Aviation bearing inner raceway metal streamline symmetrical and uniform distribution automatic forging process method

Abstract

The invention discloses an aircraft bearing inner raceway metal streamline symmetrical and uniform distribution automatic forging process method which comprises the steps that a, a two-station punch is adopted, specifically, a spure spreader punch punches and shunts, metal fibers in an inner hole are kept complete, and the defects of cutting, bending and the like are avoided; the inner wall of a second-station die cavity is designed to be in a big-end-up cone shape and is consistent with the punch in direction; c, chambering and via hole shaping: chambering by using a chambering punch until the outer diameter is parallel and has no taper, and shaping an inner hole by using a small-angle via hole punch according to the design size to realize that the inner hole is parallel to the outer diameter; and d, ring rolling is conducted, specifically, a straight inner hole is subjected to ring rolling, the ring blank is stably positioned on the mandrel, and uniform and symmetrical deformation is achieved on the two sides of an inner hole channel in the rolling and chambering forming process. The method has the advantages that the quality problems of non-uniform distribution of metal flow lines on the two sides of the channel and inconsistent density state are solved, and economic loss caused by waste products formed by non-uniform distribution of the metal flow lines of the channel in the bearing ring forge piece is avoided.

Description

Technical Field

[0001] The invention relates to a forging method for an aviation bearing, in particular to an automated forging process method for inner raceway metal streamlines. Background Art

[0002] Aviation bearings are mainly used for the operation of various transmission parts of aircraft engines. They are special bearings for aviation weapons and equipment or civil aircraft. The main shaft bearings operate under harsh working conditions of high temperature, high pressure and high speed. They need to achieve high reliability, long life and light weight to meet the ever-increasing technical indicators of modern aircraft. The main shaft bearing is one of the largest components that affect the quality of aircraft engines, and its quality is particularly important for the engine. The metal streamline distribution of the main shaft bearing, especially the distribution of the metal streamline of the raceway, will have a great impact on the performance of the bearing, and even affect the safety of aviation operations in severe cases. Due to the imperfect process design and blank rolling technology in the early stage, the density and uniformity of the metal streamline distribution of the raceway in the main shaft bearing did not meet the expected design requirements. The metal streamline processing process of the raceway surface often cuts out the exposed head, forming a stress source, resulting in early cracking of the bearing raceway surface and other damage defects, which seriously affects the high life and flight safety of the aircraft engine.

[0003] The reasons for the uneven distribution of metal streamlines in the spindle bearing are analyzed. The results show that (1) the design of the automatic line blanking mold is unreasonable. After the two-station ring blank is formed, the inner hole is conical and the outer diameter is a conventional straight cylinder. The metal streamline distribution is dense at the top and sparse at the bottom, and the distribution is uneven; (2) After the hole is expanded and shaped, the outer diameter of the ring blank is conical, which is not parallel to the straight part of the inner hole. During the rolling process, the high point of the conical outer diameter of the ring blank contacts the rolling wheel in advance, causing the ring blank to tilt and become unstable during rolling. When the inner hole groove is formed, the two sides cannot be extruded at the same time, resulting in uneven and asymmetric metal density and metal streamline distribution on both sides of the groove. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an automated forging process method for symmetrical and uniform distribution of metal streamlines in the inner raceway of aviation bearings, so as to solve the quality problems of asymmetrical and uneven distribution of metal streamlines in the inner groove of bearing ring forgings, and exposed streamlines on the bearing raceway surface after processing. In order to achieve the above technical goals, the present invention adopts the following design scheme, and the specific steps are as follows: an automated forging process method for symmetrical and uniform distribution of metal streamlines in the inner raceway of aviation bearings, the automated forging production line is composed of two presses and six stations, namely, the first station is for pressing cakes, the second station is for punching and diverting, the third station is for turning the workpiece over, cutting the bottom and expanding the hole, the fourth station is for expanding the hole twice, once on the front and back, the fifth station is for shaping with a straight punch, and the sixth station is for flattening;

[0005] a. Two-station punch: The diverter cone punch punches and diverts the flow, keeping the metal fiber in the inner hole intact without defects such as cutting and bending;

[0006] b. Two-station mold: The inner wall of the two-station mold cavity is designed to be tapered with a large top and a small bottom, which is consistent with the direction of the punch;

[0007] c. Hole expansion and through-hole shaping: Use hole expansion punch to expand the hole until it is parallel to the outer diameter without taper, and then use small-angle through-hole punch to shape the inner hole according to the designed size to achieve parallelism between the inner hole and the outer diameter;

[0008] d. Rolling: The straight inner hole is rolled and expanded. The ring blank is positioned stably on the mandrel. During the rolling and expanding process, uniform and symmetrical deformation is achieved on both sides of the inner hole channel.

[0009] Preferably, the inner wall of the two-station mold cavity has a slope of 5°, and the diverter cone punch has a slope of 14°, and the two are inclined in the same direction.

[0010] After the ring blank is formed, it is transferred by the robot to the third station for bottom cutting and then returned to the furnace for heating; at the fourth station, the inner hole is expanded to the process size and the outer diameter is parallel and without taper. The size and depth of the expanded holes at both ends of the inner hole are symmetrical. At the fifth station, a small-angle through-hole punch is used to shape the inner hole according to the design size. The straight part of the inner hole is parallel to the outer diameter. At the sixth station, the upper and lower end surfaces of the flat width are parallel.

[0011] The rolling method is as follows: the ring blank is hung on a core shaft with a protruding groove, and is positioned closely with the shaft disc as a reference. The rolling wheel is in direct contact with the outer diameter of the ring blank to roll and expand the ring, and the inner groove is evenly formed.

[0012] The advantages of the present invention are as follows: the low-magnification microstructure of the aviation bearing ring forging forged by the present invention is tested and the metal streamlines are symmetrically and evenly distributed along the channel, which solves the quality problems of uneven distribution of metal streamlines on both sides of the channel and inconsistent density, and meets the requirements of the MMS50003 standard and the technical and usage requirements of the product, prolongs the service life of the bearing, and avoids the economic loss caused by waste due to the uneven distribution of metal streamlines in the channel of the bearing ring forging. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the two-station punch and the lower die;

[0014] Figure 2 It is a schematic diagram of hole expansion;

[0015] Figure 3 For attachment Figure 1 Ring blank punching metal streamline Deform simulation state;

[0016] Figure 4 Simulate the state of metal streamline Deform for ring blank expansion and through-hole shaping;

[0017] Figure 5-1 This is the distribution state diagram of metal streamlines in the Deform simulation channel rolling;

[0018] Figure 5-2 This is the temperature field state diagram of Deform simulation channel rolling;

[0019] Figure 6 This is a diagram of an inner channel aviation bearing ring forging of the present invention;

[0020] Figure 7 This is a grain size photo of the product of the present invention;

[0021] Figure 8 This is the carbide distribution diagram of the product of the present invention;

[0022] Fig. 9 This is a metal flow line photo of the product of the present invention;

[0023] Fig.10 It is a microscopic pore photograph of the product of the present invention;

[0024] Fig.11 This is a photo of the fracture structure of the product of the present invention;

[0025] In the figure, 1 is a diverter cone punch, 2 is the inner wall of the two-station die cavity, 3 is a ring blank, 4 is an upper die handle, and 6 is a lower die. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the accompanying drawings.

[0027] The specific steps of the present invention are as follows: an automated forging process method for symmetrically and evenly distributing metal streamlines in the inner raceway of an aviation bearing, wherein the automated forging production line is composed of two presses and six stations, wherein the first station is for pressing a cake, the second station is for punching and diverting, the third station is for turning the workpiece over, cutting the bottom and expanding the hole, the fourth station is for expanding the hole twice, once for the front and back, the fifth station is for shaping with a straight punch, and the sixth station is for flattening the width;

[0028] a. Press the ring at station 1, and the robot will transfer to station 2. The diverter cone punch will punch holes and divert the flow. The metal fiber in the inner hole is intact without defects such as cutting or bending. The inner wall of the mold cavity at station 2 is designed as a conical structure with a 5° slope in the same direction as the 14° slope of the diverter cone punch. After the ring blank is formed, it will be transferred to station 3 by the robot to cut the bottom and return to the furnace for heating; the slope here refers to the angle with the vertical direction, such as Figure 1 shown.

[0029] b. The inner hole is expanded to the process size at the 4th station and the outer diameter is parallel without taper. The size and depth of the expansion holes at both ends of the inner hole are symmetrical. The inner hole is shaped by punching at a small angle according to the design size at the 5th station. The straight part of the inner hole is parallel to the outer diameter. The upper and lower end surfaces of the flat width are parallel at the 6th station.

[0030] c. Rolling: The ring blank is hung on the core shaft with protruding grooves and is positioned closely with the shaft disc as the reference. The rolling wheel is in full contact with the outer diameter of the ring blank longitudinally to roll the ring and evenly form the inner groove.

[0031] d. The present invention firstly performs precision machining and inspection on the automatic line forging die to ensure that the die size accuracy meets the design requirements and ensure the forging quality of the ring blank.

[0032] The punch of the two-station blank making die is designed to have a large upper and lower diverter cone structure. The purpose is to avoid damage to the metal streamlines in the inner hole during the punching process, bending deformation, and inconsistent density distribution of the metal streamlines of the ring blank after punching. To this end, through equivalent volume calculation and Deform simulation verification, the inner diameter of the ring blank die is designed to be consistent with the angle direction of the punch diverter cone to compensate for the uneven density distribution of the metal streamlines of the cake blank caused by the diverter cone punching. Figure 3 shown.

[0033] By designing and verifying the forming process of the hole expansion process, the ring blank with a straight inner hole in the channel area parallel to the outer diameter is obtained after hole expansion and hole shaping. Figure 4 .

[0034] The straight area of ​​the inner hole groove of the ring blank is parallel to the outer diameter and perpendicular to the two end surfaces. It is hung on the mandrel with groove forming protrusions and positioned by the shaft disc. When the rolling wheel rolls and expands the hole, stable forming is achieved. The metal on both sides of the groove is symmetrically and evenly deformed, and its metal streamlines are symmetrically and evenly distributed along the raceway. The forming process of the rolling expansion process is designed and Deform simulation verification is verified as shown in the attached Figure 5-1 and attached Figure 5-2 , which solves the quality problem of asymmetric and uneven distribution of metal streamlines in the raceway, and avoids the exposure of metal streamlines after raceway turning, forming potential invisible quality defects on the raceway surface.

[0035] In order to achieve the design goal, a number of billet making and rolling process plans were formulated. After testing, inspection and process optimization design, and verified by Deform simulation, a complete and reasonable ring billet forming and rolling plan was finally formed, and an automated forging process method for uniform distribution of internal channel streamlines of aviation bearing ring forgings was established. Through small-batch scientific research production, the aviation main bearing ring forgings produced were inspected and the metal streamlines of the low-magnification specimens were uniformly and symmetrically distributed along both sides of the internal channel, which was basically consistent with the simulation. The uniform and symmetrical distribution of the metal streamlines of the bearing ring forging channel was completely consistent with the distribution of the metal streamlines of the bearing design raceway, meeting the technical quality requirements of the bearing design.

[0036] Through process optimization design, the uneven distribution of metal streamlines in the grooves of the main bearing ring forgings, the exposure of streamlines after bearing raceway surface processing and potential quality risks are avoided, thereby improving the service life of the main shaft bearings and aviation flight safety.

[0037] By testing the main shaft bearing ring forgings with optimized process design, it is found that the metal streamlines in the low-magnification microstructure of the ring forgings of the present invention are evenly and symmetrically distributed along the grooves, meeting the requirements of the microstructure state of the main bearing raceway design, and the uneven density of metal streamlines on both sides of the grooves is eliminated. The various technical indicators of the forgings have also reached the expected design goals:

[0038] 1) The grain size of the ring forging is ≥8, and the mixed grain size is <2.

[0039] 2)

[0040] 3) The forging streamline of the ferrule meets the requirements of MMS50003 standard.

[0041] 4) The fracture, carbide and micropores meet the standard requirements.

[0042] The ring forging product of the present invention not only improves product quality, but also solves the product quality problem caused by the fact that metal streamlines cannot be symmetrically and evenly distributed along the channel, meets product design requirements, improves the organizational uniformity of the forging, extends the service life of the bearing, and avoids economic losses caused by batches of scrapped products due to unreasonable distribution and uneven density of metal streamlines in the forging channel.

[0043] The present invention is not limited to the above-mentioned preferred embodiments, and all technical solutions that are the same or similar to the present invention belong to the protection scope of the present invention.

Claims

1. An automated forging process for symmetrical and uniform distribution of metal streamlines in the inner raceway of an aviation bearing, characterized in that: a. Two-station punch: The diverter cone punch punches and diverts the flow, keeping the metal fiber in the inner hole intact without defects such as cutting and bending; b. Two-station mold: The inner wall of the two-station mold cavity is designed to be tapered with a larger top and a smaller bottom, and the slope is consistent with the direction of the punch; c. Hole expansion and through-hole shaping: Use hole expansion punch to expand the hole until it is parallel to the outer diameter without taper, and then use small-angle through-hole punch to shape the inner hole according to the designed size to achieve parallelism between the inner hole and the outer diameter; d. Rolling: The straight inner hole is rolled and expanded. The ring blank is positioned stably on the mandrel. During the rolling and expanding process, uniform and symmetrical deformation is achieved on both sides of the inner hole channel.

2. The automated forging process for symmetrical and uniform distribution of metal streamlines in the inner raceway of an aviation bearing according to claim 1 is characterized by: The inner wall of the second-station mold cavity has a slope of 5°, and the diverter cone punch has a slope of 14°, and the two are inclined in the same direction.

3. The automated forging process for symmetrical and uniform distribution of metal streamlines in the inner raceway of an aviation bearing according to claim 1 is characterized by: After the ring blank is formed, it is transferred by the robot to the third station for bottom cutting and then returned to the furnace for heating; at the fourth station, the inner hole is expanded to the process size and the outer diameter is parallel and without taper. The size and depth of the expanded holes at both ends of the inner hole are symmetrical. At the fifth station, a small-angle through-hole punch is used to shape the inner hole according to the design size. The straight part of the inner hole is parallel to the outer diameter. At the sixth station, the upper and lower end surfaces of the flat width are parallel.

4. The method for automated forging of metal streamlines symmetrically and evenly distributed in the inner raceway of an aviation bearing according to claim 1 is characterized in that The rolling method is as follows: the ring blank is hung on a core shaft with a protruding groove, and is positioned closely with the shaft disc as a reference. The rolling wheel is in direct contact with the outer diameter of the ring blank to roll and expand the ring, and the inner groove is evenly formed.

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