A machining process for forging center hole steering knuckles

Abstract

This invention relates to a machining process for a forged center hole steering knuckle, comprising the following steps: S1, screening blanks, measuring the deformation of the rod, and screening out unqualified blanks whose deformation exceeds a predetermined threshold; S2, determining the positioning datum, rough machining the outer wall of the rod and the end face of the buckle plate of the unqualified blank, using the rod and the end face of the buckle plate as the positioning datum; S3, determining the machining datum, based on the positioning datum, milling a shaft end chamfer at a predetermined angle on the end face of the journal, wherein the center of the chamfer has a certain offset in the opposite direction of the deformation, using the shaft end chamfer and the center hole at the fork lug as the machining datum; S4, machining the finished product, performing semi-finish turning and finish turning operations on the rod and the buckle plate based on the machining datum, and machining off the shaft end chamfer after completion; This process can salvage problematic blanks with deformed or non-perpendicular rods, effectively avoiding cost waste and reducing losses.

Description

Technical Field

[0001] This invention relates to the field of automotive parts processing technology, specifically to a processing technology for forging a steering knuckle with a center hole. Background Technology

[0002] During driving, a car frequently changes its direction of travel (steering). Typically, when a vehicle turns, the driver applies a steering torque to the steering wheel. This torque travels through the steering shaft, drive shaft, and steering gear. After being amplified by the steering gear, the torque is transmitted to the steering rocker arm, then through the steering tie rod to the steering knuckle and the steering knuckle arm on the steering knuckle, and finally to the wheel hub, causing the wheel to deflect. The steering knuckle arm is the final stage of force transmission in the steering transmission system. In current automotive design, steering knuckles are generally forged as a single piece, undergoing multiple processes such as heating, pre-forging, molding, shaping, and trimming to complete the blanking. They are then machined. The lugs, disc (with a locking plate around the rod), and rod of the steering knuckle are a single, integral structure, while the steering knuckle arm is connected to the steering knuckle after machining using bolts or ball joints.

[0003] Currently, there is a new type of steering knuckle on the market. Its blank is made using inclined forging technology, and its rod center hole is formed by forging. Due to the complex shape of the product and the fact that it is a new product, there is no historical experience to draw on in the forging and machining process. During the forging of the center hole, the rod often bends or deforms, or the rod axis is not perpendicular to the disc. This leads to black skin on the disc groove and uneven wall thickness of the locking platform during the subsequent semi-finish machining of the rod and disc, resulting in material scrap and cost loss. Summary of the Invention

[0004] Based on the above description, the present invention provides a machining process for forging a center hole steering knuckle to solve the above problems.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] A machining process for a forged center hole steering knuckle includes the following steps:

[0007] S1. Screen the blanks, measure the deformation of the rod, and screen out unqualified blanks whose deformation exceeds the predetermined threshold.

[0008] S2. Determine the positioning reference. Rough machine the outer wall of the rod and the end face of the buckle platform of the unqualified blank, and use the rod and the end face of the buckle platform as the positioning reference.

[0009] S3. Determine the machining reference. Based on the positioning reference, mill a shaft end chamfer at a predetermined angle on the end face of the journal. The chamfer center has a certain offset in the opposite direction of the deformation amount. The shaft end chamfer and the center hole at the fork lug are used as the machining reference.

[0010] S4. Process the finished product. Based on the processing benchmark, perform semi-finish turning and finish turning processes on the rod and the buckle plate. After completion, remove the chamfer at the shaft end.

[0011] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0012] The machining process for the forged center hole steering knuckle provided in this application firstly identifies blanks that are conventionally defined as defective by measuring the deformation of the rod. Then, a new positioning datum is made. Based on the positioning datum, a chamfer is made on the shaft end in the opposite direction of the deformation to compensate for the deformation. Then, semi-finish turning and finish turning processes are performed using the shaft end chamfer and the center hole at the fork lug as machining datums. Finally, the shaft end chamfer is removed. In this way, defective blanks with deformed or non-perpendicular rods can be salvaged, effectively avoiding cost waste and reducing losses.

[0013] Based on the above technical solution, the present invention can be further improved as follows.

[0014] Furthermore, the process of screening out unqualified blanks whose deformation exceeds a predetermined threshold includes:

[0015] The machine tool top is used to locate the center hole of the rod, and a lever dial indicator is used to measure the deviation distance between the two ends of the rod on the end face of the disc, which is the deformation amount. Unqualified blanks with deformation amounts exceeding the predetermined threshold are screened out.

[0016] Furthermore, the magnitude of the offset is smaller than the magnitude of the deformation threshold.

[0017] Furthermore, the deformation threshold is 3 mm.

[0018] Furthermore, the offset is 2 to 2.5 mm.

[0019] Furthermore, the predetermined angle of the chamfer at the shaft end is 2×45°.

[0020] Furthermore, it also includes: for blanks with deformation below a predetermined threshold, grinding the positioning boss inside the center hole of the rod and then machining it. Attached Figure Description

[0021] Figure 1 A schematic diagram illustrating the steps of a forging center hole steering knuckle provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of the forged center hole steering knuckle involved in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the fixture for the steering knuckle blank involved in an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the clamping and positioning of the steering knuckle blank involved in an embodiment of the present invention. Detailed Implementation

[0025] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0027] It is understood that spatial relation terms such as "below," "under," "below," "below," "above," "above," etc., can be used here to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as "below" or "below" of the other element or feature will be oriented "above" the other element or feature. Therefore, the exemplary terms "below" and "below" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90° or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0028] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0029] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0030] This application provides a machining process for forging a center hole steering knuckle, such as... Figure 1As shown, it includes the following steps:

[0031] S1. Screen the blanks, measure the deformation of the rod, and screen out unqualified blanks whose deformation exceeds the predetermined threshold.

[0032] In this application, the amount of deformation refers to the deviation distance between the two ends of the rod on the end face of the disc. The greater the amount of deformation, the greater the deformation of the rod or the greater the degree to which the rod is not perpendicular to the disc. Therefore, the degree of defect of the rod of the blank can be determined by measuring the amount of deformation.

[0033] The predetermined threshold is equivalent to the critical point of the deformation of the blank rod. When the deformation of the blank rod exceeds the predetermined threshold, the blank can be defined as a defective blank, that is, a blank that needs to be salvaged in this application.

[0034] In the embodiments of this application, the defective blanks with deformation exceeding a predetermined threshold are screened out as follows: the machine tool top is used to locate the center hole of the rod, and the deformation of the rod is measured using a lever dial indicator to screen out defective blanks with deformation exceeding a predetermined threshold.

[0035] For example, for a certain H6 type forged center hole steering knuckle used for assembly, the predetermined threshold for deformation during the production process is 3mm. That is, blanks with a deformation of more than 3mm are generally identified as problematic parts, which are generally considered as scrapped blanks.

[0036] After identifying the above-mentioned unqualified blanks, proceed to the next step:

[0037] S2. Determine the positioning reference. Rough-machine the outer wall of the rod and the end face of the buckle platform of the unqualified blank, and use the rod and the end face of the buckle platform as the positioning reference.

[0038] like Figure 2 As shown, the locking platform 10 generally refers to an annular boss on the end face of the disc 20. The middle part of the locking platform 10 is the rod 30. In the embodiment of this application, the outer wall of the rod 30 and the end face of the locking platform 10 are rough-machined to meet the requirements of the blank, and the rod 30 and the end face of the locking platform 10 are used as positioning references.

[0039] In one specific embodiment, the jig fixture 100 for the steering knuckle blank is as follows: Figure 3 As shown, the machining and assembly are as follows Figure 4 As shown, the rod 30 is inserted into the middle through hole 10a of the fixture 100 as a positioning reference, and the end face of the locking platform 10 and the side of the fixture 100 abut as another positioning reference, which can realize the positioning of the defective blank.

[0040] S3. Determine the machining datum. Based on the positioning datum, mill a shaft end chamfer at a predetermined angle on the end face of the journal. The center of the chamfer has a certain offset in the opposite direction of the deformation amount. The shaft end chamfer and the center hole at the fork lug are used as the machining datum.

[0041] Taking the H6 type steering knuckle with arm assembled above as an example, in order to compensate for the deformation of the rod, a 2×45° end chamfer is milled on the end face of the journal. The center of the end chamfer is offset by 2 to 2.5 mm in the opposite direction of the deformation.

[0042] S4. Finished product: Based on the above processing benchmarks, the rod 30 and the buckle plate 10 are semi-finished and finished. After completion, the shaft end chamfer is removed to form the finished product with the arm steering knuckle.

[0043] For blanks with small deformation, traditional processing methods can lead to inconvenience and inaccurate positioning. Therefore, this application further proposes that for blanks with deformation below a predetermined threshold, the positioning boss in the center hole of the rod is ground and then machined, which can effectively reduce the occurrence of the above problems.

[0044] The machining process for the forged center hole steering knuckle provided in this application firstly identifies blanks that are conventionally defined as defective by measuring the deformation of the rod. Then, a new positioning datum is made. Based on the positioning datum, a chamfer is made on the shaft end in the opposite direction of the deformation to compensate for the deformation. Then, semi-finish turning and finish turning processes are performed using the shaft end chamfer and the center hole at the fork lug as machining datums. Finally, the shaft end chamfer is removed. In this way, defective blanks with deformed or non-perpendicular rods can be salvaged, effectively avoiding cost waste and reducing losses.

[0045] 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 machining process for a forged center hole steering knuckle, comprising the following steps: S1. Screening blanks, measuring the deformation of the rod, and screening out unqualified blanks whose deformation exceeds a predetermined threshold; S2. Determining the positioning datum, rough turning the outer wall of the rod and the end face of the buckle platform of the unqualified blank, using the rod and the end face of the buckle platform as the positioning datum; S3. Determining the machining datum, based on the positioning datum, milling a shaft end chamfer of a predetermined angle on the end face of the journal, wherein the center of the chamfer has a certain offset in the opposite direction of the deformation, using the shaft end chamfer and the center hole at the fork lug as the machining datum; S4. Machining the finished product, performing semi-finish turning and finish turning operations on the rod and the buckle platform based on the machining datum, and machining off the shaft end chamfer after completion; for blanks whose deformation is below the predetermined threshold, grinding the positioning boss in the center hole of the rod, and then machining.

2. The machining process of the forged center hole steering knuckle according to claim 1, characterized in that, The process of screening out unqualified blanks with deformation exceeding a predetermined threshold includes: using the top of the machine tool to locate the center hole of the rod, and using a lever dial indicator to measure the deviation distance between the two ends of the rod on the end face of the disc, which is the deformation amount, and screening out unqualified blanks with deformation exceeding a predetermined threshold.

3. The machining process of the forged center hole steering knuckle according to claim 1, characterized in that, The offset is smaller than the deformation threshold.

4. The machining process of the forged center hole steering knuckle according to claim 3, characterized in that, The predetermined threshold is 3mm.

5. The machining process of the forged center hole steering knuckle according to claim 4, characterized in that, The offset is 2 to 2.5 mm.

6. The machining process of the forged center hole steering knuckle according to claim 1, characterized in that, The predetermined angle of the chamfer at the shaft end is 2×45°.

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