Three-face milling process for knuckle fork ear

Abstract

The present application relates to the technical field of machining, and particularly relates to a three-surface milling machining process for a knuckle fork ear, which comprises the following steps: step one, a first milling cutter is extended into the space between two fork ears to mill the inner side surfaces of the two fork ears and the bottom surface of a disc part near the fork ears; step two, a second milling cutter is extended into the space between the two fork ears to mill the middle part of the bottom surface of the disc part; the milling area of step two is located between the milling areas of step one, and the edges of the milling areas of step two coincide with the edges of the milling areas of step one, and the distance between the coinciding edges and the inner side surfaces of the adjacent fork ears is greater than 15 mm. Through the process, the protrusion at the root of the knuckle fork ear is transferred to the middle of the disc part, so that the stress concentration at the root of the knuckle fork ear is eliminated, and the knuckle fork ear is protected from breaking.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machining, in particular to a three-surface milling process for a knuckle yoke ear. BACKGROUND

[0002] When milling the inner pin of a knuckle, the inner side of the two yoke ears is usually milled first, and then the bottom surface is milled. The finished product after milling has two processing surfaces intersecting at the junction of the yoke ear and the bottom surface (as shown in Figure 1 ), and the intersection point is the intersection point of two arcs. Because the processing limit of the milling cutter, a sharp protrusion is often generated at the intersection point. When working, the two yoke ears of the knuckle bear bending load, which acts on the protrusion part, causing stress concentration, and further causing the yoke ear of the knuckle to break. SUMMARY

[0003] The present application aims at the deficiencies of the prior art, and provides a three-surface milling process for a knuckle yoke ear. By improving the processing technology, the intersection position of the two processing surfaces is shifted from the corner of the yoke ear and the bottom surface of the knuckle to the middle of the bottom surface, thereby eliminating the stress concentration at the corner of the yoke ear and the bottom surface, and further avoiding the breakage of the yoke ear of the knuckle.

[0004] The technical solution adopted by the present application to solve the technical problem is as follows: a three-surface milling process for a knuckle yoke ear, comprising the following steps: step one, a first milling cutter is inserted between the two yoke ears for milling, the first milling cutter comprises a first cutter bar, and a cutter head is sleeved on the first cutter bar, the cutter head is provided with a cutting edge for milling the disc bottom surface near the inner side of the two yoke ears, the axis of the first cutter bar is located on the axis of the main pin hole and perpendicular to the plane of the disc, and the first cutter bar is parallel to the axis of the main pin hole, and the first cutter bar feeds along the top of the yoke ear to the disc; step two, a second milling cutter is inserted between the two yoke ears for milling, the second milling cutter comprises a second cutter bar, and a cutter head is sleeved on the second cutter bar, the cutter head is provided with a cutting edge for milling the middle part of the disc bottom surface, the position and feeding direction of the second cutter bar are the same as those of the first cutter bar, the milling area of step two is located between the milling areas of step one, and the overlapping part is greater than 15 mm from the inner side of the adjacent yoke ear.

[0005] Further, the distance from the overlapping part of the milling area of step two and the milling area of step one to the inner side of the adjacent yoke ear is greater than 25 mm.

[0006] Further, the cutter head of the first milling cutter is suspended at the middle part of the disc.

[0007] Further, in step one, the thickness of the first cutter head is less than the distance between the two fork inner side surfaces, the first cutter first processes one fork inner side surface and the disc bottom surface near the fork, and then processes the other fork inner side surface and the disc bottom surface near the fork.

[0008] Further, in step one, the thickness of the first cutter head is equal to the distance between the two fork inner side surfaces after processing, and the first cutter simultaneously processes the two fork inner side surfaces and the disc bottom surface near the fork.

[0009] Further, rough milling is first performed, the cutter simultaneously mills the two fork inner side surfaces and the disc bottom surface during rough milling, or rough milling is performed according to steps one and two; and then, fine milling is performed according to steps one and two; and a processing allowance of 0.5 mm is reserved during rough milling.

[0010] Further, a rotary disc clamp is used to fix the knuckle, the rotary disc clamp is circumferentially provided with a first station, a second station, a third station and a fourth station around a rotation center, clamping is performed at the first station, step one is performed at the second station, step two is performed at the third station, and the outer side surfaces of the two forks are milled at the fourth station.

[0011] The beneficial effects of the present application are: the knuckle fork three-surface milling process, which comprises the following steps: in step one, a first cutter is inserted between the two forks to mill, the first cutter comprises a first cutter bar, the first cutter bar is sleeved with a cutter head, the cutter head is provided with cutter edges for milling the two fork inner side surfaces and the disc bottom surface near the fork, the axis of the first cutter bar is located on the axis of the main pin hole and perpendicular to the plane of the disc part, and the first cutter bar is parallel to the axis of the main pin hole, and the first cutter bar feeds along the top of the fork to the disc part; in step two, a second cutter is inserted between the two forks to mill, the second cutter comprises a second cutter bar, the second cutter bar is sleeved with a cutter head, the cutter head is provided with cutter edges for milling the middle part of the disc bottom surface, the position and feeding direction of the second cutter bar are the same as those of the first cutter bar, the milling area of step two is located between the milling areas of step one, and the edges coincide, and the distance between the coinciding part and the adjacent fork inner side surface is greater than 15 mm. Through the process, the protrusion at the root of the knuckle fork is transferred to the middle of the disc part, thereby eliminating the stress concentration at the root of the knuckle fork and protecting the fork from breaking. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a schematic diagram of the protrusion at the root of the knuckle fork generated during the processing of the prior art;

[0013] Figure 2 is a schematic diagram of the processing of step one;

[0014] Figure 3 is a schematic diagram of the processing of step two;

[0015] Figure 4 This is a schematic diagram of the machining process for the outer side of the two forked ears;

[0016] Figure 5 , Figure 6 This is a schematic diagram of rough milling of the inner side of the two forked ears and the bottom surface of the disc;

[0017] Figure 7 This is a schematic diagram of a turntable fixture.

[0018] Explanation of reference numerals in the attached figures:

[0019] 1 – First milling cutter, 11 – First tool holder, 2 – Second milling cutter, 21 – Second tool holder, 3 – Turntable fixture. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0021] like Figures 2-7 As shown, the three-sided milling process of the steering knuckle fork lug in this embodiment includes the following steps: Step 1, inserting a first milling cutter 1 between the two fork lugs for milling. The first milling cutter 1 includes a first cutter bar 11, which is fitted with a cutter disc. The cutter disc is provided with a cutting edge for milling the inner sides of the two fork lugs and the bottom surface of the disc near the fork lugs. The axis of the first cutter bar 11 is located in a plane that encompasses the axis of the kingpin hole and is perpendicular to the disc. The first cutter bar 11 is parallel to the axis of the kingpin hole. The first cutter bar 11 feeds along the top of the fork lugs toward the disc. Step 2, inserting a second milling cutter 2 between the two fork lugs for milling. The second milling cutter 2 includes a second cutter bar 21, which is fitted with a cutter disc. The cutter disc is provided with a cutting edge for milling the middle part of the bottom surface of the disc. The position and feed direction of the second cutter bar 21 are the same as those of the first cutter bar 11. The milling area in step 2 is located between the milling areas in step 1 and overlaps at the edge. This causes the milled surfaces that were originally located at the root of the fork lug to intersect and protrude towards the center of the disc. In order to ensure that the stress concentration area is far enough away from the root of the fork lug, the distance between the overlapping point and the inner side of the nearby fork lug is greater than 25mm.

[0022] This invention is mainly applied to the machining of the inner side of the steering knuckle fork lugs, but it can also be applied to the machining of other similar components. This embodiment uses the machining of the steering knuckle fork lugs as an example. The steering knuckle includes an axle for mounting the wheel hub. A disc is provided at the top of the axle, and two fork lugs, one long and one short, are provided at both ends of the disc. The disc mentioned in this text refers to the disc at the top of the axle. The objects of machining in this embodiment are the inner and outer sides of the two fork lugs, as well as the side of the disc facing the fork lugs (also called the bottom surface of the disc).

[0023] The first milling cutter 1 is a custom milling cutter, the first cutter bar 11 is parallel to the main pin hole axis (i.e. the axis of the hole passing through the two fork ears), and the first cutter bar 11 rotates while feeding towards the disc part at the top of the fork ear, so as to mill the inner side surfaces of the two fork ears and the bottom surface of the disc part near the fork ear by the cutter disc of the rotating first milling cutter 1. In order to avoid milling the middle part of the disc part in step one, the middle part of the cutter disc of the first milling cutter 1 is suspended. This suspension can have the following structures: the cutter disc of the first milling cutter 1 is a relatively thick integral cutter disc, and the middle part is suspended; or the cutter disc of the first milling cutter 1 is composed of two coaxial cutter discs, and the two cutter discs are suspended.

[0024] The thickness of the cutter disc of the first milling cutter 1 can be smaller than the distance between the inner side surfaces of the two fork ears, so that when milling, the first milling cutter 1 first mills the inner side surface of one fork ear and the bottom surface of the disc part near the fork ear, then translates along the axis of the first cutter bar 11, and then mills the inner side surface of the other fork ear and the bottom surface of the disc part near the fork ear.

[0025] The thickness of the cutter disc of the first milling cutter 1 can also be equal to the distance between the inner side surfaces of the two fork ears after processing, so that when milling, the first milling cutter 1 simultaneously mills the inner side surfaces of the two fork ears and the bottom surface of the disc part near the two fork ears.

[0026] In order to improve the processing efficiency and accuracy, the embodiment further provides a rotary table clamp 3 for fixing the knuckle, and the rotary table clamp 3 is circumferentially provided with a first station, a second station, a third station and a fourth station. The clamping operation is performed at the first station, the processing of step one is performed at the second station, the processing of step two is performed at the third station, and the outer side surfaces of the two fork ears are milled at the fourth station.

[0027] The knuckle has a large excess after forging, and generally needs to be rough milled and then fine milled. According to different forging methods of the knuckle, the following processes can be arranged for processing. The forging method of the knuckle has vertical forging and horizontal forging. In vertical forging, the wheel shaft is at the bottom and the two fork ears are at the top. In this forging, the metal excess of the inner side surfaces of the two fork ears is not much. In horizontal forging, the wheel shaft and the two fork ears are horizontally placed and are located on the same plane. In this forging, the inner side surfaces of the two fork ears, especially the inner side surface of the short ear, have more metal.

[0028] For vertical forging, the following processes are arranged: simultaneously rough milling the inner side surfaces of the two fork ears and the bottom surface of the disc part, leaving a 0.5mm processing excess; then fine milling the inner side surfaces of the two fork ears and the bottom surface of the disc part according to steps one and two; and finally milling the outer side surfaces of the two fork ears.

[0029] For horizontal forging, the following procedures are arranged: rough milling of the inner side surfaces of the two prongs and the bottom surface of the adjacent disc part according to step one using a rough milling cutter with a thickness less than the distance between the inner side surfaces of the two prongs, and milling off excessive metal; then simultaneously milling the inner side surfaces of the two prongs and the bottom surface of the disc part using a cutter disc with a thickness equal to the distance between the inner side surfaces of the two prongs after rough processing, leaving a 0.5mm machining allowance; the third step is to fine mill the inner side surfaces of the two prongs and the bottom surface of the disc part according to step one and step two; and finally milling the outer side surfaces of the two prongs. The first two rough milling steps can also be directly milled to leave only a 0.5mm machining allowance when rough milling the inner side surfaces of the two prongs and the bottom surface of the adjacent disc part in the first step, and then only milling the middle part of the bottom surface of the disc part in the second step, leaving a 0.5mm machining allowance.

[0030] When milling the outer side surfaces of the two prongs, a single cutter bar is used to hold two cutter discs, and the same position and feed direction are used for simultaneous milling according to step one.

[0031] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A three-surface machining process for knuckle fork ears, characterized in that: Step one, the first milling cutter (1) is inserted between the two fork ears for milling, the first milling cutter (1) includes a first cutter bar (11), the first cutter bar (11) is sleeved with a cutter head, the cutter head is provided with a cutter edge for milling the disc bottom surface near the inner side of the two fork ears, the axis of the first cutter bar (11) is located in the containing kingpin hole axis and perpendicular to the plane of the disc, and the first cutter bar (11) is parallel to the kingpin hole axis, and the first cutter bar (11) feeds along the disc to the top of the fork ear; step two, the second milling cutter (2) is inserted between the two fork ears for milling, the second milling cutter (2) includes a second cutter bar (21), the second cutter bar (21) is sleeved with a cutter head, the cutter head is provided with a cutter edge for milling the middle part of the disc bottom surface, the position and feeding direction of the second cutter bar (21) are the same as those of the first cutter bar (11), the milling area of step two is located between the milling areas of step one, and the edge coincides, and the distance between the coincident part and the inner side surface of the adjacent fork ear is greater than 15mm; in step one, the thickness of the cutter head of the first milling cutter (1) is less than the distance between the inner side surfaces of the two fork ears, the first milling cutter (1) processes one fork ear inner side surface and the disc bottom surface near the fork ear first, and then processes the other fork ear inner side surface and the disc bottom surface near the fork ear.

2. The knuckle yoke tri-milling process of claim 1, wherein: The distance between the coincident part of the milling area of step two and the inner side surface of the adjacent fork ear is greater than 25mm.

3. The knuckle yoke tri-milling process of claim 1, wherein: The cutter head of the first milling cutter (1) is suspended at the middle part of the disc.

4. The knuckle yoke tri-milling process of claim 1, wherein: In step one, the thickness of the cutter head of the first milling cutter (1) is equal to the distance between the processed inner side surfaces of the two fork ears, and the first milling cutter (1) processes the inner side surfaces of the two fork ears and the disc bottom surface near the fork ears at the same time.

5. The knuckle yoke tri-milling process of claim 1, wherein: First, rough milling, when rough milling, the milling cutter mills the inner side surfaces of the two fork ears and the disc bottom surface at the same time, or rough milling is performed according to steps one and two; then, fine milling is performed according to steps one and two; when rough milling, a processing allowance of 0.5mm is reserved.

6. The knuckle yoke tri-milling process of claim 1, wherein: The knuckle is fixed by using a rotary disc clamp (3), the rotary disc clamp (3) is provided with a first station, a second station, a third station and a fourth station around the rotation center circle, the clamping operation is performed at the first station, the processing of step one is performed at the second station, the processing of step two is performed at the third station, and the outer side surfaces of the two fork ears are milled at the fourth station.

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