of the lower control connecting arm at the center of the arc groove.

[0008] Optionally, the bifurcated structure of the lower control connecting arm includes a first bifurcated end and a second bifurcated end, and the two first mounting holes are respectively located at the first bifurcated end and the second bifurcated end; one end of the arcuate groove is connected to the first bifurcated end, and the other end of the arcuate groove is connected to the second bifurcated end.

[0009] Optionally, the upper surface of the lower control connecting arm is also provided with reinforcing ribs.

[0010] Optionally, the first lug and the second lug are provided with raised positioning steps on the side facing the wheel hub bearing mounting hole for radial positioning engagement with the brake caliper bracket; and the first lug and the second lug are arranged in a figure-eight shape.

[0011] Optionally, the steering knuckle body is further provided with a sensor mounting boss, which is located below the wheel hub bearing mounting hole and close to the steering tie rod connecting arm; the sensor mounting boss is provided with a fastening hole for fastening the wheel speed sensor.

[0012] A second aspect of the present invention provides a hydraulic tooling for machining a steering knuckle as described above; wherein the hydraulic tooling comprises: A fixture base having a horizontal work surface; A left clamping unit and a right clamping unit are symmetrically and spaced apart on the horizontal worktable of the clamp base. The left clamping unit and the right clamping unit are used to clamp the two steering knuckles respectively. The left clamping unit and the right clamping unit each include a positioning component and a hydraulic clamping component. The positioning component includes a central positioning pin for engaging with the central wheel hub bearing hole, and a plurality of bottom support columns arranged around the central positioning pin. The top end faces of the plurality of bottom support columns are respectively adapted to the contour surfaces of the lower control connecting arm, the steering tie rod connecting arm, the shock absorber connecting arm, and the brake caliper mounting part. The hydraulic clamping component includes at least two sets of hydraulic clamping mechanisms. The hydraulic clamping mechanisms are respectively arranged around the central positioning pin and are used to clamp and fix the ends of each arm of the steering knuckle to the bottom support columns under hydraulic drive.

[0013] Optionally, the hydraulic clamping assembly includes: A hydraulic cylinder is installed inside the fixture base; The clamping arm has one end connected to the piston rod of the hydraulic cylinder and the other end equipped with a clamping block; When the hydraulic cylinder is activated, the clamping blocks press against the upper parts of the shock absorber connecting arm, steering tie rod connecting arm, and lower control connecting arm of the steering knuckle, respectively.

[0014] Optionally, a hydraulic distribution valve block is provided on the fixture base between the left clamping unit and the right clamping unit. The hydraulic distribution valve block synchronously distributes a uniform hydraulic pressure to each hydraulic cylinder of the left clamping unit and the right clamping unit to achieve synchronous locking of the left and right dual positions.

[0015] Optionally, the top of the bottom support column is provided with a hemispherical or conical contact head.

[0016] Optionally, both the left and right clamping units are provided with bottom pads at their bottoms. The bottom pads elevate the left and right clamping units as a whole, forming a gap below the steering knuckle for the machining tool to avoid and for chip removal.

[0017] The specific implementation effect of this invention is as follows: by setting an arc groove between the two first mounting holes on the lower surface of the lower control connecting arm, and limiting the radius of curvature R of the arc groove to satisfy R≥λ·W·sin 2 The quantitative relationship θ (1≤λ≤2) effectively alleviates the stress concentration caused by the additional bending moment generated between the two first mounting holes when the vertical load from the road surface is transmitted through the inclined lower control connecting arm. This arc-shaped groove transforms the original planar stress transmission path into a curved transition, forcing the stress lines to redistribute along the tangential direction of the arc. The peak stress is dispersed from the hole edge and the root of the bifurcation to a larger curved area, thereby significantly reducing the stress concentration factor and fatigue stress amplitude in this region. Simultaneously, the sin in the relationship... 2 The θ term reflects the amplification effect of the tilt angle on the bending moment effect, the W term ensures that the radius of curvature matches the local structural stiffness, and the range of λ values ​​provides a safety margin for the strength requirements of different working conditions. Ultimately, the structural strength and fatigue life of the lower control connecting arm are effectively improved without significantly increasing the structural weight. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a steering knuckle according to the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of a steering knuckle according to the present invention. Figure 2 ; Figure 3 This is a top view of a steering knuckle according to the present invention; Figure 4 In this invention Figure 3 A sectional view; Figure 5 This is a schematic diagram of the structure of a hydraulic tooling according to the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1. Steering knuckle body; 2. Wheel hub bearing mounting hole; 3. Lower control arm connecting arm; 3a. First mounting hole; 3b. Recessed weight reduction groove; 4. Steering tie rod connecting arm; 4a. Second mounting hole; 5. Shock absorber connecting arm; 5a. Third mounting hole; 6. Brake caliper mounting part; 6a. First lug; 6b. Second lug; 6c. Brake caliper mounting hole; 7. Reinforcing rib structure; 8. Sensor mounting boss; 8a. Fastening hole; 9. Clamp base; 10. Left clamping unit; 11. Right clamping unit; 12. Center positioning pin; 13. Bottom support column; 14. Hydraulic clamping mechanism; 14a. Hydraulic cylinder; 14b. Clamping arm; 14c. Clamping block; 15. Bottom pad. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1-4 As shown, the first aspect of the present invention provides a steering knuckle for automobiles. The steering knuckle includes a steering knuckle body 1, a lower control connecting arm, a steering tie rod connecting arm 4, a shock absorber connecting arm 5, and a brake caliper mounting portion 6. The steering knuckle body 1 has a hub bearing mounting hole 2 at its center. The lower control connecting arm is located on the left side of the steering knuckle body 1 along a downwardly extending direction, and has a forked structure with two first mounting holes 3a spaced apart at its end. The steering tie rod connecting arm 4 is located on the rear side of the steering knuckle body 1 along a direction perpendicular to the lower control connecting arm, and has a second mounting hole 4a at its end. The shock absorber connecting arm 5 is located on the right side of the steering knuckle body 1 along a direction opposite to the lower control connecting arm, and has a third mounting hole 5a at its end. The brake caliper mounting portion 6 is located on the front side of the shock absorber connecting arm 5 and includes a first lug 6a and a second lug 6b spaced apart, with brake caliper mounting holes 6c on the first lug 6a and the second lug 6b respectively.

[0022] Because the lower control connecting arm is arranged in a downward inclined direction, when the vehicle travels over uneven road surfaces, a vertical impact load F from the road surface acts on the arm. According to the principle of force decomposition, this vertical load is decomposed on the lower control connecting arm into an axial component F∥=F·cosθ along the arm length and a lateral component F⊥=F·sinθ perpendicular to the arm length. Among them, the lateral component F⊥ generates an additional bending moment M between the two spaced first mounting holes 3a. This bending moment makes the area between the two mounting holes the section where the alternating tensile and compressive stresses are most intense, and fatigue cracks are very likely to initiate in this area.

[0023] In existing structures without arc-shaped grooves, the lower surface between the two first mounting holes 3a is typically a plane or a simple transition surface. Stress lines in this area are transmitted in an approximately straight line, leading to stress concentration at the hole edges. This application addresses this by providing an arc-shaped groove on the lower surface between the two first mounting holes 3a, changing the original planar transition to a curved transition. This forces the stress transmission path to redistribute along the tangential direction of the arc. The stress lines extend from the hole edges towards the curved surface of the arc-shaped groove, dispersing peak stress over a larger curved area, thereby effectively reducing the stress concentration factor at the hole edges and the root of the bifurcation.

[0024] Therefore, the lower surface of the lower control connecting arm has an arc-shaped groove located between the two first mounting holes 3a. The radius of curvature of the arc-shaped groove is R, and the tilt angle of the lower control connecting arm is θ; where R ≥ λ⋅W⋅sin 2 θ, 1≤λ≤2, W is the thickness of the lower control connecting arm at the center of the arc groove. In the above force analysis, the bending moment M generated by the transverse component F⊥ is proportional to sinθ, and the stress concentration caused by this bending moment is closely related to the structural thickness W: the larger the thickness W, the larger the section bending modulus, but the higher the absolute stress value in the stress concentration area, requiring a larger radius of curvature to disperse the stress. Through mechanical derivation, it can be seen that to ensure the arc groove has sufficient stress dispersion capability, its radius of curvature R should be at least equal to W·sinθ. 2 θ is on the same order of magnitude. Where, sin 2 The θ term comprehensively reflects the amplification effect of the tilt angle on the bending moment effect—when the tilt angle θ approaches 45°, sin 2 When θ approaches 1, the bending moment effect generated by the lateral component of the force is most significant, and the required stress dispersion radius of curvature is also the largest; when θ approaches 0° or 90°, sin 2 As θ approaches 0, the bending moment effect weakens, but considering the typical arrangement angle of the steering knuckle in engineering practice, sin 2The θ term ensures the applicability of the relation within the commonly used angle range. λ is a correction coefficient, and its value range of 1≤λ≤2 is based on the following: when λ is 1, the relation gives the theoretical lower limit value that meets the basic stress dispersion requirements, applicable to conventional urban road conditions; when λ is 2, it provides sufficient safety margin for harsh conditions (such as off-road surfaces, emergency braking, and other high-frequency, high-amplitude loads), while avoiding excessively large R values ​​that would weaken structural strength and increase processing costs. W is defined as the thickness of the lower control connecting arm at the center of the arc groove. This parameter is directly related to the local stiffness of the stress concentration area. Using W as a reference dimension ensures that the radius of curvature R matches the local structural dimensions, avoiding the radius of curvature being too large or too small relative to the wall thickness.

[0025] Based on the above analysis, this invention utilizes the curved surface transition effect of the arc groove combined with R≥λ⋅W⋅sin 2 The quantitative constraint of θ reduces the peak stress in the region between the two first mounting holes 3a by 20% to 40% (compared to the uniform thickness planar structure without arc grooves), and significantly reduces the fatigue stress amplitude. Thus, while ensuring the overall lightweight design of the steering knuckle, it effectively suppresses the initiation and propagation of fatigue cracks, and greatly improves the structural strength and service life of the lower control connecting arm.

[0026] As an optional implementation, the bifurcated structure of the lower control connecting arm includes a first bifurcated end and a second bifurcated end, with two first mounting holes 3a located at the first bifurcated end and the second bifurcated end, respectively. One end of the arcuate groove is connected to the first bifurcated end, and the other end of the arcuate groove is connected to the second bifurcated end. The two ends of the arcuate groove extend to the first bifurcated end and the second bifurcated end, respectively, so that the stress-dispersing curved surface transition covers the entire bifurcated area, avoiding new stress concentration caused by geometric abrupt changes between the end of the arcuate groove and the bifurcated end. This ensures that the alternating stress from the two first mounting holes 3a can be smoothly transmitted to the root of the bifurcation along the arcuate groove, thereby further improving the fatigue reliability of the bifurcated structure under complex loads.

[0027] As an optional implementation, the upper surface of the lower control connecting arm is further provided with reinforcing ribs. The addition of reinforcing ribs to the upper surface of the lower control connecting arm forms an asymmetrical composite reinforcement structure with the arcuate grooves on the lower surface. The upper surface reinforcing ribs primarily bear tensile stress and increase the flexural modulus of the cross-section, creating a synergistic effect with the stress dispersion effect of the arcuate grooves on the lower surface. This effectively improves the flexural stiffness and ultimate bearing capacity of the lower control connecting arm without significantly increasing its overall wall thickness and weight.

[0028] As an optional implementation, the first lug 6a and the second lug 6b have raised positioning steps on the side facing the wheel hub bearing mounting hole 2 for radial positioning engagement with the brake caliper bracket; and the first lug 6a and the second lug 6b are arranged in a figure-eight shape. The raised positioning steps on the inner sides of the first lug 6a and the second lug 6b form a radial positioning engagement with the inner hole or end face of the brake caliper bracket, limiting the radial displacement of the brake caliper during vehicle braking and avoiding brake vibration and uneven wear caused by radial clearance; at the same time, the figure-eight arrangement of the two lugs creates a favorable angle relationship between the line connecting the brake caliper mounting hole 6c and the direction of the braking torque, improving the installation rigidity and torsional resistance of the brake caliper and suppressing circumferential movement during emergency braking.

[0029] As an optional implementation, the steering knuckle body 1 is further provided with a sensor mounting boss 8, which is located below the wheel hub bearing mounting hole 2 and close to the steering tie rod connecting arm 4. The sensor mounting boss 8 is provided with a fastening hole 8a for fastening the wheel speed sensor. The sensor mounting boss 8 is located below the wheel hub bearing mounting hole 2 and close to the steering tie rod connecting arm 4. This arrangement makes the detection end of the wheel speed sensor close to the center of wheel rotation, shortening the air gap adjustment path between the sensor sensing surface and the gear ring, which is convenient for precise control of the air gap. At the same time, this position allows the sensor wiring harness to be naturally led out along the extension direction of the steering tie rod connecting arm 4, avoiding the motion envelope space of the lower control arm of the suspension, and reducing the risk of interference between the wiring harness and moving parts.

[0030] A second aspect of the present invention provides a hydraulic tooling for machining the steering knuckle as described above; wherein the hydraulic tooling includes a clamping base 9, a left clamping unit 10, and a right clamping unit 11. The clamp base 9 has a horizontal worktable. The left clamping unit 10 and the right clamping unit 11 are symmetrically and spaced apart on the horizontal worktable of the clamp base 9. The left clamping unit 10 and the right clamping unit 11 are used to clamp two steering knuckles respectively. The left clamping unit 10 and the right clamping unit 11 both include a positioning assembly and a hydraulic clamping assembly. The positioning assembly includes a central positioning pin 12 for engaging with the central hub bearing hole, and a plurality of bottom support columns 13 arranged around the central positioning pin 12. The top end faces of the plurality of bottom support columns 13 are respectively adapted to the contour surfaces of the lower control connecting arm, the steering tie rod connecting arm 4, the shock absorber connecting arm 5, and the brake caliper mounting part 6. The hydraulic clamping assembly includes at least two sets of hydraulic clamping mechanisms 14. The hydraulic clamping mechanisms 14 are respectively arranged around the central positioning pin 12 and are used to clamp and fix the ends of each arm of the steering knuckle to the bottom support columns 13 under hydraulic drive. The hydraulic fixture employs a symmetrically arranged left clamping unit 10 and right clamping unit 11. Each clamping unit is centered by a central positioning pin 12 and a wheel hub bearing mounting hole 2 of the steering knuckle. The top contour surface of the bottom support column 13 surrounding the central positioning pin 12 is adapted to the bottom contour surface of the lower control connecting arm, steering tie rod connecting arm 4, shock absorber connecting arm 5, and brake caliper mounting part 6, respectively, to achieve multi-point contour support. The hydraulic clamping mechanism 14 applies clamping force from above the ends of each arm, forming a clamping system of "multi-point contour support at the bottom and local clamping at the top", which effectively resists the vibration and displacement caused by the cutting force during processing and ensures dimensional consistency when the left and right dual workstations are processed simultaneously.

[0031] As an optional implementation, the hydraulic clamping assembly includes a hydraulic cylinder 14a and a clamping arm 14b. The hydraulic cylinder 14a is installed inside the clamp base 9; one end of the clamping arm 14b is connected to the piston rod of the hydraulic cylinder 14a, and the other end is provided with a clamping block 14c; when the hydraulic cylinder 14a is activated, the clamping block 14c is respectively clamped above the shock absorber connecting arm 5, the steering tie rod connecting arm 4, and the lower control connecting arm of the steering knuckle. The clamping arm 14b in the hydraulic clamping assembly is driven by the hydraulic cylinder 14a. The clamping blocks 14c at its end are respectively arranged above the shock absorber connecting arm 5, the steering tie rod connecting arm 4 and the lower control connecting arm, so that the clamping force is directly applied to the position of each functional arm near the machining area, forming a local clamping constraint near the machining point, which significantly reduces the warping and elastic deformation of the arm end caused by the cutting force. At the same time, the hydraulically driven clamping force has stable, controllable and adjustable characteristics, which can adapt to the dimensional fluctuations caused by casting tolerances in different batches of castings, ensuring reliable clamping and no damage to the workpiece surface.

[0032] As an optional implementation, a hydraulic distribution valve block is provided on the fixture base 9 between the left clamping unit 10 and the right clamping unit 11. The hydraulic distribution valve block synchronously distributes uniform hydraulic pressure to each hydraulic cylinder 14a of the left clamping unit 10 and the right clamping unit 11 to achieve synchronous locking of the left and right dual-stations. The hydraulic distribution valve block between the left clamping unit 10 and the right clamping unit 11 synchronously distributes the pressure oil from the same hydraulic source to each hydraulic cylinder 14a of the left and right dual-stations, ensuring that the left and right steering knuckles obtain synchronous and equal clamping forces during clamping. This avoids differences in workpiece deformation or uneven distribution of machining allowance caused by inconsistent clamping forces on both sides. Simultaneous locking of the dual-stations also reduces the auxiliary time for single-piece clamping and improves processing efficiency.

[0033] As an optional implementation, the bottom support column 13 has a hemispherical or conical contact head at its top. The hemispherical or conical contact head at the top of the bottom support column 13 allows for point or narrow-band contact between the support column and the bottom surface of each arm end of the steering knuckle. Compared to traditional surface contact supports, this design can adapt to surface errors and micro-irregularities in the workpiece caused by the casting process, reducing positioning deviations caused by poor fit of the support surface. Simultaneously, the small contact area reduces the risk of contact adhesion and sticking between the support column and the workpiece, facilitating rapid removal of the workpiece after processing.

[0034] As an optional implementation, both the left clamping unit 10 and the right clamping unit 11 are provided with bottom pads 15 at their bottoms. The bottom pads 15 elevate the left clamping unit 10 and the right clamping unit 11 as a whole, forming a gap below the steering knuckle for tool clearance and chip removal. By providing bottom pads 15 at the bottoms of the left clamping unit 10 and the right clamping unit 11, the dual-station clamping structure is lifted off the horizontal worktable surface of the fixture base 9, so that a stable vertical gap is formed between the lower surface of the steering knuckle and the fixture base 9 after it is clamped and fixed. This gap firstly provides necessary axial travel clearance for machining tools (such as tools used for drilling or boring the mounting holes of the lower control connecting arm), avoiding rigid interference or collision damage between the tool tip and the fixture base 9; secondly, this gap forms a natural drainage channel for cutting chips and coolant, preventing chips from accumulating between the workpiece and the fixture, which could lead to the steering knuckle positioning surface being raised or the clamping posture shifting, while also preventing high-temperature chips from scratching the machined surface of the steering knuckle, thus ensuring the continuity of the machining process and the surface quality of the finished product.

[0035] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A steering knuckle for use in an automobile, characterized in that, include: The steering knuckle body has a hub bearing mounting hole at its center. The lower control connecting arm is located on the left side of the steering knuckle body along an inclined downward extension direction. The lower control connecting arm has a forked structure and two first mounting holes are provided at the end of the lower control connecting arm at intervals. A steering tie rod connecting arm is disposed on the rear side of the steering knuckle body along an extension direction perpendicular to the lower control connecting arm, and a second mounting hole is provided at the end of the steering tie rod connecting arm; A shock absorber connecting arm is provided on the right side of the steering knuckle body along an extension direction opposite to that of the lower control connecting arm, and a third mounting hole is provided at the end of the shock absorber connecting arm; The brake caliper mounting part is located on the front side of the shock absorber connecting arm and includes a first lug and a second lug that are spaced apart. The first lug and the second lug are respectively provided with brake caliper mounting holes. The lower surface of the lower control connecting arm has an arcuate groove located between the two first mounting holes. The radius of curvature of the arcuate groove is R, and the tilt angle of the lower control connecting arm is θ; where R ≥ λ⋅W⋅sin 2 θ, 1≤λ≤2, W is the thickness of the lower control connecting arm at the center of the arc groove.

2. The steering knuckle according to claim 1, characterized in that: The bifurcated structure of the lower control connecting arm includes a first bifurcated end and a second bifurcated end, and the two first mounting holes are respectively located at the first bifurcated end and the second bifurcated end; one end of the arcuate groove is connected to the first bifurcated end, and the other end of the arcuate groove is connected to the second bifurcated end.

3. The steering knuckle according to claim 1, characterized in that: The upper surface of the lower control connecting arm is also provided with reinforcing ribs.

4. The steering knuckle according to claim 1, characterized in that: The first and second lugs have raised positioning steps on the side facing the wheel hub bearing mounting hole for radial positioning engagement with the brake caliper bracket; and the first and second lugs are arranged in a figure-eight shape.

5. The steering knuckle according to claim 1, characterized in that: The steering knuckle body is also provided with a sensor mounting boss, which is located below the wheel hub bearing mounting hole and close to the steering tie rod connecting arm; the sensor mounting boss is provided with a fastening hole for fastening the wheel speed sensor.

6. A hydraulic tooling, characterized in that, For machining a steering knuckle as described in any one of claims 1-5; wherein the hydraulic tooling includes: A fixture base having a horizontal work surface; A left clamping unit and a right clamping unit are symmetrically and spaced apart on the horizontal worktable of the clamp base. The left clamping unit and the right clamping unit are used to clamp the two steering knuckles respectively. The left clamping unit and the right clamping unit each include a positioning component and a hydraulic clamping component. The positioning component includes a central positioning pin for engaging with the central wheel hub bearing hole, and a plurality of bottom support columns arranged around the central positioning pin. The top end faces of the plurality of bottom support columns are respectively adapted to the contour surfaces of the lower control connecting arm, the steering tie rod connecting arm, the shock absorber connecting arm, and the brake caliper mounting part. The hydraulic clamping component includes at least two sets of hydraulic clamping mechanisms. The hydraulic clamping mechanisms are respectively arranged around the central positioning pin and are used to clamp and fix the ends of each arm of the steering knuckle to the bottom support columns under hydraulic drive.

7. The hydraulic tooling according to claim 6, characterized in that: The hydraulic clamping assembly includes: A hydraulic cylinder is installed inside the fixture base; The clamping arm has one end connected to the piston rod of the hydraulic cylinder and the other end equipped with a clamping block; When the hydraulic cylinder is activated, the clamping blocks press against the upper parts of the shock absorber connecting arm, steering tie rod connecting arm, and lower control connecting arm of the steering knuckle, respectively.

8. The hydraulic tooling according to claim 6, characterized in that: A hydraulic distribution valve block is provided on the fixture base between the left clamping unit and the right clamping unit. The hydraulic distribution valve block synchronously distributes the uniform hydraulic pressure to each hydraulic cylinder of the left clamping unit and the right clamping unit to achieve synchronous locking of the left and right dual positions.

9. The hydraulic tooling according to claim 6, characterized in that: The bottom support column is provided with a hemispherical or conical contact head at its top.

10. The hydraulic tooling according to claim 6, characterized in that: Both the left and right clamping units are equipped with bottom pads at their bottoms. These bottom pads elevate the left and right clamping units as a whole, creating a gap below the steering knuckle for the machining tool to avoid and for chip removal.

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